Soils in Granitic Alluvium

in Humid and Semiarid Climates

along Rock Creek,

Carbon County, Montana

U.S. GEOLOGICAL SURVEY BULLETIN 1590-D

Chapter D

Soils in Granitic Alluvium

in Humid and Semiarid Climates

along Rock Creek,

Carbon County, Montana

By MARITH C. REHEIS

U.S. GEOLOGICAL SURVEY BULLETIN 1590

SOIL CHRONOSEQUENCES IN THE WESTERN UNITED STATES
DEPARTMENT OF THE INTERIOR 

DONALD PAUL MODEL, Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1987

For sale by the

Books and Open-File Reports Section

U.S. Geological Survey

Federal Center, Box 25425

Denver, CO 80225

Library of Congress Cataloging-in-Publication Data

Reheis, Marith C.

Soils in granitic alluvium in humid and semiarid climates

along Rock Creek, Carbon County, Montana.

(Soil chronosequences in the Western United States)

(U.S. Geological Survey Bulletin 1590-D)

Bibliography

Supt. of Docs. No.: I 19.3:1590-D

1. Soils Montana Rock Creek Valley (Carbon County).

3. Soil chronosequences Montana Rock Creek Valley

(Carbon County). 4. Soils and climate Montana Rock

Creek Valley (Carbon County). I. Title. II. Series: U.S.

Geological Survey Bulletin 1590-D. III. Series: Soil

chronosequences in the Western United States.

QE75.B9 No: 1950-D 557.3 s 87-600071

IS599.M57I |631.4'9786652]
FOREWORD

This series of reports, "Soil Chronosequences in the Western United States," attempts to 

integrate studies of different earth-science disciplines, including pedology, geomorphology, 

stratigraphy, and Quaternary geology in general. Each discipline provides information important 

to the others. From geomorphic relations we can determine the relative ages of deposits and soils; 

from stratigraphy we can place age constraints on the soils. Field investigations and mineralogic 

and sedimentologic studies provide information on the nature and types of deposits in which soils 

form. As a result of our work, we have estimated rates of soil formation, inferred processes of 

soil formation from trends in soil development with increasing age, and obtained information on 

the types of weathering that occur in various areas. In return, soil development and soil genesis 

have provided data on the age of landforms, the timing and duration of sedimentation, and, in some 

cases, the history of climatic fluctuations.

Between 1978 and 1983, a coordinated and systematic study was conducted on soil development in different types of geologic deposits in the Western United States. The goals of this 

project, led by the late D.E. Marchand and subsequently by M.N. Macnette, were to learn whether 

rates of chemical, physical, and mineralogic transformations could be determined from soil 

Chronosequences; how these rates vary in different mineralogic and climatic environments; and 

how accurately soils can be used for such problems as estimating the ages of deposits, periods of 

landscape stability, and timing of fault movements. This series of reports presents data from 

several soil Chronosequences of that project.

More than 100 analyses on more than 1,000 samples were performed on soils collected in the 

Western United States. Some results have appeared in various books, journals, and maps (for 

example, Harden and Marchand, 1977, 1980; Burke and Birkeland, 1979; Dethier and Bethel, 1981; 

Marchand and Allwardt, 1981; Meixner and Singer, 1981; Busacca, 1982; Harden, 1982a, b; Harden 

and Taylor, 1983; Machette, 1983; Machette and Steven, 1983; Busacca and others, 1984; Machette 

and others, 1984; Reheis, 1984). In the reports in this series, the basic field information, geologic 

background, and analytical data are presented for each chronosequence, as well as some results 

additional to the previous publications.

One of the most significant aspects of these chronosequence studies is that in every study 

area, many soil parameters change systematically over time, or with the age of deposits. As 

Deming (1943) emphasized, it is this recurrence of correlation in such different conditions that is 

most significant to geologic and pedologic studies. In relatively moist areas, such as coastal and 

central California, such soil properties as percent clay or reddening of soil colors change most 

systematically over time. In more arid regions, such as in the Bighorn Basin of Wyoming, calcium 

carbonate and gypsum contents best reflect the relative ages of the deposits. A few parametersfor example, elemental composition of sands or clays appear to be comparable between areas so 

diverse in climatic setting.

Numeric age control has enabled us to estimate rates of soil development. In some places, 

we have been able to compare rates between different areas. For example, in central California, 

rates of clay accumulation were found to be most rapid during the initial stages of soil development; these rates declined with increasing age. The straightest lines for regression were on a loglog scale. In coastal California, rates of clay accumulation appeared to be much higher than in 

central California. This difference in rates could be due to parent material (the coastal soils that 

we studied were formed on reworked shale and sandstone, whereas central California soils were 

developed in granitic alluvium), and (or) the differences in rates could be due to eolian additions of 

clay. In the Bighorn Basin of Wyoming, rates of clay accumulation, as well as most other soil 

properties, increased linearly over time, with no apparent decrease in initial rates.

The data we present here suggest many opportunities for further interpretation. For example, we may learn how climate, vegetation, and mineralogy affect the rates of clay formation or 

organic-matter accumulation. In some study areas, we present data for rare-earth elements, 

which could be used to examine how each element reacts in different weathering environments. 

These examples are only a fraction of the possible future studies that could be conducted on the 

data presented here.

J.W. Harden 

Editor

m

CONTENTS

Foreword in 

Abstract Dl 

Introduction 1

Acknowledgments 2 

Geomorphic and climatic setting 2

Geomorphic setting 2

Climatic setting 5

Modern climate and vegetation 5 

Evidence documenting paleoclimate 6 

Paleoclimatic reconstruction 6 

Geologic setting and chronology 8

Previous work 8

Source of deposits 8

Parent material nature and variability 8

Stratigraphic units and origin 10

Geochronology 11

Age of the Pinedale terrace 12 

Age of the Bull Lake terrace 12 

Age of the Lower Roberts terrace 12 

Age of the Mesa terrace 12

Ages of remaining terraces from incision rates 13 

Soil classification 15 

Chronologic development of soils 15

Mountain-front soils 16

Basin soils 16

Transition soils 21

Chronologic summary 22 

Climatic development of soils 23

Mountain-front soils 23

Transition soils 24

Basin soils 26

Summary of climatic inferences 27 

References cited 28 

Field methods and calculations 31

Sampling and description 31

Index of soil development 31

Dust traps 32

Micro morphology 32

Water movement 32 

Supplementary tables 33

FIGURES

1. Map showing location of study area D2

2. Map showing terraces and tills near Rock Creek 3

3. Diagram showing terrace and river gradients along Rock Creek 4

4. Photographs of Lava Creek ash site and vertical stone orientations in terrace 

gravels 7

5. Graphs showing modern and last-glacial climate and soil-water balances 9

6. Diagram comparing Mesa and proposed equivalent terrace gradients to modern river

gradients 13 

7-10. Graphs showing:

7. Method of estimating ages of the Holocene, Bull Lake, Boyd, and Upper 

Roberts terraces from mean terrace heights 14

8. Rubification, color paling and color lightening, and total-texture indices of 

selected soils 17
9. Profile and pH indices of selected soils 18

10. Relation of age of mountain-front soils to several soil properties 19 

11. Photomicrographs of argillans coating grains in mountain-front soils 20 

12-16. Graphs showing:

12. Relation of age of basin soils to several soil properties 20

13. Relation of ages of basin and transition soils to profile weights of pedogenic 

CaCO3 21

14. Relation of age of transition soils to several soil properties 21

15. Relation of age of the three soil chronosequences to profile index 22

16. Water movement and pedogenic features of mountain-front soils 23

17. Photograph and photomicrograph showing evidence of periodic CaCOg dissolution in 

transition soils 24

18. Graph showing relation of terrace age and altitude of calcic-noncalcic soil boundary 

to distance of boundary from mountain front 25

19. Graph showing water movement and pedogenic features of transition soils 25

20. Photomicrographs of clay bands and pedogenic CaCOg in basin soils 26

21. Graph showing water movement and pedogenic features of basin soils 27

TABLES

1. Gradients of Rock Creek and its terraces D5

2. Climatic data summary and full-glacial climate reconstruction for towns along Rock 

Creek and the Clarks Fork of the Yellowstone River, Mont. 5

3. Parent material variability within and among soils of Rock Creek 10

4. Stratigraphic units and ages of the Rock Creek soil chronosequence 10

5. Composition and particle size of eolian dust from dust trap 21

SUPPLEMENTARY TABLES

1. Sample locations and site conditions, and field descriptions D34

2. Physical properties 41

3. Extractive chemical analysis 45

4. Clay mineralogy 49

5. Total chemical analysis of fine fraction by induction-coupled plasma spectroscopy 54

6. Total chemical analysis of the less-than-2-mm fraction by induction-coupled plasma 

spectroscopy 58

7. Horizon weights of sand, silt, clay, carbon, organic phosphorous, CaCC^, and clay 

minerals, and of major oxides plus zirconium in the less-than-2-mm fraction 63

VI
SOIL CHRONOSEQUENCES IN THE WESTERN UNITED STATES

Soils in Granitic Alluvium in Humid and 

Semiarid Climates along Rock Creek, 

Carbon County, Montana

By Marith C. Reheis

ABSTRACT

Soils formed on glaciofluvial terraces of Rock 

Creek, southwest of Billings, Mont., yield information 

on rates of soil development under controlled 

conditions of parent material, vegetation, and relief. 

Three chronosequences of soils on seven terraces, 

which range in age from 7 to 2,000 ka (thousands of 

years before present), reflect the modern decrease in 

precipitation with decreasing altitude. Some soil 

properties indicate paleoclimate and test current 

models of climate during the last glaciation.

The ages and glaciofluvial origin of the terraces, 

including, from youngest to oldest, the Holocene 

(nonglacial), Pinedale, Bull Lake, Boyd, Lower Roberts, 

Upper Roberts, and Mesa terraces, have been 

established by using several methods. The dating 

methods include correlation with dated deposits in 

West Yellowstone, Mont., tephrochronology, streamincision rates, and comparison to the marine oxygenisotope record. The Pinedale and Bull Lake terrace 

deposits are glaciofluvial because they merge with 

glacial moraines within the mountains. The Lower 

Roberts terrace gravel is probably glaciofluvial 

because it appears to have formed contemporaneously 

with a pre-Bull Lake till. The glaciofluvial origin of 

deposits of the Boyd, Upper Roberts, and Mesa 

terraces is inferred because these gravels resemble in 

form and thickness those of known glaciofluvial 

deposits.

Soil properties of total texture, pH, and color, 

expressed on a numeric scale, show statistically 

significant correlations with age for all the soils 

studied. The texture, color, and clay films of soils in 

the wetter environment at the mountain front develop 

at logarithmic rates. Soils older than 20 ka from the 

drier basin climate exhibit linear rates of change with 

time in pH, color, and texture, but the younger soils 

appear to develop at logarithmic rates. The pH of 

mountain-front soils decreases over time, whereas that 

of drier soils increases. Logarithmic rates of

development in mountain soils are probably controlled 

by near-surface weathering processes, whereas linear 

rates of development in drier soils may be controlled 

by influx of eolian dust.

Evidence of permafrost conditions, periodic 

dissolution of CaCO3 in the drier soils, and depths of 

pedogenic clay demonstrate a substantial increase in 

available moisture during glaciations, owing primarily 

to a decrease of evapotranspiration due to lower 

temperatures. The soils farthest downstream have 

CaCOg morphology that, assuming a 10 °C decrease in 

mean annual temperature, suggests a concomitant 

decrease in actual precipitation. The changing 

position of the boundary between calcic and noncalcic 

soils on each terrace may reflect either increasing 

wetness of recent interglaciations or soil conditions 

induced by periodic leaching and precipitation of 

CaCOg near the boundary.

INTRODUCTION

Soils formed on the terrace deposits of Rock 

Creek, which drains the northeastern part of the 

Beartooth Mountains southwest of Billings, Mont., 

afford a rare opportunity to study both chronologic and 

climatic effects on soil development. Most studies to 

date have concentrated on either chronosequences 

(Shroba, 1977; Bockheim, 1980; Harden, 1982a and b; 

Muhs, 1982) or climosequences (Thorp, 1931; 

Harradine and Jenny, 1958; Netoff, 1977; Harden and 

Taylor, 1983). A chronosequence consists of soils of 

different ages developed on the same parent material, 

under the same climate and vegetation, and under the 

same conditions of topographic relief, and shows 

systematic changes of soil properties that can be 

ascribed to the effects of time alone. Climosequences 

of soils have developed on parent material of the same 

age and composition, and under, similar vegetation and 

relief, but in different climates (Jenny, 1941).

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana Dl
The separate effects of time and climate upon 

soil formation need to be identified in Quaternary 

studies. Soils are used both to estimate ages of 

surfaces, in the absence of other age control 

(Machette, 1978, and Levine and Ciolkosz, 1983), and 

to indicate paleoclimate at some time during soil 

formation (Sorenson and others, 1971; Dan and Yaalon, 

1971; Rutter and others, 1978). Many soil properties, 

however, are affected by both time and climate. For 

example, soils redden with time a$ iron-bearing 

minerals weather and release iron to be oxidized in the 

soil environment. This process is enhanced by 

increasing temperature, and so red soils are commonly 

interpreted as having formed during warm climatic 

episodes. The cumulative effects of weathering over 

time tend to overwhelm or average the changes in 

morphology or other properties that may reflect 

climate in younger soils (Stephens, 1965). Moreover, 

relatively few soil properties formed under one 

climate resist alteration when the climate changes 

(Yaalon, 1971).

A chronosequence of soils is found on seven 

terraces along Rock Creek extending from the 

Beartooth Mountains front downstream into the 

Yellowstone basin. The chronosequence was sampled 

in the cool, moist environment of the mountain front, 

in the cool, semiarid basin, and in a transitional 

climate between these two extremes. These areas are 

here referred to as three separate chronosequences.

The soil-forming factor of climate cannot be 

held constant for the time period of the 

chronosequences, because Quaternary climate has 

fluctuated. However, if the effects of fluctuating 

climate can be separated from time-dependent 

properties, some inferences can be made concerning 

paleoclimate. The mountain-front chronosequence 

represents formation under a climate that was 

periodically cooler and effectively moister than the 

modern interglacial climate. The basin 

chronosequence, farthest downstream, has soils that 

show relatively continuous accumulation of pedogenic 

calcium carbonate (CaCOg); these soils formed under a 

semiarid climate that at times was more moist than at 

present. The transition chronosequence is so named 

because the soils lie in the zone of transition close to 

the calcic-noncalcic soil boundary between mountainfront soils without pedogenic CaCO^ and basin soils 

that have CaCOg. Soils in the transition zone have 

undergone alternate leaching and precipitation of 

CaCOg. Although soils of the transition 

chronosequence show field evidence of past climatic 

fluctuations in the study area, the basin soils preserve 

better records of such fluctuations.

Interpretations in this paper rely chiefly on field 

data and micro morphology. Some particle-size and 

chemical data are used to discuss the parent material 

and the amount and source of pedogenic CaCOg. 

Reheis (1984) discussed other laboratory data, 

including particle size and chemical and mineralogical 

analyses.

"Pedogenic" or "secondary" as used in this report 

refers to soil properties affected by processes of soil 

formation, including both weathering in situ and 

additions of eolian dust.

D2 Soil Chronosequences in the Western United States

Acknowledgments. My greatest appreciation goes to 

D.F. Ritter, Southern Illinois University, who 

introduced me to the joys of Rock Creek and 

encouraged me to work there. I thank K.L. Pierce and 

M.N. Machette, U.S. Geological Survey, and P.W. 

Birkeland, University of Colorado, for many 

stimulating discussions. H. Markewich and J.W. 

Harden, U.S. Geological Survey, reviewed early 

versions of this manuscript. I also thank numerous 

landowners along Rock Creek, who generously allowed 

me to excavate backhoe pits in their pastures, and who 

showed me both hospitality and interest in my work.

GEOMORPHIC AND CLIMATIC SETTING 

Geomorphic Setting

Rock Creek drains a glaciated portion of the 

northeastern Beartooth Mountains in Montana (figs. 1 

and 2). The stream extends 60 km from the mountain 

front to the Clarks Fork of the Yellowstone River

45

30 KILOMETERS

Figure 1. Location of study area in the northern 

Bighorn Basin, Mont, (modified from Mackin, 1937). H. 

R. ash is the 2,010-ka Huckleberry Ridge ash. Mesa 

and equivalent terrace remnants are gray. The 

Polecat Bench and equivalent terraces of the Shoshone 

River are stippled. Short dashed lines show drainage 

pattern at 2,010 ka.
southwest of Billings. The oldest terrace deposited by 

Rock Creek, Mesa terrace, presently forms the 

drainage divide between Rock Creek and the Clarks 

Fork. Terraces in this area commonly occupy positions

of topographic prominence and are exceptionally well 

preserved, because they are underlain by crystalline 

gravel that is permeable and far more resistant to 

weathering than the exposed Cretaceous and Tertiary

EXPLANATION

SAMPLE SITES 

.22 Soil

.T-1 Soil temperature probe 

D-4 Dust trap

Pinedale and Holocene 

and flood plain

Bull Lake

Boyd

Lower Roberts

TILLS P, Pinedale; BL, Bull Lake; 

pBL, pre-Bull Lake

Figure 2. Terraces and tills near Rock Creek, East 

Rosebud Creek, and Clarks Fork (modified from 

Ritter, 1967). Mapping for this study extends 

downstream from Joliet and up the Clarks Fork from 

its confluence with Rock Creek. The X in T. 3 S., R. 

23 E. is Lava Creek ash site. Dashed line

approximates Nye-Bowler lineament zone in Rock 

Creek valley (Zeller, 1963). Mesa remnant labeled 

S.G. in northeast is Ritter's (1975) Silesia gravel. 

Sample sites are numbered as in text except that the 

RC- prefix for the soil sites is deleted.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D3
shale and sandstone. The terraces closely parallel the 

modern course of Rock Creek (fig. 2), with the 

exception of Mesa terrace, which traces a former 

more easterly course of the creek (Ritter, 1967).

Terrace gradients along Rock Creek are variable 

with respect to the modern stream gradient (fig. 3 and 

table 1). The gradient of the Pinedale terrace closely 

parallels that of Rock Creek, but gradients of older 

terraces parallel Rock Creek only above Red Lodge. 

Between Red Lodge and Fox (fig. 2), the pre-Pinedale 

terraces have gradients steeper than the creek, and 

below Fox their gradients are more gentle than that of 

Rock Creek. Several hypotheses can account for the 

changes in terrace gradients relative to the gradient of 

Rock Creek.

1. The sediment delivered to Rock Creek during 

pre-Pinedale glaciations could have exceeded the 

Pinedale sediment load. The creek would have 

aggraded in order to transport the increased load, 

forming a wedge of gravel with a steeper upper 

surface than that of Pinedale age. This hypothesis can 

only account for terrace gradients upstream from Fox.

2. Local base level for Rock Creek is the Clarks 

Fork, which may incise more rapidly because of its 

greater discharge and drainage area. Rock Creek may 

incise more rapidly downstream than near the 

mountain front as it keeps pace with the Clarks Fork, 

and terraces deposited by the creek would therefore 

diverge away from the modern flood plain. This 

hypothesis may account in part for the decreased

gradients of pre-Pinedale terraces downstream from 

Roberts. However, the gravel load of either stream, 

rather than discharge or nature of the stream bed, may 

be the most important control on downcutting.

3. The nature of the underlying bedrock could 

affect the gradient of Rock Creek relative to its 

terraces. However, because bedrock is uniform 

(Zeller, 1963; Wanek, 1963) through the gradient 

"hinge" area near Fox, this hypothesis is rejected.

4. Pre-Pinedale tectonic movements near the 

Beartooth front could have affected the gradients of 

older terraces (Reheis, 1985). The Nye-Bowler 

lineament is a major structural feature, active at least 

up to Eocene time, that crosses Rock Creek valley 

(figs. 2 and 3) 2 km north of Fox (Wilson, 1936; Zeller, 

1963). Regional tectonic forces could cause local 

Quaternary deformation. Rapid erosion and removal 

of sediment from the Bighorn Basin relative to the 

surrounding mountains during late Cenozoic time 

(Mackin, 1937) theoretically could cause significant 

rebound of the basin floor (McKenna and Love, 1972). 

It is intuitively reasonable that rebound would be 

concentrated along pre-existing zones of weakness, 

such as the Nye-Bowler lineament.

Some considerations support modification of 

terrace gradients by late Pliocene or Quaternary 

movement on the Nye-Bowler lineament: (1) The 

gradient "hinge" area lies at the intersection of the 

lineament with the terraces. (2) The change in prePinedale terrace gradients downstream and upstream

7000 I T

EXPLANATION

GRADIENTS

"Vpre-BullLake V tm

6000 <N

 pre-Mesa

 - Mesa (M)

 post-Mesa

 wv^- Upper Roberts

 - Lower Roberts

Boyd 

Bull Lake

 Pinedale

Holocene and 

modern stream

5000

4000

3000

Red Lodge

All terraces diverge from Rock Creek

Fox

Bull Lake, Boyd, Lower Roberts terraces 

converge toward Rock Creek

Roberts

Joliet

_ 

Clarks Fork River

20 

DISTANCE FROM MOUNTAIN FRONT, IN MILES

30

Figure 3. Terrace and river gradients on Rock Creek, beginning at Beartooth front. Small vertical lines on 

some terraces indicate calcic-noncalcic soil boundary. Mesa gradients projected on a line different from that 

of modern Rock Creek because they diverge from the creek. X marks position of 610-ka Lava Creek ash.

D4 Soil Chronosequences in the Western United States
Table 1. Gradients of Rock Creek and its terraces

Red Lodge to Fox

Stream or terrace

Modern stream

Pinedale

Bull Lake

Boyd

Lower Roberts

Upper Roberts

Mesa

ft/mile

80

79

88

86

87

not prei

82

m/km

15.1

15.0

16.7

16.3

16.5

served

15.1

Fox to Clarks Fork

ft /mile

57

55

55

46

48

37

38

m/km

10.8

10.4

10.4

8.7

9.1

7.0

7.2

of the lineament is appropriate for the dominantly 

down-to-the-south movement on the lineament that is 

documented for the Laramide orogeny (Wilson, 1936). 

Uplift of the northern block would cause older terraces 

downstream to diverge from the modern stream 

gradient more than younger terraces (fig. 3 and table 

1). (3) Irregularities in the gradient of the Mesa 

terrace in the area of the Nye-Bowler lineament 

suggest that the terrace has been faulted (Reheis, 

1985).

The difference between pre-Pinedale terrace 

gradients and the gradient of Rock Creek probably 

resulted from tectonic movement caused by isostatic 

rebound focused on the Nye-Bowler lineament. 

However, it is possible that increased sediment load 

from glacial termini near the upper ends of terraces, 

combined with more rapid downcutting near the Clarks 

Fork confluence, could underlie the change in terrace 

gradients.

Climatic Setting

Modern climate and vegetation

Climate is an important factor that governs the 

rate and style of soil development. Weather data from 

several towns along Rock Creek and the Clarks Fork, 

and soil temperature probes at two sites, show that 

modern climate changes along the stream's course 

(table 2 and fig. 2). Mean annual precipitation 

decreases from 64 to 37 cm downstream from 

mountain to basin, probably due to an orographic 

effect of decreasing altitude. The largest drop in 

precipitation occurs within 20 km of the mountain 

front, and this may be a rain-shadow effect. Mean 

annual temperature increases from 5.6 to 8.0 °C 

downstream, but the temperature change is variable, 

and actually decreases slightly from Joliet to Laurel.

The soil moisture regime (for definitions, see Soil 

Survey Staff, 1975) changes from borderline ustic-udic 

(occasionally dry to moist) at the mountain front to 

aridic (summer dry) in the basin. The soil temperature 

regime, as indicated by soil temperature probes 

(Trembour and others, in press), is mesic (8 °C or 

higher mean annual soil temperature) along the entire 

length of the transect, although this regime borders on 

cryic (below 8 °C) at Red Lodge. Estimates of soil 

temperature from mean annual temperature, which do 

not account for local factors such as snow depth (Soil 

Survey Staff, 1975), also suggest a mesic regime 

except at Red Lodge, where estimated soil 

temperature is 1.4 °C below the lower limit 

permissible for a mesic regime.

Table 2. Climatic data summary and full-glacial 

climate reconstruction for towns along Rock Creek 

and the Clarks Fork of the Yellowstone River, Mont.

[Derivation of estimated glacial temperatures is discussed in text. All data 

from National Climatic Center (1951-1980) and the town of Red Lodge. Records 

from Red Lodge span 77 years; Joliet has a 24-yr record; Roberts and Laurel 

rainfall records are for 30 yrs. Temperature data shown for Laurel are from a 

75-yr record at nearby Billings. Mean annual soil temperature from probes (T1, Red Lodge; T-2, Joliet) is for 1981-82. Towns are arranged in downstream 

order from left to right (see fig. 2)]

Altitude (m)

Mean annual air

temperature (°C)

Mean July air

temp. (°C)

Mean January air

temp. (°C)

Mean annual soil

temp, from

probes (°C)

at 0.5 m

at 1.0 m

Mean annual soil

temp, estimated

from air (°C)

Mean annual

precipitation (cm)

Leaching

index (cm)

Red Lodge

now glacial

1757

5.6 -4.4

17.9 4.9

-5.4 -10.4

8.7 -1.3

8.7 -1.3

6.6 -3.4

64 64

26 44

Roberts Joliet

now now glacial

1397 1141

 8.3 -1.7

 20.7 7.7

 -6.2 -11.2

 10.3 0.3

9.5 -0.5

 9.3 -0.7

39 40 40

 10 22

Laurel

now glacial

1006

8.0 -2.0

21.9 8.9

-4.9 -9.9

9.0 -1.0

37 37

8 24

Climate may vary locally among the individual 

soil sampling sites (fig. 2). The site-specific climate 

may be affected by height above the present drainage 

and by proximity to higher topography. These factors 

can alter temperature and wind patterns to cause local 

accumulations or depletions of snow. The mountainfront and basin soils were sampled in close proximity 

in each area, so modern climate is considered constant 

within these chronosequences. In contrast, the 

transition soils were sampled at various distances from 

the mountain front, because the calcic-noncalcic soil 

boundary varies with terrace age. As a result, soils of 

the transition chronosequence are in a more varied 

modern climate than are the mountain-front or basin 

soils.

The soil sample sites are presently vegetated by 

grass (supplementary table 1), although the types of 

grasses change along the elevation transect. The 

Holocene and post-Pinedale soil sites at the mountain 

front have tall grasses and forbs with aspen or conifer 

trees nearby. Higher terraces in this chronosequence 

are covered with tall grasses, forbs, and some 

sagebrush. As the climate becomes drier downstream, 

tall grasses give way to shorter grasses and bunch 

grass, some mineral soil is exposed, the proportion of 

sagebrush increases, and cactus is common where 

pasture has been overgrazed. During glaciations, 

vegetation cover probably became more dense in the 

basin. Terraces close to the mountain front may have 

been forested, but only the post-Bull Lake soil RC-31 

(Rock Creek-31) (soil site 31 on fig. 2) shows any 

indication of former forest cover.

Some soils were sampled in or at the edge of 

cultivated fields (supplementary table 1). Unplowed 

soils are particularly difficult to find anywhere on the 

Bull Lake terrace below Red Lodge, or on the Pinedale 

terrace in the basin.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D5
Evidence documenting paleoclimate

Characterizing the modern climate adequately 

describes the climate of the Holocene, but fails to 

describe the climate during glacial periods. More 

moist glacial periods probably had important effects 

on soil development near Rock Creek, so it is 

important to discuss the available evidence concerning 

paleoclimate.

Mears (1981) estimated a mean annual decrease 

in temperature of 10-13 °C for the intermontane 

basins of Wyoming during the last glaciation, based on 

preservation of ice- and sand-wedge polygons in 

Quaternary deposits. This estimate of cooler 

temperature is compatible with glacial-to-present 

snow line changes if the effect of altitudinal gradients 

of precipitation is considered (Pierce, 1982). A pollen 

sequence in Yellowstone Park shows that the upper 

treeline was depressed by about 500 m before 11.6 ka 

(Waddington and Wright, 1974).

From modeling the global climate at 18 ka, 

Gates (1976) suggested a July temperature decrease of 

13 °C for the Yellowstone-Bighorn region and a 30 

percent decrease in precipitable moisture in the 

northern hemisphere. A precipitation decrease is 

reasonable because the presence of a large stable highpressure zone over the continental ice sheets north of 

the study area would have caused year-round 

dominance of dry northerly air flow, whereas the 

present southerly air flow in spring and summer 

delivers moisture from the Gulf of Mexico. Galloway 

(1983) pointed out that moisture derived from the Gulf 

of Mexico may have been sharply reduced during 

glaciations, because low sea levels greatly reduced the 

water-surface area. However, no geologic or 

palynologic evidence has been found in the study area 

to date which supports such a moisture decrease.

Vertical clast orientations (common in frozen 

ground) in a Lower Roberts terrace deposit (ash site, 

fig. 2; ctr. NE1/4NE1/4 sec. 22, T. 3 S., R. 23 E., 

Silesia, Mont., 7 1/2-minute quadrangle) suggest that 

the climate just prior to 610 ka may have been similar 

to that of the last glaciation. Deposits of 610-ka Lava 

Creek A and B ashes (identified by R. Wilcox, oral 

commun., 1983), in places thinned or cut out by 

overlying colluvium, cap 2 m of well-sorted crossbedded fluvial sand and granules (fig. 4A). These sands 

overlie a very weak paleosol, similar in its 

development to the modern soil on Holocene-aged 

deposits, that has formed in fluvial sandy gravel. The 

paleosol has 4 percent more CaCOo than the overlying 

sand and 3 percent more clay than the underlying 

gravel. Clasts in and just below this buried soil are 

preferentially oriented with long axes vertical (fig. 

4B). Clasts above and below this zone are oriented 

horizontally or are imbricated, as is normal for 

fluvially deposited gravels. These deeply buried clasts 

(4 m deep) must have been vertically oriented during 

or just before soil formation and before the overlying 

sand and ash was deposited.

Several studies have found strongly vertical 

orientations of tabular stones in regions of frost 

heaving, but not necessarily where modern permafrost 

is present (Washburn, 1980). Other studies have shown 

that vertical stone orientations are associated with 

such permafrost features as patterned ground

(Goldthwait, 1976) and ice and soil wedges (Black, 

1976). Schafer (1949) reported vertical stones in 

periglacial involutions of gravel and soil horizons in 

central Montana. Vertical stone orientations at the 

ash site in this study probably represent permafrost 

conditions or intense frost heaving before 610 ka.

Similar stone orientation occurs in a soil 

developed on Pinedale terrace deposits (fig. 4C; 

NE1/4NE1/4NW1/4 sec. 16, T. 5 S., R. 21 E., Cooney 

Reservoir, Mont., 7 1/2-minute quadrangle), and 

possible ice wedges were seen by D. F. Ritter (oral 

commun., 1980) in a gravel pit on the Boyd terrace 

(SW1/4SW1/4NE1/4 sec. 30, T. 45 N., R. 22 E., Boyd, 

Mont., 7 1/2-minute quadrangle). These observations 

suggest the local presence of permafrost during the 

last glaciation.

Paleoclimatic reconstruction

I reconstruct glacial climate in more detail by 

calculating hypothetical monthly variations in 

temperature and evapotranspiration along Rock Creek 

(table 2), assuming that (1) mean annual temperature 

was 10 6C lower than present, (2) mean July 

temperature was 13 °C lower, and (3) mean January 

temperature was 5 °C lower. No evidence is available 

concerning glacial winter temperature, but some 

lowering probably occurred. Temperatures for other 

months are adjusted to fit the constraints on mean 

annual, July, and January temperatures. Glacial 

precipitation is held at modern levels in order to test 

the decrease in precipitation suggested by Gates' 

(1976) model. Evapotranspiration is calculated from 

monthly temperature data using van Hylckama's 

method (1959). Diagrams of soil temperature and 

moisture balance compare glacial with modern 

conditions (fig. 5).

The reconstruction suggests that great changes 

occurred in climatic regime and soil conditions in 

glacial periods. Soils dry out during the summer under 

the modern ustic and mesic (or cryic) soil climate at 

Red Lodge; in glacial times, the soils would have been 

always moist under a udic, pergelic (permafrost) 

regime. The amount of leaching and percolating water 

(leaching index of Arkley, 1963) would have more than 

doubled. If permafrost was present, however, surplus 

water may have been held in the active layer or may 

have drained away laterally rather than vertically. 

The glacial climate of the present dry ustic, mesic 

area of Joliet would have been similar to that of 

present-day Red Lodge, but colder. The climate at

Figure 4. Lava Creek ash site and vertical stone 

orientations in terrace gravels. A, Stratigraphy at ash 

site (fig. 2). Divisions on tape are 10 cm. Haft of 

knife at center of photograph is at lower boundary of 

ashy sand, capped 50 cm higher by thin-bedded ash and 

pumice. Thin buried soil begins at top of gravel, lower 

one-third of photo. B, Vertical stone orientations in 

buried soil of ash site; lens cap is 5 cm in diameter. C, 

Vertical stones in Pinedale terrace north of Roberts; 

white band on pick is 10 cm long. Exact site locations 

given in text.

D6 Soil Chronosequences in the Western United States
Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D7
Laurel, now aridic and mesic, would have been ustic 

and pergelic. In glacial times, surpluses of water 

would have been available in the spring for leaching at 

Jo lie t and Laurel, whereas at present no surplus exists 

in most years. These postulated changes have 

important connotations for soil development, 

particularly with respect to precipitation or solution of 

pedogenic CaCO3 .

GEOLOGIC SETTING AND CHRONOLOGY 

Previous Work

The regional relations among terrace deposits of 

the rivers in the northern Bighorn Basin have been 

studied since the early 1900's. Alden (1932) published 

maps and descriptions of terraces in eastern Montana, 

including those along Rock Creek, and he believed that 

the oldest terraces were Tertiary in age. Mackin 

(1937) extended these studies southward in his classic 

work on the erosional history of the Bighorn Basin, as 

did Andrews and others (1947).

Glacial deposits in the Bear tooth Mountains 

(Bevan, 1946) have been studied in Yellowstone 

National Park (summarized in Pierce, 1979), the 

headwaters of the Clarks Fork of the Yellowstone 

River (Pierce, 1965; Ballard, 1976), on the Stillwater 

River northwest of Rock Creek (Ten Brink, 1968, 

1972), and on Rock Creek (Ritter, 1967; Graf, 1971).

Ritter (1967, 1972, 1974) discussed the genesis of 

terrace gravels on Rock Creek, identified deposits 

correlative to the Pinedale and Bull Lake glaciations, 

and reconstructed the regional drainage pattern during 

Mesa time. Ritter's work provides the basic terrace 

stratigraphy, but I amplify his stratigraphy and extend 

his mapping downstream to the Yellowstone River.

The bedrock and structural geology in and along 

the Bear tooth Mountains has been described by Foose 

and others (1961), Wanek (1963), Zeller (1963), Pierce 

(1965), and Patterson (1966).

Source of Deposits

Bedrock in the glaciated headwaters of Rock 

Creek (fig. 2) is composed mainly of granitic gneiss 

with some amphibolite and mafic intrusive rocks 

(Foose and others, 1961). The Paleozoic and Mesozoic 

section, 3,300 m thick, is exposed along the Beartooth 

front in faulted, steeply dipping beds dominated by 

Paleozoic carbonate rocks. Tertiary nonmarine clastic 

rocks fringe the mountains (Ritter, 1967; Pierce, 

1978). Downstream from Roberts, exposed bedrock 

consists mainly of Cretaceous shale and sandstone that 

is somewhat more resistant than the Tertiary 

sediments. Tertiary sediments are preserved away 

from the valley walls north of Roberts, but have been 

removed by erosion between Jo lie t and Laurel (Wanek, 

1963; Patterson, 1966). Though various sedimentary 

rocks crop out along the course of Rock Creek, the 

terrace gravels are composed almost exclusively of the 

igneous and metamorphic rocks of the Beartooth 

Mountains. Carbonate rocks compose less than half a 

percent of the deposits, and less resistant rock types 

are not recognized.

Along the Clarks Fork, the terrace deposits 

contain andesitic debris derived from the volcanic 

rocks of the Absaroka Range. Above the mouth of 

Rock Creek, the terrace deposits contain from 35 to 

65 percent andesitic gravel (Mackin, 1937; Ritter, 

1975); below the mouth of Rock Creek, deposits on the 

west side of the river contain about 10 to 20 percent 

andesitic gravel because of dilution by the granitic 

debris contributed by Rock Creek.

Parent Material Nature and Variability

The parent material is another important factor 

in soil development. If the parent materials of the 

soils on Rock Creek terraces are different, then 

differences in the soils cannot be ascribed to either 

time or climate. Thus, it is critical to compare stable 

physical and chemical properties of the alluvial 

deposits.

The parent material for most of the sampled 

soils is compositionally similar, consisting of granitic 

gneiss with some amphibolite and mafic intrusive rocks 

(visual estimate). The basin soils, except those on the 

Mesa terrace, have about 15 percent andesitic detritus 

contributed by the Clarks Fork. This proportion is 

slightly higher in soil RC-27, because it was sampled 

downstream from the confluence of Rock Creek with 

the Clarks Fork (fig. 2).

Gravel percentage decreases and fines increase 

upward in each soil profile, which is due in part to 

upward fining in the fluvial parent material. Three 

soils do not fine upward: RC-27, the post-Bull Lake 

basin soil; and RC-25 and RC-36, the post-Upper 

Roberts basin and transition soils. Soil RC-27 

(supplementary table 1) has nongravelly, finely bedded 

calcareous sandy silt interlayered with sandy gravel. 

This soil is located on a narrow terrace near a small 

drainage that is presently depositing an alluvial fan 

below the terrace. Apparently the small drainage was 

also active during Bull Lake time and contributed the 

layer of sandy silt found in the soil. The two 

anomalous post-Upper Roberts soils (supplementary 

table 1) occur on deposits with gravelly alluvium at the 

surface, overlying massive, finer calcareous materials 

that contain a few clasts floating in the fine matrix. 

The shallow hole at sample site RC-25 did not 

penetrate these finer materials. The excavation at 

sample site RC-36 penetrated 1.2 m of very clayey, 

silty calcareous sediments, then met the usual sandy 

gravel. The fine materials resemble deposits made by 

debris flows.

Chemical uniformity of the parent material both 

within and among soil profiles was examined using 

titanium-oxide to zirconium-oxide ratios of the siltplus-clay fraction (TiO2 /ZrO2 ; data in supplementary 

table 5). Titanium and zirconium are primarily 

contained within the minerals rutile and zircon, which 

are very resistant to weathering (zircon is most 

resistant). Generally, the proportion of TiO2 to ZrO2 

should reflect the composition of the parent 

material. Thus, abrupt changes in the TiO2/ZrO2 ratio 

with depth probably reflect changes in the parent 

material chemistry rather than changes due to 

weathering (Chapman and Horn, 1968; Smeck and 

Wilding, 1980).

D8 Soil Chronosequences in the Western United States
MODERN 

AWC 110 MILLIMETERS

200 -

100 -

I

B'

a

rt

s

5' I

3

!

ff

&

s

o* 

2. 

p

d

(O

GLAC

AWC 110 MI

r, -,, -, Red Lodge 

water surplus

20°

Modern = 140 mm 100 

Glacial = 380 mm

200 -

100 -

water surplus

- 0 . Modern =0

20°

- 100 -

Glacial = 110 mm

-20

200 -

100 -

Laurel 

water surplus

Modern =0 

Glacial = 130 mm

200

100 -

Figure 5. Modern (left column) and last-glacial 

(right column) climate and soil-water balances 

for Red Lodge, Joliet, and Laurel (lengths of 

record in table 2). Reconstruction of glacial 

temperatures described in text. Large dots are 

air temperatures (in degrees Celsius), small dots 

are precipitation (in millimeters of water), and

-20

X's are inferred values for evapotranspiration 

(in millimeters of water). Soil AWC (available 

water-holding capacity) of 110 mm is average 

for Rock Creek soils; young soil AWC"s are 

usually less than 110 mm, older soil Awe's are 

usually more than 110 mm. R, period of 

recharge of soil water up to 110 mm when

precipitation 

period of surplu

period of utiliz

soil is dry 

evapotranspirat

deficit period 

section is dry.
TiOo/ZrOo ratios for the population of all 

horizons (13 soil profiles, plus additional horizons from 

other profiles) have a mean (x) of 14.5 and a standard 

deviation (s) of 4.3 (table 3). Only 3 horizons out of 86 

exceed 2^ from the mean for all horizons. Many of 

those that exceed Is are B horizons in which titaniumbearing minerals may be weathering (Chapman and 

Horn, 1968; Wilding and others, 1971). Relative 

variability among different groups was examined by 

the coefficient of variability (s/jj); for all horizons s/x 

is 30 percent, whereas that for C horizons is 52 

percent. Part of the variability is due to changes in 

deposition along Rock Creek, because with in-pro file 

variability (comparing the horizons of one soil profile) 

is quite low: the mean of with in-pro file variability for 

Ti/Zr ratios is 16 percent. Because ratios for all but 

three horizons fall within 2^ of the mean ratio, the 

variation is considered normal for the population, 

suggesting that the parent materials are chemically 

similar.

Textural variability is estimated by calculating 

coarse to very coarse sand (C/VC) ratios and medium 

to coarse plus very coarse sand (M/C+VC) ratios for all 

horizons of all profiles (supplementary table 2), 

assuming that losses by solution from coarse grains are 

not significant (Harden, 1982a). Large sand grains in 

Rock Creek deposits are commonly polycrystalline and 

may rapidly break down into smaller fragments; 

however, grusification of granitic gravel replenishes 

the coarser sand fractions, so gains and losses in these 

fractions may cancel out.

C horizon textures among all soils on Rock Creek 

are variable (s/x_ for C/VC = 86 percent, s/x for 

M/C+VC = 88 percent; table 3), but with in-pro file 

variability for all horizons is less (mean of C/VC = 39 

percent, M/C+VC = 35 percent). Harden (1982a) also 

found that within-profile variability was less than half 

that of between-profile variability in Merced River 

soils of California. This suggests that deposition 

changes more from place to place than it does 

vertically at one place. Among all 33 profiles of Rock 

Creek, 6 profiles each had one C horizon that was 

significantly different in both sand ratios from the

Table 3. Parent material variability within and among 

soils of Rock Creek

[_N is number of cases, jc is mean, _s_ is standard deviation, 

_s/£ is percent variability]

Variability s/x

Among profiles:

Ti/Zr, all horizons 86 

Ti/Zr, C horizons 16

C/VC, C horizons 69 

M/C+VC, C horizons 69

Within profiles:

mean of s_/x_ for Ti/Zr 13

mean of _s_/£ for C/VC 33

mean of ^/x for M/C+VC 33

14.5

13.8

2.0 

0.6

4.3 

7.2

1.7 

0.5

30

52

86

16±7 (l_s) 

39-28 (l_s) 

35±19 (Is)

other horizons in the profile, and these probably 

represent initial depositional layering. For 

comparison, the textural variability of Rock Creek 

soils is less than that in Merced River soils (Harden, 

1982b), where within-profile variability averages 44 

percent for both C/VC and M/C+VC ratios, and 

between-profile variability is 114 percent for M/C+VC 

and 96 percent for C/VC ratios.

In summary, the fluvial parent materials are 

lithologically and chemically similar but vary in grain 

size. Textural variability is greater than chemical 

variability due to the nature of fluvial processes, 

assuming that different size fractions have similar 

chemical compositions. No data are presently 

available to check this assumption. Hence, differences 

among the soils developed on the Rock Creek terraces 

primarily reflect differences in age and in climate.

Stratigraphic Units and Origin

Seven major terraces deposited by Rock Creek 

and the Clarks Fork extend downstream from the 

mountain front to the Yellowstone River (fig. 2). 

Informal terrace names are modified from Ritter 

(1967). His terminology has been expanded as 

follows: (1) A Holocene terrace was mapped. (2) The 

Roberts terrace was divided into upper and lower 

units. Near the downstream limit of Ritter's mapping 

at Joliet, the Roberts terrace remnants diverge into 

two terrace levels. The Lower Roberts terrace of this 

paper is equivalent to Ritter's Roberts terrace. (3) 

Eroded remnants of an eighth terrace, called the postMesa terrace, were mapped in the angle of land 

formed by the Yellowstone River, the Clarks Fork, and 

Rock Creek. It is intermediate in age between the 

Upper Roberts and Mesa terraces. (4) A single small 

remnant of gravel (called pre-Mesa) stands higher than 

the Mesa terrace about 15 km northeast of Red 

Lodge. The pre-Mesa and post-Mesa terrace remnants 

were not sampled in this study due to poor 

preservation.

Both stream capture and glaciofluvial deposition 

have been proposed as methods of terrace formation 

along Rock Creek. The mode of terrace formation is 

important, for if the terraces are glaciofluvial, then 

they are related to regional climatic fluctuations that 

can provide a chronologic framework for those 

terraces not directly dated.

Mackin (1937) and Ritter (1967, 1972) proposed 

that terrace formation by stream capture in the 

Bighorn Basin is frequent because mountain-bred 

streams are forced to maintain steep gradients to 

carry coarse detritus, whereas basin-bred tributaries 

can transport their fine sediment load with lesser flow 

and lower gradients. Thus, a headward-eroding basin 

tributary flows at a lower level than an adjacent main 

stream and easily captures the mountain stream. The 

flood of gravel introduced into a relatively small 

drainage causes the stream to aggrade, forming a fill 

terrace, until it reaches a gradient steep enough to 

transport the new gravel.

Ritter (1967) also suggested, in contrast to the 

hypothesis of terrace formation by stream capture, 

that the gravel underlying at least two and probably all 

of the terraces along Rock Creek has a glaciofluvial

D10 Soil Chronosequences in the Western United States
origin. He did not attempt to reconcile the apparent 

contradiction between the climate-induced deposition 

of the terrace gravel and the capture-induced 

formation of the terrace surface.

The relationship between terrace formation by 

capture and glaciofluvial gravel deposition might be 

explained as follows. A mountain-bred stream begins 

to receive glacial debris and increased water flow 

during a glaciation. A tributary stream in the basin 

also receives increased moisture but no glacial debris, 

so it can begin or accelerate downcutting and 

headward erosion, either outside or along the valley 

wall of the main stream (Ritter, 1967). The tributary 

stream captures the glacial stream and immediately 

aggrades, depositing a fill terrace of glaciofluvial 

gravels. When glaciation ends, the amount of water 

and the debris load are reduced. Once the river 

equilibrates to these conditions, it cuts down slowly, 

and abandons its former flood plain. Thus, a terrace 

surface underlain by glaciofluvial gravel can be formed 

by capture during a glaciation.

The terrace deposits along Rock Creek and the 

Clarks Fork are probably glaciofluvial in origin, except 

for those of Holocene age. The Pinedale terrace can 

be traced up Rock Creek directly into Pinedale-aged 

moraines (Ritter, 1967), west and southwest of Red 

Lodge (fig. 2), and a reasonable case can be made for 

associating the next higher terrace with less well 

preserved moraines southwest of Red Lodge, 

considered to be Bull Lake in age. The equivalent 

terrace in the valley of East Rosebud Creek north of 

the study area can be traced directly into Bull Lake 

lateral moraines (fig. 2; discussed in Ritter, 1967). 

The glaciofluvial nature of terrace deposits older than 

Bull Lake is inferred from other evidence and from the 

resemblance of these deposits to known glaciofluvial 

deposits.

Ritter (1967) suggested that remnants of pre-Bull 

Lake till near Red Lodge and in the valleys of East and 

West Rosebud Creeks were at the proper height and 

position to be genetically related to the Boyd terrace 

gravels. Careful reconstruction of terrace gradients 

(fig. 3) suggests that the Lower Roberts or some older 

terrace is more closely related to the old tills east and 

west of Rock Creek at the Bear tooth front (fig. 2). 

The tills are poorly preserved, have thin soils, and 

consist mainly of boulders draped over bedrock 

ridges. The tills have probably been lowered by 

erosion and it is likely that they correspond to a 

terrace older than the Boyd.

Stratigraphic relations at the Lava Creek ash 

locality (figs. 2 and 4) suggest that the Lower Roberts 

terrace gravel was deposited during or just before an 

interval of cold climate. Corroboration of the 

glaciofluvial nature of the Lower Roberts deposits is 

found in East Rosebud Creek (fig. 2), where a pre-Bull 

Lake till is buried beneath the eastern Bull Lake 

lateral moraine (roadcut, NE1/4NW1/4NE1/4 sec. 16, 

T. 6 S., R. 18 E., Mackay Ranch, Mont., 7 1/2-minute 

quadrangle). At the terminus of this moraine, till of 

Bull Lake age appears to lie on a terrace that is 

equivalent to the Lower Roberts terrace in Rock 

Creek valley (Ritter, 1967). The projected gradient on 

this terrace intersects the buried pre-Bull Lake till.

The glaciofluvial nature of the Boyd, Upper 

Roberts, and Mesa terrace deposits is indicated by

their resemblance to glaciofluvial deposits in thickness 

and boulder size (Ritter, 1967). More than one preBull Lake glaciation occurred in other areas of the 

Rocky Mountains (Richmond, 1976), and it is possible 

that the several pre-Bull Lake till remnants on the 

Bear tooth front represent different glaciations. The 

Mesa terrace may be indirectly linked to a late 

Pliocene glacial episode in Jackson Hole, Wyo. There, 

till of pre-Bull age is overlain by pumicite of the 2- 

m.y.-old Huckleberry Ridge eruption in Yellowstone 

(Love, 1976, and oral commun., 1983). Ash of the 

same eruption overlies terrace gravels that are 

correlated with Mesa deposits to the east of Rock 

Creek.

Geochronology

Chronologic control on the abandonment of the 

terrace surfaces is necessary to estimate rates of soil 

development. Several dating methods were employed 

in this study, including correlation with dated deposits 

in West Yellowstone, Mont., tephrochronology of two 

ash sites, calculation of incision rates, and comparison 

to the marine oxygen-isotope record. The ages of the 

Pinedale, Bull Lake, Lower Roberts, and Mesa terraces 

are discussed first because these ages are most closely 

constrained. From these ages, incision rates are 

calculated in order to estimate the ages of the 

Holocene, Boyd, and Upper Roberts terraces.

Soil formation commences on fluvial deposits 

when the depositing river begins to incise. The Rock 

Creek terraces are composed of glaciofluvial gravel 

deposited at progressively lower altitudes during 

successive montane glaciations. It follows that the 

minimum time since the commencement of soil 

formation on a terrace is the time at which the 

succeeding interglaciation ends. By that time, the 

river must have cut down to a lower level at which it 

will deposit the next younger out wash. By analogy to 

the Pinedale glaciation, however, the most likely time 

for commencement of soil formation on a particular 

terrace is close to the end of the glacial advance that 

deposits the terrace gravel, rather than at the end of 

the following interglacial (discussed below).

Age of the Pinedale terrace

Ritter (1967) correlated the lowest major terrace 

deposit of Rock Creek (not counting the Holocene 

deposits) and its associated moraines with the Pinedale 

glacial advance based on moraine morphology; the 

moraines are sharp-crested, bouldery, and have many 

undrained depressions. Pierce and others (1976) used 

obsidian hydration rates to obtain an age of 30 ka for 

the Pinedale terminal moraine in West Yellowstone, 

with younger recessional deposits dating between 10 

and 15 ka.

The Pinedale terrace along Rock Creek stands 8 

to 15 m above the modern stream (table 4). This 

incision must have occurred some time ago, given the 

profile depth, color, and clay content of the soils on 

the Pinedale terrace. Moreover, younger Holocene fill 

terraces now 3 to 5 m above Rock Creek have been 

formed and incised since the Pinedale terrace was

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana Dll
Table 4. Stratigraphic units and ages of the Rock 

Creek soil chronosequence

(lea)

Height

w

(ka) Roberts

7 (2-10) 7 3.3±0.9 5.4±1.5 Post-last glaciatlu 

20 (10-30) 7.8±1.6 15.0±3.0 Correlated with dat

West Yellowstone

200 

295 l

347* 

410 4 

4404

Upper 

Robert!

610-

770 1 

870^ 

950^ 

1095] 

1950- 

2010 f

415 (295-515) ' 26.5±5.6 64.7±7.6 Younger than Lower

Roberts terrace, olde 

than Bull Lake terrac

600 (541-610) 47.8±4.5 88.1±4.4 Lava Creek A and B ashe

mark end of fluvial 

deposition

945 (770-950) ' 64.6±4.8 128.9±8.0 Younger than Mesa

Lower Roberts terrace

2000 (1950-2010) 125.3*5.1 252.3±10.5 Huckleberry Ridge ash

marks end of fluvial 

deposition

abandoned. Major deglaciation occurred in the Rocky 

Mountains by 14 ka (Porter and others, 1983). Hence, 

the Pinedale terrace was probably incised and soil 

formation commenced within 10 ka after the glacial 

outwash was deposited. This number will be used in 

the following discussions to approximate the time of 

incision of other terraces.

Soils on the Pinedale terrace of Rock Creek were 

sampled on the highest of several terrace levels, 

which probably corresponds with the maximum glacial 

advance. By analogy to West Yellowstone, the highest 

Pinedale surface was probably abandoned by the river 

sometime after 30 ka. I assign an age of 20 ka to this 

surface and the soils on it, but they could be as young 

as 10 ka or as old as 30 ka (table 4).

Age of the Bull Lake terrace

Ritter (1967) correlated the next higher terrace 

deposit and moraines with the Bull Lake glaciation. 

These moraines (fig. 2) have rounded crests, fewer 

surface boulders than Pinedale moraines, and few 

undrained depressions. Pierce and others (1976) and 

Pierce (1979) obtained ages ranging from 130 to 150 ka 

on obsidian in Bull Lake moraines of West 

Yellowstone. Whether all Bull Lake moraines in the 

Rocky Mountains predate the last interglacial is

The number of Pinedale terrace levels changes 

from three or more to one going downstream.

D12 Soil Chronosequences in the Western United States

debatable, but the assumption seems reasonable for 

Rock Creek deposits in part because of their proximity 

to the dated Yellowstone deposits. Moreover, the 

assumption can be checked by calculating the age of 

the Bull Lake terrace from incision rates derived from 

other terraces (discussed below).

The Bull Lake terrace surface was probably 

abandoned sometime after 130 ka; thus, this terrace 

and its soils are assigned an age of 120 ka (table 4). 

The terrace is probably no older than 150 ka if the 

correlation with Bull Lake deposits in West 

Yellowstone is correct. The Bull Lake terrace deposits 

are glaciofluvial and the terrace probably was 

stabilized during the following interglacial period. 

Therefore, the Bull Lake terrace is probably no 

younger than the end of the interglacial oxygenisotope stage 5, or about 75 ka (Shackleton and 

Opdyke, 1976).

Age of the Lower Roberts terrace

The Lower Roberts terrace and soils are dated at 

about 600 ka (table 4), because the uppermost fluvial 

deposits in this terrace include lenticular beds of the 

Lava Creek A and B ashes (ash site, fig. 2; identified 

by R. Wilcox, oral commun., 1983). The thin buried 

soil between the ashes and the coarse gravel suggests a 

short depositional hiatus of perhaps 5,000 years. The 

intervening sediments and the ash itself are both 

fluvial deposits, and the ashes can have been reworked 

little, because discrete beds of the two closely spaced 

Lava Creek A and B eruptions are preserved. Thus, 

the ashes must date the end of aggradation at 610 ka 

(Izett, 1981).

The Lower Roberts terrace surface was 

abandoned after deposition of the ashes. From the 

deep-sea oxygen isotope record, interglacial stage 15 

follows the Lava Creek eruption and ends at about 542 

ka (Shackleton and Opdyke, 1976). The Lower Roberts 

terrace and soils are probably no younger than this.

Age of the Mesa terrace

The age of the Mesa terrace (table 4) is inferred 

by a series of correlations with a terrace of the 

ancient Shoshone River east of Pryor Creek, about 40 

km west of the study area (figs. 1 and 6). The 

uppermost fluvial deposits of the Shoshone terrace 

above Pryor Creek consist of 2,010^a Huckleberry 

Ridge ash (Izett and Wilcox, 1982). This terrace can 

be traced nearly continuously to a point 295 m above 

the Yellowstone River, at which point the lithology of 

the terrace gravel indicates that it was deposited by 

the Yellowstone and Shoshone Rivers combined (Reheis 

and Agard, 1984). This terrace is correlated with two 

groups of Clarks Fork terrace remnants at similar 

heights above the Clarks Fork (fig. 6). One group is 

about 10 km east of Billings, and the other group, parts 

of which were called the Silesia gravel by Ritter 

(1975), lies east of the Clarks Fork-Rock Creek 

confluence. Ritter believed that the Silesia gravel is 

older than the Mesa terrace. However, the Silesia 

gravel and other nearby gravel deposits lie at the same 

height above the Clarks Fork and are correlated with
the last Mesa terrace remnant. This Mesa remnant 

represents the former confluence of the Clarks Fork 

and Rock Creek, judging from the lithology of sand 

grains in the terrace deposit.

The age of the Mesa terrace is about 2,000 ka, 

given the terrace correlation and allowing about 

10,000 years for the terrace surface to be abandoned 

after deposition of the Huckleberry Ridge ash. 

Oxygen-isotope ratios of a core from the Atlantic 

Ocean indicate that the end of a warm period 

following the ash eruption occurred at about 1,950 ka 

(van Donk, 1976). If the Mesa terrace deposits are 

glacial outwash, then the terrace was probably 

abandoned no later than the end of the ensuing 

interglacial, or about 1,950 ka (table 4).

Ages of remaining terraces from incision rates

Ages for the Pinedale, Lower Roberts, and Mesa 

terraces are used to suggest tentative ages of the 

remaining terraces (fig. 7 and table 4). The means and 

standard deviations of heights above present river 

level of three dated terraces (Pinedale, Lower 

Roberts, and Mesa) are plotted against their estimated 

ages. The dashed lines connecting these points and the 

origin give average stream-incision rates of 11.7 and 

5.5 cm/ka from 2,000 to 600 ka, 12.6 and 6.9 cm/ka 

from 600 to 20 ka, and 75 and 39 cm/ka from 20 ka to 

the present, for the Clarks Fork and Rock Creek 

respectively. The approximate ages of the Holocene, 

Bull Lake, Boyd, and Upper Roberts terraces are 

calculated from these incision rates and the means and

standard deviations of terrace heights above the river 

(method of Palmquist, 1979 and 1983). These heights 

were determined from topographic maps at several 

places (from four to eight, depending on the number of 

terrace remnants preserved). The standard deviations 

of the heights are large because they include errors 

due to measurement, erosion, and sideslope 

deposition. The terrace ages are: Holocene, 7 ± 2 ka; 

Bull Lake, 140 ± 15 ka; Boyd, 415 ± 60 ka; Upper 

Roberts, 945 ± 70 ka. These are minimum age errors 

because they only include uncertainties in the undated 

terrace heights.

The maximum age errors also include 

uncertainties in the heights and ages of the dated 

terraces. The error envelope (fig. 7) permits 

estimation of the maximum errors on the ages of the 

undated terraces. These errors are: Holocene, 7 _g 

ka; Bull Lake, 140 *|J ka; Boyd, 415 _JJf ka; Upper 

Roberts, 945 */|£ ka.

Terrace "heights were measured in two different 

areas in order to check the precision of this method: 

(1) a 20-km reach of the Clarks Fork from Elbow 

Creek north, and (2) a 15-km reach of Rock Creek 

from Roberts north (fig. 2). The ages estimated for 

undated terraces in the two areas are comparable (fig. 

7), but the age ranges estimated from the standard 

deviation of terrace heights are much larger for the 

Rock Creek reach because the rate of downcutting in 

that area is half the rate of the Clarks Fork.

The age of the Holocene terrace cannot be 

evaluated in detail. This terrace consists of a number 

of levels which could be earliest Holocene to modern 

in age. However, it is probable that the Holocene

DISTANCE, IN MILES 

20 30 40

1300

1200

- 1100

1000

900

Mesa S.G. 

M- - -J ,

H.R. ash

H

Junction

Rock 

- Creek

Junction Clarks Fork 

and Yellowstone Billings

4000

3500

3000

10 20 30 40 

DISTANCE, IN KILOMETERS

50 60

Figure 6. Comparison of Mesa and proposed equivalent 

terrace gradients to modern river gradients. H.R. ash, 

Huckleberry Ridge ash site; S.G., Silesia gravel 

(Ritter, 1975). Solid lines ending with vertical bars are

actual terrace remnants; dash and dash-dot lines are 

inferred correlations. Terraces on dashed line 

projected to Clarks Fork and Yellowstone Rivers; 

those on dash-dot line projected to Pry or Creek.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D13
deposits are not older than 10 ka (table 4), which is the 

age of the youngest deglacial deposits in West 

Yellowstone (Pierce and others, 1976).

The incision-rate age of 140 ka for the Bull Lake

terrace confirms the correlation with Bull Lake 

deposits in West Yellowstone. The minimum incisionrate age of 90 ka falls within the time span of 

interglacial stage 5 (Shackleton and Opdyke, 1976), and

250 20

200

150

100

50

Correlation to 

West Yellowstone

Huckleberry 

Ridge ash

200 400 600 800 1000 1200

AGE, IN YEARS (x103)

1400 1600 1800 2000

Figure 7. Graphs estimating ages of the Holocene (H), 

Bull Lake (BL), Boyd (B), and Upper Roberts (UR) 

terraces from mean terrace heights above the Clarks 

Fork and Rock Creek and ages of the Pinedale (P), 

Lower Roberts (LR), and Mesa (M) terraces. Dashed 

line is incision rate. Boxes around points for the 

Pinedale, Lower Roberts, and Mesa terraces show 

error limits of age from table 4 (horizontal lines) and

height (± 1 standard deviation, vertical lines). Lines 

connecting outermost points of the boxes show the 

error envelope. Parallelograms show the age errors 

for other terraces, derived by projecting their height 

errors (± 1 standard deviation) horizontally to meet the 

lines of the error envelope (method adapted from 

Palmquist, 1979, 1983).

D14 Soil Chronosequences in the Western United States
the maximum age of 200 ka is within the time span of 

glacial stage 6. The best estimate age (table 4) of 120 

ka for the Bull Lake terrace assumes that the terrace 

was incised within 10 ka after glacial activity ceased 

(130 ka in West Yellowstone).

The Boyd terrace is dated at about 415 ka from 

the Clarks Fork incision rate (fig. 7) and could range 

from 295 to 515 ka. Within this time span, Shackleton 

and Opdyke (1976) reported two glacial stages in the 

oxygen-isotope record from Pacific cores: stage 10 

ends at about 347 ka, and stage 12 ends at about 440 

ka (table 4). Using a core from the Atlantic and 

different calibration methods, van Donk (1976) found 

four glacial stages terminating within the timespan in 

question: stage 10 at about 300 ka, stage 12 at 360 ka, 

stage 14 at 400 ka, and stage 16 at 500 ka. Which 

glacial stage may correspond to the local glaciation 

that produced the Boyd outwash is unknown, and the 

age range given in table 4 cannot be narrowed.

The incision-rate age of the Upper Roberts 

terrace is 945 ka, and the range is 770 to 1,095 ka. 

The range is large because the terrace surfaces are 

poorly preserved. Van Donk (1976) showed three 

glacial stages in the Atlantic core that end within this 

timespan: stage 22 at about 780 ka, stage 24 at 870 

ka, and stage 26 at 950 ka. The maximum incisionrate age of 1,095 ka falls within the very long 

interglacial stage 27, so the Upper Roberts terrace 

probably corresponds to a younger glacial stage. The 

oxygen-isotope record in this timespan is closely 

calibrated by the Jaramillo reverse-magnetization 

episode. Hence, the maximum age of the Upper 

Roberts is probably 950 ka (the end of glacial stage 

26), and this coincides with the best estimate age of 

945 ka from the incision rate.

The incision-rate method involves one major 

assumption: The long-term incision rate has remained 

constant between age control points. In the short 

term, this is false, because terraces are formed during 

stable or aggrading fluvial conditions and isolated by 

later incision. For example, the post-Pinedale incision 

rate (fig. 7) is six times faster than the pre-Pinedale, 

long-term incision rates.

Correlations of terraces were based on 

stratigraphy, terrace gradients, and heights above 

modern stream level. The terraces are generally well 

preserved, and these correlations are confidently made 

with the following exceptions: (1) The Lower Roberts 

terrace near Red Lodge may possibly be Upper 

Roberts, because the Upper Roberts terrace diverges 

from the Lower Roberts downstream and is not 

preserved upstream from the town of Roberts. (2) 

Soil RC-6 (fig. 2), which was sampled where the 

gradients of the Upper and Lower Roberts terraces 

converge, may be located on the Lower Roberts 

terrace rather than the Upper Roberts. (3) The Boyd 

terrace is absent between Roberts and Red Lodge, so 

the identity of that terrace at Red Lodge cannot be 

proved.

SOIL CLASSIFICATION

Soil morphology is commonly described with 

reference to the U.S. soil classification system (Soil 

Survey Staff, 1975). Unfortunately, soils of various

ages within each chronosequence differ little when 

classified. All of the soils, except the youngest ones 

developed on Holocene deposits, have argillic horizons, 

and the basin soils and many transition soils have 

calcic horizons. However, none of the soils have 

horizons with sufficient clay or CaCOg to qualify them 

as very old soils (the prefix pale- indicates age) in the 

present taxonomy. The soil classification is more 

successful in indicating climatic differences between 

different chronosequences. Soil classifications that 

follow differ from those in the published soil survey 

for Carbon County, Mont. (Soil Conservation Service, 

1975), primarily because data from the soil 

temperature probes (table 2) indicate that the 

transition soils and probably the mountain-front soils 

are presently under a rnesic rather than a cryic soil 

temperature regime.

Soils in the mountain-front chronosequence are 

difficult to classify because the moisture regime 

borders on the udic and ustic, and the temperature 

regime borders on the cryic and mesic. These soils all 

have mollic epipedons (typical of soils developed under 

grass); under the present ustic moisture and mesic 

temperature regimes, the soils classify as Udic 

Argiustolls, with the exception of the Holocene soil 

which lacks an argiliic horizon and is a Udorthentic 

Haplustoll.

Transition soils all have mollic epipedons and are 

under ustic moisture and mesic temperature regimes. 

Holocene soils lack argillic or calcic horizons and 

classify as Udic Haplustolls. Older soils have argillic 

horizons; depending on whether or not they also 

possess calcic horizons (variable in the transition 

zone), they are Udic Argiustolls (no calcic horizon) or 

Typic Argiustolls.

Basin soils all possess mollic and calcic horizons; 

most have argillic horizons, with the exception of the 

Holocene soils. Under the modern aridic and mesic 

regimes, the Holocene soils are Typic Calciorthids. 

The older soils are classified as Ustollic Haplargids 

with the exception of the Mesa soils. The height of 

the terrace remnant on which the Mesa soils were 

sampled may cause them to have a somewhat moister 

climate, although no site-specific climatic data are 

available. Thus, these soils may be Typic Argiustolls, 

like some of the transition soils.

The U.S. Soil Taxonomy does not adequately 

describe the Rock Creek soils under the reconstructed 

glacial climate (table 2). The mountain-front, 

transition, and basin areas would have had a pergelic 

temperature regime. The soil taxonomy has no 

provision for pergelic mollisols with argillic or calcic 

horizons.

CHRONOLOGIC DEVELOPMENT OF SOILS

Field properties of the Rock Creek soils change 

with increasing age (supplementary table 1). The 

thickness of A and B horizons and silt and clay 

contents increase with age. Colors redden and 

brighten or whiten and pale with time. Pedogenic 

CaCOg increases in basin soils. Soil structure does not 

show consistent changes with time, apparently because 

of the gravelly nature of the parent material. These 

and other trends are studied by converting verbal

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D15
descriptions of soil properties to numerical quantities 

using Harden's (1982b) soil development index.

The vertical distribution of index properties in 

soil profiles shows patterns of soil development with 

time in different climates (figs. 8 and 9). Textural 

fining due to accumulation of silt and clay (total 

texture) increases in amount and depth in the profiles 

with time in all three chronosequences, but the fines 

are concentrated at lesser depths in drier climates. 

Rubification (reddening and brightening) increases in 

amount and depth with age in mountain-front soils. In 

contrast, the colors of calcareous horizons of basin and 

transition soils pale and lighten (Harden and Taylor, 

1983). Values for pH decrease in mountain-front soils, 

but increase at depth in drier soils. The profile index, 

which weights all component properties equally , 

shows that most development of soil properties is 

concentrated in the A and B horizons.

This study extrapolates or limits all soil depths 

to 250 cm when calculating property values using the 

Harden (1982b) index, in order to minimize the 

variability caused by different sampling depths in the 

different excavations. Index values summed over the 

profiles of young soils may be too large, because 

values in the lowest horizon sampled (often 100-150 

cm) are extrapolated to 250 cm. In particular, the 

rubification values for the Holocene and post-Pinedale 

mountain-front soils are probably too large, as is one 

pH value (post-Pinedale soil RC-15, fig. 2). However, 

changes in color and in pH extend to the bottom of 

older soils; hence, profile sums for the color and pH 

indices may be minimum values for development in 

older soils.

The rate of development of index properties 

varies in different climates when the best estimate 

surface ages in table 4 are used. Unless specifically 

mentioned as omitted, all soils listed in supplementary 

table 1 are included in the regression equations. 

Figures in the following discussion display values 

considered to be anomalously large, but employ the 

probable minimum values in regression equations. The 

significance levels of£ (coefficient of determination) 

values are determined from tabled values for F ratios 

at specified degrees of freedom, which varies 

depending on N, the number of samples used in each 

regression (Davis, 1973).

Mountain-Front Soils

Several soil properties (Harden, 1982b) change 

with time in mountain-front soils, including 

rubification (reddening and brightening due to iron 

oxide formation), melanization (darkening due to 

accumulation of organic matter), pH lowering, clay 

films, and total texture (changes in silt and clay 

content as reflected in texture, corrected with 

laboratory data, plus wet consistence). Values for the 

post-Mesa soil RC-28 (fig. 2) have been omitted from 

regression calculations because it appears to have been 

affected by erosion.

Only selected component properties of the profile 

index are shown on figures 8 and 9.

The individual soil properties and the profile 

index (Harden, 1982b) calculated from the combined 

properties generally show logarithmic (log) rates of 

increase with time (fig. 10). Regressions of 

melanization, total texture, rubification, clay films, 

and the profile index with the best estimate soil ages 

(table 4) are significant at the 1 percent level of 

confidence; pH lowering with time is irregular and is 

not significant at the 5 percent level. Rubification, 

total texture, and clay films are related to nearsurface weathering phenomena, and they are largest in 

B horizons (fig. 8). Melanization and pH lowering are 

related to accumulation of organic matter, so they are 

largest in A and upper B horizons (fig. 9).

Petrographic thin sections indicate that silt and 

clay accumulate by both translocation and weathering 

in situ in the mountain-front soils. Oriented argillans 

of clay on sand grains (Morozova, 1964; Dumanski, 

1969) are deposited by percolating water; they show 

translocation of clay particles in the Rock Creek soils 

(fig. 11), and they increase in thickness and abundance 

with time through soils on the Bull Lake terrace (120 

ka). Older soils have thicker but less well oriented 

argillans and other masses of clay in the matrix, 

indicating that translocated clays and other particles 

weather in situ with time.

The logarithmic property-time relations (fig. 10) 

indicate that initial weathering is rapid in mountainfront soils. Stones weather to grus quickly; even postPinedale soils have 10-15 percent grusified clasts in 

the B horizon. The rapid disintegration may be due to 

hydration and expansion of biotite grains (Wahrhaftig, 

1965). In petrographic thin sections, expanded biotite 

flakes occur in soils as young as 20 ka. Concomitant 

release and oxidation of iron from the biotite probably 

accounts for the rapid rubification of the soils, with 

hues reaching 7.5 YR and chromas of 6 in postPinedale soils. Only the post-Mesa soil and the postBull Lake soil have redder hues.

Basin Soils

Different soil properties change with time for 

soils forming in the semiarid climate in the basin (figs. 

8 and 9). Values of pH decrease near the surface 

where organic matter is concentrated, but increase at 

depth (fig. 9) due to the presence of CaCO3 (abrasion 

pH of CaCO3 is 8.0; Stevens and Carron, 1948). Total 

texture increases with time, but clay films do not 

develop in the basin soils. Although thin sections show 

that clay translocation has occurred (see fig. 20),

Figure 8. Rubification (mountain-front soils), color 

paling and color lightening (transition and basin soils), 

and total-texture (all soils) indices (Harden, 1982b, and 

Harden and Taylor, 1983) for selected soils on Rock 

Creek, showing changes with depth, time, and 

climate. Numbers indicate soil profiles (see 

supplementary tables 1 and 2). Dashed lines show 

boundaries between soil horizons A, B, and C. K 

horizons are included with B horizons in some 

transition and basin soils. See figure 2 for location of 

soil profiles.

D16 Soil Chronosequences in the Western United States
HARDEN INDEX VALUE

Holocene Pinedale , V

0 0.5 0 0.5 0

Q 1 1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 A III

1 -

2 -

L

A

C

-

-x- "

;! _ D ,p B

J c -

( .

RC-21

RC-38

'V;

--,

!

0.5

i i i i

l r

;

B

_ , Lower 

B°Yd Roberts

0 0.5 0

i i i i i i i i i iii

-

-

RC-31

"L1T-6

r

I

'

B

-

!

.-.._)

0.5

i

i

* 1

" " "*

Upper -_ 

Roberts Mesa

0 0.5

iii i i i i i i i i i

A

C

UT , A

% ' - 

i B

Ic"

RC-14

C RC-16

0.5 0.5 0.5

RC-30

0.5 0.5 0.5

-

1 -

T _A

I 1 D

J

C

RC-40

-

f";

L L....J B

J

C

pr* oo

ij.-_ -......, A

! Q

C

RC-41

i1 - ........ A

1"i B

r J, 

C

-

:L., A

\ l"] B

1

. C

RC-34

_J '.... ... -M

_, B L ""I,

1 ; -

\

\

r

RC-36

,

1

i

""""I. A

........I

;

;

C 

RC-33

0 0.5 0.5 0.5

RC-37

0.5 0.5 0.5 0.5

u -

1 -

2 -

-

"ir j A

J;

C 

RC-46B

-

I..., A

,.... .. B

C 

RC-20

-

J---------t-- rt

C

RC-27

-

-

J__ L.. ....,_ rt

:

i

C

-

RC-23

^------^^

 -'

C

r1 i___.. t

L - E

!

I 1 r1 '

RC-25

-

RC-24

L L. .......

i R

: "

;

C

1

EXPLANATION RC-26A

 Color

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D17
DEPTH, IN METERS

O

O D3

m 

X

TJ

 a T3 -D 2 

II3Z

= Q. ±! >

Q 8 5- H

o 03

l___

3D !

0 !

ro

___j=;

'

0

=tf

CD

30

O _ _ _ . __ ........

ro

I U_i L 1 ^ u.

j LJ-H*

 ... J | L

1 1 n | CD [

i i

I.I I

---» 1 r ,

0

1

tl 1 r ^=O

03 1

1

i

n

Basin Transition zone 
macroscopic clay films on ped faces are not well 

preserved. Accumulation of pedogenic CaCO3 causes 

soils to pale and lighten with time (Harden and Taylor, 

1983). If iron oxidation is occurring in the basin soils, 

it is masked by CaCO3 ; as a result, rubification does 

not increase with time. Melanization does not 

increase because organic matter is rapidly oxidized in 

a dry climate.

The profile index and the properties of total 

texture, color paling and color lightening, and pH 

increase with time; the regressions are significant at 

the 1 percent level of confidence (fig. 12). Values for 

the post-Mesa soil RC-26B (fig. 2) were omitted 

because this soil appears eroded. In addition, the postPinedale soil RC-20 has an anomalously high value of 

pH increase and consequently a high value for the 

profile index (fig. 12B), possibly caused by local 

irrigation. Values for this soil were omitted from the 

pH and profile index regressions.

The regressions with age of the-indices for pH 

increase and texture, and the profile index, appear to 

be equally good with either log or linear time (fig. 

12). In general, the log solutions tend to overestimate 

values of these indices for soils in the 10 -10 -year 

age range and to underestimate values for the postMesa soils. The linear solutions fit the property values 

of the soils older than 10 years well, but overestimate 

property values for the younger soils. Assuming that 

the best estimate soil ages are correct, basin soils may 

initially develop at log rates, but later develop at 

linear rates.

Color paling and color lightening are clearly best 

explained by a linear time function (fig. 12A). This 

property reflects accumulation of CaCO3 and is better 

related to soil age than is the quantity of pedogenic 

CaCO3 . Profile weights of pedogenic CaCOo (fig. 13) 

increase with age of basin soils up to about 400 ka, but 

the relationship is not significant for older soils.

Eolian contributions of calcareous dust are 

important in the development of basin soils. The 

increase in total texture with time may be due at least 

in part to additions of eolian silt (supplementary tables 

1 and 2). The A and B horizons of most basin soils are 

loams or silt loams rather than sandy loams or sandy 

clay loams characteristic of mountain soils. 

Formation of calcic soils in noncalcareous parent 

materials is commonly attributed to atmospheric 

additions of CaCO3 , including calcareous dust and 

Ca contained in precipitation (for example Gardner, 

1972; Bachman and Machette, 1977; Gile and 

Grossman, 1979; Machette, 1985). Because the Rock 

Creek alluvium contains almost no calcareous detritus, 

accumulation of CaCO3 in the soils with time must 

result from atmospheric additions.

The composition and amount of dust collected 

for one year in a trap near Joliet (fig. 2) suggests that

Figure 9. Profile and pH indices (adapted from 

Harden, 1982b) for selected soils on Rock Creek, 

showing changes with depth, time, and climate. 

Numbers indicate soil profiles (see supplementary 

tables 1 and 2). Dashed lines show major boundaries 

between soil horizons A, B, and C. K horizons are 

included with B horizons in some transition and basin 

soils. See figure 2 for location of soil profiles.

there are significant additions of calcareous eolian 

dust to the semiarid Rock Creek soils (table 5). Infall 

of mineral particles (nonsalt, nonorganic fraction) is 

about 15x10 g/cm -yr. Even if the measured amount 

was 10 times the amount away from plowed fields, this 

input would be significant. CaCO3 is added at the rate 

of 0.3xlO~4 g/crn^-yr. This CaCO3 rate is an order of 

magnitude less than modern dust fall rates near Las 

Cruces, N. Mex. (Gile and Grossman, 1979), the 

Holocene rate calculated for southern California 

(McFadden and Tinsley, 1985), and the Pleistocene rate

120

80

40

TERRACE 

BL B LR UR M

Property Regressions:

N r2 Significance 

A Melanization 9 0.67 <0.01 

 Total texture 9 0.72 < 0.01 

X pH lowering 9 None at 0.05

120

80

40

LOG YEARS

TERRACE 

BL B LR UR

Property Regressions:

N r2 Significance

A Profile index 9 0.86 < 0.01

 Rubification 9 0.57 < 0.025

(minimum value) 0.75 <0.01

X Clay films 9 0.86 < 0.01

LOG YEARS

Figure 10. Relation of age of mountain-front soils to 

A, melanization, pH lowering, and total texture; and 

B, profile index, rubification, and clay films (Harden, 

1982a). Straight lines are regressions on log age (table 

4). Circled data points represent questionable values 

derived by large extrapolations to 250 cm depth; 

arrows extend down to minimum index values for these 

points. H, Holocene; P, Pinedale; BL, Bull Lake; B, 

Boyd; LR, Lower Roberts; UR, Upper Roberts; M, 

?,flesa; N, number of data points.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D19
calculated for areas of Utah and New Mexico 

(Machette, 1985). Lower rates at Joliet are probably 

due to the lack of extensive calcareous deposits 

upwind to the west and north.

Rates of accumulation of CaCOg in basin soils, 

calculated from profile weights of CaCOo (fig. 13 and 

supplementary table 7), range from O.llto 1.5x10 

g/cm -'yr for soils older than 400 ka, to 1.0 to 

5.5x10 4 g/cm -yr for post-Holocene and post-Pinedale 

soils. The lower rates for older soils probably reflect 

episodes of CaCO3 solution during glaciations. The 

higher rates calculated for the younger soils represent 

the average rate of accumulation during the drier 

Holocene period (note that the amount of pedogenic 

CaCOo is similar for post-Holocene and post-Pinedale 

soils, fig. 13). This disparity between rates of CaCO3 

accumulation for older and younger soils is similar to 

that found by Machette (1985) in New Mexico and 

Utah.

Figure 11. Photomicrographs (crossed nicols) of 

argillans coating grains in mountain-front soils. A, 

Post-Pinedale soil has thin discontinuous argillans, best 

seen in bright bands (arrows) around large gray quartz 

grain in left center. B, Post-Boyd soil has thicker, 

continuous argillans (arrows).

Linear development rates for the older basin 

soils are contrary to results obtained by workers in 

warmer, more moist climates (Harden, 1982a and b; 

Colman and Pierce, 1981; Birkeland, 1984, p. 204 and 

225), where rates were found to be logarithmic or 

exponential. Bockheim (1980) obtained logarithmic 

trends with time for soils formed in climates ranging 

from tropical rainy to cold desert; his study, however, 

used maximum values in each profile, rather than 

summations over the total profile depth. Muhs (1982) 

expressed soil properties in an arid xeric climate as 

profile summations and found linear trends with time; 

these soils probably received considerable dust influx. 

I believe that linear trends with soil age of index

120

80

TERRACE 

BL B LR UR M

Property Regressions:

N r2 Significance

 Total texture 10

log 0.90 <0.01 

linear 0.90 <0.01

X Color paling 10 0.68 <0.01 

and lightening

~ 120

80

40

B LR UR M

Property Regressions:

N r2 Significance

 Profile index

log 9 0.81 <0.01 

linear 9 0.85 < 0.01

X pH increase

log 9 0.68 <0.01 

linear 9 0.68 < 0.01

B

LOG YEARS

Figure 12. Relation of age of basin soils to A, total 

texture and color paling and color lightening; and B, 

profile index and pH increase (adapted from Harden, 

1982a, and Harden and Taylor, 1983). Straight line is 

regression on log age; curved lines are regressions on 

age (table 4). Circled data points represent 

questionable values. H, Holocene; P, Pinedale; BL, 

Bull Lake; B, Boyd; LR, Lower Roberts; UR, Upper 

Roberts; M, Mesa; N, number of data points.

D20 Soil Chronosequences in the Western United States
values based on field criteria for the basin soils of 

Rock Creek may best be explained, not by weathering 

phenomena, but by cumulative additions from 

atmospheric sources to the soil profiles.

Table 5. Composition and particle size of eolian dust 

from dust trap

[First column under major oxides gives percent as measured on the nonsalt 

silt-plus-clay fraction. Second column gives recalculated percent oxides 

assuming that all CaCOo in the trap was contained in the silt-plus-clay 

fraction. See figure 2 for sample location]

Transition Soils

Transition soils have time-dependent properties 

that are most similar to those of basin soils. Soils on 

the older terraces of the transition chronosequence are 

located within 15 km of the mountain front (fig. 2), yet 

there are no significant trends of rubification, 

melanization, and clay films with time in these soils.

The profile index and the properties of total 

texture, pH, and color paling and color lightening 

increase with time (fig. 14). Data for the post-Mesa 

soil RC-8, located on the eroding end of a terrace 

remnant, has not been included in the regression 

calculations. Soil RC-32 was sampled at the edge of a 

lawn and appears anomalously well developed because 

of irrigation and fertilization; it was also omitted. 

The rates of property development are similar to those 

of basin soils (compare figs. 12 and 14). Values of r£ 

for pH, total texture, and the profile index are 

significant at the 1 percent level of confidence. 

Color paling and color lightening and profile weight of 

pedogenic CaCOjj (fig. 13) are not as well related to 

time as they are in basin soils, as would be expected in 

soils that have undergone periodic precipitation and 

dissolution of secondary CaCO3 .

Values of pH appear to reflect a transitional 

state between mountain-front and basin soils (figs. 9

TERRACE

40

30

^ 20

111

O 

O 

O

10

BL B LR UR M -i r i r

Property: 

X Transition soils 

A Basin soils

N=10 

N=13

X

X X

X

A 

XX

LOG YEARS

Figure 13. Relation of ages (table 4) of basin and 

transition soils to profile weights of pedogenic CaCOo 

(in grams per square centimeter in 250 cm of soil). H, 

Holocene; P, Pinedale; BL, Bull Lake; B, Boyd; LR, 

Lower Roberts; UR, Upper Roberts; M, Mesa; N, 

number of data points.

Air-dry weight (g) 

Percent of total sample 

organics ------ 

mineral matter 

Percent of mineral matter

Flux rate (10~4g/cm2 /yr) 

mineral matter 

CaCO, 

1

19

79

fr

15

.7047

.0

.5 

action

.6 

.3

Percent of silt-plusOxide Measured

Si02 56 

M2°3 11>9

MgO 1.5 

CaO 1.6 

Na2 0 3.1

Zr02 .035

clay fraction 

Recalculated

55 

11.7

1.5 

1.6 

3.1

.034

120

80

40

TERRACE 

BL B LR UR M

t 120

Property Regressions:

N r2 Significance 

 Total texture 12 0.74 <0.01 

XpH increase 12 0.71 <0.01

LOG YEARS

TERRACE 

BL B LR UR M

80

40

Property Regressions:

N r2 Significance

 Profile index

log 12 0.77 <0.01 

linear 12 0.77 <0.01

X Color paling 12 0.46 <0.025 

and lightening

'X Color paling | ^ andli9hte' B

LOG YEARS

Figure 14. Relation of age of transition soils to A, 

total texture and pH increase; and B, profile index and 

color paling and color lightening (adapted from 

Harden, 1982a, and Harden and Taylor, 1983). Straight 

lines are regressions on log age; curved lines are 

regressions on age (table 4). H, Holocene; P, Pinedale; 

BL, Bull Lake; B, Boyd; LR, Lower Roberts; UR, Upper 

Roberts; M, Mesa; N, number of data points.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D21
and 14A). Values of pH increase with time in the 

lower soil horizons, similar to pH trends in the basin 

soils. However, pH decreases with age in the upper 

horizons of transition soils, similar to pH in mountainfront soils.

The profile index for transition soils develops at 

a rate comparable to that for basin soils (figs. 12B and 

14B), and values for the two groups (77 for transition 

and 72 for basin) are about the same for the oldest 

post-Mesa soils. As for basin soils, the relation of the 

profile index to estimated soil age is equally well 

expressed as a log or a linear function. The linear 

function appears to fit the profile-index values better 

than the log function, except that the linear function 

overestimates values for the Holocene soils.

The similarity between (1) the types of 

properties that have significant relations to time and 

(2) the development rates for transition and basin soils 

suggests that development of transition soils is 

controlled by the same processes that affect basin 

soils: eolian additions of CaCOg and dust. If this is 

so, the amount of eolian material added through time 

may be similar in both chronosequences. Although 

CaCOg is flushed periodically from the transition soils, 

the pH increase related to the additions of CaCOo 

appears less affected by flushing. The additions of silt 

and clay from eolian dust are not affected by climatic 

changes.

Chronologic Summary

Six of the seven soil properties examined 

consistently correlate with age of the soils. Only pHlowering of mountain-front soils does not have a 

statistically significant relationship with time. 

Change in pH is caused by very different processes in 

each chronosequence: pH lowering due to organic 

matter accumulation in mountain-front and transition 

soils, versus pH increase due to accumulation of 

pedogenic CaCOg in basin and transition soils. Total 

texture and color changes are also controlled by 

different processes in different climatic regimes. The 

texture of mountain-front soils fines at log rates, 

probably controlled by near-surface weathering 

processes, whereas textures of transition and basin 

soils older than 20 ka fine at linear rates, probably 

caused by influx of eolian dust. Modern dust and the 

increasing amounts of CaCO3 and silt in basin soils 

with time support cumulative additions from 

atmospheric sources. Log increases in rubification and 

melanization of mountain soils are related to 

weathering, but eolian CaCOg influx probably causes 

linear increases in color paling and color lightening.

These findings contrast with those of Harden and 

Taylor (1983). They found that rubification, dry or 

moist consistence, and total texture increased at log 

rates for soils in udic, xeric, and aridic moisture 

regimes, although texture (their fig. 4A) appears to 

exhibit more of a linear trend with time. Regression 

coefficients for linear time were not given in their 

study. In this study, rubification does not correlate 

with time for semiarid soils, and texture in these soils 

appears better related to linear than to log time. 

Perhaps rubification does not develop in Rock Creek 

basin soils because the climate there is cool and

semiarid, rather than hot and semiarid as in the Las 

Cruces, N. Mex. area used in the Harden and Taylor 

study. Color paling and color lightening have strong 

relations with log time in their study, whereas these 

two properties combined correlated best with linear 

time in this study.

Harden and Taylor (1983) also showed that soils 

from udic, xeric, and aridic moisture regimes 

developed at similar rates when they were compared 

using profile indices calculated from the four best 

time-related properties in each chronosequence. 

There are both similarities and differences among 

profile indices of the three Rock Creek 

chronosequences (fig. 15). The logarithmic functions 

for the three chronosequences have similar slopes, 

although profile indices on the average are smaller for 

the transition and basin soils than for the mountainfront soils. Harden and Taylor (1983) also noted that 

aridic soils tended to develop at a similar rate but with 

lower values than soils in moister climates. The rates 

of development are similar enough that when profile 

indices for soils from all the chronosequences are 

regressed with soil ages, the r value of the log 

function is 0.71. However, when the Holocene soils of 

Rock Creek are omitted, the best-fit time functions 

for the drier soils are linear ones, and they are nearly 

identical for the basin and transition chronosequences.

In conclusion, although the profile index appears 

to develop at similar rates for the three Rock Creek 

chronosequences when regressed against log time, 

there are also important differences. Caution should 

be used in applying linear or log curves to weathering

80

60

O 40

TERRACE 

BL B LR UR

20

Chronosequence Regressions

N

 Mountain front 9 

X Transition zone 12 

log

linear

A Basin 9 

log 

linear 

All soils 30

0.86

0.77

0.77

Significance 

<0.01

LOG YEARS

Figure 15. Relation of age of the three soil 

chronosequences individually and as a group to profile 

index. Straight lines are regressions on log age; curved 

lines are regressions on age (table 4). Circled data 

point represents questionable value; arrow extends 

down to minimum index value for this point. H, 

Holocene; P, Pinedale; BL, Bull Lake; B, Boyd; LR, 

Lower Roberts; UR, Upper Roberts; M, Mesa; N, 

number of data points.

D22 Soil Chronosequences in the Western United States
data in order to estimate soil age. For example, 

Colman and Pierce (1981) assumed logarithmic rates of 

weathering-rind formation in order to estimate the 

ages of till deposits in the Western United States. 

Their arguments were well founded, but these 

arguments should not necessarily be extrapolated to 

soil-forming processes.

CLIMATIC DEVELOPMENT OF SOILS

Time-related properties of soils along Rock 

Creek are strongly influenced by the local climate. 

Different properties change with time in mountainfront (moist) and basin (semiarid) soils. The transition 

soils, rather than reflecting the combined attributes of 

mountain-front and basin climates, resemble the basin 

soils. Either the modern interglacial climate of the 

transition zone has eliminated morphologies that are 

characteristic of a glacial climate, or glacial climatic 

changes may not have altered greatly the style of soil 

formation along Rock Creek. If the changes had been 

effective, transition soils should display time-related 

characteristics of mountain-front soils, such as 

melanization and clay films, as well as characteristics 

of basin soils. Soil properties within each 

chronosequence can be used to examine the local 

effects of climatic change and to determine whether 

the reconstructed glacial climate is reasonable.

Mountain-Front Soils

Mountain-front soils on Rock Creek have 

developed under relatively moist, cool or cold climates 

(fig. 5). Under a glacial climate, the soil moisture 

regime probably changed from ustic to udic, and 

surplus water available for leaching and deep 

percolation probably doubled from 160 to 335 mm/yr 

(assuming that glacial precipitation was equal to the 

modern level). Actual leaching of the soil was most 

likely concentrated in the active zone above 

permafrost in months when soil temperatures were 

above freezing.

Depth of pedogenic clay is related to the depth 

of water movement in a soil, and may vary with 

climate (Rutter and others, 1978; Nettleton and 

others, 1975). Pedogenic clay depth (defined here as 

depth to top of first C horizon) can be related to 

climate and soil age by plotting clay depth in each soil 

on a diagram showing modern water movement at Red 

Lodge (fig. 16; method of Arkley, 1963). Clay depths 

are calculated in units of yearly water penetration 

based on the available water-holding capacity of each 

horizon, in order to equalize the effect of different 

soil textures on permeability. However, the increase 

of silt and clay in profiles with time can change clay 

depth. Fine-grained soils have greater water-holding 

capacity than do coarse sandy soils. Thus, pedogenic 

clay moved to a given wetting depth early in soil 

development may appear at greater wetting depths 

with time because of accumulation of fines near the 

surface.

Post-Pinedale and Holocene soils have clays at 

shallower wetting depths than do older soils (fig. 16). 

This difference is probably related to climate, because

depths do not continue to increase with age in the 

older soils. Post-Pinedale and Holocene soils have 

mainly formed under an interglacial climate, whereas 

older soils have formed during both dry interglacial 

and moist glacial periods. Greater depth of pedogenic 

clay in the post-Pinedale soil than in the Holocene soil 

may reflect the greater amount of fines accumulated 

near the surface of the older soil.

The similarity of pedogenic clay depths for older 

soils implies that pre-Pinedale glaciations were no 

more moist than the Pinedale glaciation, when clays 

were moved to a wetting depth of 10 cm (fig. 16). If 

older glaciations had been more moist, soils older than 

the post-Bull Lake soil would have pedogenic clay at 

wetting depths greater than 10 cm. Drier previous 

glaciations are possible, because high moisture levels 

during Pinedale time could have affected the position 

of pedogenic clay in all older soils. However, the 

greater extent of pre-Pinedale till deposits (fig. 2) 

suggests that these glaciations were probably not drier 

than the Pinedale glaciation.

WATER FLUX. IN CENTIMETERS PER YEAR 

10 20 60

Figure 16. Water movement and pedogenic features of 

mountain-front soils. Average yearly water movement 

(curved line) calculated for 82-year record at Red 

Lodge using Arkley's (1963) method. Pedogenic clay 

depth defined as base of B horizon and expressed in 

centimeters of wetting depth of yearly precipitation 

by estimating available water-holding capacity for 

each horizon from textural data (Salter and Williams, 

1967).

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D23
Transition Soils

Transition soils show abundant evidence of 

having formed under variable climate. Soils of drier 

climates that accumulate CaCOo typically have 

horizons of CaCO3 enrichment with smooth upper 

boundaries, reflecting the average depth of transport 

of CaCO3 in solution. CaCO3 horizons of transition 

soils always have wavy, irregular tops that suggest 

periodic dissolution of CaCO3 (fig. 17A). Near the 

boundary between calcic and noncalcic soils, pedogenic 

CaCO3 occurs in patches having a random-appearing 

distribution on continuously exposed faces in gravel 

pits. Locally, CaCO3 fills cracks in stones as it does 

in the more highly calcareous basin soils, suggesting a

Kfj- i^»H-.*- f^*te'- * '^\** ^ <H I ^fcr^' \ '" ' ^ " r"J v

VL- *-*-^ wit ., J: ^^Lslij'^^

-*-'»vSSJS K3> I" l*» 'if F"S" ' ~^\^

f -vw,»* -.-^S"*' -'

Figure 17. Evidence of periodic CaCO3 dissolution in 

transition soils. A, Wavy top of light-colored CaCO3 

horizon (dashed line) reflects dissolution of formerly 

horizontal upper boundary. Lens cap is 5 cm in 

diameter. B, Photomicrograph shows lenticular pebble 

coats (pc) of CaCO3 broken away from the pebbles and 

reworked into the soil matrix. New, finer grained 

CaCO3 (c) is precipitating in matrix around pebble 

coats.

formerly more extensive CaCO3 horizon. 

Petrographic thin sections of peds (fig. 17B) also 

reveal evidence of dissolution and reprecipitation of 

pedogenic CaCO3 . Unfortunately, the fluctuations of 

moisture in these soils were apparently sufficient to 

wipe out much of the evidence of older wet and dry 

cycles.

The position of the calcic-noncalcic soil 

boundary shifts mountainward with increasing terrace 

age up to the lower Roberts terrace (figs. 3 and 18). 

The Boyd and Upper Roberts terraces are not 

preserved in the critical area. The calcic-noncalcic 

soil boundary on the Boyd terrace was estimated from 

the appearance of soil RC-11 on the Boyd remnant 

with calcic soils nearest the mountains at the town of 

Roberts.

Several possible explanations for the shifting 

calcic-noncalcic soil boundary are based on differences 

in climate among the terraces: (1) If rainfall 

decreases away from the river bottom, older terraces 

that are farther from Rock Creek may show CaCO3 

closer to the mountain front. However, the calcicnoncalcic soil boundary on the Lower Roberts terrace 

occurs where the terrace is actually adjacent to the 

valley near Red Lodge. (2) Rainfall may decrease with 

increasing height above the creek. If that were so, the 

observed correspondence of the calcic-noncalcic soil 

boundaries on the Lower Roberts and Mesa terraces 

should not occur (fig. 18). More significantly, such a 

trend is contradicted by the orographic effect of 

increasing rainfall with altitude. (3) Less snow may 

accumulate on higher, more exposed terraces, leaving 

them drier. Again, the boundaries on the Lower 

Roberts and Mesa terraces should not be the same in 

this case, but such a phenomenon might account for 

the boundary shift on younger terraces.

The most common explanation for changes in 

calcic-noncalcic soil boundaries elsewhere is based on 

climatic change. Dan and Yaalon (1971) attributed to 

past climatic change the inter finger ing relationships of 

red noncalcareous paleosols and brown calcareous 

paleosols on loess. Richmond (1972) presented a plot 

similar to that in figure 18 for several areas in the 

Rocky Mountains and suggested that the higher calcicnoncalcic soil boundaries on older deposits formed 

during interglacial periods that were more arid than 

the present. If this explanation is applied to Rock 

Creek, it indicates a regular increase in aridity of 

progressively older interglacials during the past 

600,000 years (fig. 18). Two lines of circumstantial 

evidence suggest weaknesses in this hypothesis. First, 

pedogenic clay in mountain-front soils and the extent 

of till deposits suggests that the most recent 

glaciation was about as wet as those in the past. The 

climatic change hypothesis would require older 

interglacials to be drier. Trends in glacial climates 

need not be linked necessarily to trends in interglacial 

climates, however. Second, the pedogenic CaCO3 in 

older soils near the mountain front is powdery and is 

probably easily dissolved. Because moisture from this

The calcic-noncalcic soil boundary is defined as 

the geographic position where pedogenic CaCO3 first 

appears going downstream on each terrace.

D24 Soil Chronosequences in the Western United States
or previous glaciations was capable of moving clay to 

the same depth in all mountain-front soils, why would 

not soluble CaCO3 occur at similar depths and 

distances from the mountain front in all ages of 

transition soils?

A last hypothesis for the shifting calcicnoncalcic soil boundary is based on the morphology of 

CaCO3 in soils near the boundary. Isolated patches of 

CaCOg occur in these soils that in general are free of 

pedogenic CaCOo. CaCOo that accumulates close to 

the boundary during a dry interglacial episode may not 

be entirely dissolved in the following glaciation, being 

preserved in favorable spots where the soil 

microenvironment is relatively dry. These remnants 

can then act as nuclei in the next dry period and 

permit CaCOg to build up more rapidly closer to the 

mountain front than in the previous interglacial. 

Alternatively, the calcic^oncalcic soil boundary may 

be related to age-dependent textural fining: CaCOg 

precipitated at a given wetting depth may be 

protected from subsequent leaching by accumulation 

of near-surface fines that increase the soil AWC 

(available water-holding capacity). With time and 

multiple climatic changes, the boundary is pushed 

closer to the mountain front without requiring an 

overall change in the average climate. More work is 

needed to verify which of these two hypotheses 

progressively drier interglacials in the past or agerelated boundary shift is correct.

The relation of modern water movement on 

terraces at Roberts to wetting depths of CaCOg and 

pedogenic clay provides insight into past climatic 

changes (fig. 19). Depth to the shallowest occurrence 

of CaCOg and to continuous horizons of CaCOg shows

5600

- 1200 -

0 5 10 15 20 

DISTANCE OF BOUNDARY FROM MOUNTAIN FRONT. IN MILES

Figure 18. Terrace age (solid line) and altitude (dashed 

line) of calcic-noncalcic soil boundary plotted against 

distance of boundary from mountain front. Horizontal 

bars give range of position of boundary. Vertical bars 

on age line are estimated age ranges of terraces; 

vertical bars on elevation line are altitude ranges of 

boundary. P, Pinedale; BL, Bull Lake; B, Boyd; LR, 

Lower Roberts; M, Mesa.

no trends with soil age. This is not surprising, given 

the changing position of the calcic-noncalcic soil 

boundary and the varying sampling distances from the 

mountain front. The shallowest depth of pedogenic 

clay occurs in Holocene and post-Pinedale soils, 

reflecting development under a dry interglacial 

climate; the greater depth of clay movement in older 

soils reflects development under more moist glacial 

climates. Clay depths for soils older than postPinedale may be influenced by nonclimatic processes 

such as increased AWC with age or surface erosion of 

fines. As in mountain-front soils, the similarity of the 

depths of pedogenic clay in older soils implies that 

pre-Pinedale glaciations were no more moist than the

WATER FLUX, IN CENTIMETERS PER YEAR 

5 10 15

 Depth to shallowest CaCOs

Figure 19. Water movement and pedogenic features of 

transition soils. Average yearly water movement 

(curved line) for 26-year rainfall record at Roberts 

using Arkley's (1963) method. Evapotranspiration 

estimated from temperatures at Red Lodge and 

Joliet. Limits of clay and CaCO3 calculated by 

estimating available water-holding capacity for each 

horizon from textural data (Salter and Williams, 1967) 

and expressed in centimeters of wetting depth of 

yearly precipitation. Pedogenic clay depth defined as 

base of B horizon. Terraces are H, Holocene; P, 

Pinedale; BL, Bull Lake; B, Boyd; LR, Lower Roberts; 

M, Mesa.

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D25
Pinedale glaciation. Clays in the transition soils older 

than post-Pinedale have been formed at or 

translocated to somewhat shallower depths than clays 

in mountain-front soils of the same age (compare figs. 

16 and 19). Transition soils have similar or greater 

amounts of textural fining when compared to 

mountain-front soils of the same age (figs. 10 and 

14). Thus, it appears that shallower depths of clays in 

transition soils reflects the drier climate of this zone, 

rather than lesser soil development.

Basin Soils

Basin soils display field morphology that suggests 

continuous accumulation of CaCOg. The tops of 

CaCOg horizons are smooth and do not vary greatly 

across extensive exposures. CaCOg is accumulating in 

clay-rich B2t and B3t horizons of soils (supplementary 

tables 1 and 3). This coexistence of CaCOo and clay 

has been interpreted to represent either (1) a change 

to more arid climate that permits CaCOg precipitation 

in horizons where clay was being formed or translocated (for example Gile and others, 1966), or (2) 

accumulation of CaCOg in clay-rich horizons after 

lower horizons have been plugged by CaCOg 

cementation so that soil water can no longer freely 

percolate. The oldest basin soils on Rock Creek are 

not plugged, but they may have accumulated enough 

clay and CaCOg to change the infiltration rate of 

water. However, the young post-Pinedale soils also 

possess calcareous argillic horizons. At least for these 

young soils, the B2tca and B3tca horizons probably 

reflect changes to an interglacial climate.

Basin soils preserve the most complete record of 

climatic change along Rock Creek. The climate in the 

basin area fluctuated enough to cause minor changes, 

but not enough to destroy traces of former changes. I 

infer that changes in moisture occurred from 

micromorphological relationships of CaCOg and clay 

revealed in petrographic thin sections of soil peds. 

Thin sections sections of peds from the calcareous B 

horizons show secondary CaCOg as masses within the 

soil matrix or as coatings on sand grains (fig. 20). 

Secondary CaCOg locally displays variation in texture 

and color in roughly concentric rings or sometimes in 

crosscutting relationships (fig. 20B and C). The areas 

characterized by particular textures or colors are

Figure 20. Photomicrographs (crossed nicols) of 

argillans and pedogenic CaCOg in basin soils. A, Two 

sand grains are separated by a wedge of CaCOg (c). 

Grain argillans (a) are visible along edges of both 

grains (best seen on lower side of upper left grain). B, 

Mass (c) of pedogenic CaCOg engulfs sand and silt 

grains; its rim has a different visual texture than the 

main mass. A thin white line (a) interpreted as an 

argillan separates the two textures of CaCOg. Jagged 

appearance of the contact between textures may 

reflect dissolution of part of the main mass of CaCOg 

prior to accretion of a clay band and more CaCOg. C, 

Another CaCOg mass contains two or three light 

streaks (arrows) representing argillans engulfed by 

CaCOo.

commonly outlined by very thin yellow bands (fig. 20B 

and C) that go extinct upon rotation of the microscope 

stage; these bands resemble oriented clay argillans in 

noncalcareous soils. Similar features in calcareous 

soils have been reported by Morozova (1964), Alien and 

Goss (1974), Mermut and Jongerius (1980), and 

Dalsgaard and others (1981). That clay can be 

translocated through calcareous materials has been 

documented by Goss and others (1973) in experiments 

on calcareous playa sediments.

D26 Soil Chronosequences in the Western United States
The maximum number of alternating argillans 

and CaCOg layers forming a mass of secondary CaCOg 

increases with age of the soil; that relationship may 

reflect alternations of glacial and interglacial 

climates. I believe that CaCOg precipitates in the B 

horizons of basin soils during dry interglacials. 

Moister glacial climates partly dissolve accumulations 

of CaCOg, or coat the CaCOg masses with 

translocated clay particles, forming argillans. The 

argillans are surrounded by CaCOg precipitation in the 

next interglacial period.

The depth to maximum accumulations of CaCOg 

and pedogenic clay is related to the depth of water 

penetration (fig. 21) (Jenny and Leonard, 1939; Arkley, 

1963). The upper limits of CaCOg are not shown 

because in most soils CaCOg is very close to the 

surface.

The depth to maximum CaCOg accumulation (K 

horizons in pre-Bull Lake soils) increases with age of 

the soil, suggesting that older interglacials were

WATER FLUX, IN CENTIMETERS PER YEAR 

5 10 15

Depth to maximum CaCOs

 BL

 P

Maximum depth of pedogenic clay 

 H,P,BL,B

LR,M

Figure 21. Water movement and pedogenic features of 

basin soils. Average yearly water movement (curved 

line) calculated for a 24-year record at Joliet and a 

25-year record at Laurel (soil sites lie halfway 

between these two towns) using ArkleyTs (1963) 

method. Limits of clay and CaCOg calculated by 

estimating available water-holding capacity for each 

horizon from textural data (Salter and Williams, 1967) 

and expressed in centimeters of wetting depth of 

yearly precipitation. Pedogenic clay depth defined as 

base of B horizon. Terraces are H, Holocene; P, 

Pinedale; BL, Bull Lake; B, Boyd; LR, Lower Roberts; 

UR, Upper Roberts; M, Mesa.

progressively wetter. If successively older 

interglacials were wetter, then the thickness of 

maximum CaCOg horizons should increase as CaCOg 

accumulates at progressively shallower depths. 

However, the thickness of maximum CaCOg horizons 

is random with respect to age. Alternatively, the 

trend of increasing depth to maximum CaCOg may be 

age related rather than climate related, and may be 

caused by increasing AWC by accumulation of fines.

The depth of pedogenic clay increases with the 

age of basin soils, perhaps because AWC increases with 

age. In general, pedogenic clays have moved about as 

deep in older basin soils as clays in transition soils of 

corresponding age. Because the rates of textural 

fining are similar (figs. 12 and 14), climates in the two 

areas may have been similar through time. Despite 

textural fining with age in post-Boyd to post-Pinedale 

soils, the soils have similar depths of pedogenic clay. 

As with the mountain-front and transition soils, these 

relations imply that pre-Pinedale glaciations were no 

more moist than the Pinedale glaciation.

The micro morphological evidence and the plots 

of color paling and color lightening and pedogenic 

CaCOg with time (figs. 12 and 13) indicate that while 

some dissolution and leaching of CaCOg has occurred 

in basin soils, these soils have been dominated by 

accumulation of CaCOg. This permits evaluation of 

the viability of the glacial climatic model proposed for 

basin soils (fig. 5). In the proposed model, 

precipitation is held constant, but mean annual 

temperature is decreased by 10 °C. The reconstructed 

glacial surplus of water available for leaching at 

Laurel and Joliet is 12-14 cm/yr, similar to the modern 

water surplus at Red Lodge, where no soils are 

calcareous. If the reconstruction is correct, such 

moisture conditions should have caused substantial 

dissolution of CaCOg in basin soils. In order to 

prevent removal of much CaCOg, the net yearly 

amount of moisture available to wet the soil should 

roughly equal the soil AWC. Most soils on Rock Creek 

terraces have in excess of 10 cm AWC. If the glacial 

water surplus was zero, with just enough moisture 

available to wet the soil, but not leach it of soluble 

material, actual precipitation would have had to 

decrease by about 50 to 60 percent. Gates (1976) 

modeled a 35 percent decrease of precipitable 

moisture in the northern hemisphere at 18 ka.

Summary of Climatic Inferences

The transition and basin soils show evidence of 

periodic dissolution of CaCOg that is consistent with 

periodically greater effective glacial soil moisture 

reconstructed by assuming a 10 ^C decrease in mean 

annual temperature. This model must be modified by a 

decrease in mean annual precipitation on the order of 

50 to 60 percent in order to preserve most of the 

CaCOg in the basin soils. The decrease in 

precipitation may have been regional in extent, but no 

reinforcing evidence can be derived from mountain or 

transition soils.

The depths of pedogenic clay indicate that 

glacial climate in all three chronosequences during the 

Pinedale glaciation was about as wet as previous 

glaciations. The decreasing depth of clays in a

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D27
downstream direction for soils on any given terrace 

suggest that climate has been consistently drier away 

from the mountain front.

The climate of interglacials is inferred from 

positions of pedogenic CaCO3 in basin soils, and from 

the changing position of the calcic-none ale ic soil 

boundary. Data from the calcareous horizons of basin 

soils are ambiguous. The increasing depth to maximum 

pedogenic CaCOg may indicate that older interglacials 

were more moist. But thicknesses of the maximum 

CaCOg horizons do not increase with soil age, and this 

argues against such a trend in interglacial climates. If 

Richmond's (1972) model is correct, the calcicnoncalcic soil boundaries suggest that interglacials 

have become progressively wetter since 600,000 years 

ago. However, the approach of the boundary to the 

mountain front with time could reflect normal soil 

processes rather than changes in interglacial climate.

Glacial-interglacial climatic changes are 

represented in outcrop by wavy, irregular upper 

boundaries of calcareous horizons in transition soils (an 

interglacial to glacial change), and by precipitation of 

CaCOo in the B horizons of basin soils (a glacial to 

interglacial change). Micromorphological relationships 

between pedogenic CaCOg and oriented clay bands in 

basin soils appear to preserve evidence of multiple 

climatic oscillations.

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FIELD METHODS AND CALCULATIONS

Sampling and Description

Soils studied along Rock Creek were sampled in 

hand-dug holes or backhoe pits at sites that had 

minimal amounts of postdepositional erosion or 

burial. These sites were supplemented by exposures in 

gravel pits, irrigation ditches, and readouts

(supplementary table 1, part 1, and fig. 2). Replicate 

soils on terraces in a given climatic zone were sampled 

locally in order to assess soil variability.

Sites were selected to minimize differences in 

present relief. Initial depositional relief probably 

influenced soil development, but it is impossible to 

assess this effect without extensive replicate 

sampling. All sites are located on the best preserved 

north- or east-sloping terrace surfaces available. The 

soils sampled in commercial gravel pits have relatively 

thin A and B horizons because the pits are usually 

located on the edges rather than in the centers of 

terraces (fig. 2). The Upper Roberts terrace remnants 

are not well preserved, and near-surface calcic 

horizons may reflect soil erosion from these 

remnants. This is especially noticeable in the basin 

chronosequence, where post-Upper Roberts soils RC44 and RC-25 are calcareous at the surface. The Mesa 

terrace has been exposed to weathering for 2 million 

years, so it is not surprising that some soils on this 

surface (RC-28, RC-8, and RC-26B) show signs of 

erosion (such as thin or abnormally clay-poor horizons).

Horizon nomenclature and soil property 

descriptions (supplementary table 1, part 2) foEow Soil 

Survey Staff (1975) usage, with the following three 

exceptions. (1) Texture modifiers were added to 

describe gravel content. (2) The letter "K" designates 

a horizon dominated by pedogenic CaCOg (Gile and 

others, 1965). CaCO3 stages follow those proposed by 

Bach man and Machette (1977). (3) Field textural 

descriptions for Rock Creek soils were corrected using 

laboratory-determined carbonate-free particle-size 

data. Moist and dry colors were obtained with a 

Munsell soil color chart. pH was determined in the 

laboratory with a pH meter.

Index of Soil Development

Soil field data, which is measured mainly on 

ordinal scales, were converted to ratio data using 

Harden's (1982a) index of soil development, in which a 

point system is used to quantify various field 

properties of soils. Points for each horizon are then 

normalized to give all properties equal scales and 

multiplied by the horizon thickness; the products are 

summed for each soil. Thus, individual properties can 

be examined with depth in one soil or compared 

between soils, or several properties can be combined 

to obtain a profile-development index value for each 

soil.

Two modifications were made to Harden's 

index. (1) Color paling and color lightening in the 

index are two separate color properties that assess the 

increase of CaCOg in a soil (Harden and Taylor, 

1983). Because the two properties reflect the same 

phenomenon, they were combined in the present study 

into one property. (2) The change of pH in the index is 

assessed in terms of pH lowering, and this works well 

in relatively moist environments, such as the 

mountain-front climate at Red Lodge. In the 

transition and basin chronosequences, however, pH can 

either decrease or increase (supplementary table 1, 

part 2) depending upon depth in the soil profile. Values 

of pH in the latter chronosequences generally decrease 

from the parent material state in A and B horizons,

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D31
but increase in the calcareous K and C horizons. 

Change in pH for the transition and basin 

chronosequences was therefore quantified as the 

increase of pH from the parent material state. Parent 

material pH was determined from modern river 

deposits and relatively unaltered Holocene-aged C 

horizons, and increases along the transect from 6.8 at 

the mountain front, to 7.4 in the transition zone, to 8.0 

in the basin. 1.5 was used as the normalization value 

for pH increase, because that was the maximum value 

of pH change observed in these soils; 3.5 was used to 

normalize pH decrease (calculation method in Harden, 

1982a).

Dust Traps

A dust trap was set out near Joliet (fig. 2) to 

assess aerosolic additions to the soils. A plastic-lined 

aluminum tray, 29.5 x 29.5 x 6.5 cm in size, was filled 

with marbles and mounted on a pole about 2 m above 

the ground (Gile and Grossman, 1979). After one year 

the trap was removed and the dust collected by 

washing the trap and marbles with distilled water. 

Upon collection it was learned that the trap on Rock 

Creek may have received greater than normal 

atmospheric fallout because a nearby field had been 

plowed. This problem exemplifies the more general 

problem of increased regional dust fallout due to 

human activities. Nevertheless, dust trap data seems 

better than no data at all, and may at least suggest 

trends in eolian influence on soil development over 

long time periods.

Micromorphology

Oriented soil peds were collected from horizons 

of many soils. These were later impregnated with blue 

epoxy and thin-sectioned in order to investigate the 

micromorphological relationships of various soil 

components. Of special interest in Rock Creek soils 

was the relation of pedogenic CaCO3 and translocated 

clay particles.

Water Movement

Arkley's (1963) method of calculating water 

movement in soils is used to examine the relationship 

between local climate and the depth of clay or CaCOg 

accumulation. Month-by-month precipitation data for 

the climate records at several towns, and average 

monthly potential evapotranspiration (using van 

Hylckama's method, 1959), are used to calculate 

monthly excesses of precipitation over evaporation 

that is, the depth of water available to wet the soil in 

a given month. The average amount of water per year 

that passes any given depth in a soil can then be 

calculated. If the available water-holding capacity 

(AWC) of the various horizons is known or can be 

estimated, the amount of water can be plotted against 

actual soil depth. AWC is usually measured in the 

laboratory, but for this study it was estimated from 

field textural data using Salter and Williams's (1967) 

method. They state that their method has a mean 

error for estimated vs. measured AWC values of ±10 

percent using a 10 textural-class (laboratory) system.

D32 Soil Chronosequences in the Western United States
SUPPLEMENTARY TABLES
Supplementary table 1, part 1. Sample locations and site conditions

[Percentage of bare ground (in parentheses) is strongly influenced by cultivation and grazing 

practices. Parent material textures: gr/S = gravel and sand, SL = sandy loam, L = loam]

Site

Named 

terrace Elevation Modern 

deposit (ft) vegetation

Modern 

land 

use

Type of 

excavation

Parent 

material 

texture

Location 

(Montana Base 

Meridian)

Mountain-front chronosequence

RC-38

RC-21

RC-15

RC-31

RC-17

RC-30

RC-29

RC-16

RC-28

RC-14

Holocene

Pinedale

Pinedale

Bull Lake

Bull Lake

Boyd (?)

Lower(?)

Roberts

Lower(?)

Roberts

Mesa

Mesa

5,700

5,780

5,625

6,010

5,670

6,010

6,060

5,510

6,050

5,865

mixed aspen

and meadow (0)

meadow, nearby

forest (0)

mixed conifer/

aspen, mead ow(0)

meadow,

sagebrush (5)

meadow, alder

(5)

meadow,

sagebrush (5)

meadow,

sagebrush (5)

meadow,

sagebrush, (5)

meadow,

sagebrush (5)

meadow, alder,

sagebrush (5)

grazing

residential

residential

grazing

grazing

grazing

grazing

cultivation

grazing

grazing,

hay

back hoe

back hoe

roadcut

back hoe

irrigation

ditch

backhoe

gravel pit

gravel pit

backhoe

Irrigation

ditch

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

SW/4

T.

NE/4

T.

SW4/

T.

, NW/4, NW/4

8 S., R.

, SW/4, NE/4

8 S. , R.

, SW/4, NE/4

7 S., R.

SW/4, NW/4, NE/4

T.

SW/4

T.

NW/4

T.

SE/4

T.

SE/4

14

NW/4

T.

SW/4

T.

8 S. , R.

, NW/4, NW/4

7 S., R.

, NE/4, NE/4

8 S., R.

, SE/4, NE/4

8 S. , R.

, NE/4, SW/4

, T. 7 S. ,

, NW/4, SE/4

8 S., R.

, SE/4, SW/4

7 S. , R.

, Sec.

20 E.

, Sec.

20 E.

, Sec.

20 E.

, Sec.

20 E.

, Sec.

20 E

, Sec.

20 E.

, Sec.

20 E.

, Sec.

R. 20

, Sec.

20 E.

, Sec.

20 E.

3,

4,

34,

9,

27,

9,

9,

14,

E.

3,

26,

Transition chronosequence

RC-40

RC-42

RC-22

RC-12

RC-32

RC-41

RC-11

RC-37

RC-34

RC-35

RC-6

RC-36

RC-33

RC-8

Holocene

Holocene

Pinedale

Bull Lake

Bull Lake

Bull Lake

Boyd

Boyd

Lower

Roberts

Lower

Roberts

Upper(?)

Roberts

Upper

Roberts

Mesa

Mesa

4,520

4,305

4,465

4,820

4,525

4,420

4,525

4,425

5,115

4,265

4,480

4,320

5,245

5,145

meadow, riparian

vegetation (0)

grasses (0)

grasses,

thistles (5)

grasses, alder,

sagebrush (5)

grasses (0)

grasses (5)

grasses,

sagebrush (10)

grasses ,

sagebrush (10)

grasses,

sagebrush (10)

grasses, cactus,

sagebrush (20)

grasses,

sagebrush (10)

grasses, cactus,

sagebrush (20)

grasses,

sagebrush (10)

grasses,

sagebrush (10)

grazing

grazing,

hay

grazing

grazing,

hay

grazing,

hay

grazing,

hay

grazing,

hay

grazing,

hay

grazing,

hay

grazing

cultivation

grazing

grazing

grazing

stream cut

backhoe

strearacut

gravel pit

roadcut

hand-dug

hole

gravel pit

gravel pit

backhoe

backhoe

gravel pit

backhoe

backhoe

gravel pit

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

SL,

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

gr/S

NW/4

T.

NW4/

T.

NW4/

T.

SW/4

T.

NE/4

T.

SE/4

T.

NE/4

T.

SE/4

T.

SE/4

T.

NW/4

T.

SW/4

T.

NE/4

T.

NW/4

T.

SW/4

T.

, NW/4, NE/4

5 S., R.

, NE/4, NE/4

5 S., R.

, SW/4, NW/4

5 S., R.

, NE/4, NE/4

6 S., R.

, NE/4, NE/4

5 S., R.

, SW/4, SE/4

5 S., R.

, SW/4, NW/4

5 S., R.

, SE/4, SE/4

5 S., R.

, NW/4, SW/4

6 S., R.

, SE/4, NE/4

4 S., R.

, SW/4, NE/4

5 S., R.

,SE/4,SW/4

4 S., R.

, SE/4, NW/4

6 S., R.

, NW/4, SW/4

6 S., R.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

20 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

, Sec.

21 E.

32,

16,

28,

12,

30,

17,

28,

16,

30,

36,

15,

36,

33,

27,

D34 Soil Chronosequences in the Western United States
Supplementary table 1, part 1. Sample locations and site conditions Continued

Site

Named 

terrace Elevation Modern 

deposit (ft) vegetation

Modern 

land 

use

Type of 

excavation

Parent 

material 

texture

Location 

(Montana Base 

Meridian)

Basin chronosequence

RC-46A

RC-46B

RC-20

RC-43

RC-27

RC-23

RC-24

RC-25

RC-44

RC-26A

RC-26B

Holocene

Holocene

Pinedale

Pinedale

Bull Lake

Boyd

Lower

Roberts

Upper

Roberts

Upper

Roberts

Mesa

Mesa

3

3

3

3

3

3

3

3

3

4

4

,387

,387

,480

,430

,465

,620

,700

,810

,850

,495

,490

grasses (5)

grasses (5)

grasses, edge of

cornfield (5)

grasses, edge of

wheatfield (5)

grasses,

sagebrush (5)

grasses,

sagebrush (20)

grasses,

sagebrush (20)

grasses,

sagebrush (20)

grasses,

sagebrush (20)

grasses, sagebrush, pines(lO)

grasses, sagebrush, pines(lO)

grazing,

residential

grazing,

residential

cultivation

cultivation

cultivation

grazing

grazing

grazing

grazing

grazing

grazing

backhoe

backhoe

gravel pit

gravel pit

backhoe

backhoe

backhoe

hand-dug

hole

hand-dug

hole

backhoe

backhoe

L,gr/S

L,gr/S

SL,gr/S

L,gr/S

SL,gr/S

SL,gr/S

SL,gr/S

SL,gr/S

SL,gr/S

SL,gr/S

SL,gr/S

SE/4

T.

SE/4

T.

SE/4

T.

SW/4

T.

SE/4

T.

SE/4

T.

NE/4

T.

SW/4

T.

SE/4

T.

SW/4

T.

NE/4

T.

,NE/4

3 S.

,NE/4

3 S.

,SE/4

4 S.

,NE/4

3 S.

,SW/4

3 S.

,NE/4

3 S.

,SW/4

3 S.

,SW/4

3 S.

,SW/4

3 S.

,SW/4

5 S.

,SW/4

5 S.

,SW/4, Sec.

, R. 23 E.

,SW/4, Sec.

, R. 23 E.

,SW/4, Sec.

, R. 23 E.

,SW/4, Sec.

, R. 23 E.

,NE/4, Sec.

, R. 23 E.

,SE/4, Sec.

, R. 23 E.

,NE/4, Sec.

, R. 23 E.

,SW/4, Sec.

, R. 23 E.

,SE/4, Sec.

, R. 23 E.

,SE/4, Sec.

, R. 22 E.

,SE/4, Sec.

, R. 22 E.

25,

25,

11,

36,

23,

34,

34,

27,

28,

12,

12,

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D35
Supplementary table 1, part 2. Field descriptions

[Analyst: M. C. Rebels, U.S. Geological Survey. , not measured]

Surface 

and

age,

ka Sample Horizon

Depth Lower

(cm) boundary

Moist

color

Dry

color

Wet

Assumed parent 

material (<2 mm)

consis- Clay

Texture Structure tence films pH Texture

Wet consistenceStage

CaCO,

Mountain-front chronosequence

Holocene

7

Pinedale

20

Bull Lake

120

Boyd

415

Lower (?)

Roberts

600

Mesa

2,000

RC-38

RC-21

RC-15

RC-31

RC-17

RC-30

RC-29

RC-16

RC-28

RC-14

Al

2A31

2A32

2AC

3CjOX

3C2 ox

A

Bit

B2t

2B3t

3CjOx

3C2 ° X

A

2B2t

2B3

2Cox

Al

A3

Bit

B21t

B22t

2B31t

2B32t

2Cox

A

Bit

B2t

B31t

2B32t

2Cox

Al

A3

Bit

B2t

2B31t

2B32t

2Cox

Al

A3

Bit

B2t

2B31t

3B32t

3Cox

A

Bit

2B2t

2B3t

2Cox

A

Bit

B2t

2B31t

2B32t

2Cox

A

Bit

B2t

2B31t

3B32t

3Cox

0-9 c,s

9-22 g,s

22-33 g.w

33-46 g,w

46-85 g,w

85-120+ 

0-5 g,s

5-12 g,s

12-25 g,s

25-38 g,w

38-73 g,s

73-110+ 

0-8 g,s

8-23 g,s

23-43 d

43-68+

0-8 c,s

8-19 g,s

19-32 d

32-54 c,s

54-81 c,s

81-123 d

123-145 d

145-200+ 

0-9 g,s

9-20 g,s

20-31 g,s

31-50 g,s

50-122 d

122-136+ 

0-9 g,s

9-17 c,s

17-29 g,s

29-53 g,s

53-81 d

81-170 d

170-250+ 

0-9 c,s

9-18 g,s

18-30 g,s

30-50 g,s

50-79 g,s

79-167 d

167-260+ 

0-27 g,s

27-47 g,s

47-72 g,s

72-127 g,s

127-197+ 

0-7 c,s

7-11 c,s

11-17 c,s

17-47 g,s

47-141 d

141-270+ 

0-17 g,s

17-32 g,s

32-44 g,s

44-84 g,s

34-144 d

144-164+ 

10YR2/1

10YR2/2

10YR2/2.5

10YR3/3

10YR5/4

10YR5/3

7.5YR2/2

7.5YR3/3

7.5YR3/4

7.5YR4/6

10YR4/4

10YR5/4

7.5YR2/2

7.5YR2/3

7.5YR3/5

7.5YR4/4

7.5YR2/1

7.5YR2/1.5

7.5YR4/4

7.5YR4.5/6

5YR4/8

10YR5/6

10YR4/6

10YR5/5

7.5YR2/2

7.5YR2/4

7.5YR4/4

7.5YR4/5

7.5YR4/8

10YR4/5

10YR2/2

10YR2/1

7.5YR3.5/4

7.5YR4/6

7.5YR4.5/6

8.75YR5/5

10YR5/5

7.5YR2/1.5

7.5YR2/2

7.5YR3/3

7.5YR4/4

7.5YR3/3

10YR4/4

10YR5/4

10YR2/3

7.5YR3/4

7.5YR4/8

7.5YR4/6

10YR5/5

7.5YR2/2

8.75YR2/2

7.5YR3/4

7.5YR4/4

7.5YR4.5/5

10YR5/5

7.5YR2/2

7.5YR3/4

5YR4/5

7.5YR4.5/6

7.5YR4.5/6

10YR4/6

2.5Y4/2

10YR4/2

10YR4.5/2.5

10YR5/3

2.5Y6/2.5

10YR6.5/3

7.5YR4/3

7.5YR4.5/4

7.5YR4.5/4

7.5YR5/5

10YR6/5

10YR7/4

10YR2/3

7.5YR4/3

7.5YR4/4

7.5YR5/5

7. SYR

3.5/2.5

7. SYR

3.5/2.5

8.75YR5/4

8.75YR6/5

5YR5/7

10YR6/5

10YR5.5/6

10YR6/5

7.5YR4/3

7.5YR4.5/4

7.5YR5/5

7.5YR5/6

7.5YR5.5/8

10YR6/4

10YR3/2

10YR3/2

8.75YR4/5

7.5YR4.5/6

7.5YR5/5

8.75YR6/7

10YR6/6

7.5YR4/3

7.5YR4/2.5

8.75YR4/3

8.75YR5/5

8.75YR4/3

10YR6/5

10YR6/5

10YR3/3

7.5YR4/4

7.5YR4/8

7.5YR4/7

10YR5/6

7.5YR4/2.5

8.75YR4/3

8.75YR4/4

7.5YR4.5/5

7.5YR5.5/6

10YR5.5/6

7.5YR3/3

7.5YR4.5/4

7.5YR5/5

7.5YR5/6

7.5YR5/6

10YR5.5/6

sgLS

sgLS

gLSgs

vgLSvgLSsgSL

gSL+

gL

vgSL

vgS

vgS

sgSL

vgSLvgLSvgS

sgSL

sgSL

gSL+

gSL

gSCL+

vgLS

vgLS

vgS

sgL

sgSCLgSCLgSL+

vgLS

vgS

sgSL

sgSL

gSL

gSL

vgSL

vgLS+

vgS

sgSL

gSL

gSL

gSL

vgSL

vgLS

vgLS

sgSL

gSL

vgSL+

vgSL+

vgLS

sgSL

gSLgSL

vgSLvgLS

vgS

sgSL+

sgSCLsgSCLgSL

vgLS+

vgS

Igr

2gr,lfsbk

2gr,lfsbk

sg, Ifsbk

m

m

Igr

Ifsbk

1ms bk

1ms bk

m

m

Igr

Ifsbk

sg,m

m

2gr

2gr,

2fsbk

2m-csbk

2m-csbk

3csbk

2f-msbk

sg,m

m

2fsbk

Ifsbk,

Igr

2ms bk

2csbk

2csbk,sg

m

2gr

2gr,2fsbk

If-rasbk

3csbk

3ms bk

sg,m

m

2gr

2gr, 1ms bk

2ms bk

2m-csbk

2ms bk

sg,m

m

2gr

3fsbk

3ms bk

sg,m

m

Igr

2ms bk

2msbk

Ifsbk

sg,m

m

2gr

2ms bk

3ms bk

Ifsbk

sg,m

m

so,po

so,po

so,po

so, po

so,po

so.po

so,po

ss,ps

ss,ps

ss, po

so,po

so, po

so,po

so,po

so,po

so, po

so,po

ss,ps

s,p

s,p

S,p

ss,po

so,po

so,po

so, ps

so,ps

s,p

s,p

so,po

so,po

so,po

so, po

s,ps

s,p

ss,ps

so,po

so.po

so,po

so,po

so,po

s,ps

s,ps

so,po

so, po

ss,po

s,ps

s,ps

ss.po

so,po

so, po

so,po

so,ps

so,po

so, po

so,po

ss.ps

s,p

vs, vp

ss,ps

so.po

so,po

0 6.3

0 6.1

0 6.0

0 6.0

0 6.3

0 5.9

0 6.1

Inpf 6.3

Inpf 6.3

0 6.4

0 6.6

0 6.8

0 6.0

Inco 5.9

0 5.8

0 6.0

0 6.5

0 6.0

2npf 6.1

2npf 6.2

2npf 6.3

2nco 6.6

Inco 6.8

0 6.8

0 6.4

0 6.1

2npf 5.8

2npf 5.4

Inco 5.7

0 5.1

0 6.2

0 6.1

2npf 6.1

3npf 6.2

3nco 6.4

Inco 6.7

0 6.7

0 6.2

2npf 5.9

3npf 5.9

3npf 6.0

3npf 5.9

2nco 6.7

0 6.9

0 5.4

2npf 5.6

3mkpf 5.6

2nco 5.9

0 5.7

0 6.0

Inpf 6.0

2npf 6.0

Inpf 6.0

Inco 6.6

0 7.1

0 5.3

3mkpf 5.6

3tnkpf 5.6

2npf 5.6

2nco 6.2

0 6.3

LS

LS

S

S

LSLSSL

SL

SL

LS

S

S

SL

S

S

S

LS

LS

LS

LS

LS

S

S

S

SL

SL

LS

LS

S

S

SL

SL

LS

LS

S

S

S

LS

LS

LS

LS

LS

S

S

SL

LS

LS

LS

LS

LS

LS

LS

S

S

S

SL

SL

SL

LS

LS

S

so,po

so,po

so,po

so,po

so.po

so,po

so.po

so, po

so,po

so, po

so,po

so.po

so,po

so.po

so,po

so.po

so,po

so,po

so,po

so,po

so, po

so,po

so,po

so,po

so.po

so.po

so.po

so,po

so,po

so, po

so.po

so, po

so.po

so,po

so,po

so.po

so,po

so.po

so,po

so,po

so,po

so,po

so,po

so.po

so,po

so, po

so.po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

so.po

so,po

so,po

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

D36 Soil Chronosequences in the Western United States
Supplementary table 1, part 2. Field descriptions Continued

Surface 

and 

age, 

ka

Holocene

7

Pinedale

20

Bull Lake

120

Boyd

415

Lower

Roberts

600

Depth Lower Moist 

Sample Horizon (cm) boundary color

RC-40 A 0-13 c,s

3s 13-46 g,w

2C 1 ox 46-75 g

2C2 ox 75-310 va

R 310+

RC-42 Al 0-6 g

A3 6-37 g

2Bs 37-55 a,w

3Bb 55-73 c,s

3Coxb 73-200"*" ~

RC-22 A 0-5 g,s

Bit 5-25 g,s

B2t 25-43 g,s

2B3t 43-57 g,s

2C,ox 57-78 g,s

2C2 ox 78-175 a,s

3Cca 175-197 c,s

3Cn 197-240"1" 

RC-12 A 0-9 g,s

Bit 9-17 g,s

B2t 17-39 g,s

2B3t 39-62 d

2Cox 62-122 

RC-32 Ap 0-21 a,s

2B2tca 21-37 g,s

2B3tca 37-70 g,s

3Cca 70

RC-41 A 0-8 g,s

Bit 3-17 c,s

B2t 17-28 g,w

2B31t 28-51 d

2B32t 51-65 d

2Cox 65-100+ 

RC-11 A 0-9 g,s

B2t 9-20 g,s

B3t 20-50 a,i

2C,ca 50-100 d

2C2 ca 100-180+ 

RC-37 A 0-6 c,s

Bit 6-18 g,s

B2tca 18-45 a,i

B3tca/K 45-63 g,s

2C,ca 63-109 d

3C 2 ca 109-230 d

3C 3 ca 230^

RC-34 Al 0-8 g,s

A3 8-14 g,s

Bit 14-22 c,s

B2t 22-37 g,i

2B3t/ca 37-54 g,i

3Cox/ca 54-89 g,s

3C t ca 89-160 d

3C 2 ca 160-210+ 

RC-35 A 0-5 c,s

Bit 5-10 c,s

B2tca 10-18 c,s

B3tca 18-32 g,s

2C.ca 32-54 g,s

2C 2 ca 54-135 d

2C 3 ca 135-225 d

2C4 ca 225+

10YR2/2

10YR2/2.5

10YR4/4

10YR5/3

10YR2.5/2

10YR2/2

10YR3/3

10YR2/3

10YR4/4

10YR3/2

10YR2/3

7.5YR3/2

10YR3/2

10YR3/3

10YR5/4

2.5Y5/3

2.5Y5/3

10YR2/3

7.5YR4/4

7.5YR4/7

7.5YR4/6

7.5YR5/6

10YR5/3

10YR3/2.5

10YR4/4

10YR5/4

10YR3/2

10YR3/2

8.5YR4/6

10YR3.5/4

10YR4/4

10YR5/4

7.5YR3/3

7.5YR3/6

7.5YR4/4

10YR7/3

10YR6/3

10YR2.5/2

10YR3/2.5

10YR3.5/3

10YR7/3

10YR5.5/3

2.5Y6/2

--

10YR3/2

10YR

2.5/1.5

10YR2/2

7.5YR4/3

10YR3/3.5

10YR4/3/

10YR6/2.5

2.5Y5/2.5

2.5Y5/2.5

10YR3/2

10YR3/2

10YR3/3

10YR5/4

10YR6/3

10YR6/3.5

10YR5.5/4

10YR5/5

Dry 

color

Transition

2.5Y4/2

10YR4/3

10YR5/4

10YR6/3

10YR4/3

10YR4/2

10YR4.5/3

10YR4/3

10YR5/4

10YR5/3

10YR4/2.5

7.5YR4/3

10YR4/2.5

10YR5/3

10YR6/4

2.5Y6/3

2.5Y7/3

10YR4/4

7.5YR5.5/5

7.5YR4/8

7.5YR4.5/6

7.5YR5/6

10YR5/3

10YR3/1.5

10YR5/4

10YR6/4

10YR5/3

10YR5.5/2.5

8.5YR4/4

10YR4/4

10YR5/4

10YR6/6

10YR3/4

7.5YR3/6

7.5YR4/5

10YR7/3

10YR6/3

10YR4/2.5

10YR4/2.5

10YR4/3

10YR8/1

10YR7/3

2.5Y7/3

10YR4/2.5

10YR4/2.5

10YR4/2.5

8.75YR5/4

10YR4/3

10YR5/3/

10YR7/2.5

2 . 5Y7 / 2 . 5

2.5Y7/2.5

10YR4/2.5

10YR4/3

10YR4/2.5

10YR6/3

10YR8/2.5

10YR7/2.5

10YR7/3.5

10YR7/3.5

Texture Structure

Wet 

consistence

Assumed parent 

material «2 mm)

Clay 

films pH Texture

Wet consistenceStage 

CaC0 3

chronosequence

gfSL

gfSL

vgS

vgS

--

gSL

vgSL

sgSL

vgSL

vgS

sgL

sgSL

gSL+

vgSLvgLS

vgLS

vgS

vgS

vsgL

sgCLgSCL

vgSL+

vgS

SgC

gSCL

gSL+

vgLSsgfSL

gL

gSCL+

vgSLvgSL

vgS

gSL

vgSCL

vgSL+

vgLS

vgS

vsgSL

sgL

sgSCLsgSCL

vgSL+

vgS

vgS

sgSL+

sgSL+

sgSL+

sgL

gSL

vgLS

vgS

vgS

sgfSL

sgSCLsgSCL

gSLvgLS

vgLS

vgS

vgS

Igr, 1ms bk

2csbk

m

m

Igr

Ifsbk

1ms bk

Ifsbk

m

2gr

Ifsbk

2ms bk

sg

m

m

m

m

2gr

2gr, Ifsbk

Ifsbk

Ifsbk

m

2fabk

1ms bk

2ms bk

m

2gr

2rasbk

2csbk

2msbk

If-msbk

m

2gr

2msbk

1ms bk

m

m

2gr

2ms bk

2m-csbk,

Impr

Ifsbk,

Impl

m

m

m

2gr,lfpl

2gr,

2msbk

2ms bk

3m-csbk

Ifsbk

m

m

m

2gr

2ms bk

2m-csbk

If-msbk

m

m

m

m

so, poso,po

so, po

so.po

--

so,po

so, po

so,po

so, po

so,po

so, po

ss,ps

s ,ps

so.po

so, po

so.po

so,po

so,po

so.po

s,p

S,p

ss,po

so,po

vs,vp

s,p

s,p

so, po

so,po

s,p

s,p

s,ps

ss,po

so, po

so.po

S,p

s,ps

so.po

so.po

so, po

s,p

S,P

ss, p

ss, ps

so, po

so.po

so, po

ss,ps

s,p

vs ,p

so,po

so.po

so,po

so.po

so,ps

ss,ps

s,P

so.ps

so, po

so,po

so, po

so.po

0

0

0

0

--

0

0

0

0

0

0

0

Inpf

0

0

0

0

0

0

Inpf

Inpf

Inco

0

0

Inpf

2np f

2nco

Inco

0

0

Inpf

2nco

0

0

0

Inpf

2npf

0

0

0

0

0

0

Inpf

2npf

0

0

0

0

0

2npf

2mkpf

Inpf

0

0

0

0

7.1

6.6

6.8

7.0

"-

7.1

6.1

6.7

6.8

7.0

6.9

6.6

6.8

6.9

7.1

6.9

7.9

7.7

6.2

6.4

6.4

6.8

7.0

7.2

7.5

8.0

8.1

6.7

6.6

6.5

6.7

7.1

7.3

5.6

5.7

6.4

7.5

7.7

7.0

7.1

7.3

7.7

7.8

8.1

5.7

5.4

5.5

5.5

6.1/7

6.7

7.9

7.8

6.9

6.5

7.0

7.5

7.6

7.9

8.0

8.0

SL

SL

S

S

_ .

SL

SL

SL

LS

S

SL

SL

LS

LS

LS

LS

S

S

SL

SL

SL

S

S

SL

LS

LS

S

SL

LS

LS

S

S

S

LS

LS

LS

S

S

SL

SL

SL

LS

LS

S

S

SL

SL

SL

SL

.6 LS

S

S

S

SL

SL

LS

LS

S

S

S

S

so, po

so,po

so, po

so.po

--

so, po

so, po

so,po

so, po

so,po

so, po

so.po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

so.po

so, po

ss,ps

so.po

so,po

so, po

so,po

so.po

so.po

so,po

so.po

so, po

so,po

so, po

so,po

so, po

so.po

so, po

so,po

so, po

so,po

so.po

so, po

so,po

so, po

so,po

so,po

so, po

so, po

so, po

so, po

so.po

so, po

so.po

so, po

so.po

so, po

SO,pD

so, po

so.po

0

0

0

0

~~

0

0

0

0

0

0

0

0

0

0

0

I

0

0

0

0

0

0

0

I

II

I

0

0

0

0

0

0

0

0

0

11+

I

0

0

I

II/ III11+ III

0

0

0

0

0/1-

O/ IHII

I

0

0

I

II

11+

11+

II

I

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D37
Supplementary table 1, part 2. Field descriptions Continued

Surface 

and

age,

ka

Upper(?)

Roberts

945

Mesa

2,000

Holocene

7

Pinedale

20

Bull Lake

120

*

Sample

number Horizon

RC-6 A

Bit

B2t

2C,ca

2C 2 ca

RC-36 A

Bit

B2tca

B3tca

K

2C,ca

3C 2 ca

3C 3 ca

3-4C4 ca

4C5 ca

4C6 ca

RC-33 Al

A3

Bit

B2t

2B3t/

ca/Kl

2K2

3C,ca

3C 2 ca

RC-8 A

B2t

2B3tca

2K

2Cca

RC-46A Ap

ACca

2Cgca

2Cox

3Cn

RC-46B Apca

2Cca

3Cn

RC-20 A

2Blt

2B2tca

2B3tca

3C.ca

3C 2 ca

RC-43 A

Bit

62 1

2B3tca

2C,ca

3C 2 ca

RC-27 A

231t

2B2t

3B3ca

3C,ca

4C 2 ca

5C 3 ca

Depth Lower Moist

(cm) boundary color

0-13 c,w

13-30 g,s

30-46 a,s

46-96 d

96-126+ 

0-7 c,s

7-16 c,s

16-25 a,s

25-35 g,s

35-53 g,s

53-80 c,s

80-103 d

103-173 g.s

173-200 g,s

200-227 d

227-255+ 

0-9 g,s

9-16 g,s

16-24 g,s

24-43 g or

a,w

43-58 g/

c,w

58-92 g,s

92-180 g,s

180-220+ 

0-8 c,s

8-22 a.w

22-72 g.s

72-112 d

112-162+ 

0-20 a,s

20-40 a,w

40-70 c,s

70-98 a,w

93-150+ 

0-28 a,s

28-60 a,w

60-150+ --

0-9 c,s

9-15 g,s

15-32 a,w

32-50 g,s

50-130 d

130-330+ 

0-18 c,s

18-33 g,s

33-44 c,s

44-65 g,s

65-98 d

98-200+ 

0-6 c,s

6-11 g,s

11-19 a,w

19-34 g,s

34-74 a,s

74-147 c,s

147-225+ 

10YR3/2

10YR3/6

10YR4/4

10YR7/3

10YR5/5

10YR3/2

7.5YR4/3

10YR4/4

10YR5/3

2.5Y7/3

2.5Y6/3.5

2.5Y6/3

2.5Y6/3

10YR5/4

10YR5/3.5

10YR5/4

10YR3/2

10YR2.5/2

10YR3/2

10YR3/3

10YR3/2

10YR6/3

10YR7/2

2.5Y5/3

10YR4/5

10YR3/3

7.5YR4/4

10YR5/4

10YR6/3

10YR5.5/3

10YR3/2.5

10YR4/2.5

2.5Y4/2

2.5Y4/4

2.5Y4/2

10YR3/2

10YR5/3

2.5Y4/2

10YR4/3

10YR3.5/4

10YR4/4

10YR5/4

10YR5/4

2.5Y5/3

10YR4/2

10YR3.5/2

10YR3.5/3

10YR4/3

10YR5/3

2.5Y5/3

10YR4/3

10YR3/2

10YR4/3

10YR5/3

2.5Y5/3

2.5Y5/2.5

10YR5/3

Dry

color

10YR3/4

10YR4/6

10YR4/5

10YR7/2

10YR6/5

10YR4/2

7.5YR4/3

10YR5/5

10YR6/3

2.5Y8/2

2.5Y7/3

2.5Y7/3

2.5Y6.5/3

10YR6/3.5

1.25Y7/4

1.25Y7/4

10YR5/2

10YR4/2

10YR4/2.5

8.75YR4/3

10YR4/2.5

10YR7/3

10YR8/1

2.5Y7/3

10YR6/5

10YR3/4

7.5YR4/3.

10YR6.5/3

10YR8/1

10YR7/2.5

Basin

2.5Y5.5/2

10YR6/2.5

2.5Y6/2

2.5Y6/3

2.5Y6/2

2.5Y5/2

1.25Y6/2

2.5Y6/2

10YR6/3

10YR5/4

10YR4/4

10YR6/4

10YR6.5/4

2.5Y7/3

10YR5/3

10YR5/2.5

10YR4/3.5

10YR5.5/3

10YR5.5/3

2.5Y6/3

10YR6/2.5

10YR5/3

10YR4/3

10YR7/2

2.5Y7/2.5

2.5Y6/2.5

10YR6/3

Wet

Assumed parent 

material (<2 mm)

consis- Clay

Texture

vsgSL+

sgSCLsgSCL

vgLS

vgS

sgL

sgSCL+

sgSCL

sgL+

gCL

gL

sgCL

sgSiCsgL

vgLS

vgLS

sgL+

sgCL

sgCL+

sgCgSCLvgSL

vgSL

vgSL

gSCL

5 gSCL+

vgSCL

vgLS

vgSLStructure

Igr

2ms bk

3ms bk,

Impr

m

m

2gr

2ms bk

3m-csbk

Ifsbk,

Ifpl

2mpl

m

m

m

m

m

m

2gr

2gr,2fsbk

2fsbk

2csbk

Imsbk/m

m

m

m

2gr

3ra-csbk

Im-csbk

m

m

tence

ss,ps

s,p

s,p

so.po

so,po

so,po

s,p

s,p

vs , vp

vs, vp

s,p

vs, p

vs,vp

ss,ps

so,po

so.po

ss, ps

s,p

vs , vp

vs, vp

S,p

s ,ps

ss, po

so, po

s,p

vs,vp

vs,p

ss,ps

ss,po

films pH

0 6.6

2npf 6.6

3tnkpf 6.8

0 7.5

0 8.0

0 7.3

Inpf 7.1

2npf 7.5

0 7.9

0 8.0

0 8.3

0 8.3

0 8.4

0 8.5

0 8.6

0 8.4

0 6.4

0 6.6

3npf 6.6

3mkpf 6.9

2npf 7.6

0 7.9

0 8.2

0 8.2

0 7.2

2mkpf 7.0

Inpf 7.5

0 7.8

0 7.8

Texture

SL

SL

SL

S

S

LS

LS

LS

LS

LS

LS

CL

Wet consistence

so.po

so,po

so.po

so,po

so, po

so,po

so, po

so,po

so, po

so,po

so, po

vs,p

SiCL- vs,vp

L

LS

LS

LS

LS

SL

SL

LS

LS

LS

LS

SL

SL

LS

LS

LS

ss,ps

so, po

so,po

so.po

so,po

so, po

so.po

so.po

III

so, po

so,po

so,po

so.po

so, po

so,po

so, po

so,po

Stage

CaCO-j

0

0

0

III II0

0

I

11+

III

II

II

I

I

1+

I0

0

0

0

O/II/

III

II

I

0

0

II/III

III

11+

chronosequence

CLSL

CLLvgLS

sgL+

gSL

vgLS

sgL

gSCL

gSCLvgLS

vgS+

vgS

sgCLsgL

gCL

vgSL

vgS

vgS

vsgL+

gL+

vgCLL+

L+

vsgL

vgLS

Ifsbk

Ifsbk

m

m

m

1ms bk

Ifsbk

m

2gr

2fsbk

2ms bk

Ifsbk

m

m

2fpl,

1ms bk

2ms bk

2ms bk

If-msbk

m

m

2mpl

2msbk

Ifsbk

2mabk

m

m

m

ss,ps

ss,ps

so,po

so.po

so,po

ss.po

ss,po

so,po

ss,ps

s,p

s,p

ss,po

so,po

so, po

ss,ps

ss,ps

s,P

ss,ps

so.po

so,po

so, ps

ss, p

s,P

s,p

s,P

so.po

so, po

0 8.0

0 8.1

0 8.1

0 7.8

0 7.8

0 7.9

0 8.0

0 7.8

0 7.0

Inpf 7.4

Inpf 7.7

0 8.3

0 8.6

0 8.9

0 7.3

0 7.7

0 7.8

0 8.1

0 8.2

0 8.4

0 7.9

Inpf 7.5

Inpf 7.5

0 7.8

0 7.8

0 8.6

0 7.9

L

SL

L

L

LS

L

SL

LS

SL

LS

LS

LS

S

S

L

L

L

LS

S

S

SL

LS

LS

L

L

L

LS

so.po

so, po

ss.ps

ss.ps

so.po

so.po

so,po

so,po

so,po

so, po

so,po

so, po

so,po

so.po

ss,ps

ss,ps

ss.ps

so,po

so, po

so,po

so, po

so,po

so.po

ss,ps

ss,ps

so.po

so, po

0

I

I

0

0

I

I

0

0

0

I

I

III

0

0

0

II

II

I

I

I0

II

1+

I

I

D38 Soil Chronosequences in the Western United States
Supplementary table 1, part 2. Field descriptions Continued

Surface 

and 

age, 

ka

Boyd

415

Lower

Roberts

600

Upper

Roberts

945

Mesa

2,000

Sample Depth Lower Moist 

number Horizon (cm) boundary color

RC-23 A

Bltca

B2tca

B3tca

2K

3CjCa

3C2 ca

4C3 ca

5C4 ca

5C 5 ca

5C6 ca

RC-24 A

Bit

B2tca

B3tca

K

2C x ca

2C,,ca

2C 3 ca

RC-25 Aca

Bltca

B2tca

B3tca

2K

2C lCa

2C7 ca

3C3 ca

RC-44 Aca

Bltca

B21tca

B22tca

2B31tca

2B32tca

2Cca

RC-26A A

Bit

B21t

B22tca

B3tca

2K

2C lCa

2C 7 ca

2C3ca

R

RC-26B A

Bit

B2tca

B31tca

B32tca

2K

2Clca

2C 2 ca

0-3

3-7

7-14

14-29

29-60

60-121

121-170

170-226

226-255

255-310

310+

0-4

4-9

9-19

19-30

30-45

45-62

62-87

87-300+

0-4

4-9

9-15

15-25

25-49

49-65

65-91

91-130+

0-6

6-13

13-19

19.-27

27-45

45-86

86-120+

0-6

6-11

11-20

20-29

29-40

40-68

68-145

145-247

247-295

295+

0-5

5-10

10-16

16-25

25-36

36-48

48-88

88-170+

c,s

g.s

g.s

a,s

c,w

g.s

c, w

g.s

c,w

g.s

c, s

c,s

g,s

c,s

g.s

g.s

g.s

g.s

g.s

g.s

a,s

g.w

g.w

a, w

g.s

g.s

c,s

g,s

c,s

c, s

c, s

g.s

g.s

c,w

c,s

c,w

c,w

d

a,w

c,s

g.s

a, s

g.w

c,w

g.s

g.s

10YR3/2

10YR3/3

10YR3/2

10YR4/3

2.5Y7/3

10YR5/4

10YR5/5

10YR5.5/4

10YR5/5

10YR6/3.5

10YR5/5

10YR3/2

10YR3/3

10YR4/3

10YR5/3

2.5Y8/3

10YR6/3

10YR5/4

10YR6/3.5

10YR3/2

10YR

3.5/2.5

10YR4/2.5

10YR4/3

10YR6/2.5

10YR6/2

10YP5/2

10YR4/3

10YR3/2

10YR3/3

10YR4/3

10YR5.5/3

10YR6/3

10YR5/3.5

10YR4/4

10YR3/2

10YR3/2

10YR

3.5/2.5

10YR4/3

10YR5/3

10YR7/3

10YR7/3

10YR6/3.5

10YR6/4

--

10YR3/2

10YR3/2

10YR4/3.5

10YR5/3

10YR6/3

10YR7/3

10YR7/3

2.5Y6/3

Dry 

color

10YR5/3

10YR4.5/3

10YR5/3

10YR5.5/3

2.5Y8/2

10YR7/4

10YR6/5

10YR7/4

10YR6/6

10YR7/4

10YR6/6

10YR5/2.5

10YR4/2.5

10YR5/3

10YR6/3

10YR8/1

10YR7/3

10YR6/3.5

10YR8/3.5

10YR4/2

10YR5/2.5

10YR5/2.5

10YR6/3

10YR8/1

10YR7/2

10YR6/2

10YR5.5/3

10YR5/2

10YR4/3

10YR6/3

10YR6.5/3

10YR8/2

10YR5/3

10YR5/3

10YR6/3

10YR4/2.5

10YR4/3

10YR5/3

10YR6/3

10YR8/1

10YR8/2.5

10YR8/3.5

10YR7/3.5

--

10YR5/3

10YR4/2.5

10YR5/4

10YR6.5/3

10YR7/2.5

10YR3/1

10YR8/2.5

2.5Y8/3

Texture

vsgSiL

vsgL

sgL+

gSL+

vgLS

vgSL

vgLS

vgSLvgS

vgLS

vgS

sgCL

sgCL

sgSiCL

sgSiL+

sgCLvgSL

vgS

vgS

sgL

sgL

sgL+

sgL

gSL

vgSL+

vgLS

gSL

sgL

gCL

gCL

gL

gL

vgSL

vgLSsgL

sgL+

sgL+

sgL+

gL+

gSL

vgLS

vgS

vgS

sgL

sgL+

sgCL

vsgSCLsgSL+

gSL

vgS

vgS

Wet

Assumed parent 

material «2 mm)

consis- Clay 

Structure tence films pH Texture

2gr

Irasbk

2msbk

If-msbk

m

m

m

m

m

m

m

2gr

3ms bk,

Ifpl

3ms bk,

2fpl

2 f-ms bk ,

Ifpl

2mpl,m

m

m

m

2gr

2fsbk

2f-msbk

Ifsbk

m

m

m

m

Igr

2 f-ms bk

2msbk

2m-csbk

2 f-ms bk

Ifsbk

m

Igr, If P l

2ms bk

3csbk,

2mpr

2ms bk,

Impr

m

m

m

m

m

--

Igr, Ifpl

2msbk

3ms bk,

Impr

2ms bk

Ifsbk

m

m

m

so, ps

ss,ps

s,p

s,p

s, ps

so,po

so, po

so,po

so, po

so.po

so.po

s,p

vs ,p

vs ,vp

vs , vp

s,p

ss , po

so,po

so, po

so.ps

so, ps

s,p

s.p

vs , vp

s,p

ss.po

s,sp

ss,ps

s.ps

s,p

s.ps

ss,ps

ss, ps

so, po

so,ps

s,p

vs, vp

vs, vp

s,p

vs.vp

ss.ps

so, po

so,po

--

so,ps

s.p

vs , vp

s, vp

s.P

s.p

ss.po

so,po

0

Inpf

Inpf

0

0

0

0

0

0

0

0

0

Inpf

2mkpf

Inpf

0

0

0

0

__2

0

0

0

0

0

0

0

0

3npf

3mkpf

2npf

0

0

0

0

0

0

3npf

3mkpf

2npf

Inpf

0

0

0

6.7

7.2

7.4

7.5

7.8

7.8

7.8

8.0

8.0

8.0

0

6.4

6.7

7.4

8.0

8.0

8.3

8.5

8.7

7.4

7.3

7.4

7.4

7.6

7.9

8.1

8.4

7.5

7.5

7.8

7.9

7.9

8.3

8.6

6.6

6.9

7.0

7.4

7.9

7.9

8.9

8.9

8.6

6.8

6.8

7.1

7.4

7.5

7.6

7.9

8.2

SL

LS

LS

LS

LS

S

S

LS

S

LS

S

SL

SL

SL

SL

LS

LS

S

S

SL

SL

SL

LS

LS

LS

LS

SL

SL

SL

LS

LS

S

S

S

SL

SL

SL

SL

LS

S

S

S

S

--

SL

SL

SL

LS

LS

S

S

S

Wet con- Stage 

sistence CaC03

so, po

so,po

so, po

so^po

so, po

so,po

so, po

so,po

so,po

so,po

so,po

so.po

so, po

so, po

so,po

so.po

so, po

so.po

so,po

so,po

so, po

so,po

so,po

so, po

so,po

so, po

s.sp

so, po

SO,pO

so,po

so.po

so, po

so,po

so, po

so,po

so, po

so,po

so,po

so,po

so.po

so,po

so, po

so,po

__ 

so,po

so, po

so,po

so,po

so.po

so,po

so,po

so,po

0

I

I

II

III

II

I

II

I

II

I

0

0

I

II

III

11+

III

II

II

II

11+

III

11+

II

II

II

II

II

11+

III

11+

I

0

0

0

I

II

III

11+

II

I

0

0

II

II

III

11+

II

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D39
Supplementary table 1, part 2. Field descriptions Continued

Grade

m, massive

sg, single grained

1. weak

2. moderate

3. strong

KEY

SOIL STRUCTURE

Size

vf, very fine (v thin)

f, fine (thin)

m, medium

c, coarse (thick)

vc, very coarse

(very thick)

Type

gr, granular

pi, platey

pr, prismatic

cpr, columnar

abk, angular blocky

sbk, subangular blocky

If two structures, listed as primary and secondary

SOIL TEXTURE

vsg, very slightly

gravelly «5%) 

sg, slightly gravelly

(5-20%)

g, gravelly (20-50%) 

vg, very gravelly (>50%)

co, coarse

f, fine

vf, very fine

S, sand

LS, loamy sand

SL, sandy loam

L, loam

SiL, silt loam

Si, silt

SCL, sandy clay loam

CL, clay loam

SiCL, silty clay loam

SC, sandy clay

C, clay

SIC, silty clay

SOIL CONSISTENCE

so, non-sticky

ss, slightly sticky

s, sticky

vs, very sticky

po, non-plastic

ps, slightly plastic

p, plastic

vp, very plastic

Distinctness

va, very abrupt 

a, abrupt 

c, clear 

g, gradual 

d, diffuse

Topography

w ,

smooth

wa vy 

i, irregular 

b, broken

HORIZON BOUNDARIES

Frequency

v,, very few

1. few

2. common

3. many

4. continuous

CLAY FILMS

Thickness Morphology

n, thin pf, ped face coatings

mk, moderately br, bridging grains

thick po, pore linings

k, thick (w, occurs as waves or lamellae)

co, coats on clasts

STAGES OF CaCO,

Roman numerals indicate increasing content of CaCO,.

For more detailed information, see Soil Survey Staff (1975) and Birkeland (1984). 

For more detailed information, see Bachman and Machette (1977).

D40 Soil Chronosequences in the Western United States
Supplementary table 2. Physical properties

[Analysts: M.C. Reheis and D.M. Cheney, U.S. Geological Survey. , not measured]

Methods

Bulk density was determined by two different methods (Blake, 1965). Two to four paraffin-coated peds taken from relatively fine 

textured horizons provided mean bulk densities for A, B, K, and some C horizons. Bulk density was measured on many gravelly C horizons in 

the field by weighing an excavated amount of soil and measuring the volume of the hole with water-filled plastic bags. For C horizons not 

measured by either of these methods, bulk density was estimated by comparison to horizons with similar gravel content.

Gravel percent by volume was visually estimated for all horizons. Gravel was separated and weighed from bulk samples of finer 

textured horizons to obtain weight percent of gravel as a check on the visual estimate.

Particle size of the <2-mm fraction was obtained by methods described in Day (1965). All samples were pretreated to remove organic 

matter by gentle heating in a weak solution of hydrogen peroxide. Carbonates were removed from samples by gentle heating in a weak 

solution of sodium acetate. The sand fraction was separated by wet sieving; the dried sand was weighed and dry-sieved to obtain the 

various sand fractions. Silt and clay fractions were obtained by the pipette method except for the dust-trap sample, for which there was 

insufficient material after removal of CaCO.j. Sand was removed from the dust-trap sample by wet sieving, and silt and clay fractions were 

determined on the remaining sediment using the 5000b Sedigraph Analyzer (analyses by R. Kihl, Institute of Arctic and Alpine Research, 

Boulder, Colo.).

No.

1 

2

Age 

(ka)

0 

0

Basal Percent of

Sample depth >2mm Total vco 

No. Horizon (cm) (%) sand sand

RC-R 

RC-M

Channel gravel 

Channel gravel 

98 

91

.82 

.25

49.95 

23.18

CO

sand

29.85 

32.92

med 

sand

11.64 

16.31

<2-mm

6 

16

fi 

sand

.59 

.38

fraction

vfi 

sand

0.78 

2.47

Total 

silt

0.41 

5.50

<2u 

clay

0 

3

.77 

.25

percent of <2-mm

<lp Bulk co 

clay density silt 

(g/cm3 )

0.00 

3.25

0 

3

.41 

.89

med 

silt

0

1

.00 

.01

fraction

vfi co clay fi clay 

silt(2-.05u) «0.5u)

0.00 

0.60 -

Mountain-front chronosequence

3 

4 

5 

6

7 

8

9 

10

11 

12 

13 

14

15 

16 

17 

18

19

20 

21 

22 

23 

24 

25 

26

27 

28 

29 

30 

31 

32

33 

34 

35 

36 

37 

38 

39

40 

41 

42 

43 

44 

45 

46

47 

48 

49 

50 

11

7 

7 

7 

7 

7 

7

20 

20 

20 

20 

20 

20

20 

20 

20 

20

120 

120 

120 

120 

120 

120 

120 

120

120 

120 

120 

120 

120 

120

415 

415 

415 

415 ' 

415 

415 

415

600 

600 

600 

600 

600 

600 

600

600 

600 

600 

600 

ftnn

RC-38 

RC-38 

RC-38 

RC-38 

RC-38 

RC-38

RC-21 

RC-21 

RC-21 

RC-21 

RC-21 

RC-21

RC-15 

RC-15 

RC-15 

RC-15

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31

RC-17 

RC-17 

RC-17 

RC-17 

RC-17 

RC-17

RC-30 

RC-30 

RC-30 

 RC-30 

RC-30 

RC-30 

RC-30

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29

RC-16 

RC-16 

RC-16 

RC-16 

RT.-lft

Al 

2A31 

2A32 

2 AC 

3Clox 

3C2ox

A 

Bit 

B2t 

2B3t 

3Clox 

3C2ox

A 

2B2t 

2B3 

2Cox

Al 

A3 

Bit 

B21t 

B22t 

2B31t 

2B32t 

2 Cox

A 

Bit 

B2t 

B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bit 

2B2t 

2B3t

9T.nv

9 

22 

33 

46 

85 

+ 120

5 

12 

25 

38 

73 

+ 110

8 

23 

43 

+68

8 

19 

32 

54 

81 

123 

145 

+200

9 

20 

31 

50 

122 

+ 136

9 

17 

29 

53 

81 

170 

+250

9 

18 

30 

50 

79 

167 

+260

27 

47 

72 

127

+ 1 07

15 

40 

50 

40 

65 

80

5 

5 

15 

25 

85 

85

5 

60 

70 

80

20 

25 

35 

25 

30 

35 

60 

70

5 

15 

20 

30 

60 

80

10 

20 

20 

35 

35 

40 

60

35 

35 

20 

40 

40 

40 

65

10 

20 

40 

50 

fts

81 

81 

84 

86 

84 

80

54 

54 

51 

65 

94 

96

64 

77 

85 

94

67 

65 

56 

60 

65 

81 

86 

91

49 

51 

55 

66 

83 

86

69

74 

66 

70 

73 

82 

86

65 

70 

63 

64 

72 

81 

84

73 

68 

76 

71

HA

.31 

.93 

.76 

.03 

.82 

.82

.24 

.69 

.61 

.38 

.51 

.70

.84 

.18 

.93

.77

.56 

.92 

.24 

.54 

.06 

.00 

.08 

.84

.38 

.33 

.60 

.93 

.49 

.75

.53 

.74 

.49 

.59 

.55 

.97 

.95

.87 

.19 

.36 

.88 

.64 

.55 

.29

.84 

.11 

.65 

.98

. si

27.83 

34.43 

34.27 

34.39 

29.76 

24.10

10.41 

13.76 

11.99 

17.56 

32.47 

18.52

8.04 

17.71 

24.79 

29.08

24.91 

24.29 

18.78 

21.50 

20.29 

29.16 

30.89 

32.04

6.00 

5.37 

7.50 

11 .42 

14.82 

21 .46

26.28 

33.72 

25.39 

27.89 

27.68 

28.05 

37.99

24.65 

26.08 

23.23 

24.58 

29.56 

22.81 

30.52

18.97 

13.72 

16.70 

8.40

1 Q 7B

22.91 

19.15 

20.59 

21.63 

24.64 

24.03

14.61 

12.27 

10.68 

13.52 

31.47 

25.81

15.61 

18.29 

20.74 

29.50

16.19 

14.96 

11.17 

13.10 

15.65 

20.75 

23.56 

27.33

9.27 

7.76 

9.94 

15.31 

27.04 

24.72

18.01 

17.65 

15.48 

17.37 

19.67 

25.62 

28.69

16.09 

18.17 

15.36 

15.36 

16.42 

23.64 

24.65

20.13 

16.73 

21.19 

13.35

12.59 

10.48 

11.37 

11.40 

11.99 

12.31

9.23 

8.52 

7.93 

10.37 

16.18 

22.95

17.95 

19.97 

21.62 

22.55

9.32 

8.81 

7.26 

7.29 

9.92 

11.60 

12.49 

14.10

11.00 

11.22 

12.56 

15.91 

23.50 

20.73

9.52 

8.95 

8.80 

8.70 

10.53 

13.19 

9.66

9.06 

9.63 

8.41 

8.56 

9.21 

12.59 

12.61

16.5 

15.38 

19.03 

19.79

99 -\C\

15 

13 

14 

14 

14 

15

15 

14 

15 

18 

12 

25

13 

13 

13 

13 

14 

15 

15 

14

12 

11 

12 

12 

12 

13 

8

12 

12 

12 

12 

13 

16 

13

.09 

.69 

.58 

.73 

.44 

.61

.14 

.85 

.17 

.66 

.46 

.59

.70 

.46 

.47 

.52 

.48 

.00 

.12 

.88

.07 

.00 

.45 

.61 

.40 

.26 

.54

.12 

.60 

.23 

.07 

.27 

.96 

.72

2.86 

4.18 

3.95 

3.88 

4.00 

4.77

4.84 

5.28 

5.85 

5.27 

1.93 

3.82

3.45 

4.40 

5.57 

5.13 

4.72 

4.49 

4.02 

3.50

3.66 

3.42 

4.38 

4.02 

3.27 

2.84 

2.07

3.95 

3.71 

4.15 

4.30 

4.18 

5.55 

2.79

15.32 

14.32 

12.30 

11 .79 

13.46 

16.84

33.25 

31.45 

31.11 

20.70 

4.70 

2.77

3.57

21.58 

22.52 

27.61 

24.71 

16.52 

12.18 

9.59 

5.94

32.69

20.25 

16.22 

21.50 

13.11 

11 .16 

6.41 

4.91

22.88 

19.07 

22.10 

20.91 

16.62 

11.23 

5.64

14.47

A m

3 

3

2 

2

1 

2

12 

13 

17 

13 

0 

0

10 

11 

16 

14 

18 

6 

4 

2

10 

9 

12 

16 

15 

10 

8

11 

10 

14 

14 

10 

7 

10

.37 

.75 

.94 

.18 

.72 

.34

.51 

.86 

.28 

.92 

.79 

.53

.86 

.56 

.15 

.75 

.42 

.82 

.33 

.22

.22 

.04 

.01 

.30 

.29 

.62 

.14

.25 

.74 

.54 

.21 

.74 

.22 

.07

3.11 

3.05 

2.94 

2.18 

1.49 

2.34

10.37 

11.24 

15.21 

12.97 

0.79 

0.53

1.81 

9.64 

15.06 

13.02 

16.95 

6.29 

4.17 

1.84

6.65 

8.65 

11.37 

15.53 

15.14 

10.62 

7.92

9.83 

10.62 

13.24 

13.29 

10.37 

6.93 

9.85

1.18 

1.75 

1.50 

1.50 

1.90 

1.80

1.47 

1.65 

1.60 

1.74 

1.80 

1.80

1.31 

1.53 

1.69 

1.82 

1.78 

1.97 

1.94 

1.94

1.26 

1.60 

1.58 

1.82 

1.85 

1.93 

1.84

1.26 

1.52 

1.60 

1.75 

1.74 

2.06 

1.88

8 

8 

7 

7 

8 

10

17 

16 

16 

10 

3 

2

13 

12 

16 

15 

9 

7 

5 

4

11 

8

13 

8 

5 

4 

3

12 

10 

12 

12 

9 

6 

3

.45 

.61 

.94 

.47 

.81 

.27

.18 

.29 

.88 

.88 

.59 

.50

.01 

.86 

.45 

.16 

.92 

.32 

.77 

.11

.99

.15 

.65 

.88 

.74 

.08 

.16

.07 

.33 

.54 

.18 

.62 

.95 

.74

4 

4 

3 

3 

3 

5

11 

10 

10

7 

0 

0

7 

8 

9 

7 

6 

4 

3 

1

6 

6 

4 

4 

3

o0

7 

5 

6 

6 

4 

3 

0

.88 

.06 

.22 

.20 

.35 

.06

.52 

.98 

.37 

.04 

.78 

.27

.34 

.23 

.13 

.83 

.05 

.52 

.62 

.83

.14 

.17 

.57 

.12 

.69 

.92 

.90

.81 

.52 

.59 

.02 

.00 

.13 

.94

1.98 

1.65 

1.14 

1.13 

1.30 

1.51

4.55 

4.18 

3.86 

2.78 

0.34 

0.00

1.23 

1.43 

2.03 

1.73 

0.55 

0.34 

0.20 

0.00

2.12 

1.90 

3.29 

0.12 

1.73 

1.40 

0.85

2.99 

3.23 

2.96 

2.71 

3.01 

1.14 

0.96

3.71 6.31 

2.49 5.13 

1.56 3.25 

0.56 1.10

5.27 12.66 

6.01 14.78 

4.92 15.37 

3.73 13.50 

1.27 4.57 

1.28 2.56

2.82 8.87 

3.21 13.79 

1.71 12.51 

3.50 12.64 

1 .61 1.81

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D41
Supplementary table 2. Physical properties Continued

No.

52 

53 

54 

55 

56 

57

58 

59 

60 

61 

62 

63

Age 

(ka)

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Basal Percent of

Sample depth >2mmTotal 

No. Horizon (cm) (%)sand

RC-28 

RC-28 

RC-28 

RC-28 

RC-28 

RC-28

RC-14 

RC-14 

RC-14 

RC-14 

RC-14 

RC-14

A 

Bit 

B2t 

2B31 1 

2B32t 

2Cox

A 

Bit 

B2t 

2B31t 

3B32t 

3 Cox

7 

11 

17 

47 

141 

+ 270

17 

32 

44 

84 

144 

+ 164

30 

20 

25 

60 

60 

70

5 

5 

10 

40 

50 

70

73.32 

77.03 

74.17 

76.66 

83.22 

89.55

56.46 

55.84 

60.02 

72.86 

81.19 

89.29

vco 

sand

31.84 

32.11 

28.22 

26.65 

28.56 

27.65

9.32 

9.96 

12.29 

13.47 

20.61 

18.11

CO

sand

18.29 

19.27 

19.08 

21.91 

28.27 

31.38

13.99 

12.62 

14.66 

20.53 

26.97 

31.20

med 

sand

8.54 

9.79 

10.09 

9.90 

12.07 

17.49

12.49 

11.73 

12.49 

17.93 

18.94 

24.19

<2-mm fraction

fi vfi 

s a nd s a nd

11 .10 

12.09 

12.86 

13.93 

11 .44 

11.36

3.55 

3.83 

3.92 

4.28 

2.89 

1.67

Total 

silt

17.88 

13.99 

14.20 

12.07 

7.63 

3.59

25.01

7.54

6.09

clay

8.80 

8.98 

11 .63 

11.27 

9.15 

6.86

percent of <2-mm

<ly Bulk co 

clay density silt 

(g/cm3 )

8.27 

8.20 

10.70 

10.00 

8.18 

6.55

1.26 

1.53 

1.64 

1.88 

1.98 

1.93

1.52

1.79

9.64 

6.90 

7.95 

6.76 

4.16 

1.81

med 

silt

5.79 

5.49 

4.53 

4.08 

2.82 

1.56

fraction

vfi co clay 

silt(2-.05u)

2.46 

1.55 

1.73 

1.23 

0.66 

0.22

5.35 

5.88 

4.53 

2.57 

1.70 

0.98

fi clay 

«0.5y)

13.18 

15.52 

15.75 

11.65 

9.57 

3.64

Transition chronosequence

64 

65 

66 

67

68 

69 

70 

71 

72

73 

74 

75 

76 

77 

78 

79 

80

81 

82 

83 

84 

85

86 

87 

88 

89

90 

91 

92 

93 

94 

95

96 

97 

98 

99 

100

101 

102 

103 

104 

105 

106 

107

108 

109 

110 

111 

112 

113 

114 

115

7 

7 

7

7

7 

7 

7 

7 

7

20 

20 

20 

20 

20 

20 

20 

20

120 

120 

120 

120 

120

120 

120 

120 

120

120 

120 

120 

120 

120 

120

415 

415 

415 

415 

415

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600 

600

RC-40 

RC-40 

RC-40 

RC-40

RC-42 

RC-42 

RC-42 

RC-42 

RC-42

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22

RC-12 

RC-12 

RC-12 

RC-12 

RC-12

RC-32 

RC-32 

RC-32 

RC-32

RC-41 

RC-41 

RC-41 

RC-41 

RC-41 

RC-41

RC-11 

RC-11 

RC-11 

RC-11 

RC-11

RC-37 

RC-37 

RC-37 

RC-37 

RC-37 

RC-37 

RC-37

RC-34 

RC-34 

RC-34 

RC-34 

RC-34 

RC-34 

RC-34 

RC-34

A 

Bs 

2Clox 

2C2ox

Al 

A3 

2Bs 

3Bb 

3Coxb

A 

Bit 

B2t 

2B3t 

2Clox 

2C2ox 

3Cca 

3Cn

A 

Bit 

B2t 

2B3t 

2 Cox

Ap 

2B2tca 

2B3tca 

3Cca

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

A 

B2t 

B3t 

2Clca 

2C2ca

A 

Bit 

B2tca 

B3tca/K 

2Clca 

3C2ca 

3C3ca

Al 

A3 

Bit 

B2t 

2B3t/ca 

3Cox/ca 

3Clca 

3C2ca

13 

46 

75 

310

6 

37 

55 

73 

+ 200

5 

25 

43 

57 

78 

175 

197 

+240

9 

17 

39 

62 

+122

21 

37 

70 

+80

8 

17 

28 

51 

65 

+ 100

9 

20 

50 

100 

+ 180

6 

18 

45 

63 

109 

230 

+ 240

8 

14 

22 

37 

54 

89 

160 

+210

5 

30 

70 

75

30 

40 

10 

50 

75

5 

20 

35 

75 

75 

60 

80 

80

5 

15 

25 

50 

80

5 

40 

15 

80

20 

30 

30 

45 

65 

80

30 

40 

40 

60 

80

5 

20 

15 

5 

45 

70

10 

10 

10 

20 

50 

60 

80 

80

59.32 

62.08 

88.39 

93.45

58.17 

61 .32 

62.92 

66.02 

93.59

50.81 

55.00 

55.06 

75.67 

84.85 

84.04 

88.62 

90.37

47.07 

42.73 

66.74 

76.45 

89.36

22.06 

54.40 

59.59 

87.37

54.73 

46.80 

44.76 

70.76 

75.93 

91.95

70.31 

63.20 

76.46 

81.70 

95.49

56.39 

49.70 

57.88 

49.32 

59.42 

88.55

52.77 

54.04 

52.53 

50.22 

74.45 

84.14 

93.01 

95.45

1.74 

4.19 

6.12 

5.74

4.17 

5.33 

5.72 

8.69 

26.48

7.68 

10.57 

10.60 

26.00 

27.23 

24.91 

36.30 

9.65

7.21 

5.81 

17.61 

21.59 

23.33

4.13 

19.21 

15.88 

26.72

13.56 

12.39 

13.77 

30.19 

36.45 

47.70

10.46 

11.83 

23.50 

20.05 

5.07

9.76 

6.52 

5.31 

3.65 

14.68 

18.29

15.88 

16.33 

15.15 

16.09 

31.65 

23.35 

33.53 

29.69

6.30 

9.57 

25.26 

39.14

11.91 

13.08 

12.92 

19.67 

33.73

14.16 

16.23 

18.05 

24.88 

28.24 

25.38 

28.06 

27.58

11.17 

9.09 

23.12 

26.51 

33.53

3.97 

16.26 

16.47 

37.86

11.87 

9.53 

9.52 

18.93 

22.48 

34.26

18.81 

17.21 

23.28 

22.79 

40.44

13.59 

10.51 

9.94 

14.79 

19.50 

39.94

13.15 

13.85 

13.25 

11.40 

17.03 

24.81 

32.80 

41.79

12.58 

14.26 

42.74 

36.48

10.92 

11.52 

11.13 

12.50 

18.67

8.08 

8.81 

9.52 

11.00 

14.28 

16.84 

11.45 

20.08

9.38 

9.97 

14.15 

16.34 

21.88

3.28 

7.69 

9.97 

13.34

7.13 

6.43 

6.49 

8.94 

8.03 

6.43

18.92 

16.32 

15.86 

22.00 

39.10

10.58 

9.90 

12.08 

9.39 

9.57 

17.60

7.42 

7.67 

7.67 

6.51 

8.46 

13.90 

12.37 

14.50

22.85 

23.61 

24.25 

18.27 

13.02

14.63 

13.96 

11.90 

10.89 

12.81 

14.54 

10.49 

27.01

7.61 

8.66 

13.49 

8.12

15.01 

12.87 

10.98 

9.90 

6.88 

2.83

16.83 

17.53 

23.90 

15.45 

11.74 

10.86

11.20 

11.31 

11.45 

10.86 

12.67 

17.14 

11.84 

8.43

8.32 

7.78 

8.89 

6.89 

1.69

6.27 

5.43 

4.98 

2.91 

2.29 

2.38 

2.33 

6.06

3.06 

2.58 

3.78 

1.32

7.15 

5.59 

4.00 

2.79 

2.10 

0.74

5.63 

5.24 

6.66 

6.05 

3.94 

1.86

5.12 

4.88 

5.02 

5.36 

4.65 

4.94 

2.48 

1.03

32.95 

29.68 

26.95 

24.07 

4.32

36.40 

31.96 

28.63 

14.90 

8.43 

10.21 

7.29 

6.80

31.35 

18.83 

20.63 

7.17

34.69 

33.21 

21.87 

7.35 

6.94 

1.67

29.53 

30.67 

21.05 

21.16 

21.35 

6.21

32.09 

31.63 

32.19 

29.45 

15.30 

11.48 

4.73 

2.22

8.88 

9.00 

10.13 

9.91 

2.09

12.79 

13.04 

16.31 

9.43 

6.72 

5.75 

4.09 

2.83

46.59 

26.77 

19.78 

5.46

10.58 

19.99 

33.37 

21 .89 

17.13 

6.38

14.08 

19.63 

21 .07 

29.52 

19.23 

5.24

15.14 

14.33 

15.28 

20.33 

10.25 

4.38 

2.26 

2.33

7.71 

7.36 

8.31 

7.94 

1.85

9.95 

10.58 

14.16 

7.99 

6.21 

5.72 

4.09 

2.54

41.49 

24.19 

17.76 

4.31

7.28 

14.67 

30.38 

21.69 

15.89 

6.12

11.96 

17.75 

19.95 

28.80 

19.23 

5.24

11.78 

13.18 

14.15 

20.32 

10.25 

4.38 

2.26 

2.23

1.48

1.44 

1.45 

1.48 

1.50 

1.88

1.35 

1.52 

1.75 

1.69 

1.80 

1.88 

2.11 

1.80

1.70 

1.67 

1.62 

1.85

1.33 

1.73 

1.64 

1.75 

1.90 

1.85

1.35 

1.63

1.71 

1.23 

1.49 

1.94

1.61 

1.61 

1.64 

1.67 

1.83 

1.74 

1.85 

1.88

22.85 

20.37 

17.95 

15.82 

3.11

22.45 

18.98 

16.18 

8.99 

5.56 

4.73 

3.76 

5.47

13.55 

7.62 

11.93 

3.96

21.84 

17.31 

12.60 

5.29 

4.82 

1.04

16.51 

17.03 

12.48 

14.48 

12.80 

3.56

19.89 

18.66 

19.13 

18.02 

9.53 

7.41 

3.03 

1.81

7.67 

6.25 

4.09 

5.93 

0.76

9.68 

9.46 

9.20 

5.03 

2.61 

4.47 

3.04 

1.22

10.15 

8.21 

6.14 

2.08

9.57 

11.11 

6.80 

1.88 

0.89 

0.00

7.71 

9.39 

5.50 

3.72 

5.67 

1.20

10.01 

9.47 

9.93 

7.91 

4.38 

3.30 

1.06 

0.31

2.43 

3.07 

4.91 

2.31 

0.45

4.27 

3.52 

3.26 

0.88 

0.26 

1.00 

0.48 

0.10

7.65 

3.01 

2.55 

1.13

3.28 

4.79 

2.47 

0.19 

1.24 

0.64

5.31 

4.25 

3.07 

2.95 

2.88 

1.45

2.19 

3.50 

3.14 

3.53 

1.38 

0.77 

0.63 

0.10

4.43 

4.40 

0.59 

0.26

7.45 

7.82 

3.12 

2.81 

0.82

3.44 

3.51 

1.99 

1.68 

0.79

~

9.57 

10.34 

6.30 

3.27

11.73 

21.54 

22.68 

14.49 

6.63

9.36 

21.79 

13.71 

7.38 

1.80

-

D42 Soil Chronosequences in the Western United States
Supplementary table 2. Physical properties Continued

Age 

No. (ka)

116 600 

117 600 

118 600 

119 600 

120 600 

121 600 

122 600 

123 600

124 945 

125 945 

126 945 

127 945 

128 945

129 945 

130 945 

131 945 

132 945 

133 945 

134 945 

135 945 

136 945 

137 945 

138 945 

139 945

140 2,000 

141 2,000 

142 2,000 

143 2,000 

144 2,000 

145 2,000 

146 2,000 

147 2,000 

148 2,000

149 2,000 

150 2,000 

151 2,000 

152 2,000 

153 2,000

154 7 

155 7 

156 7 

157 7 

158 7

159 7 

160 7 

161 7

162 20 

163 20 

164 20 

165 20 

166 20 

167 20

168 20 

169 20 

170 20 

171 20 

172 20 

173 20

174 120 

175 120 

176 120 

177 120 

178 120 

179 120 

i Rn 1 9n

Basal Percent of

Sample depth >2mmTotal 

No. Horizon (cm) (%)sand

RC-35 A 

RC-35 Bit 

RC-35 B2tca 

RC-35 B3tca 

RC-35 2Clca 

RC-35 2C2ca 

RC-35 2C3ca 

RC-35 2C4ca

RC-6 A 

RC-6 Bit 

RC-6 B2t 

RC-6 2Clca 

RC-6 2C2ca

RC-36 A 

RC-36 Bl t 

RC-36 B2tca 

RC-36 B3tca 

RC-36 K 

RC-36 2Clca 

RC-36 3C2ca 

RC-36 3C3ca 

RC-36 3C4ca 

RC-36 4C5ca 

RC-36 4C6ca

RC-33 Al 

RC-33 A3 

RC-33 Bit 

RC-33 B2t 

RC-33 2B3t/ca 

RC-33 2K1 

RC-33 2K2 

RC-33 3Clca 

RC-33 3C2ca

RC-8 A 

RC-8 B2t 

RC-8 283 tea 

RC-8 2K 

RC-8 2Cca

RC-46A Ap 

RC-46A ACca 

RC-46A 2Cgca 

RC-46A 2 Cox 

RC-46A 3Cn

RC-46B Apca 

RC-46B 2Cca 

RC-46B 3Cn

RC-20 A 

RC-20 281 t 

RC-20 282 tea 

RC-20 283 tea 

RC-20 3Clca 

RC-20 3C2ca

RC-43 A 

RC-43 Bit 

RC-43 B2t 

RC-43 283 tea 

RC-43 2Clca 

RC-43 3C2ca

RC-27 A 

RC-27 28 It 

RC-27 2B2t 

RC-27 3B3ca 

RC-27 3Clca 

RC-27 4C2ca

5 

10 

18 

32 

54 

135 

225 

+235

13 

30 

46 

96 

+ 126

7 

16 

25 

35 

53 

80 

103 

173 

200 

227 

+ 255

9 

16 

24 

43 

58 

58 

92 

180 

+220

8 

22 

72 

112 

+ 162

20 

40 

70 

98 

+ 150

28 

60 

+ 150

9 

15 

32 

50 

130 

+ 330

18 

33 

44 

65 

98 

+200

6 

11 

19 

34 

74 

147 

-1.99 1;

5 

10 

20 

20 

70 

75 

80 

80

5 

10 

20 

60 

75

35 

25 

35 

5 

10 

75 

15 

5 

5 

75 

85

45 

30 

20 

5 

45 

45 

45 

70 

80

20 

25 

50 

60 

60

0 

0 

0 

0 

85

5 

30 

85

5 

5 

35 

35 

75 

85

5 

5 

5 

65 

60 

80

5 

55 

65 

0 

0 

5 

f,n

62.28 

56.13 

58.75 

80.25 

85.34 

82.78 

93.11 

94.05

52.56 

53.84 

52.83 

83.20 

93.01

50.20 

49.62 

53.06 

47.07 

33.95 

40.66 

21.83 

8.44 

41.19 

80.10 

82.31

45.02 

38.85 

33.66 

35.89 

48.48 

71.00 

73.95 

76.91 

76.12

49.64 

51.94 

62.14 

78.18 

72.85

23.03 

56.25 

26.30 

45.82 

85.38

26.07 

55.39 

85.38

50.12 

47.87 

65.05 

83.36 

89.60 

94.34

31.12 

44.29 

40.06 

71.33 

91.82 

95.95

39.14 

45.39 

37.51 

42.98 

42.10 

46.55

77 . 77

VCO

sand

8.11 

8.18 

8.44 

18.15 

31.49 

8.40 

8.12 

6.63

2.25 

3.40 

3.12 

21.59 

10.21

5.84 

5.44 

3.41 

3.33 

2.72 

6.57 

0.72 

0.21 

0.69 

18.83 

30.13

17.74 

12.84 

10.91 

12.56 

16.95 

22.30 

30.33 

25.06 

19.65

12.29 

15.06 

14.23 

6.06 

3.52

0.05 

0.00 

0.00 

0.00 

26.01

0.31 

5.39 

26.01

3.65 

3.48 

17.51 

19.93 

16.80 

15.40

0.38 

3.44 

2.79 

15.76 

11.05 

12.34

0.35 

4.74 

7.74 

1.72 

0.45 

0.40

T 1 Q

CO

sand

11.13 

8.70 

8.22 

20.26 

20.49 

20.99 

20.49 

25.93

5.77 

7.55 

6.90 

22.75 

35.68

8.41 

7.34 

7.01 

5.21 

2.82 

3.93 

1.47 

0.49 

3.31 

24.78 

26.01

10.34 

9.58 

8.24 

8.83 

11.94 

18.73 

19.97 

22.94 

21 .40

13.46 

16.20 

17.66 

12.58 

7.62

0.05 

0.05 

0.05 

0.05 

24.94

0.77 

6.11 

24.94

7.91 

5.81 

15.15 

25.81 

17.73 

33.99

1.78 

8.01 

8.12 

22.72 

36.48 

37.98

0.67 

3.16 

4.10 

3.36 

2.55 

0.49 

7 <;n

<2-mm fraction

med fi vfi 

sand sand sand

17.16 

15.72 

15.92 

20.33 

18.32 

28.08 

41.51 

40.56

12.87 

14.72 

13.83 

18.76 

35.46

8.71 

9.73 

10.47 

7.87 

3.51 

2.79 

2.28 

0.61 

6.99 

16.38 

11.82

5.15 

5.05 

4.44 

4.80 

6.69 

11.22 

9.86 

12.81 

13.44

10.61 

10.22 

14.00 

18.98 

16.70

Basin

0.72 

2.28 

0.64 

1.68 

12.48

1.45 

5.08 

12.48

7.87 

7.92 

9.04 

16.61 

21.97 

20.24

3.19 

5.88 

7.04 

12.69 

23.11 

27.08

2.55 

4.19 

2.88 

5.60 

0.74 

1.61

9T 1A

~

-

21.27 5.98 

21.89 5.22 

25.61 6.55 

22.63 8.02 

16.73 8.18 

17.85 9.52 

10.62 6.74 

3.54 3.59 

19.25 10.95 

16.09 4.03 

11.83 2.52

8.27 3.52 

8.14 3.25 

7.34 2.74 

7.26 2.44 

9.83 3.08 

14.76 4.00 

10.90 2.88 

13.31 2.78 

17.71 3.92

Total 

silt

24.79

15.50

10.50

33.21 

18.39 

19.88 

28.72 

36.29 

36.01 

45.15 

50.95 

38.09 

12.95 

11.27

31.13 

27.84 

27.30 

23.38 

23.64 

13.64 

11.66 

7.98 

8.60

13.77

<2y 

clay

-

-

16.59 

31.99 

27.06 

24.21 

29.76 

23.33 

33.02 

40.61 

20.72 

6.95 

6.42

23.85 

33.31 

39.04 

40.73 

27.88 

15.36 

14.39 

15.11 

15.28

percent of <2-mm

<ly Bulk CO 

clay density silt 

(g/cm3 )

~

-

13.48 

29.13 

25.06 

22.01 

25.19 

19.43 

26.92 

33.05 

17.69 

5.64 

5.38

20.38 

30.80 

36.97 

40.25 

26.70 

15.36 

13.69 

15.11 

11 .67

1.39

1.53

1 to

1.63

1.41 

1.48 

1.57 

1.56 

1.53 

1.48 

1.58 

1.67 

1.67 

1.85 

1.85

1.42 

1.53 

1.60 

1.58 

1.49 

1.49 

1.71 

1.85 

1.84

-

-

21.10 

9.52 

10.92 

17.59 

20.96 

20.84 

25.19 

23.67 

23.32 

8.49 

6.73

15.79 

13.62 

13.32 

10.55 

12.12 

8.39 

6.31 

4.75 

4.98

med 

silt

-

-

8.47 

6.65 

6.64 

7.90 

10.39 

10.06 

13.20 

17.59 

10.25 

1.12 

2.48

10.01 

9.19 

8.62 

9.33 

7.10 

3.61 

3.82 

2.07 

2.93

fraction

vfi co clay 

silt(2-.05y)

-

-

-

3.64 

2.22 

2.32 

3.23 

4.95 

5.11 

6.76 

9.69 

4.53 

3.35 

2.06

5.33 

5.03 

5.35 

3.49 

4.42 

1.63 

1.53 

1.17 

0.69

3.88 

4.54 

3.75 

1.04 

1.36 

1.39 

0.44 

0.65

5.61 

4.21 

3.64 

1.77 

0.85

8.85 

5.60 

5.00 

2.11 

2.12

fi clay 

«0.5y)

9.05 

17.81 

22.00 

9.03 

5.59 

4.94 

0.67 

0.65

13.95 

19.12 

20.82 

4.53 

1.07

21.19 

28.86 

19.09 

2.11 

0.92

chronosequence

22.16 8.53 

22.91 7.75 

18.28 5.07 

17.90 3.11 

29.51 3.60 

21.26 3.45

15.34 10.43 

15.45 11.52 

15.08 7.02 

15.41 4.74 

18.86 2.33 

16.68 1.86

-

__

35.53

44.33

34.11

33.09 

24.49 

14.02 

9.27 

5.25 

3.43

41.11 

38.24 

28.13 

17.02 

4.84 

2.65

36.07

20.79

34.44 

43.22 

i f. (,*,

16.79 

27.64 

20.93 

7.37 

5.15 

2.23

27.77 

17.47 

31.81 

11.65 

3.34 

1.40

~

~

15.16 

27.08 

20.91 

6.87 

5.12 

2.23

25.43 

14.94 

30.91 

10.89 

3.09 

1.40

-

1.50

1.58 

1.65 

1.75 

1.63 

1.85 

1.80

1.52 

1.52 

1.54 

1.49 

1.94 

1.85

1.45

1.41

1.30 

1.60 

1.55

1 RR

22.74 

15.82 

9.08 

5.30 

3.34 

2.35

28.64 

26.81 

20.08 

11.91 

3.28 

1.92

-

6.74 

5.74 

3.63 

2.88 

1.53 

0.35

8.73 

8.24 

5.36 

3.89 

1.56 

0.73

~

-

3.61 

2.93 

1.31 

1.09 

0.37 

0.73

3.75 

3.18 

2.69 

1.22 

0.00 

0.00

-

8.03 

3.52 

8.54 

3.09 

1.55

7.51 

3.32 

1.55

10.34 

6.89 

6.32 

7.03 

5.55 

6.14

7 . AQ

20.13 

4.70 

20.83 

7.32 

2.85

18.65 

7.18 

2.85

14.45 

17.22 

35.38 

16.21 

17.91 

4.09

9 .«Q

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D43
Supplementary table 2. Physical properties Continued

No.

Age 

(ka)

Basal Percent of

Sample depth >2mm Total 

No. Horizon (cm) ( 30 sand

vco 

sand

CO

sand

med 

sand

<2-ram fraction

fi vfi 

sand sand

Total 

silt

<2u 

clay

percent of <2-nm

<l]j Bulk co 

clay density silt

(g/cmj;

181

182

183

184

185

186

187

188

199

190

191 

192

193

194

195

196

197

198

199 

200

201 

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223 

224

225 

226

227

229

230

231

415

415

415

415

415

415

415

415

415

415

415 

600

600

600

600

600

600

600

600 

945

945 

945

945

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000 

2,000

2,000 

2,000

2,000

2,000

2,000

2,000

2,000

RC-23 A

RC-23 Bltca

RC-23 B2tca

RC-23 B3tca

RC-23 2K

RC-23 3Clca

RC-23 3C2-ca

RC-23 4C3ca

RC-23 5C4ca

RC-23 5C5ca

RC-23 5C6ca 

RC-24 A

RC-24 Bit

RC-24 B2tca

RC-24 B3tca

RC-24 K

RC-24 2Clca

RC-24 2C2ca

RC-24 2C3ca 

RC-25 Aca

RC-25 Bltca 

RC-25 B2tca

RC-25 B3tca

RC~25 2K

RC-25 2Clca

RC-25 2C2ca

RC-25 3C3ca

RC-44 Aca

RC-44 Bltca

RC-44 B21 tea

RC-44 B22tca

RC-44 2B31tca

RC-44 2B32tca

RC-44 2Cca

RC-26A A

RC-26A Bit

RC-26A B21t

RC-26A B22tca

RC-26A B3tca

RC-26A 2K

RC-26A 2Clca

RC-26A 2C2ca

RC-26A 3C3ca 

RC 26B A

RC-26B Bit 

RC-26B B2tca

RC-26B B31tca

RC-26B B32tca

RC-26B 2K

RC-26B 2Clca

RC-26B 2C2ca

3

7

14

29

60

121

170

226

255

310

+320 

4

9

19

30

45

62

87

+ 300 

4

9

15

25

49

65

91

+ 130

6

13

19

27

45

86

+ 120

6

11

20

29

40

68

145

247

295 

5

10 

16

25

36

48

88

+ 170

5

25

40

35

55

85

85

50

80

80

5

10

5

5

15

70

80

80 

15

15

15

50

55

60

75

20

15

15

30

30

55

80

85

20

25

5

15

15

45

75

65

60 

5

15 

5

5

15

45

60

70

29.12

38.28

36.93

56.72

80.31

64.23

83.65

74.51

89.07

84.98

24.20

22.11

17.74

22.56

35.02

69.06

88.54

97.40 

45 .22

41.38

43 .28 

49.18

69.80

76.35

86 .58 

74.46

35.19

28.51

27.35

35.86

40.17

70.94

85.47

45.57

38.78

36.31

39.21

42.85

70.28

82.21

91.36

94.06 

55.43

44.19 

41.19

44.45

57.66

76.51

83.28

91.33

5.40

8.18

7.68

20.78

32.05

13.83

14.42

14.50

25.80

22.48

3.30

2.88

1.34

2.35

4.81

17.28

14.57

4.05 

5.69

4.56

5.48

8 

QQ77

20.16

12.43

12.13

12.47 

3.86

3.32

2.69

4.71

9.06

14.76

10.87

14.00

10.55

9.37

9.85

10.48

19.29

19.90

30.12

24.24 

10.35

6.53

5 no »Uo 

7.20

14.11

21.95

14.89

2.41

4.77

6.02

6.59

12.54

19.96

16.93

24.49

30.85

35.32

26.89

3.12

2.78

1.66

2.15

5.91

17.59

25.82

37.14

5.79 

3.85

4.41

7.03

13 86

15.66

16.47

10.66 

3.71

2.84

2.75

4.27

7.15

13.40

15.53

9.55

7.99

7.40

7.91

9.45

17.71

24.23

35.93

50.00 

11.22

7.57 

6.54

7.88

12 .67

19.38

22.42

9.69

2.61

3.05

3.94

6.03

9.57

10.49

15.90

14.02

12.83

12.48

2.23

2.06

1.36

1.77

5.41

11.77

20.24

34.78

6.86 

5.59

6.15

7 .62

15.11

26 .55

33.72

19.83 

3.10

2.39

2.46

3.81

4.83

11.61

19.54

4.75

4.67

4.46

4.81

5.63

12.39

14.13

12.94

12.51

9.11 

7.85

7.40 

7.77

11.15

17.87

27.71

32.05

8.27

9.61

11.00

11.23

14.36

16.97

22.75

11.88

12.10

17.89

7.06

6.60

5.44

7.26

13.05

17.07

22.98

19.95

-

15.87

12.36

11 .93

15.47

13.74

24.75

33.04

11.13

9.89

9.57

10.09

11.35

16.78

19.36

10.44

6.26

-

_

_

8.08

11.41

7.73

6.13

4.38

6.01

6.10

3.26

3.02

5.24

8.48

7.80

7.94

, 9.03

5.84

5.36

4.93

1.47

-

8.64

7.60

7.52

7.60

5.39

6.41

6.49

6.14

5.68

5.51

6.55

5.94

4.11

4.59

1.93

1.06

-

_

_

52.52

45.98

40.34

27.91

13.05

20.68

10.80

18.95

6.56

11.49

45.33

43.83

45.06

51.40

35.60

17.14

8.42

2.10

38 .65 

35.40

33 .66

30.04

17.20

15 .68

10.24

18 88 

39.25

36.27

38.86

39.91

37.19

22.61

12.46

42.59

35.49

37.23

35.57

32.07

15.06

13.78

6.20

4.18

30.49 

29.05

28.74 

29.88

23 .37 

12.96

10.72

7.64

18.36

15.74

22.73

15.37

6.64

15.09

5.55

6.54

4.37

3.53

30.47

34.06

37.20

26.04

29.38

13.80

3.04

0.50

-

25.56

35.22

33.79

24.23

22.64

6.45

2.07

11.84

25.73

26.46

25.22

25.08

14.66

4.01

2.44

1.76

-

_

16.10

13.03

19.82

14.08

5.82

12.00

4.04

4.93

3.54

3.31

27.83

31.69

33.90

22.80

27.12

10.64

2.32

0.29

-

24.75

32.60

30.87

20.52

19.05

5.41

1.96

8.55

22.06

22.99

21.97

20.94

12.59

3.25

1.83

1.65

~

1.24

1.51

1.50

1.55

1.64

1.80

1.85

1.83

1.80

1.80

1.51

1.69

1.40

1.28

1.26

1.80

1.80

1.80 

1.27

1.15

1.17 

1.25

1.50

1.94 

1 ft*; 1 .Qj

1 7ft

1.31

1.40

1.27

1.87

1.33

1.80

1.80

1.57

1.55

1.55

1.50

1.26

1.34

1.89

1.98

1.94 

1.45

1.46 

1.43

1.30

1.33

1.54

1.94

1.88

)

38.49

33.54

30.94

21.59

9.69

10.91

6.25

13.42

4.84

8.10

31.38

30.28

32.31

35.67

22.39

10.60

5.07

0.94

-

25.21

23.50

24.56

27.26

27.02

16.62

9.90

28.39

23.39

25.88

24.06

19.06

9.07

7.64

3.15

2.29

-

_

med 

silt

10.60

9.07

7.19

5.11

2.34

5.56

2.72

4.17

1.08

1.85

9.83

10.58

9.88

11.97

9.37

4.46

2.53

1.17

-

9.96

9.62

11.13

9.41

7.75

5.08

2.57

10.44

9.26

8.60

8.68

10.62

4.77

3.87

1.59

0.30

-

_

fraction

vfi co clay 

si.lt(2-.05y)

3.43

3.38

2.20

1.22

1.02

4.20

1.83

1.36

0.64

1.54

4.12

2.96

2.87

3.75

3.85

2.08

0.81

0.00

-

4.07

3.16

3.16

3.24

2.42

0.91

0.00

3.76

2.83

2.74

2.84

2.38

1.22

2.28

1.45

1.59

-

__

_

_

6.66

6.01 

5.76

5.39

3.75

3.19

1 "*ft 1 JO

3.40

_

5.31

5.79 

5.56

5.02

4.40

2.97

2.55

0.25

fi clay 

«0.5u)

_

9.. 4 7

17.21 

17.30

15.39

9.25

4.78

i en 1 . OU

3 .26

_

8

7 -7

. / /

20.97 

24 .51

20.65

14.57

7.56

3.45

0.78

D44 Soil Chronosequences in the Western United States
Supplementary table 3. Extractive chemical analysis

[Analysts: M. C. Rebels and D. M. Cheney, U. S. Geological Survey. , not measured]

Methods

Organic carbon content of most soils was measured by using the Walkley-Black 

titration procedure (Allison, 1965). Organic carbon by percent loss on ignition was 

measured on some soils that were analyzed by D. Cheney. CaCO-j was measured with the 

Chittick apparatus (Bachman and Machette, 1977); 0 value indicates that CaCO-j was not 

measured because no pedogenic CaCO^ was present. Total CaCO-j refers to the CaCO-j 

content of the horizon including gravel and finer sediment.

Acid-soluble (Pa) and organic-bound (Po) phosphorus were measured in selected soil 

profiles with a spectrophotometer (Alexander and Robertson, 1970). Pa was extracted by 

shaking the samples in l^SO^ for 16 hours. Po was obtained by fusing samples with 

calcium acetate, burning off the organic matter, and shaking the samples in l^SO^ for 

16 hours. To obtain an estimate of Po, the amount of Pa measured in the first 

extraction is subtracted from that measured in the second extraction (Williams and 

others, 1967).

No.

1

2

Age

(ka)

modern

modern

Sample

number

RC-R

RC-M

Basal

depth

Horizon (cm)

channel

channel

gravel

gravel

Percent

organic

carbon 1:

0.16

0.96

PH

6.8

8.0

P

I organic

0

0

(ppm)

inorganic

277

269

Percent

<2 mm

0

0

CaCO,

total

0

0

Mountain-front chronosequence

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

7

7

7

7

7

7

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

RC-38

RC-38

RC-38

RC-38

RC-38

RC-38

RC-21

RC-21

RC-21

RC-21

RC-21

RC-21

RC-15

RC-15

RC-15

RC-15

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-17

RC-17

RC-17

RC-17

RC-17

RC-17

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

Al

2A31

2A32

2AC

3Clox

3C2ox

A

Bit

B2t

2B3t

3Clox

3C2ox

A

2B2t

2B3

2Cox

Al

A3

Bit

B21t

B22t

2B31t

2B32t

2Cox

A

Bit

B2t

83 It

2B32t

2Cox

Al

A3

Bit

B2t

2B31t

2B32t

2Cox

9

22

33

46

85

+ 120

5

12

25

38

73

+ 110

823'

43

+68

8

19

32

54

81

123

145

+200

9

20

31

50

122

+ 136

9

17

29

53

81

170

+250

2.87

1.30

1.16

0.45

0.15

0.26

2.53

2.45

2.04

0.57

0.17

0.15

}8.94

3.57 j. ji

Jl.68

0.67

3.96

2.50

1.97

1.82

1.27

0.15

0.05

0.02

\5.52

,4.05

J3.17

2.60

1.42

^.96

4.98

2.71

1.93

1.42

1.17

0.10

0.04

6.3

6.1

6.0

6.0

6.3

5.9

6.1

6.3

6.3

6.4

6.6

6.8

6.0

5.9

5.8

6.0

6.5

6.0

6.1

6.2

6.3

6.6

6.8

6.8

6.4

6.1

5.8

5.4

5.7

5.1

6.2

6.1

6.1

6.2

6.4

6.7

6.7

193

245

178

164

37

0

351

245

170

62

63

13

__

310

364

167

117

142

39

175

0

__

_

_

_

_

303

283

192

153

100

0

38

312

242

184

220

178

121

230

198

148

127

202

194

__

153

103

136

127

100

77

130

158

__

_

_

_

__

168

114

117

89

84

279

270

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D45
Supplementary table 3. Extractive chemical analysis Continued

No.

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

Age

(ka)

600

600

600

600

600

600

600

600

600

600

600

600

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample

number

RC-29

RC-29

RC-29

RC-29

RC-29

RC-29

RC-29

RC-16

RC-16

RC-16

RC-16

RC-16

RC-28

RC-28

RC-28

RC-28

RC-28

RC-28

RC-14

RC-14

RC-14

RC-14

RC-14

RC-14

Horizon

Al

A3

Bit

B2t

2B31t

3B32t

3Cox

A

Bit

2B2t

2B3t

2Cox

A

Bit

B2t

2B31t

2B32t

2Cox

A

Bit

B2t

2B31t

3B32t

3Cox

Basal

depth

(cm)

9

18

30

50

79

167

+260

27

47

72

127

+197

7

11

17

47

141

+270

17

32

44

84

144

+ 164

Percent

organic

carbon

2.90

1.93

1.81

1.66

1.52

0.00

0.00

1 3>3A

h.ll

J2.44

J3.30

0.98

3.12

1.82

2.16

0.56

0.19

0.08

J5.35

3.78

J3.07

J2.22

1.43 i .<+j

0.85

PH

1:1 H20

6.2

5.9

5.9

6.0

5.9

6.7

6.9

5.4

5.6

5.6

5.9

5.7

6.0

6.0

6.0

6.0

6.6

7.1

5.3

5.6

5.6

5.6

6.2

6.3

P

organic

287

223

268

120

123

86

0

__

_

~

362

267

1130

132

146

0

(ppm)

inorganic

208

133

166

175

166

236

437

_

--

178

130

115

89

129

132

Percent

<2 mm

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

CaCOtotal

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Transition chronosequence

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

7

7

7

7

7

7

7

7

7

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

120

RC-40

RC-40

RC-40

RC-40

RC-42

RC-42

RC-42

RC-42

RC-42

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-12

RC-12

RC-12

RC-12

RC-12

RC-32

RC-32

RC-32

RC-32

RC-41

RC-41

RC-41

RC-41

RC-41

RC-41

A

Bs

2Clox

2C2ox

Al

A3

2Bs

3Bb

3Coxb

A

Bit

B2t

2B3t

2Clox

2C2ox

3Cca

3Cn

A

Bit

B2t

2B3t

2Cox

Ap

2B2tca

2B3tca

3Cca

A

Bit

B2t

2B31t

2B32t

2Cox

13

46

65

310

6

37

55

73

+200

5

25

43

57

78

175

197

+240

9

17

39

62

+ 122

21

37

70

+80

8

17

28

51

65

+ 100

1 5 . 12

J4.23

Jl.38

1 0.70

3.80

2.34

1.15

0.94

0.22

3.54

1.83

1.37

0.73

0.31

0.14

0.55

0.04

js.oo

J3.85

2.78 0 7fl

M.90

1.06

2.32

1.54

1.95

0.07

5.28

2.17

2.02

1.87

0.28

0.06

7.1

6.6

6.8

7.0

7.1

6.1

6.7

6.8

7.0

6.9

6.6

6.8

6.9

7.1

6.9

7.9

7.7

6.2

6.4

6.4

6.8

7.0

7.2

7.5

8.0

8.1

6.7

6.6

6.5

6.7

7.1

7.3

_

_

_

__

__

_

_

528

266

257

131

20

48

_

__

__

--

__

_

_

~

289

169

137

205

243

188

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3.01

0

0

0

0

0

0

0

0.58

3.92

0.38

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

D46 Soil Chronosequences in the Western United States
Supplementary table 3. Extractive chemical analysis Continued

No.

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

Age 

(ka)

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Basal Percent 

Sample depth organic pH P

number Horizon (cm) carbon

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-8

RC-8

RC-8

RC-8

RC-8

A

B2t

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

A

Bit

B2tca

B3tca

K

2Clca

3C2ca

3C3ca

3C4ca

4C5ca

4C6ca

Al

A3

Bit

B2t

2B3t/ca

2K1

2K2

3Clca

3C2ca

A

B2t

2B3tca

2K

2Cca

9

20

50

100

+180

6

18

45

63

109

230

+240

8

14

22

37

54

89

160

+210

5

10

18

32

54

135

225

+235

13

30

46

96

+ 126

7

16

25

35

53

80

103

173

200

227

+255

9

16

24

43

58

58

92

180

+220

8

22

72

112

+ 162

J3.98

J3.96

}2.18

1.51

1 0.56

3.00

1.83

1.92

2.22

1.20

0.01

2.05

2.47

1.78

1.56

1.06

0.26

0.08

0.01

J4.41

5.35

|6.84

5.74

|2.73

J2. 71

jl.08

1 1.02

1 5 . 58

Jaiao

i 3.43 J * HJ

|2.42

0.83

0.23

2.47

1.93

1.26

1.16

0.66

1.46

2.07

1.18

0.08

0.10

1.90

2.24

2.23

1.76

2.00

1.49

0.32

0.04

0.00

J6.30

5.41 J . +!

J4.98

J2.16

1.66

(ppm) Percent CaC00

1:1 HjO organic Inorganic <2 mm total^

5.6

5.7

6.4

7.5

7.7

7.0

7.1

7.3

7.7

7.8

8.1

5.7

5.4

5.5

5.5

6.9

6.7

7.9

7.8

6.9

6.5

7.0

7.5

7.6

7.9

8.0

8.0

6.6

6.6

6.8

7.5

8.0

7.3

7.1

7.5

7.9

8.0

8.3

8.3

8.4

8.5

8.6

8.4

6.4

6.6

6.6

6.9

7.6

7.9

7.9

8.2

8.2

7.2

7.0

7.5

7.8

7.8

0

0

0

9.65

1.31

0

0

0.2

43.8

29.1

1.29

0

0

0

0

0.22

7.34

3.36

0.73

0

0

3.4

34.6

32.9

25.0

7.3

4.8

0

0

0.3

31.5

7.5

0

0

0.55

34.5

53.2

32.0

20.2

20.2

7.47

2.92

0.13

0

0

0

0

4.63

19.6

17.1

2.45

0.87

0

0

28.5

22.3

16.7

0

0

0

0

0

17.7

4.1

0

0

0

0

5.8

1.35

0

0

_

33.7

10.6

2.6

0

0

0

0

49.1

15.6

3.5

0

0

0

0

11.3

10.0

1.2

0.5

0

0

_

~

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D47
Supplementary table 3. Extractive chemical analysis Continued

No.

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

Age 

(ka)

7

7

7

7

7

7

7

7

20

20

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

Sample 

number

RC-46A

RC-46A

RC-46A

RC-46A

RC-46A

RC-46B

RC-46B

RC-46B

RC-20

RC-20

RC-20

RC-20

RC-20

RC-20

RC-43

RC-43

RC-43

RC-43

RC-43

RC-43

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

Horizon

Ap

ACca

2Cgca

2Cox

3Cn

Apca

2Cca

3Cn

A

2Blt

2B2tca

2B3tca

3Clca

3C2ca

A

Bit

B2t

2B3tca

2Clca

3C2ca

A

2Blt

2B2t

3B3ca

3Clca

4C2ca

5C3ca

A

Bltca

B2tca

B3tca

2K

3Clca

3C2ca

4C3ca

5C4ca

5C5ca

5C6ca

A

Bit

B2tca

B3tca

K

2Clca

2C2ca

2C3ca

Aca

Bltca

B2tca

B3tca

2K

2Clca

2C2ca

3C3ca

Aca

Bltca

B21tca

B22tca

B31tca

2B32tca

2Cca

Basal Percent 

depth organic 

(cm) carbon

Basin

20

40

70

98

+ 150

28

60

+ 150

9

15

32

50

130

+330

18

33

44

65

98

+200

6

11

19

34

74

147

+225

3

7

14

29

60

121

170

226

255

310

+320

4

9

19

30

45

62

87

+300

4

9

15

25

49

65

91

+ 130

6

13

19

27

45

86

+ 120

PH 

1:1 H2 0

P (ppm)

organic inorg

Percent CaCOa

;anic <2 mm total"

chronosequence

1.78

0.37

1.06

0.20

0.12

1.84

0.40

0.12

1.90

1.35

0.72

0.48

0.07

0.02

2.58

2.07

2.22

0.90

0.23

0.05

1 6 75

}7.'69

7.13 ; . i j

[5.38

JJ.7-+ 3.94

^.20

3.93

2.39

2.83

1.85

0.47

0.19

0.11

0.04

0.05

0.10

2.27

2.36

1.60

1.34

2.00

0.32

0.15

0.0

J7.47

,8.42

7 i .23ij

6.52

75.02

3.55 j. jj

J2.10

3.30

2.49

2.67

2.72

2.43

1.91

0.45

0.21

8.0

8.1

8.1

7.8

7.8

7.9

8.0

7.8

7.0

7.4

7.7

8.3

8.6

8.9

7.3

7.7

7.8

8.1

8.2

8.4

7.9

7.5

7.5

7.8

7.8

8.6

7.9

6.7

7.2

7.4

7.5

7.8

7.8

7.8

8.0

8.0

8.0

6.4

6.7

7.4

8.0

8.0

8.3

8.5

8.7

7.4

7.3

7.4

7.4

7.6

7.9

8.1

8.4

7.5

7.5

7.8

7.9

7.9

8.3

8.6

_

0

250

289

127

25

7

_

__

_

235

165

258

416

143

81

0

286

187

291

350

96

122

13

_

211

273

295

281

270

76

32

_

756

296

287

224

364

278

_

549

465

405

311

146

150

185

--

--

449

378

446

383

395

203

232

_

452

384

450

389

401

205

235

1.49

5.58

3.06

0.39

0.04

2.88

2.71

0.04

. 0

0

0.35

0.43

0.99

0.28

0

0

0

7.92

2.15

1.10

7.66

1.17

0.54

20.5

14.0

10.9

6.50

0

0.79

9.85

26.6

30.6

6.39

2.68

7.66

1.70

7.30

0

0

1.53

25.6

51.4

16.4

2.25

2.32

4.03

18.4

27.3

36.0

50.4

30.4

11.0

11.2

3.31

5.88

16.1

28.7

44.5

11.9

2.84

1.49

5.58

3.06

0.39

0

0

1.2

0.4

3.3

0

0

0

_

__

0

0.8

12.2

21.5

19.4

4.7

1.3

4.5

1.3

0

0

4.3

0.5

_

24.2

23.0

28.2

15.5

__

D48 Soil Chronosequences in the Western United States
Supplementary table 3. Extractive chemical analysis Continued

No.

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

Age 

(ka)

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample 

number

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

Horizon

A

Bit

B21t

B22tca

B3tca

2K

2Clca

2C2ca

3C3ca

A

Bit

B2tca

B31tca

B32tca

2K

2Clca

2C2ca

Basal 

depth 

(cm)

6

11

20

29

40

68

145

247

295

5

10

16

25

36

48

88

+ 170

Percent 

organic 

carbon

1.82

2.30

2.12

2.29

2.08

1.78

0.17

0.02

0.02

Js.86

6.34

J6.30

J7.69

,6.66

16.12

J3.34

1.58

pH 

1:1 H2 0

6.6

6.9

7.0

7.4

7.9

7.9

8.9

8.9

8.6

6.8

6.8

7.1

7.4

7.5

7.6

7.9

8.2

P (ppm)

organic

153

164

207

161

329

300

78

0

66

_

_

_

_

inorganic

385

322

331

341

320

234

318

229

156

_

_

_

_-

Percent CaCO^

<2 mm

0

0

0

1.05

30.8

50.7

15.4

2.99

0.37

0

0

0.82

20.2

37.0

41.7

29.5

9.22

total

0

0

0

28.5

4.1

0.7

0

0

25.5

Measured by loss on ignition.

Supplementary table 4. Clay mineralogy

[Analyst: M. C. Rebels, U. S. Geological Survey. , not measured]

Methods

Samples of clay fractions drawn from settling tubes after particle-size analyses 

were plated on ceramic tiles (Whlttig, 1965). X-ray-diffraction traces (CuK alpha 

radiation) were run on these oriented clays after the following treatments: airdried, glycolated, and heated to 400 and 550 °C. Clay mineral percentage for Rock 

Creek soils was calculated by using the formulas based on peak heights and areas 

developed by Schultz (1964) in work on the mineralogy of the Plerre Shale (Upper 

Cretaceous). In his study, these formulas gave an accuracy of determination of ±10 

percent when clay constituted more than 15 percent of the sample (the rest was 

amorphous material and/ or nonclay minerals).

percent of clay mineral

No. Age

(ka)

1 modern

2 modern

Sample

number

RC-R

RC-M

Basal

Horizon depth

channel gravel

channel gravel

Kaolir- Chlonite rite

45 9

Vermiculite

0

Mixed-layer

Mica smectite-illite

8 24

Smectite

14

Mountain-front chronosequence

3

4

5

6

7

8

7 RC-38

7 RC-38

7 RC-38

7 RC-38

7 RC-38

7 RC-38

Al

2A31

2A32

2AC

3Clox

3C2ox

9

22

33

46

85

+ 120

27

20

19

10

6

11

10

2

3

2

0

0

0

0

0

42

42

18

18

21

12

19

51

61

66

7

9

9

9

5

9

10

11

12

13

14

20

20

20

20

20

20

RC-21 

RC-21 

RC-21 

RC-21 

RC-21 

RC-21

A

Bit

B2t

2B3t

3Clox

3C2ox

5 

12 

25 

38 

73 

+ 110

13 3

27 4

25 2

23 2

8 2

0

0

0

15

0

17

31

25

12

14

61

26

33

20

72

6

12

15

28

4

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D49
Supplementary table 4. Clay mineralogy Continued

percent of clay mineral

No.

15 

16 

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

Age 

(ka)

20 

20 

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

7

7

7

7

7

7

7

7

7

Sample 

number

RC-15 

RC-15 

RC-15

RC-15

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-17

RC-17

RC-17

RC-17

RC-17

RC-17

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

RC-29

RC-29

RC-29

RC-29

RC-29

RC-29

RC-29

RC-16

RC-16

RC-16

RC-16

RC-16

RC-28

RC-28

RC-28

RC-28

RC-28

RC-28

RC-14

RC-14

RC-14

RC-14

RC-14

RC-14

RC-40

RC-40

RC-40

RC-40

RC-42

RC-42

RC-42

RC-42

RC-42

Basal Kaoli-ChloHorizon depth nite rite

A 

2B2t 

2B3

2Cox

Al

A3

Bit

B21t

B22t

2B31t

2B32t

2Cox

A

Bit

B2t

B31t

2B32t

2Cox

Al

A3

Bit

B2t

2B31t

2B32t

2Cox

Al

A3

Bit

B2t

2B31t

3B32t

3Cox

A

Bit

2B2t

2B3t

2Cox

A

Bit

B2t

2B31t

2B32t

2Cox

A

Bit

B2t

2B31t

3B32t

3Cox

A

Bs

2Clox

2C2ox

Al

A3

2Bs

3Bb

3Coxb

8 

23 

43

+68

8

19

32

54

81

123

145

+200

9

20

31

50

122

+ 136

9

17

29

53

81

170

+250

9

18

30

50

79

167

+260

27

47

72

127

+ 197

7

11

17

47

141

+270

17

32

44

84

144

+ 164

Transition

13

46

65

310

6

37

55

73

+200

26

22

27

22

11

8

3

1

_

8

17

15

2

4

4

1

22

15

26

23

13

3

3

13

15

24

10

1

4

6

4

3

9

4

6

2

5

_

10

9

2

2

2

2

2

3

3

2

6

3

2

1

0

0

0

0

0

0

Vermiculite

0

0

0

7

8

12

15

24

_

~

0

0

3

4

10

5

2

0

0

5

10

6

8

8

0

0

0

9

21

17

Mixed-layer SmecMica smectite-illite tite

39

44

19

21

22

17

10

24

_

72

75

52

15

10

23

11

40

54

40

38

50

19

20

47

26

15

44

5

15

25

23

35

16

46

51

59

36

_

2

0

21

65

64

56

73

23

18

16

6

16

51

50

41

54

53

26

53

53

4

8

15

26

9

7

11

10

_

8

5

7

12

11

10

10

12

10

11

17

12

17

17

0

5

8

12

20

11

chronosequence

31

28

37

39

42

__

7

6

5

5

0

_

0

0

0

0

0

_

31

36

42

38

29

_

20

19

0

0

3

_

11

11

17

18

26

D50 Soil Chronosequences in the Western United States
Supplementary table 4. Clay mineralogy Continued

percent of clay mineral

No.

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

Age 

(ka)

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

Sample 

number

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-12

RC-12

RC-12

RC-12

RC-12

RC-32

RC-32

RC-32

RC-32

RC-41

RC-41

RC-41

RC-41

RC-41

RC-41

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

Horizon

A

Bit

B2t

2B3t

2Clox

2C2ox

3Cca

3Cn

A

Bit

B2t

2B3t

2Cox

Ap

2B2tca

2B3tca

3Cca

A

Bit

B2t

2B31t

2B32t

2Cox

A

82 1

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

Basal Kaoli-Chlo- Vermidepth nlte rite culite

5

25

43

57

78

175

197

+240

9

17

39

62

+ 122

21

37

70

+80

8

17

28

51

65

+ 100

9

20

50

100

+180

6

18

45

63

109

230

+240

8

14

22

37

54

89

160

+210

5

10

18

32

54

135

225

+235

13

30

46

96

+126

27

20

18

13

15

20

14

23

32

32

56

49

40

38

37

24

21

23

27

24

19

28

21

26

15

14

11

19

29

5

6

0

6

7

0

4

3

5

4

0

2

1

2

4

2

4

3

3

3

6

5

0

6

7

2

5

6

7

--

0

0

0

0

0

0

0

0

0

4

0

0

0

0

0

0

0

0

5

4

0

0

0

0

0

5

0

14

0

Mixed-layer SmecMica smectite-illite tite

45

37

25

47

31

24

12

20

22

18

33

19

11

8

13

9

38

16

16

13

17

23

 

30

32

31

46

23

22

18

15

31

52

15

27

37

50

37

19

30

3

21

39

43

34

56

33

47

26

26

27

11

"

40

24

40

19

39

19

17

 _

7

6

6

19

20

19

 

 

20

16

22

11

8

9

9

10

13

9

5

11

23

31

31

33

8

12

7

14

22

19

30

"

--

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D51
Supplementary table 4. Clay mineralogy Continued

percent of clay mineral

No. Age

(ka)

129

130

131

132

133

134

135

136

137

138

139

1AO

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

7

7

7

7

7

7

7

7

20

20

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

Sample

number

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-8

RC-8

RC-8

RC-8

RC-8

RC-46A

RC-46A

RC-46A

RC-46A

RC-46A

RC-46B

RC-46B

RC-46B

RC-20

RC-20

RC-20

RC-20

RC-20

RC-20

RC-43

RC-43

RC-43

RC-43

RC-43

RC-43

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

Basal Kaoli-Chlo- VermlHorlzon

A

Bit

B2tca

B3tca

K

2Clca

3C2ca

3C3ca

3C4ca

4C5ca

4C6ca

Al

A3

Bit

B2t

2B3t/ca

2K1

2K2

3Clca

3C2ca

A

B2t

2B3tca

2K

2Cca

Ap

ACca

2Cgca

2Cox

3Cn

Apca

2Cca

3Cn

A

2Blt

2B2tca

2B3tca

3Clca

3C2ca

A

Bit

B2t

2B3tca

2Clca

3C2ca

A

2Blt

2B2t

2B3ca

3Clca

4C2ca

5C3ca

A

Bltca

B2tca

B3tca

2K

3Clca

3C2ca

4C3ca

5C4ca

5C5ca

5C6ca

depth

7

16

25

35

53

80

103

173

200

227

+255

9

16

24

43

58

58

92

180

+220

8

22

72

112

+ 162

Basin

20

40

70

98

+150

28

60

+ 150

9

15

32

50

130

+330

18

33

44

65

98

+200

6

11

19

34

74

147

+225

3

7

14

29

60

121

170

226

255

310

+320

nite

46

26

20

37

34

35

31

34

31

27

28

13

25

13

10

7

6

rite culite

5

1

7

6

6

4

5

6

3

8

5

2

2

0

0

0

0

0

0

8

13

18

5

17

0

0

0

0

0

0

0

0

0

0

Mixed-layer SmecMica smectite-illite tite

33

26

18

20

15

20

20

20

24

24

31

15

22

13

11

4

7

2

39

17

10

2

15

0

0

0

32

18

59

33

63

43

65

66

15

9

30

14

24

22

37

40

42

8

18

10

19

11

36

23

21

chronosequence

_

33

21

33

35

32

_

21

19

22

33

27

21

21

_

0

0

0

1

0

_

0

2

1

2

1

0

0

__

0

0

0

0

0

0

0

0

0

0

0

0

_

 

31

13

16

19

18

14

23

22

7

6

8

6

_

23

52

23

15

12

55

42

33

38

25

29

24

_

13

14

28

29

38

10

13

22

20

41

43

48

D52 Soil Chronosequences in the Western United States
Supplementary table 4. Clay mineralogy Continued

percent of clay mineral

No.

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

Age 

(ka)

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000.

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample 

number

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

Horizon

A

Bit

B2tca

B3tca

K

2Clca

2C2ca

2C3ca

Ac a

Bltca

B2tca

B3tca

2K

2Clca

2C2ca

3C3ca

Aca

Bltca

B21tca

B22tca

B31tca

2B32tca

2Cca

A

Bit

B21t

B22tca

B3tca

2K

2Clca

2C2ca

3C3ca

A

Bit

B2tca

B31tca

B32tca

2K

2Clca

2C2ca

Basal 

depth

4

9

19

30

45

62

87

+300

4

9

15

25

49

65

91

+ 130

6

13

19

27

45

86

+ 120

6

11

20

29

40

68

145

247

295

5

10

16

25

36

48

88

+170

Kaoll-Chlonlte rite

12

20

19

32

23

18

_

35

19

25

7

35

12

3

18

24

16

12

2

2

__

2

2

1

2

2

1

_

9

5

3

4

5

2

2

9

2

2

8

1

0

Vermicullte

0

0

0

0

0

0

_

0

0

0

0

0

0

0

0

0

0

0

0

0

Mixed-layer SmecMLca smectlte-llllte tlte

20

19

30

19

12

4

_

33

10

21

15

16

4

3

37

10

15

32

4

2

54

45

36

25

30

32

_

9

59

36

44

12

32

39

26

52

42

11

45

46

13

13

14

22

32

44

_

14

8

14

30

32

51

53

11

12

25

37

49

50

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D53
Supplementary table 5. Total chemical analysis of fine fraction by induction-coupled 

plasma spectroscopy

[Analysts: C. Gent and D. Fey under supervision of J. L. Seeley and L. R. Layman, U.S. Geological 

Survey. , not measured]

Methods

The less-than-2 mm and the silt-plus-clay fractions of selected soil samples and the dust-trap 

sample were analyzed for major elements and Zr by the Analytical Laboratories of the U. S. 

Geological Survey. To avoid chemical contamination in obtaining the silt-plus-clay fraction, soils 

were dispersed by shaking samples overnight in distilled water and then sonicating them in a water 

bath. Sand was removed by wet-sieving, and the silt-plus-clay fraction was dried and ground.

Oxides were determined by inductively coupled argon plasma emission spectroscopy (ICP). This 

method is noted for its high sensitivity to most elements once they are in solution (Taggart and 

others, 1981) (ICP accuracy is estimated at 3-5 percent and precision at 1-2 percent; J. E. Taggart, 

oral commun., 1982). X-ray fluorescence (XRF) is a more accurate method, but it is not sensitive to 

small amounts of such elements as Zr (there is less than 0.1 percent in the silt-plus-clay fractions 

of soils in the study area). Because determination of Zr was critical to this study, all samples 

were run using ICP, with revised pretreatments that dissolved Zr. Selected samples were split and 

analyzed by using both ICP and XRF as a check on the accuracy of ICP, and the separate analyses 

agreed closely (data not shown).

No.

1

2

Age

(ka)

modern

modern

Sample

number Horizon

RC-R

RC-M

channel

channel

Basal

depth

(cm)

gravel

gravel

Percent of silt-plus-clay

Si02

51

67

A12°3

14.37

12.16

Mountain-front

3

4

5

6

7

8

9

10

11

12

13

14 

15

16 

17

1 Qlo

19

20

21

22

23

24

25

26

27 

28 

29

30

31

32 

33

34

35

36

37

38

39

7

7

7

7

7

7

20

20

20

20

20

20 

20

20 

20

20

120

120

120

120

120

120

120

120

120 

120 

120

120

120

120 

415

415

415

415

415

415

415

RC-38

RC-38

RC-38

RC-38

RC-38

RC-38

RC-21

RC-21

RC-21

RC-21

RC-21

RC-21 

up 1 ; IX V^ 1 J

RC-15

PP 1 ^ Ko 1 J 

PP 1 ^ IxO 1 J

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

UP 1 7

KV^ 1 /

RC-17 

RC-17

PP 1 7

KL. 1 / 

PP 1 7

Ko 1 / 

P P 1 7

Ko 1 /

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

RC-30

Al

2A31

2A32

2AC

3Clox

3C2ox

A

Bit

B2t

2B3t

3Clox

3C2ox

2B2t

2Cox

Al

A3

Bit

B21t

B22t

2B31t

2B32t

2Cox

Bit 

B2t

1>O 1 *.

D J 1 C

2Cox 

Al

A3

Bit

B2t

2B31t

2B32t

2Cox

9

22

33

46

85

+ 120

5

12

25

38

73

+ 110

23

43

1 £ Q

+ DO

8

19

32

54

81

123

145

+200

9 

20 

31

50

122

J_ 1 O £.

Tj. JO

9

17

29

53

81

170

+250

56

58

60

62

64

67

60

62

62

62

58

64

62

59

58

60

62

52

52

51

53

64

56

53

56

48

49

47

49

12.57

13.55

14.05

14.74

15.43

16.45

13.21

14.33

14.78

15.52

16.31

16.86

13.14

13.48

14.23

14.61

14.90

19.85

20.04

19.09

18.41

15.44

13.52

14.59

15.50

18.56

18.49

19.66

19.85

Fe 20 3

7.10

3.96

MgO

2.90

1.63

CaO

3.48

2.56

Na20

2.57

1.35

fraction

K20 Ti02

2.01 0.73

2.17 0.57

MnO Zr02

0.092 0.064

0.061 0.082

chronosequence

3.79

4.03

4.06

3.94

3.73

4.43

4.52

4.85

4.98

5.15

6.41

5.48

4.23

4.65

4.94

4.76

4.97

6.63

6.94

8.47

7.94

4.85

4.99

5.59

5.84

8.08

7.74

9.14

9.28

1.39

1.43

1.44

1.48

1.54

1.77

1.21

1.21

1.30

1.43

1.74

1.66

1.51

1.29

1.31

1.28

1.45

1.66

1.92

2.69

2.72

1.46

1.49

1.59

1.71

2.55

2.64

2.82

2.99

2.11

1.97

2.04

2.27

2.03

2.08

1.47

1.08

1.00

1.16

1.93

2.39

1.86

1.65

1.44

1.17

1.25

1.54

2.14

2.56

2.60

0.99

1.90

1.65

1.61

1.99

1.75

1.79

1.59

2.79

2.99

3.22

3.69

4.22

4.16

1.59

1.52

1.37

1.36

2.60

3.68

2.10

1.59

1.60

1.64

1.66

1.63

2.48

2.35

2.63

1.25

1.64

1.58

1.62

1.61

1.44

1.29

1.19

2.22 0.47

2.29 0.48

2.28 0.50

2.33 0.48

2.45 0.47

2.53 0.57

2.28 0.60

2.35 0.63

2.28 0.63

2.10 0.58

2.18 0.65

2.41 0.57

2.20 0.57

2.41 0.58

2.34 0.57

2.25 0.55

2.18 0.57

1.75 0.60

1.78 0.68

1.54 0.78

1.82 0.83

2.27 0.63

2.41 0.60

2.28 0.60

2.30 0.62

1.84 0.71

1.71 0.60

1.65 0.65

2.00 0.63

0.084 0.043

0.085 0.046

0.078 0.047

0.056 0.050

0.039 0.046

0.038 0.053

0.079 0.045

0.073 0.047

0.053 0.043

0.039 0.043

0.059 0.076

0.052 0.079

0.085 0.050

0.093 0.045

0.065 0.042

0.040 0.041

0.036 0.046

0.036 0.036

0.054 0.039

0.071 0.032

0.075 0.046

0.041 0.051

0.090 0.041

0.074 0.036

0.062 0.038

0.053 0.028

0.054 0.026

0.076 0.030

0.065 0.026

D54 Soil Chronosequences in the Western United States
Supplementary table 5. Total chemical analysis of fine fraction by induction-coupled 

plasma spectroscopy Continued

No.

40 

41 

42 

43 

44 

45 

46

47 

48 

49 

50 

51

52 

53 

54 

55 

56 

57

58 

59 

60 

61 

62 

63

Age 

(ka)

600 

600 

600 

600 

600 

600 

600

600 

600 

600 

600 

600

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Basal Percent of silt-plus-clay fraction

Sample depth 

number Horizon (cm) Si02 Al^O, Fe.O,

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 '

RC-16 

RC-16 

RC-16 

RC-16 

RC-16

RC-28 

RC-28 

RC-28 

RC-28 

RC-28 

RC-28

RC-14 

RC-14 

RC-14 

RC-14 

RC-14 

RC-14

Al 

A3 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bit 

2B2t 

2B3t 

2Cox

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

2B31t 

2B32t 

3Cox

9 

18 

30 

50 

79 

167 

+260

27 

47 

72 

127 

+197

7 

11 

17 

47 

141 

+270

17 

32 

44 

84 

144 

+ 164

59 

56 

58 

55 

56 

53 

51

53

53

60 

60 

59 

53 

49 

53

14.46 

14.93 

14.86 

15.73 

15.80 

16.39 

18.05

18.13

17.16

13.33 

14.90 

16.27 

17.96 

18.70 

18.41

5.49 

5.68 

5.52 

6.31 

6.68 

8.50 

S.71

7.42

5.71

4.41 

4.78 

5.42 

6.31 

7.80 

6.88

, MgO

1.72 

1.64 

1.61 

2.36 

2.06 

3.23 

3.22

2.77

1.67

1.09 

1.21 

1.49 

1.86 

2.59 

2.04

CaO Na20

1.75 1.81 

1.71 1.79 

1.65 1.85 

1.62 1.72 

1.85 1.87 

2.57 2.32 

1.87 1.44

1.94 1.60

1.51 1.90

1.31 1.43 

1.06 1.31 

1.18 1.25 

1.71 2.10 

1.93 1.82 

1.94 2.37

K 0 TiO

2.53 0.65 

2.46 0.67 

2.29 0.68 

2.11 0.66 

2.24 0.72 

2.02 0.85 

1.99 0.65

1.75 0.65

2.43 0.58

2.37 0.63 

2.31 0.65 

2.06 0.64 

1.84 0.65 

1.69 0.62 

2.43 0.65

2 MnO

0.074 

0.085 

0.070 

0.063 

0.085 

0.087 

0.063

0.053

0.061

0.075 

0.050 

0.045 

0.056 

0.076 

0.078

ZrO,

0.040 

0.036 

0.038 

0.032 

0.040 

0.036 

0.026

0.039

0.036

0.035 

0.039 

0.032 

0.030 

0.022 

0.038

Transition chronosequence

64 

65 

66 

67

68 

69 

70 

71 

72

73 

74 

75 

76 

77 

78 

79 

80

81 

82 

83 

84 

85

86 

87 

88 

89

90 

91 

92 

93 

94 

95

7 

7 

7 

7

7 

7 

7 

7 

7

20 

20 

20 

20 

20 

20 

20 

20

120 

120 

120 

120 

120

120 

120 

120 

120

120 

120 

120 

120 

120 

120

RC-40 

RC-40 

RC-40 

RC-40

RC-42 

RC-42 

RC-42 

RC-42 

RC-42

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22

RC-12 

RC-12 

RC-12 

RC-12 

RC-12

RC-32 

RC-32 

RC-32 

RC-32

RC-41 

RC-41 

RC-41 

RC-41 

RC-41 

RC-41

A 

Bs 

2Clox 

2C2ox

Al 

A3 

2Bs 

3Bb 

3Coxb

A 

Bit 

B2t 

2B3t 

2Clox 

2C2ox 

3Cca 

3Cn

A 

Bit 

B2t 

2B3t 

2Cox

Ap 

2B2tca 

2B3tca 

3Cca

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

13 

46 

65 

310

6 

37 

55 

73 

+200

5 

25 

43 

57 

78 

175 

 197 

+240

9 

17 

39 

62

+ 122

21 

37 

70 

+80

8 

17 

28 

51 

65 

+ 100

64 

64 

64 

64 

60

58

66 

66 

58 

51 

56 

51

10.89 

11.87 

13.16 

13.17 

15.16

16.07

10.70 

12.31 

15.82 

19.28 

18.09 

19.85

3.51 

3.95 

4.35 

4.56 

5.74

5.26

3.40 

3.91 

5.24 

6.87 

6.22 

7.01

1.13 

1.23 

1.38 

1.44 

1.74

1.91

0.91 

0.95 

1.31 

1.86 

1.94 

2.17

1.34 1.58 

1.37 1.50 

1.30 1.47 

1.37 1.62 

1.61 1.63

1.58 0.69

1.09 1.25 

0.92 1.15 

0.88 0.73 

1.09 0.67 

1.24 0.78 

1.24 0.66

2.46 0.50 

2.37 0.53 

2.30 0.57 

2.34 0.57 

2.34 0.57

2.31 0.58

2.19 0.55 

2.35 0.62 

2.33 0.58 

2.46 0.58 

2.24 0.57 

2.31 0.58

0.057 

0.061 

0.047 

0.057 

0.062

0.047

0.056 

0.049 

0.043 

0.050 

0.045 

0.052

0.053 

0.050 

0.051 

0.052 

0.053

0.035

0.055 

0.049 

0.041 

0.031 

0.039 

0.031

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D55
Supplementary table 5. Total chemical analysis of fine fraction by induction-coupled 

plasma spectroscopy Continued

No.

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

Age

(ka)

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample

dumber

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-8

RC-8

RC-8

RC-8

RC-8

Horizon

A

B2t

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

A

Bit

B2tca

B3tca

K

2Clca

3C2ca

3C3ca

3C4ca

4C5ca

4C6ca

Al

A3

Bit

B2t

2B3t/ca

2K1

2K2

3Clca

3C2ca

A

B2t

2B3tca

2K

2Cca

Basal Percent of silt-plus-clay fraction

depth

(cm) Si02 A120 3 Fe 2 03 MgO CaO Na2 0 K20 Ti02 MnO Zr02

20 56 16.39 5.94 1.86 1.41 0.98 2.13 0.60 0.111 0.042

50 100 

+ 180 

6

18 

45 

63 

109

230

+240

8 __ __

14

22

37 __ __

54 

89 

160

+210 

5 __ __

10 

18

32 

54 ~

225

+235 

13 

30 

46 

96 __ __

+ 126

7

16

25

35 __ __

53 __ __ __ __ __ __ __ __ __ _

80

!03 -- --

173 

200 

227 -- 

+255 

9

16

24 

43 

58

58 __ __

92 

180

+220

8

22 

72

112 

+ 162

D56 Soil Chronosequences in the Western United States
Supplementary table 5. Total chemical analysis of fine fraction by induction-coupled 

plasma spectroscopy Continued

No. Age 

(ka)

Sample 

number Horizon

Basal

depth 

(cm)

Percent of silt-plus-clay

Si02 «2°3 "A MgO CaO »,2 o

fraction

K20 Ti02 MnO Zr02

Basin chronosequence

154 

155 

156 

157 

158

159 

160 

161

162 

163 

164 

165 

166 

167

168 

169 

170 

171 

172 

173

174 

175 

176 

177 

178 

179 

180

181 

182 

183 

184 

185 

186 

187 

188 

189 

190 

191

192 

193 

194 

195 

196 

197 

198 

199

200 

201 

202 

203 

204 

205 

206 

207

208 

209 

210 

211 

212 

213 

214

7 

7 

7 

7 

7

7 

7 

7

20 

20 

20 

20 

20 

20

20 

20 

20 

20 

20 

20

120 

120 

120 

120 

120 

120 

120

415 

415 

415 

415 

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600 

600

945 

945 

945 

945 

945 

945 

945 

945

945 

945 

945 

945 

945 

945 

945

RC-46A 

RC-46A 

RC-46A 

RC-46A 

RC-46A

RC-46B 

RC-46B 

RC-46B

RC-20 

RC-20 

RC-20 

RC-20 

RC-20 

RC-20

RC-43 

RC-43 

RC-43 

RC-43 

RC-43 

RC-43

RC-27 

RC-27 

RC-27 

RC-27 

RC-27 

RC-27 

RC-27

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44

Ap 

ACca 

2Cgca 

2Cox 

3Cn

Apca 

2Cca 

3Cn*

A 

2Blt 

2B2tca 

2B3tca 

3Clca 

3C2ca

A 

Bit 

B2t 

2B3tca 

2Clca 

3C2ca

A 

2Blt 

2B2t 

2B3ca 

3Clca 

4C2ca 

5C3ca

A 

Bltca 

B2tca 

B3tca 

2K 

3Clca 

3C2ca 

4C3ca 

5C4ca 

5C5ca 

5C6ca

A 

Bit 

B2tca 

B3tca 

K 

2Clca 

2C2ca 

2C3ca

Ac a 

Bltca 

B2tca 

B3tca 

2K 

2Clca 

2C2ca 

3C3ca

Aca 

Bltca 

B21tca 

B22tca 

B31tca 

2B32tca 

2Cca

20 

40 

70 

98 

+ 150

28 

60 

+ 150

9 

15 

32 

50 

130 

+330

18 

33 

44 

65 

98 

+200

6 

11 

19 

34 

74 

147 

+225

3 

7 

14 

29 

60 

121 

170 

226 

255 

310 

+320

4 

9 

19 

30 

45 

62 

87 

+300

4 

9 

15 

25 

49 

65 

91 

+ 130

6 

13 

19 

27 

45 

86 

+ 120

66 

68 

71

66 

58 

50 

60 

60 

58

56 

65 

59 

45 

52 

56 

58

64 

64 

56 

43 

26 

53 

64 

55 

64

62 

60 

60 

45 

24 

39 

49 

57

45

60 

56 

49 

41 

30 

45 

56

12.44 

10.57 

10.72

12.72 

15.12 

15.60 

14.74 

14.03 

14.91

11.81 

13.59 

15.65 

10.23 

11.15 

11.83 

13.02

12.12 

12.10 

12.04 

9.02 

5.39 

10.91 

11.46 

10.85 

11.13

13.76 

14.20 

14.59 

9.62 

5.41 

10.21 

11.32 

11.44

9.19

12.87 

13.67 

11.72 

9.15 

7.05 

9.34 

10.53

4.21 

4.21 

5.08

4.36 

5.61 

5.92 

5.22 

5.09 

5.54

4.21 

4.88 

5.59 

3.33 

3.66 

4.02 

4.25

3.99 

4.01 

4.02 

2.90 

1.52 

3.81 

4.42 

3.73 

5.16

4.82 

5.05 

5.29 

3.25 

1.75 

3.48 

4.66 

5.19

3.10

4.28 

4.61 

3.98 

2.98 

2.25 

3.30 

3.92

2.06 

2.34 

2.31

1.24 

1.66 

1.94 

1.79 

1.89 

2.22

2.17 

1.91 

2.09 

2.31 

2.67 

3.88 

3.57

1.28 

1.29 

1.49 

1.28 

1.71 

3.20 

4.59 

5.16 

4.79

1.49 

1.59 

1.86 

2.21 

2.67 

4.58 

6.33 

5.39

1.82

1.61 

1.81 

2.17 

3.90 

2.52 

6.50 

7.23

3.73 

5.55 

1.95

1.36 

1.48 

1.92 

1.87 

4.39 

5.10

7.48 

2.63 

1.93 

17.34 

11.83 

8.78 

6.46

1.80 

1.83 

5.16 

17.3 

31.6 

7.80 

4.39 

10.85 

4.34

1.51 

1.57 

2.38 

16.5 

31.8 

15.9 

5.55 

8.07

16.6

3.24 

4.66 

9.99 

15.7 

25.7 

11.3 

4.32

1.28 

1.31 

0.60

1.27 

0.89 

0.84 

1.02 

1.06 

2.26

1.20 

1.40 

1.01 

1.12 

1.15 

1.32 

1.40

1.54 

1.50 

1.21 

1.00 

0.66 

1.15 

1.32 

1.58 

1.40

1.37 

1.27 

1.21 

1.05 

0.50 

0.78 

1.21 

1.83

1.00

1.28 

1.05 

0.95 

0.89 

0.75 

1.32 

1.71

2.29 

2.05 

2.17

2.39 

2.30 

2.14 

2.16 

2.04 

2.41

2.53 

2.77 

2.65 

1.69 

1.93 

2.17 

2.41

2.47 

2.41 

2.18 

1.58 

0.83 

1.70 

1.81 

1.81 

1.81

2.51 

2.47 

2.34 

1.60 

0.80 

1.42 

1.69 

2.05

1.65

2.57 

2.54 

2.10 

1.64 

1.22 

1.63 

1.95

0.60 

0.72 

0.95

0.57 

0.58 

0.57 

0.60 

0.62 

0.57

0.55 

0.68 

0.65 

0.45 

0.52 

0.55 

0.58

0.60 

0.62 

0.57 

0.42 

0.20 

0.48 

0.52 

0.48 

0.48

0.62 

0.62 

0.62 

0.43 

0.23 

0.42 

0.62 

0.62

0.40

0.62 

0.60 

0.52 

0.40 

0.30 

0.43 

0.52

0.059 

0.061 

0.070

0.066 

0.065 

0.056 

0.047 

0.067 

0.067

0.054 

0.066 

0.061 

0.035 

0.039 

0.047 

0.047

0.066 

0.076 

0.059 

0.040 

0.017 

0.217 

0.074 

0.048 

0.045

0.071 

0.071 

0.062 

0.041 

0.019 

0.032 

0.050 

0.059

0.039

0.063 

0.052 

0.037 

0.037 

0.028 

0.041 

0.045

0.056 

0.135 

0.168

0.057 

0.049 

0.054 

0.065 

0.092 

0.051

0.052 

0.070 

0.051 

0.043 

0.051 

0.052 

0.048

0.057 

0.054 

0.046 

0.038 

0.019 

0.045 

0.066 

0.046 

0.056

0.043 

0.042 

0.039 

0.030 

0.016 

0.032 

0.078 

0.095

0.036

0.043 

0.036 

0.028 

0.027 

0.019 

0.035 

0.042

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D57
Supplementary table 5. Total chemical analysis of fine fraction by induction-coupled 

plasma spectroscopy Continued

No. Age

(ka)

215

216

217

218

219

220

221

222

225

226 

227

99a

229

230 

231

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000 

2,000

2,000

2,000

2,000

2,000 

2,000

Sample

number

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

D /-> *) (L-n

RC-26B

 nft O £ i>

RC-26B

Horizon

A

Bit

B21t

B22tca

B3tca

2K

2Clca

2C2ca 

3C3ca

B2tca

B31tca 

B32tca

£l> ll~a

2C2ca

Basal

depth

(cm)

6

11

20

29

40

68

145

247

 295

5

10 

16

25

36

48

oo 

+170

Percent of silt-plus-clay

Si02

66

62

60

60

39

15

34

45

62

A1203

11.02

12.93

12.99

12.76

8.32

3.08

6.16

9.70

13.40

Fe203

3.32

4.21

4.22

4.15

2.55

0.79

1.59

2.99

4.43

MgO

0.96

1.44

1.48

1.64

2.14

5.56

9.25

7.69

2.04

CaO

1.27

1.41

1.37

2.13

17.9

32.4

16.1

10.1

1.80

Na20

1.58

1.28

1.27

1.23

0.88

0.43

0.78

1.37

1.13

fraction

K20

2.43

2.47

2.36

2.23

1.42

0.46

0.89

1.36

2.30

Ti02

0.58

0.62

0.60

0.60

0.38

0.10

0.20

0.32

0.58

MnO

0.071

0.067

0.061

0.057

0.032

0.009

0.014

0.023

0.053

Zr02

0.054

0.042

0.042

0.041

0.027

0.009

0.018

0.027

0.043

*Percentages calculated from known percentages of oxides in the sand and the less-than-2mm 

fractions.

Supplementary table 6. Total chemical analysis of less-than-2-mm fraction by inductioncoupled plasma spectroscopy

[Analysts: P. H. Briggs and D. Fey under supervision of L. R. Layman, U. S. Geological Survey. 

 , not measured]

Methods 

Same methods as in supplementary table 5, except that sand fractions were not removed.

Basal 

depth

Percent of less-than-2 mm fraction

No. Age Sample

(ka) number Horizon (cm) Si02 A12 03 Fe 20 3 MgO CaO Na20 K20 Ti02 MnO Zr02

1 modern RC-R channel gravel 63 12.04 3.36 1.09 2.18 4.65 2.05 0.27 0.039 0.014

2 modern RC-M channel gravel 71 13.06 2.12 0.71 2.06 3.61 2.29 0.22 0.032 0.035

Mountain-front

3

4

5

6

7

8

9

10

11

12

13

14

15

16 

17

IS

7

7

7

7

7

7

20

20

20

20

20

20

20

20 

20

9n

RC-38

RC-38

RC-38

RC-38

RC-38

RC-38

RC-21

RC-21

RC-21

RC-21

RC-21

RC-21

DP 1 ^ Ko 1 J

RC-15

UP 1 S

K. \j L J 

PP-1 S

Al

2A31

2A32

2AC

3Clox

3C2ox

A

Bit

B2t

2B3t

3Clox

3C2ox

^

2B2t

onO £.0 J

9ri rtii9

22

33

46

85

+ 120

5

12

25

38

73

+110

23 

43

-I-AS

68

73

75

56

78

71

68

70

68

74

76

71

69

11.74

13.35

13.04

9.51

13.52

13.71

12.95

13.74

13.99

14.33

14.18

13.93

13.69

chronosequence

2.05

2.62

2.63

2.35

2.25

2.30

3.38

3.55

3.65

3.45

2.78

2.43

2.75

0.70

0.90

0.95

0.68

0.86

0.86

0.91

0.98

1.03

1.04

0.88

0.78

1.04

1.75

1.90

2.01

1.44

1.87

1.92

1.54

1.51

1.38

1.62

1.97

2.08

1.96

4.76

4.89

4.84

4.11

5.05

4.25

3.41

3.58

2.78

3.79

5.03

4.49

3.89

2.05

2.53

2.29

1.81

2.41

2.17

2.41

2.53

2.53

2.41

2.41

2.05

2.53

0.18

0.23

0.25

0.20

0.22

0.25

0.38

0.40

0.43

0.33

0.25

0.22

0.30

0.031

0.035

0.035

0.023

0.022

0.021

0.059

0.058

0.054

0.038

0.028

0.025

0.045

0.015

0.020

0.026

0.015

0.018

0.022

0.025

0.028

0.029

0.025

0.015

0.020

0.025

D58 Soil Chronosequences in the Western United States
Supplementary table 6. Total chemical analysis of less-than-2-mm fraction by 

induction-coupled plasma spectroscopy Continued

No. Age 

(ka)

19 

20 

21 

22 

23 

24 

25 

26

27 

28 

29 

30 

31 

32

33 

34 

35 

36 

37 

38 

39

40 

41 

42 

43 

44 

45 

46

47 

48 

49 

50 

51

52 

53 

54 

55 

56 

57

58 

59 

60 

61 

62 

63

120 

120 

120 

120 

120 

120 

120 

120

120 

120 

120 

120 

120 

120

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600

600 

600 

600 

600 

600

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Basal 

Sample depth 

number Horizon (cm)

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31

RC-17 

RC-17 

RC-17 

RC-17 

RC-17 

RC-17

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29

RC-16 

RC-16 

RC-16 

RC-16 

RC-16

RC-28 

RC-28 

RC-28 

RC-28 

RC-28 

RC-28

RC-14 

RC-14 

RC-14 

RC-14 

RC-14 

RC-14

Al 

A3 

Bit 

B21t 

B22t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bit 

2B2t 

2B3t 

2Cox

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

2B31t 

3B32t 

3Cox

8 

19 

32 

54 

81 

123 

145 

+200

9

20 

31 

50 

122 

+ 136

9 

17 

29 

53 

81 

170 

+250

9 

18 

30 

50 

79 

167 

+260

27 

47 

72 

127 

+ 197

7 

11 

17 

47 

141 

+270

17 

32 

44 

84 

144 

+ 164

Percent of less-than-2 mm fraction

Si02 A1203

64 

69 

66 

70 

66 

64 

70 

67

70

62 

69 

69 

61 

63 

65 

57

64 

64 

62 

62 

63 

64 

66

66

64

59

64 

61 

54 

63 

67

13.50 

14.01 

13.44 

13.99 

16.34 

15.58 

14.84 

14.33

13.74

13.25 

14.35 

14.63 

14.20 

15.16 

14.46 

12.85

14.35 

14.39 

14.56 

14.29 

14.74 

13.89 

14.42

15.61

15.71

12.44 

13.12 

13.25 

12.48 

13.71 

14.88

Fe 203

3.45 

3.40 

3.95 

3.45 

4.48 

4.16 

4.43 

3.98

3.49

3.10 

3.32 

4.26 

4.01 

3.43 

3.86 

3.48

4.31 

4.11 

4.33 

4.05 

5.41 

5.51 

4.41

4.49

3.72

3.13 

3.55 

3.26 

3.30 

3.36 

3.05

MgO

1.11 

1.01 

1.24 

1.11 

1.13 

1.19 

1.59 

1.48

0.98

.06 

.13 

.44 

.38 

.13 

.34 

1.46

1.56 

1.53 

1.56 

1.72 

1.67 

2.42 

2.12

1.69

1.01

0.83 

1.00 

0.96 

1.14 

1.28 

0.95

CaO Na2 0

1.92 2.87 

1.66 3.56 

1.44 3.19 

1.61 3.21 

1.97 3.33 

2.57 4.42 

2.59 4.27 

2.55 4.20

1.12 2.79

2.20 3.10 

2.04 3.76 

1.99 3.40 

1.90 3.33 

2.00 3.58 

2.08 3.60 

2.06 3.14

2.29 3.17 

2.17 3.44 

2.10 3.17 

2.13 3.32 

2.43 3.37 

2.76 3.34 

2.46 3.52

2.38 3.92

1.72 3.61

1.33 2.43 

1.37 2.29 

1.47 2.70 

1.73 2.95 

2.01 3.49 

2.15 4.08

K20 Ti02 MnO

2.53 0.35 

2.89 0.33 

2.53 0.38 

2.65 0.35 

2.29 0.40 

1.69 0.35 

1.93 0.35 

2.17 0.32

2.53 0.43

2.41 0.30 

2.65 0.28 

2.53 0.38 

2.17 0.33 

2.17 0.27 

2.05 0.33 

2.17 0.28

2.41 0.42 

2.53 0.37 

2.29 0.40 

2.17 0.37 

2.05 0.48 

2.05 0.47 

2.17 0.35

2.05 0.38

2.77 0.35

2.53 0.35 

2.29 0.38 

2.05 0.33 

1.93 0.28 

1.93 0.27 

2.65 0.30

0.065 

0.057 

0.067 

0.047 

0.039 

0.054 

0.056 

0.050

0.043

0.054 

0.053 

0.059 

0.038 

0.040 

0.067 

0.038

0.066 

0.066 

0.065 

0.056 

0.075 

0.074 

0.062

0.045

0.043

0.062 

0.056 

0.043 

0.047 

0.049 

0.036

Zr02

0.023 

0.021 

0.026 

0.023 

0.022 

0.017 

0.017 

0.016

0.032

0.019 

0.015 

0.020 

0.015 

0.015 

0.015 

0.012

0.026 

0.018 

0.018 

0.018 

0.020 

0.020 

0.013

0.026

0.026

0.017 

0.021 

0.016 

0.012 

0.009 

0.016

Transition chronosequence

64 

65 

66 

67

68 

69 

70 

71 

72

7 

7 

7

7

7 

7 

7 

7 

7

RC-40 

RC-40 

RC-40 

RC-40

RC-42 

RC-42 

RC-42 

RC-42 

RC-42

A 

Bs 

2Clox 

2C2ox

Al 

A3 

2Bs 

3Bb 

3Coxb

13

46 

65 

310

6 

37 

55 

73 

+200

69 

73 

75 

73 

76

10.87 

12.21 

12.91 

13.38 

14.22

2.60 

2.93 

3.13 

3.22 

2.40

0.93 

1.04 

1.11 

1.13 

0.98

1.61 3.34 

1.73 3.60 

1.75 3.75 

1.82 3.48 

2.27 4.85

2.29 0.32 

2.41 0.33 

2.41 0.35 

2.41 0.37 

2.41 0.22

0.044 

0.048 

0.040 

0.045 

0.035

0.026 

0.025 

0.025 

0.027 

0.014

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D59
Supplementary table 6. Total chemical analysis of less-than-2-mm fraction by 

induction-coupled plasma spectroscopy Continued

No.

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

Age

(ka)

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

Sample

number

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-12

RC-12

RC-12

RC-12

RC-12

RC-32

RC-32

RC-32

RC-32

RC-41

RC-41

RC-41

RC-41

RC-41

RC-41

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

Horizon

A

Bit

B2t

2B3t

2Clox

2C2ox

3Cca

3Cn

A

Bit

B2t

2B3t

2Cox

Ap

2B2tca

2B3tca

3Cca

A

Bit

B2t

2B31t

2B32t

2Cox

A

B2t

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

Basal

depth

(cm)

5

25

43

57

78

175

197

+240

9

17

39

62

+ 122

21

37

70

+80

8

17

28

51

65

+ 100

9

20

50

100

+ 180

6

18

45

63

109

230

+240

8

14

22

37

54

89

160

+210

5

10

18

32

54

135

225

+235

13

30

46

96

+ 126

Percent of less-than-2 mm fraction

Si02 A12 03 Fe' 203 MgO CaO Na20 K20 Ti02 MnO Zr02

65 14.67 4.55 1.36 1.76 2.52 2.53 0.43 0.056 0.029

70 10.15 2.93 0.75 1.33 2.47 2.17 0.33 0.056 0.029

72 11.85 3.39 0.80 1.16 2.51 2.41 0.43 0.057 0.031

70 14.22 4.45 1.08 1.09 2.06 2.41 0.43 0.045 0.026

71 14.63 3.42 0.95 1.54 3.33 2.41 0.30 0.034 0.018

67 14.12 3.38 1.16 1.78 3.54 2.17 0.27 0.041 0.018

66 13.27 2.12 0.68 1.75 4.34 2.17 0.15 0.031 0.010

66 15.18 3.93 1.19 1.75 3.22 2.65 0.40 0.101 0.024

D60 Soil Chronosequences in the Western United States
Supplementary table 6. Total chemical analysis of less-than-2-mm fraction by 

induction-coupled plasma spectroscopy Continued

No. Age 

(ka)

Basal 

depth

Percent of less-than-2 mm fraction

Sample depth/

number Horizon (cm) Si02 A12°3 Fe2°3 Mg° CaO TiO. MnO ZrO,,

129 945 RC-36 A 7

130 945 RC-36 Bit 16

131 945 RC-36 B2tca 25

132 945 RC-36 B3tca 35

133 945 RC-36 K 53

134 945 RC-36 2Clca 80

135 945 RC-36 3C2ca 103

136 945 RC-36 3C3ca 173

137 945 RC-36 3C4ca 200

138 945 RC-36 4C5ca 227 

139 945 RC-36 4C6ca +255

140 2,000 RC-33 Al 9

141 2,000 RC-33 A3 16

142 2,000 RC-33 Bit 24

143 2,000 RC-33 B2t 43

144 2,000 RC-33 2B3t/ca 58

145 2,000 RC-33 2K1 58

146 2,000 RC-33 2K2 92

147 2,000 RC-33 3Clca 180

148 2,000 RC-33 3C2ca +220

149 2,000 RC-8 A 8 

150 2,000 RC-8 B2t 22

151 2,000 RC-8 2B3tca 72

152 2,000 RC-8 2K 112

153 2,000 RC-8 2Cca +162

	Basin chronosequence

154 7 RC-46A Ap 20

155 7 RC-46A ACca 40

156 7 RC-46A 2Cgca 70

157 7 RC-46A 2Cox 98

158 7 RC-46A 3Cn +150

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

7 RC-46B Apca

7 RC-46B 2Cca

7 RC-46B 3Cn

20

20

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

RC-20 

RC-20 

RC-20 

RC-20 

RC-20 

RC-20

RC-4.3 

RC-43 

RC-43 

RC-43 

RC-43 

RC-43

RC-27 

RC-27 

RC-27 

RC-27 

RC-27 

RC-27 

RC-27

A

2Blt

2B2tca

2B3tca

3Clca

3C2ca

A

Bit

B2t

2B3tca

2Clca

3C2ca

A

2Blt

2B2t

2B3ca

3Clca

4C2ca

5C3ca

28

60

+ 150

9

15

32

50

130

+330

18 

33 

44 

65 

98 

+200

6

11

19

34

74

147

+225

66 11.66 3.66

71 9.60 3.42

71 12.23 3.23

1.82

1.84

1.36

3.38

4.35

2.85

1.33

1.55

2.79

2.17

1.93

2.17

0.52

0.53

0.38

0.056 0.047

0.053 0.093

0.048 0.042

75 11.08 3.36 0.91 1.37 2.44 2.29 0.38 0.057 0.033

73

72

77

73

71

12.67

13.42

11.93

9.45

13.95

4.39

4.42

3.65

3.10

2.70

1.23

1.19

0.91

0.71

1.01

1.45

1.73

1.80

1.89

2.28

2.28

2.80

3.17

2.65

3.98

2.29

2.29

2.17

1.81

2.41

0.40

0.35

0.30

0.23

0.20

0.063

0.061

0.061

0.058

0.040

0.032

0.024

0.027

0.020

0.013

62 10.93 3.66 1.82 5.94 1.44 2.29 0.45 0.048 0.038

66 11.64 4.11 1.44 2.38 1.62 2.29 0.48 0.053 0.045

61 14.18 5.41

55 9.57 3.29

61 10.08 3.22

62 10.98 3.38

66 10.23 3.68

1.74

1.97

2.16

3.13

1.86

2.06

13.4

8.91

7.16

6.42

1.48

1.29

1.37

1.71

1.94

2.53

1.69

1.81

2.05

1.93

0.53

0.38

0.42

0.42

0.33

0.062 0.036

0.040 0.032

0.039 0.040

0.044 0.036

0.057 0.020

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D61
Supplementary table 6. Total chemical analysis of less-than-2-mm fraction by 

induction-coupled plasma spectroscopy Continued

No. Age 

(ka)

181 

182 

183 

184 

185 

186 

187 

188 

189 

190 

191

192 

193 

194 

195 

196 

197 

198 

199

200 

201 

202 

203 

20-4 

205 

206 

207

208 

209 

210 

211 

212 

213 

214

215 

216 

217 

218 

219 

220 

221 

222 

223

224 

225 

226 

227 

228 

229 

230 

231

415 

415 

415 

415 

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600 

600

945 

945 

945 

945 

945 

945 

945 

945

945 

945 

945 

945 

945 

945 

945

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Sample 

number

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B

Horizon

A 

Bltca 

B2tca 

B3tca 

2K 

3Clca 

3C2ca 

4C3ca 

5C4ca 

5C5ca 

5C6ca

A 

Bit 

B2tca 

B3tca 

K 

2Clca 

2C2ca 

2C3ca

Ac a 

Bltca 

B2tca 

B3tca 

2K 

2Clca 

2C2ca 

3C3ca

Ac a 

Bltca 

B21tca 

B22tca 

B31tca 

2B32tca 

2Cca

A 

Bit 

B21t 

B22tca 

B3tca 

2K 

2Clca 

2C2ca 

3C3ca

A 

Bit 

B2tca 

B31tca 

B32tca 

2K 

2Clca 

2C2ca

Basal

depth 

(cm)

3 

7 

14 

29 

60 

121 

170 

226 

255 

310 

+320

4 

9 

19 

30 

45 

62 

87 

+300

4 

9 

15 

25 

49 

65 

91 

+ 130

6 

13 

19 

27 

45 

86 

+ 120

6 

11 

20 

29 

40 

68 

145 

247 

295

5 

10 

16 

25 

36 

48 

88 

+ 170

Percent of less-than-2 mm

Si02

64 

66 

60 

46 

46 

63 

69 

66 

70

60 

63 

60 

47 

29 

55 

64 

71

46

64 

58 

54 

46 

36 

59 

66

70 

65 

66 

65 

46 

33 

56 

66

67

A12°3

11.04 

11.27 

11.08 

9.15 

8.75 

12.12 

12.40 

12.08 

13.02

11.80 

12.72 

12.95 

9.17 

5.67 

10.96 

11.81 

12.27

9.00

11.19 

11.68 

10.66 

8.47 

7.16 

10.42 

10.23

11.00 

11.98 

12.31 

11.89 

8.58 

5.90 

9.77 

11.42

12.57

Fe2°3

3.25 

3.20 

3.16 

2.07 

1.33 

3.25 

2.85 

2.30 

2.56

4.05 

4.45 

4.59 

3.06 

1.75 

2.78 

5.11 

2.83

3.03

3.69 

3.95 

3.53 

2.70 

2.32 

3.30 

3.16

2.53 

3.12 

3.35 

3.06 

2.09 

1.10 

1.42 

1.39

3.65

MgO

1.13 

1.13 

1.28 

1.06 

1.21 

2.29 

2.22 

2.37 

1.59

1.36 

1.51 

1.77 

2.16 

2.55 

2.80 

2.34 

1.08

1.87

1.48 

1.66 

2.02 

3.67 

2.60 

4.36 

3.98

0.78 

1.08 

1.23 

1.26 

2.07 

4.81 

4.41 

1.54

1.56

CaO

1.87 

2.08 

6.21 

17.8 

19.7 

4.90 

3.08 

5.79 

2.80

1.43 

1.54 

2.29 

14.7 

28.1 

9.82 

2.87 

2.06

16.9

3.17 

4.35 

9.27 

13.9 

22.4 

6.67 

2.80

1.31 

1.31 

1.33 

1.86 

16.6 

23.9 

7.54 

2.41

1.72

Na20

1.86 

2.09 

1.91 

2.05 

2.35 

2.52 

2.74 

2.98 

3.42

1.48 

1.50 

1.40 

1.21 

0.88 

2.41 

3.13 

3.58

1.83

1.51 

1.24 

1.17 

1.19 

1.15 

2.21 

2.30

2.33 

2.06 

1.94 

2.14 

1.55 

1.55 

2.82 

3.57

1.90

fraction

K20

2.41 

2.41 

2.17 

1.45 

1.81 

2.05 

2.05 

2.05 

2.29

2.41 

2.41 

2.29 

1.69 

0.96 

1.81 

2.05 

2.41

1.69

2.29 

2.29 

2.05 

1.57 

1.33 

1.93 

1.93

2.29 

2.41 

2.53 

2.17 

1.57 

1.20 

1.93 

2.17

2.53

Ti02

0.42 

0.43 

0.40 

0.25 

0.15 

0.32 

0.28 

0.27 

0.22

0.48 

0.50 

0.50 

0.37 

0.22 

0.32 

0.65 

0.33

0.37

0.45 

0.45 

0.42 

0.33 

0.28 

0.35 

0.32

0.38 

0.40 

0.42 

0.40 

0.27 

0.13 

0.18 

0.12

0.48

MnO

0.059 

0.057 

0.047 

0.027 

0.017 

0.308 

0.080 

0.036 

0.030

0.058 

0.059 

0.054 

0.038 

0.018 

0.028 

0.057 

0.035

0.039

0.050 

0.040 

0.036 

0.032 

0.028 

0.043 

0.038

0.058 

0.052 

0.054 

0.045 

0.028 

0.017 

0.021 

0.017

0.043

Zr02

0.033 

0.036 

0.029 

0.017 

0.011 

0.022 

0.030 

0.021 

0.028

0.029 

0.030 

0.029 

0.022 

0.015 

0.025 

0.034 

0.031

0.023

0.026 

0.025 

0.023 

0.017 

0.013 

0.018 

0.018

0.032 

0.029 

0.027 

0.024 

0.018 

0.007 

0.011 

0.008

0.033

D62 Soil Chronosequences in the Western United States
Supplementary table 7, part 1. Horizon weights of sand, silt, clay, carbon, organic phosphorus, CaCOg, 

and clay minerals

[Analyst: Marith C. Reheis, U.S. Geological Survey. , not measured]

Methods

2

Profile weights of soil properties (g/cm /column of soil) are calculated from the property percentage, bulk 

density, and texture of each horizon. The pedogenic increase from the amount of the property in the parent material 

is calculated by estimating the property percentage, bulk density, and texture in the original deposit (method 

modified from Machette, 1978 and 1985). Weights are calculated for each horizon, summed to give the total profile 

weight in a soil, and standardized to 250 cm depth (in the regression equations in the text) to eliminate bias caused 

by different depths of sampling (backhoe pits versus hand-dug holes).

Two basic equations are used to calculate pedogenic increase for clay, silt, organic phosphorus, and CaCOo* 

Equation 1 is used to calculate pedogenic increase in horizon weight of clay and silt (substitute appropriate silt 

percentages when calculating silt weights):

, , clay% 100 - salts% i clay% 100 - i salts% 1. g clay = ((^_)(BDf)( __ )(H)) _ (( --"' )(1 BDf)( ) (H))

where BDf is the bulk density of the <2-mm fraction, H is the horizon thickness, salts include organic matter, CaCOg, 

and gypsum (if present), and the letter "i" designates an estimate of the parent-material state. The parent-material 

CaC03 content of all Rock Creek soils except soils RC-27, RC-36, and RC-25 is assumed to be zero. This equation 

includes a factor to account for salts and organic matter because particle size is measured on an organic-free and 

salt-free basia. Equation 2 is used to calculate pedogenic weights of organic phosphorus (phos) and CaCOg (again, 

substitute CaCO^ percentages in place of organic phosphorus percentages when calculating CaCO^ weights):

, , _ phos% i phos%

2 ' g ph° S " « 10<n(BDf)(H)) - (( 100 ><1 BDf)(H))

Profile weights for sand, carbon, clay minerals, and major oxides are not corrected for the estimated parent 

material contents. Values for sand are calculated using the first term of equation 1 above, substituting the 

appropriate sand percentages for clay percentages. Values for carbon and major oxides of the less-than-2 mm fraction 

(supplementary table 7, part 2) are calculated using the first term of equation 2 above, substituting the appropriate 

property percentages for the percentage of organic phosphorus. Horizon weights for clay minerals are calculated by 

equation 3:

<r /-!= m<r. Q^=,i - clay mineral^ clay% 100 - salts% g clay mineral / * \/ * wu wun-irw \ ( 100 )( 100 )(H)(BDf)( 10Q )

2 Basal _________________horizon weight (g/cm /horizon column)

Age Sample depth Organic Kaoli- Chlor- Mixed-layer SmecNo. (ka) number Horizon (cm) Sand Silt Clay Carbon phosphorus CaCCU nite ite Mica smectite-illite tite

1 modern RC-R channel gravel

2 modern RC-M channel gravel

Mountain-front chronosequence

3

4

5

6

7

8

9

10

11

12

13

14 

15

16

17

1 D10

19

20

21

22

23

24

25

26

7

7

7

7

7

7

20

20

20

20

20

20 

20

20

20

20

120

120

120

120

120

120

120

120

RC-38

RC-38

RC-38

RC-38

RC-38

RC-38

RC-21

RC-21

RC-21

RC-21

RC-21

RC-21

PP 1 ^

KL. 1 J

T) p _ 1 C K.L. i j 

pp i ^ KL. 1 J 

pp 1 ^ KL. 1 J

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

RC-31

Al

2A31

2A32

2AC

3Clox

3C2ox

A

Bit

B2t

2B3t

3Clox

3C2ox 

A

9TJ9«- f.oL t 

9TJ 1 £.OJ

2Cox 

Al

A3

Bit

B21t

B22t

2B31t

2B32t

2Cox

9

22

33

46

85

+120

5

12

25

38

73

+110

23 

43

i /: o

+OO 

8

19

32

54

81

123

145

+200

5.8

7.9

6.9

10.

8.9

10.

3.6

5.7

8.1

9.5

8.9

9.7

4.2

6.4

5.9

16.

18.

37.

8.3

29.

-0.05

.32

.69

.85

0

0

.42

.81

.80

1.6

0

0

.42

.97

1.8

3.9

1.9

2.1

.49

0

-0.10

.15

.11

.05

0

0

.12

.46

1.1

1.2

0

0

.12

.40

1.0

2.4

3.5

1.0

0.15

0

0.21

.13

.032

.029

.016

.033

.17

.26

.33

.083

.016

.015

.26

.25

.21

.48

.35

.069

.005

.006

0.0014

.0024

.0015

.0019

.0004

0

.0024

.0026

.0027

.0009

.0006

.0001

0.0020

0.0036

0.0018

0.0031

0.0039

0.0018

0.0017

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.064

.072

.046

.025

.011

.11

.39

.68

.46

.006

"

.18

.25

.46

.84

.56

.25

.013

.007

0.026

.036

.005

.008

.004

.025

.058

.054

.040

.001

"

.041

.045

.051

.34

.20

.19

.008

.035

0.10

.15

.043

.046

.038

.14

.45

.68

.24

.010

.26

.50

.32

.80

1.1 '.54

.042

.17

0.029

.069

.12

.16

.12

.50

.38

.89

.40

.054

.17

.26

.59

.61

2.3

1.6

.25

.26

0.017

.032

.022

.023

.009

.049

.17

.41

.56

.003

.027

.090

.25

.99

.46

.22

.046

.071

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D63
Supplementary table 7, part 1.

and clay minerals Continued

Horizon weights of sand, silt, clay, carbon, organic phosphorus, CaCOg,

No.

27 

28 

29 

30 

31 

32

33 

34 

35 

36 

37 

38 

39

40 

41 

42 

43 

44 

45 

46

47 

48 

49 

50 

51

52 

53 

54 

55 

56 

57

58 

59 

60 

61 

62 

63

64 

65 

66 

67

68 

69 

70 

71 

72

73 

74 

75 

76 

77 

78 

79 

80

81 

82 

83 

84 

a^

Age 

(ka)

120 

120 

120 

120 

120 

120

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600

600 

600 

600 

600 

600

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

7 

7 

7 

7

7

7 

7 

7 

7

20 

20 

20 

20 

20 

20 

20 

20

120 

120 

120 

120 

i 9n

Sample 

number

RC-17 

RC-17 

RC-17 

RC-17 

RC-17 

RC-17

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29

RC-16 

RC-16 

RC-16 

RC-16 

RC-16

RC-28 

RC-28 

RC-28 

RC-28 

RC-28 

RC-28

RC-14 

RC-14 

RC-14 

RC-14 

RC-14 

RC-14

RC-40 

RC-40 

RC-40 

RC-40

RC-42 

RC-42 

RC-42 

RC-42 

RC-42

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22 

RC-22

RC-12 

RC-12 

RC-12 

RC-12

DT-l 9

Basal 

depth 

Horizon (cm)

A 

Bit 

B2t 

B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bit 

2B2t 

2B3t 

2Cox

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bs 

2Clox 

2C2ox

Al 

A3 

2Bs 

3Bb 

3Coxb

A 

Bit 

B2t 

2B3t 

2Clox 

2C2ox 

3Cca 

3Cn

A 

Bit 

B2t 

2B3t

9

20 

31 

50 

122 

+136

9

17 

29 

53 

81 

170 

+250

9 

18 

30 

50 

79 

167 

+260

27 

47 

72 

127 

+197

7 

11 

17 

47 

141 

+270

17 

32 

44 

84 

144 

+164

13 

46 

75 

310

6 

37 

55 

73 

+200

5 

25 

43 

57 

78 

175 

197 

+240

9 

17 

39 

62

4.1 99

horizon weight

Sand

6.0 

6.4 

8.5 

16. 

20. 

69. 

24.

2.2 

4.0 

8.2 

9.6 

15. 

76. 

52.

2.5 

3.1 

4.4 

8.7 

37. 

67.

12. 

12. 

11. 

26. 

36. 

10.

10. 

19. 

9.4 

103

2.3 

8.4 

14. 

8.8 

56.

3.0 

11. 

8.6 

18. 

32. 

31. 

7.9 

14.

2 (g/cm /horizon column)

Organic Kaoli- Chlor- Mixed-layer SmecSilt Clay Carbon phosphorus CaCOg nlte ite Mica smectite-lllite tlte

-.14 -.37 

.04 -.13 

1.4 .71 

.92 2.4 

.69 2.7 

1.7 4.5 

0 .57

.01 0 

.33 .16 

1.5 1.1 

1.4 1.1 

1.2 .84 

3.4 2.6 

0 4.3

-.07 .0 

.07 .07 

.19 .29 

.77 .92 

1.5 2.8 

0 2.9

-1.1 1.2 

-.51 2.2 

-.52 2.0 

1.2 3.0 

0 2.9 

0 .19

Transition

-.31 .55 

3.7 1.2 

0 0 

0 0

-.15 -.23 

-1.5 -.96 

-0.22 .79 

2.2 .73 

0 0

.38 .05 

.83 .39 

2.9 1.6 

2.2 1.4 

1.3 1.4 

0 0 

0 0 

0 0

.45 

.24 

.25 

.32 

.21 

.083 

.011

.10 

.11 

.24 

.25 

.33 

0 

0

.11 

.075 

.13 

.064 

.086 

.060

.0028 

.0025 

.0025 

.0035 

.0027 

0 

.0010

.0010 

.0013 

.0035 

.0018 

.0026 

.0080 

0

.0074 

.0056 

.0209 

.0047 

.0064 

0

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

.071 

.13 

.23 

.073 

.17 

.35 

.022

.084 

.092 

.49 

.48 

.30 

.20 

.19

.49 

.67 

.90 

.50 

.049 

.021

.088 

.070 

.031 

.073 

.083 

.18 

.044

.012 

.018 

.038 

.13 

.068 

.14 

.062

0 

0 

0 

0 

0 

0

.64 

.58 

.79 

.55 

.42 

2.0 

.24

.15 

.33 

.75 

.80 

1.1 

1.3 

1.2

1.8 

1.2 

.56 

2.2 

.25 

.08

.018 

.00 

.32 

2.4 

2.7 

4.9 

1.6

.088 

.11 

.30 

.13 

.36 

3.4 

3.1

1.6 

2.4 

2.0 

1.3 

2.6 

.28

.071 

.039 

.11 

.44 

.46 

.88 

.22

.046 

.062 

.21 

.36 

.27 

1.1 

1.1

0 

.22 

.30 

.60 

.99 

.06

chronosequence

.16 

.33 

.26 

.042 

.13

.22 

.38 

.22 

.43 

.029 

.052 

.050 

.006

0 

0 

0 

0

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

.28 

0

.11 

.34 

.82 

.52 

.52

.21 

.52 

.46 

.29 

.38 

.42

.025 

.074 

.11 

.066 

0

0.038 

0.16 

0 

0.13 

0.18 

0

.11 

.44 

.93 

.50 

.36

.34 

.97 

.64 

1.0 

.79 

.51

.071 

.23 

0 

0 

.037

.11 

.81 

1.3 

.33 

.68 

.78

.039 

.14 

.38 

.24 

.32

.053 

.16 

.15 

.42 

.51 

.40

D64 Soil Chronosequences in the Western United States
Supplementary table 7, part 1.

and clay minerals Continued

Horizon weights of sand, silt, clay, carbon, organic phosphorus, CaCOg,

No.

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

Age

(ka)

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample

number

RC-32

RC-32

RC-32

RC-32

RC-41

RC-41

RC-41

RC-41

RC-41

RC-41

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-8

RC-8

RC-8

RC-8

RC-8

Horizon

Ap

2B2tca

2B3tca

3Cca

A

Bit

B2t

2B31t

2B32t

2Cox

A

B2t

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

A

Bit

B2tca

B3tca

K

2Clca

3C2ca

3C3ca

3C4ca

4C5ca

4C6ca

Al

A3

Bit

B2t

2B3t/ca

2K1

2K2

3Clca

3C2ca

A

B2t

2B3tca

2K

2Cca

Basal

depth

(cm)

21

37

70

+80

8

17

28

51

65

+ 100

9

20

50

100

+180

6

18

45

63

109

230

+240

8

14

22

37

54

89

160

+210

5

10

18

32

54

135

225

+235

13

30

46

96

+ 126

7

16

25

35

53

80

103

173

200

227

+255

9

16

24

43

58

58

92

180

+220

8

22

72

112

+ 162

2 horizon weight (g/cm /horizon column)

Sand

7.2

5.7

23.

3.2

3.4

4.0

4.3

10.

7.1

12.

4.0

6.6

21.

5.3

7.1

61.

5.6

4.3

5.7

8.7

7.3

6.5

24.

18.

4.0

3.7

4.7

8.7

6.2

23.

28.

3.2

1.9

3.6

3.3

4.4

3.6

10.

4.8

7.1

16.

9.7

6.4

1.2

2.1

2.9

9.8

2.9

2.9

12.

37.

11.

Silt

2.7

.67

4.3

.08

-.11

2.0

1.0

0

0

0

-.01

.73

0

.99

.67

.79

.67

.45

.77

.90

.49

3.0

0

0

-.22

-.36

.29

.19

.00

1.4

0

0

.67

.33

.46

1.9

3.0

4.8

0

0

0

0

0

.20

.79

.11

-.27

.06

.06

.13

0

0

Organic

Clay Carbon phosphorus CaCO.,

12.

2.0

5.4

.09

-.24

1.2

2.5

2.1

1.3

.44

.16

1.3

4.1

1.9

1.2

1.5

.51

.31

.57

1.8

.39

.30

0

0

-.07

.70

1.4

.53

.17

.81

0

0

.28

1.7

1.2

1.8

2.6

3.3

0

0

0

0

0

.25

1.4

2.4

8.3

0.52

0.52

1.3

4.3

0

.77

.16

.77

.003

0.4

.19

.20

.27

.011

.008

.22

.25

.69

.25

.14

.007

.22

.20

.20

.27

.10

.023

.020

.002

_

.009

.19

.12

.12

.13

.045

.32

1.8

.46

.010

.008

.050

.12

.20

.49

.10

.066

.25

.15

.006

0

.06

1.6

.01

.0035 0

.0023 0

.0025 0

.0019 0

.0002 0

.0006 0

0

0

.07

8.7

6.9

11.

0

0

0

0

0.02

3.5

4.3

1.3

0

0

.28

7.8

3.8

9.3

4.2

.17

0

0

.03

5.0

13.

6.3

.05

.22

1.0

.36

1.8

0

0

0

0

0.86

0.86

3.9

2.0

.37

Kaolinite

2.1

.65

2.5

.064

.37

.85

1.3

1.2

.59

.20

.21

.60

2.0

.76

.45

1.0

.34

.30

.25

.49

.11

.065

.17

.29

.60

.33

.83

1.1

2.0

2.2

2.7

.16

.17

.50

.44

2.8

.13

.13

.24

.51

.14

Chlorite

.60

.084

.38

.008

0

.034

.032

.062

.064

.017

.040

.078

.22

.096

.14

.18

0

.068

.12

.070

.050

.020

.040

.031

.023

.12

.13

.19

.023

.36

 -

.48

.015

.051

.089

.067

.22

0

0

0

0

0

Mixed-layer SmecMica smectite-illite tite

1.8-

.56

1.7

.036

.22

.33

.35

.25

.21

.074

.38

.42

1.2

.41

.39

.84

.48

.37

.52

1.62

.23

.075

.10

.21

.60

.30

.45

.47

1.2

1.4

1.60

.12

.15

.55

.50

2.4

.13

.13

.26

.29

.16

7.6

1.0

1.4

.060

.020

.36

1.2

1.3

.55

.46

.33

1.2

1.9

.83

.62

.40

.65

.27

.67

.67

.39

.065

.097

.013

.90

.28

.22

.063

.87

0

0

0

.20

.32

2.0

3.7

.65

.65

1.0

4.7

1.5

3.0

.45

1.7

.02

.053

.16

.29

.31

.21

.074

.050

.29

1.7

.99

.71

1.2

.13

.14

.12

.49

.22

.065

.17

.094

.21

.50

.31

.75

1.3

2.7

3.20

.21

.051

.32

.34

2.1

.11

.11

.86

1.7

.47

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D65
Supplementary table 7, part 1. Horizon weights of sand, silt, clay, carbon, organic phosphorus, CaCO3 , 

and clay minerals Continued

No.

Age 

(ka)

Sample 

number Horizon

Basal

depth 

(cm)

9

horizon weight (g/cm /horizon column)

Sand Silt

Organic 

Clay Carbon phosphorus CaCOg

Kaoli- Chlor- Mixed-layer Smecnite ite Mica smectite-illite tite

Basin chronosequence

154 

155 

156 

157 

158

159 

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191 

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

7 

7 

7 

7 

7

7 

7

7

20

20

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415 

600

600

600

600

600

600

600

600

945

945

945

945

945

945

945

945

945

945

945

945

945

945

945

RC-46A Ap 

RC-46A ACca 

RC-46A 2Cgca 

RC-46A 2Cox 

RC-46A 3Cn

RC-46B Apca 

RC-46B 2Cca

RC-46B

RC-20

RC-20

RC-20

RC-20

RC-20

RC-20

RC-43

RC-43

RC-43

RC-43

RC-43

RC-43

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

RC-23

pp OQ l\\j £. J

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-24

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-25

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

RC-44

3Cn

A

2Blt

2B2tca

2B3tca

3Clca

3C2ca

A

Bit

B2t

2B3tca

2Clca

3C2ca

A

2Blt

2B2t

3B3ca

3Clca

4C2ca

5C3ca

A

Bltca

B2tca

B3tca

2K

3Clca

3C2ca

4C3ca

5C4ca

5C5ca

5C6ca 

A

Bit

B2tca

B3tca

K

2Clca

2C2ca

2C3ca

Aca

Bltca

B2tca

B3tca

2K

2Clca

2C2ca

3C3ca

Aca

Bltca

B21tca

B22tca

B31tca

2B32tca

2Cca

20 

40 

70 

98 

+ 150

28 

60

+150

9

15

32

50

130

+330

18

33

44

65

98

+200

6

11

19

34

74

147

+225

3

7

14

29

60

121

170

226

255

310

+320

4

9

19

30

45

62

87

+300

4

9

15

25

49

65

91

+ 130

6

13

19

27

45

86

+120

6.7 

17. 

13. 

20. 

12.

9.6 

15.

21.

6.5

4.3

9.6

11.

33.

51.

7.6

9.1

6.1

7.1

13.

35.

2.9

1.4

1.5

6.7

23.

43.

22.

.94

1.3

1.1

4.1

13.

9.9

11.

22.

9.1

15.6

1.3

1.6

2.2

2.1

2.2

5.3

7.8

73.

1.6

1.3

1.5

2.0

5.7

6.6

9.2

33.

1.9

1.9

.69

2.2

2.3

9.2

7.6

1.1

.13

.65

0

0

0

-.05

-.55

.42

1.36

0

0

.40

.49

.30

.30

0

0

0

.61

1.1

.72

1.2

-.02

2.4

.75

0

0

0

1.0

1.5

2.1

2.1

.79

.38

.29

0

.13

-.18

-.14

.23

.34

.37

.10

0

.40

.24

.48

2.0

1.7

2.2

.65

-.37 

.76 

0 

0 

0

.63 

-.28

0

.89

1.6

2.2

.10

0

0

2.7

.02

2.2

.96

.03

0

.86

.46

1.3

.23

2.1

0

0

.16

.27

.39

.60

0

1.8

.33

0

0

0

1.1

1.7

3.2

1.3

.95

.50

0

0

.07

.18

.25

.41

.39

.08

0

0

.67

1.4

.49

1.2

1.0

.39

0

.53 

.12 

.54 

.090 

.017

.71 

.11

.029

.25

.12

.11

.065

.026

.011

.65

.43

.35

.098

.033

.019

_

.13

.084

.089

.14

.027

.029

.015

.012

.005

.018

.13

.17

.20

.13

.13

.025

.013

0

_

.14

.18

.071

.16

.21

.059

.019

0

.0023

.0043

.0017

.0009

.0004

__

_

--

.0008

.0006

.0010

.0042

.0033

.0013

.0016

.0013

.0037

.0045

.0013

.0011

.0001

--

__

.0012

.0020

.0009

.0025

.0029

.0011

.0003

.43 

1.7 

1.5 

.18 

.01

1.1 

.71

.01

0

0

.35

.13

4.9

.16

0

0

0

.88

.32

.42

.61

0

.02

2.8

5.1

7.2

1.9

0

.03

1.4

4.3

9.9

1.1

4.3

1.3

2.4

1.3

0

0

.19

3.3

6.9

1.3

.20

1.9

.14

.72

1.5

2.9

10.

4.8

1.3

.60

.19

.43

.50

2.6

4.8

1.8

.26

.71

.53

1.0

.35

.60

.12

.10

.15

.37

.28

.49

.16

.20

.48

.88

.78

.42

.19

.48

.44

.21

.11

.46

.10

.006

0 .67

0 .33

0 .50

.010 .19

0 .34

0 .083

.011 .13

.007 .15

.022 .079

.010 .063

0 .19

0 .044

-- 

.033 .33

.048 .46

.046 1.4

.049 .46

.037 .22

.011 .042

.12 .45

.12 .23

.026 .18

.060 .22

.066 .21

.017 .033

.004 .006

.50

1.3

.71

.15

.23

.33

.23

.23

.43

.26

.67

.18

.89

1.1

1.7

.61

.55

.34

.12

1.4

.31

.66

.16

.27

.072

.28

.35

.87

.29

.71

.059

.071

.15

.22

.43

1.0

.36

.22

.31

.65

.53

.59

.46

.19

.19

.12

.45

.42

.43

.098

D66 Soil Chronosequences in the Western United States
Supplementary table 7, part 1. Horizon weights of sand, silt, clay, carbon, organic phosphorus, CaCO3 , 

and clay minerals Continued

No.

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

Age 

(ka)

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample 

number

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26A

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

RC-26B

Horizon

A

Bit

B21t

B22tca

B3tca

2K

2Clca

2C2ca

3C3ca

A

Bit

B2t

B31tca

B32tca

2K

2Clca

2C2ca

Basal 

depth 

(cm)

6

11

20

29

40

68

145

247

295

5

10

16

25

36

48

88

+170

2 horizon weight (g/cm /horizon column)

Sand

2.9

1.8

4.6

3.9

2.8

6.9

25.

62.

35.

3.7

2.4

3.2

3.8

3.8

4.6

18.

38.

Silt

1.0

.23

1.3

.67

1.2

.78

2.8

.71

0

.18

-.05

.04

1.3

.64

.35

1.1

1.2

Organic Kaoli- Chlor- Mixed-layer SmecClay Carbon phosphorus CaCO, nite ite Mica smectite-illite tite

.07

.60

2.0

1.3

1.1

1.0

.40

0

0

.19

.76

.78

1.4

.68

.35

.57

0

.12

.11

.27

.23

.14

.053

.052

.007

.004

 -

 

.0009

.0008

.0027

.0016

.0032

.0062

.0028

0

.0025

0 .13 .067 .28 .19

0 .28 .023 .12 .61

0 .53 .067 .50 1.40

.11 .30 .20 .79 .27

3.0

11. .029 .014 .058 .65

6.0 .025 0 .025 .56

1.4

.26

0

0

0

5.2

3.9

4.7

9.2

4.2

.082

.14

.83

.92

.71

.61

"

Supplementary table 7, part 2. Horizon weights of major oxides plus zirconium in the less-than-2- 

mm fraction

[Analyst: M. C. Reheis, U. S. Geological Survey. , not measured; tr, trace]

Methods

Horizon weights for element oxides are calculated using the first term in equation 2 given in 

supplementary table 7, part 1. Parent material amounts are not subtracted.

2

Basal ____horizon weight (g/cm /horizon in less-than-2 mm fraction)_____ 

No. Age Sample depth

(ka) number Horizon (cm) Si02 A1 2°3 Fe 2°3 Mg° Ca ° Na2° K2° Ti°2 Mn° Zr °2

1 modern RC-R channel gravel

Mountain-front chronosequence

3

4

5

6

7

8

9

10

11

12

13

14 

15

16 

17

is

7

7

7

7

7

7

20

20

20

20

20

20 

20

20 

20

?n

RC-38

RC-38

RC-38

RC-38

RC-38

RC-38

RC-21

RC-21

RC-21

RC-21

RC-21

RC-21

RC-15

nr-i 1

Al

2A31

2A32

2AC

3Clox

3C2ox

A

Bit

B2t

2B3t

3Clox

3C2ox

2B2t 

9110

7P,-.ir

9

22

33

46

85

+ 120

5

12

25

38

73

+ 110

23

-I-AR

5.0

7.1

6.2

6.6

8.2

9.0

4.6

7.5

11.

11.

7.2

7.1

0.86

1.3

1.1

1.1

1.4

1.7

.87

1.5

2.2

2.1

1.3

1.4

0.15

.26

.22

.28

.24

.29

.23

.38

.58

.50

.26

.24

0.051

.088

.078

.080

.091

.11

.061

.11

.17

.15

.083

.078

0.13

.19

.17

.17

.20

.24

.10

.16

.22

.24

.19

.21

0.35

.48

.40

.48

.53

.54

.23

.38

.45

.55

.48

.45

0.15

.25

.19

.21

.25

.27

.16

.27

.41

.35

.23

.21

0.013

.022

.021

.023

.023

.032

.026

.043

.069

.048

.024

.022

0.002

.003

.003

.003

.002

.003

.004

.006

.009

.006

.003

.002

0.001

.002

.002

.002

.002

.003

.002

.003

.005

.004

.001

.002

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D67
Supplementary table 7, part 2. Horizon weights of major oxides plus zirconium in the less-than-2- 

mm fraction Continued

No. Age 

(ka)

19 

20 

21 

22 

23 

24 

25 

26

27 

28 

29 

30 

31 

32

33 

34 

35 

36 

37 

38 

39

40 

41 

42 

43 

44 

45 

46

47 

48 

49 

50 

51

52 

53 

54 

55 

56 

57

58 

59 

60 

61 

62 

63

120 

120 

120 

120 

120 

120 

120 

120

120 

120 

120 

120 

120 

120

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600

600 

600 

600 

600 

600

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Basal

Sample depth 

number Horizon (cm) Si02

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31 

RC-31

RC-17 

RC-17 

RC-17 

RC-17 

RC-17 

RC-17

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30 

RC-30

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29 

RC-29

RC-16 

RC-16 

RC-16 

RC-16 

RC-16

RC-28 

RC-28 

RC-28 

RC-28 

RC-28 

RC-28

RC-14 

RC-14 

RC-14 

RC-14 

RC-14 

RC-14

Al 

A3 

Bit 

B21t 

B22t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

2B32t 

2Cox

Al 

A3 

Bit 

B2t 

2B31t 

3B32t 

3Cox

A 

Bit 

2B2t 

2B3t 

2Cox

A 

Bit 

B2t 

2B31t 

2B32t 

2Cox

A 

Bit 

B2t 

2B31t 

3B32t 

3Cox

8 4.2 

19 6.9 

32 7.0 

54 18. 

81 18. 

123 30. 

145 6.8 

+200 21.

9

20 

31

50 

122

i 1 O/l

9 5.6 

17 6.1 

29 8.9 

53 14. 

81 17. 

170 54. 

+250 16.

9 2.3 

18 3.7 

30 8.2 

50 9.3 

79 14. 

167 60. 

+260 41.

27

47

72

127

+197 

7

11

17 3.9

47

141 

+270

17 12. 

32 13. 

44 11. 

84 19. 

144 28. 

+164 7.8

horizon weight

A12°3

.88 

1.4 

1.4 

3.7 

4.5 

7.2 

1.4 

4.6

1.2 

1.3 

1.9 

3.2 

4.2 

12. 

3.5

.50 

.84 

1.9 

2.1 

3.2 

13. 

8.9

.96

2.5 

2.8 

2.4 

4.4 

6.0 

1.7

Transition

64 

65 

66 

67

68 

69 

70 

71 

72

7 

7 

7 

7

7 

7 

7 

7 

7

RC-40 

RC-40 

RC-40 

RC-40

RC-42 

RC-42 

RC-42 

RC-42 

RC-42

A 

Bs 

2Clox 

2C2ox

Al 

A3 

2Bs 

3Bb 

3Coxb

13

46

65 

310 

6 2.9 

37 10. 

55 17. 

73 9.9 

+200 45.

.45 

1.7 

2.9 

1.8 

8.5

Fe 2 0 3

.22 

.34 

.42 

.91 

1.2 

1.9 

..43 

1.3

.28 

.29 

.55 

.91 

.94 

3.2 

.95

.15 

.24 

.57 

.61 

1.2 

5.1 

2.7

.23

.64 

.75 

.60 

1.2 

1.5 

.35

2 (g/cm /horizon

MgO

.072 

.10 

.13 

.29 

.31 

.55 1 

.15 

.47

.096 

.099 

.19 

.32 

.31 

1.1 1 

.40

.055 

.090 

.21 

.26 

.36 

2.3 2 

1.3 1

.062

.17 

.21 

.18 

.40 

.56 

.11

CaO

.12 

.17 

.15 

.43 

.55 

.2 

.25 

.81

.20 

.18 

.26 

.43 

.55 

.7 

.56

.080 

.13 

.28 

.32 

.52 

.6 

.5

.11

.27 

.29 

.27 

.61 

.88 

.25

in less-than-2

Na2 0

.19 

.36 

.34 

.85 

.93 

2.0 

.41 

1.3

.28 

.33 

.44 

.76 

.98 

3.0 

.85

.11 

.20 

.42 

.50 

.72 

3.2 

2.2

.22

.50 

.48 

.50 

1.0 

1.5 

.47

K20

.16 

.29 

.27 

.70 

.64 

.78 

.19 

.69

.22 

.23 

.33 

.50 

.60 

1.7 

.59

.085 

.15 

.30 

.33 

.44 

1.9 

1.3

.17

.52 

.48 

.38 

.68 

.85 

.31

mm fraction)

Ti02

.023 

.033 

.041 

.092 

.11 

.16 

.034 

.10

.027 

.025 

.049 

.075 

.074 

.27 

.076

.015 

.022 

.053 

.056 

.10 

.44 

.22

.021

.071 

.080 

.061 

.099 

.12 

.035

MnO

.004 

.006 

.007 

.012 

.011 

.025 

.005 

.016

.005 

.005 

.008 

.009 

.011 

.055 

.010

.002 

.004 

.009 

.008 

.016 

.069 

.038

.003

.013 

.012 

.008 

.017 

.021 

.004

Zr02

.001 

.002 

.003 

.006 

.006 

.008 

.002 

.005

.002 

.001 

.003 

.003 

.004 

.012 

.003

.001 

.001 

.002 

.003 

.004 

.019 

.008

.002

.003 

.004 

.003 

.004 

.004 

.002

chrono sequence

.11 

.41 

.69 

.44 

1.4

.039 

.15 

.25 

.15 

.59 1

.067 

.24 

.39 

.25 

.4

.14 

.50 

.83 

.47 

2.9

.095 

.34 

.53 

.33 

1.4

.013 

.046 

.077 

.050 

.13

.002 

.007 

.009 

.006 

.021

.001 

.003 

.006 

.004 

.008

D68 Soil Chronosequences in the Western United States
Supplementary table 7, part 2. Horizon weights of major oxides plus zirconium in the less-than-2- 

mm fraction Continued

No.

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

Age

(ka)

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

120

120

120

120

120

120

120

120

415

415

415

415

415

415

415

415

415

415

415

415

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

600

945

945

945

945

945

Sample

number

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-22

RC-12

RC-12

RC-12

RC-12

RC-12

RC-32

RC-32

RC-32

RC-32

RC-41

RC-41

RC-41

RC-41

RC-41

RC-41

RC-11

RC-11

RC-11

RC-11

RC-11

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-37

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-34

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-35

RC-6

RC-6

RC-6

RC-6

RC-6

Horizon

A

Bit

B2t

2B3t

2Clox

2C2ox

3Cca

3Cn

A

Bit

B2t

2B3t

2Cox

Ap

2B2tca

2B3tca

3Cca

A

Bit

B2t

2B31t

2B32t

2Cox

A

B2t

B3t

2Clca

2C2ca

A

Bit

B2tca

B3tca/K

2Clca

3C2ca

3C3ca

Al

A3

Bit

B2t

2B3t/ca

3Cox/ca

3Clca

3C2ca

A

Bit

B2tca

B3tca

2Clca

2C2ca

2C3ca

2C4ca

A

Bit

B2t

2Clca

2C2ca

Basal horizon i

depth

(cm) S10 2 A1 2 03

5

25

43 

57 

78

175 

197 

+240

9

17

39

62

+ 122

21 

37 7.0 1.6

70

+80

8 4.7 .67

17 6.4 1.0

28 6.9 1.4

51 10. 2.1

65 6.3 1.3

+100 8.6 1.7

9

20 

50

100

+ 180

6

18

45 

63

109

230

+240

8

14

22

37

54

89

160

+210

5

10

18

32

54

135 __

225

+235

13 

30

46

96

+126

2 weight (g/cm /horizon In less-than-2 mm fraction)

Fe ? 0_ MgO CaO Na? 0 ICO TiO. MnO ZrO.

.49 .15 .19 .27 .27 .046 .006 .003

.20 .050 .088 .16 .14 .022 .004 .002

.30 .071 .10 .22 .21 .038 .005 .003

.44 .11 .11 .20 .24 .042 .004 .003

.50 .14 .22 .48 .35 .043 .005 .003

.32 .11 .17 .33 .20 .025 .004 .002

.28 .088 .23 .56 .28 .019 .004 .001

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D69
Supplementary table 7, part 2. Horizon weights of major oxides plus zirconium in the less-than-2- 

mm fraction Continued

2 Basal horizon weight (g/cm /horizon in less-than-2 mm fraction)

No.

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

Age

(ka)

945

945

945

945

945

945

945

945

945

945

945

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

2,000

Sample

number

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-36

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-33

RC-8

RC-8

RC-8

RC-8

RC-8

Horizon

A

Bit

B2tca

B3tca

K

2Clca

3C2ca

3C3ca

3C4ca

4C5ca

4C6ca

Al

A3

Bit

B2t

2B3t/ca

2K1

2K2

3Clca

3C2ca

A

B2t

2B3tca

2K

2Cca

depth

(cm) Si02 A1 2 0 3 Fe 2 °3 M&° Ca° Na2° K2° T1°2

7

16

25 

35

53

80

103

173 

200

227

+255

16

24

43

58

58 

92

180

+220

8

22 

72

112

+ 162

MnO Zr02

Basin chronosequence

154

155

156

157

158

159

160

161

154

155

156

157

158

159

168

169

170

171

172

173

174

175

176

177

178

179

180

7

7

7

7

7

7

7

7

20

20

20

20

20

20

20

20

20

20

20

20

120

120

120

120

120

120

120

RC-46A

RC-46A

RC-46A

RC-46A

RC-46A

RC-46B

RC-46B

RC-46B

RC-20

RC-20

RC-20

RC-20

RC-20

RC-20

RC-43

RC-43

RC-43

RC-43

RC-43

RC-43

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

RC-27

Ap

ACca

2Cgca

2Cox

3Cn

Apca

2Cca

3Cn

A

2Blt

2B2tca

2B3tca

3Clca

3C2ca

A

Bit

B2t

2B3tca

2Clca

3C2ca

A

2Blt

2B2t

2B3ca

3Clca

4C2ca

5C3ca

20 

40

70

98

+ 150

28 26. 4.5 1.4 .70 1.3 .51 .84 .20

60 19. 2.6 .93 .50 1.2 .42 .53 .14

+150 17. 3.0 .79 .33 .69 .68 .53 .092

9 9.9 1.5 .44 .12 .18 .32 .30 .050

15 6.7 1.2 .40 .11 .13 .21 .21 .037

32 11. 2.0 .66 .18 .26 .42 .34 .052

50 11. 1.6 .50 .12 .25 .43 .30 .041

130 27. 3.5 1.1 .26 .70 .98 .67 .085

+330 38. 7.5 1.5 .55 1.2 2.1 1.3 .11

18

33

44 

65

98

+200

6 5.0 .87 .29 .15 .47 .12 .18 .036

11 2.1 .37 .13 .046 .076 .052 .073 .015

19 2.5 .58 .22 .071 .084 .060 .10 .022

34 11. 1.9 .64 .38 2.6 .25 .33 .074

74 39. 6.5 2.1 1.4 5.7 .88 1.2 .27

147 65. 11. 3.5 3.3 7.5 1.8 2.1 .44

+225 20. 3.0 1.1 .55 1.9 .58 .57 .098

.022 .018

.014 .025

.012 .010

.007 .004

.006 .003

.009 .004

.008 .004

.021 .007

.022 .007

.004 .003

.002 .001

.003 .001

.008 .006

.025 .026

.046 .038

.017 .006

D70 Soil Chronosequences in the Western United States
Supplementary table 7, part 2. Horizon weights of major oxides plus zirconium in the less-than-2- 

mm fraction Continued

No. Age 

(ka)

181 

182 

183 

184 

185 

186 

187 

188 

189 

190 

191

192 

193 

194 

195 

196 

197 

198 

199

200 

201 

202 

203 

204 

205 

206 

207

208 

209 

210 

211 

212 

213 

214

215 

216 

217 

218 

219 

220 

221 

222 

223

224 

225 

22.6 

227 

228 

229 

230 

231

415 

415 

415 

415 

415 

415 

415 

415 

415 

415 

415

600 

600 

600 

600 

600 

600 

600 

600

945 

945 

945 

945 

945 

945 

945 

945

945 

945 

945 

945 

945 

945 

945

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000 

2,000

Sample 

number

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23 

RC-23

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24 

RC-24

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25 

RC-25

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44 

RC-44

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A 

RC-26A

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B 

RC-26B

Horizon

A 

Bltca 

B2tca 

B3tca 

2K 

3Clca 

3C2ca 

4C3ca 

5C4ca 

5C5ca 

5C6ca

A 

Bit 

B2tca 

B3tca 

K 

2Clca 

2C2ca 

2C3ca

Aca 

Bltca 

B2tca 

B3tca 

2K 

2Clca 

2C2ca 

3C3ca

Aca 

Bltca 

B21tca 

B22tca 

B31tca 

2B32tca 

2Cca

A 

Bit 

B21t 

B22tca 

B3tca 

2K 

2Clca 

2C2ca 

3C3ca

A 

Bit 

B2tca 

B31tca 

B32tca 

2K 

2Clca 

2C2ca

Basal horizon

depth 

(cm) S102

3 

7 

14 

29 

60 

121 

170 

226 

255 

310 

+320

4 

9 

19 

30 

45 

62 

87 

+300

4 

9 

15 

25 

49 

65 

91 

+ 130

6 

13 

19 

27 

45 

86 

+120

6 

11 

20 

29 

40 

68 

145 

247 

295

5 

10 

16 

25 

36 

48 

88 

+ 170

2.2 

2.4 

2.1 

4.7 

11. 

10. 

9.5 

21. 

7.3

3.3 

4.5 

7.7 

6.0 

3.9 

5.1 

5.8 

54.

2.2

3.6 

4.2 

1.7 

4.1 

3.9 

8.7 

6.1

4.5 

3.0 

8.5 

6.6 

4.5 

6.8 

20. 

46.

5.3

A12°3

.37 

.40 

.39 

.93 

2.0 

2.0 

1.7 

3.9 

1.4

.66 

.92 

1.7 

1.2 

.76 

1.0 

1.1 

9.4

.43

.63 

.84 

.33 

.76 

.77 

1.5 

.94

.71 

.56 

1.6 

1.2 

.84 

1.2 

3.5 

8.0

.99

weight

Fe 203

.11 

.11 

.11 

.21 

.31 

.54 

.39 

.75 

.27

.23 

.32 

.59 

.39 

.23 

.26 

.46 

2.2

.15

.21 

.29 

.11 

.24 

.25 

.49 

.29

.16 

.15 

.43 

.31 

.21 

.23 

.51 

.98

.29

2 (g/cm /horizon

MgO

.038 

.040 

.045 

.11 

.28 

.38 

.31 

.77 

.17

.076 

.11 

.23 

.28 

.34 

.26 

.21 

.83

.090

.083 

.12 

.063 

.33 

.28 

.64 

.37

.050 

.050 

.16 

.13 

.20 

1.0 

1.6 

1.1

.12

CaO

.063 

.074 

.22 

1.8 

4.5 

.81 

.42 

1.9 

.29

.080 

.11 

.29 

1.9 

3.8 

.90 

.26 

1.6

.081

.18 

.31 

.29 

1.3 

2.4 

.98 

.26

.084 

.061 

.17 

.19 

1.6 

5.0 

2.7 

1.7

.14

in less-than-2

Na20

.062 

.074 

.067 

.21 

.54 

.42 

.38 

.97 

.36

.082 

.11 

.18 

.15 

.12 

.22 

.28 

2.7

.088

.085 

.089 

.037 

.11 

.12 

.33 

.21

.15 

.096 

.25 

.22 

.15 

.32 

1.0 

2.5

.15

K20

.081 

.086 

.076 

.15 

.42 

.34 

.28 

.67 

.24

.13 

.17 

.29 

.22 

.13 

.17 

.18 

1.8

.081

.13 

.17 

.064 

.14 

.14 

.29 

.18

.15 

.11 

.33 

.22 

.15 

.25 

.70 

1.5

.20

mm fraction)

Ti02

.014 

.015 

.014 

.026 

.034 

.053 

.038 

.088 

.023

.027 

.036 

.064 

.047 

.029 

.029 

.059 

.25

.018

.025 

.032 

.013 

.030 

.030 

.052 

.029

.024 

.019 

.054 

.041 

.026 

.027 

.065 

.084

.038

MnO

.002 

.002 

.002 

.003 

.004 

.051 

.011 

.012 

.003

.003 

.004 

.007 

.005 

.002 

.003 

.005 

.027

.002

.003 

.003 

.001 

.003 

.003 

.006 

.003

.004 

.002 

.007 

.005 

.003 

.004 

.008 

.012

.003

Zr02

.001 

.001 

.001 

.002 

.003 

.004 

.004 

.007 

.003

.002 

.002 

.004 

.003 

.002 

.002 

.003 

.024

.001

.001 

.002 

.001 

.002 

.001 

.003 

.002

.002 

.001 

.003 

.002 

.002 

.001 

.004 

.006

.003

Soils in Granitic Alluvium along Rock Creek, Carbon County, Montana D71


GPO 785-048/48049