Soils Developed on

s*** ^ I i r-f * I *T" Coastal and Fluvial Terraces 

near Ventura, California

U.S. GEOLOGICAL SURVEY BULLETIN 1590-B

Soils Developed on 

Coastal and Fluvial Terraces 

near Ventura, California

By J.W. HARDEN, A.M. SARNA-WOJCICKI, 

and G.R. DEMBROFF

U.S. GEOLOGICAL SURVEY BULLETIN 1590-B

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 : 1986

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

Harden, Jennifer Willa, 1954-

Soils developed on coastal and fluvial terraces near

Ventura, California.

(Soil chronosequences in the Western United States)

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

Bibliography: p. B17-B18

Supt. of Docs, no.: I 19.3:1590-6

1. Soils California Ventura region. 2. Soil formation 

California Ventura region. 3. Soil chronosequences 

California Ventura region. 4. Geology California 

Ventura region. I. Sarna-Wojcicki, Andrei M. II. Dembroff,

Glenn R. III. Title. IV. Series: Soil chronosequences in the

Western United States. V. Series: United States.

Geological Survey. Bulletin 1590-B.

QE75.B9 no. 1590-B 557.3s 86-600092

[S599.C2] [551.3'55]
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. Machette, 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, 1982; Harden 

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

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 parameters 

for 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 III

Abstract Bl

Introduction Bl

Geographic and climatic setting Bl

Geologic setting B2

Origin and age of geologic units B3

Beach sand underlying the Sea Cliff marine terrace B3

Fluvial deposits in coastal canyons B5

Mixed terrestrial deposits of the Punta Gorda marine

terrace B5

Mixed terrestrial deposits of the Ventura marine terrace B5 

Fluvial deposits derived from the Ventura River B6 

Relation of ages to surfaces and soils B6 

Members of the soil chronosequence B6 

Soil development on the coastal terraces B6 

Amount and mineralogy of clays B7 

Some chemical characteristics of Ventura soils B9 

Total chemical analyses of size separates BIO

Relative rates of element loss from Ventura soils BIO 

Percent loss of elements B13 

Estimating the rates of soil development B13 

Summary and conclusions B15 

References cited B16 

Supplementary tables B19

FIGURES

1. Sketch map of Ventura, Calif., area showing location of study 

area and sampling sites B2

2. Schematic cross section of a marine terrace B3

3. Cross section through the Sea Cliff marine terrace, showing 

scarps of abandoned beaches B4

4. Cross section through the Sea Cliff marine terrace, showing 

locations of samples used for determining C ages and uplift 

rates B4

5-11. Plots of:

5. Percent clay versus basal-horizon depth for four age 

groups of Ventura soils B5

6. Profile sums of clay content versus linear and log age B7

7. X-ray diffractograms of glycolated samples of 

Ventura soils B8

8. Percent silt versus basal-horizon depth for four age 

groups of Ventura soils B8

9. Percent sand versus basal-horizon depth for four age 

groups of Ventura soils B9

10. Organic-carbon content and extractable acidity 

versus linear and log age Bll

11. Total iron oxide content in soil profiles versus linear 

and log age B12

12. Chart comparing relative accumulation of elements in fine (silt 

plus clay) fraction in various horizons B12

13. Plots of net losses of Ca and Mg from the fine (silt plus clay 

fraction versus linear and log age B14

14. Plots of net losses of Fe and Al from the fine (silt plus clay) 

fraction of B horizons versus linear and log age B15

15. Plots comparing soil-development index, percent clay, and total

iron oxide content in Ventura soils with those in Merced soils B16
TABLES

1. Stratigraphic units of the Ventura soil chronosequence B3

2. Estimates of eolian-clay influx into Ventura soils BIO

3. Estimated rates of soil development B17

SUPPLEMENTARY TABLES

1. Field descriptions B20

2. Physical properties B23

3. Extractive chemical analyses B25

4. Mineralogy B26

5. Total chemical analyses of the fine (less than 47 ym) fraction by 

X-ray fluorescence B2 7

6. Total chemical analyses of the less-than-2-mm fraction by X-ray 

fluorescence B29

7. Total chemical analyses of the fine (less than 47 ym) fraction by 

instrumental neutron activation B31

8. Methods used in laboratory analyses B34

VI
SOIL CHRONOSEQUENCES IN THE WESTERN UNITED STATES

Soils Developed on Coastal and Fluvial Terraces 

near Ventura, California

tfyJ.W. Harden, A.M. Sarna-Wojcicki, and G.R. Dembroff

Abstract

We sampled and analyzed soils developing in the 

coastal and fluvial terraces near Ventura, Calif.: (1) 

to test the usefulness of studies of such soils as a 

chronologic tool, (2) to characterize the soils in this 

geologic and climatic setting, (3) to document the 

composition of the soils and long-term rates of soil 

development in this area, and (4) to compare these 

rates with those of soils in other climatic and geomorphic settings. The coastal terraces in the Ventura area 

consist of a marine wave-cut platform overlain by a 

thin veneer of beach sand and gravel, which, in turn, 

are overlain by terrestrial sediment. This area is 

tectonically active, but sampling sites were chosen on 

flat, relatively stable surfaces. Radiometric and 

amino-acid-racemization data on the terrace deposits 

provide maximum ages for the soils. Six terraces, four 

marine and two fluvial, range in age from about 0.5 ka 

to older than about 80 ka. Systematic changes with 

age in many morphologic, physical, and chemical 

characteristics of the soils developed on the terraces 

suggest that the geomorphic surfaces are stable 

enough for soil development to proceed.

Some characteristics of the Ventura soils appear 

to change more rapidly over time than those of soils in 

inland, central California. Clay accumulation is 

especially rapid near Ventura, although the mineralogy 

of the clays does not alter significantly with increasing 

age. This absence of clay-mineral alteration suggests 

that many of the clays are products of mechanical 

weathering, or are inherited from eolian sources or 

colluvial reworking. The rate of accumulation of 

dithionite-extractable iron oxides is faster, and the 

rate of change of the morphologic soil development 

index higher, for Ventura soils than for soils in central 

California.

INTRODUCTION

Marine terraces along the California coast 

provide age control for studies of soil chronosequences 

(in which soils differ in age but have similar climate, 

parent material, vegetation, and slope position). Soil 

development, which is most pronounced on stable or

slowly active landscapes, can be studied on the 

different-age terraces where the surfaces are flat or 

slope gently.

Near Ventura, Calif., the formation of three 

marine terraces was dated previously by radiometric 

and amino-acid methods (Lajoie and others, 1979, 

1982). In addition, two fluvial units have been mapped 

but not accurately dated. The younger of these two 

fluvial deposits is similar in texture and mineralogy to 

deposits in the marine terraces; therefore, the parent 

materials of the soils are similar enough to study as a 

soil chronosequence. The older fluvial unit is composed of coarse gravel of slightly different mineralogy, 

and so this unit is not considered part of the soil 

chronosequence. We studied this unit and the soil 

developed on it, however, for comparison with the 

chronosequence.

The purpose of this study was to examine, 

sample, and analyze soils associated with the marine 

and fluvial terraces near Ventura so as to determine: 

(1) whether the soils developed systematically with 

terrace age, (2) how the soils developed in comparison 

with those other areas, and (3) whether the soils 

developed on marine terraces can be used to identify 

and correlate the terraces near Ventura or elsewhere 

along the coast.

Acknowledgments. Many thanks to Ken Lajoie 

for his generosity with time, ideas, and materials. The 

late D.E. Marchand participated in the planning and 

sampling stages of this study. We thank R.M. Burke 

for early reconnaissance of the study area, and E.M. 

Taylor, C. Terhune, and S. Walker for compiling 

information pertinent to the manuscript. We also 

thank M.C. Reheis and T.K. Rockwell for helpful 

discussions.

GEOGRAPHIC AND CLIMATIC SETTING

Three marine terraces near the town of Ventura 

(fig. 1) were studied by Putnam (1942), Sarna-Wojcicki 

and others (1976), and Lajoie and others (1982). 

Because tectonic deformation is so active in the study 

area, the terraces near Ventura cannot be reliably 

correlated by geomorphic criteria with those west of 

Santa Barbara or with those south of Oxnard. The 

Mediterranean climate of the study area is characterSoils Developed on Coastal and Fluvial Terraces near Ventura, California Bl
119°27'00" 119°17'30"

34°22'00" -

34°17'30" -

Figure 1. Sketch map of Ventura, Calif., area, showing location of study area, sampling sites (dots), and cross 

sections.

ized by a mean annual temperature of about 15° C and 

a mean annual precipitation of about 36 cm. Most of 

the precipitation falls during the cool winters, and the 

xeric soil-moisture regime indicates cycles of effective wetting during winter and desiccation during 

summer seasons. The soil-temperature regime is 

thermic. Vegetation in the study area consists of 

annual grasses and coastal scrub, such as baccharis and 

blackberry.

GEOLOGIC SETTING

The late Cenozoic geology and seismicity in the 

Ventura, Calif., area were studied by Putnam (1942), 

Natland (1952), Palmer (1967), Sarna-Wojcicki and 

others (1976, 1980), Yeats (1977), Lajoie and others 

(1979, 1982), Yerkes and Lee (1979), and Yerkes and 

others (in press). Dembroff (1982), Dembroff and 

others (1982), and Rockwell (1983) studied 

the late Cenozoic geology, neotectonics, 

and soils in the vicinity, concentrating on terraces 

along the Ventura River. Most of the stratigraphy and 

chronology in our study are based on the work of 

Lajoie and others (1979, 1982), although some new data 

and interpretations are included in this report. 

Deposits that constitute the soils' parent materials are 

derived from marine sandstone and conglomerate, 

including, from youngest to oldest, the San Pedro,

Santa Barbara, Pico, Sisquoc, Santa Margarita, Monterey, Rincon, Vaqueros, and Sespe Formations.

Rapid tectonic deformation, in combination with 

eustatic sea-level fluctuations, has created three 

elevated marine terraces that are cut into Cenozoic 

marine rocks. These marine terraces consist of a 

wave-cut platform veneered with fossiliferous marine 

gravel and sand, which, in turn, are overlain by alluvial 

and (or) colluvial sediment containing admixtures of 

eolian material (fig. 2). Fossil mollusk shells in the 

platforms and beach deposits provide information on 

age and climate: first, they indicate the general 

temperature regime that existed during platform 

cutting; and, second, they provide age estimates from 

uranium-series, radiocarbon, and amino-acid-racemization analytical methods. In general, platform 

cutting of these terraces probably occurred during 

relative highstands of sea level later than oxygenisotope stage 5e (approx 120 ka; Lajoie and others, 

1979, 1982). The temperature regime of the shells, 

somewhat cooler than that at present, indicates that 

these terraces are younger than oxygen-isotope stage 

5e. Terrestrial deposits overlie the platforms and 

marine veneers; this terrestrial sediment generally 

constitutes the parent materials of the soils, although 

in some places the soils may have developed below the 

platform on the underlying bedrock sandstone.

In addition to the marine terraces, we also 

studied two sets of fluvial terraces. The younger of

B2 Soil Chronosequences in the Western United States
Soil horizons 

A

Fossiliferous marine sand 

Wave-cut platform

Deformed sediment 

of underlying unit

Qy/s>'"&

Figure 2. Schematic cross section of a marine terrace near Ventura, Calif.

these terraces are situated in small canyons along the 

coast; the older terraces are derived from the Ventura 

River (fig. 1).

Origin and Age of Geologic Units

Soils developed in six units of different ages 

were sampled for this study, but only the youngest four 

units have numerical age control. Each unit and its 

age control are discussed in more detail below. The 

youngest unit consists primarily of beach sand that 

underlies the Sea Cliff marine terrace (geomorphic 

surface) near Pitas Point and Punta Gorda (fig. 1). The 

next unit, referred to as fluvial deposits in coastal 

canyons, consists of mixed fluvial sediment that 

slightly postdates the erosional platform of the Sea 

Cliff marine terrace. The next oldest units, referred 

to as mixed terrestrial deposits of the Punta Gorda and 

Ventura marine terraces, are composed primarily of 

alluvial and (or) colluvial sediment that overlies both 

fossiliferous marine deposits and a wave-cut platform 

(fig. 2) and is of late Pleistocene age. The two oldest 

units of this study are here referred to as fluvial 

deposits of the Ventura River, which are also of late 

Pleistocene age. These oldest units are situated at a 

complex structure in the Ventura Avenue anticline, 

and their ages relative to the marine terraces are not 

well constrained.

Beach Sand Underlying the Sea Cliff Marine Terrace

The youngest unit of this study was sampled in 

two localities (soil samples V2, V7; see table 1). 

Analysis of detailed topographic maps (1:1,200) and 

aerial photographs reveals that the broad geomorphic 

surface (Sea Cliff marine terrace) actually is cornTable 1. Stratigraphic units of the Ventura soil sequence

Parent -material 

deposits

Beach sand 

Fluvial deposits 

Punta Gorda marine

terrace.

Ventura marine terrace ----

Soil 

samples

V2, V7

VI, V6

V4, V5

V8, V9

Age 

control 

(ka)

'0.7

2 - 3 2.5

3 2.55

1 5.6

35(7)

"> 5 40

5 60

120

60

"> 5 85

5 105

Age of

Best estimate 

(ka)

0.7

2

40

80

surface

Conservative 

range (ka)

0.5-0.7

2-5.6

35-60

60-105

Ventura River gravel V3, V10 60-105(7)

'Uplift rate.

2 Uranium-series age.

3l*C age on shells or charcoal.

"*Amino-acid-racemization age or prototheca fossil shells.

5 Cool-water fauna indicate an age younger than 120 ka.

posed of several platforms and shorelines that were 

uplifted and isolated from marine erosion and deposition. Near Pitas Point, nine such shorelines have been 

recognized as scarps that parallel the modern beach 

(figs. 3, 4; K.R. Lajoie, written commun., 1984). 

Maximum ages of the shorelines or beaches can be 

inferred from uplift rates calculated from the elevation of underlying and nearby dated platforms (fig. 4). 

With corrections for the rise in Holocene sea level 

(Bloom and others, 1974), these uplift rates are 5.0 and 

4.2 m/ka. Rates were also calculated for other dated 

localities on the Sea Cliff marine terrace (data not 

shown), and range from about 4.7 to 6.0 m/ka. Because the platforms formed below but near the level of 

the corresponding beach, we assumed that these rates 

also approximate the age of the beach sand overlying 

the platforms. The age of this unit is about 0.5 to 0.7

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B3
METERS FEET 

40-,

-120

30 -

C 20-

10 -

-100

-80

-60

-40

-20

Beach

EXPLANATION

Q Corresponding location of sampling site (located SW. of G'-G)

?) Scarp evident on 1870 map (1:10,000 scale) and 

1947 airphotos (1:24,000 scale)

Scarp evident on 1962 map (1:1,200 scale)

N. 39° W

Back edge of Sea Cliff 

marine terrace

25 50 METERS

VERTICAL EXAGGERATION X5

Figure 3. Cross section G-G1 through the Sea Cliff marine terrace, showing scarps of abandoned beaches (see 

fig. 1 for location).

METERS FEET 

40-i

-120

30-

O

aO)

^ 20 H

z 

O

5E

10-

- 100

EXPLANATION

\J Corresponding location of sampling site 

-n P v Wave-cut platform

N.15°W.

-60

H40

-20

' """\andfill

C 14 age on shell 

(sample number)

<17.1 m/3.8 ka=4.5 m/ka

<10m/2.6ka=3.8m/ka

Beach

Back edge of Sea Cliff 

marine terrace

(5.0)

- (4.2)

25 50 METERS

VERTICAL EXAGGERATION X5

Figure 4. Cross section H-H1 of the Sea Cliff marine terrace, showing locations of samples used for determining C ages and uplift rates (see fig. 1 for location). Indian midden is directly across stream from soil profile V6.

B4 Soil Chronosequences in the Western United States
ka, on the basis of uplift rates measured at scarps 8 

and 9 in figure 3 at an elevation of 3 to 4 m. Sample 

V7 might be slightly younger than V2 on the basis of 

scarp elevation, but we assumed that the sampling 

sites are too close together to differentiate the 

overlying dune sand.

Fluvial Deposits in Coastal Canyons

Two fluvial terraces, both about 2 ka old, 

postdate the platform of the Sea Cliff marine terrace. 

These terraces here are considered as one unit, labeled 

"fluvial deposits" in table 1.

Site V6 is located across the canyon from a 

stream terrace at a similar elevation that is overlain 

by an Indian midden site (fig. 4), from which shells 

were collected and 14C-dated at 2.55 ka1 . The age of 

the wave-cut platform at this locality is about 4.2 to 

5.6 ka, on the basis of maximum and minimum uplift 

rates (fig. 4). The surface and soil, then, are probably 

about 2 to 2.5 ka old and no older than about 5.6 ka.

Site VI is located on a fluvial terrace along 

Padre Juan Canyon (fig. 1). The apparent absence of 

buried soils within the upper 3 m of the surface 

suggests no significant hiatuses in deposition. In Javon 

Canyon to the northwest is a similar, prominent 

stream terrace that probably is correlative with the 

terrace in Padre Juan Canyon, on the basis of its 

elevation above the streams. Charcoal from the 

terrace m Padre Juan Canyon at a depth of about 1.5 

m was 14C-dated at 2.365±0.065 ka (sample Beta1085). Sampling sites VI and V6 were combined to 

represent a single time-stratigraphic unit that dates 

from 2 to 5.6 ka.

Mixed Terrestrial Deposits of the Punta Gorda Marine 

Terrace

The next oldest unit is associated with the Punta 

Gorda marine terrace (fig. 1; Lajoie and others, 1982), 

which includes a wave-cut platform overlain by 

terrestrial deposits (fig. 2). This platform was cut 

from about 60 to 40 ka, on the basis of the cold-water 

aspect of molluscan fauna, uranium-series ages, and 

amino-acid data on fossil shells found at the contact 

between the marine and terrestrial units (table 1; 

Lajoie and others, 1979). Given the limitation of 

uranium-series and amino-acid dating techniques, the 

platform could be from 35 to 60 ka old, corresponding 

to relative sea-level highstands (Bloom and others, 

1974) during which the platforms could have been cut.

The age of terrestrial deposits of the Punta 

Gorda marine terrace has not been determined directly. If sedimentation processes are similar on the Punta 

Gorda and Sea Cliff marine terraces (see next subsection), the sediment probably postdates platform

Shells from the midden were discovered in a 

plowed field, and so these shells could have come from 

just below the surface.

cutting by about 3 ka. If sedimentation was continuous 

since platform erosion, or if sedimentation rates were 

relatively low in comparison with those on the Sea 

Cliff marine terrace, the sediment and surface of the 

Punta Gorda marine terrace could be significantly 

younger than the platform. This is unlikely, however, 

because (1) the Punta Gorda marine terrace lies north 

of the axis of the Rincon anticline, and so tilting has 

been toward the north, away from the distal edge of 

the terrace; and (2) stream incision probably followed 

shortly after uplift. Fluctuation of the clay content of 

the sediment with depth (fig. 5) indicates cycles of 

clay and silt deposition and, possibly, pulses of sedimentation. Although we assigned an approximate age 

of 40 ka to the surface and soil of the Punta Gorda 

marine terrace, this terrace could be from 35 to 60 ka 

old.

Mixed Terrestrial Deposits of the Ventura Marine 

Terrace

The geomorphic surface referred to by Lajoie 

and others (1982) as the Ventura terrace is older than 

the Punta Gorda marine terrace but occurs at lower 

elevations than the Punta Gorda marine terrace 

because of its relative position on the southern limb of 

the Ventura Avenue anticline (fig. 1; Lajoie and others, 

1982, p. 46). The Ventura marine terrace is cut into 

older, deformed bedrock. Amino-acid-racemization 

analyses of fossil mollusks yield estimates of 85 to 105 

ka for the age of the platform (fig. 2). These sheUs 

also indicate cooler water conditions in comparison

ou

40

30

20

10

0

i i i i 

A

-

- ^s^>

-

"l 1 1 1

B

CJ 50 

I 40

T T 1

D

0 100 200 300 400 0 100 200 300 400 

BASAL-HORIZON DEPTH, IN CENTIMETERS

Figure 5. Percent clay versus basal-horizon depth for 

four age groups of Ventura soils. A, Soils in post-Sea 

Cliff marine terrace (approx 2 ka). B, Soils in Punta 

Gorda marine terrace (approx 40 ka). C, Soils in 

Ventura marine terrace (approx 80 ka). Dj Soils in 

Ventura River gravel (approx 80 ka). Numbers denote 

profiles (see supp. table 2).

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B5
with the present and with oxygen-isotope stage 5e; 

thus, the shells and platform are less than about 120 ka 

old.

Fossil marine shells that were found at about 3- 

m depth in both soil pits in the Ventura marine terrace, directly on top of the marine platform, indicate 

the approximate depth of the platform. The thickness 

of terrestrial sediment is about the same as on the Sea 

Cliff marine terrace, and sedimentation and subsequent surface stabilization apparently occurred soon 

after platform erosion. An approximate age of 80 ka 

was assigned to this surface and soil, but the unit could 

be as old as about 105 ka; a constraining minimum age 

is more difficult to assess. Modern analogs of terrace 

formation, rapid tectonic uplift, and rapid incision 

rates that isolate terraces from stream deposition, and 

the fact that we sampled away from colluviated 

slopes, led us to assume that the surface age is within 

a few thousand years of the platform age.

Fluvial Deposits Derived from the Ventura River

In addition to soils developed on marine terraces, 

we examined soils developed in stream gravel from the 

Ventura River. Two stream terraces west of the river 

(fig. 1) are the highest (150-200 m) and, thus, possibly 

the oldest Ventura River terraces at the coast. The 

deposits are composed of coarse gravel containing 

rounded clasts reworked from Tertiary sedimentary 

rocks to the north. The surfaces and bedrock platform 

dip about 9°-15° S., about the same as the Ventura 

marine terrace and platform to the east. These dips 

are too steep to be original fluvial-terrace gradients, 

and so the deposits must have been tilted by folding on 

the Ventura Avenue anticline. The similar tilts on the 

river-terrace and marine-terrace platforms suggest 

that the units were formed approximately coevally. 

We assign an age of about 80 to 105 ka to the two river 

terraces and their soils.

Because these soils have much coarser parent 

materials, they are not part of the soil chronosequence 

that includes the younger units of this study. Some 

interesting comparisons, however, can be made 

between soils on the Ventura marine terrace and soils 

on the Ventura River gravel.

Relation of Ages to Surfaces and Soils

Specific ages of surfaces and soils are assigned 

to the geologic units of this study (figs. 5-8; table 1) to 

demonstrate the age trends of soils. Some of the ages 

of these units are only tentative and, as is apparent 

from the preceding discussion, of varying reliability. 

The text figures demonstrate graphically the uncertainties in age assignments that are outlined above.

Most of the ages in this study provide maximum 

ages for the landform surface and, thus, for the soil; 

however, minimum ages are not well constrained. 

Most of the ages are for materials 2 to 4 m below the 

landform surface (for example, shells from the marine 

platform; see fig. 2). The uncertainties in these ages, 

listed in table 1, account for as much as a 20-ka error, 

which might be possible if age calibration for uraniumseries or amino-acid analyses was off by one entire 

interstadial. A more difficult question pertains to a 

mimimum age for the surface and soil; that is, how 

long did it take (1) for the upper 2 to 4 m of sediment 

to accumulate and (2) for sedimentation to cease so 

that soil development could commence? As discussed 

above, several lines of evidence suggest that sedimentation of these deposits and subsequent abandonment 

of the surfaces were relatively rapid. First, the nearmodern analog of a marine terrace is the Sea Cliff 

marine terrace, the surface of which is 0.5 to 0.7 ka 

old at its front edge and about 2.5 ka old at its back 

edge. The terrestrial sediment is composed of beach 

sand and (or) fluvial deposits and is about 2 to 3 m 

thick. Second, stream incision has begun and is 

significant at the backedge, features suggesting that 

the backedge of the terrace is no longer accumulating 

material and has stabilized. Our estimate of the date 

for surface stabilization of the Punta Gorda and 

Ventura marine terraces is 3 ka to no earlier than 5 

ka. Rapid stabilization is also suggested by the 

absence of buried soils that would indicate hiatuses, by 

the similarity in the thicknesses of terrestrial sediment within the Sea Cliff and Ventura marine terraces, and by similar slopes of the platforms and 

terrace surfaces. The two most significant uncertainties in regard to the terrestrial deposits are colluvialsediment and eolian-dust additions, which are discussed in the next section.

Members of the Soil Chronosequence

The soil chronosequence of this study is composed of four different-age soils that are developed in 

various types of deposits: (1) beach sand that overlies 

the platform of the Sea Cliff marine terrace, (2) 

fluvial deposits that slightly postdate the platform of 

the Sea Cliff marine terrace, (3) terrestrial deposits 

that overlie the platform of the Punta Gorda marine 

terrace, and (4) terrestrial deposits that overlie the 

Ventura marine terrace. All of these deposits appear 

to have been composed primarily of sand and silt 

before the onset of soil formation and eolian-dust 

accumulation. Therefore, these deposits and their 

soils are here considered as members of a soil chronosequence, in which parent material, climate, vegetation, and slope position are comparable but the 

duration or time of soil development differs.

Soils developed in the Ventura River gravel are 

not considered to be members of this chronosequence, 

however, because the parent materials are composed 

primarily of gravel, which differs significantly from 

the finer grained deposits of other units. Nonetheless, 

some interesting comparisons can be made between 

these soils and those of the marine terraces.

SOIL DEVELOPMENT ON THE COASTAL TERRACES

Soils of this study range from minimally developed Entisols that lack any diagnostic soil horizons to 

well-developed Mollisols that have thick, dark A 

horizons enveloping or "tonguing into" the underlying

B6 Soil Chronosequences in the Western United States
200

150

100

50

200

150

100

50

120

100

80

60

40

20

0

20 40 60 80 100 

AGE, IN THOUSANDS OF YEARS

120

10 2 10 4 106 10 8 

AGE, IN YEARS

101 101

Q <

LLJ Z)

I- O

o °-

O CO

80 

60 

40 

20 

0 -

20 40 60 80 100 

AGE, IN THOUSANDS OF YEARS

120

D

10 b 10 B 

AGE, IN YEARS

10 1 10'

Figure 6. Profile sums of clay content versus linear (A, B) and log (C, D) age. Percent clay was multiplied by 

horizon thickness (in centimeters) and bulk density (in grams per cubic centimeter), and the products were 

summed for each profile (A, C); to correct for parent material, minimum percent clay content in profile was 

subtracted before multiplying by horizon thickness (B, D). Horizontal lines, age uncertainty; dots, best-estimate 

ages of soils on coastal terraces; circled dots, soils developed in Ventura River gravel (table 1). Solid lines (A-D) 

approximate trends of data; dashed lines (A, B) indicate trend if linear rates are assumed.

argillic horizons. The dark colors, found as deep as 

about 1.5 m, appear to be those of clay and silt 

associated with organic carbon. The salts of the sea 

spray probably play an important role in dispersing 

organic matter into a mobile form, as well as in 

binding the organic compounds into clay and silt, 

resulting in a dark complex of organic material and 

clay.

The influence of sea spray on the rate and type 

of soil development was discussed by Yaalon and 

Lomas (1970) and Kingston and Gailitis (1976). More 

recently, in the Ventura area, Dembroff and others 

(1982) and Rockwell (1983) proposed that soil-development rates are accelerated in part by the sodium 

influence on clays. Harden and Taylor (1983), however, concluded that many aspects of soil development 

were not profoundly affected by salt spray, because 

similar-age soils of this study and of the Central 

Valley of California are morphologically similar. One 

objective of this more detailed study of the Ventura 

soils was to characterize the physical, chemical, and 

mineralogic aspects of soil development and to 

determine whether the development rates of these 

properties are significantly affected by the coastal 

salt spray.

Amount and Mineralogy of Clays

To evaluate and compare soil development, 

patterns and characteristics of the parent materials 

must be identified and separated from pedogenic 

features. Deposits associated with the young Sea Cliff 

marine terrace contain about 18 to 20 percent clay 

(see supp. tables 2, 8), relatively uniformly distributed 

with depth, at least to about 2 m (fig. 5A). Older 

marine-terrace units (Punta Gorda and Ventura), which 

appear to be stratified with respect to particle size, 

generally contain about 20 percent clay in A and C 

horizons, values suggesting that the higher clay 

content in B horizons is pedogenic and (or) eolian (figs. 

5B, 5C_). A and C horizons of the soils in Ventura 

River gravel (fig. 5D) contain about 10 percent clay 

and are much less stratified than the marine-terrace 

soils.

The stratification of the Punta Gorda and 

Ventura sediment suggests that not all of the Bhorizon clay may be pedogenic, although determination 

of the original clay content is nearly impossible. If the 

volume of clay in each soil profile is simply calculated, 

clay content increases significantly with age for the 

chronosequence soils (figs. 6_A, 6C), but the fluvial

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B7
16.5

13°

26

Figure 7. X-ray diffractograms of glycolated samples 

from four Ventura soils. Numbers are angstrom spacings above peaks of kaolinite (K), mica-illite (M), and 

smectite (S) for each sample. Values in parentheses 

are ages of soils (see table 1).

units contain less clay than soils in the oldest marine 

terrace (Ventura). This difference suggests that 

parent material and, more specifically, rock type and 

original grain size influence to some extent the 

content of pedogenic clay. In comparison with the 

clay content of Merced soils in central California 

(Harden, in press), Ventura soils of the main terraces 

contain much more clay for similar-age soils. For 

example, the 80-ka-old Ventura soils contain about 150 

g clay/cm , whereas the 130-karold Merced soils 

contain about 90 to 100 g clay /cm . To compensate 

for some of the original clay content among these 

soils, we subtracted the minimum clay content within 

each profile from the percent clay of each soil horizon 

(figs. 6B, 6D). This simplified correction for parent 

material appears to smooth the time curve or reduce 

the variation in scatter diagrams, but the Ventura soils 

still contain more clay than the Merced soils. For 

example, the 80-ka-old soils now contain 70 to 90 g 

clay/cm (fig. 6), whereas the 110-ka-old Merced soils 

contain about 40 to 50 g clay/cm (Harden, in press).

Although the rates of clay accumulation are 

higher in the Ventura than in the Merced area, there is 

little mineralogic evidence for inplace clay formation 

or alteration. Diffractograms of B-horizon clay (see 

supp. table 8) show virtually no change in the peak 

heights of different clay types throughout the age 

range of the marine terraces (fig. 7). The clays of all

50

40

30

20

10

E 50

3. D

100 200 300 400 0 100 200 300 

BASAL-HORIZON DEPTH, IN CENTIMETERS

400

Figure 8. Percent silt versus basal-horizon depth for 

four age groups of Ventura soils. A, Soils in post-Sea 

Cliff marine terrace (approx 2 ka). B> Soils in Punta 

Gorda marine terrace (approx 40 ka). Cj Soils in 

Ventura marine terrace (approx 80 ka). _D, Soils in 

Ventura River gravel (approx 80 ka). Numbers denote 

profiles (see supp. table 2).

the marine-terrace soils consist predominantly of 

smectites, with smaller amounts of mica or illite and 

kaolinite. Local sources for alluvial and colluvial 

parent materials are also dominated by these clays 

(Quaide, 1957; Kerr and others, 1971). The similarity 

in amounts and types of clay minerals in the differentage soils suggests that the clays either are formed 

from coarser particles of similar mineralogy or are 

depositional (rather than pedogenic) and from a 

consistent source.

Mechanical breakdown of silt and sand may be 

one source of B-horizon clays in the Ventura soils. If 

coarser particles were of similar mineralogy, disaggregation or physical breakdown without chemical 

weathering might account for the observed increase 

in clay content and the absence of clay-mineral 

transformation. In figure 8, the depth functions of silt 

appear nearly identical to those of clay (fig. 5); 

increases and decreases of both size fractions with 

depth occur in similar horizons. The parallelism and 

covariance of the silt and clay fractions suggest that 

these particles were deposited in similar sedimentologic regimes; it also suggests, but does not prove, that 

significant amounts of pedogenic clay are not forming 

by breakdown of silt particles. Formation of clay and

B8 Soil Chronosequences in the Western United States
silt from weathering sand grains might have occurred, 

as suggested by inverse relation of the general depth 

trends of silt and clay to that of sand (fig. 9). Alternatively, this proportionality may represent depositional changes between sand-rich and silt- and clayrich material, or influx of eolian silt and clay with 

corresponding decrease (dilution) of sand. A slight 

decrease of silt/clay ratios (fig. 8C_) in B horizons 

suggests that the clays, if a product of mechanical 

breakdown, are just as likely formed from sand- as 

from silt-size particles.

One probable origin of B-horizon clays is eolian 

deposition. Muhs (1980, 1982) studied a series of 

marine terraces on San Clemente Island to the south of 

the town of Ventura (fig. 1) and concluded that large 

volumes of silt and clay had been deposited onto the 

terraces by Santa Ana winds (a common meteorologic 

condition due to formation of high-pressure areas to 

the east of southwestern California, and of any 

easterly winds that transport material form those 

areas to the west). The mineralogy of clays in Muhs1 

dust traps and soils consisted of kaolinite, mica or 

altered mica, and smectite, as well as feldspar and 

quartz. Muhs (1980, p. 91) calculated an average 

annual rate of eolian deposition during a timespan of 

about 3 ka, although he believed that most of the 

sediment was generated historically during immigration and settlement. For the Ventura soils of this 

study, we subtracted the annual volume of eolian clay 

reported by Muhs from the pedogenic volume of clay

80

60

40

20

$ 8°

E

I 6° 

A

40

20

B

D

100 200 300 400 0 100 200 300 

BASAL-HORIZON DEPTH, IN CENTIMETERS

400

Figure 9. Percent sand versus basal-horizon depth for 

four age groups of Ventura soils. A, Soils in post-Sea 

Cliff marine terrace (approx 2 ka). B, Soils in Punta 

Gorda marine terrace (approx 40 ka). C, Soils in 

Ventura marine terrace (approx 80 ka). D, Soils in 

Ventura River gravel (approx 80 ka). Numbers denote 

profiles (see supp. table 2).

(corrected for parent material). The remaining clay 

might provide a minimum estimate of the clay formed 

in place in Ventura soils, separately from eolian clay 

added to the soils. Assuming that eolian deposition 

was continuous over time throughout the 80-ka age 

range of the soils (table 2), net clay formed in place is 

generally lower in Ventura than in Merced soils. 

Assuming that deposition of eolian clay took place 

within the past 3 ka (Muhs, 1980, p. 91), then the clay 

volume of Ventura soils is about the same as that of 

Merced soils except for soils on the 80-ka-old Ventura 

terrace, which still contains more clay (table 2).

One argument against an exclusively eolian 

source for the clays is that the soils on Ventura River 

gravel do not contain a significant amount of clay in 

comparison with soils of similar age near Merced. In 

other words, if excessive amounts of clay were due 

only to eolian input in Ventura soils, then profiles on 

the fluvial gravel would also have very high clay 

contents, which is not the case (fig. 6). This observation is inconsistent, however, because Dembroff and 

others (1982) and Rockwell (1983) demonstrated rapid 

rates of clay accumulation in gravelly terraces of the 

Ventura River upstream from the study area.

Another source for clay in the Ventura soils is 

local slopewash. Local slopes contain the same clay 

minerals as the soils and eolian dust, and so it is 

difficult to distinguish slopewash from materials of 

eolian and pedogenic origins. Although accretion rates 

of eolian clays may account for the high clay content 

of these soils, the soils undoubtedly have inherited 

some clay from upslope as well.

Some Chemical Characteristics of Ventura Soils

Several chemical characteristics of Ventura soils 

change progressively as a function of estimated soil 

(surface) age, despite the absence of clay-mineral 

alteration discussed earlier. Furthermore, Harden and 

Taylor (1983) demonstrated highly systematic changes 

in morphology of these soils with age, indicating that 

the coastal terraces are stable enougn to develop soils, 

at least for the slope positions and age ranges of 

deposits examined in this study. Chemical characteristics that change most systematically with age 

include organic-carbon content (very young soils only; 

see supp. tables 3, 8), total acidity, dithionite-extractable iron (see tables 3, 8), and total Ca, Mg, and Fe of 

fine size fractions (silt plus clay or less than 47 ym; see 

supp. tables 6, 8).

Organic-carbon content of these Ventura soils, 

expressed as the total volume of carbon in the soil (fig. 

10), increases significantly in about the first 2 ka; by 

about 40 ka, the carbon content has declined and 

apparently reaches a steady state or begins to decrease (figs. 10A, 10C_). The change from accumulation to loss of soil carbon occurs sometime between 

about 2 and 40 ka in Ventura soils. This pattern of 

accumulation and attrition is documented in other 

studies that have chronosequences ranging from the 

Holocene through pre-Holocene, and the change to 

carbon attrition generally occurs in the middle to early 

Holocene (Jenny, 1979; Harden, in press). In soil 

chronosequences that demonstrate a significant

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B9
Table 2. Estimates of eolian-clay influx into Ventura soils

[Estimates based on data of Muhs (1981) for dust trap 3 at 31 (g soil/m2 )/yr, or O.SlxlO' 3 (g clay/m2 )/ 

yr. Maximum and minimum estimates for eolian clay are based on maximum and minimum ages, respectively, 

of Ventura units. Merced data from Harden (in press)]

Sample

Approx. 

mi ni mum 

age 

(ka)

Maximum 

age 

(ka)

Clay gained, 

corrected 

for parent 

material 

(g/cm2 )

Eolian clay 

(estimated) 

(9/cm2 ) 

(max) (min)

Net clay formed 

(g/cm2 ) 

(max) (min)

Merced 

clay 

(g/cm3 )

Estimated 

age 

(ka)

Assuming that eolian deposition occurred continuously for 105 ka

V2 0.7 2.5 3.02 0.57 2.03 2.45

VI 

V6

V4 

V5

V8 

V9

2.5 

2.5

35 

35

60 

60

5.6 

5.6

60 

60

105 

105

4.35 

7.65

39.60 

9.44

71.50 

93.70

2.03 

2.03

28.35 

28.35

48.6 

48.6

4.54 

4.54

48.60 

48.60

85.05 

85.05

2.32 

5.62

11.25 

-18.91

22.90 

45.10

-.10 

3.11

-9.0 

-39.16

-13.55 

8.65

5.3

25.6

48.14

3

40

130

Assuming that eolian deposition occurred within the past 3 ka

V2 0.7 2.5 3.02 0.57 2.03 2.45 0.99

VI

V6

V4

V5

V8

V9

2.5

2.5

35

35

60

60

5

5

60

35

105

105

4.35

7.65

39.60

9.44

71.50

93.70

2.03

2.03

2.43

2.43

2.43

2.43

2.43

2.43

2.43

2.43

2.43

2.43

2.32

5.62

37.17

7.01

69.07

91.27

1.92

5.22

37.17

7.01

69.07

91.27

5.3

_

25.6

_

48.14

 

 

__

 

increase followed by a decline in soil organic-matter 

content, soil fertility may increase in the early stages 

of soil development. At some later stage, a key 

nutrient(s) or property may then become limiting, 

causing a decline in the vegetative input to soil 

organic matter. In Ventura soils, accumulation 

ceases at or after about 2 ka, but soil carbon does not 

decline significantly in older soils. Carbon retention 

and (or) soil fertility apparently are maintained for 

more than 80 ka after the organic matter is established.

Total acidity (extractable hydrogen) increases 

with age in the Ventura soils, although variation within 

age groups is significant in older soils (figs. 10B, 

10D). This increase in acidity suggests that leaching 

of basic cations is effective in these soils, despite the 

high clay content and salt influx from the ocean.

Increase in dithionite-extractable-iron content 

with age may indicate recrystallization of Fe from 

primary minerals into oxide forms, recrystallization of 

other iron oxides, and (or) influx of iron oxides from 

eolian or other sources. Dithionite-extractable-iron 

content (Mehra and Jackson, 1960) increases highly 

systematically with age, and soils developed in Ventura 

River gravel contain considerably more Fe than soils 

of similar age on the Ventura marine terrace (fig. 

11A).

L Alternatively, the decline in soil carbon content 

could be related to decomposition, although most 

studies do not demonstrate a significant change in C/N 

ratio at the time of the decline.

Total Chemical Analyses of Size Separates

Total chemical analysis of size separates demonstrates the relative concentration of elements and, 

thus, the chemical differentiation that has occurred in 

soils of this study. The fine (less than 47 vim) fraction 

of selected horizons was separated after sonic dispersal (Busacca and others, 1984b) and wet sieving, then 

analyzed by X-ray fluorescence (see supp. table 3). 

Two methods were used to examine chemical differentiation over time: the accumulation-series method 

(Harden, in press), in which relative gains and losses 

are compared by using elemental ratios and relative 

ages; and the percent-loss method, which calculates 

the loss of elements relative to a stable species and a 

standard (Merrill, 1921).

Relative Rates of Element Loss from Ventura Soils

In the accumulation series methods, described in 

more detail by Harden (in press), we (1) calculate a 

ratio of the concentration of each element to that of 

every other element, (2) rank each ratio from smallest 

to largest, (3) rank the ages of soils from young to old, 

and (4) perform linear regression on ranked ratio 

versus ranked age. If the correlation coefficient 

(Spearman's rho) is significant for a positive slope, for 

example, then the element in the numerator is accumulating more rapidly than that in the denominator. 

Each elemental ratio is tallied into a series. Relative 

accumulation could be a result of either net gain or 

concentration relative to the loss of other elements;

BIO Soil Chronosequences in the Western United States
3.5

2.8

2.1

1.4

O CO 07 U -'

2.8

2.1

1.4

0.7

0 -

10 2

20 40 60 80

AGE, IN THOUSANDS OF YEARS

100 120

104 106 10 8 

AGE, IN YEARS

10 10 10 1

20.0

16.0

12.0

8.0

4.0

0 -

< 

o

3 20.0

^ 16.0

20 40 60 80

AGE, IN THOUSANDS OF YEARS

100 120

12.0

8.0

4.0

D

©-

o -, -L

10 2 10 6 10 8 

AGE, IN YEARS

10 10 101

Figure 10. Organic-carbon content (A, C) and extractable acidity (B> JD) versus linear (A, B) and log (Cj D) age. 

Percent carbon or milliequivalents of hydrogen were multiplied by horizon thickness (in centimeters) and bulk 

density (in grams per cubic centimeter), and the products were summed for each profile. Horizontal lines, age 

uncertainty; dots, best-estimate age of soils on coastal terraces; circled dots, soils developed in Ventura River 

gravel (see table 1). Solid lines approximate trends of data; dashed lines indicate trends if linear rates are 

assumed.

relative depletion could be a result of either actual 

loss or dilution by other incoming species.

There are several advantages to the accumulation-series method over the percent-loss method. 

First, because each element is examined relative to 

several other elements, fortuitous correlations of 

elements that are unrelated to time are generally 

recognized. Likewise, extreme variation in the 

content of an element is also recognized. Second, 

associations of elements in some cases related to 

weathering and in other cases to mineralogy or 

deposition are recognized as groups whose ratios do 

or do not correlate over time. Third, the regression is 

based on ranked or relative ages rather than absolute 

ages, and so uncertainties associated with absolute age 

are not of concern. Fourth, curve fitting (for example, 

by polynomial or exponential functions) is unnecessary 

because the axes are ranked.

For the fine (less than 47 ym) fraction of soils 

developed on marine terraces , relative accumulations 

of elements are best defined in A horizons (fig. 12). 

The alkaline-earth elements Mg and Ca are lost most 

readily and (or) are being diluted by the net increase of 

other elements listed to their left in figure 12. 

Phosphorus is also lost or diluted relative to everything 

but Ca and Mg. Fe and Mn are intermediate in the 

series and could be either depleted or stable relative 

to Si, Al, K, and Na. Relative to soils near Merced, in

o

°The two soils developed in Ventura River gravel 

were omitted because of their dissimilarity of parent 

material and because their ages relative to the oldest 

marine terrace and to each other are somewhat 

tenuous.

Soils Developed on Coastal and Fluvial Terraces near Ventura, California Bll
10.0

8.0

6.0

4.0

2.0

0 -

20 40 60 80 100 120 

AGE, IN THOUSANDS OF YEARS

8.0

6.0

4.0

2.0

0 -

B

10 6 10 8 

AGE, IN YEARS

10 1 101

Figure 11. Total iron oxide content in soil profiles 

versus linear (A) and log (B) age. Dithionite-extractable-iron content (in percent) was multiplied by 

horizon thickness (in centimeters) and bulk density (in 

grams per cubic centimeter), and the products were 

summed for each profile. Horizontal lines, age uncertainty; dots, best-estimate age of soils on coastal 

terraces; circled dots, soils developed in Ventura River 

gravel (see table 1). Solid lines approximate 

trends of data; dashed lines indicate trend if linear 

rates are assumed.

both studies Si is retained relative to Al Na Mg Ca. In 

Merced soils, Fe accumulates more rapidly than Si, K, 

Al, and Mg, whereas in Ventura soils, Fe is depleted or 

diluted relative to these four elements. In Ventura 

soils, either there is a net influx of Si, K, Al, and Na, 

or Fe is depleted from this size fraction. If Zr is 

stable and immobile (Wild, 1961; Barshad, 1964; 

Busacca, 1982; Harden, in press), then at least some Fe 

is lost from the fine fraction of A horizons, as are Mn, 

Mg, and Ca. Alternatively, if some Zr is blowing in, 

then Fe may be staDle or may be blowing in more 

slowly than Zr. Chemical analyses of airborne dust 

would help to answer this question.

Trends of elemental ratios over time are less 

well defined in B and C horizons (fig. 12). In the fine

Relative 

accumulation

A horizons

B horizons

C horizons

Relative depletion 

or dilution

-Zr, TiSi>AI>Na>Fe, Mn>Mg>Ca 

I P I

Hvlg.Na, KH 

Si, Fe, AI>Zr>Ca 

Ti Mn

Na>Si

Comments:

Influx of Si ? 

depletion of 

Mg, Ca, P

Influx of Si, Al, 

Fe; depletion of 

Ca; retention of 

Mg, Na ?

Influx of Na ?

Figure 12. Relative accumulation of elements in fine 

(silt plus clay) fraction of A, B, and C horizons. 

Elemental ratios (see supp. table 6) are ranked and 

correlated with relative age; significant increases/decreases with age are incorporated into accumulation 

series shown. A series is indicated by elements in a 

line; elements outside of a series do not show significant gain or loss relative to other elements within the 

same series. Samples exclude soils in Ventura River 

gravel (see table 1).

fraction of B horizons, Ventura soils accumulate Si, 

Fe, and Al and lose Ca relative to Zr; most other 

elemental ratios do not change significantly over 

time. As measured in A horizons, Ca is depleted 

relative to Zr. In contrast to A horizons, there is a net 

influx of Fe (relative to Zr) into the fine fraction of B 

horizons. In BC or C horizons, the only significant 

trend is an increase of Na relative to Si. In A horizons, Si increases relative to Na, and so Na may be 

leached into C horizons from overlying strata. 

(Alternatively, A horizons may receive Si from eolian 

sources.) The absence of significant trends over time 

in C horizons is probably due to both the varying depth 

of C horizons (see supp. table i) and the absence or 

variation of pedogenic processes at these depths.

Despite the ambiguity of some elemental trends 

over time, there are some general patterns in the total 

chemistry that may be the result of soil formation. In 

A horizons, the composition of the fine fraction 

appears to be dominated by leaching of the alkalineearth elements. Zr does not increase relative to any 

other element, and so without certain evidence for the 

stability of other elements (such as Fe), we cannot 

conclude that there is a net gain of any element. Most 

likely, however, on the basis of the volume of clay that 

appears to be accumulating in these soils, there is a 

net gain of not only Si, Al, Na, and K but also Zr and 

Ti. Analysis of slopewash and eolian materials might 

help to resolve this question. In B horizons, the net 

increase of Si, Fe, and Al is probably the result of clay 

formation and (or) translocation. Ca is lost at a 

significant rate, as evidenced by its depletion relative 

to all other elements. The apparent retention of Mg 

could be due to the presence (and possibly the influx) 

of smectite.

Both similiarities and differences exist between 

the trends in Ventura and Merced soils; further study 

of these soils may resolve the question of eolian 

influence and the effect of slopewash. Similarities in

B12 Soil Chronosequences in the Western United States
the analysis of Merced soils (Harden, in press) include 

the loss of several elements from A horizons relative 

to Zr, the loss of only the alkaline-earth elements 

from B-horizon fines, and the apparent gain of Fe, Al, 

Ti, and, possibly, Si into B-horizon fines. In contrast 

to Ventura soils, Merced soils show a significant loss of 

Mg in B horizons (although Mg is lost more slowly than 

Ca, whereas the reverse is true in A horizons). There 

is no evidence for the formation of smectite or 

vermiculite in Merced soils, and so the retention of Mg 

in Ventura clays may, indeed, be related to the 

formation or influx of these clay types. Also in 

contrast to Ventura soils, Merced soils retain Fe in the 

fine fraction of A horizons. This difference might be a 

clue to eolian sources or to differences in Fe transformations.

Percent Loss of Elements

The relative accumulation of elements helps to 

decipher chemical differentiation, but using units for 

net loss and gain of constituents has the advantage of 

comparability to other size fractions, horizons, and 

soils from other areas. Zr is probably the best candidate for a stable or resistant element, on the basis of 

several studies (Wild, 1961; Barshad, 1964; Busacca, 

1982; Harden, in press), and can be used to calculate 

net losses and gains of other elements (Merrill, 1921). 

To calculate Ca loss relative to Zr in that horizon, the 

equation is:

Ca loss =

Ca Zr A - Ca.Zr 

pm A____A pm

Ca Zr. 

pm A

 1

Ca.Zr 

A pm

Ca Zr. 

pm A

where pm refers to the parent material and A to the A 

horizon.

In this calculation, a parent material must also 

be chosen to calculate the net loss or gain of constituents. One alternative would be to use the C horizon 

of each soil as the parent material; however, C 

horizons are weathered or altered to varying degrees 

(see supp. table 1), owing to their varying depth and 

age. For example, note the varying dithionite-extractable-iron content in lowermost C horizons (see supp. 

table 3). The main advantage of using individual C 

horizons for parent materials is that the variation 

between parent materials is incorporated directly into 

the calculation; the disadvantage is that a bias is 

introduced if the C horizons are weathered to varying 

degrees.

One standard for all soils can be used to estimate 

parent material. This method is favorable because the 

parent material is not biased by weathering. (Percent 

loss in this case is calculated to one standard, much as 

laboratory standards are-.used to standardize experimental results.) Clearly, the main disadvantage to 

using single common parent material is that variation 

in parent materials is represented only in replicate 

soils on units of the same age and in the scatter

inherent to time plots; also, the units of percent loss 

are not meaningful if the standard soil used for parent 

material is weathered (negative units are not uncommon, even when the time plots suggest net loss of an 

element). We note that the standard (parent material) 

used for the calculation can be changed without 

affecting the slope of the time curves (rates). Much 

more work is needed to make these calculations more 

reliable for comparison with other studies.

Merrill's equation was used to calculate the 

percent loss for four elements that had significant 

correlations over time relative to Zr (fig. 12). Zr was 

used as the index, and the elemental composition of 

sample V2-C2 was used for the parent material. From 

these calculations, Ca and Mg are lost from the fine 

fraction of A horizons (fig. 13), and Fe and Al are 

gained in the B horizons (fig. 14). It is unclear, 

however, whether the rates of loss and gain are linear 

or exponential, because there are so few points and 

because the youngest two units vary and are somewhat 

similar with respect to percent loss. We examined 

plots of the residuals (predicted ^ minus observed y_), 

but there were no obvious biases to indicate that 

either type of curve is unsuitable. Until more data are 

available from this or similar areas, rates will not be 

calculated because of this problem with curve fitting.

Estimating the Rates of Soil Development

This study documents soil development over 

time, and the next logical use of these data is to 

estimate the rate at which the soils and their properties develop over a geologic timespan. Properties that 

change systematically over time are most conducive to 

estimating rates of development. For the soils of this 

study, these properties include iron oxide content, clay 

content, and the soil-development index (using total 

texture, clay films, rubification, and dry consistence; 

see Harden and Taylor, 1983). Percent loss of elements (figs. 13, 14) is inappropriate for rate calculations at present because it is unclear whether the rates 

are linear or exponential and because there is a large 

uncertainty about parent material.

The paucity of data for Ventura soils makes it 

difficult to ascertain the type of curve that is most 

appropriate for estimating rates of soil development. 

Comparing Ventura with Merced soils helps to consider 

some possible curve shapes because the Merced study 

area (Harden, in press) has soils of a very wide age 

range. For Merced soils, the clay content (fig. 15_A) 

increases nonlinearly; the rates of clay increase appear 

to be highest at first, then decline in later stages of 

soil development. Ventura soils contain consistently 

more clay than Merced soils of similar age (figs. 6, 15), 

but because there are no early Pleistocene Ventura 

soils along the coast, it is unclear whether the rate of 

clay increase in Ventura soils would decline after 

about 100 ka or so, or whether it would be maintained 

as a linear function (fig. 15_A). The steepest part of 

the curve for Merced data is in the first 10 ka, after 

which the slope (rate) falls off significantly.

Time curves for Ventura data (fig. 15) could be 

either linear or nonlinear over long timespans. Some 

authors (Reheis, in press) speculate that exponential

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B13
1.10

0.82

u 0.53

? Q.25

C/}

3 -0.03

CD

-0.32

-0.60 -

1.0

0.5

-0.5

-1.0

-1.5 -,

20 40 60 80

AGE, IN THOUSANDS OF YEARS

100 120 20 40 60 80 

AGE, IN THOUSANDS OF YEARS

100

1.10

0.82

Iz

u 0.53

CC 

LLJ 

CL

? 0.25

C/) 

CO

3 -0.03

CD 

U

-0.32

1.0

0.5

10 2 10 4 10 6 108 

AGE, IN YEARS

1010 1012

-OR

-1.0

 1-5 h

102

D

106 

AGE, IN YEARS

108 10'°

Figure 13. Net losses of Ca (A, _C) and Mg (B, D) from fine (silt plus clay) fraction of A horizons versus 

linear (A, B) and log (C, D) age. Losses calculated according to method of Merrill (1921), using Zr as 

stable index and sample V2-3C2 as parent material. Horizontal lines, age uncertainty; dots, bestestimate age of soils on coastal terraces; circled dots, soils developed in Ventura River gravel (see 

table 1). Solid lines (A-D) approximate trends of data; dashed line (A) indicates trend if linear rates 

are assumed.

rates are typical of weathering processes (Coleman, 

1981), whereas linear rates are more typical of eolian 

accretion rates (Machette, 1985). If eolian input is the 

dominant process responsible for clay accumulation in 

Ventura soils and if accretion rates are maintained for 

geologic timespans, then the rates of clay accumulation at Ventura may be linear and maintained at such 

high values for long time periods. Both linear and 

exponential curves are considered below for estimating 

rates of clay increase. For linear rates, all but the 

soils on Ventura River gravel are used in regressions, 

and only Holocene soils of the Merced study are used 

(Holocene rates are higher than Pliocene and Pleistocene rates at Merced; see fig. 15Aj Harden, in press). 

There is also a question of curve shape for iron oxide 

content and the soil-development index, and both 

linear and exponential functions are considered in 

estimating the rates of these properties (figs. 11, 15C). 

As discussed by Harden and fay lor (1983) and 

Harden (in press), uncertainties in tne ages of the 

deposits must be considered when soil-development

rates are calculated. For data in both linear and 

logarithmic units, we used simple linear regression of a 

roperty versus (I) best-estimate ages for all deposits, 

minimum ages for young and maximum ages for old 

deposits, and (3) maximum ages for young and minimum ages for old deposits (table 3). The combinations 

of constraining ages help to estimate minimum and 

maximum possibte rates of soil development, using 

linear regression.

Both linear and logarithmic transformations were 

used in regressions for soil-development rates. If the 

logarithm of age was used for the jc-axis, the differ-

^Two-error regression (Deming, 1943) would be 

more suitable, but this model does not allow (or 

assumes there is no) natural scatter in the regression 

clearly inappropriate for soils.

B14 Soil Chronosequences in the Western United States
-0.3

oc -0.6

-0.9

-1.2

-1.5 -

-0.3

-0.9

-1.2

-1.5 -

10 2

0.15

-0.10

-0.60

-0.85

-1.1 -

20 40 60 80 100 

AGE, IN THOUSANDS OF YEARS

120 20 40 60 80 100 

AGE, IN THOUSANDS OF YEARS

120

0.15

-0.10

u

ff, -0.35

-0.60

-0.85

-1.1 -

D

-©-

10 4 10 6 108 

AGE, IN YEARS

1010 10 1 10 2 10 4 10 6 10 8 

AGE, IN YEARS

1010 10 12

Figure 14. Net gains of Fe (A, C) and Al (B, D) from fine (silt plus clay) fraction of B horizons versus linear (A, B) 

and log (C, D) age. Losses calculated according to method of Merrill (1921), using Zr as stable index and sample 

VZ-3C2 as parent material. Horizontal lines, age uncertainty; dots, best-estimate age of soils on coastal terraces; 

circled dots, soils developed in Ventura River gravel (see table 1). Negative slope indicates net gain of an element. Solid lines (A-D) approximate trends of data; dashed lines (A, B) indicate trend if linear rates are assumed.

ences between the youngest two units are considered 

to be significant and suggest an exponential function 

(figs. 6, 11). For the soil-development index, tne 

logarithm of soil property was used for the regression 

because soil property versus logarithm of age was bowl 

shaped and because the curve straightened out on a 

log-log plot (Harden and Taylor, 1983). Here, again, 

the residuals were examined, but no biases toward age 

were found. The rates reported for these properties 

(table 3) are constrained to within about 5 percent. In 

comparison, rates for Merced soils had uncertainties of 

about 50 percent, mainly because of the larger age 

uncertainties in ages of those soils.

SUMMARY AND CONCLUSIONS

The systematic change in several soil properties 

with increasing age indicates that at least some parts 

of the marine terraces near Ventura were stable 

enough for soil development to proceed. By studying

the flat, relatively preserved parts of the terraces in 

areas less subject to local slope processes, this study 

demonstrates that marine terraces could be used to 

characterize soil development in coastal regimes. The 

potential for finding datable material at the contact 

between marine and terrestrial deposits makes the 

terraces especially useful for studies of the long-term 

rates of soil development. In addition, new studies on 

the changes in soil development in different parts of 

the terrace surfaces may reveal more information on 

terrace stability and deformation at a larger geographic scale. Because the soils on the Punta Gorda marine 

terrace are considerably less developed than those on 

the Ventura terrace, soils can be used to differentiate 

the marine terraces where other age or correlation 

criteria cannot be used.

Although the age controls on soils of this study 

have some limitations, the available ages allow longterm soil-development rates in Ventura to be compared with those in other areas. The increase of clay 

content in these soils appears to be very rapid in

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B15
150 

X

LLJ 

Q

z 

£ 100

LJJ 

CL

3

> 50

LU

Q 

_J

o

C/)

200

2 150

40 80 120 160 

AGE, IN THOUSANDS OF YEARS

200

I- <

100

50

B

40 80 120 160 

AGE, IN THOUSANDS OF YEARS

200

LLJ CC 

Q <

\± a.

n?$

- o

10 2 104 10 6 10 8 

AGE, IN YEARS

101 10 12

Figure 15. Comparison of soil-development index (A), 

percent clay (B), and total iron oxide content (C) in 

Ventura soils (shaded boxes) with those in Merced soils 

(unshaded boxes). Dithionite-extractable-iron and clay 

contents were multiplied by horizon thickness and bulk 

density, and the products were summed for each profile. For each geologic unit, vertical dimension of box 

represents mean and one standard deviation of all soils 

in the unit, and horizontal dimension represents age 

uncertainty. Solid lines approximate trends of data; 

dashed lines indicate trend if linear rates are assumed.

comparison with clay accumulation in the Central 

Valley of California. In contrast to this rapid clay 

accumulation, however, there is no apparent change in 

clay mineralogy with increasing age. This absence of 

mineral alteration suggests that the clays are not 

authigenic and that most of the clay is probably 

deposited by eolian and slope processes and by physical 

breakdown of coarser grains.

Many chemical parameters, such as organiccarbon content, extractable acidity, dithionite-extractable-iron content, and total chemical analysis, 

change with increasing age. Increasing extractable 

acidity and decreasing total Ca and Mg suggest that 

the soils are relatively well drained and leached over 

time. Extractable iron oxides and total analysis of Fe 

indicate that iron oxides are forming over time but 

that some Fe may be lost by leaching in A horizons. 

Some iron oxides may also be deposited with eolian or 

depositional clays. More mineralogic analyses are 

needed to distinguish between clay production by in 

place processes and influx of previously weathered 

materials to the soil profiles.

REFERENCES CITED

Barshad, Isaac, 1964, Soil development, chap. 1 of 

Bear, F.E., ed., Chemistry of the soil: New 

York, Reinhold, p. 1-5Z.

Bloom, A.L., Broeker, W.S., Chappell, J.M.A., Matthews, R.K., and Mesolella, K.J., 1974, Quaternary sea level fluctuations on a tectonic coast: 

New 230Th/234U dates from the Huron Peninsula, New Guinea: Quaternary Research, v. 4, 

no. 2, p. 185-205.

Burke, R.M., and Birkeland, P.W., 1979, Reevaluation 

of multiparameter relative dating techniques and 

their application to the glacial sequence along 

the eastern escarpment of the Sierra Nevada, 

California: Quaternary Research, v. 11, no. 1, p. 

21-51.

Busacca, A.J., 1982, Geologic history and soil development, northeastern Sacramento Valley, California: Davis, University of California, Ph.D. 

thesis, 348 p.

Busacca, A.J., Aniku, J.R., and Singer, M.J., 1984, 

Dispersion of soils by an ultrasonic method that 

eliminates probe contact: Soil Science Society 

of America Journal, v. 48, no. 5, p. 1125-1129.

 1984, Dispersion of soils by an ultrasonic method 

that eliminates probe contact: Soil Science 

Society of America Journal, v. 48, no. 5, p. 1125- 

1129.

Colman, S.M., 1981, Rock-weathering rates as functions of time: Quaternary Research, v. 15, p. 

250-264.

Dembroff, G.R., 1982, Tectonic geomorphology and 

soil chronology of the Ventura Avenue Anticline,

B16 Soil Chronosequences in the Western United States
Table 3. Estimated rates of soil development

Age used for trials (ka)

Unit

Post-Sea Cliff

Po*it S&3 Cliff

II 

T

Property

Clay (n=8)

Dithioniteextractable 

iron.

Soi 1 -development index 

(SDI).

Regression

Slope

^-intercept

JS

Slope

^-intercept

^

Slope

^-intercept

_S

Units

(9/cm2 )/log10 yr

g/cn/ 

.01 percent

g/cm2

(g/cm2 )/log10 yr

g/cn/ 

.01 percent

g/cm2

Iog 10 SDI/log 10 yr

Iog 10 SDI 

.01 percent

Iog 10 SDI

0.7

 2

- 40

on

64.2

-172.0 

.716

40.0

2.16

-5.53 

.756

1.22

.751

1.76 

.914

10.23

1

5.6

60

100

67.9

-201.0 

.70

41.0

2.29

-6.53 

.742

1.26

.804

-2.14 

.916

.23

0.5

1.5

30

60

65.2

-170.0 

.714

43.86

2.21

-5.48 

.762

1.21

.767

-1.74 

.922

.22

Ventura County, California: Santa Barbara, 

University of California, M.A. thesis, 15Z p.

Dembroff, G.R., Johnson, D.L., Keller, E.A., and 

Rockwell, T.K., 1982, The soil geomorphology 

and neotectonics of the Ventura River and 

central Ventura basin, California: American 

Society of Agronomy-Soil Science Society of 

America-Geological Society of America annual 

meeting, Anaheim, Calif., 1982, field guide for 

soil-geomorphology tour, p. 285-298.

Deming, W.E., 1943, Statistical treatment of data: 

New York, John Wiley, 261 p.

Dethier, D.T., and Bethel, John, 1981, Surficial 

deposits along the Cowlitz River near Toledo, 

Lewis County, Washington: U.S. Geological 

Survey Open-File Report 81-1043, 10 p.

Harden, J.W., 1982, A quantitative index of soil 

development from field descriptions: Examples 

from a chronosequence in central California: 

Geoderma, v. 28, no. 1, p. 1-28.

 in press, Soils developed in granitic alluvium near 

Merced, California: U.S. Geological Survey 

Bulletin 1590-A.

Harden, J.W., and Marchand, D.E., 1977, The soil 

chronosequence of the Merced River area 

[California], in Singer, M.J., ed., Soil development, geomorphology, and Cenozoic history of 

the northeastern San Joaquin Valley and adjacent 

areas, California, chap. 6 £f_ American Society of

Agronomy-Soil Science Society of AmericaGeological Society of America, joint field 

session, 1977, guidebook: Davis, Calif., American Society of Agronomy.

 1980, Quaternary stratigraphy and interpretation 

of soil data from the Auburn, Oroville, and 

Sonora areas along the Foothills fault system, 

western Sierra Nevada, California: U.S. Geological Survey Open-File Report 80-30, 57 p.

Harden, J.W., and Taylor, E.M., 1983, A quantitative 

comparison of soil development in four climatic 

regimes: Quaternary Research, v. 20, no. 3, p. 

342-359.

Kingston, M.S., and Gailitis, V., 1976, The geographic 

variation of salt precipitated over western 

Australia: Australian Journal of Soil Science, v. 

14, p. 319-335.

Jenny, Hans, 1979, The soil resource: Origin and 

behavior: New York, Springer-Verlag (Ecological 

Studies, v. 37), 377 p.

Kerr, P.F., Stroud, R.A., and Drew, I.M., 1971, Clay 

mobility in landslides, Ventura, California: 

American Association of Petroleum Geologists 

Bulletin, v. 55, no. 2, p. 267-291.

Lajoie, K.R., Kern, J.P., Wehmiller, J.F., Kennedy, 

G.L., Mathieson, S.A., Sarna-Wojcicki, A.M., 

Yerkes, R.F., and McCrory, P.F., 1979, Quaternary marine shorelines and crustal deformation, 

San Diego to Santa Barbara, California, in

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B17
Abbott, P.L., Geologic excursions in the southern 

California area: San Diego, Calif., San Diego 

State University, Department of Geological 

Sciences, p. 3-15.

Lajoie, K.R., Sarna-Wojcicki, A.M., and Yerkes, R.F., 

1982, Quaternary chronology and rates of crustal 

deformation in the Ventura area, California, in 

Neotectonics of the Ventura basin, field trip 3 of 

Cooper, J.D., compiler, Neotectonics in southern 

California: Geological Society of America, 

Cordilleran Section annual meeting, 78th, 

Anaheim, Calif., volume and guidebook, p. 43-51.

Machette, M.N., 1983, Geologic map of the southwest 

quarter of the Beaver quadrangle, Beaver 

County, Utah: U.S. Geological Survey Miscellaneous Investigations Series Map 1-1444, scale 

1:24,000.

 1985, Calcic soils of the southwestern United 

States, in Weide, D.L., ed., Soils and Quaternary 

geology of the southwestern United States: 

Geological Society of America Special Paper 

203, p. 11-22.

Machette, M.N., and Personius, S.F., 1984, Map of 

Quaternary and Pliocene faults in the eastern 

part of the Aztec 1° by 2° quadrangle and the 

western part of the Raton 1° x 2° quadrangle, 

northern New Mexico: U.S. Geological Survey 

Miscellaneous Field Studies Map MF-1465-B, 14 

p., scale 1:250,000.

Machette, M.N., and Steven, T.A., 1983, Geologic map 

of the northwest quarter of the Beaver quadrangle, Beaver County: U.S. Geological Survey 

Miscellaneous Investigations Series Map 1-1445, 

scale 1:24,000.

Machette, M.N., Steven, T.A., Cunningham, C.G., and 

Anderson, J.J., 1983, Geologic map of the Beaver 

quadrangle, Beaver and Piute Counties, Utah: 

U.S. Geological Survey Miscellaneous Investigations Series Map 1-1520, scale 1:50,000.

Marchand, D.E., and Allwardt, Alan, 1981, Late 

Cenozoic stratigraphic units, northwestern San 

Joaquin Valley, California: U.S. Geological 

Survey Bulletin 1470, 70 p.

Mehra, O.P., and Jackson, M.L., I960, Iron oxide 

removal from soils and clays by a dithionitecitrate system buffered with sodium bicarbonate: Clays and Clay Minerals v. 7 , p. 317-327.

Meixner, R.E., and Singer, M.J., 1981, Use of field 

morphology rating system to evaluate soil 

formation and discontinuities: Soil Science, v. 

131, no. 2, p. 114-123.

Merrill, G.P., 1921, Rocks, rock weathering, and 

soils: New York, Macmillan, 241 p.

Muhs, D.R., 1980, Quaternary stratigraphy and soil 

development, San Clemente Island, California: 

Boulder, University of Colorado, Ph.D. thesis, 

255 p.

 1982, A soil chronosequence on Quaternary 

marine terraces, San Clemente Island, California: Geoderma, v. 28, no. 3-4, p. 257-283.

Natland, M.L., 1952, Pleistocene and Pliocene stratigraphy of southern California: Los Angeles, 

University of California, Ph.D. thesis, 165 p.

Palmer, L.A., 1967, Marine terraces of California, 

Oregon and Washington: Los Angeles, University 

of California, Ph.D. thesis, 308 p.

Putnam, W.C., 1942, Geomorphology of the Ventura 

region, California: Geological Society of 

America Bulletin, v. 53, no. 5, p. 691-754.

Quaide, W.L., 1957, Clay minerals from the Ventura 

Basin, California: Journal of Sedimentary 

Petrology, v. 27, no. 3, p. 336-341.

Reheis, M.C., 1984, Chronologic and climatic control 

on soil development, northeastern Bighorn Basin, 

Wyoming and Montana: Boulder, University of 

Colorado, Ph.D. thesis, 293 p.

 in press, Gypsic soils on the Kane alluvial fans, 

Big Horn County, Wyoming: U.S. Geological Survey Bulletin 1590-C.

Rockwell, T.K., 1983, Soil chronology, geology, and 

neotectonics of the north central Ventura basin, 

California: Santa Barbara, University of California, Ph.D. thesis, 522 p.

Sarna-Wojcicki, A.M., Bowman, H.R., Meyer, C.E., 

Russell, P.C., Asaro, Frank, Michael, Helen, 

Rowe, J.J., Baedecker, P.A., and McCoy, Gail, 

1980, Chemical analysis, correlations, and ages 

of late Cenozoic tephra units of east-central and 

southern California: U.S. Geological Survey 

Open-File Report 80-231, 53 p.

Sarna-Wojcicki, A.M., Williams, K.M., and Yerkes, 

R.F., 1976, Geology of the Ventura fault, 

Ventura County, California: U.S. Geological 

Survey Miscellaneous Field Studies Map MF-781, 

scale 1:6,000, 3 sheets.

Singer, M.J., and Janitzky, Peter, eds., 1986, Field and 

laboratory procedures used in a soil chronosequence study: U.S. Geological Survey Bulletin 

1648, 49 p.

Soil Survey staff, 1975, Soil taxonomy a basic system 

of soil classification for making and interpreting 

soil surveys: U.S. Department of Agriculture 

Handbook 436, 154 p.

Walker, A.L., 1983, The effects of magnetite on 

oxalate- and dithonite-extractable iron: Soil 

Science Society of America Journal, v. 47, no. 5, 

p. 1022-1026.

Wild, A., 1961, Loss of zirconium from 12 soils derived 

from granite: Australian Journal of Agricultural 

Resources, v. 12, p. 230-305.

Yaalon, D.H., and Lomas, J., 1970, Factors controlling 

the supply and chemical composition of aerosols 

in a near-shore and coastal environment: 

Agricultural Metereology, v. 7, p. 443-454.

Yeats, R.S., 1977, High rates of vertical crustal 

movement near Ventura, California: Science, v. 

196, no. 4287, p. 295-298.

Yerkes, R.F., and Lee, W.H.K., 1979, Late Quaternary 

deformation in the western Transverse Ranges, 

California: U.S. Geological Survey Circular 799- 

B, p. 27-37.

Yerkes, R.F., Sarna-Wojcicki, A.M., and Lajoie, K.R., 

in press, Geology and Quaternary deformation of 

the Ventura area, Ventura County, California: 

U.S. Geological Survey Professional Paper 1339.

B18 Soil Chronosequences in the Western United States
SUPPLEMENTARY TABLES

[See Singer and Janitzky (1986) for analytical methods]
Supplementary Table 1. Field descriptions

Grade

m, massive

sg, single grained

1. weak

2. moderate

3. strong

EXPLANATION 

(see Soil Survey staff, 1975)

SOIL STRUCTURE 

Size

vf, very fine (v thin)

f, fine (thin)

m, medium,

c, coarse (thick)

vc, very coarse

(v thick)

Type

gr, granular

pi, platey

pr, prismatic

cpr, columnar

abk, angular blocky

abk, subangular blocky

If two structures-listed as primary and secondary 

SOIL TEXTURE

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

Dry

lo, loose

so, soft

sh, slightly hard

h, hard

vh, very hard

eh, extremely hard

Moist

SOIL CONSISTENCE 

Wet

lo, loose

vfr, very friable

fr, friable

fi, firm

vf, very firm

efi, extremely firm

so, nonsticky

ss, slightly sticky

s, sticky

vs, very sticky

po, nonplastic

ps, slightly plastic

p, plastic

vp, very plastic

HORIZON BOUNDARIES

Distinctness

va, very abrupt 

a, abrupt 

c, clear 

g, gradual 

d, diffuse

Topography

s, smooth

w, wavy

i, irregular

b, broken

Size

vf, very fine 

f, fine 

m, medium 

co, coarse

Abundance

1 few

2 common

3 many

ROOTS AND PORES 

Pore Shape

tub, tubular 

ir, irregular 

v, vesicular

Frequency

Vi, very few 

it 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

B20 Soil Chronosequences in the Western United States
Supplementary Table 1. Field descriptions Continued

[Analyst: J.W. Harden, U.S. Geological Survey; and others]

No.

1

2

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

30

30

31

Sample Horizon

V2 A

2C1

3C2

V7 spoil

All

A12

2C

VI All

A12

A13

AtC

Clca

2C2ca

V6 All

A12

Clca

2C2ca

V4 All

A12

A13

282t

3B3H

4B32t

5B33t

6C

7C

V5 All

A12

A3

2B1

2B2U

3B22t

4B23t

5B31

6B32

7B33

8C

Basal Lower

(cm)

5 c,w

39 c,s

60+

14

55 diff

74 a

100

17 diff

53 g,w

82 g,i-w

120 g,w

140 s,a

160

50 g,«

60 g,w

100

115+

20 d,w

53 gr,«

83 c,w

115 c,s

131 c,s

141 c,s

158

300

310

17 c,w

51 c,w

60 a,i

79 c,w

98 c,w

106 c,w

118 c,w

129 c,w

134 c,w

149 c,w

155

Moist

10YR3/3

2.5Y3.5/4

2.5Y6/4

--

10YR3/1

10YR3/1

10YR3/2

10YR4/3

2.5Y5/4

2.5Y5/4

"

10YR2/1

10YR2/1

2.5Y4/2

2.5Y5/4

--

--

__

--

" 

10YR3/1

10YR3/1

10YR3/3

7.5YR5/4

7.5YR5/4

--

--

--

--

--

~~

Dry

--

--

--

10YR4/2

10YR5/2

2.5Y6/4

--

2.5Y7/4

10YR3/2

10YR3/2

2.5Y6/4

2.5Y7/4

..

--

--

-_

-_

 

10YR4/2

10YR4/2

10YR4/3

10YR6/4

7.5YR6/4

--

--

Consistenc

Alluvium, 0.7 Ka

SL 1 m gr -- fr

SL m fr

SL m-sg -- fr

LS sg -- lo

LS sg lo

cobC

Alluvium, 2 Ka

SCL 2m gr, sh lo

1 f sbk

SCL 2 m gr, ~ lo

1 m sbk

SL m,l m sbk lo

SL m lo

SL m lo

SL

L 2 m gr, sh lo

1 m sbk

L -- lo lo

SL lo

L

Alluvium, 40 Ka

CL 2m pr, vh vfi

If sbk

CL m pr vh vfi

CL 1 m abk fi

CL 1 m abk

SCL m -- fi

SCL -- -- lo

CL

SL

L

L 2 f pr vh fi

L 2 f sbk sh fr

SL 1 f sbk sh fr

SL m, 1 f abk -- fr

SCL m, 1 f abk -- fr

SL m, 1 f abk fr

SCL m, 1 f abk fr

SCL m, 1 f abk 

SCL m, 1 f abk 

SCL m, 1 f abk 

L

e

Wet Roots Pores

ss.po 3m, 2f 2m tub

ss.ps 3m, 2f,

Ico

so.po 1m

so.po

so.po

3f,3vf

tub

ss.po 2m, 2f 2m, If

tub

ss.po 2m, 2f, 2m, 2f,

Ico tub

ss.po 2m, 2f, 2m, 2f,

Ico Ivf tub

ss.po Ico, 2m, 2f,

1m Ivf tub

ss.po 2vf tub

..

ss.po 3f,3vf, 3f,

2m 2mtub

ss.po If, Ivf, 2f,2vf

3vf tub

ss.po -- 3vf,

2ftub

s.ps

vs.pv 3vf, 2f,2vf

2f tub

vs.pv 3vf, If, Ivf

2f tub

vs.pv If, If, Ivf

Ivf tub

vs.pv 2f 2-3f,

Ivftub

s,p l-2f 3f,

2mtub

ss.po Iftub

s,ps 3ftub

.-

s,p If, Iv.lvf,

Ivf Imtub

s.p 2f,lm 3m

2ftub

Ivfint

s,p 2f,lm 3m,

3ftub

ss.po 3f,

2mtub

ss.ps If 3f,2m

tub

ss.po If 2vfint,

Iftub

s,p -- 2f,lm

tub

ss.po 2vfint,

If tub

s,p -- 2f,lm tub

ss.po 2vfint,

Iftub

Clay 

Films

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2nbrw

2mkbrw,

2mkpo

0

2nbr,

2npo,

Imkbrw

0

0

0

0

0

Inpo,

Inbrw

Imkbrw,

Inpo,

?nhrw

2nbrw

2mkbr,

2mkpo,

1kb rw

0

0

3nbr

0

 SssliJ

r

pH Texture

7.4 SL

7.6 SL

7.6 SL

7.6 LS

7.8 LS

7.2 SCL

6.8 SCL

7.0

SL

SL

8.2 SL

8.2 SL

7.3 L

7.5 L

8.2 SL

8.2 L

CL

CL

CL

CL

SL

SL

SL

SL

L

L

L

SL

SL

SL

SL

SL

SL

SL

L

ted Parent 

naterial

Wet 

Consistence

so.po

so,po

so.po

so.po

so,po

so.po

ss.po

ss.po

55, PO

ss.po

55, po

55, pO

55, PO

ss.po

ss.po

ss.po

vs.pv

vs.pv

vs.pv

vs.pv

55, pO

55, PO

ss.po

ss.po

ss.po

s.P

S.P

ss.po

ss.po

55, PO

ss.po

ss.po

55, pO

55, PO

ss.po

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B21
Supplementary Table 1. Field descriptions Continued

No. Sample Horizon

Basal Lower

depth Boundary 

(cm)

Moist

Color

Dry

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

56

57

58

59

60

61

62

63

64

65

66

67

V8 All

A12

2A3

3B2H

4B22tca

5B31ca

6B32ca

7B33ca

8B34 a

burl d?

9Clc

buri d?

10C2 a

buri d?

V9 Al

2A3

2B21t

3B22t

4B31t

5B32t

5B33ca

6Cca

V3 All

A12

A31

A32

2B2t

2B3H

3B32t

3Cox

4C2ox

V10 All

A12

Bit

2B21t

3B3H

4B32t

2.5 c,w

17 c,w

54 g,w

9D g,w

152 c,w

183 c,w

190 c,w

200 c,w

217 c,w

269

300

13 g,w

47 g,w

68 g,w

100 g,w

157 g,w

201

266

311

7 c,w

25 g,

33 g,w

58 c,w

112 g,w

147 g,w

182

272

280

6 c w

62 c w

88 d l

152 g w

260 g w

300+

10YR3/1

10YR3/1

7.5YR3/2

.5YR4/4

.5YR5/4

.5YR3/2

.5YR4/4

.5YR4/4

.5YR5/6

10YR4/4

7.5YR4/4

10YR4/4

7.5YR4/4

10YR4/4

10YR3/2

7.5YR3/2

7.5YR4/4

10YR4/4

10YR4/4

2.5Y4/4

10YR4/4

10YR5/4

2.5Y5/4

10YR3/2

10YR3/2

10YR3/3

7.5YR4/2

5YR4/6

5YR4/6

7.5YR5/6

5YR4/4

7.5YR5/6

7.5YR5/6

7.5YR5/6

--

--

"

10YR5/3

10YR5/3

--

7.5YR5/4

7.5YR5/4

10YR5/6

7.5YR5/4

10YR6/6

10YR6/4

10YR5/3

7.5YR5/3

10YR5/4

10YR6/6

10YR5/4

10YR6/6

10YR6/6

2.5Y7/4

10YR5/3

10YR5/3

10YR4/3

--

"

--

--

 "

L

L

C

CL

CL

SiCL

L

SlCL

SiCL

L

L

L

CL

C

SiC

SlC

SL

L

L

SL

SL

SL

SCL

SCL

SCL

SCL

SL

SL

SL

SL

SL

SL

SL

SL

2 <n 9 r

2 c sbk

1 m pr,

1 m sbk

1 f pr

2 f pr

2 f pr

1 f sbk

1 f pr

m

m

.-

2 m sbk

2 m pr

2 m pr

2 in pr

1 f pr

1 f pr

c sbk

sg

All

3 m gr

2 m sbk

If m sbk

If m sbk

m,l m sbk

m,l m sbk

sg

sg

sg

m

m

m, m-~c pr

m

m

h

vh

vh

vh

vh

h

sh

vh

vh

h

.-

vh

vh

vh

vh

vh

sh

.-

--

vium,

sh

sh

sh

sh

--

--

--

"

_

__

--

"

Consistence

1 Moist Wet

fi s,po

vfi s,po

vfi vs.pv

vfi vs.pv

vfi vs.pv

fi vs.pv

fi s,ps

vfi vs.pv

fi ss.po

fi ss.po

..

fi ss.po

fi so.pv

fi so.pv

fr

fi vs.pv

fr ss, po

SO ka

fr so.po

fr so.po

fi ss.ps

fi ss.ps

fr-fi s,p

lo s,p

lo ss.po

1 0 S 0 , po

lo

__

--

-.

--

--

Assumed Parent 

material

Clay

Roots Pores Films pH

3f,3vf 0

2f,2vt 2f,2vf, 0

Imtub

If.lvf If 0

Ivf Imtub

If, Inbrw,

Ivftub Inbrpo

If If, Ivf 3mkpf

tub

Ivf 3f,2"i 3mkbr,

tub 3mkbf,

3mkpo

Ivf 3f,2m Inbrw

tub

Ivf 3f,2«n Inbrw,

tub 3mkpf

Ivf 3f,2m 1 2mkpo,

tub 1 2mkbrw

l-2f Inbrw

tub

0

2f,2vf 3f,lvf, 0 6.6

tub

l-2f, 2f,2 vfi, 0 7.6

l-2vf vf Imtub

If, Ivf 1m, If, Inbrw 7.6

Ivftub

Ivf 2f, 2mkbrw

2 vf,

Imtub

Ivf If, Ivf 3mkbr

tub 2kpf

3f,?m Inbrw

tub

3m,2co Inbrw,

tub Inpo

0

3vf, 2vftub 0

2m

2vf, 3vf, 0

2f,2m 2mtub

2vf, 2vf, 0

If, Ira 2f,2mtub

2vf, 2-3vf, 0

1m 2f,lm

tub

Ivf 3 f, 4mkbr,

2 tuh 3kbrw

3 f, 3n-mkbr,

2 tub Imkhrw

1 tub 3nbr,

Ikbrw

--

"

-_

-.

--

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

SL

Wet

s,po

s,po

s,po

s.po

s,po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

ss.po

so,po

so.po

so.po

so.po

so.po

so.po

so.po

so.po

so.po

 __

-- 

-- 

 -_

" 

B2Z Soil Chronosequences in the Western United States
Supplementary Table 2. Physical properties

[Analysts: J.Baker, R. Johnson, J. Lindsay, B. McCall, H.G. Rose, G. Sellers, J.Taggert, J.S. Wahlberg]

Percentage

No.

1

2

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

Sample

V2

V2

V2

V7

V7

VI

VI

VI

VI

VI

V6

V6

V6

V6

V4

V4

V4

V4

V4

V4

V4

V4

V5

V5

V5

V5

V5

V5

V5

V5

V5

V5N

V5N

V5N

V5N

Horizon

A

2C1

3C2

All

A12

All

A12

A13

A+C

Clca

All

A12

Clca

2C2ca

All

A12

A13

2B2t

3B31t

4B32t

5B33t

7C only

All

A12

A3

2B1

2B21t

3B22t

4B23t

5B31-7B33

8C

All

B21t

B3

2Clox

Basal

depth

(cm)

5

39

60+

55

74

17

53

82

120

160

50

60

100

115

20

53

83

115

131

141

158

310

17

51

60

79

98

106

118

149

155+

23

54

89

100+

Total vco

>2 mm

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

5-10

5

5-10

0

0

0

0

5

5

1-2

0

0

0

0

0

0

0

sand

63.1

61.9

74.8

86.1

B7.8

53.1

57.4

62.5

65.7

63.8

44.3

50.9

61.6

50.9

31.3

33.7

25.4

31.5

47.3

50.1

23.7

37.2

50.4

48.0

54.4

64.2

57.7

67.5

56.9

56.8

37.9

46.0

36.5

31.2

54.8

sand

Al luvium,

1.9

2.9

2.2

0.6

1.0

Al luvium,

1.6

1.3

1.0

0.8

0.3

2.2

2.4

9.3

4.6

Al luvium,

0.1

0.1

0.2

0.1

1.2

0.3

0.4

0.0

0.3

0.4

0.3

0.9

1.2

0.9

0.8

1.5

0.1

0.5

0.2

0.1

0.2

CO

sand

0.7 ka

6.2

6.7

14.2

5.7

6.3

2 ka

4.9

5.2

5.0

5.4

1.8

4.6

5.6

12.2

7.1

40 ka

0.2

0.1

0.2

0.3

1.3

0.7

0.4

0.3

2.3

2.4

2.6

5.1

4.2

2.9

2.6

4.6

0.6

2.7

2.1

1.3

4.3

m

sand

7.3

8.3

14.4

28.3

28.3

6.6

7.0

7.4

8.0

4.2

5.1

6.9

8.3

5.9

0.4

0.4

0.4

0.5

1.4

1.1

0.4

0.4

5.4

5.3

5.9

8.1

6.9

5.7

4.7

9.1

2.3

4.8

3.9

2.7

7.5

of <2-mm fraction

fi+vfi

sand

47.6

44.0

44.1

51.5

52.2

40.0

44.0

49.0

51.6

57.6

32.4

36.1

31.8

33.3

30.7

33.0

24.7

30.5

43.4

55.0

22.6

36.5

42.4

34.9

45.6

50.0

45.4

57.9

40.6

41.6

35.0

37.9

30.2

27.1

42.8

Silt

18.8

21.7

13.4

7.4

6.7

26.5

22.0

18.8

17.8

18.2

34.1

29.5

22.2

28.9

31.1

27.4

34.7

29.8

25.3

22.8

39.2

41.3

28.0

30.5

26.1

20.3

22.1

17.3

19.8

26.9

47.0

33.0

32.3

37.1

31.0

<2-vim

clay

18.1

16.3

11. B

6.5

5.5

20.4

20.6

18.7

16.5

18.0

21.5

19.6

16.2

20.2

37.5

38.9

39.9

38.7

27.4

20.1

37.1

21.5

21.6

21.5

19.5

15.5

20.2

15.2

23.3

16.3

15.1

21.0

31.2

31.7

14.2

<l-nm

clay

15.1

13.1

9.4

6.2

4.8

16.6

17.3

15.1

13.7

14.1

17.6

16.9

13.7

16.4

32.8

33.6

34.3

33.6

22.1

16.4

29.7

16.6

17.5

17.6

15.5

12.2

16.9

12.1

18.6

13.8

10.2

18.9

28.8

27.6

11.7

Bulk

density

(g/cm3 )

1.34

1.65

1.63

1.71

1.54

1.40

1.40

1.38

1.32

1.52

1.35

1.44

1.74

1.15

1.74

1.76

1.84

1.63

1.56

1.64

1.58

1.42

1.54

1.48

1.60

1.72

1.72

1.72

1.78

1.73

1.92

1.50

1.78

1.76

1.74

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B23
Supplementary Table 2. Physical properties Continued

Percentage

No. Sample Horizon

Basal

depth

(cm)

Total vco

>2 mm sand sand

CO

sand

m

sand

Alluvium over Marine Terrace, 80

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

V8

V8

V8

V8

V8

V8

V8

V8

V8

V8

V9

V9

V9

V9

V9

V9

V9

V9

V3

V3

V3

V3

V3

V3

V3

V3

V10

V10

V10

V10

V10

V10

All

2A3 only

3B2H

4B22tca

5B31ca

6B32ca

7B33ca

buried?

BB34ca

buried?

9Clca

buried?

10C2ca

buried?

Al

2A3

2B21t

3B22t

4B3H

5B32t

5B33ca

6Cca

All

A12

A31&A32

2B2t

2B31t

3B32t

3Cox

4C2ox

All

A12

Bit

2B21t

3B31t

4B32t

2.5

54

90

152

183

190

200

217

269

300

13

47

68

100

157

201

266

311

7

25

58

112

147

182

272

280

6

62

88

152

260

300+

5-10

0

0

0

0

0

0

0

0

0

0

__

__

__

__

5

60

60

5

5

55

65

5

50

50

50

25

70

50

37.8

31.2

45.2

22.1

10.4

34.8

9.9

18.5

34.0

27.9

39.8

30.0

25.9

13.5

16.6

28.2

27.4

46.3

64.0

55.5

57.6

60.7

67.6

67.3

73.4

77.2

67.8

63.4

59.1

54.7

60.4

65.9

0.3

0.2

1.9

0.1

0.0

0.0

0.0

0.0

0.3

1.0

0.6

0.4

0.3

0.0

0.1

0.2

0.7

0.2

Al luvium,

2.6

1.9

2.6

6.5

11.8

16.8

18.8

7.5

1.6

1.1

3.6

4.4

9.2

8.8

0.7

1.5

5.2

0.9

0.2

0.0

0.0

0.1

0.7

1.1

1.4

1.4

1.2

0.4

0.3

0.4

0.5

0.5

80 ka

6.1

5.4

6.7

13.8

21.7

18.7

19.9

29.5

5.8

5.4

8.5

11.4

15.6

14.8

1.4

2.5

6.2

1.8

0.3

0.1

0.1

0.2

1.4

1.2

2.1

2.5

2.4

0.9

0.7

1.0

0.6

0.7

6.7

6.4

6.6

10.2

14.2

11.2

13.2

21.2

8.0

7.6

7.4

7.5

9.6

10.0

of <2-mm fraction

fl+vfi

sand

ka

35.3

27.1

31.9

19.3

9.9

34.6

9.8

18.2

31.6

24.5

35.5

25.7

22.0

12.2

15.6

26.7

35.6

44.7

48.5

41.7

41.8

30.2

20.0

20.6

21.5

19.1

52.3

49.2

39.5

31.4

25.9

32.3

Silt

45.3

27.5

25.8

46.3

54.8

46.6

52.3

53.4

45.6

47.1

42.5

33.2

33.5

44.7

4B.3

46.9

47.7

39.1

23.8

30.2

25.0

15.7

13.2

13.8

11.8

12.4

21.5

24.2

26.1

17.3

16.5

17.6

<2-pm

clay

16.9

41.3

29.0

31.6

34.7

18.7

37.7

28.1

20.4

25.0

17.7

36.7

40.6

41.8

35.1

24.9

24.9

14.6

12.2

14.3

17.4

23.6

19.2

18.9

14.8

10.4

10.7

12.4

14.9

28.0

23.1

16.5

<l-pm

clay

14.8

39.0

26.6

28.0

29.2

16.1

30.9

23.4

16.8

20.3

14.6

33.2

36.8

35.9

31.2

20.7

20.2

11.9

9.1

10.8

13.9

20.8

16.3

16.1

12.6

8.0

8.3

9.6

11.6

25.6

20.7

14.4

Bulk

density

(g/cm3 )

1.53

1.84

1.86

1.81

1.70

1.64

1.64

1.56

1.58

1.55

1.60

1.87

1.86

1.85

1.60

1.56

1.52

1.52

1.34

1.44

1.48

1.84

1.80

1.72

1.82

1.57

1.33

1.47

1.88

1.94

1.88

2.06

B24 Soil Chronosequences in the Western United States
Supplementary Table 3. Extractive chemical analyses

[CEC, cation-exchange capacity. Analysts: P. Janitzky, R. Meikner under M.J. Singer, University of California, Davis]

No. Sample

Percentage of <2-mm _____ _ meg/lOQg soil _ _____

Basal Total DFganic Exchange Exchange Exchange Exchange Exchange pH 

Horizon depth N C Na K Ca Mg H CEC 1:1 H 9 0 Fe 

(cm)

Percentage of <2-mm

A1

Alluvium, 0.7 ka

1 V2

2 V2

3 V2

4 V7

5 V7

A

2C1

3C2

All

A12

5

3960-1-

55

74

2.74

0.37

0.22

0.66

0.44

1.42

1.33

1.37

0.00

0.06

2.01

0.86

0.57

0.45

0.28

Al luvium,

6 VI

7 VI

8 VI

9 VI

10 VI

11 V6

12 V6

13 V6

14 V6

All

A12

A13

A-t-C

Clca

All

A12

Clca

2C2ca

17

53

82

120

160

50

60

100

115

2.32

1.17

0.61

0.45

0.24

3.22

1.50

0.52

0.36

1.12

1.37

1.01

1.06

0.97

0.11

0.00

0.11

1.14

1.63

1.08

0.52

0.52

0.52

1.52

1.02

0.53

0.77

Al 1 uvium,

15 V4

16 V4

17 V4

18 V4

19 V4

20 V4

21 V4

22 V4

23 V5

24 V5

25 V5

26 V5

27 V5

28 V5

29 V5

30 V5

31 V5

32 V5N

33 V5N

34 V5N

35 V5N

All

A12

A13

2B2t

3B3H

4B32t

5B33t

7C only

All

A12

A3

2B1

2B21t

3B22t

4B23t

5B31-7B33

8C

All

B21t

B3

2Clox

20

53

83

115

131

141

158

310

17

51

60

79

98

106

118

149

155-K

23

54

89

100+

1.82

1.08

0.86

0.30

0.12

0.10

0.10

0.08

1.71

1.26

0.78

0.24

0.22

0.18

0.17

0.10

0.09

2.46

0.74

0.43

0.11

0.69

1.74

3.65

6.09

5.38

3.76

6.09

3.70

0.38

1.01

0.87

1.07

0.87

0.87

1.22

1.22

1.42

0.11

0.62

2.47

1.14

Al 1 uvium over

36 V8

37 V8

38 V8

39 V8

40 V8

41 V8

42 V8

43 V8

44 V8

45 V8

46 V9

47 V9

48 V9

49 V9

50 V9

51 V9

52 V9

53 V9

All

2A3 only

3B21t

4B22tca

5B31ca

6B32ca

7B33ca

buried?

8B34ca

buried?

9Clca

buried?

10C2ca

buried?

Al

2A3

2B21t

3B22t

4B31t

5B32t

5B33ca

6Cca

2.5

54

90

152

183

190

200

217

269

300

13

47

68

100

157

201

266

311

1.56

0.71

0.27

0.14

0.09

0.08

0.13

0.07

0.06

0.09

1.63

0.86

0.67

0.30

0.15

0.10

0.10

0.06

0.00

2.52

3.96

5.13

6.33

3.38

4.83

4.83

2.81

2.81

0.00

1.97

2.80

6.02

6.37

5.78

4.64

2.74

1.27

0.65

0.51

0.48

0.43

0.43

0.48

0.29

1.02

0.82

0.40

0.36

0.40

0.56

0.40

0.36

0.27

1.18

0.37

0.37

0.29

Marine

0.86

0.28

0.12

0.20

0.36

0.20

0.45

0.36

0.20

0.36

0.36

0.36

0.29

0.36

0.56

0.56

0.56

0.56

17.35

10.70

8.48

6.91

5.36

2 ka

14.47

12.01

11.08

11.26

12.01

22.33

19.22

14.52

14.16

40 ka

18.41

20.89

19.30

16.59

11.08

9.59

15.23

11.93

15.36

15.62

14.27

9.59

14.08

9.78

15.23

10.33

8.31

16.68

18.66

16.92

5.44

Terrace,

8.00

19.90

14.30

17.24

16.62

9.47

17.91

15.14

13.10

14.81

8.62

16.44

18.82

20.62

15.98

11.85

13.37

9.31

2.80

1.40

1.07

1.75

2.22

3.62

3.64

3.60

2.57

3.43

3.87

2.41

1.60

2.14

8.79

10.16

10.45

9.35

6.95

5.26

8.90

5.47

2.73

3.04

2.94

2.51

3.76

2.82

5.12

3.56

1.75

3.62

7.96

8.90

3.43

80 ka

3.41

7.90

5.37

5.96

5.82

3.60

6.44

5.06

3.66

4.01

3.86

7.07

8.14

9.03

7.61

5.06

5.08

3.25

0.48

--

0.48

0.84

2.25

2.13

1.37

0.08

4.06

1.29

*"~

4.66

2.98

1.89

1.25

2.05

2.01

2.53

0.88

2.01

0.45

1.77

1.00

0.80

0.32

0.48

--

3.34

2.53

1.21

0.40

4.10

3.10

0.88

0.56

0.48

0.52

1.04

--

~

--

4.06

5.63

7.00

3.38

2.49

0.24

"

20.10

9.95

6.77

9.54

7.52

24.24

20.35

17.07

12.47

11.06

31.51

21.36

10.96

10.76

35.49

36.92

36.81

32.17

23.18

19.14

31.16

20.60

23.79

22.52

19.70

14.80

19.75

14.49

22.07

11.56

4.19

24.29

30.45

29.24

11.01

17.12

34.44

24.39

29.69

30.25

17.93

31.76

22.07

15.45

17.12

18.13

31.51

34.64

34.86

30.86

20.60

18.33

11.51

6.96

7.78

7.79

7.72

7.36

6.80

6.81

7.09

7.82

8.24

6.69

7.45

8.36

8.63

6.18

6.56

7.12

7.16

6.31

6.37

6.31

6.80

7.03

7.21

7.48

7.36

7.62

7.92

8.10

8.35

8.67

6.68

7.11

7.69

8.34

6.31

7.16

8.07

8.08

7.85

7.78

7.53

7.93

8.09

7.95

6.29

6.69

7.25

7.89

7.87

8.00

8.06

8.14

0.79

0.82

0.67

8.38

0.34

0.87

0.90

0.87

0.83

0.79

0.99

0.93

0.79

0.91

0.56

0.54

0.55

0.85

1.07

0.89

1.15

0.96

0.76

0.74

0.70

0.68

0.92

0.72

1.02

0.75

0.37

0.80

1.23

1.37

0.68

0.80

1.61

1.75

1.13

1.05

0.79

1.09

0.91

0.87

1.09

0.87

1.57

1.57

1.29

1.29

1.08

1.04

0.87

__

--

""

_

--

"

__

--

--

--

--

--

--

--

--

--

_

--

""

._

--

--

--

--

--

--

--

--

--

"

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B25
Supplementary Table 3. Extractive chemical analyses Continued

Percentage of <2-mm 

Basal Total Org'anic

No. Sample Hori zon depth

(cm)

N C

Exchange

Na

Exchange 1

K

Al luvium, 80

54

55

56

57

58

59

60

61

62

63

64

65

66

67

V3

V3

V3

V3

V3

V3

V3

V3

V10

V10

V10

V10

V10

V10

All

A12

A31&A32

2B2t

2B31t

3B32t

3Cox

4C2ox

All

A12

Bit

2B21t

3B31t

4B32t

7

25

58

112

147

182

272

280

6

62

88

152

260

300+

4.00

1.66

1.36

0.37

0.17

0.13

0.11

0.08

1.72

0.83

0.42

0.35

0.13

0.09

0.73

0.97

1.01

1.01

0.76

0.83

0.97

1.05

0.70

0.00

1.20

4.93

10.41

7.26

1.63

1.68

1.40

0.57

0.26

0.22

0.22

0.22

1.02

0.56

0.34

0.49

0.49

0.34

meq/JOOg soil 

Exchange Exchange Exchange

Ca

ka

11.64

7.57

7.76

9.22

8.64

8.64

7.57

6.77

6.55

6.09

5.61

7.50

6.14

4.63

Mg

2.18

1.54

2.41

7.01

6.70

6.91

6.02

5.09

2.16

2.63

4.79

8.86

8.55

6.68

H

5.87

4.22

3.38

2.49

1.89

1.73

1.69

1.29

4.30

3.58

2.98

3.62

1.69

2.53

CEC

24.79

15.55

15.76

18.99

16.26

15.55

15.60

12.07

13.43

13.13

14.85

24.80

19.95

16.64

Percentage

pH

1:1 H 2 0

6.14

6.10

6.16

6.72

7.25

7.34

7.36

7.47

5.99

6.30

6.72

6.52

7.24

6.65

Fed

0.87

0.95

1.05

1.54

1.51

1.46

1.43

1.25

0.92

0.99

1.12

1.68

1.66

1.58

of <2-mm

Al d

__

--

--

--

--

_

"*~

Supplementary Table 4. Clay mineralogy

[Analyst: A.L. Walker, U.S. Geological Survey]

Basal

No. Sample Horizon depth Kaolinite Chlorite Vermiculite Illite Montmorillonite 

(cm)

Al 1 uvi urn, 0.7 ka

2 

3

V2 

V2

2C1 

3C2

39 + -- -H60-1- + -- -- -H-

 M- + 

+ ++

Alluvium, 2 ka

9 

10

13 

14

VI 

VI

V6 

V6

A-i-C 

Clca

Clca 

2C2ca

120 + -- -H160 + -n100 + ++ 

115 + -- -n-

 H-+ 

 H-+

 H-+ 

 M- +

Al 1 uvi urn, 40 k a

20 V4 4B32t 141 

29 V5 4B23t 118

Alluvium over Marine Terrace, 80 ka

39 V8 4B22tca 152 

50 V9 4B31t 157

+ -K-K 

 H-+

Alluvium, 80 ka

57 V3 2B2t 112

K, trace constituent ++, minor constituent -H-H, major constituent , not detected

B26 Soil Chronosequences in the Western United States
Supplementary Table 5. Total chemical analyses of the fine (less than 47 vim) fraction by X-ray 

fluorescence

[Zr in parts per million; all others in weight percent. Analysts: J. Baker, J. Budahn, R. Knight, J. Taggert, 

and J.S. Wahlberg]

No.

1 

2 

3

4

5

6

7

9 

10

11

12 

13 

14

16

17

1 Q

19 

20

21 

22

24

o/r

27

29 

30

31

33

35

Sample

V2 

V2 

V2

V7

V7

VI

VI 

VI

VI 

VI

V6

V6 

V6 

V6

V4

V4 

V4

V4

V4 

V4

V4 

V4

V5

V5 

V5

V5

V5

V5 

V5

V5 

V5N

V5N

V5N

Horizon

A 

2C1 

3C2

A12

A12

A+C 

Clca

A12 

Clca 

2C2ca

A12

On O-f

3B3H 

4B32t

5B33t 

7C only

A12

on 1

ODO 1 i

on OOv

4B23t 

5B31-7B33

8C

DO1 4.

D Q

2Clox

Basal 

depth 

(cm)

5 

39 

60+

55

74

17

53

QO

120 

160

60 

100 

115

20

53

QO

115

131

141

158 

310

17

51

60

79

98

106

118 

149

155+ 

23

QQ

100+

Si0 2

56.5 

57.0 

58.2

-54.2

57.7

58.6 

56.9

54.2 

51.9 

51.5

62.5

60.5

61.5 

63.7

60.8

59.2

62.6

A1 2°3

;

14.7 

15.0 

15.1

14.3

14.7

15.0 

14.5

15.2 

14.6 

14.3

14.1

14.5

14.3 

14.0

14.1

15.4

11.8

Fe 2 0 3

Ml uvium, i

5.59 

5.96 

5.62

6.05

Al 1 uvium,

5.82

5.64 

5.03

6.39 

6.08 

5.94

Al luvium,

4.63

6.03

5.55 

4.52

4.57

6.05

1.60

MgO

0.7 ka

2.30 

2.50 

2.40

2.60

2 ka

2.00

2.10 

2.10

2.40 

2.40 

2.50

40 ka

1.30

2.00

2.10 

1.60

1.50

2.20

0.93

CaO Na 2 0

2.80 2.3 

3.13 2.3 

3.38 2.5

2.37 1.8

1.84 2.2

2.90 2.6 

5.38 2.5

2.80 2.3 

6.69 2.1 

7.80 2.2

1.67 2.3

1.90 2.0

1.95 2.2 

2.30 2.8

1.74 2.3

2.00 2.2

8.26 2.7

K2o

2.90 

2.73 

2.70

2.86

2.81

2.66 

2.58

2.88 

2.62 

2.59

1.70

2.01

2.18 

2.22

2.91

2.34

3.44

Ti0 2

0.75 

0.78 

0.79

0.73

0.76

0.78 

0.76

0.78 

0.74 

0.75

0.67

0.72

0.71 

0.65

0.58

0.77

0.23

P 2°5

0.30 

0.30 

0.30

0.54

0.30

0.30 

0.30

0.50 

0.30 

0.30

0.20

0.58

0.57 

0.61

0.20

0.40

0.30

MnO

0.05 

0.05 

0.05

0.04

0.04

0.05 

0.03

0.05 

0.05 

0.04

0.03

0.04

0.03 

0.02

0.04

0.04

0.02

Zr

200 

208 

276

143

211

247 

252

170 

173 

157

208

276

196 

246

159

208

97

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B27
Supplementary Table 5. Total chemical analyses of the fine (less than 47 ym) fraction by X-ray 

fluorescence Continued

No.

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

Sample

V8 

V8 

V8 

V8 

V8 

V8 

V8

V8 

V8 

V8

V9 

V9 

V9 

V9 

V9 

V9 

V9 

V9

V3 

V3 

V3 

V3 

V3 

V3 

V3 

V3

V10 

V10 

V10 

V10 

V10 

V10

Horizon

All 

2A3 only 

3B21t 

4B22tca 

5B31ca 

6B32ca 

7B33ca 

buried? 

8B34ca 

buried? 

9Clca 

buried? 

10C2ca 

buried?

Al 

2A3 

2B21t 

3B22t 

4B31t 

5B32t 

5B33ca 

6Cca

All 

A12 

A31&A32 

2B2t 

2B31t 

3B32t 

3Cox 

4C2ox

All 

A12 

Bit 

2B21t 

3B31t 

4B32t

Basal 

depth 

(cm)

2.5 

54 

90 

152 

183 

190 

200

217 

269 

300

13 

47 

68 

100 

157 

201

311

7 

25 

58 

112 

147 

182 

272 

280

6 

62 

88 

152 

260 

300+

Si02 A1 2 0 3 Fe 2 0 3

Alluvium over Marine

64.1 14.7 4.00

58.1 16.7 6.87

58.4 16.5 6.35

58.5 15.8 5.90 

63.1 14.8 4.34

57.8 16.3 6.83

62.3 15.3 4.88

Al 1 uvi urn,

61.1 14.9 4.68

52.3 19.4 8.16

53.0 18.4 8.61

59.4 15.7 5.81

50.5 18.8 9.22 

52.8 18.0 9.67

MgO CaO Na 2 0 K 2 0 Ti02 P^ MnO

Terrace, 80 ka

1.10 1.56 2.9 2.80 0.85 0.10 0.05

2.40 1.63 2.3 2.51 0.88 0.10 0.03

2.40 1.72 2.5 2.80 0.85 0.20 0.04

2.20 3.27 2.6 2.88 0.84 0.30 0.04 

1.20 1.52 2.9 2.71 0.89 0.10 0.06

2.50 1.66 2.4 2.65 0.87 0.20 0.05

1.80 2.82 3.1 2.85 0.86 0.30 0.04

80 ka

1.20 1.33 2.7 3.06 0.81 0.20 0.07

1.90 0.99 1.5 2.30 0.85 0.10 0.06

2.10 0.93 1.5 2.27 0.78 0.20 0.05

1.40 1.14 2.6 2.75 0.85 0.20 0.05

2.00 0.74 1.9 1.81 0.75 0.30 0.06 

1.90 0.68 2.3 2.11 0.76 0.30 0.13

Zr

352

178

164

402 

235

202

427

283

153

156

303

152 

307

BZ8 Soil Chronosequences in the Western United States
Supplementary Table 6. Total chemical analyses of the less-than-2-mm fraction by X-ray fluorescence

[Zr in parts per million; all others in weight percent. Analysts: A.J. Barter, K. Dennen, R. Johnson, J.R. 

Lindsay, B. Scott, K. Stewart, J. Taggert]

No.

1 

2 

3

4

5

6

7

9 

10

11

12 

13 

14

15

16

17

1 Q

19 

20

21 

22

23 

24

o c

O£

27

9Q

29

30 

31

32

33

34

0 C.

Sample

V2 

V2 

V2

V7 

V7

VI

VI 

VI

VI 

VI

V6

V6 

V6 

V6

V4

V4

V4 

V4

V4 

V4

V4 

V4

V5 

V5

V5

V5 

V5

V5

V5

V5 

V5

V5N

V5N

V5N

V5N

Horizon

A 

2C1 

3C2

A12

A12

A+C 

Clca

A12 

Clca 

2C2ca

A12

3B31t 

4B32t

5B33t 

7C only

A12

tbi

L.DL 11. 

ODOO*

4B23t

8C

QL. It

DO

2Clox

Basal 

depth 

(cm)

5 

39 

60+

55

74

17

53

Q9

120 

160

50

60 

100 

115

20

53

115

131 

141

158 

310

17 

51

60

79

106

118

149 

155+

23

100+

Si0 2

65.2 

68.6 

70.6

80.2

68.8

68.7 

65.0

66.3 

65.9 

64.0

65.6

66.8

63.6 

66.9

71.5

68.1

70.6

Al

12 

12 

12

9

12

12 

13

13 

12 

12

13

13

13 

13

11

12

9

2°3 Fe 2°3

Alluvium,

.3 2.92 

.9 3.06 

.8 2.55

.00 1.26

Al luvium,

.8 3.35

.8 3.12 

.1 3.39

.0 3.50 

.9 3.33 

.8 3.45

Al luvium,

.1 3.69

.0 4.01

.7 4.75 

.3 3.63

.2 2.58

.9 3.64

.83 1.10

MgO

0.7 ka

1.19 

1.21 

0.99

0.48

2 ka

1.11

1.15 

1.39

1.23 

1.18 

1.34

40 ka

1.01

1.30

1.76 

1.25

0.86

1.31

0.59

CaO

2.34 

2.57 

2.33

0.95

1.46

2.07 

4.01

2.13 

3.74 

4.70

1.63

2.12

1.98 

2.35

1.20

1.49

5.95

Na 2 0

2.50 

2.65 

2.77

1.92

2.49

2.60 

2.65

2.45 

2.60 

2.46

2.41

2.63

2.36 

2.84

2.14

2.28

2.30

K2 0

3.03 

3.09 

3.23

2.94

3.09

3.03 

2.92

3.08 

3.07 

3.00

1.89

2.26

2.25 

2.37

2.92

2.79

3.05

Ti02

0.43 

0.49 

0.41

0.20

0.48

0.48 

0.51

0.51 

0.50 

0.47

0.57

0.53

0.62 

0.52

0.37

0.51

0.19

P2°5

0.24 

0.21 

0.18

0.24

0.20

0.21 

0.23

0.34 

0.22 

0.20

0.18

0.71

0.58 

0.64

0.13

0.26

0.23

MnO

0.02 

0.02 

0.02

0.02

0.03

0.03 

0.02

0.04 

0.03 

0.03

0.04

0.03

0.04 

0.03

0.03

0.03

0.03

Zr

186 

177 

198

117

215

239 

207

251 

238 

197

251

220

177 

220

173

213

138

Soils Developed on Coastal and Fluvial Terraces near Ventura, California BZ9
Supplementary Table 6. Total chemical analyses of the less-than-2-mm fraction by X-ray fluorescence Continued

No.

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

Sample

V8 

V8 

V8 

V8 

V8 

V8 

V8

V8 

V8 

V8

V9 

V9 

V9 

V9 

V9 

V9 

V9 

V9

V3 

V3 

V3 

V3 

V3 

V3 

V3 

V3

V10 

V10 

V10 

V10 

V10 

V10

Horizon

All 

2A3 only 

3B21t 

4B22tca 

5B31ca 

6B32ca 

7B33ca 

buried? 

8B34ca 

buried? 

9Clca 

buried? 

10C2ca 

buried?

Al 

2A3 

2B21t 

3B22t 

4B31t 

5B32t 

5B33ca 

6Cca

All 

A12 

A31&A32 

2B2t 

2B31t 

3B32t 

3Cox 

4C2ox

All 

A12 

Bit 

2B21t 

3B31t 

4B32t

Basal 

depth 

(cm)

2.5 

54 

90 

152 

183 

190 

200

217 

269 

300

13 

47 

68 

100 

157 

201 

266 

311

7 

25 

58 

112 

147 

182 

272 

280

6 

62 

88 

152 

260 

300+

Si02 A1 20 3 Fe 20 3

Alluvium over Marine

67.8 13.5 3.08

62.1 15.3 5.33

59.7 16.0 5.77

61.4 14.5 4.78 

67.6 13.3 3.27

61.0 15.6 5.54

66.5 14.2 3.57

Al 1 u vi urn,

70.6 12.5 3.00

68.1 13.5 4.83

73.5 11.7 3.83

68.9 13.7 3.52

66.9 13.9 5.22 

68.9 13.2 4.52

MgO CaO Na 2 0 K2 0

Terrace, 80 ka

0.78 1.42 2.86 2.85

1.82 1.64 2.56 2.55

2.16 1.69 2.43 2.79

1.69 3.62 2.59 2.84 

0.77 1.36 2.78 2.79

2.09 1.65 2.62 2.67

1.31 2.72 3.12 2.93

80 ka

0.70 0.99 2.63 3.03

1.08 0.71 2.05 2.51

0.91 0.64 2.11 2.64

0.84 0.94 2.93 2.87

1.22 0.62 2.41 2.34 

1.04 0.59 2.75 2.40

Ti02 P 2 0 5 MnO Zr

0.65 0.08 0.04 358

0.72 0.13 0.04 223

0.76 0.23 0.04 163

0.68 0.25 0.04 241 

0.65 0.08 0.04 424

0.75 0.22 0.04 194

0.62 0.22 0.03 316

0.51 0.10 0.05 318

0.49 0.09 0.04 161

0.38 0.08 0.02 141

0.56 0.09 0.05 300

0.49 0.17 0.03 154 

0.45 0.14 0.05 177

B30 Soil Chronosequences in the Western United States
Supplementary Table 7, Part 1. Total chemical analyses of the fine (less than 47 ym) fraction by instrumental neutron activation

[K and Fe values in weight percent; all others in part per million. Analysts: J. Rudahn, R. Kntght, and D.M. McKown]

No. Sample Horizon

Basal 

depth 

(cm)

Ba Ce Co Cr Cs Dy Eu Fe Gd Hf K La Lu Mn

Al 1 jvi urn, 0.7 ka

1 

2 

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

V2 

V2 

V2

V7 

V7

VI 

VI 

VI 

VI 

VI

V6 

V6 

V6 

V6

V4 

V4 

V4 

V4 

V4 

V4 

V4 

V4

V5 

V5 

V5 

V5 

V5 

V5 

V5 

V5 

V5

V5N 

V5N 

V5N 

V5N

A 

2C1 

3C2

All 

A12

All 

A12 

A13 

A-i-C 

Clca

All 

A12 

Clca 

2C2ca

All 

A12 

A13 

2B2t 

3B31t 

4B32t 

5B33t 

7C only

All 

A12 

A3 

2B1 

2B21t 

3B22t 

4B23t 

5B31-7B33 

8C

All 

B21t 

B3 

2Clox

5 

39 

60+

55 

74

17 

53 

82 

120 

160

50 

60 

100 

115

20 

53

115 

131 

141 

158 

310

17 

51 

60 

79 

98 

106 

118 

149 

155+

23 

54 

89 

100+

614 

721 

755

632

717

729 

714

616 

586 

578

715

621

642 

667

838

99

1060

76.5 

79.4 

82.5

65.0

71.1

78.5 

69.6

74.1 

76.4 

70.5

62.8

57.5

56.3 

53.8

56.8

69.1

33.1

10.4 

12.8 

11.7

11.5

10.5

11.0 

11.1

12.3 

12.5 

11.4

8.98

8.75

8.12 

6.29

9.47

10.9

4.08

88.3 5.31 

104 6.41 

98.4 5.67

114 6.67

Al luvium,

98.2 5.84

93.8 5.54 

92.3 5.70

91.9 6.17 

87.8 5.75 

83.1 5.38

Al 1 uvi urn,

127 5.29

148 6.28

137 7.54 

122 4.56

108 4.85

126 6.37

64.6 2.10

Alluvium over Marine

36 

37 

38 

39 

40 

41 

42

43 

44 

45

46 

47 

48 

49 

50 

51 

52 

53

V8 

V8 

V8 

V8 

V8 

V8 

V8

V8 

V8 

V8

V9 

V9 

V9 

V9 

V9 

V9 

V9 

V9

All 

2A3 only 

3B21t 

4B22tca 

5B31ca 

6B32ca 

7B33ca 

buried? 

8B34ca 

buried? 

9Clca 

buried? 

10C2ca 

buried?

Al 

2A3 

2B21t 

3B22t 

4B31t 

5B32t 

5B33ca 

6Cca

2.5 

54 

90 

152 

183 

190 

200

217 

269 

300

13 

47 

68 

100 

157 

201 

266 

311

752

609

740

692 

718

645

692

81.8

80.6

79.6

82.1 

82.9

83.3

83.4

10.6

10.7

11.9

11.6 

10.9

11.1

9.27

74.1 4.39

91.2 7.11

88.2 7.36

84.6 6.17 

73.9 4.43

84.2 7.08

83.6 4.62

5.63 

5.66 

5.45

4.68

2 ka

5.30

6.07 

5.08

5.36 

5.50 

5.11

40 ka

5.50

4.80

4.60 

4.30

4.40

5.50

2.54

Terrace

5.77

6.91

5.38

5.67 

6.19

7.11

6.31

1.37 

1.38 

1.38

1.13

1.38

1.36 

1.25

1.31 

1.37 

1.29

1.32

1.13

1.14 

1.04

1.17

1.32

0.722

, 80 ka

1.46

1.77

1.49

1.47 

1.45

1.63

1.44

3.56 5.85 

4.35 5.93 

4.04 5.95

4.32 4.50

4.17 6.15

3.88 6.07 

3.86 5.11

4.47 5.44 

4.35 6.1 

4.020 

3.19 5.95

4.08 5.20

3.89 5.00 

3.02 4.50

3.20 4.5

4.12 5.51

1.19 2.80

2.80 5.83

4.80 7.10

4.45 5.98

4.14 6.54 

2.80 

4.32 

3.17 

5.96 

5.24 

6.36

3.36

4.78

5.99 

4.64

3.96 

4.14 

3.79

5.29

5.35

4.04 

5.91

3.56

4.67

2.07

9.47

4.34

3.82

6.10 

9.61

4.56

10.6

2.27 

2.27 

2.17

2.51

2.41

2.33 

2.31

2.48 

2.50 

2.22

1.51

1.76

2.03 

1.91

2.53

1.95

3.13

2.45

2.23

2.42

2.49 

2.15

2.21

2.22

40.2 

41.2 

42.2

33.0

38.8

40.5 

36.6

39.1 

39.4 

37.7

33.4

32.4

33.5 

29.1

30.9

36.8

17.7

40.6

47.4

43.0

41.6 

43.5

47.2

43.7

0.462 

0.450 

0.476

0.365

0.454

0.478 

0.394

0.430 

0.420 

0.397

0.460

0.400

0.400 

0.385

0.363

0.490

0.205

0.514

0.535

0.442

0.464 

0.555

0.567

0.548

369 

455 

427

427

420

448 

430

451 

449 

417

352

381

326 

252

416

422 

268

461 

346 

400

416 

496

398 

388

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B31
Supplementary Table 7, Part 1. Total chemical analyses of the fine (less than 47 um) fraction by instrumental neutron activation Continued

No.

54

55 

56

57

CO

59

60

61

c o

63 

64

65

66

67

Sample

V3

V3 

V3

V3

V3

V3

V3

V3 

V10

V10 

V10

V10

V10

V10

Horizon

A12

ATI IATO

2B2t

ODQ i f

QDQOf

4C2ox

A12

B1 ¥

3B31t

4B32t

Basal

depth

(cm)

7

25

CQ

112

147

1 QO

272

280 

6

62

00

152

260

300-K

Ba

797

753

757

788

1380

1070

Ce Co

81.6 10.3

83.0 9.07

110 9.84

91.8 7.73

183 9.64

255 35.40

Cr Cs

Al 1 uvium,

78.8 5.11

96.7 7.04

110 7.72

82.5 4.78

106 5.40

99.9 5.22

oy

80 ka

5.69

4.73

10.3

6.47

13.9

20.3

Eu Fe Gd Hf K La Lu Mn

1.37 3.27 5.51 6.76 2.52 42.6 0.475 597

1.27 5.77 5.45 3.72 1.93 46.9 0.389 413

2.86 5.92 12.1 3.25 2.19 60.5 0.630 493

1.58 3.85 7.13 2.30 49.9 0.505 464

3.79 6.00 -- 3.24 1.58 97.0 0.800 494

5.28 6.42 3.79 1.81 139.0 1.220 983

Supplementary Table 7, Part 2. Total chemical analyses of the fine (less than 47 ym) fraction by instrumental neutron 

activation

[Na value in weight percent; all others in part per million. Analysts: J. Rudahn, R. Knight, and D.M. McKown]

No. Sampl e Hori zon

Basal

depth

(cm)

Na Nd Rb Sb Sc

Al 1 uvi urn,

1

2

3

4

5

6

7>

8

9

10

11

12

13

14

V2

V2

V2

V7

V7

VI

VI

VI

VI

VI

V6

V6

V6

V6

A

2C1

3C2

All

A12

All

A12

A13

A-i-C

Clca

All

A12

Clca

2C2ca

5

39

60+.

55

74

17

53

82

120

160

50

60

100

115

1.94

1.74

1.83

_ _

1.47

1.61

1.86

1.77

__

1.60

1.60

U67

35.9

38.6

36.1

__

29.0

37.4

35.8

33.8

__

33.1

36.1

31.1

108

118

113

__

121

117

109

109

._

120

110

101

1.15

1.77

1.36

__

0.962

1.17

--

1.32

1.51

__

1.31

1.25

1.08

12.0

13.8

13.3

..

14.5

Al 1 uvi urn,

13.3

12.8

12.2

__

14.2

13.5

12.7

Sin

0.7 ka

6.77

7.05

6.96

..

5.73

2 ka

6.71

--

6.96

6.17

._

6.51

6.8

6.38

Sr

298

258

246

__

206

191

--

225

253

._

217

261

262

Ta

1.17

1.17

1.17

__

1.08

1.09

1.20

1.06

..

1.10

1.10

1.04

Tb

0.868

0.900

0.886

--

0.746

0.894

0.912

0.807

..

0.859

0.889

0.832

Th

13.2

14.1

14.2

__

12.4

13.4

--

13.4

12.4

__

13.6

13.5

12.6

Tm

0.500

0.500

0.480

__

0.390

0.510

--

0.510

..

0.470

0.480

0.420

U

4.04

5.57

5.20

__

4.90

3.99

--

3.89

4.13

..

3.23

3.22

3.34

Yb

3.03

3.07

2.92

__

2.38

3.01

--

3.10

2.77

._

2.72

2.68

2.58

Zr

218

177

255

__

119

180

--

239

170

__

148

160

127

B3Z Soil Chronosequences in the Western United States
Supplementary Table 7, Part Z. Total chemical analyses of the fine (less than 47 ym) fraction by instrumental neutron 

activation Continued

No.

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

Sample

V4

V4

V4

V4

V4

V4

V4

V4

V5

V5

V5

V5

V5

V5

V5

V5

V5

V5N

V5N

V5N

V5N

Hori zon

All

A12

A13

2B2t

3B31t

4B32t

5B33t

7C only

All

A12

A3

2B1

2821t

3B22t

4B23t

5B31-7B33

8C

All

B21t

B3

2Clox

Basal

depth

(cm)

20

53

83

115

131

141

158

310

17

51

60

79

98

106

118

149

155+

23

54

89

100+

Na

..

1.79

--

1.58

1.73

2.06

__

1.80

1.59

2.07

__

Nd

30.6

--

28.9

28.7

24.2

__

29.6

--

34.4

16.1

__

--

--

Rb

..

81.3

93.5

91.7

84.4

__

105

--

96.5

93.7

__

Sb

1.32

--

1.34

1.46

1.19

__

1.09

--

1.64

--

0.659

__

--

Sc

Al 1 uvi urn,

11.2

--

13.2

13.4

10.1

__

10.9

_-

--

13.9

4.44

__

Alluvium over Marine

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

V8

V8

V8

V8

V8

V8

V8

V8

V8

V8

V9

V9

V9

V9

V9

V9

V9

V9

V3

V3

V3

V3

V3

V3

V3

V3

V10

V10

V10

V10

V10

V10

All

2A3 only

3B21t

4B22tca

5B31ca

6B32ca

7B33ca

buried?

8B34ca

buried?

9Clca

buried?

10C2ca

buried?

Al

2A3

2B21t

3B22t

4B31t

5B32t

5B33ca

6Cca

All

A12

A31&A32

2B2t

2B31t

3B32t

3Cox

4C2ox

All

A12

Bit

2B21t

3B31t

4B32t

2.5

54

90

152

183

190

200

217

269

300

13

47

68

100

157

201

266

311

7

25

58

112

147

182

272

280

6

62

88

152

260

300+

2.29

--

--

1.76

1.80

1.97

2.13

--

1.79

2.28

1.95

1.16

--

..

1.13

..

1.97

..

1.38

1.72

37.4

--

46.8

--

37.7

37.5

38.5

--

42.1

--

37.1

37.8

--

37.7

68.8

__

42.0

88.4

118

112

--

112

123

,-

127

107

..

116

106

..

134

107

--

125

115

94.8

97.8

0.988

-.

1.30

--

1.13

--

1.12

1.00

-.

1.03

0.865

0.948

1.37

1.30

__

1.04

-.

1.24

1.30

10.4

--

--

15.3

--

15.0

--

13.5

10.2

--

..

14.4

11.0

Al 1 uvi urn,

11.5

17.3

18.2

 _

12.8

--

19.3

17.5

Sm

40 ka

6.25

--

5.61

5.75

5.05

__

5.56

_-

--

6.71

3.07

__

--

Terrace

7.04

--

--

8.58

--

7.58

7.2

6.95

--

8.1

6.87

80 ka

6.92

6.67

--

..

14.2

__

7.7

17.9

22.6

Sr

218

--

195

--

215

218

__

204

--

198

.-

307

__

..

--

, 80 ka

260

188

207

--

--

225

242

215

251

182

110

170

__

213

131

150

Ta

0.970

--

--

0.962

--

0.966

0.916

._

0.914

--

1.09

0.460

__

--

1.33

1.20

1.22

1.25

1.28

--

1.21

1.21

..

1.34

1.22

--

1.04

__

1.27

0.920

1.04

Tb

..

0.893

0.760

0.783

0.699

._

0.701

--

--

0.880

0.421

_.

--

--

0.954

--

1.13

--

--

0.959

0.955

0.963

--

1.11

--

0.993

0.899

0.790

1.77

1.04

2.31

3.40

Th

..

10.9

11.8

--

11.0

9.85

__

10.3

--

12.9

5.01

__

--

12.7

--

15.0

14.4

14.3

13.1

--

14.4

--

13.9

13.1

16.5

--

14.7

14.5

18.3

18.0

Tm U

..

0.534 6.29

_.

0.420 5.81

0.470 5.61

0.410 4.48

_.

0.370 3.00

..

0.480 3.88

0.239 2.39

__

..

--

0.590 3.92

..

_.

0.567 3.48

._

0.490 3.44

_-

0.540 3.62

3.99

._

3.48

3.62

0.510 4.87

0.420 4.29

0.736 4.15

_-

4.25

4.20

4.08

Yb

2.96

--

2.49

2.57

2.49

__

2.41

3.06

--

1.35

__

--

 

3.48

3.52

2.89

3.05

3.41

3.39

3.49

__

2.99

2.51

4.33

__

3.23

5.44

8.11

Zr

..

182

164

--

120

215

_

154

174

84.4

__

333

154

143

224

357

168

425

__

247

156

149

__

270

174

239

Soils Developed on Coastal and Fluvial Terraces near Ventura, California B33
Supplementary Table 8. Methods used in laboratory analyses

Analysis Method Most recent references

Sample preparation - Crushing, sieving,

sonication.

Particle sizeBulk densityExchangeable cations 

(cation-exchange 

capacity).

Total acidity-- 

Total N 

Organic carbonOithionite-extractable 

Al and Fe.

Oxalate-extractable 

Al and Fe.

Clay mineralogy- - 

X-ray fluorescenceInstrumental neutron 

activation.

Sieving, pipetClodBaClBusacca and Singer 

(1984), Singer and 

Janitzky (in press).

Singer and Janitzky (in 

press).

Do. 

Do.

BaCl-triethanolamine- Do. 

Kjeldahl Do. 

Walkley-Black Do.

Citrate-bicarbonate- Do. 

dithionite.

Sodium oxalate --- Walker (1984). 

Glycolation, heating- - - - 

B34 Soil Chronosequences in the Western United States

GPO 785-048/48014