Weathering Rinds on Andesitic and

asaltic Sones as a

Quaternary Age Indicator,

estern United States
Weathering Rinds on Andesitic and 

Basaltic Stones as a 

Quaternary Age Indicator, 

Western United States

By STEVEN M. COLMAN 

and KENNETH L. PIERCE

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1210

Weathering rinds can effectively differentiate 

Quaternary deposits according to relative age and, with 

calibration, can be used to estimate numerical ages

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1981
UNITED STATES DEPARTMENT OF THE INTERIOR 

JAMES G. WATT, Secretary

GEOLOGICAL SURVEY 

H. William Menard, Director

Library of Congress Cataloging in Publication Data

Colman, Steven M.

Weathering rinds on andesitic and basaltic stones as a Quaternary age indicator, Western United States.

(Geological Survey Professional Paper 1210)

Bibliography: p. 39

Supt. of Docs, no.: I 19.16:1210

1. Geology, Stratigraphic-Qua ternary. 2. Weathering-The West. 3. Andesite-The West. 4. Basalt-The West.

I. Pierce, Kenneth Lee, joint author. II. Title. III. Series: United States Geological Survey Professional Paper 1210.

QE696.C656 551.7r9'0978 80-607840

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402
CONTENTS

Abstract 

Introduction 

Purpose 

Previous work

Acknowledgments 

General description of weathering rinds on andesitic and

basaltic stones 

Factors affecting weathering-rind thickness 

Sampling design and methods 

Structure of the data 

Areas and types of deposits sampled 

Sample site selection 

Sample collection

Measurement procedures 

Environmental factors other than time Topographic position 

Parent material 

Vegetation 

Climate 

Summary 

The relation between weathering-rind development and time Weathering rinds as an indicator of relative age 

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Weathering-rind development and time Continued 

Statistical analysis

Nature of the weathering-rind measurement distributions - 

Analysis of variance 

Multiple comparisons 

Summary of statistical analysis 

Numerical model of weathering-rind development with 

time _ 

Rind-thickness ratios 

Time-stratigraphic nomenclature 

Rate curves for weathering-rind thickness 

Regional correlations based on ages estimated from weathering rinds 

Cascade Range-Puget Lowland 

California Mountains 

Rocky Mountains 

Summary 

References cited 

Appendix A. Weathering-rind thickness measurements 

Appendix B. Sample locations and site data 

Appendix C. Generalized petrographic descriptions

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ILLUSTRATIONS

FIGURE 1. Photographs showing examples of weathering rinds on andesitic rocks near Lassen Peak, Calif 

2. Photographs showing examples of weathering rinds on basaltic rocks near McCall, Idaho 

3. Index map of sampling localities, Western United States 

4. Photograph showing destruction of weathering rinds on stones brought to the surface of Tahoe Till near Lassen 

Peak, Calif ___ 

5. Diagram showing interrelations among factors affecting weathering-rind development 

6-9. Graphs showing:

6. Rind thickness versus mean annual precipitation

7. Average weathering-rind thicknesses on fine-grained andesite against coarse-grained andesite from same 

sampling sites 

8. Average weathering-rind thicknesses on stones from outwash against those from till, with age, rock type, 

and sampling area held constant 

9. Average weathering-rind thicknesses on stones from sites with grass and (or) sage vegetation against those 

from sites with forest vegetation 

10. Graphs of elevation, mean annual precipitation, and weathering-rind measurements along the Bullfrog terrace,

Yakima Valley ~ 

11-13. Diagrams showing:

11. Weathering-rind measurements on basalt -

12. Weathering-rind measurements on andesite -

13. Average weathering-rind thicknesses for the sequence of tills and terraces recognized in each of the principal 

sampling areas 

14. Graph of reproducibility of weathering-rind measurements

15. Selected histograms of weathering-rind measurements

16. Diagrammatic sketch of the nested sampling design for the deposits near McCall, Idaho 

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in
IV CONTENTS

Page

FIGURE 17-19. Graphs showing:

17. Weathering-rind thickness versus time curves for Bohemia and West Yellowstone 26

18. Conceptual models of the weathering-rind thickness versus time function 27

19. Weathering-rind thickness versus time curves for each of the principal sampling areas 30

20. Chart comparing ages estimated from weathering rinds in glacial deposits in this study with the deep-sea oxygenisotope record - 32

21. Correlation chart for deposits sampled in this study - 33

TABLES

TABLE 1. Average weathering-rind thicknesses - 18

2. Skewness and kurtosis for weathering-rind thickness distributions 20

3. Analysis of variance, McCall and Lassen Peak data - 22

4. Summary of results of Scheffe's multiple comparison test 23

5. Rind-thickness ratios - 25

6. Characteristics of deposits considered to be about 140,000 yr old (oxygen-isotope stage 6) 28

7. Deposits used as calibration points, and derivation of the rate factors used in the weathering-rind equation

 

 

n \r\o l(\ T\ I* 1U{2 \"' ' "
WEATHERING RINDS ON ANDESITIC AND BASALTIC STONES

AS A QUATERNARY AGE INDICATOR,

WESTERN UNITED STATES

By STEVEN M. COLMAN and KENNETH L. PIERCE

ABSTRACT

Approximately 7,335 weathering rinds were measured on basaltic 

and andesitic stones in Quaternary glacial deposits to assess the use 

of weathering rinds as a relative- and numerical-age indicator. These 

rinds were studied at 150 sites in 17 different areas of the Western 

United States. Sampling methods were designed to limit the variability of environmental factors other than time (climate, vegetation and 

other organisms, parent material, and topography) that affect rind 

development. Only andesitic or basaltic lithologies were sampled, and 

sampling sites were restricted to terraces or flat moraine crests in 

areas that differ only moderately in climate. Within the restrictions of 

these sampling procedures, variation in rock types among sampling 

areas appears to be the most important factor, other than time, that 

affects weathering-rind development. Differences in climate among 

sampling areas also have a major effect, whereas the influence of such 

factors as vegetation, topography, and soil-matrix texture appears to 

be comparatively minor.

Statistical analysis demonstrates that weathering rinds are an excellent quantitative indicator of age. Within a sampling area, deposit 

age is the most important source of variation in rind thickness, and all 

differences in mean rind thickness between deposits of different 

stratigraphic ages are important.

Rind-thickness data for independently dated deposits near West 

Yellowstone, Mont, and elsewhere demonstrate that the rate of increase in weathering-rind thickness decreases with time. Because the 

rate decreases with time, the ratio of the rind thicknesses of two 

deposits in the same area provides a minimum estimate of the 

numerical-age ratio of the two deposits. Based on the West 

Yellowstone sequence, a logarithmic function appears to best represent the relation between weathering-rind thickness and time. 

However, because of the effects of climate and rock type on rind 

development, a logarithmic time-function must be calibrated for each 

sampling area. Because of the absence of independent numerical-age 

estimates in areas other than West Yellowstone, the age of one 

deposit (with rinds >0.5 mm thick) in each area was inferred by correlations based on stratigraphy and relative-age criteria. The inferred 

age of this one deposit in each area was then used as the calibration 

point for the rind-thickness curve for that area. The ages of the other 

deposits in each area were estimated from their rind thickness and 

the calibrated weathering-rind curves.

Ages estimated from weathering-rind thicknesses and the resulting 

conclusions depend on several assumptions and inferences, but the 

data clearly suggest that, if the rate equations can be calibrated, 

weathering rinds can be used to approximate numerical ages, perhaps 

to within 10-20 percent. In addition, age estimates based on weathering rinds provide quantitative comparisons that constrain regional

correlations. In the areas examined, ages of glacial deposits estimated 

by these methods appear to group into at least four time intervals: 

about 12,000-22,000, about 35,000-50,000, about 60,000-70,000, 

about 135,000-145,000 yr ago, and possibly several older time 

periods. These time intervals are approximately coeval with times of 

high worldwide ice volume indicated by marine oxygen-isotope 

records. The ages also indicate that several separate ice advances occurred during the Wisconsin Glaciation in the Western United States, 

including both a mid-Wisconsin advance and an early Wisconsin advance in several areas. None of the age estimates for end moraines in 

our sample areas fall between 75,000 and 130,000 yr ago. End 

moraines of a given age are not present in all areas and the number of 

end-moraine ages differs from area to area, probably because of differences in glacier response to local climatic variations.

INTRODUCTION

This study was prompted primarily by the need for 

better dating and correlation of Quaternary deposits in 

the Western United States. The paucity of material 

suitable for dating these deposits by available 

numerical1 (mostly radiometric) methods has persistently hampered regional correlations. In most 

cases, inferences concerning ages have been drawn and 

correlations proposed for these deposits on the basis of 

the extent of weathering and of modification of morphology. However, weathering and erosion processes 

provide only a measure of relative age, because (1) their 

results as functions of time are imperfectly understood, 

(2) difficulties arise in the quantification of their results, 

and (3) their rates are controlled by several environmental factors. Correlations based on relative ages are tentative at best, because rates of weathering and erosion 

can vary significantly, both over short distances and 

with small variations in parent material. In addition, 

relative-age differences do not indicate the magnitude 

of absolute-age differences.

'Throughout this report we will use the term "numerical" for dating techniques that produce age estimates on a ratio scale of years, and "relative-age" for those which produce ages 

on an ordinal scale. (See Griffiths, 1967, p. 245-249, for a discussion of different types of 

scales.) We resist using the term "absolute" for any dating technique.
WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

These difficulties emphasize the need for, and the 

usefulness of, a numerical dating method based on a 

commonly applicable weathering parameter; previous 

studies have shown that weathering rinds on andesitic 

and basaltic stones have some potential for use in such 

a technique. The advantages of weathering rinds over 

the plethora of other time-dependent weathering and 

erosional features result from the potential for isolating 

a single weathering parameter, for objectively measuring that parameter, and for controlling the variables 

that affect it. For these reasons, weathering rinds may 

be a more consistent and representative measure of age 

than other weathering and erosional features for ages of 

104 to 105 yr.

Weathering rinds were measured on andesitic and 

basaltic stones in this study because of certain advantages that result from the fine grain size and mafic composition of these lithologies, for example: (1) a tendency 

for matrix and grain-by-grain alteration rather than intergranular staining, resulting in a relatively consistent 

thickness of weathered material and a well-defined 

"weathering front" (inner boundary of weathering); (2) 

a disinclination for granular disintegration, which often 

destroys rinds on coarser grained rocks; and (3) a 

relatively fast rate of weathering compared to that of 

more felsic rocks of similar grain size.

PURPOSE

This study examines the development of weathering 

rinds on andesitic and basaltic stones with time, with 

the goal of using weathering rinds as a dating method 

for Quaternary deposits in the Western United States. 

In order to accomplish this goal, the influence of 

variables other than time (sampling and environmental 

variables) on rind development must be evaluated. The 

study of weathering rinds as a dating technique will 

begin with their use as a relative-age criterion for local 

sequences of deposits, followed by the use of weathering-rind thickness as an approximate numerical-age 

indicator and regional correlation tool.

PREVIOUS WORK

A number of workers have used weathering rinds on 

andesite and basalt as a relative-age indicator in local 

areas in the Western United States (Crandell, 1963, 

1972; Crandell and Miller, 1974; Birkeland, 1964; Carrara and Andrews, 1975; Kane, 1975; Porter, 1975, 

1976; and Scott, 1977). Each of these local studies 

proved weathering rinds to be a highly effective tool for 

separating deposits of different ages. In particular, 

Porter (1975) was able to demonstrate that weathering 

rinds in the Yakima Valley, Wash., were statistically

consistent for deposits of one age, and significantly different for deposits of different ages. He did not define a 

numerical function for the change in weathering-rind 

thickness with time, because of a lack of independent 

dates for calibration. However, he did suggest that the 

rate of rind formation may decrease with time.

Weathering rinds on other types of rocks have also 

been examined for their use as potential age indicators. 

Obsidian hydration, which produces rinds by hydration 

rather than by the oxidation-hydrolysis processes 

predominating in the rinds examined in this study 

(Colman, 1977), has been used to study Quaternary 

deposits and found to be an effective numerical dating 

technique (Friedman and Smith, 1960; Pierce and 

others, 1976). A number of workers, including 

Birkeland (1973), Benedict (1973), Carroll (1974), Thorn 

(1975), and Burke and Birkeland (1979), among others, 

have studied weathering rinds on granitic rocks and 

demonstrated that they can be useful relative-age indicators. Weathering rinds on granitic rocks are, 

however, subject to problems associated with intergranular staining and granular disintegration.

Desert varnish is a rind-like feature, but detailed 

chemical studies (Engel and Sharp, 1958; Hooke and 

others, 1969) have demonstrated that desert varnish is 

largely a surface coating, due at least in some cases to 

accretion of Fe- and Mn-bound clay (Potter and 

Rossman, 1977). Although desert varnish generally is 

developed to a greater degree with deposit age in a 

given area, large variations in rate of development exist, and local measurements are commonly inconsistent. Consequently, desert varnish has been used only as 

a relative-age inolicator (Hunt and Mabey, 1966).

ACKNOWLEDGMENTS

The writers would especially like to thank D. R. 

Crandell, S. C. Porter, and P. W. Birkeland, who were 

helpful in discussing problems and in locating sampling sites in areas they had mapped. Valuable comments on an early version of the manuscript were provided by D. R. Crandell, R. F. Madole, and D. W. 

Moore. Thanks are also due to the members of Colman's doctoral committee at the University of Colorado, including P. W. Birkeland (chairman) and 

T. R. Walker, who critically reviewed early reports of 

the study, and J. T. Andrews, R. L. Barry, W. C. 

Bradley, E. E. Larson, and D. D. Runnels. W. E. Scott, 

R. M. Burke, and R. R. Shroba provided unpublished 

data and many useful hours of discussion. J. O. Kork 

and A. T. Miesch provided advice on statistical problems. M. S. Colman and L. W. Pierce helped with field 

logistics.
WEATHERING-RINDS ON ANDESITIC AND BASALTIC STONES

GENERAL DESCRIPTION OF

WEATHERING RINDS ON 

ANDESITIC AND BASALTIC STONES

A weathering rind is defined for the purposes of this 

study as a zone of oxidation colors whose inner boundary approximately parallels the outer surface of a stone 

(figs. 1, 2). Other weathering reactions commonly accompany oxidation (Colman, 1977), but the rinds 

measured were defined primarily by visible discoloration. The original gray to black color of the rock is

altered to colors ranging from buff through yellow to 

reddish (2.5 Y to 1.5YR hues). The coloring of some 

weathering rinds is layered; but vague, diffuse inner 

parts of rinds were not measured. These "inner rinds" 

(fig. 2D) are usually dark reddish gray and are usually 

many millimeters thick, but they vary considerably in 

thickness around a single stone and are only displayed 

by some stones. Thin sections of the "inner rinds" 

show that they are usually products of alteration of 

olivine and (or) glass. The kind of alteration that produces the "inner rinds" and the reason for their large

FIGURE 1. Examples of weathering rinds on andesitic rocks near Lassen Peak, Calif. Sampling sites for each deposit are given in Appendixes 

A and B. Arrow or dashed line, areas where true rind thickness is shown. Apparent variation in rind thickness is mostly a function of 

camera angle and unevenness of the broken surface. A, from Tioga Till (about 0.1 mm); B, from "early Tioga" (Kane, 1975) till (about 

0.4 mm); C, from Tahoe Till (about 0.8 mm); D, from pre-Tahoe till (about 2.0 mm).
WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

e

FIGURE 2. Examples of weathering rinds on basaltic rocks near McCall, Idaho. Sampling sites for each deposit are given in Appendixes A and 

B. Arrow, area where true rind thickness is shown. Apparent variation in rind thickness is mostly a function of camera angle and unevenness of the broken surface. A, from Pinedale Till (about 0.3 mm); B, from Intermediate till (about 0.8 mm); C, from Bull Lake Till (about 

1.8 mm); D, example of an inner rind, from Bull Lake Till.

variation are not known, but in many cases deuteric 

alteration along joints and subsequent differential erosion appear likely.

The hardness of weathering rinds varies from almost 

that of the unaltered rock to extremely soft and mushy. 

Weathering-rind hardness appears to decrease with 

time, and rinds from older deposits can often be sliced 

with a knife, smeared with the fingers, or crushed 

where hit with a hammer.

FACTORS AFFECTING WEATHERINGRIND THICKNESS

A large number of variables or factors potentially affect weathering-rind thickness. These factors can be 

classed into two general groups, which here will be 

called sampling factors and environmental factors. 

Elements of the sampling procedure that are capable of 

introducing variation into the measurement of weather-
FACTORS EFFECTING WEATHERING-RIND THICKNESS

ing rinds include (1) selection of sampling sites, (2) collection of samples from sampling sites, (3) procedures 

for measuring the selected samples, and (4) the operator 

who performs the sampling and measuring. Possible 

variation in rind thickness introduced by these factors 

was largely eliminated from this study by using a standard set of sampling and measuring procedures, which 

will be described in the next section. The effect of different operators will be partially evaluated in the 

statistical analysis section.

Environmental factors that affect weathering-rind 

thickness are essentially identical to those postulated 

by Jenny (1941) as the factors in soil formation: 

climate, parent material, vegetation, topography, and 

time. Jackson and Sherman (1953, p. 241-248) have 

stated that the factors that control chemical weathering are essentially those that control soil development. 

Many of these factors are composed of several subvariables. Topography includes the effects of erosion 

and deposition; climate includes temperature, precipitation, and their seasonal distribution; parent material includes rock type, rock texture, and soil matrix texture.

Because the purpose of this study was to examine the 

relationship between weathering-rind thickness and 

time, we attempted to minimize the variation in other 

factors by sampling them over a restricted range. For 

example, out of the wide range of possible lithologies, 

only basaltic and andesitic stones were sampled. 

However, variables other than time could not be completely eliminated, and as a result, we attempted to 

evaluate the effect of residual variation in environmental factors. To a large extent, the effect of time could be 

isolated from the effect of other variables. The evaluation of variables other than time will follow the discussion of sampling procedures.

SAMPLING DESIGN AND METHODS

STRUCTURE OF THE DATA

The basic organization of data in this study is a 

nested, multi-level sampling design. This design consists of the following levels:

1. seven different sampling areas,

2. several stratigraphic ages of deposits within each 

sampling area,

3. several landforms (moraines, terraces) of each age,

4. several sampling sites on each landform,

5. many measurements at each sampling site.

In some areas, the landform level was not used.

The sampling design used in this study was conceived primarily to evaluate the relation between 

weathering-rind thickness and time (age). Age is 

therefore isolated on the second level of the nested 

sampling design. Variation in two important factors in 

rind development, rock type and climate, occurs mostly 

between sampling areas, so that these factors can be 

held nearly constant by analyzing each sampling area 

separately.

The influence of factors other than time on weathering-rind thickness was investigated using several different subsets of the rind thickness data. Some of these 

subsets are part of the data collected for the basic 

nested sampling design; other subsets were collected 

specifically to evaluate the influence of factors other 

than time. For example, the influence of climate was 

evaluated by comparing rind thicknesses on similar 

rock types in deposits thought to be about the same age 

in different sampling areas. However, the rock types 

were not identical, and the ages of the deposits are not 

known with absolute certainty. Therefore, the influences of rock type and climate are to some extent 

"confounded," that is, their influences cannot be completely separated. Such evaluations of the influence of 

each factor are tempered by the amount of confounding 

in the data.

Another subset of data used to evaluate the influence 

of factors other than time was data collected with the 

specific purpose of isolating one of these factors. For 

example, in some cases, a single deposit, such as an outwash terrace, could be traced along a considerable 

climatic gradient. By sampling a single rock type at 

places on the deposit with different climates, rock type 

and age were held constant, and the influence of climate 

could be evaluated independently. Because we attempted to keep variables such as rock type and climate 

relatively uniform within each sampling area in order to 

evaluate the influence of age, much of the data collected 

to specifically isolate other variables was not used in 

the nested sampling structure. Only sites where 

variables such as rock type and climate are relatively 

uniform were used to evaluate the influence of age.

The basic data collected in this study are contained in 

Appendixes A and B. Appendix A provides the mean1 ,

'Mean = X = EXj/n, where X,- are individual observations, and n is 

the number of observations.
WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

standard deviation2 , and number of measurements at 

each site, along with the deposit and rock type on which 

rinds were measured. Appendix B gives site locations 

and other site data.

AREAS AND TYPES OF DEPOSITS SAMPLED

Approximately 7,335 weathering rinds were 

measured at about 150 sites in 17 different areas in the 

Western United States. Most of the deposits sampled 

were either glacial or glaciofluvial because of the 

possibility of correlating deposits resulting from largescale climatic fluctuations, and because of the 

possibility of correlating these deposits with dated 

paleoclimatic records. However, data collection was 

concentrated in seven areas because they contained 

well-developed sequences of deposits of different ages, 

because they contained abundant, relatively uniform 

rock types, and because they had climates conducive 

to rind formation. The stratigraphic ages of deposits 

sampled in each of the seven areas were defined by 

mapping of previous workers (fig. 3). These areas are 

(1) near West Yellowstone, Mont.; (2) near McCall, 

Idaho; (3) the Yakima Valley near Cle Elum, Wash.; (4) 

the Mount Rainier area, Washington; (5) the Satsop 

River drainage and adjacent parts of the Chehalis 

River Valley, Wash., here referred to as the Puget 

Lowland; (6) the Lassen Peak area, California; and (7) 

near Truckee, Calif. The locations and data for the 

other sampling areas are given in Appendixes A and B. 

These areas proved relatively less suitable either 

because of the scarcity of basalts or andesites, because 

of the large variability in these lithologies (especially 

andesites), or because of very dry climates.

SAMPLE SITE SELECTION

Land surface stability was the primary criterion for 

selecting sampling sites, and evidence of erosional or 

depositional disturbance of the weathering profile was 

minimal at most sites chosen. Sampling sites were 

commonly located on relatively flat moraine crests or 

on flat terrace surfaces. This type of site precludes 

burial by colluvium; sites with thick eolian mantles 

were also avoided. These sites were not chosen by formal random selection procedures from all possible sites 

of the above description because of access considerations. However, we are aware of no bias in the selection 

of sample sites, and the selected sites are thought to be 

representative.

2Standard deviation = s =( n 1

110° 105°

.YAKIMA 

VALLEY 

MOUNT 

AINIER

40'

FIGURE 3. Index of sampling localities, Western United States. 

Triangle, principal sampling area Solid dot, secondary sampling 

locality. References to the surficial mapping on which the sampling 

was based are as follows: West Yellowstone, Mont. (Alden, 1953; 

Richmond, 1964, 1976; Pierce, 1973; Waldrop, 1975; Waldrop and 

Pierce, 1975; Pierce and others, 1976); McCall, Idaho (Schmidt and 

Mackin, 1970); Yakima Valley, Wash. (Porter, 1969, 1976); Mt. 

Rainier, Wash. (Crandell and Miller, 1974); Puget Lowland, Wash. 

(Carson, 1970); Lassen Peak, Calif. (Crandell, 1972; Kane, 1975); 

Truckee, Calif. (Birkeland, 1964).

SAMPLE COLLECTION

Several options existed in procedures for selecting 

the stones at each sampling site; these options included the type of stones selected and the position in 

the weathering profile from which the samples were 

taken.

In this study, stones were collected from the soil profile at depths of about 20-50 cm, usually from the 

upper part of the B horizon, or, if a B horizon was not 

present, from the uppermost C (Cox) horizon. All 

stones encountered in the soil profile at the proper 

depth were removed and broken with a rock hammer. 

A preliminary reconnaissance of the rock types present 

in the deposits of a given sampling area formed the 

basis for selection of the lithologies on which rinds 

were measured. These lithologies are those that were 

commori throughout a given sampling area, and that 

were relatively consistent in appearance from site to 

site. All stones of these lithologies encountered at each 

sampling site were retained for measuring rind thickness. Appendix C contains generalized petrographic 

descriptions of the lithologies used in this study in 

each of the principal sampling areas.

The upper part of the B horizon (or the Cox horizon if 

a B horizon was not present) was used as the sampling
FACTORS EFFECTING WEATHERING-RIND THICKNESS

horizon, because the B horizon is generally more 

weathered than lower horizons (Birkeland, 1974, p. 9) 

and is less subject to the problems of disturbance 

associated with the A horizon.

The A horizon represents the zone of maximum 

leaching (Birkeland, 1974, p. 9), but several factors including its relative thinness, disturbance by 

frost or animals, loss of material by erosion, and accretion of loess, colluvium, or other material make it less 

reliable than the B horizon as a sampling horizon. The 

C horizon is generally less weathered than the B 

horizon (Birkeland, 1974, p. 9), and weathering rinds in 

C horizons are thinner than those in associated B 

horizons.

Weathering-rind thickness appears to progressively 

decrease with depth in the weathering profile, from the 

B horizon downward. In a number of locations, particularly near McCall, Idaho, rind thickness was 

observed to decrease progressively below the standard 

sampling depth. (See, for example, C76-54C versus 

C75-104B, Appendix A.) Porter (1975) has made the 

same observation for rinds in the Yakima Valley. 

Where completely unoxidized parent material was encountered (Cn horizon), virtually no weathering-rind 

development was observed, for example C76-54A (Appendix A).

In contrast to our sampling procedures, some 

workers have used weathering rinds on stones at the 

ground surface (Porter, 1975; Burke, 1979) to determine relative ages. Porter (1975) observed no noticeable difference between surface rinds and shallowsubsurface rinds in the Yakima Valley. Our observations support this conclusion for the Yakima Valley, 

where at least for the younger drifts, the rinds are 

almost as hard as the rock itself. However, a number of 

observations clearly indicate that the rinds on surface 

stones can yield unreliable data for studying weathering with time, especially for older deposits.

First, the hardness of the weathering rinds obviously 

affects their preservation on the surface. The soft, 

mushy rinds produced by advanced weathering are 

almost certain to be eroded from surface stones. The 

rinds on subsurface stones in older deposits in most of 

the sampling areas had to be handled with care in order 

to preserve the full thickness of the weathering rind. In 

the Lassen Peak area, stones which were brought to 

the surface of Tahoe deposits by logging-road construction showed abundant evidence of flaking and 

removal of weathering rinds, even though they had 

been at the surface a few tens of years at most (fig. 4). 

At McCall, Pierce determined that a thin stream of

warm water removed most of the soft rinds on stones 

from older deposits.

Even where the loss of weathering rinds at the surface is not a problem, major differences commonly exist between rinds on surface stones and those on 

shallow subsurface stones. On fine-grained andesitic 

intrusive rocks at the surface of moraines of Pinedale 

age in the West Yellowstone area, weathering rinds 

under lichen-covered surfaces were two or more times 

thicker than those on the undersides of the same 

stones. This difference is consistent with the conclusions of Jackson and Keller (1970), who documented 

greater depths of weathering under lichen-covered surfaces than on lichen-free surfaces on basalt in Hawaii. 

At another Pinedale locality near West Yellowstone, 

rinds were measured on both shallow subsurface and 

surface basalts. The results were 0.44±0.22 (1 standard deviation, n=41) for the subsurface sample, and 

0.67±0.21 (n=25) for the surface sample (collected by 

R. M. Burke, measured by Colman). A probability 

value of less than 0.01 for a Student's t-test provides 

strong evidence against the hypothesis that these two 

samples are from the same population.

Differences in thickness between rinds on surface 

stones and those on shallow subsurface stones may be 

related to differences in duration of exposure to 

weathering. A surface stone begins to weather as soon 

as it is exposed, but weathering of a subsurface stone 

is probably minor until the oxidation front migrates 

downward past the stone. Stones in unoxidized parent 

material have virtually no rinds (C76-54A, for example). An interval of at least several thousand years 

seems to be required before the oxidation zone extends 

to the typical 30-cm sampling depth used in this study.

The formation of rinds on basaltic stones at the surface also may be controlled by different processes than 

those that control the formation of rinds on stones 

within the soil. Rinds on subsurface basaltic stones 

near Wallowa Lake, Ore. (Appendix A), appeared considerably different than rinds on surface basaltic 

stones measured by Burke (1979). The surface rinds 

were thicker on the average, but much more variable; 

many stones have no rinds. The surface rinds were also 

harder and redder than the subsurface ones. One possible explanation for the difference is the effect of 

grass and forest fires on the surface rinds.

Because of the difficulty in controlling the variables 

that affect weathering-rind development on surface 

stones including lichens, fire, rolling by animals, 

uneven wetting, and erosion of weathered materialweathering rinds were sampled from within the 

weathering profile in this study, as described in the
WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

FIGURE 4. Destruction of weathering rinds on stones brought to the surface of Tahoe Till by logging-road construction near Lassen Peak, 

Calif. Outer part of weathering rinds on these two stones of nearly identical lithology is quite soft. Rind on underside of stone on left is 

preserved, whereas rind on exposed upper side of stone on right is flaking off.

preceding section. This procedure minimizes the effect 

of the above variables and helps to isolate time as a 

factor.

In conclusion to this discussion, it should be noted 

that the sampling procedures used in this study are 

most appropriate for deposits in the range of 104 to 105 

yr old. In younger deposits, weathering may not reach 

the depths sampled in this study, and rinds developed 

on surface stones may be more useful for deposits in 

the 103-yr-old range. Deposits older than about 0.5 

m.y. have usually suffered considerable erosion, and 

their surface is probably now below the position of the 

original B horizon. Thus, the weathering of these 

deposits is not strictly comparable to that of younger 

deposits whose surfaces have been minimally lowered. 

Despite this limitation on our methods, rinds on early 

to middle Pleistocene deposits are usually much 

thicker and better developed than those in nearby late 

Pleistocene (about 105-yr-old) deposits, so that rinds 

are still a useful age indicator for the older deposits.

MEASUREMENT PROCEDURES

Rind thickness was measured to the nearest 0.1 mm, 

using a 6-power magnifying comparator containing a 

scale graduated in 0.2 mm increments, on stones that 

were split open and sampled as described in the 

previous section. In most cases, only half or less of the 

perimeter of each stone was appropriate for measuring 

rind thickness. Places not considered suitable for 

measurement include: (1) where the broken face was 

not approximately perpendicular to the outer surface 

of the stone, (2) where part of the rind was crushed or 

flaked in the process of breaking the stone, and (3) 

where the outer surface of the stone was concave outward, allowing soil matrix to cling tightly to the stone.

An important assumption that will be necessary in 

the analysis of the relation between rind thickness and 

time is that the stones on which rinds were measured 

were unweathered when entrained, or were abraded in 

transport, and were therefore deposited with fresh,
FACTORS EFFECTING WEATHERING-RIND THICKNESS

unweathered surfaces. Accordingly, the measured 

weathering rinds developed progressively from the 

time of deposition. Several observations suggest that 

this assumption is valid, and that preexisting rinds on 

stones inherited from bedrock or from older, reworked 

deposits are rare. First, stones sampled from 

unweathered C (Cn) horizons exhibit virtually no rinds 

(C76-54A, for example). Second, stones that show 

evidence of weathering prior to deposition are rare. 

Such stones include those having rinds with asymmetric thicknesses around the stone, which suggests 

partial abrasion of a preexisting rind, and stones 

whose thicknesses are far removed from the distribution of rind thicknesses for the rest of the sample. 

Stones with markedly asymmetric rinds (varying by 

more than a few tenths of a millimeter) were not 

measured. Exceptionally thick rinds were measured 

but were considered outliers to the sample rindthickness distribution; they were not included in the 

calculation of sample means.

On stones that exhibited no visible variation in rind 

thickness, the rind was measured in a single, convenient place. Although formal randomizing procedures 

were not used in the selection of the place where the 

rind was measured, care was taken to avoid obvious 

bias, and the measurements obtained in this manner 

are considered effectively random. In a few cases 

(usually 10 percent or less), rinds exhibited small but 

apparent variation in thickness around the stone. In 

these cases, a place that appeared representative was 

chosen in which to measure the rind. These measurement procedures preclude the use of formal significance levels and precise calculations for statistical 

analysis, but do not invalidate the usefulness of such 

analyses.

In most cases, between 30 and 60 measurements 

were made at each sampling site. With repeated 

measurements of rinds on the same stones, individual 

measurements could usually be reproduced to within 

±0.1 to 0.2 mm, depending primarily on the sharpness 

of the weathering front (the inner boundary of the 

weathering zone). Very thin rinds, in the range of 

0.0-0.1 mm thickness, are at the limit of measurement. 

Such rinds were recorded as 0.1 mm if surface oxidation of the stone obscured the texture of the rock and 

penetrated the stone surface. The rind was recorded as 

0.0 mm thick if the texture of the rock could be seen 

through the slight oxidation of the surface.

ENVIRONMENTAL FACTORS OTHER THAN TIME

Because the main focus of this report is on the relation between weathering rinds and time, we wish to

first evaluate the influence of other environmental factors. Besides the effect of sampling procedures, factors 

that affect chemical weathering features are essentially the same as those that control soil development 

(Jackson and Sherman, 1953, p. 241-248). As discussed previously, these variables are climate, vegetation 

and other organisms, relief (topographic position), 

parent material, and time (Jenny, 1941, p. 15).

As discussed earlier, the variability of rind thickness 

due to sampling techniques essentially has been eliminated by using a standard set of procedures. In addition, the sampling procedures have greatly reduced the 

influence of environmental factors by including only a 

limited range of such factors. Their remaining effect on 

rind thickness is the subject of the following sections. 

The influence of these factors is complex, because the 

factors themselves are interrelated (fig. 5), and their effects are commonly confounded; that is, their effects 

cannot be completely separated.

TOPOGRAPHIC POSITION

Just as erosion and burial affect the development of 

soil profiles, our observations indicate they also affect 

the development of weathering rinds. The effects are 

essentially those described by Jenny (1941) as the 

relief (topography) factor. The effects of erosion and 

burial on weathering-rind development are illustrated 

by the data for sampling sites on till of Hayden Creek 

age near Mount Rainier. The data for these sites (Appendix A) exhibit considerable scatter, which we attribute to the fact that all of the sampling sites except 

two, C76-40 and C78-116, are either being eroded or 

are buried by eolian deposits. The stones at C76-40 

and C78-116, the two undisturbed sites, have much 

thicker rinds than stones at the other sites, even 

though C76-40 and C78-116 are on recessional 

moraines that are at least slightly younger than the 

other moraines sampled.

, Jl lit 1 1 lllf 1

CLIMATE

FIGURE 5

ORGANISMS 

(VEGETATION)

PARENT 

MATERIAL TOPOGRAPHY TIME

1 1 WEATHERING-RIND 

THICKNESS

. Interrelations among factors affecting weathering-rind 

development.
10 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Obviously, where erosion has removed the zone of 

maximum weathering in the upper part of the soil, the 

weathering rinds on remaining stones will be anomalously thin. Sample sites were chosen to avoid actively eroding areas, but especially for relatively old 

till deposits, completely uneroded sites probably do 

not exist. Despite efforts to choose sites with minimal 

erosion, the data suggest that minor differences in 

topography may have an appreciable affect on weathering rinds. For example, three sampling sites were 

located on the crest of the outermost Bull Lake 

moraine near McCall. In order of decreasing average 

rind thickness they are: C75-109 (1.96 mm), just off 

the crest (erosion=deposition?); C76-56 (1.69 mm), on 

a broad, flat part of the crest; and C76-55 (1.44 mm), 

on a relatively sharp part of the crest. Although other 

variables are probably involved, one explanation for 

the differences in rinds among these sites is variation 

in the erosion to which the sites have been subjected.

However, erosion at most sampling sites does not 

seem to have significantly affected rind thicknesses. 

For sites on flat outwash terraces, an assumption of 

negligible erosion can be easily justified. As will be 

discussed in a later section, rind thicknesses from sites 

on outwash terraces were compared with those from 

sites on till of the same age. Rinds sampled from the 

till sites tended to be slightly thicker than those from 

outwash-terrace sites. Although variation in vegetation and soil drainage conditions may affect these rind 

thicknesses, the fact that rinds from the till sites were 

actually thicker than those from the non-eroded 

outwash-terrace sites suggests that erosion of carefully chosen moraine crest sites about 105 yr old or 

younger is relatively minor. Even on older deposits 

where some degree of erosion is unavoidable, carefully 

chosen sites probably yield consistent data with a 

minimum influence of erosion.

Burial of deposits also affects the rate at which 

weathering rinds form in the deposit, principally by 

placing the upper part of the buried deposit below the 

zone of maximum weathering. Many of the study areas 

were locally covered by a mantle of eolian deposits, 

commonly loess. Loess-covered sites were avoided in 

collecting data for the analysis of the relation between 

weathering-rind thickness and time. However, separate comparisons of loess-free sites with sites having 

a variety of loess thicknesses demonstrated that 

relatively thin eolian deposits (less than 50-100 cm) 

did not appreciably slow weathering-rind development 

in the upper part of the buried material. In contrast, 

where eolian deposits are greater than 50-100 cm 

thick, weathering rinds in the underlying deposits are 

commonly quite thin. This was the case with Hayden 

Creek deposits near Mount Rainier, cited earlier; the

Salmon Springs terrace deposits in the Puget Lowland 

are another example. Salmon Springs gravels buried 

beneath thick loess (C76-33, 37A) have rinds only a 

few tenths of a millimeter thick, whereas those beneath 

thin loess (C76-37B) have rinds greater than 1 mm 

thick. Because of these data, only sites with less than 

50-100 cm of loess were used in the analysis of the relation between weathering-rind thickness and time.

PARENT MATERIAL

We deliberately restricted the lithologies on which 

weathering rinds were measured to basalts and andesites. This restricted range of chemical composition, 

mineralogy, and texture automatically reduces variation in weathering-rind thickness. However, basalts 

and andesites still have a range of lithologic variation, 

and the effect of this variation on weathering-rind 

development, along with the effect of the soil matrix, is 

the subject of this section. Many of the comparisons of 

parent material in this section also involve differences 

in climate, so that although the effect of climate will be 

discussed in detail in the next section, climate must 

also be considered in this section.

Apparently, rates of rind development differ for 

basalts and fine-grained andesites of similar textures. 

Although basalts and andesites were seldom found 

together in the principal sampling areas, rind data 

from different areas allow some comparison of rind 

development for the two lithologies. When rind thickness is plotted against time separately for basalts and 

andesites for each of the study areas (see fig. 19), the 

curves plot in order of mean annual precipitation of the 

study areas. However, when basalts and andesites are 

considered together, the relation of the curves to 

precipitation is not clear. This suggests that basalts 

and andesites have different rates of rind development, 

which can obscure the relation between rate of rind 

development and precipitation.

Comparison of rind thicknesses for deposits thought 

to be about the same age in different areas suggests 

that rinds form somewhat faster on basalt than on 

andesite. This observation is consistent with the 

generally accepted conclusion that mafic rocks tend to 

weather more rapidly than felsic rocks (Goldich, 1938; 

Loughnan, 1969, p. 93; Birkeland, 1974, p. 138). Differences in precipitation between areas complicate 

comparisons, but assuming increased moisture favors 

rind development (a point demonstrated in the section 

on climate) the comparisons can still be validly made. 

For example, the basalt-rich Indian John Member of 

the Kittitas Drift in the Yakima Valley and the 

andesite-rich pre-Tahoe till near Lassen Peak are probably about the same age, and have almost identical
FACTORS EFFECTING WEATHERING-RIND THICKNESS 11

rind thicknesses. However, the Lassen Peak area is 

considerably wetter than the Yakima Valley. Had the 

climate of the two areas been similar, the rinds on the 

basalt in the Yakima Valley would have been thicker 

than those on the andesite near Lassen Peak in 

deposits of the same age.

The relative influence of rock type on rind development can be compared to that of other factors, whose 

specific effects are discussed in subsequent sections. 

Between sampling areas, difference in rock type appears to be more important than factors such as 

climate, vegetation, and topography.

Although the influence of climate on the weathering 

of basalts and andesites overrides that of rock type in 

some places in the Western United States (R. W. 

White, oral commun., 1975), in the present study, rock 

type appears to be a greater influence than climate. 

The relative effects of rock type and climate on the 

weathering of basalts and andesites can be assessed by 

comparing: (1) rind thickness for deposits of a single 

age in a single sampling area, and (2) rind thickness for 

deposits thought to be the same age (based on soils, 

morphology, and other relative-age criteria, and on the 

calibrated rind curves developed in this study) in different areas. For the first type of data, rock type is not 

a factor, and climate is the only variable that affects 

rind thickness; for the second type of data, both 

climate and rock type affect rind thickness. Basalts 

and andesites were treated separately, so only the influence of differences among basalts, or among andesites, was considered in the effect of rock type. The two 

types of data are compared in figure 6, where rind 

thickness is plotted against mean annual precipitation.

The first type of data, that affected by climate alone, 

is plotted in figure 6, as well as the second type, that 

affected by climate plus rock type (assuming the correlations are correct). Only one aspect of climate, 

namely precipitation, is considered in figure 6. Other 

climatic parameters, such as temperature, may affect 

the lines in figure 6 significantly, but such effect remains largely unevaluated. The fact that the lines 

representing the influence of precipitation plus rock 

type slope much more steeply than the lines representing the influence of precipitation alone in figure 6 

indicates that precipitation plus rock type has a much 

greater effect on rind thickness than does precipitation 

alone. Therefore, variation in rock type (combined with 

unevaluated variation in climatic factors such as 

temperature) has a greater effect than variation in 

precipitation.

The closeness of fit of points T, U, and V to line 8 in 

figure 6 might be interpreted, by itself, to indicate a 

strong influence of precipitation on rind thickness.

However, other lines representing the influence of 

rock type plus precipitation (for example, line 9) suggest that the fit of points to line 8 is fortuitous; the 

lines representing the influence of precipitation alone

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MEAN ANNUAL PRECIPITATION, IN CENTIMETERS

FIGURE 6. Plot of rind thickness versus mean annual precipitation 

at sample localities in Western United States. Mean annual 

precipitation values are from U.S. Weather Bureau (1959). Points 

A-N are means of individual sites (Appendix A); points O-Z are 

means for all sites for the given age and sampling area. Solid lines 

connect points of the same age, lithology, and sampling area; 

dashed lines connect points of the same general lithology (basalt or 

andesite), of the same inferred age, but from different sampling 

areas; fg, fine-grained andesite; eg, coarse-grained andesite; areas 

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advance.

Point Area

A-F Yakima Valley, Wash.

G-H Truckee, Calif, (fg)

I-J Truckee, Calif, (eg)

K-L Truckee, Calif, (fg)

M-N Truckee, Calif, (eg)

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R Yakima Valley, Wash.

S W. Yellowstone, Mont.

T McCall, Idaho

U Yakima Valley, Wash.

V W. Yellowstone, Mont.

W Mt. Rainier, Wash, (fg)

X Lassen Peak, Calif, (fg)

Y Mt. Rainier, Wash, (fg)

Z Lassen Peak, Calif, (fg)

Age

Bullfrog

Tahoe

Tahoe

Donner Lake

Donner Lake

Pinedale

Domerie

Deckard Flats

(recessional

Pinedale)

Ronald

Pinedale

Bull Lake

Indian John

Bull Lake

Hayden Creek

pre-Tahoe

Hayden Creek

Tahoe

Line

1

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8

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10

10
12 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

in figure 6 indicate a much smaller influence of 

precipitation.

The amount of glass and olivine in the rock is 

another variable that appears to influence the development of weathering rinds. Examination of thin sections of rinds reveals that glass and olivine are particularly unstable in the weathering environment, and 

their alteration is the most important source of oxidation colors in the early stages of rind development. The 

basalts in the deposits in the Puget Lowland illustrate 

this relation. These rocks contain no olivine, and the 

small amount of original glass has devitrified, probably by slight burial metamorphism. Compared to 

basalts that do contain glass and (or) olivine in 

deposits of comparable ages, the basalts in the Puget 

Lowland deposits have anomalously thin weathering 

rinds.

Rock texture is another aspect of parent material 

that can affect the rate of weathering-rind development. A conscious effort was made in sampling to 

minimize variations in texture, but some variation was 

unavoidable. In areas of andesitic rocks, two arbitrarily defined textures were sampled, based on field 

appearance, and were designated fine grained and 

coarse grained (Appendix C). Fine-grained andesites 

contain few or no phenocrysts and usually have a 

dense, aphanitic matrix, whereas in coarse-grained 

andesites, phenocrysts comprise more than one-third 

of the rock volume, and the matrix is somewhat more 

granular. For comparison, average rind thicknesses for 

fine-grained andesites were plotted against those for 

coarse-grained andesites from the same sampling sites 

(fig. 7). On the average, rinds on fine-grained andesites 

are 84 percent as thick as those on coarse-grained 

andesites.

The texture of the soil matrix can also affect the rate 

of weathering-rind development by affecting soil moisture or the rate at which water moves through the soil. 

To evaluate the effect of soil-matrix texture, average 

rind thicknesses for sample sites on outwash were plotted against average rind thicknesses for sites on till, 

for each age of deposit in each sampling area (fig. 8). 

Rinds developed in outwash are, on the average, 89 

percent as thick as those developed in till of the same 

age. The effect of soil-matrix texture is complicated by 

the fact that different soil-matrix textures often support different vegetation communities, and the influences of soil matrix and vegetation on weatheringrind development are difficult to evaluate separately. 

However, the sample data suggest that rinds develop 

slightly faster in till than in outwash. This may be due 

to the finer texture and higher water retention capacity of the till matrix, which allows the soil water more 

time to approach equilibration during weathering reactions. The effect also may be partly the result of the ina. 5

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FIGURE 7. Average weathering-rind thicknesses on stones of finegrained andesite plotted against those of coarse-grained andesite 

from same sampling sites. See text and Appendix C for description 

of rock types. The average ratio of rind thickness on fine-grained 

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RIND THICKNESS IN TILL, IN MILLIMETERS

FIGURE 8. Average weathering-rind thicknesses on stones from outwash plotted against those from till, with age, rock type, and 

sampling area held constant. The average ratio of rind thicknesses 

for sites on outwash to that of sites on till is 0.89.

fluence of different types and amounts of vegetation, 

which is commonly sagebrush or grass on outwash, 

and coniferous forest on till.
FACTORS EFFECTING WEATHERING-RIND THICKNESS 13

VEGETATION

The effect of different types of vegetation on rind 

development is difficult to evaluate because the 

amount and type of vegetation are difficult to measure 

and because amount and kind of vegetation are so 

dependent on climate and parent material. An attempt 

was made to compare rind development at sites bearing forest vegetation with that at sites bearing grass 

and (or) sage vegetation on deposits of the same age. 

However, because most contrasts in vegetation on 

deposits of the same age corresponded with a contrast 

in soil-matrix textures (between till and outwash), only 

five data pairs were obtained for deposits of the same 

age and similar texture, but with different vegetation 

(fig. 9). For these data, rinds developed under grass 

and (or) sage average 87 percent as thick as those 

under forest vegetation. Because of the small number 

of data points, however, the conclusion is tenuous. 

This possibly slower rate of rind formation under grass 

and (or) sage may explain some of the difference between rinds developed in till and in outwash (fig. 8).

Vegetation and soil pH are related, as are pH and the 

degree of weathering (Jenny, 1941, p. 216). Soil matrix 

pH's (1:1, soil:water) were measured for soil samples 

collected at rind sampling horizons in 1975 (Appendix 

B). The variation in pH is small and inconsistent; no 

relation to age or rind development is apparent.

CLIMATE

Climate is a variable that is generally accepted as a 

major influence on weathering processes (Jenny, 1941, 

p. 104; Loughnan, 1969, p. 67; Birkeland, 1974, p. 211). 

Climate includes a large number of interrelated 

variables; however, all of the principal sampling areas 

in this study have similar seasonal distributions of 

temperature and precipitation, so that mean annual 

temperature (MAT) and mean annual precipitation 

(MAP) values are considered reliable variables for purposes of climatic comparisons.

Climatic variables at individual sites may be slightly 

different from those at nearby weather stations due to 

microclimatic, orographic, or altitudinal effects. 

Because most sampling sites were located on flat 

moraine crests or terrace surfaces, climatic differences 

between these sites and nearby weather stations are 

thought to be minimal. No field evidence that would 

suggest major microclimatic effects due to insolation, 

aspect, wind, snow drift, or evapotranspiration was 

observed at any of the sites used in the analysis of the 

relation between rinds and time.

Nevertheless, other data (for sites not used in the 

analysis of the relation between rind thickness and 

time) indicate that climate can change substantially

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FIGURE 9. Average weathering-rind thicknesses on stones from sites 

with grass and (or) sage vegetation plotted against those from sites 

with forest vegetation. Age, type of deposit, and sampling area 

have been held constant. The average ratio between rinds 

developed under grass and (or) sage, and rinds developed under 

forest vegetation is 0.87.

over short distances, and that such changes have an 

important effect on rind thickness. Two sites near 

West Yellowstone, Mont. (C75-102A and 102B, Appendixes A, B), are only about 30 m higher in altitude 

than the weather station at West Yellowstone but are 

in a more favorable topographic position to intercept 

storms. The effect of soil moisture on rind thickness at 

these sites is indicated by snow course data (Fames 

and Shafer, 1975), which suggest that they have 

average snow packs about 1.7 times that at West 

Yellowstone. The average rind thickness at these sites 

is 0.99 mm, compared to 0.78 for sites of the same age 

in a setting closer to that of West Yellowstone. 

Similarly near McCall, Idaho, two sites (C78-124 and 

125) on recessional Pinedale deposits in a side valley 

are located about 400-450 m above McCall. Snow 

course data (Wilson and Carstens, 1975) suggest that 

the snowpack at these sites may be more than 2 times 

that at McCall, although the relationship to moisture 

is complicated by the difference in temperature between the sites and McCall. Rind thickness at these 

sites averages 0.67 mm, compared to 0.25 mm for the 

youngest Pinedale deposits near McCall.

A dramatic example of the effect of precipitation on 

the rate of weathering-rind development is found along 

the Bullfrog terrace (Porter, 1976) in the Yakima 

Valley, Wash. (fig. 10). Weathering rinds were 

measured at six localities along the terrace, over a 

distance of 45 km, in which MAP decreases by a factor 

of about 3, whereas MAT increases by less than 1°C
14 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

(7.9° C at Cle Elum, Wash., 8.3°C at Ellensburg, 

Wash.). Within the area of this climatic gradient, rind 

thickness decreases by a factor of about 2 (fig. 10), 

even though the slight increase in MAT should increase the rates of the chemical reactions that form 

rinds. Thus, the climatic gradient's effect on 

weathering-rind thickness is largely due to moisture 

differences. The influence of moisture differences may 

be partly indirect, through differences in type and 

amount of vegetation, which varies from coniferous 

forest to sparse grass and sage.

Near Truckee, Calif., data from terraces that transect different climatic zones also demonstrate a 

positive correlation between MAP and rind thickness. 

Near Verdi, Nev., MAP is about 50 cm, compared to 

80 cm near Truckee (U.S. Weather Bureau, 1959). Rind 

thicknesses measured in Tahoe and Donner Lake 

deposits near Verdi are generally thinner than those 

for deposits of the same age at Truckee (fig. 6, lines 

2-5). The slope of the rind thickness versus MAP line 

for the Truckee-Verdi area is similar to that for the 

Bullfrog terrace in the Yakima Valley (fig. 6, line 1).

Comparison of rates of weathering-rind development 

between principal sampling areas also illustrates the 

effect of precipitation. Rind thickness versus time 

curves for each area (developed in a later section) 

demonstrates that rates of weathering-rind developFEET 

z 2500 , BULLFROG END MORAINE 

CLE ELUM

I /BULLFROG

METERS 

700

ELLENSBURG"

40 KILOMETERS

FIGURE 10. Elevation, MAP, and weathering-rind measurements 

along the Bullfrog terrace (Porter, 1976), Yakima Valley. The 

precipitation profile is based on records at Ellensburg and Cle 

Elum, Wash., and at several stations upstream from Cle Elum (U.S. 

Weather Bureau, 1959). The rind-thickness values represent the 

mean ±1 standard deviation for the measurements at each site, 

whose location has been projected into the line of profile. Trend line 

of rind thickness against distance down-valley was calculated by 

least-squares regression (r = 0.90). See figure 6, line 1, for plot of 

rind thickness versus MAP.

ment generally increase with increasing MAP. For 

example, basalts in deposits thought to be about 

140,000 yr old at West Yellowstone (50 cm MAP), in 

the Yakima Valley (55 cm MAP), and at McCall (65 cm 

MAP) have weathering rinds averaging 0.78, 1.05, and 

1.57 mm thick, respectively. The West Yellowstone 

deposits have been dated by combined obsidian hydration and K-Ar methods (Pierce and others, 1976), and 

the other deposits are thought to be about the same 

age based on soils, morphology, and stratigraphic relations. These data are plotted in figure 6, line 8; 

however, as noted in the previous section, much of this 

variation in rind thickness is due to differences in rock 

type in addition to differences in climate. The influence 

of precipitation alone is much less than that of climate 

and rock type combined (fig. 6).

The effect of temperature on weathering-rind development remains largely unevaluated because of several problems. First, the range of MAT for the principal study areas is rather small (between 1.7° and 

10.5°C, Appendix B), and the effects of variation in 

MAT are usually masked by the effects of much larger 

variations in MAP, for example, along the Bullfrog terrace in the Yakima Valley, Wash. What variations do 

exist in MAT are usually inversely related to those in 

MAP, and higher temperature and lower precipitation 

(or vice versa) have offsetting effects on rind development. In addition, the effect of temperature on rind 

development is difficult to separate from the effect of 

precipitation; for example, even with MAP held constant, an increase in temperature would result in a 

decrease in soil moisture, thus reducing or perhaps 

even eliminating the effect of the increase in 

temperature. Climatic indices combining precipitation 

and temperature, such as Arkley's (1963) leaching index, have been devised; but in view of the apparent 

dominance of precipitation over temperature as a control on weathering-rind development, the use of such 

an index does not seem warranted.

Observations in a number of secondary sampling 

areas (for example, along the Bighorn River near 

Hardin, Mont: 30 cm MAP, 7.8°C MAT) suggest that 

the development of rinds is inhibited in dry, continental climates, especially where calcium carbonate accumulates within the soil. The presence of carbonate 

implies that relatively little leaching has occurred, 

and carbonate tends to retard the weathering of primary silicates (Grim, 1968, p. 518). The later conclusion was supported by observations in several locations of thicker weathering rinds on the upper, 

carbonate-free sides of stones than on the carbonatecoated undersides.
WEATHERING-RIND DEVELOPMENT AND TIME 15

SUMMARY

Climate, organisms (vegetation), parent material, 

topography, and time the five soil-forming factors 

(Jenny, 1941) are the most important factors affecting weathering processes (Jackson and Sherman, 

1953, p. 241-248), including weathering-rind formation. These factors are also complexly interrelated, 

and most especially climate, organisms, and parent 

material contain subfactors.

The sampling procedures for this study were designed to reduce or isolate the variation in factors 

other than time. Sampling sites were located within a 

relatively narrow range of climate, partly because the 

calcic soils of dry climates are not conducive to 

weathering-rind formation. We restricted variation in 

rock type, the primary parent-material factor in 

weathering-rind formation, by sampling only basaltic 

and andesitic lithologies. Most sampling sites were 

topographically restricted to erosionally stable sites, 

commonly terrace surfaces or flat moraine crests. 

Vegetation at the sampling sites appears to be controlled by climate and soil parent material, which made 

independent evaluation of its direct effect difficult.

We attempted to isolate and evaluate the variation 

in factors affecting weathering-rind development that 

was not eliminated by the sampling procedures. Of the 

factors other than time, variation in the rock type on 

which rinds were measured appears to have the most 

important effect. Variation in climate, especially 

precipitation and possibly also temperature, among 

sampling areas also appears to have a major influence 

on rind thickness. The direct effect of variation in other 

factors, such as vegetation, topography, and soilmatrix texture, seems comparatively minor for our 

sampling sites. Within a sampling area, only data for 

sites with relatively uniform rock type and climate 

were used in the analysis of the relation between 

weathering-rind thickness and time. For these data the 

effect of time is much more important than the effect 

of any of the other factors, and the time factor is the 

subject of the rest of this report.

THE RELATION BETWEEN

WEATHERING-RIND DEVELOPMENT

AND TIME

The ultimate goal of this section is to establish a 

functional relation between weathering-rind thickness 

and time, which can be used as an approximate

numerical-dating method. The analysis begins with 

weathering rinds as a relative-age dating method and 

progresses to a numerical model of weathering-rind 

development with time.

WEATHERING RINDS AS AN INDICATOR 

OF RELATIVE AGE

Several workers have used weathering rinds on 

andesitic and basaltic rocks to discriminate between 

deposits of different ages (Crandell, 1963, 1972; 

Crandell and Miller, 1974; Birkeland, 1964; Kane, 

1975; Porter, 1975, 1976; and Scott, 1977). Following 

the procedure of the latter three workers, the data in 

this study will be presented in terms of means and 

standard deviations. This procedure appears to be the 

most objective and representative way of characterizing rind development for a given sampling site. Other 

measures of rind development, such as maximum 

thickness, are less easy to justify as being representative, even though there appears to be a reasonably 

consistent relation between mean and maximum rind 

thickness (Porter, 1975).

In addition to becoming thicker with time, weathering rinds tend to become softer ("mushier"), with 

increasing stratigraphic age. Although this effect appears to be systematic, we did not develop a quantitative method of measuring this variable.

When the weathering-rind-thickness data are plotted 

according to the stratigraphic ages assigned by 

previous workers (figs. 11, 12; references in fig. 3), the 

data group quite well. This grouping of weatheringrind data by geologic sequence clearly demonstrates 

that weathering rinds are an excellent indicator of 

relative age, and can be used effectively to differentiate deposits of different ages within local sequences. 

The consistency of results for the same age of deposit 

and the consistent differences between different 

deposits, within a sequence, strongly imply that rind 

thickness is controlled by some time function. In addition, the data invite comparisons between areas; for instance, deposits of the last major glacial advance in 

each area all have average weathering-rind thicknesses 

of between 0.1 and 0.3 mm.

Average rind thicknesses for each age of deposit 

within each area (fig. 13; table 1) were calculated by 

averaging the individual measurements for all sites on 

each age of deposit shown in figures 11 and 12. The 

data in figure 13 and table 1 are the primary input for 

the numerical model of weathering-rind development 

with time.
16 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

3.5

3.0

CO

cc

UJ 2.5

2.0

WEST

YELLOWSTONE, 

MONTANA

CO 

CO 

UJ

g

X

IQ

Z

cc

1.5

1.0

0.5-

McCALL, IDAHO

CO <N tYAKIMA

VALLEY,

WASHINGTON

(Porter, 1975)

Carson(1970)

PUGET LOWLAND, 

WASHINGTON

FIGURE 11. Weathering-rind measurements on basalt. Each point and bar represents the mean ±1 standard deviation, respectively, of from 

about 30 to 60 stones measured at one site. Stratigraphic names are those of previous workers (references, fig. 3). See text and Appendix C 

for lithologic descriptions. Areas are arranged east to west. Numbers for McCall area denote sequence of moraines; 1, outermost.

STATISTICAL ANALYSIS

The data presented in the previous section suggest 

that weathering rinds are an effective relative-age 

criterion, and the associated figures provide a qualitative visual comparison of the effectiveness of weathering rinds in separating deposits of different ages. 

The purpose of this section is, first, to quantitatively 

evaluate the conclusion that rind thicknesses can 

separate different ages of deposits, and second, to examine the amounts and sources of variation in the 

weathering-rind thickness data. These goals will help 

define the effectiveness of weathering rinds as a dating 

technique and will suggest the amount of confidence 

that can be placed in the method.

The data analysis1 in this study consists of "exploration" and "approximate confirmation." Tukey (1977,

'The Fisher K-Statistics, Transformation, and Analysis of Variance programs of the U.S. 

Geological Survey "Statpac" (unpub. data, 1979) were used in the analysis.

preface) has described the relative merits of exploration, approximate confirmation, and confirmation 

modes in data analysis. Exact confirmation requires 

specific circumstances and is relatively rigid, whereas 

the flexibility of exploration and approximate confirmation commonly makes them more useful in data 

analysis.

The sampling procedures and data collection for this 

study were designed to explore the amounts and 

sources of variation in rind thickness, as these data 

were largely unknown before the study began. The 

sampling and measurement procedures allow relatively rapid and efficient data collection, permitting 

evaluation of a variety of factors affecting rind 

thickness. However, these procedures are not sufficiently rigorous for precise, formal statistical tests. 

Such confirmatory analysis would require experiments 

in which involved, formal sampling procedures were 

used, and in which some prior knowledge of the 

amounts and sources of variation could be used to
WEATHERING-RIND DEVELOPMENT AND TIME 17

3.5

3.0

CO 

DC 

111

UJ 2.5

2.0

CO 

CO 

HI

TRUCKEE, CALIFORNIA

= 1.5 r^

Q

Z 

DC

1.0

0.5

LASSEN PEAK, CALIFORNIA MOUNT RAINIER, 

WASHINGTON

ttt]

FIGURE 12. Weathering-rind measurements on andesite. Each point and bar represents the mean ±1 standard deviation, respectively, of from 

about 30 to 60 stones measured at one site. Stratigraphic names are those of previous workers (references, fig. 3). Closed circles, fine-grained 

andesite; open circles, coarse-grained andesite. See text and Appendix C for lithologic descriptions. Areas are arranged south to north. Data 

for Logan Hill deposits near Mount Rainier are off the diagram.

design the necessary sampling pattern. In this study, 

lack of prior data on the amounts, nature, and sources 

of variation in rind thickness precluded a confirmatory 

analysis. However, the exploratory analysis accomplished here should allow precise confirmatory 

statistical studies to be designed in the future.

Two aspects of the sampling procedures, in particular, invalidate precise statistical calculations: (1) 

sampling sites were not chosen by formal randomization processes from all possible sites meeting the 

definition of a suitable sampling site, and (2) the selection of the location where the rind was measured on an 

individual stone was not formally random. Although 

we would argue that little or no bias has been introduced by our procedures, they do preclude exact probability calculations for statistical tests. Nevertheless, 

comparisons of the magnitudes of differences and 

amounts of variation are valid, especially because we 

believe that our sampling procedures have introduced 

little bias into the data. This approximateconfirmation procedure permits many useful inferences to be drawn about weathering rinds. The 

following statistical analyses will be interpreted from 

this viewpoint of approximate confirmation.

The definition of weathering rinds and the sampling 

procedures described earlier were conceived partly to 

facilitate the reproducibility of weathering-rind measurements. Reproducibility is an important property of 

any technique of measurement, and in most cases, the 

usefulness of a technique depends on the reproducibility of the measurements. Thus, close replication of 

weathering-rind measurements by different workers is 

critical to the usefulness of rinds as a dating technique.

R. M. Burke assisted us by independently sampling 

and (or) measuring rinds at a number of sites. We also 

compared our measurements in the Yakima Valley 

with those of Porter (1975), who used somewhat different sampling and measuring procedures. In addition, rinds were resampled and measured at a few sites 

at two separate times. The results demonstrate that
18 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES 

TABLE 1. Average weathering-rind thicknesses

[Deposit names are those of previous workers (references, fig. 3); where not specified as terrace or outwash, deposits are till, or till and outwash undifferentiated; in andesite areas, fg, fine 

grained, eg, coarse grained. Thickness entries are the mean ±1 S.D. (standard deviation) of all measurements on a given deposit. In the Yakima Valley, data are from Porter (1975), 

for which standard deviations are apparently for means of site means, and for which the number of sites (-) is not given. Last three entries for Puget Lowland from Carson (1970), in 

which number of sites and number of measurements (-) are not given]

Deposit

Rind thickness 

+1 S.D. 

(mm)

Total 

measurements

No. of 

sites Deposit

Rind thickness 

+1 S.D. 

(mm)

Total No. of 

measure- sites 

ments

West Yellowstone, Mont., basalts Mt. Rainier, Wash., andesites Continued

Deckard Flats

(recessional Pinedale). 0.10+0.07 86 2 

Pinedale terminus 0.40+0.22 80 2 

Bull Lake 0.78+0.19 162 3

McCall, Idaho, basalts

Wingate Hill (fg) -

Wingate Hill (eg) -

Logan Hill (fg) -

Logan Hill (eg) -

3.01+0.69

3.50+0.69

5

£ Q_l_l O Q

8

£ O_l_1 Q Q

80 

39 

56 

15

2

1 

2

1

Puget Lowland, Wash., basalts

Inner Pinedale outwash 

Intermediate Pinedale 

Intermediate Bull Lake 

Average 

Yakima Valley

Thorp 

Mt. Rainier,

Hayden Creek1 (fg) 

0.2540.14 

0.24+0.12 

0.25+0.14

0.31+0.17 

0.38+0.17 

0.35+0.13 

0.35+0.16

0.85+0.24

1.53+0.30 

1.58+0.46

1.71+0.39 

1.61+0.41

, Wash., basalts

0.25+0.04 

0.52+0.06 

0.71+0.12 

1.05+0.17

1.10+0.11 

1.96+0.24

2.78+0.23

Wash., andesites

0.19+0.13 

0.27+0.17 

0.16+0.10 

0.15+0.12

1.37+0.43 

1.95+0.54

164 

39

97 

155 

102

238

74 

181 

99

225 

193 

279 

287

413 

346 

70

94 

28 

80 

123

84 

38

4

1

3 

4 

3

6

2 

4 

3

-

3

1 

4 

4

2

1

High Fraser terrace 

Middle Salmon

Lassen Peak

 LlUgd \Lgf

Tioga (eg) 

r*arj.y i-iugd vigj

"Early Tioga" (eg) 

Tahoe (fg) 

i.dllUc ^cgy

Truckee,

Tioga (fg) 

i-iuga \*~&j

Xdiiwc v *-6 /

Donner Lake (eg) 

Hobart (buried) (fg) 

Hobart (buried) (eg) 

0.23+0.15 

0.21+0.14 

0.71+0.30

0.99+0.36

1.07+0.53 

1.01+0.40

3.3 +2.0

2.6 +2.5 

6 +3

, Calif., andesites

0.17+0.09 

0.16+0.12 

0.33+0.15 

0.36+0.19

0.72+0.23

O oo.n o f.

1.06+0.31 

1.75.+0.63

Calif., andesites

0.16+0.10 

0.18+0.13 

0.21+0.09 

0.22+0.14

0.93+0.24 

0.97+0.23 

0.75+0.22 

1.00+0.30

68 

120 

40

124 

38

78 

156 

150 

192

237 

262 

89 

89

38 

40 

155 

138

106 

103 

31 

39

2 

3

1

2

1

4 

4 

4 

4

6 

6 

3 

3

2 

2 

4 

4

3 

3

1 

1

1 Although several Hayden Creek sites were sampled, the data for only two (C76-40, C78-116) are given, because they 

were the only loess-free, non-eroding sites sampled. Rinds from the other sites were somewhat thinner.

the reproducibility of weathering-rind measurements 

by workers using consistent procedures is quite good

(fig. 14).

Specific topics investigated with statistical procedures include (1) the nature of distributions of sampled 

weathering-rind thicknesses (fig. 15), using moment 

statistics and the x2 distribution, and (2) the importance of the variation in rind thickness with time compared to that with other variables, using analysis of

variance and multiple comparison tests. The detailed 

statistical analyses were performed on the data from 

the McCall and Lassen Peak areas, because of the particularly detailed sampling done in those areas.

NATURE OF THE WEATHERING-RIND MEASUREMENT 

DISTRIBUTIONS

Complete moment statistics were calculated for each 

sampling site; the statistics used were Fisher K-statis-
WEATHERING-RIND DEVELOPMENT AND TIME 19

BASALT ANDESITE

3.5

3.0

2.5

2.0

1.5

1.0

0.5

n

0 

L

«

_

UJ

O

55

as*c

L.

0

> 

>

3J

i

>

CO 2

1 3

- 1 1

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J

-

 £

Ta

_LL 

TJ

a '

o

CD O

t

McCALL

CD

CO

TJ

CD

CO

=

m

i

2 £

CL D.- 

r * ^ CD

[

£"3 

(<D

,

9

1

YAKIMA

(Porter, 1975)

CO

i

^ h A

1 '

CD

CO

TJ

*

JC. Q)

r * oE

CD (jj

=5 5

.£ CO lit CO

32 1

0 I

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c.

CD

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5

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LOWLAND

CD

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CB

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o>

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®

« OT i

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eo ^5 

co CO

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CO

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^

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CO 1 CO Jit

s *

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9

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3)

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j,

CD 

CD

O

TJ

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CD

TJ

CD

5

JL. 

CD 

CD

O

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CD

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TRUCKEE

T

1

'i

5 i

CO "

_l »

,_ (

3

I

5

i

CD O 

C O

c X 

O

1

<

CD 

O

g s, "g

i- 1

iHt

(i

LASSEN

CD

O

JZ

CO hCD

CL

CD 

O

£ 

CO

"c"

c. n

0

ii

>, <

LLJ

CO

O)

O

i'

i

RAINIER

o

.c

CO

1

CD ' CD

O

c

CD

TJ

CO

X

i

il"

X

c

CO

O) 

o

^X

<1s

o>

c

^

^>

CD

CD 

6

CO

c

CO

111 II

CO 

CC

UJ

%

UJ

Q

Z 

CC

FIGURE 13. Average weathering-rind thicknesses for the sequence of tills and terraces recognized in each of the principal sampling areas. 

Each point and bar represents the mean ± 1 standard deviation, respectively, of all rind measurements for each age of deposit in each 

sampling area. Stratigraphic names are those of previous workers (references, fig. 3). In areas of andesitic rocks, closed circles, finegrained andesite; open circles, coarse-grained andesite. See text and Appendix C for lithologic descriptions. Areas arranged as in figures 

11 and 12. Arrows indicate data off the diagram.

tics, including g^ (skewness) and g2 (kurtosis) (Fisher, 

1954). The gl and g2 statistics, which have expected 

values of zero for normal distributions, were used to 

examine the types of distributions represented by 

weathering-rind measurements. The results (table 2) 

indicate that the distributions of weathering-rind 

measurements have a slight tendency to be skewed to 

the left (gl positive); measurement distributions of 

basalt at McCall and of fine-grained andesite at Lassen 

Peak tend to be platykurtic (flat, g2 negative), whereas 

measurement distributions of the coarse-grained andesite at Lassen Peak tend to be leptokurtic (peaked, gz 

positive).

Confidence limits for gl and g2 values calculated for 

rind-measurement distributions can only be estimated, 

because of the lack of rigor in the measurement

methods (p. 17), and because the variances of gl and g2 

are precise only for sample sizes greater than about 

100 (Griffiths, 1967, p. 262). However, these confidence levels are useful for comparison. Ten of the 85 

calculated gl values for the McCall and Lassen Peak 

areas exceed the confidence limits (Griffiths, 1962, 

a= 0.05) for the expected value of zero for normal 

distributions. Chi-square statistics were also 

calculated for the 10 distributions with high gl absolute values. Only four of the x2 values exceeded the 

confidence limits (a= 0.05) for normal distributions. 

These comparisons, while not rigorously precise, suggest that weathering-rind distributions can reasonably 

be considered normal distributions.

The skewness (positive) of the distribution is 

especially apparent for sampling sites with very thin
20 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

o.u

COtr

P 2.5

HI

5

_l

S 2.0

Z

CO"

CO

LU 1.5

O

I h- 

_ 1.0

Q

Z

tr

z

a ° s

^

0

I I I I I '

_ x /

0 X

AjX^

.'

- oX -

/

y EXPLANATION

rrdT *

2^ + + ° B

/NlY ° °

~ .'X A D ~

-H- + E

/*" I I I II

0.5 1.0 1.5 2.0 2.5

MEAN RIND THICKNESS, IN MILLIMETERS

3.0

FIGURE 14. Reproducibility of weathering-rind measurements. Data 

collected by S. M. Colman are plotted on the abscissa. In A, 1975 

measurements are plotted on the abscissa A, samples taken and 

measured by S. M. Colman in 1976 versus samples taken and 

measured by S. M. Colman in 1975 at the same site; B, 

measurements by K. L. Pierce versus those of S. M. Colman; C, 

measurements by R. M. Burke (written commun., 1976) versus 

those of S. M. Colman; D, measurements by Porter (1975) versus 

those of S. M. Colman; E, samples collected by K. L. Pierce versus 

those collected by S. M. Colman at adjacent sites; all 

measurements by Colman.

TABLE 2. Skewness (gj and kurtosis (gj for weathering-rind-thickness distributions

Statistic Number Number 

Data set positive negative

McCall, Idaho 0

Lassen Peak, Calif. ^

(fine-grained) .

Lassen Peak, Calif., g

(coarse-grained).

1 26ot

1 x

1 15

7

1

2

McCall, Idaho g 2 9 24 

Lassen Peak, Calif. g 2 6 11

(fine-grained). 

Lassen Peak, Calif. g 2 I 3 4

(coarse-grained).

weathering rinds (fig. 15). In an attempt to reduce the 

skewness in the distributions, the data were subjected 

to a log transformation and the moment statistics were 

recalculated. Compared to the untransformed data, the 

positive and negative values of gl and g2 are more 

evenly distributed for the log transformation data, and 

tend to have lower absolute values.

Thus, based on gl and g2 statistics and on the x2 

distribution, both the linear and log data fit the normal 

distribution model quite closely. Analysis of variance, 

discussed in the next section, was calculated for both 

the linear and log data; the conclusions that can be 

drawn from the analysis of the two sets of data are 

identical. However, the fact that the data are slightly

20

O

HI

Z> 10 

O

HI tr

C75-84 C75-06 C76-24 C76-66 C76-45

15

O

o

HI tr

0.5 1.0

C75-85 C75-79 C75-100 C76-56

m i \m i

m m

0.5 1.0 0 0.5 1.0 0 0.5 1.0

RIND THICKNESS, IN MILLIMETERS

C76-02

0.5 1.0 1.5

C75-126

LiL

0.5 1.0 1.5 0.5 1.0 1.5 2.0 0.5 1.0 1.5 0.8 1.6 2.4 3.2 0.4 1.2 2.0 2.8 1.5 2.4 3.3 4.2

RIND THICKNESS, IN MILLIMETERS

FIGURE 15. Selected histograms of weathering-rind measurements. Sampling site number is given above each histogram; mean and standard 

deviation for each site are given in Appendix A, and site locations are given in Appendix B. Note different rind-thickness scales.
WEATHERING-RIND DEVELOPMENT AND TIME 21

closer to a log-normal distribution than to a linearnormal distribution is significant and will be a useful 

piece of evidence in the construction of rind thickness 

versus time curves.

ANALYSIS OF VARIANCE

The nested sampling design for the McCall (fig. 16) and 

Lassen Peak areas was chosen so that variation in rind 

thickness from several sources could be compared 

using analysis of variance. The McCall sampling design has four nested subdivisions: (1) ages, (2) moraines 

within each age, (3) sites within each moraine, and (4) 

measurements within each site; the Lassen Peak 

sampling design has three subdivisions: (1) ages, (2) 

sites within each age, and (3) measurements within 

each site. The importance of variance contributed from 

each of these levels can be evaluated by analysis of 

variance procedures. The calculations (table 3) were 

made using the general methods of Anderson and Bancroft (1952) and Snedecor (1956) on the linear data.

The general model used in the analysis of variance is 

a nested oneway model in which any individual 

measurement X(i, j, k,...r) has the value X(i, j, k,...r) 

= M + A(i) + B(i, j) + CO, j, k) +...+EO, 7, k,...r) where 

M is the grand mean;

A, B, C,...E are random and normally distributed with 

zero means and variances V(A), V(B), V(Q,...V(E); 

i, j, k,...r are the nested levels in the subdivision. 

Each F-ratio test in the analysis tests the null 

hypothesis: "These subsamples are random samples 

from the same normal population."

The nested levels in the sampling design isolate 

sources of variation and allow them to be compared. 

Measurement errors are confined to the measurement 

level, whereas local differences in rock type, climate, 

and vegetation are contained in the site and moraine 

levels. Differences in age, of course, are contained in 

the age level.

For the McCall data, the variation in rind thickness 

among ages is very large (F=182) compared to that 

among moraines, and the variation among sites is 

large (F=15) compared to that within a site (among

gUJ 1570 

1530 

1510-

LJJ 

UJ

INNER 

PINEDALE

OUTER 

PINEDALE INTERMEDIATE BULL LAKE AGES

nn umnnn n m

0)

cc

UJ

O

I

Q

Z 

CC

I

MEASUREMENTS

4 KILOMETERS

FIGURE 16. Diagrammatic sketch of the nested sampling design for the deposits near McCall, Idaho. Sampling was based on mapping by 

Schmidt and Mackin (1970). Short line pattern, till; stipple, outwash. Measurements are summarized as the mean ±1 standard deviation 

rather than the branches for the 30-60 measurements at each sampling site. Kilometer scale is approximate.
22 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

TABLE 3. Analysis of variance, McCall and Lassen Peak data

Analysis of variance Components of variance Test of hypothesis

Sum of Degrees of Mean Unit Variance 

Source squares freedom square Level size component Percent F-Ratio Estimated p 1

McCall (basalt)

fUUVLJ.^ CL^^-O

Among morainesAraong sites 

Within sites 

Total 

Among sites 

Within sites 

Total 

Among ages 

Among sites 

Within sites 

314.040 

4.025 

21.132 

81.633

420.830

44.323 

6.462 

24.778

75.563

167.360 

22.686 

60.396

2 

5 

18 

958

983

3 

13 

493

509

3 

13

574

104.680 

.575

1.057 

.072

Lassen Peak

14.774 

.497 

.050

Lassen Peak

55.788 

1.745 

.105

1 

2

3

4

3 

8 

26 

984

(fine-grained

1 

2 

3

4 

17 

510

(coarse-grained

1 

2 

3

4 

17 

591

0.36185 

.00513 

.02646 

.07192

0.46024

andesite)

0.11971 

.01494 

.05026

0.18491

andesite)

0.37108 

.04968 

.10522

78.62 

.00 

5.75 

15.63

100.00

64.74 

8.08 

27.18

100.00

70.55 

9.45 

20.00

182.060 0.00018 

.544 .378 

14.690 1.8xlO~ 18

29.719 2.1xlO~6 

9.891 3.2x10-12

31.969 7.3xlO~7 

16.585 1.3x10-16

Total- 250.452 590 0.52598 100.00

, probability that the null hypothesis is true

measurements). However, the variation among 

moraines is small (F=0.5) compared to that among 

sites. For both the Lassen Peak fine- and coarsegrained data, the variation among ages is large (F=30 

and 32) compared to that between sites, and the variation among sites is large (F=10 and 17) compared to 

that within a site (among measurements). All comparisons, except that between moraines and sites at 

McCall, allow for only a slight possibility that the null 

hypothesis is true.

The most important conclusion from the analysis of 

variance is that, within a given study area, the variation in rind thickness between different ages of 

deposits is more important than all other sources of 

variation, including variation due to differences in rock 

type, climate, and vegetation. The components-ofvariance analyses in table 3 suggest that differences in 

age contribute about 65-80 percent of the total rindthickness variance. Another important conclusion is 

that, at McCall at least, any differences in rind 

thickness between moraines of one stratigraphic unit 

are not important compared to other sources of variation in rind thickness.

MULTIPLE COMPARISONS

The analysis of variance indicates that important 

differences in average rind thickness exist among sites 

and among ages of deposits, but it does not indicate 

which differences are important. Multiple comparison tests allow direct comparisons of differences in 

rind thickness and determine which differences are 

important.

The method used in this study is that of Scheffe 

(1959). The derived statistic for comparison is

D= (k-l)

where

Ds is the significant, or critical, difference for the

comparison; 

S2 is the mean square residual (error mean square

in the analysis of variance); 

Ct is the coefficient of comparison of sample

mean t;
WEATHERING-RIND DEVELOPMENT AND TIME 23

Nt is the number of observations in sample t\

k is the number of samples in the class being examined;

F is the F-ratio for the given probability and 

degrees of freedom;

N0 is the total number of observations in the class 

being examined; and

a is the probability level.

For comparison of two means, the statistic reduces to

The multiple comparison tests (table 4) prove the importance of age (time) in weathering-rind development. 

All differences in mean rind thickness between 

stratigraphic ages of deposits exceed the critical differences (Ds) calculated for a probability of 0.05 by 

Scheffe's method. Differences in mean rind thickness 

between closest pairs of ages exceed Ds by factors 

ranging from 1.4 to 13.3. Clearly, weathering-rind 

thickness effectively discriminates between different 

ages of deposits.

For moraines within one age of deposit, the conclusions are the opposite of those for ages. None of the differences in mean rind thickness between moraines of 

one stratigraphic age at McCall (the only area where 

moraines were tested) exceed Ds, except for one case. 

This indicates that at McCall, moraines of each 

stratigraphic unit are all similar in age. The exception 

is the outermost Bull Lake moraine, which has a mean 

rind thickness that exceeds Ds in comparisons with the 

other two Bull Lake moraines by factors of 2.0 and 3.4. 

Because this moraine cannot be distinguished from the 

other two by any method other than weathering rinds, 

it remains grouped with the other two Bull Lake 

moraines as a map unit.

For sites within one stratigraphic age of deposit, 

comparisons of mean rind thicknesses yield mixed 

results (table 4). Generally, for relatively young 

deposits, the differences between sites of one age do 

not exceed Ds, suggesting that the samples come from 

a single age population. In contrast, differences in 

mean rind thickness for sites of the same stratigraphic 

age within older deposits exceed Ds in some cases. 

However, the majority of comparisons do not exceed 

Ds, and those that do commonly contradict the 

stratigraphic sequence of moraines within the deposit. 

In some cases, sites on different moraines have differences in rind thickness that do not exceed Ds, 

whereas the differences that exceed Ds are commonly 

for sites on the same moraine. Therefore, the different 

populations suggested by the differences in rind

thickness that exceed Ds are probably not produced by 

differences in age but by local differences in other factors such as climate, rock type, or surface stability.

SUMMARY OF STATISTICAL ANALYSIS

Statistical analysis demonstrates that weathering 

rinds are an excellent quantitative indicator of age. 

The rind measurements can be closely reproduced, and 

they tend to be nearly normally distributed, with a 

tendency for positive skewness. Analysis of variance 

indicates that, within a sampling area, the age of the 

deposit sampled is the most important source of variation in rind thickness. Multiple comparison tests 

demonstrate that, within a sampling area, (1) all differences in mean rind thickness between different 

stratigraphic ages of deposits are important, (2) differences in mean rind thickness between different 

moraines of the same stratigraphic age are generally

TABLE 4. Summary of results of Scheffe's multiple comparison 

test (u=0.05)

Comparison group

Number Number not 

exceeding exceeding

Comparisons between sites

McCall inner Pinedale 0 10

McCall outer Pinedale 0 45

McCall intermediate 6 15

McCall Bull Lake 17 19

Lassen (fg) Tioga 0 6

Lassen (fg) early Tioga- 2 4

Lassen (fg) Tahoe 3 12

Lassen (fg) pre-Tahoe 2 1

Lassen (eg) Tioga 0 6

Lassen (eg) early Tioga- 0 6

Lassen (eg) Tahoe 1 14

Lassen (eg) pre-Tahoe 2 1

Comparisons between moraines

McCall inner Pinedale 0 3

McCall outer Pinedale 0 3

McCall intermediate 0 1

McCall Bull Lake 2 1

Comparisons between ages

McCall 6 0

Lassen (fg) 6 0

Lassen (eg) 6 0

L fg, fine grained; eg, coarse grained.
24 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

negligible, and (3) differences in mean rind thickness 

between sites of the same stratigraphic age may be important, but the differences are largely due to factors 

other than age.

NUMERICAL MODELS OF WEATHERING-RIND 

DEVELOPMENT WITH TIME

The extraction of numerical-age information from 

weathering-rind measurements can be done in two 

ways: (1) rind-thickness ratios, and (2) rate curves. 

Although the ratio of the rind thicknesses for two 

deposits does not provide numerical ages for the 

deposits, such ratios can provide very useful information on the magnitude of the age difference between 

the deposits. In addition, if the numerical age of one 

deposit is known, rind-thickness ratios provide limits 

to the possible ages of other deposits in the same area. 

Rate curves have the major advantage of allowing 

numerical ages to be calculated directly from the data, 

but the rate curves need to be defined and calibrated. 

Because of the paucity of independent age determinations, definition of rate curves based on several 

deposits within a sequence requires major assumptions whose validity cannot at present be proven. In 

the following sections, we will first examine rindthickness ratios as a means of estimating minimum 

and maximum probable age differences between 

deposits, and then we will attempt to develop rate 

curves using dated sequences from West Yellowstone 

and elsewhere.

RIND-THICKNESS RATIOS

The ratio of rind thicknesses from two deposits in 

the same sequence provides a simple index to their age 

relations. We can estimate with considerable confidence the minimum and maximum age ratios indicated by these rind ratios. Therefore, from the rindratio data for two deposits, we can infer either limits 

on their age ratio, or, if one age is known or assumed, 

we can infer the minimum and maximum value for the 

other age.

Within a given local sequence of deposits, the factors 

of climate, vegetation, topography, and parent 

material at the sampling sites were generally held 

nearly constant; time is the only remaining major 

variable affecting rind thickness. However, because 

Quaternary climate has fluctuated, the rate of 

weathering-rind development may also have changed, 

especially between glacial and interglacial times. 

Therefore, deposits of different ages have been subjected to different climatic histories and may have 

weathered under different average climates. With our

present information, we are not able to calculate this 

effect. However, the decrease in the rate of rind formation due to colder temperatures during glacial times 

would tend to be compensated for by an increase in 

rate due to a probable concomitant increase in soil 

moisture. Assuming that the total effect of climatic 

change on the rate of rind development is minor, and 

for present purposes can be neglected, we now attempt 

to bracket the maximum and minimum age relations 

indicated by the rind ratios.

Three basic types of functions can be postulated for 

the relationship between rind thickness and time:

1. linear: d = kt or t = kd

2. logarithmic1 : d - k log t or t = k(lO)d

3. power function: d = ktlln or t =

where d = rind thickness, t = time, n is an unspecified 

exponent, and k is a rate factor due to variables other 

than time. In each case, calculation of rind thickness 

ratios (djd2) eliminates k by division and leaves the age 

ratios (tjt2) as a function of rind thicknesses only:

4. linear: djdz = tjt2

5. logarithmic: djd2 = log tflog tz

6. power function: djdz = (tilt2)lln

Rind thickness ratios for deposits sampled in this 

study (table 5) can therefore be used to estimate age 

ratios within each sampling area, where the value of 

the rate factor k is approximately constant.

In the past, the rate of change of features due to 

weathering has been assumed by some workers (for example, Birkeland, 1973) to be constant, especially in 

the absence of independent age estimates; but many 

workers now believe that the rate of change of most 

weathering features decreases with time (Cernohouz 

and Sole, 1966; Oilier, 1969, p. 252; Carrara and Andrews, 1975; Birkeland, 1974, p. 176; Winkler, 1975, 

p. 151; Pierce and others, 1976; Porter, 1976). A constant rate corresponds to a linear function (eq. 1), 

whereas a decreasing rate can be represented by either 

a logarithmic curve (eq. 2), or a power function curve 

(eq. 3( with n >1. The rate of change of some weathering 

features may decrease to values approaching zero, in 

which case a steady state is reached.

In table 5, the rind-thickness ratios are presented in 

two forms: (1) the simple rind-thickness ratio, which is 

appropriate for estimating the age ratio if rind thickness is a linear function of age, and (2) the rind ratio 

squared, which is appropriate for estimating the age 

ratio if rind-thickness is a power function (re =2) of age.

'Use of the base 10 is convenient but arbitrary; the natural base (e) or other bases would 

be equally valid for the general case.
WEATHERING-RIND DEVELOPMENT AND TIME 25

TABLE 5. Rind-thickness ratios

Rind ratio Rind ratio suared

Deposits (minimum age (maxlmum(?) age 

ratio) ratio)

West Yellowstone (Deckard Flats/Plnedale/Bull Lake)

* Deckard Flats-Pinedale terminus 

* Deckard Flats-Bull Lake 

Plnedale terminus-Bull Lake 

4.0 

7.8 

2.0

16 

61 

3.8

Me Call (Plnedale/Intermedlate/Bull Lake)

* Inner Plnedale-lntermedlate Plnedale 

* Intermediate Plnedale-outer Plnedale 

Plnedale average-Intermediate 

Plnedale average-Bull Lake average 

Intermediate-Bull Lake average 

Inner Bull Lake-outer Bull Lake 

1.2 

1.3 

3.0

5.0 

1.7 

1.1

1.5 

1.6 

8.8

25 

2.9 

1.3

Yaklma Valley (Domerle/Ronald/Bullfrog/Indlan 

John/Swauk Pralrle/Thorp/pre-Thorp(?))

Bul 1 f r og-Ind lan John 

Indian John-Swauk Prairie 1 

Mount Rainier (Evans Creek/Hayden

* Evans Creek-Hayden Creek 

* Evans Creek-Wlngate Hill 

Hayden Creek-Wlngate Hill 

Wlngate Hlll-Logan Hill 

2.1 

2.8 

1.4 

1.5

1.1 

1.8 

1.4

Creek/Wlngate

9.1 

19 

2.1 

1.9

4.3 

8.1 

1.9 

2.2

1.2 

3.2 

2.0

Hlll/Logan Hill)

82 

354 

4.3 

3.6

Puget Lowland (Vashon-Low Fraser terrace/ 

High Fraser terrace/Salmon Springs)

* Low Fraser terrace-Vashon 1.1

* Low Fraser terrace-High

Fraser terrace 3.4

* Vashon-Salmon Springs 4.4 

High Fraser terrace-Salmon Springs 1.4

1.2

11

19

2.0

Lassen Peak (Tloga/"Early Tloga"/Tahoe/pre-Tahoe)

* Tloga-pre-Tahoe 

"Early Tloga"-Tahoe 

"Early Tloga"-pre-Tahoe 

1.9

4.2

6.2

2.2

3.2

0 Q

1 R

39

4.8

10

Truckee (Tloga/Tahoe/Donner Lake)

Tloga-Tahoe 1.3

Tloga-Donner Lake 5.8

Tahoe-Donner Lake 4.4

1.7

34

20

^Swauk Prairie deposits may have anomalously thin rinds due to 

thick loeas cover.

Because the rate of rind formation almost certainly 

decreases with time, as is argued in the next section, 

the simple rind-thickness ratio (thicker rind to thinner 

rind) is a minimum estimate of the age ratio. The exponent of n=2 is appropriate for simple diffusion reactions, such as obsidian hydration (Friedman and 

Smith, 1960). Rinds appear to form by a combination 

of oxidation, hydrolysis, and solution processes (Colman, 1977), for which an exponent of two is probably a 

maximum; thus the rind ratio squared is probably near

the upper limit of the age ratio. Therefore, table 5 provides the probable upper and lower limits of the age 

ratios of the listed deposits.

As an example of the utility of table 5, Pinedale and 

Bull Lake terminal moraines near West Yellowstone 

have rind thicknesses of 0.40 and 0.78 mm respectively, for a ratio of about 2, and a ratio squared of 

about 4. Their ages, independently determined by 

Pierce and others (1976), are about 35,000 and 140,000 

yr, respectively, for an age ratio of 4.0. Thus table 5 

can be used to place limits on the age difference between the West Yellowstone Pinedale and Bull Lake 

deposits independently of other age estimates. Our 

best estimate for rind thickness versus time functions, 

derived in the next section, almost invariably produces 

age ratios between the limits of the rind ratio and the 

rind ratio squared proposed in table 5.

The rind ratio approach to extracting numerical age 

information from rind data is presented before we give 

our preferred rate-curve model. The assumptions used 

in estimating the maximum and minimum age ratios 

are few, and, we think, readily justified. Thus, the age 

constraints provided by rind ratios are relatively 

definitive data. Age inferences or correlations incompatible with the constraints provided by the rind ratios 

are therefore open to serious question.

TIME-STRATIGRAPHIC NOMENCLATURE

Because of lack of agreement in the usage of time terminology for the Quaternary, we will define the time 

terms that will be used in the following sections on 

numerical ages and correlations. Our primary reference 

is the marine oxygen-isotope record (Emiliani, 1955, 

1966; Broeker and van Donk, 1970; Emiliani and 

Shackleton, 1974; Shackleton, 1977a), which has been 

shown to be dominantly a record of worldwide ice 

volume (Shackleton and Opdyke, 1973). Figure 20 

(p. 32) shows four such oxygen-isotope records plotted 

on a common time scale. We consider the last interglaciation to be equivalent to all or part of isotope 

stage 5, the period independently dated as between 

about 75,000 and 125,000 yr ago. The Toba Tuff in 

North Sumatra has been dated by K-Ar as 75,000 yr 

old, and occurs in deep-sea cores at the stage 4-5 

boundary (Ninkovich and others, 1978); oxygenisotope values for stage 5e and for the corals at the 

high sea stand in Barbados (dated by U-series methods 

as 125,000 yr old) demonstrate their equivalence 

(Shackleton, 1977b).

The isotopic record demonstrates that there were 

fluctuations in ice volume during^stage 5, and some 

workers have argued that only the earliest part, stage
26 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

5e, represents the last interglaciation, and that stages 

5b and (or) 5d represent early phases of the last glaciation, especially at high latitudes (see references in 

Suggate, 1974). For temperate latitudes, such as the 

locations of the sampling areas in this study, we provisionally accept the arguments of Suggate (1974) that 

the last major interglacial-to-glacial transition occurred at the boundary between stages 5 and 4, about 

75,000 yr ago. This agrees with the estimates of 

Willman and Frey (1970) and Dreimanis and Karrow 

(1972) for the beginning of the Wisconsin Glaciation. 

The temperate-latitude Wisconsin thus encompasses 

isotope stages 2-4. In our usage, early Wisconsin 

refers to glacial culmination(s) within stage 4, about 

60,000 to 70,000 yr ago, and late Wisconsin refers to 

glacial culmination(s) within stage 2, about 12,000 to 

22,000 yr ago. Our mid-Wisconsin glacial advances occurred during the middle part of stage 3, between 

about 30,000 and 50,000 yr ago, and would be approximately correlative with the late Altonian advance in 

the mid-continent, which culminated about 32,000 yr 

ago (Willman and Frey, 1970; Dreimanis and Karrow, 

1972).

Most oxygen-isotope records indicate that ice 

volume during stage 6 (about 130,000-150,000 yr ago) 

was at least as great as that during any time since. We 

consider glacial deposits correlating with stage 6 to be 

latest pre-Wisconsin, sometimes called the penultimate glaciation.

RiTE CURVES FOR WEATHERING-RIND THICKNESS

The paucity of independent numerical ages for 

Quaternary deposits in the Western United States presents a major obstacle to determining the exact relation between rind thickness and time. The only glacial 

sequence examined in this study for which there are 

numerical ages older than the last major advance is 

that at West Yellowstone. This sequence has been 

dated by Pierce and others (1976) using combined 

obsidian-hydration and K-Ar dating.

A curve for the development of weathering rinds 

with time has been constructed for basalts in Bohemia 

by Cernohouz and Sole (1966), using seven ages ranging from 600 yr to about 2,000,000 yr. They do not 

state the basis for the ages, so it is difficult to evaluate 

their data; but their curve fits their data points extremely well (fig. 17). This rate curve is of the form

d=A log(l+Bt)

where d=rind thickness, t=time, and A and B are 

constants.

2.4

22

s» 2 -°

|£ 18 

Sfc 1 - 6 

gi 1 ' 4

Q 5 1.0

|zo.e

0.6 

0.4 

0.2

I I p I ' I ' 1 1 I '

"BOHEMIA (CERNOHOUZ + SOLC, 1966) 

d = 4.64 LOG (1-f 0.01 t)

WEST YELLOWSTONE 

d = LOG (0.73+ 0.038 t)

0 20 40 60 60 100 120 140 160 180 200 220

TIME (103 YEARS B. P.)

FIGURE 17. Weathering-rind thickness versus time curves ^for 

Bohemia and West Yellowstone. The Bohemia curve is from Cernohouz and Sole (1966), and is based on the four points shown in addition to three points with ages greater than 220,000 yr. The West 

Yellowstone curve is based on the logarithmic form of the Bohemia 

curve, on obsidian-hydration ages (Pierce and others, 1976), and on 

rind-thickness data from this study. The difference between the 

two curves results from differences in rock type, climate, and other 

factors between^ the two areas. Error bars on data points are from 

Cernohouz and Sole (1966) for Bohemia; for West Yellowstone, time 

error bars are from Pierce and others (1976) and rind-thickness error bars are ±1 standard deviation (this study, table 1).

The West Yellowstone data (fig. 17) demonstrate 

that rind thickness is not a linear function of time; the 

rate of rind formation clearly decreases with time. We 

attempted to fit (by inspection) various types of power 

function and logarithmic curves to the data, and of 

these curves, a logarithmic curve of the same form as 

the curve for Bohemia (Cernohouz and Sole, 1966) appeared to fit the data best.

A date of about 35,000 yr was used for the Pinedale 

deposits at West Yellowstone, rather than about 

30,000 yr as calculated by Pierce and others (1976) 

using a maximum temperature correction. The rind 

thickness for the terminal Pinedale deposits is 

somewhat higher than would be expected for a logarithmic curve through the data for the other West 

Yellowstone deposits. This may be due to the fact that, 

unlike Deckard Flats (recessional Pinedale) and Bull 

Lake deposits, which are basalt rich, the terminal 

Pinedale deposits consist of scattered basalt clasts in a 

rhyolite-rich deposit. The rhyolitic material appears to 

alter very slowly, and the weathering in these deposits 

seems to be concentrated in the scattered basaltic 

clasts, which may thus exhibit slightly thicker than expected rinds.

Unlike the Bohemia curve, which intercepts the 

origin, the West Yellowstone curve has been constructed with the zero rind-thickness intercept at 7,000 

yr (fig. 17). The curve with this intercept is meant to 

approximate a curve with two segments; that is, one
WEATHERING-RIND DEVELOPMENT AND TIME 27

whose rate begins slowly but which eventually attains 

a logarithmic form (fig. 18). Three arguments suggest 

that a curve similar to curve C in figure 18 is appropriate. First, some time is necessary for weathering 

processes, especially oxidation, to reach the depths 

sampled in this study. Second, because weathering 

rinds are initially a surface phenomenon, it is 

reasonable to expect that much of the early surface 

weathering will take place on grains in the soil matrix, 

which have a much greater surface area than the larger 

clasts. Third, the fact that most of the late glacial 

deposits, on the order of 12,000-15,000 yr old, have 

very thin weathering rinds (for example, 0.1 mm for 

Deckard Flats (recessional Pinedale) deposits near 

West Yellowstone) suggests that the early stages of 

rind formation are very slow at the depths sampled. 

The figure of 7,000 yr for the intercept may not be 

precisely applicable to all sampling areas because of 

differences in climate and soil parent material, but in 

many cases variations due to these factors tend to offset each other. Also, the ages estimated from the rind 

curves for deposits older than the last major glacial advance change only slightly if the intercept value is 

changed. Therefore, 7,000 yr was used as the intercept 

for all the rate curves; inaccuracies in age estimates 

due to the intercept value are small compared with 

other uncertainties in the rate curves.

Birkeland (1974, p. 176) presented several inflected 

curves similar to curve B (fig. 18) as models for 

weathering and soil development processes. Winkler 

(1975, p. 148-151) reviewed several weathering studies 

and concluded that weathering rates may initially increase exponentially, and probably eventually decrease 

exponentially. The fact that the distributions of 

weathering-rind measurements tend to be log normal 

supports the logarithmic form of the rate curve.

Because climate affects rind development, fluctuations in climate in the past have had an effect on the 

rate of rind formation. Because data for evaluating 

this effect are not available, the rate curves that will be 

constructed instead average the climate in each area 

through time. The sampling areas are all in the same 

basic weather pattern today, and the parallelism of 

past and present snowlines in southern Washington 

State (Porter, 1964) suggests that general climatic patterns have not changed drastically. If climatic change 

has been approximately concordant for the areas 

sampled, the rind curves are valid for comparison and 

correlation purposes.

The pluvial lake record of the Western United States 

indicates that precipitation during glacial times could 

not have been much less than that of the present interglacial (G. I. Smith, oral commun., 1977). Similar

precipitation and colder temperatures would have 

resulted in greater effective soil moisture in glacial 

times than in interglacial times. The effects of lower 

temperatures and the effects of higher effective soil 

moisture (or vice versa) on weathering-rind development are offsetting.

These arguments suggest that, if the actual rate 

curves could be plotted in detail, they probably would 

fluctuate around the average rate curves that will be 

presented, but the fluctuations probably would be 

small and concordant between curves.

The fact that the two curves in figure 17 indicate different rates of rind formation is reasonable because of 

differences in climate, rock type, and other variables 

between the two areas. Because factors affecting rinddevelopment rates are different for each area, a 

separate curve of rind thickness versus time will be 

developed for each sampling area in this study. The 

form of these curves will be the same as that for the 

dated model for West Yellowstone (fig. 17). The curves 

will be calibrated using one deposit in each area as a 

calibration point whose age will be independently inferred from other data. The resulting rate curves will then 

be used to estimate the ages of the other deposits in 

each area. The calibration procedure empirically 

eliminates the need to account for the variation due to 

factors other than time, assuming that these factors 

are reasonably constant within each area.

In the absence of independent numerical ages, the 

calibration point for each curve must be inferred by 

correlation. The ages of the deposits representing the 

last glacial maximum (oxygen-isotope stage 2) are 

known or inferred with greater certainty than those of

10 20 30

TIME (103 YEARS B. P.)

40

FIGURE 18. Conceptual models of the weathering-rind thickness versus time function. A, model used by Sernohouz and Sole (1966); B, 

conceptual model used in this study for early stages of rind 

development; C, simple log function, similar to A, used to approximate B. Rind thickness scale approximate.
28 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

any other deposits in the areas sampled. Numerical age 

estimates exist for some of these deposits, and their 

correlation is relatively straightforward. However, 

these deposits were unsuitable for use as calibration 

points for the following reasons: (1) the uncertainty of 

individual rind measurements (±0.1-0.2 mm) is of the 

same magnitude as the average rind thickness for 

these deposits (0.1-0.4 mm), and (2) the age of these 

deposits is relatively close to zero, so that a small 

uncertainty in their position as a calibration point 

results in large uncertainty in the position of the rest 

of the curve.

A more useful calibration point is the deposits representing the glacial maximum about 135,000-140,000 

yr ago, just prior to the last interglaciation. These 

deposits correspond to oxygen-isotope stage 6, and to 

dated times of glacial maxima in Hawaii (Porter and 

others, 1977) and at West Yellowstone (Pierce and 

others, 1976). Most oxygen-isotope records indicate 

that ice volumes during stage 6 were at least as great 

as those during any time since. (For example, see 

fig. 20.) Therefore, it seems reasonable that moraines 

or terraces representing stage 6 should be preserved in 

most areas, although exceptions are known (for example, Pierce, 1979). Deposits of about this age also 

appear to have a minimum percent-error in weatheringrind measurements, and are near the middle of the 

apparent useful range of rind thickness (table 2); they

are thus a convenient calibration point. We have 

assigned this age to a number of sampled deposits 

based on soil development, morphology, sequence of 

deposits, loess distribution, terrace heights, and other 

relative-age indicators (table 6), in addition to 

stratigraphic relations. These data are primarily those 

described by previous workers in each of the study 

areas (references, fig. 3), supplemented by our own 

observations.

On the basis of the criteria listed in the preceding 

paragraph, the following deposits are considered correlative: Bull Lake at West Yellowstone, Bull Lake 

near McCall, Indian John in the Yakima Valley, preTahoe near Lassen Peak, and Donner Lake near 

Truckee. These correlations appear to be relatively 

sound, but correlations in the Puget Lowland and near 

Mount Rainier are less certain for reasons that will be 

discussed later, in the section on correlations. Two 

interpretations will be presented for these areas, corresponding to a calibration age of either early Wisconsin (65,000 yr) or pre-Wisconsin (140,000 yr) for the 

Salmon Springs and the Hayden Creek deposits.

The correlations used for calibrating ages are for the 

most part consistent with the opinions of previous 

workers in these areas, as expressed both in the original references (fig. 3) and in later communications 

(S. C. Porter, written commun., 1976; K. L. Pierce, 

written commun., 1976; P. W. Birkeland, written comTABLE 6. Characteristics of deposits considered to be about 140,000 yr old (oxygen-isotope stage 6)

[Starred entries, observations of authors; other entries from references, figure 3]

Area 

(MAT, MAP) 1

Uast- Yol 1 r\\j 

stone (1.7, 

50). 

McCall 

(4.4, 65). 

Yakima Valley 

(7.9, 55).

(6.0, 80).

(7, 120). 

Mt. Rainier 

(9, 130). 

Puget Lowland 

(10, 150).

Depth of 

Deposit oxidation 

(m)

Bull Lake *l-2

 do *2

Indian John 1-3+ 

(Porter, 1975).

Hayden Creek3 2 

Salmon Springs3 3

Maximum 

hue Bt horizon

7.5-WYR Moderately 

developed, 

15-30 cm thick. 

*5-7.5¥R Well developed, 

50 cm thick. 

7.5YR Well developed, 

20-30 cm thick,

7.5YR Well developed, 

50 cm thick.

5YR Well developed 

7.5-lOYR Weakly developed 

7.5YR Well developed(?)*

Loess2

0.3-1 m

(b).

Locally 2 m* 

(b). 

1-3 m 

(b).

Locally 

>3 m (b?).* 

Up to 6 m 

locally.*

Morphology

Subdued.*

Very 

subdued.* 

Do.

subdued. 

Subdued.

Very 

subdued.

1 MAT, mean annual temperature (°C); MAP, mean annual precipitation (cm).

2 (b), buried soil at least as well developed as the surface soil is locally recognizable beneath loess. 

3 An optional interpretation, discussed later, is that Hayden Creek and Salmon Springs deposits are early 

Wisconsin (60,000-70,000 yr) in age.
WEATHERING-RIND DEVELOPMENT AND TIME 29

num., 1976; D. R. Crandell, oral commun., 1976). Crandell and Miller (1974) favored a latest pre-Wisconsin 

age for the Wingate Hill Till, an age that appears to be 

too young based on its very thick weathering rinds. 

Crandell (1972) implied that Tahoe Till at Lassen Peak 

could be either early Wisconsin or latest pre-Wisconsin; we consider either correlation possible, but favor 

assigning the pre-Tahoe to the latest pre-Wisconsin.

Weathering-rind thickness versus time curves were 

constructed for each area (fig. 19), using the inferred 

ages of the deposits discussed above as calibration 

points (one point per curve). The logarithmic form of 

the curves is based on the model for the dated West 

Yellowstone sequence (fig. 17). The West Yellowstone 

curve appears in figure 19 as it did in figure 17, and 

each of the other curves was obtained by simply 

multiplying the West Yellowstone curve by a rate factor (table 7) so that it would pass through the appropriate calibration point. For example, the Bull Lake 

deposits at West Yellowstone, average rind thickness 

0.78 mm, are correlated with the Indian John deposits 

in the Yakima Valley, average rind thickness 1.05 mm. 

The Yakima Valley curve was obtained by multiplying 

the West Yellowstone curve by 1.05/0.78, or 1.35. The 

rate factor of 1.35 accounts for the difference in the 

rate of rind formation between West Yellowstone and 

the Yakima Valley, and for the difference in rind 

thickness between Bull Lake and Indian John 

deposits, which are thought to be about the same age. 

Finally, the rind thicknesses for the other deposits in 

each area were plotted on the curve constructed for 

that area.

Thus, the numerical age of one deposit in each area 

has been inferred using multiple correlation methods 

and stratigraphic relations, and the ages of the other 

deposits have been estimated from weathering-rind 

curves. The ages estimated by this method for the 

glacial deposits from the different areas of this study 

appear to be concentrated in discrete time intervals, indicated by the histogram in figure 19.

The usefulness of weathering rinds as a dating 

technique decreases towards both ends of the time 

scale in figure 19. For young ages, the method is 

limited by the ability to measure very thin rinds. The 

thinnest rinds that could be measured using the procedures in this study were 0.1 mm thick, which limits 

the usefulness of the method for deposits less than 

about 10,000 yr old. The decreasing rate of change 

with time implied by the logarithmic form of the 

weathering-rind curves limits the ability of 

weathering-rind thickness to discriminate between 

older deposits. In addition, few deposits older than 

about 0.5 m.y. in the Western United States have wellpreserved weathering profiles. Consequently, the use

TABLE 7. Deposits used as calibration points, and derivation of 

the rate of factors used in the weathering-rind equation 

d=alog (0.73+0.038t)

Deposit used for calibration

W. Yellowstone Bull Lake 

Me Call Bull Lake 

Age 

(103

yr)

140 

140 

140 

140 

iAn

Rind 

thickness 

(mm)

0.78 

1.61 

1.05 

1.06

.01

Rate 

factor 

(a) 2

1.00 

2.06 

1.35 

1.36

1 .1 Q

Hayden Creek (option 1) 65 1.37 2.71

Hayden Creek (option 2) 140 1.37 1.76

Salmon Springs (option 1) 65 1.01 2.00

Salmon Springs (option 2) 140 1.01 1.29

Lake deposits near West Yellowstone are about 

140,000 yr old, based on combined obsidian hydration and 

K-Ar methods (Pierce and others, 1976). Other deposits are 

inferred to be the same age based on relative-age methods 

and stratigraphic relations. The Hayden Creek and the 

Salmon Springs deposits may be younger than 140,000 yr; if 

so they are probably early Wisconsin (about 65,000 yr old).

2Rate factors are derived from the calibrated West 

Yellowstone curve. Rate factors are computed by dividing 

the rind thickness for a given deposit by the rind thickness 

for the equivalent age at West Yellowstone.

of weathering rinds for age estimates is generally 

limited to deposits younger than about 0.5 m.y., 

although weathering rinds may be useful in separating 

different ages of deposits up to about 1.0 m.y. if 

relatively stable (uneroded) sites can be found.

The curves in figure 19 are a major result of this 

study. Before discussing the conclusions that can be 

drawn from the curves, it seems appropriate to review 

the assumptions upon which the curves are based. 

These assumptions include (1) that in each sampling 

area, the sampling procedures, and the mapping upon 

which the sampling plan was based, produce 

measurements that are representative of the principal 

ages of deposits present, (2) that factors other than age 

are relatively constant throughout each sampling area, 

(3) that the form of the curves for rind thickness versus 

time based on the West Yellowstone data is correct 

and can be applied to other areas, and (4) that the age 

estimates and correlations used for calibration are correct. All of the conclusions based on the weatheringrind curves are qualified by the validity of these 

assumptions; however, these assumptions appear to be 

reasonable based on the evidence presented earlier.

The rind thickness versus time curves are presented 

not because we are absolutely sure that they are correct, but to provide a reasonable model that can be 

tested. Because of the consistency of the rind 

measurements, we believe that approximations of the 

numerical ages of the different deposits are contained
30 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

i I i I i I i I i I i I i I i I i I I I i I i

3.0

28

2.8

2.4

2.2

2.0

1.8

1.6

1.4

1 2

1.0

0 8

08

0.4

0.2

0

2.0

1.8

1.6

1 4

1.2

1.0

0 8

0.6

0 4

0.2

0

Option 1'

Rainier (130)

8-

i i i i

i i

C40 60 80 100 120 140 160 180 200 220 240 260 280 300

TIME (103 YEARS B.P.)

FIGURE 19. Weathering-rind thickness versus time curves for each of the principal sampling areas. A, areas 

containing andesitic rocks; B, areas containing basaltic rocks. Numbers in parentheses after area name 

are the approximate mean annual precipitation (cm) for that area. Calibration points (solid symbols) for 

West Yellowstone are based on obsidian hydration ages by Pierce and others (1976); other calibration 

points are by correlations to deposits of known age. Open symbols represent deposits plotted on the rind 

curves according to their mean rind thickness. Because of uncertainties as to the age of the Hayden 

Creek and the Salmon Springs deposits, which were used as calibration points, two interpretations (options 1 and 2) are presented for the Puget Lowland and Mount Rainier areas. Different symbol shapes 

correspond to different sampling areas. C, histogram of age estimates. Dashed, unshaded areas represent estimates from both options for the Puget Lowland and for Mt. Rainier, and thus include two 

estimates for each deposit.
REGIONAL CORRELATIONS 31

in the rind data; although independent numerical age 

estimates do not at present exist to test our model, 

they may in the future. We feel an obligation to offer a 

model that may make it possible to extract the age information from the rind data and to offer age estimates 

for different deposits in the sequences studied.

A number of independent observations can be made 

from figure 19 that support both the method used to 

construct the curves and the assumptions upon which 

the method is based. First, the ages determined from 

the weathering-rind curves for the last major glacial 

advance in each area generally are consistent with 

radiocarbon age estimates for those advances. Second, 

the curves show that the rate of weathering-rind formation generally increases with increasing mean annual precipitation. An exception is in the Puget 

Lowland, where the basalt is significantly different 

from other basalts used in the study (see Appendix C). 

Finally, the pattern of times of glacial advance, shown 

by the histograms in figure 19, is consistent with most 

marine oxygen-isotope records (fig. 20).

REGIONAL CORRELATIONS BASED ON

AGES ESTIMATED FROM

WEATHERING-RINDS

The data in figure 19 can be transformed easily into a 

correlation chart (fig. 21) by simply labeling the data 

points. Some of the correlations in figure 21, however, 

are in conflict with earlier interpretations. The following discussion examines those conflicts, along with 

other pertinent conclusions concerning the ages of the 

deposits. The deposit names used in this discussion are 

those used by previous workers and are used primarily 

to identify specific deposits. The conclusions and correlations we suggest apply to the deposits we sampled, 

but not necessarily to all deposits to which a given 

name has been applied.

CASCADE RANGE-PUGET LOWLAND

Weathering-rind methods do not resolve the age difference between the Evans Creek advance from Mount 

Rainier and the Vashon advance of the Cordilleran ice 

sheet. Stratigraphic relations between deposits related 

to the two advances demonstrate that the Evans Creek 

advance is somewhat older than the Vashon advance 

(Crandell, 1963), whereas the weathering-rind data, if 

anything, suggest the reverse. The discrepancy is 

probably due to differences in the rocks and climate of 

the two areas and to the inability of weathering rinds 

to resolve differences of only a few thousand years. The 

numerical age estimates of Crandell and Miller (1974, 

table 3) are retained for the two advances.

Considerable controversy persists regarding the correlation of all but the youngest glacial advances in the 

Puget Lowland-Cascades area (for example, Porter, 

1976). Much of this controversy results from difficulties in interpreting very old (50,000 yr or more) 

radiocarbon ages, and from differing concepts of the 

amounts of weathering and morphologic change expectable from the range of deposits of Wisconsin age. 

In addition, strong climatic gradients, variability of 

rock types, and variable thickness and extent of eolian 

mantles in the area make the interpretation of most 

relative-age criteria extremely difficult. These factors 

also hinder the interpretation of weathering-rind data, 

but weathering rinds are probably at least as good as 

any other age criterion available for determining the 

ages of deposits near or beyond the limit of the radiocarbon method. The following discussion examines the 

problems of age estimates in the Puget Lowland and 

the Cascade Range (including the Mount Rainier area 

and the Yakima Valley) and discusses the correlations 

between these areas. We will present the interpretations that we favor, from weathering-rind thickness 

and other weathering data.

Crandell and Miller (1974, p. 55-56) favored a 40,000 

to 80,000 yr age (oxygen-isotope stage 4) for the Hayden Creek advance and suggested that the Wingate 

Hill advance occurred just before 125,000 yr ago (during oxygen-isotope stage 6). Hayden Creek deposits exhibit large variations in weathering-rind thicknesses 

between sites (Appendix A), due in part to burial by 

eolian deposits at some sites and to erosion at others. 

Sites C76-40 and C78-116 were chosen as representative of the weathering interval since Hayden Creek 

time, because they were the only stable, loess-free sites 

examined. Rinds at these sites, which are several 

kilometers upvalley from the Hayden Creek terminus 

(Crandell and Miller, 1974, pi. 1), average 1.37 mm on 

fine-grained andesite.

In general, the soils in Hayden Creek deposits contain 10 YR to 7.5 YR colors, and a weakly developed 

argillic B horizon. Locally, these deposits are covered 

by thick (>2 m) eolian deposits (loess?), which are reddish (7.5YR), clayey, and weathered to depths of more 

than 2 m. We did not find any unambiguous exposures 

of a buried soil beneath the surface loess on Hayden 

Creek deposits, but the overall weathered appearance 

of the loess may make it difficult to recognize a buried 

soil. However, the following facts indirectly suggest 

that a buried weathered zone may exist beneath the 

loess on Hayden Creek deposits: (1) locally, the 

presence of relatively thick weathering rinds (as much 

as 1.0 mm average) beneath loess more than 2 m thick, 

(2) rapid lateral variation in weathering-rind thickness 

beneath the loess in places, suggesting erosion of a 

weathered zone, and (3) the common occurrence of a 

zone of increased compaction (Bt horizon?) near the
32 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES 

100 200 300 400 500 600 700

STAGES

100 200 300 400

TIME (103 YEARS B.P.)

500 600 

_i_

700

1| 2| 3 . a 5 e 6 7

4

1 ,l3lla,<

245

$ 6 7 £

1| 2 | 3 |4|a 5

8 9 |10| 11 12 13 | 14 15 16 17 18 1 9$2Q$^2 !1^^22^fS23\|

i

1 91 |11|12|13|14| 15 16 , 18 ||RN8fc22$23$

10

el 6 I

17 192021

7 8 | 9 10 | 11 | 12 | 13 | 14 |

1121

i

o 1 [ _

4

5 e 6

i i

7 8 9 10 | 11 |12| 13 |,| 15 |16| 17 |18£ £

I i i i i i i ^ i i i i

V28-238 

V28-239 

V12-122

P6304-9

6789

DEPTH, IN METERS

10 11 12 13 14 15

FIGURE 20. Comparison of ages estimated from weathering rinds in glacial deposits in this study with the deep-sea oxygen-isotope record. A, 

ages of glacial deposits estimated from figure 19. Error bars on ages were obtained by projecting ±1 standard deviation of the 

weathering-rind measurements to the curves in figure 19. Closed circles are the calibration points of figure 19, whose ages are known from 

independent age estimates or are inferred by correlation; open circles represent ages estimated from weathering-rind thicknesses (fig. 19). 

Numbers at the ends of the error bars refer to the optional interpretations for the Puget Lowland and Mount Rainier areas in figure 19. B, 

oxygen-isotope records of four deep-sea cores (V28-238 and 239, Shackleton, 1977a; V12-122, Broeker and van Donk, 1970; and P6304-9, 

Emiliani, 1966). The isotope records have been plotted on a common time scale according to the estimated ages of stage boundaries given 

by Hays and others (1976) for stages 1 to 13, and by Shackleton and Opdyke (1973) for stages 13 to 20. Shaded portions of the curves 

represent isotope values heavier than an arbitrary value (the low value of stage 2 plus 25 percent of the difference between stage 1 and 

stage 2). the shaded areas are intended to highlight times of high ice volumes. C, The four cores plotted on a common depth scale, with the 

oxygen-isotope stages numbered. Shaded portions are those that are magnetically reversed (below the Brunhes- Matuyama boundary (arrow in C, and long dash-short dash line in B)).
REGIONAL CORRELATIONS 33

2

3

4

5 

6

7 

8

10

15

Z 2°

CD 

30

I"

£ 50 

m 60 

 0 70 

" 80

UjlOO

2

H- 150 

200

300

400 

500 

600 

700 

800

1000

WEST 

-YELLOWSTONE

Deckard Rats

Pinedale

=\ Bull Lake

McCALL

Pinedale 

Pinedale

Intermediate

Bull Lake

Outer Bull Lake

 4- ?

Pre-Bull Lake

YAKIMA 

VALLEY

Domerie

Ronald

Bullfrog

Indian John

Swauk Prairie

 h 

Thorp

Pre-Thorp(?)

LASSEN PEAK

Tioga 

?

 f 

"Early Tioga"

 t 

Tahoe

Pre-Tahoe

? 

t

Pre-Tahoe

I 

?

TRUCKEE

Tioga 

Tahoe

Donner Lake

? 

t

Hobart

?

PUGET

OPTION 1

.OWLAND 

OPTION 2

Vashon 

Low Fraser terrace

High Fraser |

Salmon 

\ Springs

 

?

Helm Creek

Wedekind 

Creek

High Fraser 

terrace /

Salmon Spgs

Helm Creek

Wedekind 

Creek

MOUNT

OPTION 1

RAINIER 

OPTION 2

Vashon 

Evans Creek _

Hayden Cr

f Wingate \ 

Hill

Logan Hill

Hayden Cr -^

 ~

Wingate ~

^__H!!!_-2 

Logan Hill 

FIGURE 21. Correlation chart for deposits sampled in this study. The chart was produced from the age estimates in figure 19. Horizontal lines 

enclose deposits thought to be about the same age. Arrows suggest other possible correlations, queried where uncertain, discussed in the 

text. Stratigraphic names are those of previous workers. (See fig. 3 for references.) Vashon deposits (Mount Rainer) are slightly younger 

than Evans Creek deposits (Crandell, 1963); weathering-rind thicknesses are not consistent with this difference. Rinds in Swauk Prairie 

deposits are only slightly thicker than those in Indian John deposits. However, Swauk Prairie deposits are thickly mantled with loess, 

and therefore may be significantly older than the rind thickness suggests (S. C. Porter, oral commun., 1977). Pre-Tahoe deposits at Lassen 

Peak probably include deposits of more than one age. Rinds were measured only for the youngest (innermost) of these deposits.

base of the loess. Although the soils and weathering 

characteristics of the Hayden Creek deposits vary considerably due to the eolian mantle and to erosion, no 

systematic change suggestive of discrete ages within 

the Hayden Creek was noted.

In estimating the age of the Hayden Creek advance, 

the rind thicknesses of both younger (Evans Creek) 

and older (Wingate Hill) deposits and also the fact that 

the rate of rind development decreases with time must 

be considered. Because weathering rinds are so thick 

(and soft) an Wingate Hill deposits (>3.0 mm average), 

Crandell and Miller's (1974) correlation of the Wingate 

Hill deposits with isotope stage 6 (about 140,000 yr 

old) implies an extremely rapid rate of weathering rind 

development. This rate is not supported by the very 

thin rinds (0.1-0.2 mm) on Evans Creek deposits. 

Because the age of the Wingate Hill deposits is uncertain but probably much greater than 140,000 yr, the 

data for the Hayden Creek deposits were used for the 

calibration points in figure 19. Two interpretations (options) of the age of the Hayden Creek deposits are 

shown in figure 19: (1) early Wisconsin (about 65,000 

yr old) as suggested by Crandell and Miller (1974) and 

(2) latest pre-Wisconsin (about 140,000 yr old).

An age of 140,000 yr for the Hayden Creek deposits 

(fig. 19, option 2) is considerably older than Crandell 

and Miller's (1974) estimate, and it leaves the much 

less extensive Evans Creek end moraines as the sole 

representative of the Wisconsin Glaciation. However, 

this option is favored by (1) the thickness (1.37 mm 

average) of weathering rinds at the few undisturbed 

sites sampled on the Hayden Creek deposits, (2) the 

large ratio, about 9:1, in weathering-rind thickness between the Hayden Creek and the Evans Creek deposits 

(table 2; fig. 12), (3) the development of an argillic B 

horizon on the Hayden Creek deposits, in contrast to 

the lack of clay enrichment in the weak soil on the 

Evans Creek deposits, (4) thick, weathered loess on 

some Hayden Creek deposits, and (5) some suggestion 

of a buried weathering zone beneath the loess on 

Hayden Creek deposits.

On the other hand, if the Hayden Creek deposits are 

about 65,000 yr old (isotope stage 4), then the Wingate 

Hill deposits must be 250,000 or more yr old, if the rate 

of weathering-rind formation is logarithmic. These 

ages imply the absence of any recognized glacial 

deposit (end moraine or outwash terrace) representing 

an advance about 140,000 yr ago; this advance appears
34 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

to be widely represented elsewhere. In addition, an age 

of about 65,000 yr (isotope stage 4) for the Hayden 

Creek deposits leads to the conclusion that the glacial 

advance representing isotope stage 4 was nearly twice 

as extensive as that representing isotope stage 2 

(Evans Creek). However, Crandell and Miller (1974) 

favored an early Wisconsin age for the Hayden Creek 

deposits, primarily because of the weak development 

of an argillic B horizon, and correlation with the 

Salmon Springs deposits in the Puget Lowland, which 

were thought to be early Wisconsin.

In summary, the age of the Hayden Creek 

advance(s?) remains unresolved but is probably either 

about 65,000 or 140,000 yr. The possibility remains 

that the Hayden Creek deposits include deposits of 

both ages, but no data supporting this hypothesis have 

been found. Based on weathering data, an age of about 

140,000 yr rather than 65,000 yr seems more probable. 

The Wingate Hill deposits are surely pre-Wisconsin, 

and are probably much older than 140,000 yr. If the 

Hayden Creek deposits are about 140,000 yr old, then 

our rind development curve (fig. 19) places Wingate 

Hill at more than a half million years old.

An analogous situation exists in the Puget Lowland, 

where the age of the Salmon Springs Drift is the subject of controversy. Traditionally, it has been considered early Wisconsin (Birkeland and others, 1970), 

but Porter (1976) suggested that it could tfe preWisconsin, at least in part. The arguments for these 

alternative interpretations are much the same as those 

presented earlier for the Hayden Creek deposits. One 

difference between the two areas is that the Salmon 

Springs and Vashon advances were similar in size, 

whereas the Hayden Creek and Evans Creek advances 

were markedly different in extent.

Salmon Springs Till appears to have a moderately 

well developed argillic B horizon and has weathering 

rinds about 1 mm thick on basalts. It is commonly 

capped by thin, weathered eolian deposits, and both 

the till and eolian deposits are oxidized to 7.5YR colors. On the other hand, the equivalent outwash terrace 

(middle Salmon Springs; Carson, 1970) is covered by 

thick, relatively unweathered eolian deposits (loess?), 

locally as much as 6 m thick. The gravels at the gravelloess contact are oxidized, but in most places the oxidation appears to be ground-water alteration rather 

than a buried soil. At one locality (C76-37B) on the terrace margin where the loess is thin, weathering rinds in 

the gravel are comparable to those on stones in Salmon 

Springs Till (1.07 mm average thickness).

The Puget Lowland receives considerably more precipitation than the other sampling areas in this study, 

but the basalt in the deposits there contains almost no 

olivine or vitric glass, and therefore it probably

weathers more slowly than the basalt in other areas 

sampled. The net effect of these rock type and 

precipitation factors on weathering-rind-development 

rates is uncertain, but the two factors have opposite effects, and thus tend to cancel each other. In any case, 

average rind thicknesses on stones from the Salmon 

Springs deposits are about the same as those on stones 

from deposits considered to be 140,000 yr old in the 

Yakima Valley. The latter area receives one-half to onethird as much precipitation as the Puget Lowland but 

contains basalt that apparently weathers faster than 

that in the Salmon Springs deposits.

Two buried drifts are exposed in the type section of 

the Salmon Springs Drift. The relation of the Salmon 

Springs surface till examined in this study to the two 

drifts in the type area is uncertain. The two drifts in 

the type area are separated by a peat tentatively 

estimated to be about 50,000 yr old on the basis of 

radiocarbon determinations (Crandell and Miller, 1974, 

p. 18). However, a more recent determination of about 

71,500 yr has been obtained by 14C enrichment techniques (Stuiver and others, 1978). No evidence was 

found, either in this study or in Carson (1970), to suggest that more than one age of Salmon Springs Till exists at the surface. Carson also argued against an 

earlier, less extensive Salmon Springs advance being 

represented by one of the multiple outwash terraces 

emanating from the Salmon Springs Till margin. He 

argued that the three terraces are related to one main 

Salmon Springs advance, a recessional stage of that 

advance, and a slightly older advance from the Olympic Mountains.

Marine deposits in the area of Gray's Harbor, Wash., 

provide useful information concerning the age of the 

Salmon Springs deposits. Three sampling sites on the 

first marine terrace, about 20-25 m above sea level, 

produced an average weathering-rind thickness of 

0.79±0.42 mm, although basalts in these deposits 

were scarce and the measurements ranged more widely 

than those for most other sample sites. These deposits 

have not been mapped or studied in detail, and sea 

level curves for areas this close to the continental ice 

margin are different from those for areas where high 

sea stands have been dated. However, it seems unlikely that the terrace sampled could be younger than the 

last series of high sea stands, associated with isotope 

stage 5 (see fig. 20). At Willapa Bay, about 60 km 

south of Gray's Harbor, Kvenvolden and others (1977) 

suggested that the first (20-m) marine terrace is 

Sangamon in age based on amino acid enantiomeric 

ratios. In addition, samples we collected of clayey 

deposits overlying the lower Salmon Springs Terrace 

near Grays Harbor have pollen spectra suggestive of 

an interglacial climate (L. E. Heusser, oral commun.,
REGIONAL CORRELATIONS 35

1979). These data suggest that Salmon Springs deposits, with an average rind thickness of 1.01 ±0.40 

mm, may be older than the last interglaciation and the 

first marine terrace, and thus may be about 140,000 yr 

old.

Two different interpretations (options) of the 

chronology in the Puget Lowland are presented in 

figures 19 and 21. The similarity in weathering data for 

the Hay den Creek and the Salmon Springs deposits 

suggests that the two are at least partially equivalent. 

We interpret the available data as favoring an age of 

about 140,000 yr (option 2) rather than 65,000 yr (option 1) for both of these deposits.

In the Yakima Valley, Porter (1976) considered all 

members of the Lakedale Drift (Hyak, Domerie, 

Ronald, and Bullfrog Members) to be late Wisconsin, 

equivalent to the Vashon and Evans Creek advances 

on the other side of the Cascades. He also considered 

the Kittitas Drift (Indian John and Swauk Prairie 

Members) to be pre-Wisconsin (written commun., 

1976) and to correlate with the Salmon Springs Drift; 

hence he suggested that the latter may be preWisconsin at least in part (Porter, 1976). A preWisconsin age for the Kittitas Drift is strongly supported by evidence based on soil development, buried 

soils, loess stratigraphy, morphology, terrace profiles, 

and position of this drift in the stratigraphic sequence. 

These data also suggest that the younger of the two 

Kittitas members (Indian John) is latest pre-Wisconsin 

in age, or about 140,000 yr old. Relative-age criteria for 

the Indian John deposits are very similar to those of 

the 140,000-yr-old Bull Lake deposits at West Yellowstone (table 6).

Porter (1976) grouped the two members of the Kittitas Drift because they have similar weathering and 

erosional characteristics. Weathering rinds on stones 

in the Swauk Prairie Member are only slightly thicker 

than those on stones from the Indian John Member. 

However, Porter (1976; oral commun., 1977) also indicated that the Swauk Prairie Member may conceivably be at least one full glacial cycle (about 105 yr in the 

marine record) older than the Indian John Member. If 

that is the case, then the rinds in the Swauk Prairie 

Member are anomalously thin, probably due to burial 

by a thick mantle of loess. Data that suggest a major 

age difference between the Swauk Prairie and Indian 

John Members include the following: (1) Our observations suggest that the Swauk Prairie Member locally 

may contain two buried soils (one in the till and one 

within the overlying loess) indicating three episodes of 

weathering separated by two episodes of loess deposition. No more than one buried soil was observed 

associated with the Indian John Member. (2) The 

Swauk Prairie terrace is twice the height of the Indian

John terrace above present drainage and is more than 

25 m above the level of the Indian John terrace.

Differences in weathering-rind thickness indicate 

that significant age differences exist between the 

members of the Lakedale Drift. The three older 

members (Domerie, Ronald, Bullfrog) have average 

rind thicknesses differing by factors of about 1, 2, and 

3 (0.25, 0.52, 0.71 mm) respectively. As discussed 

earlier, the rate of weathering-rind development 

decreases with time, so the three members must differ 

in age by factors of more than 1,2, and 3, respectively. 

Therefore, because the Domerie Member is about 

14,000 yr old (Porter, 1976), the three members probably span the entire time of the last glaciation, and the 

Bullfrog Member probably dates from early in that 

glaciation (early Wisconsin).

CALIFORNIA MOUNTAINS

Tahoe and Tioga deposits traditionally have been 

considered to be early and late Wisconsin in age, 

respectively (Birkeland and others, 1970). The 

weathering-rind data suggest that, for two areas examined in this study, these previous interpretations 

need to be reexamined. In the Truckee, Calif., area, 

Tahoe deposits have only slightly thicker rinds than 

Tioga deposits. Soils and other weathering data for the 

two deposits are also similar according to recent work 

by Burke and Birkeland (1979). They have now considered much of what was originally mapped as Tahoe 

(Birkeland, 1964) to be equivalent to Tioga, so that 

much of what was previously mapped as Tahoe near 

Truckee may not be correlative with Tahoe deposits 

mapped elsewhere in the east-central Sierra Nevada 

region. However, Burke and Birkeland (1979) have also 

discovered a more intensely weathered deposit that 

could be early Wisconsin. Weathering-rind thicknesses 

measured by Burke (1979) for this deposit appear to be 

similar to those of Donner Lake deposits. Thus, this 

newly recognized deposit in the Truckee area that is 

possibly intermediate in weathering characteristics 

and age between the Tioga and the Donner Lake may 

be the equivalent of the Tahoe of the east-central 

Sierra Nevada.

In the Lassen Peak area, deposits originally mapped 

as Tahoe by Crandell (1972) were subdivided into 

Tahoe and "early Tioga" by Kane (1975). This subdivision appears to be valid because the two deposits 

were shown to have distinctly different soil colors, 

depths of oxidation, and weathering-rind thicknesses. 

The weathering-rind data presented here suggest that 

the Tahoe deposits of this area are early Wisconsin, 

and the "early Tioga" deposits are intermediate between late and early Wisconsin (fig. 19).
36 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

The Tahoe deposits near Lassen Peak could possibly 

be pre-Wisconsin (Crandell, 1972), but this interpretation creates several problems. First, a pre-Wisconsin 

age for the Tahoe would demand an exceptionally slow 

rate of weathering-rind formation (fig. 19). This rate 

would be anomalous considering the large amount of 

precipitation in the Lassen Peak area. No lithologic 

reason was noted that could account for such a slow 

rate of rind formation. Second, a pre-Wisconsin age for 

the Tahoe (and the Wisconsin age of the "early Tioga") 

would place the last interglacial within what Crandell 

(1972) mapped as a single unit (Tahoe). Crandell (1972) 

recognized that his Tahoe unit probably contained 

deposits of more than one age, but evidently considered other age differences to be more important. 

Therefore, although characteristics such as subdued 

morainal form, oxidation to more than 1 m, and 7.5 YR 

colors suggest that the Tahoe at Lassen Peak could be 

as old as the Bull Lake deposits at West Yellowstone, 

we consider the Tahoe deposits at Lassen Peak to be 

early Wisconsin in age. The wetter climate at Lassen 

Peak appears to increase the rate at which weathering 

and erosional characteristics are attained.

Cursory observations of weathering and erosional 

features suggest that pre-Tahoe deposits in the Lassen 

Peak area could encompass more than one preWisconsin age. However, all pre-Tahoe sampling sites 

were located immediately beyond the limit of Tahoe 

deposits in order to sample the youngest deposit in 

case of multiple ages. Rind thicknesses from these 

sites suggest that the pre-Tahoe deposits sampled are 

latest pre-Wisconsin in age (about 140,000 yr old).

ROCKY MOUNTAINS

The age of the Bull Lake Glaciation has been the 

subject of considerable controversy because of the lack 

of numerical-age determinations. Also, correlations 

based on differing relative-age criteria in areas of differing climates and rock types have proved problematical. The term Bull Lake was originally defined by 

Blackwelder (1915) to designate the older, morphologically muted moraines of the two sets of well-preserved 

moraines at Bull Lake, Wyo., on the flanks of the Wind 

River Range. Since that time, a conceptual definition 

of the characteristics of Bull Lake deposits, based on 

terrace heights, moraine morphology, and soil development appears to have evolved. These characteristics 

were thought to represent an early Wisconsin to intraSangamon age (Richmond, 1965).

The belt of moraines that wrap around Horse Butte 

in the West Yellowstone Basin have been described as 

Bull Lake by all workers who have examined them 

(Pierce and others, 1976, references). Apparently, these

deposits fit the concept of the Bull Lake rather well, 

although no outwash terraces associated with the 

moraines are preserved in the subsiding West Yellowstone Basin. Problems of correlation and nomenclature 

arose when the deposits near West Yellowstone were 

dated at about 140,000 yr old by combined K-Ar and 

obsidian-hydration methods (Pierce and others, 1976). 

Obviously, this age is not compatible with an early 

Wisconsin age for the Bull Lake. Although Richmond 

(1976, 1977) has recently favored correlation of the 

West Yellowstone deposits with the late stade of the 

Sacajawea Ridge Glaciation, he stated (1976, p. 373) 

that "surficial and weathering characteristics***do 

not exclude possible correlation with the broad smooth 

moraines of the early stade of the Bull Lake as locally 

developed at Bull Lake." In addition, "type" Sacajawea Ridge deposits on the east side of the Wind 

River Range are associated with the 600,000-yr-old 

Pearlette "type-O" ash (Pierce, 1979). Also, Bull Lake 

deposits in the type area remain undated, and their correlation with deposits in other areas is uncertain. 

Therefore, the belt of moraines that wrap around 

Horse Butte are here called the Bull Lake deposits at 

West Yellowstone because of their well-established 

similarity to the type Bull Lake deposits. In view of 

the present conceptual difficulties, the use of the 

name Bull Lake for deposits near West Yellowstone 

and McCall does not necessarily imply that the conclusions reached for these deposits are applicable to all 

the Bull Lake deposits in the type area, or to all 

deposits mapped as Bull Lake in the Rocky Mountains.

In the McCall area, the pronounced development of 

an argillic B horizon and the thickness of the weathering rinds in most of the Bull Lake deposits strongly 

suggests that they are at least as old as the West 

Yellowstone Bull Lake. A younger age for the Bull 

Lake deposits at McCall would require an unreasonably rapid rate of weathering-rind formation (fig. 

19). However, small portions of the deposits at McCall 

mapped as Bull Lake by Schmidt and Mackin (1970) 

appear to be early Wisconsin. Weathering-rind measurements at sampling sites on the moraines mapped 

partly as the innermost of the large group of Bull Lake 

moraines and partly as the outermost of the Pinedale 

moraines were consistently thinner than those at sites 

on the rest of the Bull Lake moraines. The average rind 

thickness for these moraines (here called "intermediate") results in an age of about 60,000 yr on the 

McCall curve in figure 19.

Thus, in the two areas examined in this study, the 

deposits that have been mapped as Bull Lake and that 

fit the conceptual definition of Bull Lake, with the exception of the innermost moraine at McCall, evidently 

are pre-Wisconsin. This age is contrary to that usually
SUMMARY 37

assigned to the Bull Lake Glaciation (Richmond, 1965, 

1976; Birkeland and others, 1970). In addition, the Bull 

Lake-Tahoe correlation (Birkeland and others, 1970) 

appears to be uncertain because (1) most of the Bull 

Lake deposits examined in this study are believed to 

be pre-Wisconsin, although some deposits grouped 

with Bull Lake are probably early Wisconsin, and (2) 

the Tahoe deposits examined in this study are probably early Wisconsin or younger, although Tahoe 

deposits in some areas may be pre-Wisconsin (Burke 

and Birkeland, 1979).

SUMMARY

A large number of environmental factors, including 

climate, parent material, vegetation, position in the 

weathering profile, and time affect weathering-rind 

development, just as they do soil development and 

other near-surface weathering processes. Because the 

focus of this paper is on the influence of time, sampling 

procedures were designed to reduce, eliminate, or 

isolate the variation due to all the factors other than 

time.

Even though much of the variation in rind thickness 

due to factors other than time was eliminated, that remaining is clearly important, although difficult to 

evaluate quantitatively. Of the remaining variation, 

that due to lithologic variation in the rocks sampled 

appears to be the most important, even within the 

limited range of lithologies and textures studied. 

Variation in rind thickness due to differences in 

climate is also important, especially that due to differences in precipitation. The effect of temperature 

could not be evaluated independently; it may have a 

considerable influence on rind thickness. Variations in 

soil matrix texture, vegetation, and erosion and (or) 

deposition also contribute small amounts of variation 

in rind thickness.

More than 7,335 weathering-rind measurements at 

about 150 sampling sites in the Western United States 

were analyzed to demonstrate the usefulness of 

weathering-rind thickness as a relative-age criterion. 

Of the 17 areas examined, 7 had the most favorable 

rock types and climates and were studied in detail. 

Weathering-rind measurements can be closely reproduced by different workers if they adhere to the same 

procedures. The distribution of weathering-rind 

measurements at individual sites tends to be log normal, with a tendency for positive skewness. Within a 

sampling area, deposit age (the time factor) is by far 

the most important source of variation in weatheringrind thickness. All differences in mean rind thickness 

between stratigraphic ages within a sampling area are 

important. Differences in mean rind thickness between

moraines are generally negligible, whereas such differences between sites may be important, but are largely 

due to factors other than time. Therefore, weathering 

rinds are an excellent quantitative indicator of relative 

age.

Two approaches can be used to extract numerical 

age information from the weathering-rind data for a 

given area: (1) age constraints provided by rindthickness ratios, and (2) estimation of the precise rind 

thickness versus time function. With only few and 

minor assumptions, rind-thickness ratios can be used 

to determine with near certainty the minimum and 

maximum age ratios between two deposits. Thus, if 

the age of one deposit in a sequence is known or 

postulated, the minimum and maximum age of another 

unit can be determined. This ratio method, although 

not precise, provides both useful information on ages 

and constraints on correlations. Thus, even if a reader 

is unable to accept the assumptions necessary for the 

construction of our thickness versus time curves, more 

certain but less definitive information on age relations 

can still be obtained from the rind-ratio data (table 5).

A logarithmic model of weathering-rind development with time appears to be most consistent with the 

processes involved and with independent age controls. 

The rind thickness versus time curves (figs. 17, 19) are 

our best approximation of the age information contained in the rind-thickness data; they are presented as 

a model to be evaluated, refined, or rejected as more information on radiometric ages and rates of weathering 

processes is obtained.

The model of weathering-rind development with 

time, based on several assumptions, can be used to 

estimate numerical ages. On the basis of rind data for 

deposits of known age at West Yellowstone and in 

Bohemia, rind thickness increases with time according 

to a logarithmic function. Because of differences in 

rock type and climate, individual logarithmic curves 

were constructed for each area, using one deposit in 

each area as a calibration point. The ages of the calibration points in areas other than West Yellowstone were 

inferred by correlation using traditional relative-age 

methods and stratigraphic relations. The correlations 

are based on data from previous workers and on our 

own observations. The ages of all deposits other than 

the calibration points were estimated from the 

weathering-rind curves in figure 19.

The curves in figure 19 depend on a number of 

assumptions, including: (1) that the sampling procedures produced representative data, (2) that factors 

other than time are relatively constant within each 

sampling area, (3) that the form of the curves is correct, and (4) that the age estimates for the deposits 

used for calibration are correct. To the degree to which
38 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

these assumptions are valid, the model of weatheringrind development results in a number of important 

conclusions:

1. The Wisconsin Glaciation in the Western United 

States appears to be complex. Convincing 

evidence exists for a mid-Wisconsin glacial advance between about 35,000 and 50,000 yr ago in 

several areas, including West Yellowstone 

(Pinedale) and the Yakima Valley (Ronald). The 

"early Tioga" deposits in the Lassen Peak area 

appear to be younger than 35,000 yr, but are clearly older than the late-Wisconsin Tioga deposits. In 

the Puget Lowland, the high Praser terrace may 

represent a mid-Wisconsin advance from the 

Olympic Mountains. At West Yellowstone, this 

mid-Wisconsin advance was the largest one in 

Wisconsin time (Pierce and others, 1976). These 

advances are similar in age to the late Altonian advances in the midcontinent (Willman and Frey, 

1970; Dreimanis and Karrow, 1972).

2. Age estimates based on weathering rinds indicate an 

advance about 60,000-70,000 yr ago (early 

Wisconsin) in several areas, including the McCall 

area, the Yakima Valley, the Lassen Peak area, 

and possibly the Puget Lowland and Mount 

Rainier areas. This advance is probably correlative with oxygen-isotope stage 4 of the marine 

record, a time of high worldwide ice volumes.

3. In the seven principal areas examined in this study, 

the rind data (fig. 19) do not indicate any end moraines dating from the period between about 

75,000 and 130,000 yr ago, based on our age 

estimates, and the attendant assumptions. We 

found no stratigraphically distinct deposits with 

rinds in the range of 5-25 percent thinner than the 

deposits we correlate with oxygen-isotope stage 6. 

Lack of end moraines does not imply that glacial 

expansions did not occur during this interval 

75,000-130,000 yr ago, which is generally 

equivalent to stage 5 of the oxygen-isotope record, 

a time of relatively low worldwide ice volumes. 

Richmond (1976) identified and approximately 

dated glacial events in the Yellowstone area that 

he correlated with oxygen-isotope stages 5b and 

5d (fig. 20); however, these events are not directly 

related to preserved end moraines. On the basis of 

ice-contact features of the West Yellowstone 

rhyolite flow (R. L. Christiansen, written 

commun., 1972), glaciers were sizable 

115,000±7,000 yr ago (Pierce and others, 1976; 

Richmond, 1976). In the areas examined in this 

study, glacial advances during oxygen-isotope 

stage 5 apparently were not sufficiently extensive 

to leave a preserved end-moraine record.

4. Our correlations suggest that an advance about 

140,000 yr ago is widely represented. These correlations are based on traditional relative-age 

criteria, and are the basis for calibrating the 

weathering-rind model. However, the ages of the 

Hayden Creek and Salmon Springs deposits in the 

Mount Rainier-Puget Lowland area are uncertain. 

These deposits may date either from about 65,000 

or from about 140,000 yr ago; if they are 65,000 yr 

old, then no representatives of a 140,000-yr-old advance has been found in these areas. Weathering 

data and stratigraphic relations with interglacial 

deposits appear to favor an age of about 140,000 

yr for Salmon Springs and Hayden Creek. A 

widespread occurrence of glacial deposits about 

140,000 yr old is consistent with the marine 

oxygen-isotope record (stage 6), which indicates 

that worldwide ice volumes were at a maximum 

during that time. Most oxygen-isotope records indicate that ice volumes during stage 6 were equal 

to or greater than those of any subsequent time.

5. End moraines in some areas were deposited during 

times that are not represented by such features in 

other areas. This probably results from differences in glacier response due to local climatic 

variations in different areas, although it could 

result from inadequate sampling or from inadequate mapping on which the sampling was based. 

Deposits of one glacial advance may be preserved 

in some areas, or eroded or buried in others by a 

succeeding advance of about the same size, 

depending on relatively small differences in the 

response of the glaciers to local climatic conditions. As a result, correlation by sequence of 

deposits alone (finger-matching) will inevitably 

lead to errors.

The approximate ages estimated from weathering 

rinds conflict with some previous interpretations and 

agree with others. Weathering rinds appear to be particularly helpful in distinguishing early Wisconsin 

deposits from latest pre-Wisconsin deposits in many 

areas. Relatively few deposits older than 140,000 yr 

have weathering profiles preserved well enough to be 

useful for numerical age estimates from weathering 

rinds. The decreasing rates of weathering-rind formation with time also limits their use for very old 

(> 0.5 m.y.) deposits.

In the Mount Rainier-Puget Lowland area, Hayden 

Creek and Salmon Springs deposits are probably at 

least partially correlative, but whether they are early 

Wisconsin, pre-Wisconsin, or include both is uncertain. 

The available weathering and stratigraphic data favor 

a pre-Wisconsin age. Wingate Hill and Helm Creek
REFERENCESCITED 39

deposits are certainly pre-Wisconsin and are probably 

at least several hundred thousand years old.

On the east side of the Cascade Range, Kittitas Drift 

is almost certainly pre-Wisconsin, and the Indian John 

Member is probably latest pre-Wisconsin. The Lakedale Drift appears to span most of the Wisconsin, with 

the Bullfrog Member probably being early Wisconsin.

In the Sierra Nevada-southern Cascades region, 

Tahoe deposits at Lassen Peak appear to be at least as 

old as early Wisconsin, but the Tahoe sampled at 

Truckee is considerably younger, unlike most Tahoe 

deposits in the Sierra Nevada-southern Cascades 

region. The two areas sampled in this region contain 

some of the few deposits in the Sierra Nevada-southern 

Cascades that can be convincingly correlated with 

late pre-Wisconsin (Donner Lake and pre-Tahoe, 

respectively).

In the Rocky Mountains, most deposits mapped and 

commonly accepted as being Bull Lake at McCall and 

West Yellowstone are pre-Wisconsin in age. A moraine 

intermediate between the Pinedale and the Bull Lake 

moraines at McCall is probably early Wisconsin. 

Pinedale deposits at West Yellowstone are somewhat 

older than the late Wisconsin Pinedale deposits at 

McCall.

In conclusion, weathering rinds have been shown to 

be an excellent indicator of relative age. As is the case 

with all relative-age criteria, factors other than time 

cause variation in rind thickness. However, time is 

much more important than any other factor in determining rind thickness. With weathering rinds, variation due to factors other than time is easier to isolate, 

account for, or eliminate than with many other 

relative-age criteria. By calibrating the curves of 

weathering-rind thickness versus time with independent age estimates, the influence of factors other than 

time can be eliminated, and weathering-rind thickness 

can be used to estimate the numerical ages of deposits. 

The wide applicability of weathering rinds and the 

numerical age estimates that can be made from them 

make weathering rinds a useful correlation tool for 

Quaternary deposits in the Western United States.

REFERENCES CITED

Alden, W. C., 1953, Physiography and glacial geology of Western

Montana and adjacent areas: U.S. Geological Survey Professional

Paper 231, 200 p. 

Anderson, R. L., and Bancroft, T. A., 1952, Statistical theory in

research: New York, McGraw-Hill, 399 p. 

Arkley, R. J., 1963, Calculation of carbonate and water movement in

soil from climatic data: Soil Science, v. 96, no. 4, p. 239-248. 

Benedict, J. B., 1973, Chronology of cirque glaciation, Colorado Front

Range: Quaternary Research, v. 3, no. 4, p. 584-599. 

Birkeland, P. W., 1963, Pleistocene volcanism and deformation of the

Truckee area, north of Lake Tahoe, California: Geological Society of 

America Bulletin, v. 74, no. 12, p. 1453-1464.

.1964, Pleistocene glaciation of the northern Sierra Nevada,

north of Lake Tahoe, California: Journal of Geology, v. 72, no. 6, 

p. 810-825.

.1973, Use of relative age-dating methods in a stratigraphic

study of rock glacier deposits, Mt. Sopris, Colorado: Arctic and 

Alpine Research, v. 5, p. 401-416. 

___1974, Pedology, weathering, and geomorphological research:

New York, Oxford, 285 p.

Birkeland, P. W., Richmond, G. M., and Crandell, D. R., 1970, Status 

of correlation of Quaternary stratigraphic units in the western conterminous United States: Quaternary Research, v. 1, no. 2, 

p. 208-227.

Blackwelder, Eliot, 1915, Post-Cretaceous history of the mountains of 

central western Wyoming, Part 3: Journal of Geology, v. 23, 

p. 307-340.

Broecker, W. S., and van Donk, J., 1970, Insolation changes, ice 

volume, and the 180 record in deep sea cores: Reviews of Geophysics 

and Space Physics, v. 8, no. 1, p. 169-198.

Burke, R. M., 1979, Multiparameter relative dating (RD) techniques 

applied to morainal sequences along the eastern Sierra Nevada, 

California, and the Wallowa Lake area, Oregon: University of Colorado Ph. D. dissertation, 166 p.

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, p. 21-51.

Carrara, P. E., and Andrews, J. T., 1975, Holocene glacial/periglacial 

record, northern San Juan Mountains, southwestern Colorado: 

Zeitschrift fur Gletscherkunde and Glazialgeologie, Band XI, Heft 

2, p. 155-174.

Carroll, T., 1974, Relative age dating techniques and a late Quaternary chronology, Arikaree Cirque, Colorado: Geology, v. 2, no. 7, 

p. 321-325.

Carson, R. J., 1970, Quaternary geology of the south-central Olympic 

Peninsula, Washington: University of Washington Ph. D. dissertation, 67 p.

Cernohouz, J., and Sole, I., 1966, Use of sandstone wanes and 

weathered basalt crust in absolute chronology: Nature, v. 212, 

p. 806-807.

Christiansen, R. L., and Blank, R. H., Jr., 1972, Volcanic stratigraphy 

of the Quaternary Rhyolite Plateau in Yellowstone National Park: 

U.S. Geological Survey Professional Paper 729-B, 18 p.

Clark, M. M., 1967, Pleistocene glaciation of the drainage of the West 

Walker River, Sierra Nevada, Calif.: Stanford University Ph. D. 

dissertation, 170 p.

Colman, S. M., 1977, The development of weathering rinds on basalts 

and andesites and their use as a Quaternary dating method, 

western United States: University of Colorado Ph. D. dissertation, 

235 p.

Crandell, D. R., 1963, Surficial geology and geomorphology of the 

Lake Tapps quadrangle, Washington: U.S. Geological Survey Professional Paper 388-A, 84 p.

___1967, Glaciation at Wallowa Lake, Oregon, in Geological 

Survey research 1967: U.S. Geological Survey Professional Paper 

575-C, p. C145-C153.

___1972, Glaciation near Lassen Peak, northern California: U.S.

Geological Survey Professional Paper 800-C, p. C179-C188.

Crandell, D. R., and Miller, R. D., 1974, Quaternary stratigraphy and 

extent of glaciation in the Mt. Rainier region, Washington: U.S. 

Geological Survey Professional Paper 847, 59 p.

Curry, R. R., 1971, Glacial and Pleistocene history of the Mammoth 

Lakes area, California a geologic guidebook: Montana Department of Geology Geological Serial Publication 11, 49 p.
40 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Dreimanis, A., and Karrow, P. F., 1972, Glacial history in the Great

Lakes-St. Lawrence Region, the classification of the Wisconsin(an)

Stage, and its correlatives: International Geologic Congress, 24th

session, section 12, Quaternary Geology, Montreal, 1972, p. 5-15. 

Emiliani, C., 1955, Pleistocene temperatures: Journal of Geology,

v. 63, p. 538-578. 

___1966, Paleotemperature analysis of Caribbean cores P6304-8

and P6304-9 and a generalized temperature curve for the last

425,000 years: Journal of Geology, v. 74, p. 109-126. 

Emiliani, Cesar, and Shackleton, N. J., 1974, The Brunhes

epoch isotopic paleotemperatures and geochronology: Science, v.

183, p. 511-514. 

Engel, C. B., and Sharp, R. P., 1958, Chemical data on desert varnish:

Geological Society of America Bulletin, v. 69, p. 487-518. 

Fames, P. E., and Shafer, B. A., 1975, Summary of snow survey

measurements for Montana: U.S. Department of Agriculture, Soil

Conservation Service, 220 p. 

Fisher, R. A., 1954, Statistical methods for research workers: London,

Oliver and Boyd, 319 p. 

Fiske, R. S., Hopson, C. A., and Waters, A. C., 1963, Geology of

Mount Rainier National Park, Washington: U.S. Geological Survey

Professional Paper 444, 93 p. 

Foster, R. J., 1958, The Teanaway dike swarm of central Washington:

American Journal of Science, v. 256, no. 9, p. 644-653. 

Friedman, Irving, and Smith, R. L., 1960, A new dating method using

obsidian Part I, the development of the method: American Antiquity, v. 25, p. 476-522. 

Goldich, S. S., 1938, A study in rock weathering: Journal of Geology,

v. 46, no. 1, p. 17-58. 

Griffiths, J. C., 1962, Statistical methods in sedimentary petrology,

in Milner, H. B., ed., Sedimentary petrology, volume 1: London,

George Alien and Unwin, Ltd., p. 565-617. 

___1967, Scientific method in analysis of sediments: New York,

McGraw-HUl, 508 p.

Grim, R. E., 1968, Clay mineralogy: New York, McGraw-Hill, 596 p. 

Hamilton, L. J., and Paulson, Q. F., 1968, Geology and ground-water

resources of the Lower Bighorn Valley, Montana: U.S. Geological

Survey Water-Supply Paper 1876, 39 p. 

Hays, J. D., Imbrie, J., and Shackleton, N. J., 1976, Variations in the

earth's orbit pacemaker of the ice ages: Science, v. 194, no. 4270,

p. 1121-1132.

Hooke, R. LeB., Yang, H. Y., and Weiblen, P. W., 1969, Desert varnish, an electron probe study: Journal of Geology, v. 77, no. 3,

p. 275-288. 

Hunt, C. B., and Mabey, D. R., 1966, Stratigraphy and structure,

Death Valley, California: U.S. Geological Survey Professional

Paper 494-A, 162 p. 

Jackson, M. L., and Sherman, G. D., 1953, Chemical weathering of

minerals in soils: Advances in Agronomy, v. 5, p. 219-318. 

Jackson, T. A., and Keller, W. D., 1970, A comparative study of the

role of lichens and "inorganic" processes in chemical weathering of

recent Hawaiian lava flows: American Journal of Science, v. 269,

p. 446-466. 

Jenny, H., 1941, Factors of soil formation: New York, McGraw-Hill,

281 p. 

Kane, P. S., 1975, Glacial geology of Lassen Volcanic National Park,

California: Berkeley, University of California Ph. D. dissertation,

157 p. 

Kvenvolden, K. A., Blunt, D. J., and Clifton, H. E., 1977, Application

of amino acid stereo-chemistry to the correlation of late Pleistocene

deposits at Willapa Bay, Washington: Geological Society of

America Abstracts with Programs, v. 9, no. 7, p. 1062-1063. 

Loughnan, F. C., 1969, Chemical weathering of the silicate minerals:

New York, American Elsevier Publication Company, 154 p.

Ninkovich, D., Shackleton, N. J., Abdel-Monem, Obradovich, J; D., 

and Izett, G., 1978, K-Ar age of the late Pleistocene eruption of 

Toba, North Sumatra: Nature, v. 276, no. 5866, p. 574-577.

Oilier, C. D., 1969, Weathering: Edinburgh, Oliver and Boyd, 304 p.

Pierce, K. L., 1973, Surficial geologic map of the Mammoth 

quadrangle and part of the Gardiner quadrangle, Yellowstone National Park, Wyoming and Montana: U.S. Geological Survey 

Miscellaneous Geological Investigations Map 1-641.

___1979, History and dynamics of glaciation in the northern 

Yellowstone National Park area: U.S. Geological Survey Professional Paper 729-F, 90 p.

Pierce, K. L., Obradovich, J. D., and Friedman, I., 1976, Obsidian 

hydration dating and correlation of Bull Lake and Pinedale Glaciations near West Yellowstone, Montana: Geological Society of 

America Bulletin, v. 87, no. 5, p. 703-710.

Porter, S. C., 1964, Composite Pleistocene snow line of Olympic 

Mountains and Cascade Range, Washington: Geological Society of 

America Bulletin, v. 75, p. 477-482.

___1969, Pleistocene geology of the east-central Cascade Range, 

Washington: Guidebook for Third Pacific Coast Friends of the 

Pleistocene Field Conference, 54 p.

.1975, Weathering rinds as a relative-age criterion: Application

to subdivision of glacial deposits in the Cascade Range: Geology, 

v. 3, no. 3, p. 101-104.

_1976, Pleistocene glaciation of the southern part of the north

Cascade Range, Washington: Geological Society of America

Bulletin, v. 87, no. 1, p. 61-75. 

Porter, S. C., Stuiver, M., and Yang, I. C., 1977, Chronology of

Hawaiian glaciations: Science, v. 195, p. 61-63. 

Potter, R. M., and Rossman, G. R., 1977, Desert varnish: the importance of clay minerals: Science, v. 196, p. 1446-1448. 

Richmond, G. M., 1964, Glacial geology of the West Yellowstone

Basin and adjacent parts of Yellowstone National Park: U.S.

Geological Survey Professional Paper 435-T, p. 223-236. 

____1965, Glaciation of the Rocky Mountains, in Wright, H. E., Jr.,

and Frey, D. G., eds., The Quaternary of the United States:

Princeton University Press, p. 217-230. 

___1973a, Surficial geologic map of the Warm River Butte

quadrangle, Yellowstone National Park and adjoining area, Idaho 

and Wyoming: U.S. Geological Survey Miscellaneous Investigations Map 1-645.

_1973b, Surficial geologic map of the Grassy Lake Reservoir

quadrangle, Yellowstone National Park and adjoining area, Wyoming: U.S. Geological Survey Miscellaneous Investigations Map 

1-644.

.1976, Pleistocene stratigraphy and chronology in the mountains of western Wyoming, in Mahaney, W. C., ed., Quaternary 

stratigraphy of North America: Stroudsberg, Pa., Dowden, Hutchinson, and Ross, Inc., p. 353-379.

_1977, Extensive glaciers in Yellowstone National Park 114,000

and 88,000 years ago: Abstracts, X INQUA Congress, Birmingham, England.

Scheffe, H., 1959, The analysis of variance: New York, John Wiley, 

477 p.

Schmidt, D. L., and Mackin, J. H., 1970, Quaternary geology of Long 

and Bear Valleys, west-central Idaho: U.S. Geological Survey 

Bulletin 1311-A, 22 p.

Scott, W. E., 1977, Quaternary glaciation and volcanism, Metolius 

River area, Oregon: Geological Society of America Bulletin, v. 88, 

p. 113-124.

Shackleton, N. J., 1977a, Oxygen isotope stratigraphy of the Middle 

Pleistocene, in Shotten, F. W., ed., British Quaternary Studies, Recent Advances: Oxford, Clarendon Press, p. 1-16.

___1977b, The ocean oxygen isotope record stratigraphic tool
REFERENCES CITED 41

and paleoglacial record: Abstracts, X INQUA Congress, Birmingham, England, p. 415.

Shackleton, N. J., and Opdyke, N. D., 1973, Oxygen isotope and 

paleomagnetic stratigraphy of Equatorial Pacific core 

V28-238 oxygen isotope temperatures and ice volumes on a 105 

year and 106 year scale: Quaternary Research, v. 3, no. 1, p. 39-55.

Snedecor, G. W., 1956, Statistical methods: Iowa State University 

Press, 534 p.

Stuiver, Minze, Heuser, C. J., and Yang, I. C., 1978, North American 

glacial history extended.to 75,000 years ago: Science, v. 200, no. 

4337, p. 16-21.

Suggate, R. P., 1974, When did the last interglacial end?: Quaternary 

Research, v. 4, p. 246-252.

Thorn, C. E., 1975, Influence of late lying snow on rock-weathering 

rinds: Arctic and Alpine Research, v. 7, no. 4, p. 373-378.

Tukey, J. W., 1977, Exploratory data analysis: New York, AddisonWesley, 688 p.

U.S. Weather Bureau, 1959, Climatological data for the United 

States, by sections. Annual Summary: v. 46, 977 p.

Waldrop, H. A., 1975, Surficial geology of the West Yellowstone

quadrangle, Wyoming, Idaho, and Montana: U.S. Geological 

Survey Miscellaneous Geologic Investigations Map 1-648. 

Waldrop, H. A., and Pierce, K. L., 1975, Surficial geologic map of the 

Madison Junction quadrangle, Yellowstone National Park, Wyoming: U.S. Geological Survey Miscellaneous Geologic Investigations 

Map 1-651.

Willman, H. B., and Frye, J. C., 1970, Pleistocene stratigraphy of Illinois: Illinois State Geological Survey, Bulletin 94, 204 p.

Williams, H., 1932, Geology of Lassen Volcanic National Park, 

California: California University Department of Geological 

Sciences Bulletin, v. 21, no. 8, p. 195-385.

Wilson, J. A., and Carstens, M. O., 1975, Summary of snow survey 

measurements for Idaho: U.S. Department of Agriculture, Soil Conservation Service, 309 p.

Winkler, E. M., 1975, Stone Properties, durability in man's environment: Applied Mineralogy, v. 4, 230 p.

Yeend, W. E., 1969, Quaternary geology of the Grand and Battlement 

Mesas area, Colorado: U.S. Geological Survey Professional Paper 

617, 50 p.

APPENDIXES A-C
44 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

APPENDIX A. WEATHERING-RIND THICKNESS MEASUREMENTS

[a, fine-grained andesite; b, coarse-grained andesite; c, andesite, undivided; d, granular basalt; e, dense, glassy basalt; f, basalt, undivided; g, quartizite; h, other; N in measurement

columns, not measured or not given]

Measurements

Sample 

No.

Mean

Standard 

deviation

(mm)

Number Deposit

Rock 

type

West Yellows tone, Mont

C76-74

-74

-74

-75

C75-97

-98

-98

-99

-101

-94

-95

-96

-100

-102A

-102B

C78-125

-124

C75-106

C76 -51

-52

-69

C78-141

C76 -62

-63A

-63B

-64

C75-105

C76 -65

-68

C78-134

C75-107

C76 -66

-67

-59

-60

-61

-71

0.11

.10

.13

.10

.35

.44

.67

.67

.59

.25

.76

.78

.81

1.04

.93

.74

.60

.29

.20

.26

.29

.24

.27

.31

.45

.35

» 10jy

.39

.40

.35

.30

.40

.35

.97

.75

.53

.93

0.08

.06

.13

.07

.23

.22

.21

.24

.21

.14

.17

.21

.20

.18

.19

.13

.20

.14

.08

.16

.14

.12

.19

.16

.21

.16

.17

.18

.16

.16

.15

.11

.13

.32

.24

.23

.30

34

31

32

21

39

41

25

11

15

35

56

51

55

34

30

36

39

40

63

22

39

39

33

25

28

39

50

33

34

38

31

36

35

38

40

47

56

Deckard Flats

 do 

 do 

 do 

Pinedale 

 do 

 do 

 do 

 do 

Bull Lake 

 do 

 do 

 do 

 do 

 do 

Me Call,

Pinedale 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

j

 do 

 do 

 do 

 do 

 do 

 do 

Intermediate

 do 

 do 

 do 

d

f

h

f

d

d

d

f

f

d

d

d

d

d

d

Idaho

e

e

e

e

e

e

e

e

e

e

e

e 

e

e

e

e

e

e

e

e

e

e

Remarks

., Wyo.

Pinedale recessional deposits.

Gallatin intrusives.

Pinedale terminal deposits.

Surface stones.

Do.

Varying rock types, poor site.

Eroding site.

Wetter site.

Do.

Side-valley recessional moraine.

Do.

Inner moraine .

Do.

Do.

Do.

Outwash from inner moraine.

Intermediate moraine.

Do.

Intermediate moraine, angular stones.

Intermediate moraine.

Outer moraine.

Do.

Do.

Do.

Outwash.

Do.

Do.

Innermost moraine.

Do.

Innermost moraine, stones from

loess above till.

Innermost moraine.
APPENDIX A 45

Measurements (mm)

Sample 

No.

Mean

Standard 

deviation Number Deposit

Rock Remarks 

type

McCall, Idaho Continued

C78-121

-135

-137 

-136

1 -10 8B 

1 -104A 

1 C76 -54B

1 -54B

-54A 

1 -57 

1 -58

2C75-109

2C76 -55

2 -56 

^75-1048 

1 C76 -54C

1 -54C

.84

.84

.71 

.59

1.41 

1.71 

1.23 

1.85

2.13

.02 

1.35 

1.52

1.96

1.44

1.69 

1.18 

1.42

1.50

.19

.16

.15 

.22

.28 

.32 

.45 

.61

.65

.05 

.33 

.29

.40

.30

.47 

.35 

.29

.26

39

32

33 

36

44 

30 

43 

32

32

24 

36 

38

36

31

32 

38 

40

40

 do 

 do 

 do 

 do 

Bull Lake 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

Not known 

 do 

__ A n _______

e

e

e 

e

e 

e 

e 

e

e

e 

e 

e

e

e

e 

e 

e

e

Yakima Valley,

C75-131 

-130 

-130 

-133

C76 -43

-42

-44

-45

-46

-47

C75-134

-135 

-140 

None

0.25 

.52 

.43 

.71

.78

.71

.65

.68

.30

.40

1.05

1.10 

1.96 

2.78

0.04 

.06 

.21 

.12

.19

.16

.15

.22

.14

.18

.17

.11 

.24 

.23

225 

193 

31 

279

31

30

34

41

36

38

287

413 

346 

70

Domerie 

Ronald 

 do 

Bullfrog 

 do 

 do 

 do 

 do 

 do 

 do 

Indian JohnSwauk Prairie

Pre-Thorp(?)-

e

e 

e

e

e

e

e

e

e

e

e

e

e 

e

Mount Rainier,

C75-123

-123

-124

-116

-116

0.23

.27

.16

.13

.08

0.16

.17

.11

.09

.06

34

28

38

27

27

Vashon 

 do 

 do 

Evans Creek-

 do 

a

b

a

a

b

Do.

Do.

Do.

Innermost moraine, eroding site, 

reworked stones.

Inner moraine, no loess. 

Inner moraine, beneath 2 m loess. 

Intermediate moraine. 

Intermediate moraine, SMC 3 measurements.

Intermediate moraine, KLP 3 measurements.

Intermediate moraine, unoxidized till. 

Intermediate moraine. 

Do.

Outer moraine .

Do.

Do. 

C horizon of soil buried by Bull Lake Till. 

B horizon of soil buried by Bull Lake Till, 

SMC3 measurements. 

Soil buried by Bull Lake Till, B horizon, 

KLP3 measurements.

Wash.

Data from Porter (1975). 

Do. 

This study. 

Data from Porter (1975).

End moraine, this study.

Outwash terrace.

Do.

Do.

Outwash terrace, variable lithologies,

thick loeas cover.

Outwash terrace .

Data from Porter (1975).

Do. 

Do. 

Do.

Wash.
46 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Measurements (mm)

Sample 

No.

Mean

Standard 

deviation Number Deposit

Rock Remarks 

type

Mount Rainer, Wash,

-119

-119

-129

-129

C76 -41

-41

C78-118

C77 -44

C75-120

-120

-122

-122

-128

1 C76-40

-40

C78-115

-115

1 11fi llo 

-116

1 -116

-117

-117

2 -119

2C75-121

2 -121

2 -126

2 -125

2 -118

2 -118

.15

.17

.14

.12

.21

.24

.17

1.03

.63

.84

.53

.65

1.05

1.45

1.95

.78

.82

1.03 

.99

1.29

.34

.31

2.09

3.99

3.50

2.69

4.66

7.38

8.63

.12

.11

.08

.09

.15

.24

.12

.18

.25

.33

.29

.29

.39

.56

.54

.20

.21

.31

.24

.30

.29

.28

.68

.71

.69

.71

1.19

1.43

1.88

11

32

24

38

18

26

22

21

16

28

33

35

36

41

38

38

31

34

26

43

43

19

33

36

39

44

35

21

15

 do 

 do 

 do 

 do 

 do 

 do 

 do 

Ha yd en Creek

___H n __

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

____ A ~_ _____

 do 

 do 

 do 

 _ _ J ,%__. _ .. _

Ha yd en Creek(?)

Wingate Hill

 do 

 do 

Logan Hill 

 do 

 do 

a

b

a

b

a

b

a

a

a

b

a

b

a

a

b

a

b

b

a

a

b

a

a

b

a

a

a

b

Puget Lowland,

C76 -29

-30

C78-110

C76 -22

-24

-28

-32

-39

-38

1 -26

1 -27

-33

0.86

.90

.68

.26

.21

.16

.24

.25

.71

1.13

.87

.34

0.53

.53

.28

.17

.14

.09

.14

.19

.30

.38

.35

.22

27

13

32

31

37

44

31

45

40

56

68

55

Not known 

 do 

 do 

Vashon 

 do 

Lower Fraser

terrace.

 d o 

 do 

High Fraser

terrace.

Salmon Springs

 do 

Middle Salmon

f

f

f

f

f

f

f

f

f

f

f

f

. Cont inued

Out wash.

Slightly eroding site.

Do.

Deposit buried by about 1 m of loess*

Do.

Slightly eroding site, may be mixed

with older till.

Inner moraine.

Do.

Outwash, stones from within loess.

Do.

Stones from within thin loess.

Do.

Stones from within till beneath thin loess.

Recessional outwash.

Do.

Oldest of three Hayden Creek(?) terraces

downstream from terminus.

Wash.

First marine terrace(?), Grays Harbor.

Do.

Do.

Replicate of C76-32.

Buried beneath 5 m of loess.

Springs 

terrace,
APPENDIX A 47

Measurements

Sample 

No.

Mean

(mm)

Rock Remarks 

Standard type 

deviation Number Deposit

Puget Lowland, Wash. Continued

-37A 

1 -37B

None 

DoDo 

C75 -84 

-84

-92

-92

C76 -07 

-07

-12

-12

-06 

-06

C75 -89 

-89

C76 -08

-08

-13

-13

-11 

-11 

-11 

-11

C75 -87 

-87

-88

-88

-85

-85

C76 -10

-10

-09 

-09 

-14

-14

-14

-14 

1 C75 -86 

1 -86

1 -90 

1 -90

.57 

1.07

3.3

2.6 

6

0.19 

.20

.15

.11

.17 

.14

.18

.17

.52 

.57

.40 

.48

.24

.27

.42

.39

.30 

.29 

.35 

.31

.61 

.81

.84

1.01

.57

.62

.70

.61

.77 

.71 

.74

.86

.84

.84 

.96 

1.45

1.37 

2.23

.48 

.53

2.0

2.5 

3

0.10 

.18

.10

.11

.10 

.10

.07

.08

.35 

.38

.16 

.21

.11

.12

.22

.22

.15 

.14 

.18 

.18

.22 

.21

.27

.36

.20

.26

.24

.29

.24 

.27 

.23

.20

.27

.22 

.27 

.49

.48 

.92

37 

38

N

N 

N

15 

50

23

46

23 

22

17

38

10 

21

35 

32

38

34

23

60

27 

27 

33 

33

32 

33

44

31

43

26

39

7

45 

11 

17

17

77

77 

32 

31

26 

31

 do 

 do 

Helm Creek 

 do 

Wedekind Creek

Lassen Peak

Tioga 

 do 

 do 

 do 

 -do- 

 do 

 do 

"early Tioga" 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

 do 

__ tt n _______

Tahoe 

 do 

 do 

 do 

__ do _____

 do 

 do 

___H n . 

_ _ .,{ n, __ . ____

 do 

 do 

pre-Tahoe 

I~do-------

f 

f

f

f 

f

>

a 

b

a

b

a 

b

a

b

a 

b

a 

b

a

b

a

b

a 

a 

b 

b

a 

b

a

b

a

b

a

b

a 

b 

a

a

b

b 

a 

b

a 

b

Buried beneath 3 m of loess.

Data from Carson (1970).

Data from Carson (1970); outwash. 

Data from Carson (1970).

Calif.

Probably thin, older deposit. 

Do.

SMC3 measurements, replicate of C75-89. 

KLP 3 measurements, replicate of C75-89. 

SMC measurements, replicate of C75-89. 

KLP measurements, replicate of C75-89.

SMC measurements.

KLP measurements.

SMC measurements.

KLP measurements .
48 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Measurements

Sample 

No.

Mean

Standard 

deviation

(mm)

Number Deposit

Rock Remarks 

type

Lassen Peak, Calif. Continued

1 -91

1 -91

.91

1.53

.23

.46

31

27

 do 

 do 

a

b

Truckee River, Calif., Nev.

C75 -75

-75

-81

-81

-76

-76

-80

-80

-83

-83

C76 -04

-04

1 C75 -79

1 -79

1 -78

1 -78

1 00

 oZ 

1 oZQ O

1 -77

1 -77

C76 -05

-05

C75 -62

-58

-60

-59

-61

0.15

.16

.16

.16

.24

.35

.19

.20

.22

.16

1 Q lo

.18

1.06

1.16

.89

.89

Of) . oU

Q C

. o J

.75

1.00

.36

.60

0

.26

.32

.28

.46

0.06

.07

.08

.08

.11

.23

.09

.13

.10

.09

. no. Uo

.09

.29

.31

.22

.22

.17

 Z.Z. 99

.30

.16

.33

Bighorn

N

0.26

.31

.29

.33

17

40

21

40

t Q 30

36

43

37

32

40

/ O 42

25

41

37

32

27

33

39

31

39

23

33

River ,

N

33

32

35

30

Tioga 

 do 

 do 

 do 

Ta V. n <=>_____

 do 

 do 

 do 

 do 

 do 

 do 

 do 

Donner Lake-

 do 

 do 

 do 

 do 

 do 

Hob art 

 do 

Not known 

 do 

Mont. (Mapping

First terrace

Second terrace

Third terrace

Fourth terrace

Fifth terrace

Mammoth, Calif, (mapping of

C75 -72

-72

-63

-63

-63

-73

-73

-65

-65

0.23

.21

.25

.22

.17

.18

.26

.50

.50

0.17

.10

.11

.12

.08

.11

.17

.29

.39

42

21

20

17

7

25

15

32

26

Tioga 

 do 

 r? n __ 

 do 

 do 

Tahoe 

 do 

Casa Diablo-

 do 

a

b

a

b

b

a

b

a

b

b

a

b

a

b

b

b

a

b

Out wash .

Do.

Outwash .

Do.

Do.

Do.

Outwash.

Do.

Do.

Do.

Buried.

Do.

Buried beneath Donner Lake Till.

Do.

of Hamilton and Paulson (1968))

h

h

h

h

h

Curry

f

g

g

h

f

g

f

g

f

Miscellaneous metavolcanics .

Do.

Do.

Do.

Do.

(1971) and Burke (1979))

Inner moraine.

Do.

Outer moraine.

Outer moraine, quartz latite.

Outer moraine.
APPENDIX A 49

Measurements (mm)

Sample 

No.

Mean

Rock Remarks 

Standard type 

deviation Number Deposit

West Walker River, Calif, (mapping of Clark (1967))

C75 -69 

-68 

-70 

-67

-66 

-66 

-71 

-71

C75-115 

-113 

-114 

-112

C76 -01 

-03 

1 -02

0.18 

.26 

.25 

.40

.43 

.37 

.38 

1.72

0.26 

.38 

.63 

.94

0.08 

.95 

1.39

0.15 

.31 

.23 

.27

.27 

.22 

.34 

.92

0.19 

.33 

.37 

.36

0.06 

.23 

.37

34 

40 

41 

36

36 

30 

25 

15

Wallowa

29 

33 

43 

38

Grand

39 

42 

56

Tioga c

JLdllUL \~

 do c 

Deep Creek c

Grouse Meadows c

 do g 

Huntoon Gravel c 

 do f

Lake, Ore. (mapping of Crandell (1967) )

Wt1* _______ f

Tto f 

Jt f 

Cto f

Mesa, Colo. (mapping of Yeend (1969))

Late Pinedale f Grand Mesa Formation. 

Pinedale f Do. 

Bull Lake f Land's End Formation.

Siletz River, Ore.

C76 -18 

-19 

-21 

-21

1.87 

.44 

.27 

2.38

0.78 

.14 

.09 

.80

27 

40 

26 

14

Not known e Buried gravel below second(?) terrace. 

 do e 15-m (first?) terrace. 

 do e Do. 

 do f 15-m (first?) terrace, diffuse inner rinds

Spokane, Wash.

C76 -50 

-50

0.06 

.07

0.06 

.06

27 

21

Not known e Gravel from last Missoula flood. 

 do d Do.

South Fork Shoshone River, Wyo.

C76 -76 

-76

0.08 

.08

0.07 

.08

24 

20

Warm River Butte

C 78-100 

-101 

-102 

-108

0.32 

.29 

.29 

.24

0.13 

.13 

.12 

.10

36 

31 

36 

34

Pinedale(?)- a 

 do b

Area, Idaho, Wyo. (mapping of Richmond (1973a, b) )

Middle Pinedale f 

 do f 

Early Pinedale f 

 do f

-109 .32 .11 30 do 
50 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Sample 

No.

Measurements (mm)

Standard 

Mean deviation Number Deposit

Rock 

type

Remarks

Warm River Butte Area, Idaho, Wyo. (mapping of Richmond (1973a, b)) Continued

1

1

1

-103

-106

-107

-98

-99

-104

- 97

-105

.26

.34

.32

1.04

.99

.76

.14

.53

.10

.13

.13

.20

.16

.16

.19

.21

33

42

25

32

34

37

27

25

Bull Lake 

 do 

 do 

Sacagawea Ridge

 do 

j ^

 do 

 do 

f

f

f

f

f

f

f In calcareous soil, buried by 3 m of loess

f Buried by 2. 5 m of loess .

1 0uter part of weathering rind is soft.

2 0uter part of weathering rind is very soft.

3 SMC, S. M. Colman; KLP, K. L. Pierce.

^W, T, J, C, arbitrary letter designations of units from Crandell (1967); t, till; o outwash.

APPENDIX B. SAMPLE LOCATIONS AND SITE DATA

[Climatic data for principal sampling areas given in headings in the form (Station, MAP, MAT), where MAP is mean annual precipitation (cm) and MAT is mean annual temperature 

(°C); N/A, not applicable. Data from U.S. Weather Bureau (1959). Where all topographic maps are in the same State as sampling area. State name not given]

Site No. Location Topographic map Vegetation Altitude 

(m)

Soil 

PH 1

West Yellowstone, Mont., Wyo. (West Yellowstone, 53.7, 1.7)

C76- 74 

- 75 

C75- 97

- 98 

- 99

-101 

- 94

- 95 

- 96 

-100 

-102

Junction, Grand Loop and Bunsen Peak Roads 

0.3 km SW. of Cougar Creek Patrol Cabin 

0.7 km NNE. of Madison Range Overlook 

NW1/4SW1/4NW1/4, sec. 25, T. 12 S., R. 4 E.

NW1/4NW1/4NW1/4, sec. 15, T. 12 S., R. 4 E. 

NW1/4SW1/4SW1/4, sec. 15, T. 12 S. , R. 5 E. 

SW1/4SE1/4SE1/4, sec. 10, T. 12 S., R. 5 E. 

NE1/4SE1/4NE1/4, sec. 6, T. 14 S., R. 5 E.

 do 

Madison Junction 

15', Wyo.

 d o 

*

Tepee Creek 15', 

Mont. 

 do 

 d o 

West Yellowstone 

15', Wyo.

Pine 

Grass, sagePine, grass-

 do 

 do 

 do 

Grass, sage-

 do 

 do 

Grass, fir 

Pine, grass2,245 

2,115 

2,110

2,100 

2,080

2,065 

2,015

2,015 

2,020 

2,090 

2,050

5.0

5.8

5.6 

5.7

McCall, Idaho (McCall, 69.4, 4.4)

f "7 Q 1 9 £

C78-124

C75-106

C76- 51

- 52

- 69

C78-141

nf\ f\")

C*GtlLGlT SGC -*-^ >

SW1/4SW1/4NW1/4,

NW1/4SW1/4NW1/4,

NE1/4NE1/4SE1/4,

NW1/4NW1/4NE1/4,

SW1/4NW1/4SE1/4,

NUl /AQF1 /AQU1 /A

r. 15

sec.

sec .

sec.

sec.

sec.

N.,

7,

3,

n

3,

3,

3,

0

T.

T.

T. 

T.

T.

T.

T.

2

17

15 N.,

1 Q vr

18 N.,

18 N.,

18 N.,

IS N.

R.

R.

R.

R.

R.

3 E.

O T-l

J EJ 

3 E.

3 E.

3 E.

1 T7.

U3SC3Q6 J.3

 d 0 - - 

McCall 7 1/2' 

 d o 

 do 

 do 

 do 

j

Fir, grass 

Pine ~

Pine-fir 

 do 

 do 

 do 

 An 

2,050

1,970

1,540

1,545 

1,540

1,540

1,530

i . sin

5.7

__

__
APPENDIX B 51

Site No. Location Topographic map Vegetation Altitude 

(m)

Soil 

PH 1

McCall, Idaho (McCall, 69.4, 4. 4) Continued

- 63 

- 64 

C75-105 

C76 -65 

-68

C78-134 

C 75-10 7 

C76- 66 

- 67

- 59 

- 60 

- 61 

- 71

C78-121 

-135

-137 

-136

C75-108 

-104 

C76- 54 

- 57 

- 58

C76-109 

- 55 

- 56

C75-131 

-130 

-133 

C76- 42

- 43 

_ 44

- 45 

- 46

- 47 

C75-134 

-135

Mount

C75-123 

-124 

-116 

-119

-129 

C76- 41 

- 40 

C78-118

C77- 44 

C75-120 

-122 

-128

NE1/4SE1/4SE1/4, sec. 8, T. 18 N. , 

NW1/4SW1/4SE1/4, sec. 8, T. 18 N., 

SW1/4NE1/4NW1/4, sec. 16, T. 18 N. , 

SW1/4NW1/4NW1/4, sec. 16, T. 18 N., 

NW1/4NE1/4NE1/4, sec. 16, T. 18 N. ,

NE1/4NE1/4SW1/4, sec. 7, T. 18 N., 

SE1/4NW1/4SE1/4, sec. 16, T. 18 N. , 

SW1/4NW1/4SW1/4, sec. 16, T. 18 N., 

SE1/4SE1/4NE1/4, sec. 16, T. 18 N. ,

NE1/4SW1/4NW1/4, sec. 15, T. 18 N., 

SW1/4NE1/4NW1/4, sec. 15, T. 18 N. , 

SW1/4NE1/4NW1/4, sec. 15, T. 18 N., 

SE1/4NE1/4NW1/4, sec. 15, T. 18 N. ,

SW1/4NE1/4SW1/4, sec. 7, T. 18 N., 

NW1/4NE1/4SW1/4, sec. 7, T. 18 N.,

NE1/4NW1/4NW1/4, sec. 15, T. 18 N., 

SE1/4NW1/4NE1/4, sec. 16, T. 18 N. ,

NW1/4NW1/4SW1/4, sec. 15, T. 18 N., 

NW1/4SE1/4SW1/4, sec. 22, T. 18 N. , 

NW1/4SE1/4SW1/4, sec. 22, T. 18 N., 

SW1/4SE1/4NW1/4, sec. 22, T. 18 N. , 

NW1/4NW1/4NE1/4, sec. 22, T. 18 N.,

SW1/4SE1/4NE1/4, sec. 33, T. 18 N. , 

NW1/4NE1/4SE1/4, sec. 33, T. 18 N., 

NW1/4SW1/4NW1/4, sec. 34, T. 18 N. ,

Yakima Valley, Wash.

SW1/4NW1/4SE1/4, sec. 2, T. 20 N. , 

SW1/4NW1/4SW1/4, sec. 18, T. 20 N., 

NW1/4NW1/4SE1/4, sec. 29, T. 20 N., 

 do 

SW1/4NE1/4SW1/4, sec. 19, T. 20 N. , 

SE1/4SE1/4NE1/4, sec. 34, T. 20 N., 

NE1/4SW1/4SE1/4, sec. 33, T. 20 N., 

NW1/4NE1/4NE1/4, sec. 14, T. 18 N.,

NE1/4SW1/4SW1/4, sec. 35, T. 18 N., 

SE1/4SW1/4SE1/4, sec. 1, T. 19 N., 

SW1/4SW1/4NW1/4, sec. 29, T. 20 N. ,

Rainier, Wash. (Puyallup, 103, 10.

NE1/4NW1/4NW1/4, sec. 8, T. 17 N. , 

NE1/4NE1/4NE1/4, sec. 16, T. 20 N., 

NE1/4NW1/4NE1/4, sec. 28, T. 12 N. , 

NW1/4SE1/4NE1/4, sec. 28, T. 15 N.,

NW1/4SE1/4SE1/4, sec. 11, T. 16 N., 

SW1/4NE1/4NE1/4, sec. 31, T. 16 N. , 

NE1/4NW1/4NE1/4, sec. 23, T. 12 N.,

SE1/4NE1/4NW1/4, sec. 9, T. 12 N., 

SE1/4SW1/4NW1/4, sec. 11, T. 15 N., 

NE1/4SE1/4NW1/4, sec. 9, T. 14 N. , 

NF.1 /4NF.1 /4NF.1 Ik. sor. S T. 1Q N..

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E. 

R. 3 E.

R. 3 E. 

R. 3 E. 

R. 3 E.

(Cle Elum

R. 14 E. 

R. 15 E. 

R. 15 E.

R. 15 E. 

R. 15 E. 

R. 16 E. 

R. 17 E.

R. 18 E. 

R. 15 E. 

R. 17 E.

5; Buckley

R. 4 E. 

R. 6 E. 

R. 6 E. 

R. 6 E.

R. 6 E. 

R. 6 E. 

R. 1 E.

R. 2 E. 

R. 4 E. 

R. 5 E.

R. 8 K..

 do 

 do 

 do 

 do 

 do 

Meadows 7 1/2' 

MnPall 7 1/9' _

___ A n _____ . ___________

 do 

___ J n ___ _____________

___ J n __________ ______

___J .-, __ .___ __ .____ _ .__

 do 

 d o 

McCall 7 1/2' 

__ J^.., ___ _ ___,__,__ ._,____

 do 

 do 

 do 

 do 

 do 

Lake Fork 7 1/2' 

 do 

 do 

Fir, pine 

Pine-fir 

Pine 

 do 

 do 

Grass, sage- 

 do 

 do 

Pine, aspen- 

 do 

_ /<-. «__..»_____

 do -

Grass, sage, 

pine. 

Grass, pine, 

fir.

T>4 no 

Pine, fir 

Grass, aspen 

Pine 

 do 

Pine-fir 

 do 

 do 

 do 

1,535 

1,540 

1,540 

1,545 

1,555

1,550 

1,535 

1,525 

1,540

1,560 

1,560 

1,560 

1,560

1,550 

1,550

1,570 

1,555

1,550 

1,585 

1,585 

1,585 

1,585

1,550 

1,550 

1,555

6.1

5.5

6.0 

5.9

5.6

, 56.0, 7.9; Ellensburg, 23.0, 8.3)

Cle Elum 15' 

 d o 

Cle Elum 15' 

_j ___, _ . _ 

Thorp 15' 

 A <-<__. _ . 

Cle Elum 15' -

, 126, N/A; Longmire,

Chop Valley 15' 

Mineral 15' 

Ohop Valley 15' 

Mineral 15' 

Pine, grass- 

 do 

 do 

 do 

Pine, fir 

Pine, grassPine-grass 

Grass-sage 

Grass-sage?-

 do 

209, N/A; Stampede

Mixed forest

T7-i *-

Mixed forest 

 do 

 do 

 do 

 do 

 do 

 do 

 Hr, 

690 

675 

655 

655

695 

625 

570 

505

470 

645 

750

Pass ,

200 

200 

280 

515

905 

590 

610 

110

165 

380 

445

AfiS

5.8 

6.0 

6.0

6.2 

6.3

234, 4.2)

5.2

5.8 

5.8

5.4
52 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Site No.

Mount

C78-115 

-116 

-117 

-119

C75-121 

-126 

-125 

-118

Location

Rainer, Wash. (Puyallup, 103,

NE1/4SW1/4SE1/4, sec. 10, 

NW1/4NW1/4NW1/4, sec. 15, 

NW1/4NE1/4NE1/4, sec. 2, 

NE1/4SW1/4NE1/4, sec. 21,

Center sec. 2, T. 15 N. , 

NW1/4SE1/4NW1/4, sec. 35, 

NW1/4SW1/4NE1/4, sec. 35, 

Center border sec. 26-35,

T. 

T. 

T. 

T.

R. 

T. 

T. 

T.

10.5; Buckley,

12 N., 

12 N., 

11 N. , 

12 N.,

4 E. 

20 N., 

20 N., 

13 N.,

Puget Lowland, Wash.

C76- 29

- 30 

C78-110 

C76- 22 

- 24

- 28 

- 32 

- 39 

- 38

- 26 

- 27 

- 33 

- 37

C75- 84 

- 92 

C76- 07 

- 12 

- 06

C75- 89 

C76- 08 

- 13 

- 11

C75- 87 

- 88 

- 85 

C76- 10 

- 09 

- 14

C75- 86 

- 90 

- 91

NE1/4SE1/4NE1/4

SW1/4NE1/4NE1/4 

NW1/4NE1/4SW1/4 

SW1/4NW1/4NW1/4 

NW1/4SE1/4NE1/4

SE1/4SW1/4SE1/4 

NE1/4NW1/4NE1/4 

 do 

NE1/4SE1/4NW1/4

NE1/4NE1/4SE1/4 

SW1/4SW1/4SW1/4 

SE1/4NW1/4SE1/4 

NW1/4NW1/4SW1/4

SW1/4NW1/4NW1/4 

NW1/4SE1/4NE1/4 

SW1/4SE1/4SE1/4 

SE1/4SW1/4SW1/4 

NE1/4NE1/4NW1/4

NW1/4SE1/4SE1/4 

SE1/4SE1/4NE1/4 

NW1/4SW1/4SE1/4 

NW1/4SE1/4SE1/4

SW1/4NE1/4NE1/4 

SW1/4SW1/4SW1/4 

SW1/4SW1/4NE1/4 

SW1/4SE1/4SW1/4 

NE1/4SE1/4NE1/4 

NW1/4NE1/4NE1/4

SE1/4SW1/4NE1/4 

NE1/4NW1/4NE1/4 

SW1/4SW1/4SE1/4

, sec.

, sec. 

, sec. 

, sec. 

, sec.

, sec. 

, sec.

, sec.

, sec. 

, sec. 

, sec. 

, sec.

Lassen

, sec. 

, sec. 

, sec. 

, sec. 

, sec.

, sec. 

, sec. 

, sec. 

, sec.

, sec. 

, sec. 

, sec. 

, sec. 

, sec. 

, sec.

, sec. 

, sec. 

, sec.

27,

29, 

14, 

11, 

8,

18,

2,

33,

6, 

3, 

25, 

28,

T.

T. 

T. 

T. 

T.

T. 

T.

T.

T. 

T. 

T. 

T.

Peak,

34, 

10, 

4, 

35, 

4,

22, 

21, 

35, 

22,

28, 

22, 

20, 

27, 

34, 

3,

20, 

28, 

16,

T. 

T. 

T. 

T. 

T.

T. 

T. 

T. 

T.

T. 

T. 

T. 

T. 

T. 

T.

T. 

T. 

T.

Truckee River

C75- 75

- 81 

- 76 

- 80 

- 83

r 7A_ n/,

SW1/4SW1/4NW1/4

NE1/4SE1/4NW1/4 

NE1/4NW1/4SW1/4 

NW1/4NW1/4SW1/4 

NE1/4SE1/4SE1/4

CUT //.CF1 //,WU1 //.

, sec.

, sec. 

, sec. 

, sec. 

, sec.

16,

16, 

16, 

5, 

7,

o

T.

T. 

T. 

T. 

T.

T19 N.,

20 N., 

19 N., 

20 N., 

20 N.,

19 N., 

17 N.,

18 N.,

19 N., 

19 N., 

18 N., 

18 N.,

Calif.

30 N., 

31 N., 

29 N., 

31 N., 

29 N.,

29 N.,

29 N., 

31 N., 

29 N.,

29 N., 

29 N., 

29 N., 

29 N., 

29 N., 

30 N.,

29 N., 

29 N., 

29 N.,

, Calif

17 N.,

17 N., 

17 N., 

17 N., 

19 N.,

17 W_

R. 

R. 

R. 

R.

R. 

R. 

R.

2 E. 

3 E. 

5 E. 

1 E.

7 E. 

7 E. 

1 E.

Topographic map Vegetation

126, N/A; Longmire, 209, N/A; Stampede

,

. Spirit Lake 15' 

Chop Valley 15' 

_j_.___________ __

 do 

 do 

 do 

 do 

 do 

 do 

 do 

Altitude 

(m)

Pass, 234,

165 

270 

260 

135

425 

475 

490 

200

Soil 

PH 1

, 4.) Cont.

5.6

5.5

(Oakville, 139, 10.5; Blue Glacier, 397, 1.6)

R.

R. 

R. 

R. 

R.

R. 

R.

R.

R. 

R.

R. 

R.

12 W.

12 W. 

12 W. 

6 W. 

5 W.

6 W. 

7 W.

8 W.

6 W. 

6 W. 

7 W. 

8 W.

(Mineral

R. 

R. 

R. 

R. 

R.

R. 

R. 

R. 

R.

R. 

R. 

R. 

R. 

R. 

R.

R. 

R. 

R.

. ,

R.

R. 

R. 

R. 

R.

T>

4 E. 

4 E. 

6 E. 

3 E. 

6 E.

4 E. 

6 E. 

3 E. 

4 E.

4 E. 

4 E. 

4 E. 

6 E. 

6 E. 

3 E.

6 E. 

6 E. 

6 E.

Nev.

16 E.

16 E. 

16 E. 

17 E. 

18 E.

1 A P.

Copalis Beach 

7 1/2'. 

Moclips 7 1/2' 

Elma 15' 

 d o 

 do 

Wynoochee 

Valley 15'.

Elma 15' 

___ A n_____ __ _ 

Wynoochee 

Valley 15'.

, 131, 8.0; Manzanita

Lassen Peak 15' 

Manzanita Lake 15'- 

Mt. Harkness 15' 

Mt. Harkness 15' 

Lassen Peak 15' 

 do 

 do 

 do 

 d o 

Mt . Harkness 15' 

Lassen Peak 15' 

 d o 

 do 

 d o 

Mixed forest

 do 

 do 

Fir 

Mixed forest

Mixed forest

 do 

V-t » 

Mixed forest 

 do 

 do 

Lake, 108, 6.5)

Pine, grassPine 

Pine, grassFir 

Pine 

 do 

 do 

Fir 

Pine 

 do 

 do 

_ rln 

Pine, fir 

Pine 

Fir, pine 

P4 n o_ 

 do 

 do 

20

25 

20 

140 

150

65 

10 

10 

25

105 

130 

35

50

1,995 

1,790 

1,560 

1,855 

1,560

1,525 

1,540 

1,900 

1,525

1,625 

1,575 

1,605 

1,485 

1,480 

715

1,625 

1,660 

1,705

5.1 

5.2

5.9

5.9

5.9

6.1 

5.3

(Truckee, 80.0, 6.0; Reno, 18.0, 9.5)

Truckee 15', 

Calif. 

 d o 

 d o 

Verdi 7 1/2', Nev.-

ITVii/'1/-oo T^' PalHf.

Pine 

 do 

 do 

Sage, grassGrass, pine1,800

1,795 

1,825 

1,775 

1,485

i onn

6.1 

5.8

6.2
APPENDIX B 53

Site No. Location

Truckee River, Calif.,

C75- 79 

- 78 

- 82

- 77 

C76- 05

C75- 62 

- 58 

- 60

- 59 

- 61

SE1/4NW1/4SW1/4, 

SE1/4SE1/4S El/4, 

NE1/4SW1/4SE1/4,

SW1/4SW1/4SE1/4, 

SE1/4NW1/4SW1/4,

NE1/4SE1/4SE1/4, 

NE1/4SE1/4SW1/4, 

SW1/4SE1/4S El/4,

SW1/4SE1/4SW1/4, 

NE1/4SE1/4SE1/4,

sec 

sec 

sec

sec 

sec

sec 

sec 

sec

sec 

sec

. 11, 

. 25, 

. 18,

. 10, 

. 11,

. 33, 

 1, 

 19,

. 19, 

 2,

T. 

T. 

T.

T. 

T.

T. 

T. 

T.

T. 

T.

17 

18 

19

17 

17

5 

6 

4

4 

4

Nev.

N., 

N., 

N.,

N., 

N.,

s.,

S., 

S.,

s., 

s.,

R. 

R. 

R.

R. 

R.

R. 

R. 

R.

R. 

R.

Topographic map

(Truckee

16 E. 

16 E. 

18 E.

16 E. 

16 E.

Bighorn

31 E. 

31 E. 

31 E.

31 E. 

31 E.

Vegetation Altitude Soil 

(m) pH 1

, 80.0, 6.0; Reno, 18.0, 9.5) Continued

_ j _________________

 d o 

Verdi 7 1/2', Nev.- 

Truckee 15', Calif.

_/4,-» 

River, Mont.

Yellowtail 

Dam 7 1/2'. 

Mountain Pocket 

Creek 7 1/2'. 

Lemonade 

Springs 7 1/2'.

Woody Creek 

Camp 7 1/2'.

 do 

Sage, grassPine 

 do 

Grass, sage-

 do 

Sage, grass1,785 6.4 

1,755 

1,510 6.2

1,800 6.0 

1,785

970 

990 

1,005

1,025 

1,085

Mammoth, Calif.

C75- 72

- 63 

- 73 

- 65

SW1/4SE1/4NE1/4,

SE1/4SE1/4S El/4, 

SE1/4SE1/4SE1/4, 

SE1/4NE1/4SW1/4,

sec

sec 

sec 

sec

 2,

 2, 

. 36, 

. 31,

T.

T. 

T. 

T.

4

4 

3 

3

s.,

s., 

s., 

s.,

R.

R. 

R. 

R.

27 E.

27 E. 

27 E. 

28 E.

Mt. Morrison 15' 

 d 0 

 d o 

Sage, manzanita. 

 do 

Sage, grass- 

 do 

2,390

2,450 

2,305 

2,270

West Walker River, Calif.

C75- 69

- 68 

- 70

- 67 

- 66 

- 71

C75-115 

-113

-114 

-112

SW1/4NE1/4SW1/4,

SE1/4NW1/4SE1/4, 

NW1/4SW1/4NE1/4,

NE1/4SW1/4NE1/4, 

NW1/4NW1/4NW1/4, 

SE1/4SW1/4SW1/4,

SE1/4NW1/4NE1/4, 

SE1/4SW1/4NE1/4, 

NW1/4SE1/4NE1/4, 

NW1/4SW1/4NW1/4,

sec

sec 

sec

sec 

sec 

sec

sec 

sec 

sec 

sec

 21,

. 21, 

 23,

. 22, 

 5, 

 35,

 5, 

 9, 

 9, 

. 15,

T.

T. 

T.

T. 

T. 

T.

T. 

T. 

T. 

T.

6

6 

6

7 

6 

6

3 

3 

3 

3

N.,

N., 

N.,

N., 

N., 

N.,

S., 

S.,

S.,

s.,

R.

R. 

R.

R. 

R. 

R.

R. 

R. 

R. 

R.

23 E.

22 E. 

23 E.

23 E. 

23 E. 

24 E.

Wallowa

45 E. 

45 E. 

45 E. 

45 E.

Fales Hot 

Springs 15'.

Fales Hot 

Springs 15'. 

 d o 

 do 

 do 

Lake , Ore .

Sage, grass- 

 do 

 do 

 do 

 do 

 do 

Grass, sagePine, grass2,105

2,635 

2,195

2,220 

2,610 

2,105

1,340

1,500 

1,455

Grand Mesa, Colo.

C76- 01 

- 02 

- 03

C76- 18 

- 19 

- 21

0.2 km N. of Bonham 

SE1/4NW1/4SW1/4, sec 

NE1/4SE1/4SW1/4, sec

NE1/4SE1/4SW1/4, 

NE1/4SW1/4SE1/4, 

NW1/4NE1/4SW1/4,

sec 

sec 

sec

Reservoir

. 4, T. 

. 3, T.

. 24, 

. 21, 

 33,

T. 

T. 

T.

12 

12

8 

9 

9

s.,

s.,

s., 

s., 

s.,

R. 

R.

R. 

R. 

R.

96 W. 

96 W.

Siletz

11 W. 

10 W. 

9 W.

Grand Mesa 

7 1/2'. 

Lands End 

7 1/2'. 

Skyway 7 1/2' 

River, Ore.

Euchre Mt. 15' 

Toledo 15' 

Sprue e-fir 

Grass, spruce 

Spruce, grass

Mixed forest 

 do 

2,980 

3,140 

3,185

15 

20 

65

Spokane, Wash.

C76- 50 SE1/4SW1/4NE1/4, sec. 29, T. 25 N., R. 42 E. Medical Lake 15' Grass 705
54 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Site No. Location Topographic map Vegetation Altitude 

(m)

Soil 

PH 1

South Fork Shoshone River, Wyo.

C76- 76 1.5 km E. of mouth of Ishawooa Creek- Ishawooa 15'- Grass- 1,890

Warm River Butte Area, Idaho, Wyo.

C78-100

-101

-102

-108

-109

-103

-106

-107

- 98

- 99

-104

- 97

-105

0.6 km NNW. of Bechler River Ranger Station Warm River Butte

15', Idaho-Wyo.

1.0 km NNW. of Bechler River Ranger Station do 

NE1/4NW1/4NE1/4, sec. 11, T. 9N., R. 45 E. do - 

NW1/4NE1/4NW1/4, sec. 3, T. 47 N., R. 118 W. do - 

NW1/4SE1/4NW1/4, sec. 4, T. 47 N., R. 118 W. do -

NE1/4NE1/4NW1/4, sec. 19, T. 9 N., R. 45 E. 

NE1/4NW1/4NW1/4, sec. 3, T. 8 N., R. 45 E.

 do-

 doNW1/4NE1/4NE1/4, sec. 2, T. 8 N., R. 45 E. do - 

NW1/4NE1/4NW1/4, sec. 33, T. 47 N., R. 118 W. McReynolds Res.

7 1/2', Idaho-Wyo. 

NE1/4SW1/4SW1/4, sec. 28, T. 47 N., R. 118 W. Warm River Butte

15', Idaho-Wyo.

NW1/4NW1/4SE1/4, sec. 24, T. 10 N., R. 44 E. do - 

SE1/4NE1/4SE1/4, sec. 32, T. 8 N., R. 44 E. Drummond 7 1/2',

Idaho. 

SW1/4SW1/4NW1/4, sec. 5, T. 8 N., R. 45 E. Warm River Butte

15', Idaho-Wyo.

Pine 

 do 

Pine, aspenPine, grassGrass, pineFir, aspen,

sage. 

Pine, aspen,

grass.

Pine 

Aspen, grassSage, grass 

1,966

1,969

1,868

1,960

1,966

1,743

1,902

1,935

2,109

2,097

1,878

1,783

Grass, pine 1,993

1:1 soil-water mixture, <0.2 mm fraction; leaders ( ), not measured.

APPENDIX C. GENERALIZED PETROGRAPHIC DESCRIPTIONS

The following are generalized petrographic descriptions of the rock types in each of the major study areas 

on which weathering rinds were measured.

BASALTS 

WEST YELLOWSTONE

Basalts examined near West Yellowstone, Mont., 

were derived from the Madison River Basalt (Christiansen and Blank, 1972). The rocks contain scattered 

phenocrysts of plagioclase as much as 1 mm long, and 

less commonly phenocrysts of olivine as much as 

0.5 mm in diameter, locally in glomeroporphyritic 

clusters. The matrix consists of plagioclase, in laths 

0.1-0.2 mm long; crystals of clinopyroxene, olivine, 

and opaque minerals, about 0.05-0.1 mm in diameter; 

and irregular-shaped masses of basaltic glass and 

chlorophaeite. Matrix textures are mostly intergranular to intersertal, and less commonly 

subophitic. Visual estimates of the modal composition 

are: plagioclase, 45-55 percent; pyroxene, 25-30 percent, olivine, 5-10 percent; glass and chlorophaeite, 

5-10 percent; and opaque minerals about 10 percent.

McCALL

Rocks examined near McCall, Idaho, are extremely 

uniform in texture and composition and are probably 

derived from the upper part of the Yakima Basalt 

Subgroup of the Columbia River Basalt Group (John 

Bond, oral commun., 1976). The rocks are mostly 

aphanitic, consisting of plagioclase laths 0.1 to 

0.2 mm long (with scattered microphenocrysts up to 

0.5 mm long); crystals of clinopyroxene, olivine, and 

opaque minerals 0.05-0.01 mm in diameter; and 

irregular-shaped masses of glass, chlorophaeite, and 

calcite. The textures are mostly intersertal to 

hyaloophitic; less commonly intergranular to 

subophitic. Visual estimates of the modal composition 

are plagioclase, 45-55 percent; pyroxene, 20-30 percent; olivine, 0-5 percent; calcite, 0-5 percent; glass 

and chlorophaeite, 15-20 percent; opaque minerals, 

10-15 percent.
APPENDIX C 55

YAKIMA VALLEY

Rocks examined from the Yakima Valley are derived 

from the Eocene Teanaway Basalt (Foster, 1958; 

Porter, 1975). They are mostly aphanitic, but some 

contain scattered phenocrysts of plagioclase or opaque 

minerals 0.3-0.5 mm in longest dimension. Grain size 

generally ranges between 0.05 and 0.2 mm, and textures are mostly intersertal; less commonly textures 

are intergranular, hyaloophitic, and subophitic. Visual 

estimates of the modal composition are: plagioclase, 

some of which is zoned, 45-55 percent; clinopyroxene, 

25-35 percent; oh"vine, 0-10 percent; opaque minerals, 

5-10 percent; glass, chlorophaeite, and (or) chlorite, 

10-20 percent; and rare (<1 percent) potassium 

feldspar.

PUGET LOWLAND

The precise source of the basalt in the Puget 

Lowland drifts is not known, but it is probably mostly 

derived from the Eocene Crescent Formation in the 

Olympic Mountains. The basalt contains 

microphenocrysts of plagioclase, 0.5-0.8 mm long, 

and clinopyroxene, 0.3-0.5 mm in diameter. The 

matrix consists mostly of thin plagioclase laths 

(0.3-0.5 mm long); equant clinopyroxenes 

(0.05-0.1 mm in diameter); and irregular-shaped 

masses of devitrified glass, chlorophaeite, and chlorite. 

Glass is rarely present. Textures are mostly intersertal, less commonly hyaloophitic. Visual estimates of 

the modal composition are: plagioclase, 40-55 percent; 

clinopyroxene, 25-35 percent; oh"vine, 0-1 percent; 

opaque minerals, 5-10 percent; and altered glass and 

chlorite, 10-20 percent.

ANDESITES

Weathering rinds from sampling areas containing 

andesitic rocks were measured on two groups of 

stones: "coarse grained" and "fine grained." The two 

textural groups represent an arbitrary field classification based on phenocryst content and matrix texture. 

See p. 12 for definition of these textural groups.

MOUNT RAINIER

Most of the rocks examined from the Mount Rainier 

area were derived from andesite of the Mount Rainier 

volcano (Fiske and others, 1963), although some 

weathering rinds were measured on stones derived 

from older volcanic rocks. The andesite of the Mount 

Rainier volcano is a hypersthene andesite and is 

remarkably uniform in composition.

The fine-grained andesites contain scattered 

phenocrysts 0.5-1.5 mm in largest dimension, 

whereas microphenocrysts 0.1-0.3 mm long are more 

abundant. Plagioclase is the most abundant 

phenocryst, with lesser amounts of pyroxene, and a 

few crystals of amphibole and olivine. Both the 

plagioclase and the pyroxene are typically zoned, with 

plagioclase showing a wide range in degree of zoning. 

Both ortho- and clinopyroxenes are present; slightly 

pleochroic orthopyroxene (hypersthene?) is more abundant. Amphiboles and some pyroxenes exhibit reaction 

rims of iron oxides. The matrix is very fine grained 

(0.01-0.05 mm in size) and appears to consist mostly 

of plagioclase, pyroxene, opaques, and glass. Visual 

estimates of the modal composition are: plagioclase, 

45-50 percent; pyroxene, 30-35 percent; opaques, 5-10 

percent; glass, 5-10 percent; amphibole, 0-1 percent; 

and oh"vine 0-1 percent. Textures are primarily 

hyaloopilitic.

Coarse-grained andesites are similar compositionally 

to fine-grained andesites. The grain size is highly 

bimodal, with abundant large (0.5-3.0 mm) 

phenocrysts of plagioclase and pyroxene, and rare 

phenocrysts of olivine and opaque minerals, in a very 

fine grained (0.01-0.03 mm) matrix. The pyroxene 

phenocrysts commonly occur in glomeroporphyritic 

clusters. Textures range from hyaloopilitic to pilotaxitic.

LASSEN PEAK

Rocks examined from the Lassen Peak area were 

derived from a variety of andesitic flows which make 

up the volcanic complex around Lassen Peak 

(Williams, 1932). The mineralogy of these andesites is 

moderately variable.

The fine-grained andesites are nonporphyritic to 

weakly porphyritic. Phenocrysts, if present, range 

from 0.3 to 1.5 mm in size; plagioclase (some of which 

is zoned) is generally the largest and most abundant 

phenocryst; phenocrysts of clino- or orthopyroxenes 

and olivine are less common. The matrix is typically 

fine grained (0.08-0.1 mm) and consists of plagioclase, 

pyroxene, opaque minerals, glass, and rarely calcite, 

potassium feldspar, and olivine. In rocks containing 

calcite or olivine, clinopyroxene is more abundant than 

orthopyroxene. Textures are mainly pilotaxitic to intergranular. Visual estimates of the modal composition are: plagioclase, 40-60 percent; pyroxene, 25-40 

percent; opaques, 5-10 percent; glass, 0-15 percent; 

potassium feldspar, 0-10 percent; calcite, 0-5 percent; 

and oh"vine, 0-15 percent.

The coarse-grained andesites have similar mineralogy, except that they contain very little glass.
56 WEATHERING RINDS AS A QUARTERNARY AGE INDICATOR, WESTERN UNITED STATES

Phenocrysts are abundant, the most common being 

plagioclase (1.0-2.0 mm long), which is commonly 

zoned. Pyroxene (clino- more abundant than ortho-) 

and oh"vine phenocrysts range from 0.6 to 1.2 mm in 

size. The matrix grain-size is about 0.1-0.2 mm. Textures are mostly intergranular to pilotaxitic.

TRUCKEE

The rocks examined from near Truckee, Calif., were 

derived mostly from the late Tertiary andesites that 

are abundant in the area. A few basalt clasts (those 

without olivine phenocrysts) from the Pliocene and 

Pleistocene Lousetown Formation (Birkeland, 1963) 

may have been included with the fine-grained 

andesites.

The fine-grained andesites contain microphenocrysts 

0.1-0.3 mm in size and a few scattered phenocrysts up

to 2 mm in size. The phenocrysts are plagioclase, 

pyroxene, olivine, and amphibole in varying proportions; the microphenocrysts are plagioclase (most 

abundant) and pyroxene. A few of the plagioclase and 

pyroxene phenocrysts are zoned. Clinopyroxene is 

commonly more abundant than orthopyroxene. The 

matrix is very fine grained (0.02-0.07 mm) and consists mostly of plagioclase, pyroxene, and opaque 

minerals. Glass is scarce. Visual estimates of the 

modal composition are: plagioclase, 50-65 percent; 

pyroxene, 20-35 percent; opaques, 5-10 percent; 

oh'vine, 0-10 percent; amphibole, 0-5 percent; glass, 

0-5 percent. Textures are primarily pilotaxitic to 

trachytic.

The coarse-grained andesites are similar mineralogically and texturally to the fine-grained andesites. They 

contain abundant phenocrysts of plagioclase and 

pyroxene 0.5-2.0 mm in size, in a matrix whose grain 

size is generally 0.01-0.1 mm.

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