Chronology of 

Emplacement of Mesozoic 

Batholithic Complexes 

In California and 

Western Nevada 

By J. F. EVERNDEN and R. W. KISTLER 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 623 

Prepared in cooperation with the 

University of California (Berkeley) 

Department of Geological Sciences 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970 
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

Library of Con;gress CSJtalog-card No. 7s-.60.38'60 

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

Washington, D.C. 20402 - Price $1.25 (paper cover) 
CONTENTS 

Page 

Abstract-------------------------------~---------------------------------------------------------------------- 1 

Introduction--------------------------------------------------------------------------------~----------------- 1 Analyt:cal problems ____________________ -._______________________________________________________________________ 2 

Analytical procedures______________________________________________________________________________________ 2 

Precision and accuracy ___________________ -.- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2 

Potassium determinations_______________________________________________________________________________ · 2 

Argon determinations--------~------------------~------------------------------------------------------ 5 

Chemical and crystallographic effects on potassium-argon ages----------.----------------------------------------- 6 

Apparent age as a function of c.hlorite content of biotite __________________ -------___________________________ 6 

Apparent age as a function of mineral type ______________________ ·----------------------------------------- 7 

Apparent potassium-argon ages of quartz from granitic rocks _________________________________ ----------_____ 7 

Geologic interpretation __ ---- ________________ ----- ______________ ------- __________________ ------ _________ ·________ 9 

Genetic significance of potassium-argon ages of biotite and hornblende _______________________ · _________ - ___ ----____ 9 

Potassium-argon age in plutons of Cathedral Peak type----------------------------------------------------- 9 

Depth of emplacement of the Sierran plutons-------:------------------------------------·------------------- 12 

Discordant biotite-hornblende pairs-evidence of rehea~d plutons ____ -------________________________________ 15 

Concordant biotite-hornblende pairs-evidence of the age of an intrusive event________________________________ 16 

Growth of the Sierra Nevada batholith ______________________________________________________________ -____ 16 

Cathedral Range intrusive epoch of·Late Cretaceous age _______ : ___________________ .:-----------~-------- 17 

Huntington Lake intrusive epoch of Early Cretaceous age _________ -_- _____________________ -_- __ --_-____ 17 

Yosemite intrusive epoch of Late Jurassic age--------------------------------------------------------- 17 

Inyo Mountains intrusive epoch of Early and Middle Jurassic age-----------------------~·--------------- 18 

Lee Vining intrusive epoch of Middle and Late Triassic age--------------------------------------------- 19 

Summary of ages in all intrusive epochs _______________________ ~_- ______________________ -- ____ ---- ___ - 19 

Uplift of plutons of the transverse and Coast Ranges-------------------------------------·---------------------- 21 

Granite emplacement and sedimentation on the continent------------------------------------------------------- 22 

Correspondence of intrusive and deformational events in the Sierra Nevada _________________________ --- ___ ---- __ -- 25 

Conclu~ons------------~-------------------------------------------------------------------------------------- 26 

References cited-------~------------ -------------------------------------------------------------------------- 26 

ILLUSTRATIONS 

Page 

PL,\'l'E 1. Map showing distribution of Mesozoic granitic rocks in California and western Nevada _____ ------------- In pocket 

2. Map showing potassium-argon age of biotite and (or) hornblende for each locality shown on plate L __ ---- In pocket 

FIOUll.E 1. Histograms of 8(.z- 11> values _________________________________________________ .:. ____________ ------------- 3 

2. Sketch map showing potassium-argon dates on samples from plutons of Cathedral Peak type, Sonora and Cathedral 

Peak plutons----------------------------------------------------------------------------------- 10 

3. Sketch map showing potassium-argon dates on samples from plutons of Cathedral Peak type, Recess and Whitney 

plutons _______________ .:.---------------------------------------------~-------.:.------------------ 11 

4. Graph showing pressure-temperature fields for metamorphic mineral and rock pairs ________ ----------------- 13 

5. Graphic representation of heat model for intrusive rocks of the Sierra Nevada _________________ - ____ ---- __ -- 14 

6. Rubidium-strontium isochron plots for granitic rocks in California ________________________________ ----____ 18 

7. Diagram showing potassium-argon mineral ages and rubidium-strontium whole-rock ages for the Lee Vining, 

Yosemite, Huntington Lake and Cathedral Range intrusive epochs ___________________________ --_-____ 20 

H. Diagram showing potassium-argon mineral ages and ru.bidium-strontium whole-rock ages for granitic rocks of 

the lnyo Mountains, Yosemite, Huntington Lake, and Cathedral Range intrusive epochs________________ 21 

n. Diagram showing relation of sedimentation in the Sacramento Valley to granite emplacement in the Sierra 

Nevadaarea------------------------------------------------------------------------------------ 23 

10. Curve showing extent of epicontinental seas and Mesozoic and Cenozoic time scale __________________ -_- __ -_ 24 

III 
IV CONTENTS 

TABLES 

Page 

TABLE 1. Potassium-argon ages of minerals with duplicate argon analyses__________________________________________ 5 

2. Data showing variation of potassium-argon age with variation in chlorite content in biotite__________________ 6 

3. Multimineral analyses (of same rock)----------------------------------------------------------------- 8 

4. Rubidium-strontium analytical data ____ ·______________________________________________________________ 19 

5. Potassium-argon analyses and location of sample localities----------------------~------------------------ 31 

6. Rock name and description of sample locality__________________________________________________________ 35 
CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN 

CALIFORNIA AND WESTERN NEVADA 

By J. F. EVERNDEN 1 and R. W. KisTLER 

ABSTRACT 

Ar40/K40 was determined for minerals from specimens of Mesozoic granitic rocks collected at 250 localities in California and 

western Nevada. Analytical reproducibility of Ar40/K40 in common minerals from granitic rocks was tested in the la·boratories 

of t'he U.S. Geological Survey and University of California 

(Berkeley), and the results were studied for interpretation of 

the genetic significance of potassium-argon ages derived from 

the rrutios. 

The potassium-argon ages of minerals from Mesozoic granitic 

rocks in California have a continuity from 210 to. 80 million 

years ago. However, a distinct periodicity of magma generation 

nnd intrusion is shown when the ages are related to the distribution of·genetic groups of plutons based on geologic mapping. Five 

epochs of magma generation and emplacement that took from 

10 to 15 million years to complete were initiated at approximately 30-million year intervals. Each intrusive epoch was 

preceded by, or was in part contemporaneous with, a period of 

regional deformation in California or western Nevada. These 

intrusive epochs and their ages are: 

Maximum to minimum age 

(m.fl.) Geologic age Intrusive epoch 

9Q-79. ___ --- _ Late Cretaceous ___________ Cathedral 

Range. 

121-104. _ _ _ _ _ _ Early Cretaceous__________ Huntington 

Lake. 

148-132. _:..- ___ L.ate Jurassic _____________ Yosemite. 

180-160 _______ Early and Middle Jurassic __ lnyo Mountains. 

21Q-195 _______ Middle and Late Triassic ___ Lee Vining. 

INTRODUCTION 

The motivations for this study derive both from the 

desire to investigate and document further the influence 

of various factors on the precision and accuracy attainable in the measurement of potassium-argon ratios in 

minerals of granitic rocks and from an interest in the 

problem of genesis and emplacement of pluton complexes such as those of California and western Nevada .. 

Study emphasis is on the well-exposed Sierra Nevada 

batholith in California. 

It must .be made clear that precision and accuracy as 

used here refer only to problems of potassium and argon 

measurement and not to the meaning of "apparent 

1 Present affiliation, Advanced Research Projects Agency, Washington, D.C. 

ages." Accepting this as the only possible meaning to 

be signified by plus or minus estimates on determined 

"ages," there is very little documentation of factors 

influencing such plus or minus estimates. Moreover, 

highly variable statements are still made by different 

investigators with little or no supporting data. Some 

investigators report ages with "probable errors of about 

5.'percent," while others imply precision of 1 percent. 

The data of the present paper clearly show the influence 

of diverse factors on precision and accuracy of 

potassium-argon ages. The investigation of determined 

potassium-argon ratios as a function of mineral alteration or other factors has indicated the necessity of considering such factors in the interpretation of derived 

"ages." 

Data previously presented ( Evernden and Richards, 

1962) on the Paleozoic batholiths of eastern Australia 

strongly suggested that there had been continuity of 

granite generation and emplacement over a period of 

some 200 million years. The locus of batholithic intrusion moved more than 300 km, but the "ages" obtained 

implied the virtual lack of any cessation of emplacement of granitic magma during that long interval. On 

the other hand, previous interpretations of ages of 

granitic rocks from the Sierra Nevada of California 

have implied at least two distinct periods of granite 

emplacement (Curtis and others, 1958). Kistler, Bateman, and Brannock (1965) have suggested three 

possible age groups. 

We show that the patterns of ages of granitic rocks 

in the Sierra Nevada, taken altogether, have a continuity similar to that of the ages of granitic rocks in 

eastern Australia. However, a distinot periodicity of 

magma generation and intrusion is shown when potassium-argon and rubidium-strontium ages are related to 

the distribution of genetic groups of plutons based on 

geologic mapping. We also show that the thermal 

history of individual plutons is reflected in their mineral 

ages and that, with a few assumptions, the data permit 

estimates of the crustal level of emplacement of the 

plutons. 

An essential assumption in the discussion that follows 

1 
2 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

is that the "ages" obtained by potassium-argon analysis 

result primarily from a more or less complex cooling history for each pluton and mineral. Virtually all investigators have concluded that the plutons of the Sierra 

Nevada are the product of magmatic emplacement. In 

fact, the pattern of ages obtained seems to be inconsistent with any other interpretation. Assuming this and 

assuming no later reheating of the rock, then at best the 

potassium-argon age of a minera:l from the rock will be 

a determination of the time when this magma mass had 

cooled sufficiently to allow retention of argon in the 

crystal lattice. Because of . pronounced difference in 

diffusion rate in relation to temperature for argon in 

biotite and hornblende (Hart, 1964), the amount of discordance between biotite and hornblende ages from rocks 

will be, in some sense, a measure of the cooling rate of 

the pluton. Thus, concordance of the8e two ages implies 

rapid cooling and a near approach of the determined age 

to the time of initiation of cooling of the pluton. On the 

other hand, reheating of the sample by later intrusion 

will result in partial or complete loss of previously generated argon and will often give rise to marked discordance in biotite and hornblende ages. If the pattern of 

discordance is accurately delineated, conclusions about 

the pattern of growth of the pluton complexes become 

possible. 

Many of the samples collected for this study are from 

areas that are virtually unmapped in terms of delineation of individual plutons. This is unfortunate, but we 

point out that the great span of time, Late Triassic to 

Late Cretaceous, represented by the Mesozoic intrusive 

rocks of Calif~rnia, is demonstrated mainly by the data 

of geochronometry and not by stratigraphic correlation. 

In fact, even in areas of detailed ·mapping, the ages of 

intruded rocks are so poorly known, or stratigraphic 

columns have such large gaps, that geologic assignment 

of ages of intrusive rocks is usually possible only within 

the limits of two or more geologic periods. It was decided, therefore, that questions of sufficient interest for 

this study could be answered without further detailed 

field control, while such a pattern of dates .as here demonstrated may act as a stimulus to field investigations. 

Prior to the writing of the paper, we had been dating 

rocks independently in different areas of the Sierra 

Nevada and adjacent batholiths of California and western Nevada as part of work at the University of California (Berkeley) and the Geological Survey. In order 

to present as comprehensive a report as is possible at 

present and to facilitate the publication of the large 

mass of data gathered, we combined our efforts for this 

paper. 

The discussions separate logically into two parts. The 

first part deals with analytical problems such as the 

precision and accuracy of potassium measurements (a 

similar treatment for argon measurements is to he found 

in Evernden and Curtis, 1965) and the influence of 

chemical and mineralogic factors on apparent potassium-argon ages. The second part is the geologic interpretation of the total body of the absolute age data. The 

two parts can be read as nearly separate papers. 

ANALYTICAL PROBLEMS 

ANALYTICAL PROCEDURES 

Standard analytical techniques for potassium and 

argon used at the Ut:1iversity of California (Berkeley) 

are described in Evernden and Curtis ( 1965) ; similar 

techniques used by the U.S. Geological Survey are described in Kistler and Dodge ( 1966). Precision and accuracy obtained for potassium-argon ages at UC 

Berkeley ha.ve been reported by Evernden, Savage, 

Curtis, and James ( 1964) ; those obtained by the Geological Survey by Kistler ( 1968). 

The rubidium-strontium analyses of granitic rocks 

that are reported in this paper were made by Carl Hedge 

or by Kistler. Rubidium and strontium were determined 

by standard isotope dilution techniques and by X-ray 

fluorescence analyses. 

Localities of all ana.lyzed specimens are shown on 

plate 1 and are tabulated in table 5 of this report. Potassium-argon ages of biotite and (or) hornblende are 

shown for each locality on plate 2. Potassium-argon 

analytical data are tabulated in ta:ble 5 and rubidiumstrontium analytical data are tabulated in table 4. Rock 

names and descriptions are given in table 6. 

PRECISION AND ACCURACY 

POTASSIUM DETERMINATIONS 

All potassium analyses a.t UC Berkeley were made by 

means of a flame photometer with a propane flame. The 

galvanometer was replaced by oite.having greater precision of movement. NH40H and (NH4) 2C03 are made 

in the laboratory ; all other chemicals ate reagent grade. 

All measurements are made against carefully buffered 

standards; all new determinations are made in duplicate; and with every set of four new determinations, a 

repeat of a previously analyzed specimen is performed. 

Blank runs now yield values between 0.013 and 0.018 

ppm potassium in 200-cc solution. 

The problem to be approached first is that of repro- . 

ducibility of results by the technique used. The first 

requirement of such an evaluation is the use of a concentrate of very high purity. As will be demonstrated 

below, this is not easily obtained. However, one such 

concentrate of leucite has been available in large quan-
ANALYTICAL PROBLEMS 3 

tity and 31 analyses on it were run during 33 months. 

The average potassium value was 15.793 percent with 

the standard deviation of a single determination equal 

to 0.020, or the coefficient of variation of a single determination equal to 0.13 percent. These calculations were 

based upon normal distribution theory, but no single 

determination departed from the mean by more than 

0.25 (twice the coefficient of variation). Another sample, 

NBS 99, was run 21 times during the same period of 

time with a mean potassium value of 0.331 percent; the 

standard deviation of a single determination was 0.002 

percent, and the coefficient of variation was 0.6 percent 

(samples dried at 105°C for 24 hours). Neither of these 

series showed an observable drift of determined potassium value with time, although the standard solutions 

have been stored in polyethylene bottles with screw tops. 

Other shorter series also support the conclusion that, on 

materials of high purity or uniformity containing several percent potassium, the coefficient of variation of a 

laboratory's precision should be a small fraction of 1 

percent, and at the 90-percent cop.fidence level, below 

1 percent. 

To achieve as high purity in the biotite concentrates 

as was consistent with reasonable expense, samples were 

handpicked under a binocular microscope in the size 

ranges 10/16 and 16/28 Tyler mesh (exceptions to these 

size ranges are noted in table 5). All samples. were run 

in duplicate. For statistical purposes, if all biotite 

samples were considered equal in regard to variability within the concentrates, then all samples should 

hav~ the same coefficient of va;riation. We can treat the 

data as two independent sets of determinations, Set 1 

(w) being the first value for each of the 141 samples, 

and Set 2 (y) the second value. The complete independence of Set 1 and Set 2 allows· us to write 

Observed values of (x-y) yield u~~-u> =0.1752 percent 

or o-~=0.296 percent and u~z+u>/ =0.210 percent (all u' 

values being coefficients of variation). 

Thus the coefficient of variation of the mean of the 

two determined values is, according to normal distribution theory as applied to all of the data, two-tenths of 

1 percent, and the coefficient of variation of a single 

determination is 0.3 percent. Two points should be 

noted: the ua:' value is higher ·than would be expected 

from a consideration of the leucite data, and the 

( w- y) values do not show a normal distribution 

(fig. 1). These facts suggest that the pattern of figure 

1 is not controlled solely by laboratory reproducibility 

but that additional factors are influencing the distribution. Chlorite content of the biotite grains seems to be 

the explanation. We have previously noted that it is 

impoSsible to obtain uniform splits of nonuniform 

samples. Many of the samples concentrated are from . 

rock which, in thin section, appeared practically useless 

because of extensive chloritization. However, by crushing a few pounds of rock and by carefully picking 

grains which displayed no obvious chlorite content 

under reflected light, samples with potassium values 

above 7 percent were obtained in most cases. Biotite 

20 

0+---------.---------.---------.---------.---------~ 

0 0.2 0.4 0.6 0.8 1.0 

0 

o (x-y) 

Picked Hornblende (57 samples) 

(2 at 1.0-1.5) 

0.2 0.4 0.6 0.8 

o (x-y) 

Picked Biotite (140 samples) 

1.0 

N 1~ l! ~ ....._______,__! 

0 0.5 1.0 1.5 2.0 2.5 

O(x-y) 

Unpicked Biotite (20 samples) 

FIGURE !.-Histograms of 8<,-v> values. N is number of 

samples. 
4 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

books from such rocks often contain appreciable chlorite 

detectable only by further disaggregation of the books. 

Three lines of evidence suggest that this chlorite content is the explanation of the high u' computed. Firstly, 

the observed (x-y) values are a function of potassium 

content of the biotite; the mean of all samples with 

8<x-v> less than 0.1 percent is 7.6 percent potassium, 

whereas the mean of all samples with B<x-v> greater than 

0.5 percent is 7.3 percent potassium (8<x-v> being (x-y) 

expressed as percent of the potassium value). Secondly, 

the B<x-v> values are a function of the sample and are not 

randomly distributed throughout the set of determinations. The evidence for this was obtained by repeated 

potassium analyses. Four samples with 8<x-v> less than 

0.1 percent and four with B(X-Y) greater than 0.5 percent 

were rerun in duplicate; the second B<x-v> values are 

here termed B<x-v>n· 

KA 1540 ________________________________ _ 

1568--------------------------------- 1573 ________________________________ _ 

1575 ________________________________ _ 

1525 ________________________________ _ 

1537 ________________________________ _ 

1591--------------------------------- 1593 ________________________________ _ 

6(:o-u) 

(percent) 

0. 03 

. 05 

. 1 

. 04 

.7 

.8 

.8 

.9 

6(,.-u)n 

(percent) 

0. 1 

. 09 

. 01 

. 09 

.6 

.. 5 

.8 

.6 

Thirdly, .several samples with 8<x-v) values below 0.1 

percent and above 0.5 percent were crushed and examined under the petrographic microscope. Invariably, 

those with high values of 8cx-v> showed appreciable chlorite, whereas those with low values of 8cx-v> showed little 

or no chlorite. A further demonstration of this correlation of high 8cx-v> values with low potassium content 

and thus with appreciable chlorite and resulting inhomogeneity of sample is obtainable by comparing the potassium and 8cx-v> values of picked and unpicked (P and 

U) samples in table 5 (allBcx-v> values are there rounded 

to the closest tenth percent) and by inspection of figure 

1. It appears that the correlation of 8cx-v> values and 

chlorite content is established ·and that such chlorite 

content degrades the precision or accuracy obtainable. 

We suggest, therefore, that all reported potassiumargon ages should include as an essential piece of information the 8cx-v> values for e-ach age determination, 

assuming that duplicate potassium analyses are performed. Note that virtually all the hornblendes have 

8cx-v> values of several tenths of 1 percent or higher 

(fig. 1), indicating a. lower precision and accuracy for 

these "ages" than for the biotite ages. 

Interlaboratory comparisons based upon samples 

showing high values of 8cx-v> are pointless because it 

becomes ·difficult or impossible to separate laboratory 

differences from sample variation. 

The main geologic conclusions of this paper will be 

based upon a study of the relative ages of both biotite 

and hornblende obtained for the numerous samples. As 

all the biotites and hornblendes are similar chemically 

there is no reason to expect that the results of flamephotometry procedures have significant errors in relative values greater than those of the analytical precision discussed above. Errors in ·analysis by flame 

photometry are of a systematic character, not random. 

Cro~checks against other la-boratories and against results from different analytic:al techniques yield estimates 

of the accuracy of the de.termined potassium values, and 

thus of the accuracy ohta;inable with the procedures 

used. The following da;t;a have been recently obtained 

in a continuing effort to evaluate accuracy : 

1. UC Berkeley values (Evernden and Curtis, 1965) on 

biotite B 3203, 7.54, 7.57, 7.58, and 7.56 percent K, 

which are in good agreement with other published 

values (for ex·ample, see Hart, 1964, who reports 

a K value of 7.56 percent) . 

2. Results on samples run at both the University of California (Berkeley) and the Geological ·survey by 

flame photometer but using different preparation 

procedures, and results of Survey analysis of 

aotinolite and aegerine augi·te by atomic absorption 

(see unnumbered table). 

Flame photometer results on samples run at both University of 

California (Berkeley) and the U.S. Geological Survey 

Sample 

Atomic K (USGS) Flame pho- absorp- tometer (percent; all K (UC Berkeley) Flame 

tion values represent average photometer (percent) (percent) of two determinations) 

B 53-15A 0. 060 0. 060 0. 0626 ( 0. 0639, 0. 0634, 

(actinolite). 0.0609,0. 0621) 

FD-13 (plagi- oclase) _____________ . 267 . 272 (0. 271, 0: 272) 

CL-1 (plagio- clase) ______________ . 329 . 324 (0. 3205, 0. 3279) 

422-H (aegerine augite) ___ 0. 54 . 054 0. 54 ( 0. 0534, 0. 0546, 

0. 0536,0. 0543) 

KA 1508-B 

(biotite) ____________ 7. 51 7. 55 (7. 53,7. 57) 

KA 1566-B 

(biotite) ____________ 7. 36 7. 55 (7. 53, 7. 57) 

FD-13 (bioti te) _____ - - _ - _ - __ - - - 7. 75 7.86 (7. 85, 7. 86) 

3. Feldspars analyzed at UC Berkeley by two techniques: flame photometry (by J. Hampel) and 

X-ray fluorescence .(by R. Jack); results are tabulated and shown in percent (see unnumbered 

table). A comparison of columns 5 and 6 of the 

table suggests ·a correlation, as the mean l for 
ANALYTICAL PROBLEMS 5 

8<a:-v> less than 0.5 is 0.32, whereas the mean l for 

8<a:-v> equal to or greater than 0.5 is 1.27. This agrees 

with the conclusion drawn from the biotite data; 

that is, large 8<a:-v> values are associated with nonuniform samples. 

Feldspar analyses made by University of California (Berkeley) 

2 3 4 6 

Sample K (F/P) K (X/R)[G-1] K (X/R)[ADJ] E ' a<·-·> 

KA 1040_ 2. 562 2. 546 0. 62 2. 558 0. 15 0. 2 

1044_ 2. 569 2. 554 . 58 2. 566 . 10 .2 

1053_ 3. 237 3. 225 . 37 3. 243 -.18 .4 

1041_ 3. 245 3. 266 -. 34 3. 274 -. 89 .6 

1029_ 3. 949 3. 893 1. 42 3.917 ·' 82 .6 

105L 4. 203 4. 164 . 93 4. 190 . 32 .8 

1017_ 4. 724 4. 630 1. 82 4. 669 1. 16 .6 

4. 646 

1090_ 4. 962 5. 048 -1.73 5. 081 -2.40 ~6 

1178_ 5. 253 5. 250 . 06 5. 286 . 63 .2 

1089_ 5. 290 5. 249 . 78 5.286 . 08 .2 

1054_ 5. 307 5. 363 -1.06 5.400 -1.76 .7 

1193_ 5. 390 5. 391 . 02 5. 354 . 67 .4 

1365_ 5. 798 5. 731 1. 16 5. 774 . 42 .2 

G-1_ 4. 600 114.499" 2. 2 4. 529 1. 55 .5 

1. Potnsslum values obtained by flame photometry. 2. Potnsslum values obtained by X-ray fluorescence, nssumlng a K value of 4.499 

percent for G-1. 

3. (Column 1 - Column 2) X100/Column 1. 

4. J>otnsslum values obtained by X-ray fluorescence, cnlibration being controlled 

by plot of Column 1 versus Column 2 and adjustment indicated. 

5. (Column 1 - Column 4)X100/Column 1. 6. ])!Uorence between tho two K values obtained by flame photometry, expressed as percent of K value. 

4. Potassium analyses repeated after 6 years on unpicked biotite samples. New runs have numbers 

ending in ( -64) : 

Run No _____ .____ KA 67 KA 67-64 KA 71 KA 71-64 KA 72 KA 72-64 

K ________ (porcont) 7. 09 7. 21 7. 55 7. 52 7. 53 7. 59 

Both runs were performed on flame photometers, but 

by somewhat different preparation procedures. 

ARGON DETERMINA~IONS 

Argon an·alyses are not routinely repeated. Control on 

argon precision and accuracy is obtained by repeats on 

several selected samples and by doing large numbers of 

genetically or temporally related samples. Thus, when 

da-ting volcanic rocks related to strata that yielded vertebrate fossils, the accuracy of the dates and other conclusions of the investigation were substantiated by a 

large body of age determinations related to many sites 

(Evernden ·and others, 1964). In the present investigation, several biotite samples were run in duplicate; 

in other words, splits of the same mineral concentrate 

were used in two independent argon analyses. All samples with numbers between l(A 1432 and KA 1713 were 

analyzed by using spikes from a single spike set; this 

procedure eliminates any possible reLative difference of 

3159-8'35 0-69--2 

age due to failure to intercaliorate different spike sets 

ruccurately. The data on repeat runs are given in table 

1 (all runs are on picked samples). The mean difference 

of the picked biotite paired runs is 0.68 percent of the 

age. If the anomalously high v.alue of KA 1608 is excluded, the mean difference is 0.48 percent. We can only 

suggest misweighing or undetected blow.-out as possible 

causes of the discrepancy of the KA 1608 pair. 

TABLE !.-Potassium-argon ages of minerals with duplicate argon 

analyses 

Run Mineral K 

(percent) 

KA 1508 _______ Biotite ________________ 7. 821 

1508-It-----------------------------------

1508-B ____ Biotite; second concen- 7. 549 

trate. 

1508-B-It .. ------------------------------- 1518 _______ Biotite ________________ 7. 571 

1518-It----------------------------------- 1526 _______ Biotite ________________ 7. 778 1526-It __________________________________ _ 

1538 _______ Biotite-------------~-- ~ 591 1538-Jt __________________________________ _ 

154L ______ Biotite ________________ 7. 705 

1541-It----------------------------------- 1548 _______ Biotite._______________ 6. 994 1548-It __________________________________ _ 

1566 _______ Biotite ________________ 7. 618 

1566-It ___________________ ~---------------

1566-B ____ Biotite; second concen- 7. 548 

trate. 1566-B-It __ - _________________ - - - _________ _ 1587 _______ Biotite ________________ 7. 623 1587-It __________________________________ _ 

1590 _______ Biotite. _______________ 7. 391 1590-It __________________________________ _ 

1608 _______ Biotite ________________ 7. 099 1608-It __________________________________ _ 

1442 _______ Hornblende; 28/48 . 4515 

Tyler mesh. 

1449 _______ Hornblende; 35/48 . 4512 

Tyler mesh. 67 _________ Biotite ________________ 7. 09 

67-64 ___ ,;, __ Biotite; same concen- 7. 21 

trate, rerun, 6 years 

later, unpicked. 71 _________ Biotite ________________ 7. 55 

71-64 ______ Biotite; same concen- 7. 516 

trate, rerun, 6 years 

later, unpicked. 72 _________ Biotite. _________ M _____ 7. 59 

72-64 ______ Biotite; same concen- 7. 531 

trate, rerun, 6 years 

later, unpicked. 

40 

"Age" Ar a& 

(m.y.) (percent) 

86. 8 7 

86.6 8 

88. 9 6 

89. 0 7 

87. 1 14 

87. 4 15 

82. 4 8 

83. 7 7 

83.0 5 

83. 6 8 

94. 4 6 

94. 0 7 

81. 5 9 

81. 8 6 

87.8 9 

88.2 10 

88. 7 9 

88. 2 10 

78.4 4 

78.4 10 

81. 9 11 

81. 5 16 

90.5 15 

93. 2 10 

143 32 

142 14 

91. 0 13 

93. 3 9 

88.5 7 

92. 9 9 

87. 8 17 

90.0 11 

By duplicate analysis of argon from biotite, sanidine, 

and plagioclase from four USGS sa:mples, the mean 

difference of paired runs is 1.3 percent of the age (Kistler, 1968). 

A cross check between UC Berkeley and the Geological Survey served to intercalibrate the data from the 

two laboratories: 40 FD-13 Biotite __________ UC Berkeley ______ 124.9X1Q-11 moles/gram ArRad 

40 USQS ____________ 126.0X1Q-11 moles/gram ArRad 
6 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

The UC Berkeley value represents a single determination, the USGS value the average of two analyses 

(125.3, 126.8). 

CHEMICAL AND CRYSTALLOGRAPHIC EFFECTS 

ON POTASSIUM-ARGON AGES 

APPARENT AGE AS A FUNCTION OF CHLORITE 

CONTENT OF BIOTITE 

The discussion so far has been concerned solely with 

the reproducibility of potassium and argon analyses of 

given mineral concentrates. A matter of real concern 

is the effect of grain size and (or) chemical composition 

on the apparent age of a mineral concentrate. (See the 

following section, "Apparent age as a function of mineral type," for discussion of comparisons of apparent 

ages obtained from different minerals of the same r~ck 

sample, specifically for the minerals biotite, hornblende, 

potassium feldspar, plagioclase, and quartz.) The influence of chlorite content on age was investigated by 

analysis of two biotite-samples, one only slightly chloritized (KA 1511), the other extensively chloritized (KA 

1527) . The results are shown in table 2. 

TABLE 2.-Data showing variation of potassium-argon age with 

variation in chlorite content in biotite 

Run 

Picked (P) K Age (.x-y) 

or unpicked Size (Tyler) (percent) (m.y.) (per- (U) cent) 

Few percent chlorite content in biotite books 

KA 151L __________ P 16/28 7. 438 97. 2 0. 1 1511-10/16 _____ lJ 10/16 6. 699 97.5 .7 1511-16/28 _____ lJ 16/28 6. 176 98. 5 . 1 1511-35/48 _____ lJ 35/48 6. 799 101. 4 .7 

1511-100/150 ___ lJ 100/150 7. 093 100.9 . 1 1511-HBD _____ P 35/60 . 876 124. 6 .5 

Very high chlorite content in biotite 

KA 1527 ___________ P 10/16 7. 602 81. 9 0. 0 1527-8/10 ______ lJ 8/10 7. 315 80. 2 .8 1527-10/16 _____ lJ 10/16 7. 166 80. 0 .4 1527-16/28 _____ lJ 16/28 6. 880 82. 0 .3 1527-35/48 _____ lJ 35/48 4. 344 85.7 . 1 1527-48/60 _____ lJ 48/60 3. 171 86.9 1.5 1527-60/100 ____ lJ 60/100 2. 825 84. 7 . 1 

1527-100/150 ___ lJ 100/150 1. 630 90.8 .6 1533-HBD __ . ___ P 28/60 . 670 84. 3 .0 

Unpieked means that. the biotite-chlorite concentrate 

·was obtained by sizing ·and by using heavy liquids and 

that all other easily identified grains were removed by 

picking, care being taken not to alter the biotite-chlorite 

in the concentrate. Therefore, the slight increase of' apparent age with decreasing grain size in KA 1511 cannot with certainty be separated from the possible presence of hornblende, although a 13 percent hornblende 

content would be required to explain the indicated increase in age in K,A 1511-100/150. Note that the hornblende in this rock (table 2, KA 1511-HBD) is older 

than the biotite. The selection of this biotite for size 

analysis was made on the basis of its low content of 

chlorite prior . to discovering the discordant biotitehornblende ages. These data are still in marked contrast to those from KA 1527. In the KA 1527 series, 

the concentration of chlorite in the small grain sizes · 

is clearly shown by the four- to five-fold decrease in 

potassium content with decreasing grain size. The 

apparent ages, though not rising in a perfectly systematic manner, increase by over 10 percent with the decrease of potassium. Run KA 1533-HBD, done on a 

hornblende sample taken from the same end of the same 

pluton as KA 1527 (Cathedral Peak pluton, see fig. 2), 

indicates that the increase in apparent age in the KA 

1527 series cannot be attributed to the included hornblende. Numerous samples from the south end of the 

Cathedral Peak pluton (fig. 2) have been analyzed with 

the apparent ages showing a seeming correlation with 

potassium content (all samples picked): 

Size K Age Elevation 

Run (Tyler (percent) (m.y.) (ft) 

mesh) 

KA 1527 ________________ 10/16 7.'602 81. 9 8,800 1533 ________________ 16/28 7. 545 82. 5 8,800 1531 ________________ 16/28 7.443 83. 6 9,000 1594 ________________ 16/28 7. 120 82.4 8, 700 1593 ________________ 16/28 7. 100 83. 4 10,900 1530 ________________ 10/16 7. 053 83. 7 9,000 

1528----------------- 16/28 6.845 84. 6 8,800 

Five samples. from the north end of the same pluton 

show the following relationship: 

Size K Age Elevation 

Run (Tyler (percent) (m.y.) (ft) 

mesh) 

KA 1598 ________________ 16/28 7. 598 80. 1 7,300 1597 ________________ 16/28 7. 435 80. 2 7,950 1595 ________________ . 16/28 7. 296 81. 0 11,000 1599 ________________ 16/28 7. 208 81. 4 9,000 1596 ________________ 28/48 6.979 81. 4 9,200 

The set from the north end may not be significant, but 

the set from the south end is certainly significant in 

light of the initial discussion of reproducibility of 

potassium and argon values. The suite of samples from 

the southern end of the pluton shows a strong correlation of potassium content and apparent age, as does the 

sequence of sized samples of KA 1527, a member of the 

suite. The explanation is not at all obvious. As a matter 

of fact, the correlation is exactly opposite to that expected. Much of the chloritization in these .rocks is a 

weathering phenomenon rather than the result· of deuteric processes. Furthermore, it would seem quite i,mpossible to explain the above data in terms of chlorite 

development at time of emplacement. The only possible 
ANALYTICAL PROBLEMS 7 

explanation must be in tenns of a weathering process 

which achieved more complete removal of potassium 

than argon during chloritization. This conclusion, in 

turn, would seem consistent only with many of the argon 

atoms being in non potassium (octahedral layer~) lattice 

sites, that is, sites less subject to destruction during 

· chloritization. Thus, we may have obtained definitive 

evidence that many argon at.oms are impelled into nonpotassium lattice sites by recoil at time of disintegration 

of the potassium and associated gamma-ray radiation. 

Whatever the explanation, the obvious conclusion is that 

an inverse correlation of apparent age and potassium 

content in biotites can occur. Previously published results (Evernden and others, 1964, p. 160) are not in 

disagreement with this conclusion, as the potassium 

values for the series reported there changed by only 

30 percent. 

APPARENT AGE AS A FUNCTION OF 

MINERAL TYPE 

In our haste to find answers to the more exotic problems of geochronology, ma:ny of the important details 

of •argon distribution and retention in v·arious minerals 

were not carefully investigated and are only slowly being supplied. Thus, the early rejection of all feldspars 

for potassium-argon analysis has been shown to have 

been too wide-ranging in scope. Virtually all volcanic 

feldspars seem to be satisfactory for potassium-argon 

dating throughout the Phanerozoic (Evernden and 

James, 1964). After the data were studied and this conclusion reached, it was not understandable why all feldspars of granitic rocks should be poor argon .traps. Inspection of thin sections, however, shows that extensive 

alteration of both potassium .. feldspar and plagioclase 

is virtually universal in the granitic rocks of the Sierra 

Nevada, and these minerals would be expected to· be 

sources of poor potassium-argon dates. It appeared. possible that use of altered or exsolved feldspars led to 

the early conclusions. Six relatively unaltered rocks 

were selected for complete analysis (table 3). 

All feldspar concentrates were leached in hydrofluoric acid (Evernden and Curtis, 1965), sonically cleaned, 

and resized. 

Four of the potassium-feldspar samples show either 

no microcline or only its incipient development, the 

potassi~m-argon ages of these samples being essentially 

concordant with the biotite ages on the same rocks 

(KA 1512, 1564, 1569, ·and 1605). Another potassiumargon age ·for untwinned potassium-feldspar from a 

Sierran granitic rock concordant with that for biotite 

and hornblende from the same specimen is reported in 

Kistler and Dodge (1966). The two potassium-feldspar samples which yielded ages in marked discordance 

with the biotite ages from the same· rocks ( KA 1533 

and 1541) are extensively or completely converted to 

microGline. 

The correlation of observed plagioclase characteristics with apparent age is not so obvious, but the six 

dates suggest the correlation of high argon retentivity 

with coarse to intermediate twinning thickness, and the 

correlation of low argon retentivity with alteration, 

thin twinning, and obvious strain. Since myrmekite is 

always a peripheral development, it may be that leaching with HF and sonic cleaning tend to remove such 

material from our concentrates, thus preventing the 

expected correlation of myrmekite development and deficient apparent ages. 

The sample used is small, but it strongly suggests that 

a correlation exists between demonstrable crystal characteristics and apparent potassium-argon ·ages in the 

feldspars of instrusive rocks, a to-be-expected but ·as 

yet unsubstantiated result. The basic requirement seems 

to be an unrecrystallized homogeneous crystal phase 

with dimensions of at least several microns, that is, exactly what the stu~y of argon retention in volcanic feldspars had indicated (Evernden and James, 1964). 

APPARENT POTASSIUM-ARGON AGES OF QUARTZ 

FROM GRANITIC ROCKS 

As first noted by Hart (1964), and as subsequently 

found by several investigators, it is possible to have 

excess quantities of argon in some pyroxenes of rocks of 

deep-seated origin. Exactly what "deep-seated" means 

in this connection is uncertain. Investigations of pyroxenes, sanidines, and plagioclases (oligoclase to bytownite) of extrusive volcanic rocks have found no argon 

excess. Where do granitic intrusive rocks lie in this 

proposed-hierarchy of depth; that is, will the low-potassium minerals of granitic rocks show an argon excess~ 

Analyzed pyroxenes of granite samples from the Sierra 

Nevada show the absence of excess argon (Kistler and 

Dodge, 1966). The sole remaining mineral present in 

appreciable quantity is quartz. The very low potassium 

content, its very late crystallization, and the possibility 

of gaseous inclusions within it would suggest that, if 

excess argon is to be found in granitic rocks, it will be 

found in quartz. Five quartz samples from Sierran 

granitic rocks have been analyzed. 

Analysis of fine quartz samples from Sierran granitic rocks 

Run Mineral K Apparent (percent) age (m.y.) 

KA 1512 ____________ Biotite _____________ 7. 429 96. 7 

1512-QTZ _______ Quartz_____________ . 0279 109. 4 

1533 ____________ Biotite _____________ 7. 545 82. 5 

1533-QTZ _______ Quartz_____________ . 0250 88. 9 

154L ___________ . Biotite _____________ 7. 705 94.2 

1541-QTZ _______ Quartz _____________ . 0188 108.3 

1564_ _ _ _ _ _ _ _ _ _ _ _ Biotite __________ ~_ 7. 528 88. 5 

1564-QTZ _____ ;.._ Quartz_____________ . 0144 57. 9 

'1569 ____________ Biotite------------- 7. 971 102. 3 

1569-QTZ _______ Quartz_----________ . 0401 58. 1 
8 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

The potassium values were obtained by flame-photometry ·analysis, the only technique immediately available, 

and it is felt that the values computed are adequate 

for investigating the presence of excess argon in these 

samples. 

Sample preparation was by crushing, sizing, and 

heavy liquids, followed by a very strong HF leach; the 

intent of this leaching was to destroy all plagioclase or 

·to so grossly alter it that it could be easily separated 

from the quartz by picking. The picked concentrate was 

again leached in HF and sonically cleaned. The quartz 

was fused in our standard argon-extraction lines according to the procedure outlined previously for use with 

very young samples ( Evernden and Curtis, 1965). Pyrex 

bottles with vicor liners were cooled by a strong stream 

of air. The residue was a somewhat vesicular mass in 

the bottom of the molybdenum crucible, approximately 

half of the quartz having been vaporized and thus reTAliLE 3-Multimineral analyses (of same rock) 

Run Mineral K Age 8(:-u) Remarks based upon examination of thin section of rock 

(percent) (m.y.) (percent) 

KA 1512 _________ Biotite_____________ 7. 429 96. 7 

1512-HBD ____ Hornblende_________ . 666 97. 8 

1512-PL ______ Plagioclase_________ . 297 92. 5 

1512-KF _____ Orthoclase __________ 11. 54 100.1 

KA 1533 _________ Biotite ____________ _ 

1533-HBD ____ Hornblende ________ _ 1533-PL ______ Plagioclase ________ _ 

7. 545 

. 670 

. 310 

1533-KF _____ Orthoclase __________ 11. 95 

KA 154L ________ Biotite ______ ---- __ _ 1541-HBD ____ Hornblende ________ _ 1541-PL ____ · __ Plagioclase ________ _ 

7. 705 

. 736 

. 233 

1541-KF _____ Orthoclase __________ 12.25 

KA 1564 _________ Biotite ____________ _ 

1564-HBD ____ Hornblende ______ ~ __ 1564-PL____ _ _ Plagioclase ________ _ 

7. 528 

1. 070 

. 277 

1564-KF _____ Orthoclase __________ 11.69 

KA 1569 _________ Biotite ____________ _ 

1569-HBD ____ Hornblende ________ _ 1569-PL ______ Plagioclase ________ _ 

7. 971 

. 590 

. 774 

1569-KF _____ Orthoclase __________ 9. 253 

KA 1605 _________ Biotite ____________ _ 

1605-HBD ___ ~ Hornblende ________ _ 1605-PL ______ Plagioclase ________ _ 

7. 531 

. 888 

. 254 

82.5 

84.3 

70.3 

73.5 

94. 4 

97.8 

90. 7 

83. 5 

88.5 

95.6 

72. 6 

87. 5 

i02. 3 

107. 5 

102.4 

100. 1 

87. 4 

90. 1 

88. 7 

KA 1512 

0. 4 Extensively chloritized (carefully picked concentrates used 

for analysis) . . 5 Extensively chloritized (carefully picked .concentrates used 

for analysis). 

. 1 Twinning thin and close. Alteration throughout grains. 

Virtually no myrmekite. Wavy extinction function of 

zoning. 

. 1 Incipient microcline and very low wavy extinction. 

KA 1533 

0. 4 Low chlorite. . 0 Low chlorite . 3. 0 Exceedingly fine twinning in some grains. Extensive alteration in coarse grains. Extensive myrmekite. 

. 5 Microcline. 

KA 1541 

0. 7 Very low chlorite. 

. 9 Very low chlorite . . 1 Much myrmekite. Pronounced wavy extinction. Coarse 

twinning. Zoned. Less altered than KA 1533-PL . . 5 Extensive microcline twinning. Pronounced wavy extinction. 

KA 1564 

0. 2 Very low chlorite. 

. 9 Very low chlorite. 

. 8 Strong zoning. Myrmekite present but thin. Minimal wavy 

extinction. En echelon shear in plagioclase grains. Some 

distortion evident . . 3 Essentially no microclinization. Minimum wavy extinction. 

KA 1569 

0. 1 Slight alteration. 

. 3 Slight alteration. 

2. 0 Big broad twins. Alteration locally strong internally and on boundaries, but not general. . 5 Very mild strain. K-feldspar growing around plagioclase. 

Feathery twins locally. 

KA 1605 

0. 2 Slight alteration. 

. 2 Slight alteration. 

. 6 Strongly zoned .. Alteration slight. Intermediate twinning 

1605-KF _____ Orthoclase __________ 11. 67 density. 87. 0 ________ Incipient microclinization. Moderate wavy extinction. 
GEOLOGIC INTERPRETATION 9 

moved from the crucible. There was no trouble with 

blowing-out of samples. 

The potassium values (high for quartz) are certainly 

not attributable to separate grains of feldspar. They 

may be due to feldspar inclusions in quartz, although 

none were noted in thin-section examination. The distinctly higher potassium value for KA 1569-QTZ may 

indicate lack of removal of all altered plagioclase from 

the final concentrate, although the sample ·appeared as 

thoroughly fused as the others. If the data of the first 

four runs are averaged, the mea.n biotite age is 90.5 m.y. 

and the mean quartz age is 91.1 m.y.; the average values 

for all five runs are 92.8 m.y. and 84.5 m.y., respectively. 

The lack of any excess argon is obvious. 

The environment of emplacement of the granitic 

rocks of the Sierra Nevada of California was such that 

no measurable excess argon was incorporated in any of 

the m-ajor minerals at time of formation, emplacement, 

or cooling of the plutons. Shallow emplacement, with 

correspondingly low confining pressure on gas content 

of residual fluids, is suggested by this result. Incidentally, we have found excess argon in the quartz of the 

Precambrian gneisses investigated by Hart (1964), in 

two samples of pegmatitic quartz, and in a quartz cobble 

from the Precambrian Witwatersrand conglomerates 

( un pub. data, U niv. California, Berkeley). Ram a, Hart, . 

and Roedder (1965) have reported excess argon 111 

samples of pegmatitic and vein vuggy quartz. 

G.EOLOGIC INTERPRETATION 

GENETIC SIGNIFICANCE OF POTASSIUM-ARGON AGES 

OF BIOTITE AND HORNBLENDE 

POTASSIUM-ARGON AGE IN PLUTONS OF 

CATHEDRAL PEAK TYPE 

We shall now be concerned solely with the ages obtained on biotites and on biotite-hornblende pairs. We 

shall assume that the patterns of ages observed have 

some genetic significance and shall attempt to understand the genesis of the pluton complex by a study of 

these ages. We shall also assume that the observed pattern of ages in these mineraJls is due to a complex intrusion and cooling history, that is, that argon diffusion and 

loss is largely a heat-dependent phenomenon. Also, we 

shall assume that we have largely avoided the problem 

of age being a function of potassium content in biotite 

by using carefully picked concentrates. As discussed 

in the first part of the report, we seem to have not completely escaped this problem in the Cathedral Peak pluton, but if this factor does not confuse the data any 

more than it does in that pluton, the major conclusions 

to be drawn from the entire body of data will be valid. 

There were two main reasons for selecting plutons of 

Cwthedral Peak type for detailed study. First, field relationships indicate they are virtually the youngest plutons of appreciable size in the Sierra Nevada. Reheating 

effects of later plutonism should be nonexistent, and 

the observed pattern of ages should refleot the pattern 

of emplacement and initia:l cooling. Secondly, plutons 

of this extremely distinctive rock type occur as a sequenoe of narrow elongate bodies along 160 miles of the 

Sierran crest (fig. 2, 3). The rock is a quartz monzonite 

typified by very large microcline phenocrysts. In several places, field mapping has not yet defined the limits 

of the plutons, such areas being indicated by question 

marks in the figures. All contacts with older rocks are 

essentially vertical wherever they have been clearly observed. These plutons must be considered, on the basis 

of field evidence, to be discrete bodies for considerable 

distances below the surface. 

Consider first the data of the Cathedral Peak pluton. 

An earlier discussion shqwed the correlation of apparent 

age and potassium content. It was there shown that 

determined ages of carefully picked high-potassium concentrates were not strongly affected by their small 

chlorite content. In the present discussion, the significant points are that in carefully picked high-potassium 

concentrates there does not seem to be any correlation 

of apparent age with elevation or with east-west position 

but that there is a definite correlation of age with northsouth position-the south end seems to be 2 to 3 m.y. 

older than the northern end. Since age does not seem 

to be a function of elevation in the pluton, an explanation of the north-south difference cannot be found in a 

hypothesis of pronounced tilting of the pluton. A difference due to depth of erosion is completely ruled out 

by field evidence. Also, if age is independent of depth, 

then emplacement was shallow (see below) and cooling 

subsequent to final emplacement was rapid; the explanation that ages are based upon the complex pattern of 

cooling of a pluton emplaced at all points at nearly the 

same time is improbable. The. only hypothesis that would 

seem to fit the facts is one that assumes shallow emplacement and a spread of 2 to 3 m.y. in the time of final 

emplacement of the two ends of the pluton, that is, a 

history that allows final cooling of the two ends of the 

pluton to have been separated by 2 to 3 m.y. 

The data from the Sonora pluton (fig. 2) suggest age 

to be a function of east-west position rather than northsouth or vertical positions. In the Recess pluton (fig. 3), 

the few data suggest no dependence of age on northsouth position, are suggestive of a correlation of age and 

elevation (1 m.y. per 2,000 ft), and unequivocally indicate this pluton to be younger than either of the more 

northerly plutons. The contrast in age between the 

southern end of the Cathedral Peak pluton and the 

northern end of the Recess pluton cannot be explained 

on the basis of tilt during uplift of the mountain range. 
10 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

30'~ 

15'~ 

1547 

1546 .85.6 

84.2 7400' 

7560' .. 

1542 

84.8 

7650' .. 

1538 • 83.3 (84.2) 

5520' 

45' 

T 

+ 

81 7 1548 . 81.1 • 81.7 

7450' 7500' 7600' 

30' 

81.9 

5200' 

)]

13Ts4 

Sonora pluton 

(Sinuosity of outcrop due to 

overlying volcanic rocks) 

+ 

+ 

Cathedral Peak 

pluton 

EXPLANATION 

/Run number 

1527 /Biotite age (hornblende age), 

81 9 . "II" f 

S I I l

·t 8 · 1n m1 1ons o years amp e oca 1 y-. 800'. . Elevation 

0 5 10 15 MILES 

1594 

82.4 

84.6 8700' 533 

• 8800' • 82.5 (84.3) 

• 8800' 

.1532 

83.2 

8800' 

_j 

FIGURE 2.-Potassium-argon dates on samples from plutons of Cathedral Peak type, Sonora and Cathedral 

Peak plutons. 
GEOLOGIC INTERPRETATION 

v 119°15' 

Cathedral Peak+ 

pluton 

B 

+ 

EXPLANATION 

119°00' 

+ 

+ 

1589 ~ . 79.6 .. 

11,500'. . . 

1587 1584 

78.4 1588 79.1 (80.0). 

9280' 81.8 8480' .1592 • 11,530' 80.1 (81.5) /Run number 

1587/Biotite age (hornblende age), 

7680' 

78.4 in millions of years 

Sample locality-. 9280'-Eievation 

1590. 1591 

81 7 79.3 

13:777' 11,600' 

0 5 10 15 MILES 

+ 30' 

Whitney pluton 

+ 

1586 

80.5 

9680' 

A 

Lagille Peak 

plut~ 

FIGURE 3.-Potassium-a·rgon dates on samples from plutons of CaJthedral Peak type. A, Recess pluton; B, 

Whitney pluton. 

11 
12 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITIDC COMPLEXES IN CALIFORNIA AND NEVADA 

The data from the Lagille Peak pluton (fig. 3) are too 

limited to warrant detailed analysis. 

The pattern of ages in the Whitney pluton is not well 

placed for a study of the relation between age and 

potassium content, since the samples were selected to 

investigate age as a function of position. Only subsequent to sample collection did the results from the 

Cathedral Peak pluton become available. 

If the absolute age data obtained in the Whitney 

pluton are interpreted in terms of dipping isochronal 

surfaces, a correlation between east-west position, elevation, and age appears-the isochrons dipping about 7° 

westward and having a perpendicular separation of 

about 600 feet for a time difference of 1 m.y. This conclusion is based upon a somewhat arbitrary analysis of 

the data, but it is interesting that this part of the Sierra 

is thought to have had much greater uplift and associated erosion than the area to the north (the general 

absence of roof pendants being considered significant). 

If relative uplift and erosion have been measured in 

thousands of feet, the appearance southward of age as a 

function of elevation is not surprising. It is concluded 

that there is no linear trend in the order of emplacement of the Cathedral Peaktype plutons but that there 

is an increasing dependence of age upon elevation southward (for Cathedral Peak pluton, no observable change 

in age for 4,000 ft; Recess pluton, 1 m.y. per 2,000 ft.; 

Whitney pluton, 1 m.y. per 600ft). 

Three biotite-hornblende pairs support the conclusion 

that several millions of years were involved in the emplacement of these quartz monzonite plutons : KA 1533 

(82.5 m.y.) and KA 1533-HBD (84.3 m.y.) from the 

Cathedral Peak pluton; KA 1553 (78.8 m.y.) and KA 

1553-HBD (77.4 m.y.) from the Recess pluton; and KA 

1584 (79.1 m.y.) and KA 1584-HBD (80.0 m.y.) from 

the Whitney pluton. The internal agreement of each 

pair implies real significance for the age indicated by 

each pair, and the spread of mean ages of the three pairs 

implies real differences in the age of each pluton. 

DEPTH OF EMPLACEMENT OF THE 

SIERRAN PLUTONS 

The data we shall use to determine the depth of empla·cement of the Sierran plutons are the data on the 

rel-ation of age to elevation in the Cathedral Peak-type 

plutons. Such an approach to evaluating depth of emplacement must be based upon a heat model of granite 

emplacement and cooling. We are at once upon uncertain 

ground. But if the tenuousness of the fabric 'being woven 

is fully appreciated, no harm results from such discussions, and possibly some useful ideas may result. 

The required parameters of the problem are several. 

First, one must assume the existence and value of a 

steady-state temperature gradient. This can be generated either by radioactivity within the upper 25 km of 

the crust or by a heat source below the upper layers. As it 

will not make any particular difference in the results, the 

latter model is chosen because of its ease of handling. 

A maximum of 33°C per km and a minimum of 25°C per 

km are suggested by heat flow and borehole data as 

limitS of permissible gradients. For reasons discussed 

below, the gradient is achieved by holding the temperature constant at 800°C at the appropriate depth. If we 

consider that the data previously obtained on argon 

diffusion in phlogopite and glauconite by Evernden, 

Curtis, Kistler, and Obradovich (1960) are relevant to 

biotite under a load of several kilometers, some conclusions are immediately possible. First of all, note that one 

of the figures given in this earlier work is not correct. 

As pointed out by Paul Damon, the appropriate time 

interval to go with the listed I values is 106

. years rather 

than 105 years. Therefo·re, an I value of 0.4 is to be associated with 325°C for biotite grains with a significant 

diffusion dimension of 1 millimeter. Since the significant 

diffusion dimension for biotite grains of Sierran rocks 

is probably less than 1 millimeter, 325°C is certainly 

beyond the temperature range at which rocks of nearly 

the same age could remain for 2 to 3 m.y. and still display differences in age on the order of a few million 

years. With a surface temperature of 30°C, the 300°C 

isotherm of the model is pertinent. Factors inconsistent 

with emplacement of these plutons at depths where the 

ambient temperature is 325°C are the biotite age differential between the southern end of the Cathedral Peak 

pluton and the north end of the Recess pluton; the concordance of the biotite-hornblende pair from KA 1533 

(Cathedral Peak pluton); and the lack of any dependence of age upon el~vation in the Cathedral Peak pluton. 

The levels now exposed of these pluton ends were certainly at the same depth at all times since emplacement 

of the younger. If they were ever both at 325°C at the 

same time, they would certai~y show essentially identical ages today, would probably display discordant 

biotite-hornblende ages, would display age as a function 

of elevation, and the two ends of the Cathedral Peak 

pluton ~ould not show different -apparent ages. Thus, on 

the argument of geothermal gradient alone, the maximum permissible depth for the top of the plutons is less 

than 12 km for 25 ° C per km, or 9 km for a gradient of 

33"C per km. 

What is the temperature of a pluton at the time of 

"initiation of cooling"~ We shall not attempt to discuss 

the period of time involved in emplacement of a pluton 

or the temperature history during that ti·me. We presume that ·we can establish a tmnperature distribution of 

approximately the correct type for the period when 
GEOLOGIC INTERPRETATION 13 

cooling became the ruling heat process. The model will 

be designed to err on the side of a low estimate of heat 

in the pluton after "initation of cooling" so that the · 

estimate· of depth of emplacement will be a maximum. 

The geologic thermometer used to establish the ternperature at time of "initiation of cooling" is the mineral 

assemblage found in roof pendants, zenoliths, and metamorphic aureoles of the plutons. Bateman, Clark, 

Huber, Moore, and Rinehart ( 1963) can be consulted for 

a discussion of these metamorphic rocks and their mineral assemblages. The essential feature is that they are 

predominantly hornblende hornfels with a small percentage of pyroxene hornfels, and locally display both 

wollastonite- and calcite quartz-bearing phases as well 

as andalusite- and sillim'8Jlite-bearing phases. Therefore, the mean temperature condition during the genesis 

of these rocks was in the pressure-temperature region 

where the three phase boundaries of figure 4 intersect. 

The andalusite-sillimanite data (Weill, 1966) are essential to the argument. The calcite quartz-wollastonite 

data are from Ellis and Fyfe ( 1956) and the pyroxene 

hornfels-hornblende hornfels curve is from Fyfe, 

Turner, and Verhoogen (1958). The PH-HH curve is 

hypothetical and can move appreciably in response to 

varying total composition of the rock, but it is thought 

to be at very nearly the correct position for rocks of 

granitic composition. The conclusion is that a temperature of approximately 600°C is predicted for rocks 

forming near these phase-boundary intersections. Since 

such a temperature implies that the granitic mass was 

largely crystalline at this time, heat of crystallization 

can be disregarded. 

The heat model at time of "initiation of cooling" is 

then 800°C (800°C is ·adequ•ate, as this is well above 

600°C) held constant at the appropriate depth, geothermal gradient to 600°C, 600°C to depth D below the 

surface, ·and a uniform gradient to the surface (fig. 5A) . 

No ·account is taken of lateral cooling, for the Cathedral 

Peak pluton and the surrounding portions of the Half 

Dome pluton show no l·ateral variations in age. The ages 

in the Half Dome pluton near the contact with theCathedral Peak pluton are indistinguishable from those 

of the Cathedral Peak pluton, •and the dates within the 

latter are uniform from edge to edge. The final step 

is to cool this mass to the geothermal gradient by conduction without introduction of additional he:at. As can 

be seen, every theoretical departure from the actual 

environment is probably in the direction of underestimating heat available. The computations were carried 

through for several values of D (depth of emplacement). Figure 5B shows the position of the 300°0 

isotherm as a function of D, depth of emplacement; d, 

depth into the pluton; and t, time in 10 6 years since 

initiation of cooling. 

859-885 0~9----.8 

(/) 

0:: 

<( 

m 

0 

...J 

~ 

z 

"N 

0 

rf:1 

-

0:: 

e. 

c 

z 

<( 

0 

N 

a: 

4 

2 

TEMPERATURE, IN DEGREES CENTIGRADE 

EXPLANATION 

Kyanite-silllmantte-andalusite (K-5-AI curves. 

Curves from Weill (1966) are designated 

(WI; curve from Holm and Kleppa (1966) is 

designated (H and K). 

Wollastonite-calcite/quartz (W-c/01 curve from 

Ellis and Fyfe (1956). 

Pyroxene hornfels-hornblende hornfels (PH-HHI 

curve from Fyfe, Turner, and Verhoogen (1958). 

FIGURE 4.-Pressure-teiQperature fields for metamorphic 

mineral and rock p·airs. 

We will use the 300°C of our model as our guide 

temperature for the reasons stated. We will also assume 

that the pattern of movement of this isotherm in the 

cooling pluton is reflected quite closely in the pattern of 

age in relation to elevation in the pluton today. In the 

discussion which follows, figures not in parentheses refer to a 33 o C per km gradient; figures in parentheses 

refer to a 25°C per km gradient. Note first the data for 

D=8(11) km. At the top of the pluton, the 300°0 isotherm subsides 0.7 km in 10 6 years ( 0.7 km in 1.8 X 10 6 

years). At greater depth · (the tops of all the plutons are 

now eroded), this isotherm subsides more slowly. Assuming the validity of the assumption made above, it 

can be stated that ·a pluton emplaced at 8(11) km depth 

must show age as a function of elevation at least to the 

level 10 6 years within 2,000 feet ( 1.8 X 10 6 years within 

2,000 feet). Such is not observed in the Cathedral Peak 

pluton and so such values of D are inadmissible. 

For D=4 (5.5) km, age as a function of elevation at 

the top of the pluton is predicted to be 0.6 X 106 years 

within 1.8 km (1.1X 106 "years within 1.8 km), while 

at 2.5 km depth within the pluton (d=2.5) 

a rate of 106 years within 1.4 km ( 1.8 X 106 
14 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Li.J 

Cl 

ex: 

a:: 800 

(.!) 

t= 700 z 

Li.J 

(.) 600 (/) 

Li.J 

Li.J 

a:: 500 

(.!) 

Li.J 400 Cl 

~ 300 

LJ..i 

a:: 

:J 200 1-

ex: 

a:: 100 Li.J 

a.. 

~ 

Li.J 

1-

(-6) (-4) 

-4 -2 

4 

D 

It =0.0125 cgs 

8 12 16 

DEPTH, IN ·KILOMETERS 

A 

B 

20 24 

9 

FIGURE 5.-Heat model for intrusive rocks of the Sierra Nevada. Numbers in parentheses refer to a 25°0 per km geothermal gradient. Numbers not in parentheses refer to a 

313 o C per km geothermal gradient. A. Assumed temperature 

distribution at "initiation of cooling" and geothermal 

gradient. B. Position of 300°0 isotherm as function of d 

(depth into pluton), D (depth of emplacement), and t (time 

in 108 years since "initiation· of cooling"). 

years within 1.4 km) is predicted. Whether a D of 4 

km is admissible depends upon the depth of erosion of 

the pluton today. In any case, a .D of 6 km is inadmissible on this model. Note that the suggested gradients in 

the Recess and Whitney pl~tons can be found on the 

profile for D = 5 km or less at values of d of a very few 

kilometers. Thus, the entire pattern of observed gradients can be explained by intrusion to depths of 5 km or 

less and subsequent pronounced tilting of the batholith. 

Such tilting has often been invoked to explain the lack 

of roof pendants in the Mount Whitney area. 

Is this prediction of shallow emplacement supported 

or denied by other data? Broad-scale field investigations tend to support such shallow depths of emplacement because of the demonstrably short interval of 

geologic time between emplacement and unroofing by 

erosion of such plutons and because of the known thickness of sediments which accumulated as a result of 

erosion between the time of emplacement and exposure 

of the plutons (Curtis and others, 1958). Bateman, 

Clark, Huber, Moore, and Rinehart (1963) have argued 

for a depth of emplacement of Sierran plutons of 15 km, 

basing their arguments on the mineralogy of the metamorphic and igneous rocks. As regards the metamorphic 

rocks, the present uncertainties in position of the plotted 

sillimanite-kyanite-andalusite triple point make impossible any detailed conclusions on temperature and 

depth of emplacement of these plutons based upon position of this triple point. Reference should be made to 

the article by Holm and Kleppa (1966) in which the 

various computed positions of the sillimanite-kyaniteandalusite phase boundaries are plotted. The phase 

bonndaries as plotted by Weill (1966) agree nicely with 

our heat-flow analysis. The essential point for our 

analysis is the intersection of the sillimanite-andalusite 

and the wollastonite-calcite/quartz curves. Based on 

Weill's data, a temperature of approximately 600°C 

and a Pu2o=P co2 of 0.8 kilo bars are predicted as the 

temperature-pressure conditions for genesis of the observed metamorphic mineral assemblages in the Sierra 

Nevada. If Pu2o is presumed to be equal to Ptoad' a 

depth of emplacement of 3 km is predicted, whereas if 

Pu20 is hydrostatic, a depth of 8 km is predicted. There .. 

fore, there is no conflict with the depths predicted by 

the heat-flow model. The data of Holm and Kleppa, together with the wollastonite-calcite/quartz data of Ellis 

and Fyfe (1956), predict that the temperature .. pressure 

conditions necessary for genesis of these rocks are 700°C 

and 3 kb. At present, we see no obvious way to decide on 

the relative merits of the investigations of Weill (1966) 

and Holm and Kleppa (1966). The conclusion must be 

that the mineralogical data predict temperatures be .. 

tween 600°C and 700°C and pressures of 0.8 to 3.0 kb 

with no more refined specification possible. Bateman's 

argument based upon the composition of the granitic 

rocks has two flaws well known to him. First, it was 

necessary to argue about the anorthite-albite-orthoclase 

system while possessing only data on the albite-ortho .. 

clase system. For this reason, one cannot evaluate the 

soundness of his argument as applied to granites of the 

SierraN evada area. Secondly, much crystallization may 

well have taken place prior to final emplacement of the 

pluton. Therefore, we can state that neither of Bateman's thermometers is sufficiently well calibrated to 

allow prediction of depth of emplacement of the Sierran 

plutons. There is no clear demonstrable disagreement of 

the mineralogical data with our conclusions. 
GEOLOGIC INTERPRETATION 15 

DISCORDANT BIOTITE-HORNBLENDE PAIRS--

EVIDENCE OF REHEATED PLUTONS 

The gross discordances in potassium-argon ages of 

biotite-hornblende pairs from specimens of granitic rock 

found by Kistler, Bateman, and Brannock (1965) on 

the east side of the Sierra Nevada and further data in 

this report are clear evidence that old granitic rocks 

(180-210 m.y.) were reheated by much younger plutons 

(90-80 m.y. old). 

The numerous discordant samples reported by Kistler, 

Bateman, and Brannock ( 1965) are shown on plate 2. 

The samples that displayed marked discordance 

(greater than 5 m.y.) in the present study are given in 

the following table. 

Samples in present study that show discordance greater than 5 m.y. 

Age (x-u) Run Mineral (m.y.) (per- Remarks 

cent) 

KA 1432 __ ---- Biotite _______ 128 0. 6 West of ''Upper 

Cretaceous'' 

1432 ___ ---- Hornblende ___ 142 plutons. 

.4 Do. 151L ______ Biotite _______ 97 . 1 Do. 

1511-HBD_ Hornblende ___ 125 .7 Do .. 1519 _______ Biotite _______ 92 .3 

1519-HBD_ Hornblende ___ 100 .7 1540 _______ Biotite _______ 89 .0 

1540-HBD_ Hornblende ___ 97 .6 1564 _______ Biotite _______ 89 .2 Marked discord- ance in all 

minerals from 

this rock. 

1564-HBD_ Hornblende ___ 96 . 9 Do . 1582 _______ Biotite _______ 74 . 9 Walker Pass . 1582-HBD_ Hornblende ___ 86 . 5 Do . 1601 _______ Biotite _______ 83 .5 Lamarck Granodiorite, reheated 

bh Recess 

1601-HBD_ Hornblende ___ p uton. 

88 .8 Do. 1609 _______ Biotite _______ 87 .3 Discordance due 

to depth of 

emplacement 

1609-HBD_ Hornblende ___ and (or) erosion? 

93 . 1 

1626-----'-- Biotite _______ 94 .5 

1626-HBD_ Hornblende ___ 101 .6 1628 ____ --- Biotite _______ 104 .4 West of "Upper Cretaceous" 

1628-HBD_ Hornblende ___ plutons. 144 .2 1632 _______ Biotite _______ 152 . 1 

1632-HBD_ Hornblende ___ 162 . 1 1633 _______ Biotite _______ 89 .0 

1633-HBD_ Hornblende ___ 120 2. 0 1634 _______ Biotite _______ 144 .3 

1634-HBD_ Hornblende ___ 156 .9 1635 _______ Biotite_______ '125 . 1 

1635-HBD_ Hornblende ___ 148 . 1 1680 _______ Biotite _______ 61 .6 Southern 

California. 

1680-HBD_ Hornblende ___ 72 .7 1698 _______ Biotite _______ 108 . 1 West of "Lower 

Cretaceous" 

1698-HBD_ Hornblende..: __ plutons. 140 .7 1699 _______ Biotite _______ 117 .0 

1699-HBD_ Hornblende ___ 140 .4 

Samples in present study that show discordance greater than 5 m.y. 

-Continued 

Run Mineral Age (x-u) (m.y.) (percent) 

Remarks 

DKA 1029 _____ Biotite_______ 85 _____ East of "Upper 

Cretaceous'' 

plutons. MKA 409 ______ Hornblende___ 95 ____ _ DKA 103L ____ Biotite_______ 83 ____ _ 1032 _____ Hornblende___ 93 ____ _ 1030 _____ Biotite_______ 99 _____ East of "Upper 

Cretaceous" 

MKA 410 ______ Hornblende __ _ KA 487----- ___ Biotite ______ _ MKA 458 _____ Hornblende __ _ 61019 _________ Biotite ______ _ 61025 _________ Hornblende __ _ 71022 _________ Biotite_-----_ 

61196 ___ ------ Hornblende __ _ 

206 ----- 88 ----- 97 ----- 149 ----- 158 ----- 86 ----- 101 

plutons. 

71083_ _ _ _ _ _ _ _ _ Biotite ______ _ 91 San Marcos 

Gabbro. 71067 _________ Hornblende ___ 101 

The argument of this section and the following ones 

will depend strongly upon the data of Hart (1964). 

Hart demonstrated the concordance of biotite and hornblende ages can indicate either initial cooling or degassing of both minerals by a later event. Concordance does 

imply a heating-cooling event, however. The pattern of 

discordance displayed by Hart's data is extremely important. The biotite, along the profile sampled by Hart, 

lost all of its argon before the hornblende indicated 

other than the uncertain indication of a 15 percent loss 

at great distance. Thus the pattern of discordance expected along a profile of reheating in the older mass win 

not be one showing near-concordance of biotite and 

hornblende at all distances, the age changing gradually 

from older to younger, but rather concordance beyond 

the effect of the younger pluton, with increasing discordance until the biotite reaches the age of the younger 

pluton, and only there, or farther on toward the younger 

intrusive, the decrease of hornblende ages to concordance with the biotite age. A series of ages such as ·that 

at "A" on plate 2 is the expected res1,1lt of reheating by a 

single 'later event. In that area, the older rocks are to 

the west, the younger to the east. The sequence of determined ages from west to east, that is, towards the 

younger intrusive is: 

Age (m.v.) 

Run Biotite 

KA 1700--------------------------------------

1699-------------------J-------- 117 

1698____________________________ 108 

1683____________________________ 102 

Hornblende 

138 

140 

140 

100 

Field evidence and lithology of sa:mple KA 1683 suggest that it is from the older granites (more acidic than 

rocks to east, evidence of extensive recrystallization, deu-
16 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

teric alteration of most minerals, and strong distortion 

of biotites). Reheating with consequent argon loss is 

clearly shown in the series at "B" on plate 2 and by 

numerous other samples on the western side of the 

Sierra. 

CONCORDANT BIOTITE-HORNBLENDE PAIRSEVIDENCE OF THE AGE OF AN INTRUSIVE EVENT 

We shall classify as concordant those pairs of ages 

which agree to within 5 m.y., such a degree of concordance being interpreted to mean that the pair of ages 

quite dosely date an intrusive event, either that of the 

rock dated or that of an adjacent intrusive. In order of 

determined age, the concordant pairs are as follows: 

Age (m.g.) 

Run 

]{A 1553---------------------------- 1584 ___________________________ _ 1667 ___________________________ _ 61001,61020 ________________________ _ 

]{A 1592---------------------------- 1533 ___________________________ _ 1538 ___________________________ _ 

9*----------------------------------

]{A 1508---------------------------- 71077, 71065 ________________________ _ 

21*---------------------------------

14*---------------------------------

]{A 13*--------------------------------- 1575 ___________________________ _ 1610 ___________________________ _ 488,61192 ______________________ _ 1605 ___________________________ _ 1539 ___________________________ _ 1516 ___________________________ _ 1514 ___________________________ _ 

FI> 13t------------------------------

6*---------------------------------- ]{A 1568 ___________________________ _ 

61007,61018 1678---------------------------- ________________________ _ 

]{A 71079, 1541---------------------------- 71073 ________________________ _ 

71075, ]{A 1512---------------------------- 71061 ________________________ _ 

]{A 71081, 1570---------------------------- 71071 ________________________ _ ]{A 1683 ___________________________ _ 

1629---------------------------- 1509 ___________________________ _ 1506 ___________________________ _ 1569 ___________________________ _ 1630 ___________________________ _ 1502 ___________________________ _ 

1438, 1439 ___ -------------------- 1440, 1441 ______________________ _ 

1436, 1624 ___________________________ 1437-----------------------_ 1701 ___________________________ _ 1664 ___________________________ _ 1702 ___________________________ _ 

61008, 61026_------------------------

Biotite 

79 

79 

80 

80 

82 

83 

83 

83 

88 

86 

87 

85 

87 

86 

88 

88 

87 

90 

87 

88 

90 

92 

92 

93 

94 

95 

94 

97 

94 

98 

98 

101 

103 

105 

101 

102 

114 

121 

126 

129 

132 

138 

143 

145 

153 

210 

•sample numbers from Kistler, Bateman, and Brannock (1965). tSentinel granodiorite from Kistler and Dodge (1966). 

Hornblende 

77 

80 

81 

83 

83 

84 

84 

88 

84 

88 

84 

87 

86 

88 

86 

86 

90 

89 

90 

91 

90 

91 

96 

98 

90 

98 

95 

98 

95 

102 

102 

100 

105 

105 

106 

108 

115 

121 

131 

132 

136 

136 

146 

148 

150 

206 

The greater number of .ages within the range 80 to 108 

m.y. is largely the result of the sampling pattern and 

is not to be considered significant in interpretation. 

RaJther, the distribution of rocks according to age groups 

as shown on plate 1 is a more ·accurate estimate of the 

relative significance of each age interval in the genesis 

of the batholith. These d81ta show that no concordant 

pair of ages is 181Cking for any significant time interv-al 

after ·an age of 150 m.y. Certainly, there are two periods 

. of 10 million years for which there are no ·ages, but the 

chances seem good that those intervals could be filled 

by selective sampling. The concept of several distinct 

periods of granite em pl81Cement separated by long intervals of no granite emplacement (Curtis and others, 

1958; Kistler and others, 1965) is not supported by the 

total body of potassium-argon ages. A more reasonable 

interpretation of the mineral age data is that granite 

emplacement in the environs of the Sierra Nevada was 

an essentially continuous process covering the period 

from 210 m.y. ago up to approximately 80 m.y. ago. As 

will be discussed below, the volume of granite emplaced 

in equal intervals of time was probably grossly different 

and the pulses of orogeny that geologists have defined in 

this area seem to be culmin81tions of activity of a basically continuous process. 

Therefore, the two areas of granitic terrane-eastern 

Australia and .the Sierra Nevada-in which ages have 

been reasonably well studied on a broad scale yield the 

same answer. Granite genesis and emplacement can be a 

nearly continuous process for more than 100 m.y. It will 

ba shown below, however, that the continuity of emp181Cement of plutons in the Sierra Nevada is actually 

the result of a series of pulses of granite genesis and 

emplacement which yield a continuous series of ages 

because of complex mechanical and thermal histories. 

The spacing of the pulses and the time required for the 

completion of each give the continuity of concordant 

potassium-argon ages. 

GROWTH OF THE SIERRA NEVADA BATHOLITH 

We here consider the pattern of ·ages obtained by all 

techniques throughout the Sierra Nevada and its en virons in order to clarify the preceding discussions of 

continuity in magmatic activity during the Mesozoic 

Era. The total body of data available, including ages 

obtained by potassium-argon, rubidium-strontium, and 

lead-alpha methods indicates that five major epochs of 

intrusion by granitic magma occurred from the Middle 

Triassic to the Late Cretaceous at intervals of approxim81tely 30 million years. We identify each epoch by 

numerical age representing the oldest known age correlated with that epoch; they are in the sequence 210, 180, 

148, 121, and 90 m.y. Distinctly mappable granitic rock 

series that were emplaced during each of these intrusive 

epochs have been well defined in California by comprehensive work in different areas by several field geologists 

(Calkins, 1930; Bateman and others, 1963; Kistler, 

1966b) . We shall first discuss the distribution of ages 
GEOLOGIC INTERPRETATION 17 

shown by all methods in these well-known areas (see 

outlined area, pl. 1) and then extmpol'31te to other areas 

on the basis of our potassium-argon data on biotite and 

hornblende. 

CATHEDRAL RANGE INTRlJSIVE EPOCH OF LATE 

CRETACEOlJS AGE 

The Cathedral R-ange intrusive epoch is here defined 

as the time of emplacement of granitic rocks of the 

Tuolumne Intrusive Series. This is the younger of two 

series of granitic rock in the Yosemite region of the 

Sierra Nevada that were defined by Calkins (1930). The 

younger series includes the Sentinel Granodiorite, 

Half Dome Quartz Monzonite, Cathedral Peak Granite 

and Johnson Granite porphyry. Subsequent mapping 

by other investigators has shown that rooks of the Tuolumne Intrusive Series occur along the crestal regions 

of the Sierra Nevad-a for its entire length (Mayo, 1941; 

Bateman, 1961; Broderson, 1962) and that these rocks 

represent the youngest intrusions in the batholithic 

complex. Dates for rocks of the Tuolumne Intrusive 

Series have been obtained by the potassium-argon method using mineral separates (Curtis 'and others, 1958; 

J(istler and others, 1965; Kistler and Dodge, 1966; and 

many more determinations in this report), by rubidiumstrontium isotope analyses of whole rocks (Hurley and 

others, 1965) and by the lead-alpha method ( J a:ffe and 

others, 1959; Bateman and others, 1963). The maximum age for the oldest member of the series, the Sentinel Granodiorite, by concordant potassium-argon 

d-ates on hornblende, biotite, and orthoclase from the 

same specimen of rock, is 90 m.y. (Kistler and Dodge, 

1966) . The lead -alpha age of uranothorite from the 

Half Dome Quartz Monzonite, .the next younger member of the series, is 88 m.y. ( J a:ffe and others, 1959) ; 

ages on zircons from the Lamarck and Round Valley 

Peak Granodiorites are 91 and 88 m.y., respectively 

(Bateman and others, 1963). According to Hurley, 

Bateman, Fairbairn, and Pinson ( 1965), a rubidiumstrontium whole-rock isochron of 90 m.y. can be constructed with the analyzed specimens of the Mount Givens and Lam-arck Granodiorites and later quartz monzonites from this series. All of the ·age data together indicate that the first increment of magma of the Tuolumne 

Intrusive Series was intruded 90 m.y. ago. The spread 

of concordant mineral ages from 90 m.y. to 79 m.y. is 

the maximum interval of time available for the intrusion of the tremendous volume of magma represented by 

these rocks and for the cooling of this mass to a temperature low enough to permit equal retention of radiogenic argon in biotite and hornblende (about 300°C, see 

page 12). Some of the spread in ages is due to the mechanisms discussed in other sections of this paper, but 

ages of mineral pairs from rocks emplaced during the 

Cathedral Range intrusive epoch are general.ly concordant and date the event as Late Cretaceous. 

HlJNTINGTON LAKE INTRlJSIVE EPOCH OF EARLY 

CRETACEOlJS AGE 

The Huntington Lake intrusive epoch is here defined 

as the time of emplacement of the granitic rocks represented by the granodiorite of "Dinkey Creek" type in 

the Huntington Lake area, Fresno County, Calif. and 

correlative intrusive rocks elsewhere. The granodiorite 

of "Dinkey Creek" type m·a.pped by Krauskopf ( 1953), 

Macdonald ( 1941), and Hamilton ( 1956) without delineation of individual plutons is ·a series of rocks ranging in composition from quartz diorite to quartz monzo. 

nite. The granodiorite of "Dinkey Creek" type in the 

vicinity of Huntington Lake is known from contact relationships to be older than the Mount Givens Granodiorite (Bateman and. others, 1963). In the area where 

the "Dinkey Creek" type has been mapped, the maximum potassium-argon age of hornblende, determined 

from a quartz diorite at its westernmost exposure, is 

115 m.y., and the biotite-hornblende pairs from dated 

specimens generally have discordant ages (Kistler and 

others, 1965). Ages approach concordance (KA 1630) 

and a maximum only in specimens collected far from 

the contact between the granodiorite of "Dinkey Creek" 

type ·and rocks of the Tuolumne Intrusive Series to the 

east. A whole-rock rubidium-strontium isochron for a 

granodiorite of "Dinkey Creek" type exposed near 

Huntington Lake yields an age of 104 m.y. (fig. 6.A.; 

table 4). 

Other granitic rocks intruded during the Huntington 

Lake intrusive epoch include some of the plutons in the 

southern California batholith and those in the Santa 

Lucia Mountains of the so-called Coast Range batholith. The rubidium-strontium whole-rock age for the 

Santa Lucia plutons is 117 m.y. (fig. 6B; table 4). Banks 

and Silver (1966) report isotopic uranium-lead ages 

between 109 and 116 m.y. for zircons from plutons in 

the southern California batholith. All the geochronologic data show that the Huntington Lake intrusive 

epoch spans the time interval 121 m.y. to 104 m.y. ago 

and is Early Cretaceous in age. 

YOSEMITE INTRUSIVE EPOCH OF LATE JURASSIC AGE 

The Yosemite intrusive epoch is here named for the 

time of emplacement of granitic rocks exposed in 

Yosemite Valley-its type area .. These rocks include the 

biotite granite of Arch Rock, granodiorite of The Gateway, El Capitan Granite, and Taft Granite. It includes 

the so-called biotite granite series of the Yosemite 

Valley, which Calkins (1930, p. 121) dated as older 
18 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

0.720 {Sr87/Sr86)i =0.7057 

0.715 

~ en 

-;::.... 0.710 

"L 

en 

0.705 

0.715 

~ 

~ 0.710 

li 

en 

0.705 

(SrB7fSrB6) i =0. 7047 

2 3 

c 

4 

0.715 

t 0.710 en 

~ en 0.705 

0.700 

0.725 

0.720 

~ 0.715 en 

........ 

li 

en 0.710 

0.705 

0.700 

(SrB7fSr86) i =0. 7082 

\'2.\'(\·'J. 1-\- t~ \. \. ..- SL-298 

SL-31A 

SL-30 

0 1 2 3 

Rb87 /SrB6 

B 

(SrB7fSr86) i =0. 7065 . 

0 1 2 3 4 5 6 7 

Rb87 /Sr86 

D 

FIGURE 6.-Rubidium-strontium iSIOehron plots for granitic rocks in California. A. Granodiorite of "Dinkey Oreek" type. 

B. Plutons of Santa Lucia Mountains. C. Granitic rocks of the Yosemite intrusive epoch. D. Quartz monzonite of Lee 

Vining Canyon. (Analytical uncertainty does not include the uncertainty in the Rb87 decay constant.) 

than his Tuolumne Intrusive Series because the Sentinel 

Granodiorite of the Tuolutnne intrudes the El Capitan 

Granite. 

Age determinations of rocks intruded . during the 

Yosemite intrusive epoch have been obtained by 

potassium-argon analyses of biotite and hornblende 

(Curtis and others, 1958, and this report) and by 

rubidium-strontium isotopic analyses of whole rocks. 

The maximum mineral age (101 m.y.) for this series in 

the type area is for hornblende from a specimen collected at the most westerly outcrop of granodiorite of 

The Gateway (KA 1663), but rubidium-strontium analyses of whole-rock specimens of biotite granite of Arch 

Rock, El Capitan Granite, and Taft Granite yield an 

isochron of 136 m.y. (fig. 60; table 4). The data suggest 

that the mineral ages from specimens in the Yosemite 

Valley area have all been reduced by various amounts 

by reheating during the later intrusions of the Tuolumne Intrusive Series to the east and the granodiorite 

of "Dinkey Creek" type to the south. The rubidiumstronti urn age indicates the biotite-granite series of the 

Yosemite Valley to be a temporal equivalent of the Late 

Jurassic granitic rocks of the foothill belt to the west. 

The foothill granitic rocks generally have concordant 

biotite-hornblende potassium-argon ages between 148 

and 136 m.y. (KA 1624), etc. All the geochronologic 

data show that the Yosemite intrusive epoch spans the 

time interval 148 to 132 m.y. ago and is Late Jurassic 

in age. 

INYO :MOUNIXAINS INTRUSIVE EPOCH OF EARLY AND 

MIDDLE JURASSIC AGE 

The name In yo Mountains intrusive epoch is here 

assigned to the period of time when the majority of the 

plutonic rocks exposed in the Inyo and White Mountains and the Tinemaha Granodiorite and granodiorite 

of McMurray Meadows exposed in the Sierra Nevada 

were emplaced (Bateman, 1961; McKee and Nash, 

1967). The Lamarck Granodiorite intruded during the 

Cathedral Range intrusive epoch is known from contact 

relationships to be younger than the Tinemaha Granodiorite in the area of exposures near the crestal region 

of the Sierra Nevada southwest of Big Pine, Calif. 

(Bateman, 1961). 

Age determinations of rocks intruded during this 

epoch are from potassium-argon analyses of biotite and 

hornblende (Kistler and others, 1965; McKee and Nash, 

1967; this report) and from lead-alpha ages of zircons 
GEOLOGIC INTERPRETATION 19 

TABLE 4.-Rubidium-strontium analytical data 

[BIUlta Lucia Mountains SIUllples Malyzod by R. W. Kistler; all other analyses by Carl E. Hedge] 

Sample Rb Sr(total) (ppm) (ppm) 

LEE VINING INTRUSIVE EPOCH 

1-340 ___ Quartz monzo- 160 

nite of Lee 

Vining Canyon. 357 ________ do_________ 156 

337 ________ do_________ 185 

140 

85.8 

86. 3 

YOSEMITE INTRUSIVE EPOCH 

Ar-3 ____ Biotite granite 

of Arch Rock. 

1 80.,6 1 448 

EC-B ________ do _________ 1 84.6 1 313 5 ___ El Capitan 1 127 1 240 

Granite. 6 ________ do _________ 1 127 1 223 

T-8----- Taft Granite ____ 1 148 1 197 

3. 31 0. 7160 

5. 28 . 7211 

6. 21 . 7243 

0. 52 0. 7056 

. 78 . 7061 

1. 54 . 7075 

1. 65 . 7076 

2. 18 . 7088 

HUNTINGTON LAKE INTRUSIVE EPOCH 

D-L---- Granodiorite of 208 208 2. 90 0. 7098 

"Dinkey 

Creek." 2 __________ do _________ 1 173 1 264 1. 91 . 7085 5 __________ do _________ 1 270 1 107 7. 31 . 7162 

SANTA LUCIA MOUNTAINS, MAIN JUNIPERO SERRA PLUTON 

SL-30 ___ Biotite-horn- 22. 8 761 0. 09 0. 7082 

blende 

31A_ gabbro. 

Biotite- grano- 1 149 1 427 1. 02 . 7099 

diorite. 

29B_ Aplite __________ 1 175 1 302 1. 68 . 7109 

• SrB7fSrM corrected ror fractionation by normalizing observed Sr&G/Srsa ratios to 0.1194. I Rubidium and strontium concentrations by isotope dilution. All other concen- trations by X-ray fluorescence. Constants: 

RbB7: >.p==l.39XIO-IIyr-1 

0.28;i g/g R b 

SrB7fSrss-:l:o.0010 at 05 percent confidence level ror a single analysis. Rubidium and 

strontium concentrations by Isotope dilution are :1:2.0 percent. Rubidium-strontium 

ratios determined by X-ray fluorescence are :1:3.0 percent. Rock ages derived from 

tho Isochrons are :1:10 percent owing to analytical uncertainty and to the small spread or Rb/Sr ratios In most or the series investigated. 

(Ross, 1965) . Potassi urn -argon ages of biotite-hornblende pairs from most specimens are grossly discordant. The zircon ages, however, cluster around 180 

m.y. and the maximum hornblende age is 183 m.y. 

(I{istler and others, 1965; R.oss, 1965). Thus an age of 

approximately 180 m.y. is considered to mark the time 

of earliest intrusion by magma within this event. As in 

the other older granitic rocks, mineral ages of rocks. of 

the Inyo Mountains intrusive epoch become more reduced and discordant with proximity to the Late Cretaceous granitic rocks near t.he crest of the Sierra 

Nevada. Hornblende potassium-argon ages indicate the 

Inyo Mountains intrusive epoch spans the time interval 

from 180 to 160 m.y. ago and is Early and Middle 

Jurassic in age. 

LEE VINING INTRUSIVE EPOCH OF MIDDLE AND LATE 

TRIASSIC AGE 

The Lee Vining intrusive epoch is here assigned to 

the period of time during which granitic rocks that 

include the granodiorite of Mono Dome and the quart:z; 

monzonite of Lee Vining Canyon that are exposed to 

the east of the Tuolumne Intrusive Series in the Sierra 

Nevada and in the vicinity of Mono Lake were emplaced 

(Kistler, 1966a, 1966b). The Late Cretaceous quartz 

monzonite of Aeolian Buttes intrudes the quartz monzonite of Lee Vining Canyon in exposures west of Grant 

Lake in the June Lake Loop (Kistler, 1966a). We have 

also seen ·a porphyritic granodiorite intruded during 

the Lee Vining intrusive epoch that is intruded by an 

equigranular quartz monzonite of the Inyo Mountains 

intrusive epoch in Blind Spring Hill, due west of the 

northern end of the White Mountains. 

Maximum biotite and hornblende potassium-argon 

ages for rocks in this series are 210 m.y. (61008, 61026) 

and rubidium-strontium whole-rock analyses yield an 

isochron of 206 m.y. for specimens of the quartz monzonite of Lee Vining Canyon (fig. 6D, table 4). Biotite 

and hornblende ages of these Middle Triassic granitic 

rocks are reduced and grossly discordant in specimens 

collected near the Tuolumne Intrusive Series in the 

Sierra Nevada (DKA 1030, MKA 410) ; the ages are 

maximum and concordant in specimens from ex·posures 

south of Mono Lake ( 6100~, 61026). The geochronologic 

data indicate the Lee Vining intrusive epoch spans the 

time interval from 210 m.y. to 195 m.y. ago and is 

Middle and Late Triassic age. 

SUMMARY OF AGES IN ALL INTRUSIVE EPOCHS 

The potassium-argon mineral ages and whole-rock 

rubidium-strontium ages that have been discussed are 

projected onto diagrammatic sections that show the intrusive epochs of the batholithic rocks across California 

(figs. 7, 8). Potassium-argon "ages" of all mineral systems from the specimens of older rock plutons may be 

reduced near contacts with succeeding younger intrusive 

bodies. In all of the older rocks, however, samples have 

been collected sufficiently distant from younger intrusive rocks to insure that the minerals of the older rocks 

have had practically complete retention of all radiogenic 

argon generated since their initial cooling, as shown 

by their concord-ant and older ages. Ages of biotitehornblende pairs from plutons intruded during the 

Cathedral Range intrusive epoch are generally concordant. Maximum concordant ages of mineral pairs in all 

the intrusive epochs are in close agreement with either 

the whole-rock rubidium-strontium age of rocks of the 

intrusive epoch or with uranium-lead age of zircons of 

the epoch. These maximum ages are taken to mark the 

beginning of each of the five epochs of plutonism in the 
20 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Age 

(m.y.) 

210 

Pacific Ocean Coast Ranges 

EXPLANATION 

0 

190 Biotite potassium-argon age 

170 

150 

130 

110 

90 

70 

0 

Hornblende potassium-argon age 

= Granite series rubidiumstrontium whole·rock age 

0~ 

0 

0 

Huntington Lake 

intrusive epoch 

Great Valley Sierra Nevada 

0 

Yosemite Cathedral Range Lee 

intrusive epoch intrusive epoch Vining 

intrusive epoch 

FIGURE 7.-Pota.ssd.um-argon mineral ages and rubidium-stJrontium whole-rock ages for granitic rocks of the Lee Vining, 

Yosemite, Huntington Lake, anfd Oruthedral Bange intrusive epochs projected to a diagrammatic cross section of OaUfornia. Location of cross section shown on plate 2. 

Sierra Nevada and environs. The data on concordant 

biotite-hornblende ages show that the intrusive process 

takes 10 to 20 million years for a given epoch, thus 

explaining the near continuum of granite emplacement 

indicated by the concordant potassium-argon mineral 

ages. 

Analysis of the entire body of potassium-argon dates 

of this report suggests the distribution of outcrops of 

rocks of the five intrusive epochs as outlined on plate 

1. In some areas, an assignment of granitic· rocks to a 

specific epoch cannot be made on the basis of existing 

data. This fact is especially true for batholiths of southern California and the Coast Range. The data do suggest, however, that the predominant Mesozoic granitic 

rocks in these areas are about 115 to 120 m.y. old but 

do not exclude the possibility that representatives of 

older and younger Mesozoic granitic rocks are present. 

The boundaries shown for rocks belonging to the five 

epochs are not to be considered the same as contacts 

that would be drawn on a geologic map. Detailed mapping in the field may change any of the traces, but the 

gross distribution cannot vary much from that 

indicated. 

Granite emplacement during the Paleozoic in eastern 

Australia (Evernden and Richards, 1962) and during 

the Mesozoic in the Sierra Nevada covered comparable 

intervals of time. Spatial patterns of intrusion in the 

two areas, however, were different. Successive pulses of 

granitic rock were emplaced in a regular way from 

southwest to northeast in Australia with little intrusion 

of an earlier series by a later one. As shown on plate 

1, vast volumes of younger granite in the Sierra Nevada 

now occupy terranes previously occupied by older plutons. The predominant area of Middle Triassic granites 

is to the east of the Sierra Nevada in the Mono Lake 

area. Rocks of the Early Jurassic epoch occur predominantly in the Inyo and White Mountains, but also 

occur in the eastern Sierra Nevada, the western foothill 

belt of the Sierra Nevada, and the Klamath Mountains 

in northern California. East of the Sierras, there is 
GEOLOGIC INTERPRETATION 21 

Age 

170 

150 

130 

110 

90 

70 

Great Valley 

EXPLANATION 

0 

Biotite potassium-argon age 

Cl 

Hornblende potassium-argon age 

Granite series rubidiumstrontium w~ole rock age 

Sierra Nevada 

= 

\ g \\=8 o=o =ol 

~" 0 00 0 

0 0 

0 

0 

0 

lnyo and White Mountains 

>. 

.c 

"''c::: a>.S 

0 0 }~-a --<V <V 

Cl)i:i: 

0 ~ Q) 

0 0 <V (I) 

-;;g 

.... c. Q) <V c:::Q.. 

~ 

/0"-

1 \ 

1 o o \ 

Papoose Flat 

pluton 

0 

0 

0 

Bi 

Yosemite Huntington Lake 

intrusive intrusive epoch 

epoch 

Cathedral Range 

intrusive epoch 

lnyo Mountains 

intrusive epoch 

)j"'IOUUE B.-Potassium-argon mineral ages and rubidium-strontium whole-rock ages for grenitic rocks of the Inyo MoUlllltains, 

Yosemite, Hunt:Iington J...~ake, and Cathed'r'al Range intrusive epochs projected to a diagrammatic cross section of California. Location of cross section shown on plate 2. 

not much replacement of rocks of one epoch by rocks 

of another; at a few places in the In yo-White Mountain 

terrane, however, Late Cretaceous plutons crop out. 

The Mesozoic granitic rocks of southern California and 

those presently occurring in the Coast Ranges are predominantly of Early Cretaceous age, whereas the major 

mass of granites in the High Sierra are of Late Cretaceous age. 

Present spatial distribution implies that rocks of all 

five intrusive epochs were emplaced in the region now 

defined by the crestal area of the Sierra Nevada from 

the latitude of Mono Lake southward and that massive 

replacement of rocks of each earlier intrusive epoch by 

invasion during succeeding epochs has taken place. The 

axis of emplacement shifted markedly in the Early 

359-835 0-69--4 

and Late Cretaceous with associated rephicement of the 

entire central portion of the Lower Jurassic batholith. 

It is probably significant that the deepest root of the 

Sierra Nevada is beneath this region. 

UPLIFT OF PLUTONS OF THE TRANSVERSE AND 

COAST RANGES 

If the age discordance shown by KA 1582 and KA 

1582-HBD at the southern end of the Sierra Nevada 

is confirmed by additional dates, the pattern of biotite 

ages in that area may be interpreted as the result of 

uplift-as suggested by agreement of KA 1575-HBD 

(88 m.y.), KA 1575 (86 m.y.), KA 1582-HBD (86 

m.y.) associated with disagreement of KA 1582-HBD 

(86 m.y.) and KA 1582 (74 m.y.) (table 5)-the hy-
22 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

pothesis being that the discordance is the result of 

erosion of these granitic rocks to great depth. The 

explanation of the decrease in topographic height of 

the mountain range south of Mount Whitney has always 

been a problem. An explanation based upon relative 

uplift would require either a flexure of the batholith 

or extensive faulting and downdropping of the southern 

end. Faulting is not supported by field data, and flexure 

is difficult to evaluate. A third possibility is that uplift 

was continuous in direction from north to south but 

that erosion rates were greater to the south; the postulation would be that the interplay of these two factors 

lead to a topographic culmination in the vicinity of 

Mount Whitney. Such an explanation might be indicated by a biotite-hornblende age discordance at Walker 

Pass, whereas an explanation based upon warping would 

not be substantiated by such discordance. 

The potassium-argon mineral ages in the San Gabriel 

Mountains and in the Coast Range plutons are the 

youngest so far determined for Mesozoic granitic rocks 

in California. Biotite ages are as young as 61 m.y. (KA 

1680) and hornblende ages as young·as 70 m.y. (KA 

1696-HBD). Age determinations by other techniques 

show that these granitic plutons are significantly older 

than indicated by the potassium-argon determinations, 

but geologic mapping indicates that the reduced mineral 

ages for these rocks are not attributable to intrusion of 

adjacent younger intrusions. 

Another interpretation for the reduced mineral ages 

in the Coast Range plutons and in the San Gabriel plutons may be that the presently exposed 'levels of these 

rocks were once buried at depths where temperatures 

were sufficiently high to cause loss of accumulwting 

argon from the minerals dated. However, some of the 

ages of biotite-hornblende pairs are concordant. Estimates from available diffusion data indicate that a temperature of about 650°C is required for hornblende to 

lose accumulating radiogenic argon at the same rate as 

biotite at 325°C. A temperature of 650°C would be 

attained at depths of approximately 20 to 26 km, depending upon the geothermal gradient. In the Santa 

Lucia Mountains, biotite and hornblende ages are concordant at 77 m.y. (Campanian) and the plutons are 

unconformably overlain by Campanian sedimentary 

rocks. To have the reduced ages due solely to high temperature resulting from deep burial of the presently 

exposed levels of. these intrusions would require an uplift of 20 or more kilometers within a single geologic 

epoch. Since this ra·te of uplift seems excessive, thereduced ages are more likely due to a combination of 

burial, and abnormal heating and strain prior to the 

exposure of the plutons. 

The effects of strain and physica:l disruption on the 

minerals dated has to be considered a cause for the 

reduced ages in the Coast Ranges, where most of the 

basement rocks are sheared. However, there is evidence 

that strain alone cannot be the cause of argon loss from 

biotite and hornblende in this terrane. First, specimens 

of Wheeler Crest Quartz Monzonite were collected from 

the mylonite zone of the eastern frontal scarp of the 

Sierra . Nevada (specimens MT -3, MT -4, Kistler and 

others, 1965) with the intention of dating the time of 

faulting. Potassium-argon ages of biotite (69 m.y., MT3; 79 m.y., MT-4) and of hornblende (96 m.y., MT-3; 

99 m.y., MT-4) were grossly discordant in these rocks. 

The discordance indicated that the technique was useless for the purpose intended, that is, dating the time 

of faulting, but for the present discussion it is useful in 

indicating that strain results in discordant biotite-hornblende potassium-argon ages. The reduced potassiumargon ages are discordant in only one of the dated 

biotite hornblende pairs from the San Gabriel Mountains-Coast Range terrane. Second, the shearing in the 

Coast Range and San Gabriel Mountains basement 

rocks is probably due principally to Cenozoic tectonic 

events, but the concordant biotite-hornblende ages are 

all Late Cretaceous. Even though shearing of the Coast 

Range basement may have resulted in some loss of argon 

from minerals in the rocks, the two considerations made 

indicate that additional causes are necessary to explain 

the observed reduced concordant ages. 

Geologic evidence indicates that the deepest crustal 

levels exposed in California are in the basement rocks 

which lie to the west of the San Andreas fault in the 

Coast Ranges and between the San Andreas fault and 

the San Gabriel fault in southern California. Metamorphic mineral assemblages of the Junipero Serra region 

of the Santa Lucia Range are of highest amphibolite 

facies and locally granulite facies (Compton, 1966). 

Precambrian gneisses and schists of high metamorphic 

grade are exposed between the San Andreas and San 

Gabriel faults in the San Gabriel Mountains. The Late 

Cretaceous mineral ages of Early Cretaceous and older 

Mesozoic plutons may reflect the time when these rocks 

were brought into crustal regions where they could cool 

to temperatures (about 300° C) that were compatible 

with equal retention of radiogenic argon in biotite and 

hornblende. 

GRANITE EMPLACEMENT AND SEDIMENTATION 

ON THE CONTINENT 

The relation between granite emplacement in the 

Sierra Nevada during the Cretaceous Period and the 

history of sedimentation in the Sacramento-San 

Joaquin Valley to the west is shown in figure 9. While 

constructing this figure, we discovered a previously 

published figure of similar type by Chuber (1962). The 

resulting figure 9 of this paper is then a modification 
GEOLOGIC INTERPRETATION 23 

70 

80 -

90 

100 

110 

120 

w 

Albian 

Aptian 

Sedimentary history 

of Sacramento Valley 

Granite 

overlapped 

E 

Granite emplacement 

in Sierra Nevada3 

~·····w 

•••••••• 0 •• 

0 0. 0 •••• 0 •• 0 

0 ••• 0 •••• 0 0 ••• 

0. 0. 0 ••••••••• 

0. 0 0 •••• 0 •••• 0 • 

• • • • • • • 0 0 •• 0 0. 

0 •• 0 •• 0 •••• 0. 0 • 

• 0 •••••••• 0 ••• 

v 

130 Neocomian Not subdivided 

140 

Jurassic 

1 Age of system and stage boundaries only approximate 2 Foraminiferal zones of Goudkoff (1945) 3Varying width of stippled area is intended to show variation 

in volume of emplaced granite as a function of time. 

Diagrammatic only 

FrounE 9.-Relation of sedimemrt:ation in the Sacramento Valley to granite emplacement in the Sierra Nevada area (in part a 

modification and extension of Chulber, 1962). 

and extension of his. Note on figure 9 the extent of overlap of presumably Jurassic granites that has occurred in 

the Great Valley (Smith, 1964; Hoffman, 1964; Callaway, 1964). Cenomanian sedimentary rocks are known 

to overlap granites in the Great Valley, and only deeper· 

drilling farther west will determine the actual extent 

of such granitic rocks. Also, note that eastward transgression of the Cretaceous seas was continuous from the 

earliest Cretaceous to the time of the E-zone of 

Goudkoff (Forbes Shale of Edmondson, 1962), that is, 

throughout the entire period of emplacement, uplift, 

and erosion of Cretaceous granite a few tens of miles to 

the east. Duririg all of this time, most of the Cretaceous 

sediment came from erosion of the Sierra Nevada 

(Chuber, 1962). Uppermost Cretaceous sediments presently occur in the subsurface approximately 10 miles 

east of Merced (Callaway, 1964). Most of the· biotite 

in the Upper Cretaceous sediments on the west side of 

the Great Valley was derived from Cretaceous granites 

of the Sierra Nevada (Curtis and others, 1958). Only 

subsequent to the close of final granite emplacement did 

eastward transgression of the Cretaceous seas cease; 

oscillatory regression and eventual basin filling 

followed. 

On a larger scale, the total time span of Mesozoic 

intrusion in California coincides with that of the transgression of Mesozoic epicontinental seas onto North 

America. This correspondence is revealed by comparing 

the ages of California granitic rocks with data on the 

transgressing epicontinental seas. From paleogeographic maps representing various stages of the Mesozoic and Cenozoic ( Schuchert, 1955), Damon and 

Mauger (1966) plotted areas of marine deposition within the present boundaries of North America as percentages of continent inundated. We have reproduced their 

graph in figure 10. The curve clearly shows that the 

Mesozoic transgressive episode, which terminated in the 

Turonian stage of the Late Cretaceous, when 31 percent 
24 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Age 

(m.y.) 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

110 

120 

130 

140 

150 

160 

170 

180 

190 

200 

210 

220 

230 

Systern 

>-

a:: 

~ 

z 

a:: 

w 

f--

~ 

:::> 

a 

(/) 

:::> 

0 

w 

u 

~ 

f--

w 

a:: 

u 

Se- Intrusive epoch ries 

Cathedral Range 

1------+-------------

Huntington Lake 

30 25 

Area of epicontinental seas 

(percent) 

20 15 10 5 0 

1----1------t-----------

Yosemite 

lnyo Mountains 

Lee Vining 

FIGURE 10.-(For explanation see facing page.) 
GEOLOGIC INTERPRETATION 25 

of North America was inundated, had temporary but 

distinct reversals. 

Damon and 1\::fauger (1966) were concerned with the 

relationship between magmatism and orogeny in postTuronian time. On the basis of available mica-potassium-argon ages of granitic rocks in the Great Basin, 

they showed two Cenozoic deformational and plutonic 

episodes to be coincident in time with the two reversals 

in the last 60 m.y. of their curve. They suggested then 

that transgression ·and regression of epicontinental seas 

reflected orogenic events and proposed that three other 

orogenies occurred within the time intervals represented by the three major withdrawals which occurred 

during the Mesozoic. 

Our data require a refinement of this interpretation 

since. the beginning of each Mesozoic plutonic episode 

is a;pproximately coincident wd.th a peak which marks 

the beginning of a temporary reversal of the general 

transgression curve. Also plotted in figure 10 are the 

intervals of time we have deterinined for each of the 

five epochs of granitic intrusion in the Mesozoic batholiths of Californi~. The remarkable correlation between 

the presently known periods of temporary regression of 

the epicontinental seas and the periods of granite emplacement is obvious. 

CORRESPONDENCE OF INTRUSIVE AND 

DEFORMATIONAL EVENTS IN THE SIERRA NEVADA 

Immediately preceding, and in part contemporaneous 

with, each of the periods of voluminous magma intrusion, deformational events of regional extent occurred 

in California and western Nevada. The term pulse is 

used by us for each temporally related deformational 

and intrusive. event. The five pulses are described as 

follows: 

E arZy or Middle Triassic pulse (Lee Vining intrusive 

epoch) .-E·arly or Middle Triassic deformation of regional exten:t in the Sierra Nevada folded layered Permian and older sedimentary and volcand.c rocks in the 

Ritter Range pendant directly west of outcrops of 

granitic rocks intruded during the Lee Vining intrusive 

epoch (Kistler, 1966a). 

Early and Middle J urassio pulse (I nyo Mountains 

int?wime epoch) .-Folding and thrusting that was well 

advanced before the end of deposition of the Early and 

Middle Jurassic Dunlap Formation occurred in the 

areta immediately north of outcrops of Lower J ura,ssic 

granitic rocks of the In yo-White Mountains batholith 

(Ferguson and Muller, 1949). Near its base, ·the Dunlap 

Formation contains fossils characteristic of the upper 

part of the Lower Jurassic or upper Lias of the European section. 

Late J urassio pUlse (Yosemite int'I"USime epoch).-

Folds in Upper Jurassic (Oxfordian and Kimmeridgian) metamorphosed sedimentary and volcanic rocks 

in the foothill belt of the Sierra Nevada are truncated 

by· batholithic rocks of the Yosemite intrusive epoch. 

Folding and thrusting unquestionably preceded plutonic intrusion, and the two events may be considered 

component parts of a revolution according to Taliaferro 

(1942). 

Early Cretaceous pulse (Hwntington Lake·intru..sive 

epoch).-In the Santa Lucia Mountains of the California Coast Ranges, an unconformity between . the 

Marmalejo Formation of Taliaferro (1~44) of very 

early Cretaceous age, and the Jack Creek Formation 

of Taliaferro (1944) of early Late Cretaceous age, 

marks a late Early Cretaceous disturbance. In the 

Peninsular Ranges of California, a major unconformity occurs between marine strata of Late Cretaceous 

age and marine strata of Early Cretaceous and earliest Late Cretaceous ages (Jahns, 1954), the older 

rocks having been metamorphosed '8Jld then intruded by 

granitic rocks of the Huntington Lake intrusive epoch. 

Late CretaoeoUIJ pulse (Cathedral Range int'I"USive 

epoch).-In the Jackson Mountains of northwestern 

Nevada, on line with the trend of granitic rocks of the 

Cathedral Range intrusive epoch exposed in the Sierra 

Nevada, Lower Cretaceous sedimentary rocks were 

folded and then eroded before deposition of the next 

younger rock unit of Late Cretaceous or early Tertiary 

age (Willden, 1958). 

The record of the Cretaceous deformational events 

cannot be demonstrated in stratified rocks in roof pendants in most of the present physiographic SierraN evada 

(Kistler, 1966b) owing to previous intrusion of Jurassic 

and older granitic rocks. These granitic rocks were not 

susceptible to folding, as were the layered rocks folded 

on the flanks of the gran~te massifs. Local folding superimposed on Late Jurassic folds in Jurassic and 

Paleozoic sedimentary rocks in the foothill belt of the 

Sierra. Nevada (Best, 1963) may be rel31ted to either of 

the two Cretaceous deformations. 

The correlation of Californi;a tectonic and intrusive 

pulses with oscillations of the North American epicontinental seas implies that these pulses must have been 

significant throughout the entire Cordilleran region. 

EXPLANATION OF FIGURE 10 

Curve showing extent of expicontlnental seas (after Damon and Mauger, 1966) during the Cenozoic and Mesozoic Eras (time 

scale after Harland and others, 1964). Circles marked SA represent oldest dates of South American intrusive rock intervals; 

the X's marked IV-VIII represent the oldest ages of the time intervals of Gab.rielse and Reesor (1964) for intrusive rock series 

of British Columbia. 
26 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Age data from Mesozoic batholithic rocks in British 

Columbia, Canada, suggest a similar pattern. On the 

basis of rubout 50 mica potassium..:argon ages, Gabrielse 

and Reesor (1964) separate five Mesozoic intrusive 

events which they designate with numbers VIII through 

IV. The oldest age determined for granitic rocks in each 

of these episodes is plotted next to its corresponding 

number on our figure 10. Stratigraphic evidence was 

used by Gabrielse and Reesor to show unconformities 

coincident with periods VIII, VII, and V. They state 

in their concluding remarks that "There appears to be 

a succession of pulsatory events ~at ·about 30 ·million year 

intervals, established in part by stratigraphy, and in 

part by potassium -argon determinations." 

Potassium-argon dates by us from Mesozoic granitic 

rocks in the South Americrrn oordillera (Peru and Bolivia), although limited in coverage and number, indicate a similar periodic intrusive history. Of particular 

significance is the fact that the oldest Mesozoic batholithic rocks of this region are of Middle Triassic age 

(equivalent in age to the Lee Vining intrusive epoch). 

Other granitic rocks dated are equivalent in age to those 

emplU~ced in California during the Inyo Mountain and 

the Cathedral Range intrusive epochs. These data are 

shown on figure 10 and the locations of the samples of 

Middle Triassic age are given in table 5. 

CONCLUSIONS 

The emplacement of Mesozoic batholithic rocks in the 

North A·merican cordillera was accomplished during 

five major pulses of deformation and intrusion (all five 

were not demonstrated for South America by our limited data). In addition, the patterns of deposition, in 

both western California and central North A-merica, 

show that these regions were being lowered progressively by epeirogenic movement during the same period 

of time, culminating in the Turonian stage of the Late 

Cretaceous, when 31 percent of the present continental 

area was below sea level. A new geological term should 

be coined for such a profound and complex series of 

continent-wide (or hemisphere-wide) events as oocurred 

in North America during this period of combined extensive foundering and m·assive intrusion and uplift. 

The term should be defined so ·as to stress the detailed 

correspondence in time of apparently secondary features 

of the phenomenon. It should be 1also stressed that, as 

the mass of intruded granite became greater, the inund·ations became greater. Only when massive emplacement 

of granite ceased, did emergence of the continent occur. 

It is obvious that the fundamental explanation for 

mobilization of' the magmas subsequently emplaced in 

eastern California cannot be found in localized downwarping of a deep sedimentary basin. Mechanisms much 

more profound than this must be found to explain the 

detailed correspondence of events here discussed. Present geological thought would probably attempt to find a 

driving mechanism for these events, either in complimentary phase changes or by horizontal convective 

transport of vast quantities of material. Both of these 

explanations actually depend upon an even more fundamental process, that is, a perturbation of uniform heat 

flow within the mantle of the earth. Both syntheses can, 

and probably will, be extensively developed. 

REFERENCES CITED 

Banks, P. 0., and Silver, L. T., 1966, Evaluation of the decay 

constant of uranium 235 from lead isotope ratios: Jour. 

Geophys. Research, v. 71, no.16, p. 4037-4046. 

Bateman, P. C., 1961, Granitic formations in the east-central 

Sierra Nevada near Bishop, Californi-a : Geol. Soc. America 

Bull., v. 72, no. 10, p. 1521-1537. 

Bateman, P. C., Clark, L. D., Huber, N. K., Moore, J. G., and 

Rinehart. C. D., 1963, The Sierra Nevada batholith-a synthesis of recent work across the central part: U.S. Geol. 

Survey Prof. Paper 414-D, 46 p. 

Best, M.G., 1963, Petrology ·and structural analysis of metamorphic rocks in the southwestern Sierra Nevada foothills, 

California: California Univ. Pu'bs. Geol. ·Sci., v. 42, no. 3, p. 

111-158. 

Broderson, R. .A., 1962, The petrology, structure, and age relationships, Cathedral Peak porphyritic quartz monzonite, 

central Sierra Nevada, California: California Univ. 

(Berkeley), Ph. D. thesis, 287 p. 

Callaway, D. C., 1964, Distribution of uppermost Oreta.ceous 

tsands in the Sacramento-northern San Joaquin Basin of 

California : San Joaquin Geol. Soc. Selected Papers, v. 2, p. 

5-18. 

Calkins, F. C., 1930, The granitic rocks of the Yosemite region, in 

Matthes, F. E., Geologic history of the Yosemite Valley: U.•S. 

Geol. Survey Prof. Paper 160, p. 1~129. 

[christensen, M. N., 1959, Geologic structure of the Mineral King 

area, California: California Univ. (Berkeley), Ph. D. thesis. 

Chu:ber, Stewart, 1962, Late Mesozoic stratigraphy of the 

Sacramento Valley : San Joaquin Geol. Soc. Selected Papers, 

v. 1, p. 3-16. 

Compton, R. R., 1966, Granitic and metamorphic rocks of the 

S:alinian block, California Coast Ranges: California Div. 

Mines and Geology BuU. 190, p. 277-287. 

Curtis, G. H., 1951, The geology of the Topaz Lake quadrangle 

and the eastern half of the Ebbetts Pass, California quadrangle: California Univ. (Berke'ley), Ph. D. thesis, 316 p. 

Curtis, G. H., Evernden, J. F., and Lipson, J., 1958, .Age determination of some granitic rocks in California by the potassium-argon method: California Div. Mines Spec. Rept. 54, 

16 p. 

Damon, P. E., and Mauger, R. L., 1966, Epeirogeny-orogeny 

viewed from the Basin and Range province : Soc. Mining 

Engineer Trans., v. 235, no. 1, p. 99-112. 

Davis, G . .A., 1961, Metamorphic and igneous geology of preCretaceous rocks, Coffee Creek area, northern Trinity .Alps, 

Klamath Mountains, California: California Univ. 

(Berkeley), Ph. D. thesis. 
REFERENCES CITED 27 

Edmondson, W. F., 1962, Stratigraphic relations of Upper Cretaceous rocks in Great Valley, California: San Joaquin Geol. 

Soc. Selected Papers, v. 1, p.17-26. 

Ellis, A. J., and Fyfe, W. S., 1956, A note on the calcite-wollastonite equilibrium: Am. Mineralogist, v. 41, nos. 9-10, p. 

805-807. 

Evernden, J. F., and Curtis, G. H., 1965, The potassium-argon 

dating of late Cenozoic rocks in East Africa and Italy: 

Current Anthropology, v. 6, p. 343-385. 

Evernden, J. F., Curtis, G. H., Kistler, R. W., and Obradovich, 

J. D., 1960, Argon diffusion in glauconite, microcline, sanidine, leuclte, and phlogopite: Am. ·Jour. Sci., v. 258, no. 8, 

p. 583-604. 

Evernden, J. F., and J-ames, G. T., 1964, Potassium-argon dates 

and the Tertiary floras of North America: Am. Jour. Sci., 

v.262,no.8,p.945-974. 

Evernden, J. F., and Richards, J. R., 1962, Potassium-argon ages 

in eastern Australia : Geol. Soc. Australia Jour., v. 9, pt. 1, 

'P· 1-50. 

Evernden, J. F., Savage, D. E., Cul'ltis, G. H., and James, G. T., 

1964, Potassium-argon dat·es and the Cenozoic mammalian 

chronology of North America: Am. Jour. Sci., v. 262, no. 2, 

p. 145-198. 

FergUJSon, H. G., and Muller, S. W, 1949, ·Structural geology of 

the Hawthorne and Tonopah quadrangles, Nevada.: U.S. 

.Geol. Survey Prof. Paper 216, 55 p. 

Fyfe, W. S., Turner, F. J., and Verhooge.n, John, 1958, Metamorphic reactions and metamorphic facies : Geol. Soc. America 

Mem. 73, 259 p. 

Ga'brielse, H., and Reesor, J. E., 1964, Geochronology of plutonic 

rocks in two areas of the Canadian Cordillera, in Osborne, 

F. F., ed., Geochronology in Canada: Royal Soc. Canada 

Spec. Pub. 8, p. 96-128. 

Goudkoff, P. P., 1945, Stratigraphic relations of Upper Cretaceous in Great Valley, California: Am. Assoc. Petroleum 

Geologists Bull., v. 29, no. 7, p. 956-1007. 

Gromme, 0. S., 1963, Rem-anent magnetiza,tion of igneous rocks 

from the Franciscan and Lovejoy Formations, northern 

California: California Univ. (Berkeley), Ph. D. thesis, 226 p. 

Hall, W. E., and MacKevett, E. M., Jr., 1962, Geology and ore 

depo'Sits of the Darwin quadrangle, Inyo County, California : 

U.S. Geol. Survey Prof. Paper 368,87 p. 

HmnUton, W. B., 1956, Geology of the Huntington Lake area, 

Fresno County, California: California Div. Mines Spec. 

Rept. 46, 25 p. 

Harland, W. B., Smith, A. C., and Wilcock, Bruce, eds., 1964, The 

Phanerozoic time-scale--A symposium dedicated to Professor Arthur Holmes: Geol. Soc. London Quart. Jour., 

Supp., v. 120s, 458 p. 

Hart, S. R., 1964, The petrology and isotopic-mineral age relations of a contact zone in the Front Range, Colorado: Jour. 

Geology, v. 72, no. 5, p. 493-525. 

Hay, E. ~·~ 1963, Age and relationship of the Gold Hill Pluton, 

·Oholame Valley, C-alifornia, in Am. Assoc. PetroJeum 

.Geologists Soc. Econ. Paleontologists and Mineralogists, 

Pacific Section, Guidebook to the geology of Salinas Valley 

and the San Andreas fault: p. 113-115. 

Hoffman, R. D., 1964, Geology of the northern San Joaquin Valley 

[Ca.liforni-a] : San Joaquin Geol. Soc. Selected Papers, v. 2, 

p. 30-45. 

Holdaway, M. J., 1963, Petrology und structure of metamorphic 

and igneous rocks of parts of northern Coffee Creek and 

Cecil ville quadrangle, Klamath Mountains, California: 

.california Univ. (Berkeley), Ph. D. thesis, 202 p. 

Holm, J. L., and Kleppa, 0. J., 1966, The thermodynamic properties of the alum.inum silicates: Am. Mineralogist, v. 51, 

nos.ll-12,p.1608-1622. 

Hurley, P. M., Bateman, P. C., Fairbairn, H. W., and Pinson, 

W. E., Jr., 1965, Investigation of the Initial Sr87/Sr86 ratios in 

the Sierra Nevada plutonic province: Geol. Soc. America 

Bull., v. 76, no. 2, p. 165-174. 

Jaffe, H. W., Gottfried, David, Waring, C. L., and Worthing, 

H. W., 1959, Lead-alpha age determinations of accessory 

minerals of igneous rocks (1953-1957) : U.S. Geol. Survey 

Bull. 1097-B p. 65-148. 

Jahns, R. H., 1954, Geology of the Peninsular Range province, 

southern California and Baja California [Mexico]: [pt.] 3 

in Chap. 2 of Jahns, R. H., ed., Geology of southern California : California Div. Mines and Geology Bull. 170, p. 

29-52. 

Jenkins, S.· F., 1961, A structural study of a portion of the 

Kernville Series (?Jurassic; California) : California Univ. 

(Berkeley) , M.A. thesis. 

Kistler, R. W., 1966a, Geologic map of the Mono Craters quadrangle, Mono and Tuolumne Counties, California: U.S. Geol. 

Survey Geol. Quad. Map GQ-462, scale 1 : 62,500. 

-.--1966b, Structure and metamorphism in the Mono Craters 

Quadrangle Sierra Nevada, California: U.S. Geol. Survey 

Bull. 1221-E, 53 p. 

---1968, Potassium-argon ages of volcanic rocks in. Nye and 

Esmeralda Counties, Nevada : Geol. Sec. America Mem. 110. 

p. 251-262. 

Kistler, R. W., Ba:teman, P. C., and Brannock, W. W., 1965, 

Isotopic ages of minerals from granitic rocks of the central 

Sierra Nevada and Inyo Mountains, California : Geol. S'OC. 

AmeriC'a Bull., v. 76, no. 2, p. 155-164. 

Kistler, R. W., and Dodge, F. C. W., 1966, Potassium-argon ages 

of coexisting minerals from pyroxene-bearing granitic rocks 

in the Sierra Nevada, California: Jour. Geophys. Research, 

v. 71,no.8,p.2157-2161. 

Krauskopf, K. B., 1953, Tungsten deposits of Madera, Fresno, 

and Tulare Counties, California: California Div. Mines Spec. 

Rept. 35, 83 p. 

Larsen, E. S., Jr., 1948, Batholith and associated rocks of Corona, 

Elsinore, and San Luis Rey quadrangle, southern California : Geol. Soc. America Mem. 29, 182 p. 

Macdonald, G. A., 1941, Geology of the western Sierra Nevada 

between the Kings and San Joaquin River, California: 

California Univ. Pubs. Geol. Sci., v. 26, no. 2, 215-286. 

Mayo, E. B., 1941, Deformation in the interval Mt. Lyell-Mt. 

Whitney, California: Geol. Soc. America Bull., v. 52, no. 7, 

p. 1001-1084. 

McKee, E. H., 1962, The stratigraphy and structure of a portion 

of the Magruder Mountain-Soldier Pass quadrangles, California-Nevad·a: California Univ. (Berkeley), Ph. D. thesis, 

108 p. 

McKee, E. H., and Nash, D. B., 1967, Potassium-argon ages of 

granitic rocks in the Inyo Batholith, east-central California: 

Geol. Soc. America Bull., v. 78, p. 669-680. 

McKee, E. H., and Nelson, C. A., 1967, Geologic map of the 

Soldier Pass quadrangle, California and Nevada: U.S. 

Geol. Survey Geol. Quad. Map GQ-654, scale 1:62,500. 

t¥mer, W. J., 1931, Geologic sections across the southern Sierra 

Nevada of California: California Univ. Pubs. Geol. Sci., v. 

20, no. 9, p. 331-360. 

Miller, W. J., and Webb, R. W., 1940, Descriptive geology of the 

Kernville quadrangle, California: California Jour. Mines 

and Geology, v. 36, no. 4, p. 343-378. 
28 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Parker, R. B., 1961, Petrology and structural geometry of pregrani.Uc rocks in the Sierra Nev·ada, Alpine County, California: Geol. Soc. America Bull., v. 72, no. 12, p. 1789-1806. 

Rama, S. N. I., Hart, S. R., and Roedder, E., 1965, Excess radiogenic argon in fiuid inclusions: Jour. Geophys. Research, v. 

70, p. 509-511. 

Romey, W. D., 1962, Geology of a part of the Etna quadrangle, 

Siskiyou County, Cali.furni•a: California Univ. (Berkeley), 

Ph. D. thesis. 

(Ross, D. C., 1965, Geology of the Independence quadrangle, Inyo 

County, California: U.S. Geol. Survey Bull. 1181-0, 64 p. 

Schuchert, Charles, 1955, Atlas of paleogeographic maps of North 

America: New York, John Wiley & Sons, Inc. 

Sherlock, D. G., and Hamilton, W. B., 1958, Geology of the north 

half of the Mount Abbot quadrangle, Sierra NeV'ada, California: Geol. Soc. America Bull., v. 69, no. 10, p. 1245-1267. 

Slemmons, D. B., 1953, Geology of the Sonora Pass Region : 

California Univ. (Berkeley), Ph. D. thesis, 201 p. 

Smith, M. B., 1964, Map showing distribution and configuration 

of basement rocks in California: U.S. Geol. Survey Oil and 

Gas Inv. Map OM-215, scale 1 : 500,000. 

Taliaferro, N. L., 1942, Geologic history and correlation of the 

Jurassic of southwestern Oregon and California : Geol. Soc. 

America Bull., v. 53, no. 1, p. 71-112. 

---1944, Cretaceous and Paleocene of Santa Lucia Range, 

Caii:forni•a: Am. Assoc. Petroleum Geologists Bull., v. 28, no. 

4, p. 449-521. 

Weill, D. ·:~r., 1966, Stability relations in the AkOa-SiOll system 

calculated from solubilities in the AkOa-Si02-NaaAlFs sysn 

tern : Geochim. et Cosmochim. Acta, v. 30, no. 2, p. 223-237. 

Willden, C. R., 1958, Cretaceous and Tertiary orogeny in Jackson Mountains, Humboldt County, Nevada: Am. Assoc. 

Petroleum Geologists Bull., v. 42, no. 10, p. 2378-2398. 
TABLES 5 and 6 

TABLE 5 31 

TABLE 5.-Potassium-argon analyses and location of sample localities 

[Tho following ages (also shown on pl. 2) for the location numbers given were taken from previously published data: 155-166 (Curtis and others, 1958); 167-168 (Kistler and Dodge, 1966); 169-206 (localities 2-39 respectively of Kistler and others, 1965); 207-208 (Hall and MacKevett, 1962); 25Q-251 (Compton, 1966). Constants: ).~t=4.72X1o-•o 

year-•; X.=0.684X1o-•o year-•; 1.19X1Q-4 atoms K•o/atoms K] 

Location Latitude Longitude Elevation Picked (P) Size Weight K (wt Arat•o Age Ci(:r-p) 

No. KANo. (N.) (W.) (ft) orun- Mineral (standard (grams) percent) (percent) (100 yr) (percent) 

(pl.l) picked (U) mesh) 

62 67-64 37°41'43" 119°43'29" ............................... u Biotite. __ --•.•.••••.. ------------------------- 0.398 7.210 9 93.3 0.1 63 71-64 a7°42'35" 119°43'16" ............................. u ••••• do ••••••••••.•••••.•.••.•.•.•••.••.•.••.••• .332 7.516 9 92.9 .3 64 72-64 a7°43'25" 119°42'49" ------6.-2oo· u .••.• do •••••.•.••••••••..•..•...••.. 16/35 .438 7.531 11 90.0 .1 21 181-64 38°37'32" 119°32'27" p .••.• do •••••.••••.•....•.••••.•.•.•..•.••.•....• .333 7. 709 11 81.9 .0 65 579 a7°22'22" 117°58'38" ................................ u •.••• do ••••••.•••.•••.•..•.•••.••.•••..•.••.••.• .555 5.476 30 170.0 1.a 66 804 a7°01'21" 118°06'36" ............................... u •...• do ••••••...••.•••.••.•......••••.•••.•.•.•• .655 5.663 40 77.9 1.3 121 820 35°49'46" 118°28'50" .......................... u ...•• do ••••••..••••••....•.•.•.•.••••••..•••.••. 1.187 6.66 14 84.7 2.0 122 822 35°45'55" 118°24'40" u •.••• do •.•.•....•.•••...•.•......•.••.•••..•.•.• 1. 756 6.58 47 48.8 .1 4 ·828 40°59'39" 122°55'06" :::::::::::: u •..•• do •••••.•.•••••••.•.•.•.•.••.••••.••••••••. . 728 5.90 10 130 . 5 67 840 37°23'08" 117°43'47" ........................... u •.•.• do •••••••...•••.••.•...•..•.••••••.•....••• • 767 5.10 23 155 1.9 123 842 a5°49'50" 120°21'10" ............... ----...... u Hornblende .•••••..•.•••.••.......•.•..•.••.•.•..••••.•• .108 82 143 .9 68 902 37°25'36" 117°53'49" -----.................. u Biotite ••••.•.•.•••••....•......••.•...•.••.••• .360 5.608 16 162 .0 1 955 41°21'13" 122°58'10" ............................ u ...•• do •••••.•.••••.........••.••... 28/60 3.207 5.184 9 143.5 1.4 2 956 41°18'38" 1~58'24" ............................ u •.•.• do •••.•...•••••••..•....•..•••• 16/28 3.071 6.513 4 141 1.8 3 957 41°09'37" 122°58'06" u ••••• do •••••••••••.•••••••••••.•.•. 16/28 2.469 6.364 6 130 1.1 10 1482 39°53'52" 121°21'16" :::::::::::: p •.... do._ ••••....•..•.•............ 8/10 .412 7.607 6 128 .6 1438 39°63'52" 121°21'16" ......................... p Hornblende ..••••••.•.•••..•••.•.• 10/16 .627 .646 17 142 .4 11 1436 39°58'15" 121°16'37" ........................... p Biotite •••.•.•.•.••.•.•.••.•.•.•.•. 16/35 .350 7.031 10 132 .3 1437 39°58'15" 121°16'37" .......................... p Hornblende ...•••••.•.•.•.•.•....• 28/60 1.167 .550 50 136 .0 12 1438 39°45'35" 121°18'34" .......................... p Biotite .••.•••.•.••.•.••...•.•.•.•. 16/28 .318 7.335 7 126 . 1 1489 39°45'35" 121°18'34" p Hornblende ••.••••.••••••••.•••••. 16/28 1.319 . 582 24 131 .3 13 1440 39°49'44" 121°24'18" :::::::::::: p Biotite ..•...•.•.••.•.•.••.•••.•.•. 8/10 .351 7.485 6 129 .6 1441 39°49'44" 121°24'18" ------------ p Hornblende ..•.••.•.•....•.•.•.•.• 16/28 1.a72 .577 24 1a2 .2 14 1442 a9°57'57" 121°16'a7" ------------ p •..•• do .••••••....••••••.•.•.•.•.•. 28/48 1.158 .452 32 143 . 5 

1449 a9°57'57" 121°16'37" ------------ p ..... do.--------------------------- 35/48 2.451 .451 14 142 .6 167 1495 (Kistler FD-13) ------------ p Biotite ............................ 35/80 .285 7.858 19 87.4 .1 

6 1501 40°34'39" 120°441

14" 5,600 p ..... do ............................ 16/28 .330 7.142 7 123 .2 

6 1502 40°34'43" 120°43'02" 5,a50 p ..... do._ •• __ ..................... 16/28 .399 7.284 a 121 . 7 

1602-HBD p Hornblende ....................... 100/200 1.995 a.374 4 121 .1 

7 1503 40°15'44" 120°a1'38" 5,400 p Biotite ............ _._ .............. 16/28 .440 7. 733 8 97.4 .3 

8 1504 40°14'39" 121°a1'00'' 6,030 p ..... do ............................ 10/16 .a52 7.302 7 99.9 .0 

9 1506 40°07'04" 120°28'40" 5, 515 p ..... do ............................. 60/100 .294 6.893 14 101 .3 

1506-HBD p Hornblende ••••.•.•..•..••...••••• 100/150 2.907 3.017 8 102 1.0 

20 1508 39°47'a1" 120°06'25" 5,040 p Biotite ............................ 16/28 .354 7.821 7 86.8 .1 

1508-R p ..... do ............................. 16/28 .367 7.821 8 86.6 ---------- 1608-B p ••••• do ............................. 16/28 .a91 7. 549 6 88.9 . 4 

1608-B-R p ..... do ............................. 16/28 .394 7. 549 7 89.0 ---------- 16 11500 39°62'07" 120°24'07" 6,613 p ..... do .. ~ .......................... 16/28 .343 7.474 4 105 . 5 11500-HBD p Hornblende ••.•.•.•..•••.••••••••• 28/60 1. 707 .672 7 105 .3 166 1610 a9°86'38" 120°29'37" 7,000 p Biotite ............................ 10/16 .383 5.814 56 99.0 .7 

16 1511 39°37'14" 120°28'30'' 6,400 p ..... do ............................. 16/28 .353 7.438 9 97.2 .1 1611-10/16 u .•.•• do ............................. 10/16 .486 6.699 9 97.5 . 7 

1611-16/28 u ..... do ............................. 16/28 .a65 6. 176 8 98.5 .1 

1611-86/48 u ..... do ............................. 35/48 .306 6. 799 9 101 . 7 

1611-100/160 u ..... do ............................. 100/150 .420 7.093 8 101 .1 1511-HBD p Hornblende ••••••......•...•..•••• 35/60 .853 .876 15 125 . 5 17 1512 89°19'06" 120°18'54" 6,680 p Biotite ............................ 10/16 .402 7.429 11 96.7 .4 1612-HBD p Hornblende ..••••••.•...........•. 28/60 1.447 .666 27 97.8 . 5 1612-PL p Plagioclase ..••••••••••••••....•... 28/60 2.209 .299 35 92.5 .1 1512-KF p 

~:::~:~.":'.~ ::::: = :::::::: ==: =:: :: = 60/100 .448 11.54 3 100.1 • 0 1612-QTZ p 28/60 3. 507 .028 84 109 --------.-5 22 1614 38°51'59" 120°04'40" 7, 550 p Biotite •••.......•.•••••••••..•.... 16/28 .402 7.224 5 87.8 1614-HBD p Hornblende ••.••••.•.•••••••••••.. 28/100 .492 .840 27 91.4 .1 23 1616 38°58'37" 119°58'15" 7,360 p Biotite ............................ 16/28 .363 7. 557 20 86.1 .1 1616-HBD p Hornblende ................... ____ 28/60 2.107 .937 33 89.9 .6 24 1517 38°57'52" 119°51'00" 5,200 p Biotite ............................ 10/16 .392 7.359 9 83.5 . 5 26 1518 38°47'07" 119°62'50'' 7, 500 p ..... do ............................. 10/16 .347 7. 571 14 87.1 .3 

1518-R p ..... do .............. -------........ 10/i: • 361 7. 571 15 87.4 .a 26 1619 38°86'54" 120°13'21" 7,250 p ..... do ............................. 16 .327 7.445 10 91.7 . 3 1619-HBD p Hornblende •.........•.•...••••••. 60/100 . 516 .823 10 99.6 . 7 27 1620 38°42'20'' 120°06'53" 7, 720 p Biotite ............................ 16/28 .349 7. 740 4 94.3 • 5 28 1621 38°41'41" 119°44'16" 8,560 p ..... do ............................. 16/28 .493 7. 519 4 88.7 .2 29 1623 88°29"16' 119°59'03" 7,500 p ..... do .................... ~- ....... 10/16 .388 7. 632 6 89.4 .1 30 1624 38°34'56" 119°47'56" 7,600 p ..... do ............................. 16/28 .296 6.656 7 81.8 .a 

38 1626 87°49'29'' 119°30'05" 8,800 p ..... do ............................. 10/16 .398 7. 501 10 82.1 • 7 69 1626 37°51'00" 119~6'45" 8,800 p ••••• do ............................. 10/16 .358 7. 778 8 82.4 .1 1626-R p ..... do ........................... _. 10/16 .472 7. 778 7 83.7 . 1 

70 1527 37°51'08" 119°26'38" 8,800 p ..... do ......... _ ................... 10/16 .349 7.602 15 81.9 .o 1527-8/10 u ..... do ............................. 8/10 .419 7.315 10 80.2 .8 1527-10/16 u ..... do ............................. 10/16 .477 7.166 7 80.0 .4 

1527-16/28 u ..... do ............................. 16/28 .375 6.880 8 82.0 .3 1527-36/48 u ..... do ............................. 35/48 .419 4.344 8 85.7 .1 

1527-48/60 u ..... do ............................. 48/60 .353 3.171 10 86.9 1.5 1627-60/100 u ..... do ............................. 60/100 .354 2.825 12 84.7 .1 1527-100/150 u .•.•. do ..•.••••.•.••.••••......•.... 100/150 .674 1.630 29 90.8 .6 71 1628 3~52'84" 119°23'38" 8,800 p ..... do ............................. 16/28 .373 6.845 12 84.6 .7 72 1580 8~47'42" 119°23'42" 9,000 p ..... do ........................ ~-- •. 10/16 .395 7.058 12 83.7 .2 73 1581 87°45'26" 119°23'42" 9,000 p ..... do ............................. 16/28 .350 7.443 10 83.6 .3 74 1582 37°51'13" 119°17'50" 8,800 p ..... do ............................. 10/16 .365 7. 581 7 83.2 .4 76 1588 37°61'44" 119°17'49" 8,800 p ..... do ............................. 16/28 .334 7. 545 11 82.5 .4 1588-HBD p Hornblende ••••••••••.•••.••.•.... 28/60 1.678 .670 a9 84.3 .o 1588-PL p 

~l!!~J~~~-~~::::: ::::::::::::::::: 60/100 1.993 .310 61 70.a 3.0 1588-KF p 28/35 .400 11.95 2 73.5 . 5 1588-QTZ p 28/60 5.220 .026 78 88.9 81 1584 38°35'06" 119°41'42" 6,640 p Biotite •...••.••••••••••••••••.•.•. 16/28 .372 6, 272 8 82.1 .2 1586 38°21'00" 119°39'08" 10,200 p " .... do ............................. 16/28 .371 7.444 12 82.8 .7 32 1636 38°251

45" 119°44'60". 7,460 p ..••• do ............................. 16/28 .438 7.286 7 81.7 .0 33 1587 38°20'27" 119°49'27" 5, 831 p ..... do ............................. 16/28 . 367 7.247 7 84.3 .8 34 1638 38°21'49" 119°62'18" 5,520 p ..... do ........ · .•••.•.•.•••.•.••••.• 8/10 .. 843 7.591 5 83.0 .1 1638-R p ..... do ............................. 8/10 .407 7. 591 8 83.6 .1 1638-HBD p Hornblende •.••••••••••••••••••.•. 28/60 2.030 .585 23 84.2 .2 35 1589 38°19'35" 119°55'07" 6,410 p Biotite ............................ 10/16 .474 7.834 8 87.0 .2 1589-HBD p Hornblende •.•.•••.••••••••.•••.•. 28/35 2.026 .821 13 90.1 .6 
32 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

TABLE 5.-Potassium-argon analyses and location of sample localities-Continued 

Location Latitude Longitude Elevation Picked (P) Size Weight K (wt Arat•o Age cSc:o-v) No. KA No. (N.) (W.) (ft) or un- Mineral (standard (grams) percent) (percent) (106 yr) (percent) (pl.1) picked {U) mesh) 

36 1540 38°17'05" 119°57'56" 6,080 p Biotite. ___________________________ 10/16 .352 7. 767 7 88.7 .0 1540-HBD p Hornblende _______________________ 60/100 1.980 .839 33 96.7 .6 37 1541 38°11'59" 120°00'07" 5, 250 p Biotite. ___________________________ 10/16 .349 7. 705 6 94.4 . 7 1541-R p _____ do _____________________________ 10/16 .335 7. 705 7 94.0 . 7 1541-HBD p Hornblende .. --------------------- 28/60 2.309 • 736 14 97.8 .9 1541-PL p Plagioclase. _______________________ 28/60 1.926 . 233 42 90.7 .1 1541-KF p K-feldspar ________________________ 28/35 .405 12.25 3 83.5 . 5 1541-QTZ p Quartz. ___________________________ 28/60 2. 776 .019 92 108 38 1542 38°22'51" 119°52'14" 7, 650 p Biotite. __________________________ 10/16 .487 7. 713 7 84.8 .5 39 1543 38°22'54" 119°52'07" 7,600 p ..... dO----------------------------- 10/16 .315 7. 676 6 82.9 .3 1545 38°17'19" 119°43'06" 7,360 p ..... dO----------------------------- 16/28 .340 7.369 8 82.7 .4 40 1546 38°24'58" 119°50'00" 7, 560 p _____ do _____________________________ 8/10 . 349 7.330 5 84.2 . 3 41 1547 38°25'05" 119°49'47" 7,400 p ..... dO----------------------------- 10/16 . 370 7.347 4 85.6 .4 42 1548 38°~6'45" 119°40'12" 7,600 p _____ do _____________________________ 35/48 .213 6.994 9 81.5 .1 1548-R p ___ .. do _____________________________ 35/48 .182 6.994 6 81.8 .1 43 1549 38°25'31" 119°42'17" 7, 500 p _____ do _____________________________ 16/28 .453 7.102 8 81.1 .2 44 1550 38°23'56" 119°36'26" 10,040 p _____ dO-----------------------·----- 16/28 .. 342 6. 682 9 79.5 .2 76 1551 37°27'15" 118°50'19" 11,500 p _____ do _____________________________ 16/28 . 431 7.009 6 79.1 .2 77 1552 37°26'06" 118°50'06" 9,000 p ..•.. do.---------------------------- '16/28 .397 6. 792 10 78.1 .0 78 1553 37°25'08" 118°46'04" 11,500 p _____ do _____________________________ 10/16 .464 7; 142 15 78.8 .0 1553-HBD p Hornblende. ______________________ 60/100 .800 .719 42 77.4 .4 79 1554 37°02'38" 118°31'41" 11,500 p Biotite. ___________________________ 16/28 .328 7. 212 7 80.1 . 1 80 1555 37°03'11" 118°34'46" 8, 080 p ..•.. do _____________________________ 16/28 .379 7.067 8 80.1 . 3 94 1556 36°46'27" 118°22'50" 11,500 p ..•.• dO-----------------~----------- 16/28 .368 7.451 11 82.1 .4 81 1559 37°39'15" 119°05'27" 9, 247 p ..•.. do _____________________________ 16/28 .354 7.621 12 78.7 . 1 82 1560 37°39'10" 119°05'27" 9, 000 p ..... do _____________________________ 28/35 .377 7.973 12 77.4 . 4 83 1561 37°20'27" 118°45'58" 11,500 p _____ do _____________________________ 16/28 .335 6.845 8 79.6 .8 126 1562 35°43'58" 118°23'28" 2,800 p _____ do _____________________________ 16/28 . 366 7.177 8 86.6 .0 127 1563 35°59'13" 118°29'47" 4, 000 p ___ .• do _____________________________ 28/35 .387 7.486 7 89.7 . 1 95 1564 36°03'15" 118°32'23" 6, 200 p _____ do _____________________________ 10/16 .349 7.528 16 88.5 .2 1564-HBD p Hornblende _______________________ 28/60 1. 916 1.070 11 95.6 .9 1564-PL p Plagioclase. _______________________ 28/60 2.154 .277 49 72.6 .8 1564-KF p K-feldspar __ ------- _______________ 35/48 .495 11.69 2 87.5 . 3 1564-QTZ p Quartz _______________ .. _ .••...... _ 28/60 3.323 .014 92 57.9 ---------- 96 1565 36°07'33" 118°33'22" 6, 730 p Biotite .. ___ ... _ .. _ .. __ . ___ •. _ •... _ 16/28 .351 7.472 6 87.5 .3 97 1566 36°09'03" 118°34'57" 5,800 p ..•.• do _____________________________ 16/28 . 317 7.618 9 87.8 .0 1566-R p _ .•.• do ______ . __ ... _ ....... __ ... _ .. _ 16/28 .354 7. 618 10 88.2 .0 1566-B p _____ do _____________________________ 16/28 .309 7. 548 7 88.7 .5 . 1566-B-R p ..•.• do _____________________________ 16/28 .371 7. 548 9 88.2 . 5 98 1568 36°09'12" 118°14'39" 2,000 p ..•.• dO----------------------------- 16/28 .388 7. 522 7 91.5 .0 1568-HBD p Hornblende .. _. __ ._. __ ._. ____ ._ ... 16/28 1. 033 .877 17 96.3 . 5 124 1569 35°44'36" 118°54'12" 1,100 p Biotite •. __ ........ ____ . __ ._. ____ ._ 10/16 .353 7. 971 5 102 .1 1569-HBD p Hornblende. __ . __ ._._. ___ .. ____ .. _ 28/60 1. 714 . 590 24 108 .3 1569-PL p Plagioclase .... _. ___ ._. ___ . ___ . __ .. 60/100 2.015 . 774 20 102 2.0 1569-KF p K-feldspar __ ... ---------------- ___ 28/60 . 265 9. 253 6 100 . 5 1569-QTZ p Q.uartz ____ ....• ____ . ____ . __ .. ______ 28/60 2. 619 .041 91 58 125 1570 35°42'57" 118°48'58" 1, 925 p Biotite. __ . ___ . ____ .. ____ . __ ..• _ .. _ 8/10 .427 7.829 9 98.0 .1 157Q-HBD p Hornblende_._. ____ • __ . __ . ____ ... _ 28/60 1. 948 .493 18 102 . 7 128 1571 35°42'21" 118°45'06" 3,200 p Biotite ............. __ -~-------- ___ 16/28 .348 7. 527 10 98.2 . 5 129 1572 35°44'17" 118°38'56" 4,000 p ..•.. do _____________________________ 10/16 .362 7. 556 10 92.3 .0 130 1573 35°44'51" 118°35'14" 4,875 p ..•.. do _____________________________ 16/28 .332 7.657 11 90.6 .1· 

131 1574 35°44'00" 118°32'52" 5, 780 p _____ do _____________________________ 16/28 .356 7.273 10 87.7 .1 132 1575 35°41'38" 118°29'51" 3, 750 p _____ do _____________________________ 16/28 .360 7.127 15 85.5 .0 1575-HBD p Hornblende _______________________ 28/60 1.364 1.066 12 87.7 .6 133 1576 35°39'24" 118°29'06" 2, 700 p Biotite. _______________________ .. __ 16/28 .403 7.392 9 87.0 .3 134 1577 35°39'05" 118°24'54" 2,850 p ..•.. do _____________________________ 16/28 .339 7.042 13 85.1 .3 135 1578 35°39'24" 118°19'17" 2,625 p ..•.. do _____________________________ 10/16 .367 7. 692 10 79.2 .2 136 1579 35°41'48" 118°12'50" 2,800 p _____ do ________ ------ _______________ 35/48 . 389 7. 335 9 78.7 . 4 137 1580 35°43'46" 118°10'00" 2,900 p _____ do _____________________________ 48/60 . 277 7.393 13 78.2 .6 138 1581 35°45'01" 118°06'19" 3,450 p _____ do ___________________________ . 35/48 .390 6.884 20 66.1 .4 139 1582 35°41'45" 118°03'18" 4,410 p _____ do ______ ---- ___________________ 16/28 .385 7. 620 21 74.0 . 9' 1582-HBD p Hornblende __________________ . __ .. 16/28 2.038 .905 17 86.2 . 5 99 1583 36°35'44" 118°06'10" 4,370 p Biotite. ____________________ . ______ 10/16 .440 7. 583 13 81.8 . 5 100 1584 36°35'10" 118°14'30" 8,480 p ..•.• do _____________________________ 16/28 .370 7.373 11 79.1 .2 1584-HBD p Hornblende. __ . ___________________ 60/150 1. 914 . 620 37 80.0 .4 101 1585 36°17'10" 118°08'20" 9,500 p Biotite ... ____ ------ _______________ 16/28 .479 7.047 6 79.8 .8 102 1586 36°25'04" 118°16'23" 9,680 p _____ do _____________________________ 10/16 .360 7. 632 10 80.5 .4 103 1587 36°35'04" 118°24'09" 9,280 p _____ do _____________________________ 10/16 .393 7.623 4 78.4 .6 1587-R p _____ do _____________________________ 10/16 .338 7.623 10' 78.4 .6 1587-HBD p Hornblende. ____________________ ._ 60/100 1.694 • 508 14 84.0 .6 104 1588 36°34'25"' 118°19'06" 11,530 p Biotite. ___________________________ 16/28 .396 6. 944 7 81.8 .2 105 1589 36°39'08" 118°22'02" 11,500 p _____ do _____________________________ 16/28 .350 7.170 16 79.6 . 5 106 1590 36°33'34" 118°17'27" 13, 777 p _____ do _____________________________ 16/28 .354 7. 391 11 81.9 .6 159o-R p _____ do _____________________________ 16/28 . 227 7. 391 16 81.5 .6 107 1591 36°34'02" 118°16'05" 11,600 p _____ do _____________________________ 16/28 .335 6.932 7 79.3 .8 108 1592 36°35'34" 118°13'18" 7,680 p ..... do _____________________________ 10/16 .397 7. 725 8 80.1 . 1 1592-HBD p Hornblende. ___________________ . __ 28/60 2.069 .459 20 81.5 .6 1593 37°50'52" 119°24'17" 10,900 p Biotite_ . ___ . _ . __ .. _____ . _____ . ___ . 16/28 .336 7.100 7 83.4 .9 84 1594 37°52'41" 119°20'38" 8, 700 p _____ do •.. ------------------------- 16/28 .410 7.120 9 82.4 . 1 45 1595 38°07'24" 119°25'39" 11,000 p _____ do ____________________________ 16/28 .441 7. 296 10 81.0 .8 46 1596 38°07'32" 119°26'08" 9,200 p _____ do ____________________________ 28/48 .475 6.979 9 81.4 . 1 47 1597 38°08'54" 119°25'36" 7, 950 p _____ do ____________________________ 16/28 .402 7.435 5 80.2 . 1 48 1598 38°08'54" 119°23'19" 7,300 p ..... do ____________________________ 16/28 .368 7. 598 9 80.1 . 1 49 1599 38°10'16" 119°31'02" 9,000 p ..... do ____________________________ 16/28 .437 7.208 10 81.4 . 5 85 1600 37°09'11" 118°42'51" 11,500 p _____ do ____________________________ 28/35 . 361 6.464 11 83.8 .3 

86 1601 37°11'28" 119°40'00" 12,880 p · . __ .. do .• _________ .. ___________ . ___ 10/16 .364 7. 276 9 82.5 . 5 1601-HBD p Hornblende. ________ . ___________ ._ 28/60 2.065 • 770 12 88.4 . 8 109 1602 36°27'05" 118°47'48" 2,400 p Biotite. ___________________________ 10/16 .383 7.626 6 91.7 . 1 

110 1603 36°26'56" 118°46'24" 3,050 p _____ do ____________________________ 10/16 .354 7. 716 8 92.6 . 1 111 1604 36°25'54" 118°45'18" 3, 900 p ..•.. do _________ c __________________ 16/28 . 367 7.193 25 82.7 . 3 112 1605 36°26'20" 118°44'22" 4,050 p _____ do ____________________________ 10/16 .367 7. 531 15 87.4 . 2 

1605-HBD p Hornblende __________________ . ____ 28/60 1.338 . 888 20 90.1 . 2 

1605-PL p Plagioclase _____ ---- _______________ 60/100 2.027 . 254 31 88.1 . 6 

1605-KF p K-feldspar __ ---------------------- 28/60 . 481 11.67 2 87.0 .3 

113 1606 36°26'29" 118°43'12" 4,800 p Biotite. ______________________ • ____ 10/16 .390 7. 239 19 88.5 . 6 
TABLE 5 33 

TABLE 5.-Potassium-argon anaZyses and Zocation of sampZe ZooaZities-Continued 

Location Latitude Longitude Elevation Picked (P) Size Weight K (wt Ar.~•o Age 8(..-~) 

No. KA No. (N.) (W.) (ft) or un- Mineral (standard (grams) percent) (percent) (100 yr) (percent) 

(pl.1) picked (U) mesh) 

114 1607 36°27'48" 118°37'56" 7,000 p Biotite __________ ---- ____ ---- ______ - 8/10 .436 7. 536 26 88.9 .4 

115 1608 36°27'22" 118°33'22" 12,340 p .•.•• dO----------------------------- 16/28 .368 7.099 15 90.5 .1 

1608-R p ....• dO----------------------------- 16/28 .374 7.099 10 93.2 .1 

116 1609 36°27'48" 118°32'46" 10,800 p •..•• dO----------------------------- 16/28 .334 7.290 13 87.4 . 3 

1609-HBD p Hornblende. ______________________ 28/60 1. 774 .974 17 93.0 .1 

117 1610 36°27'37" 118°33'43" 11,600 p Biotite---------------------------- 28/60 . 291 6. 773 19 88.3 .6 1619-HBD p Hornblende _______________________ 28/60. 1.656 2.136 14 86.4 2. 0 

140 1621 35°12'43" 118°32'42" 2, 700 p Biotite._---_---------------------- 10/16 .323 7.272 19 81.2 .4 

50 1624 38°04'18" 120°10'46" --·--------- p ...•• dO----------------------------- 16/28 .300 7. 727 6 138 .3 

1624--HBD p Hornblende •. -------------------_- 28/60 1. 517 . 727 11 136 .3 

118 1626 36°26'35" 118°M'13" ------------ p 

Biotite _______ -·- ________________ -_- 8/10 .280 7. 729 17 93.5 . 5 

1626-HBD p Hornblende. ______________________ 28/60 2.148 . 617 25 101 .6 87 1627 37°17'45" 119°31'52" ---·-----·-· p Biotite •••.• _____ --- ___ -- __ -- _____ -- 10/16 .206 7. 694 8 97.7 . 5 

1627-HBD p Hornblende. ______________________ 28/60 2.061 .628 30 100 . 5 

88 1628 37°19'05" 119°39'20" ------------ p Biotite----------------------------- 16/28 .280 7. 768 14 104 .4 

1628-HBD p Hornblende ________________________ 16/28 2.051 . 721 18 144 .2 

119 1629 36°23'33" 118°57'55" ------------ p Biotite ..... ------------------------ 10/16 .305 7. 564 8 103 .3 

1629-HBD p Hornblende _______________________ 28/60 2.227 .456 26 105 . 4 

120 1630 36°17'45" 119°04'40" ------------ p 

Biotite. ___ • ______________________ - 28/60 .218 6.MO 13 114 • 2 1639-HBD p Hornblende. _____ - _____ - _________ - 28/60 .915 1. 762 11 115 . 7 142 1631 34°53'49" 118°55'01" ------------ p Biotite •• --. ____ -_-- __ ---_- _______ - 28/60 .278 7.349 21 86.1 . 1 

89 1632 37°58'45" 120°20'03" -----------. p .•••• dO----------------------------- 16/28 .261 7.438 10 152 .1 

1632-HBD p · Hornblende _______________________ 16/28 1. 773 .955 26 162 . 1 

61 1633 38°25'00" 120°27'01" ------------ p Biotite. ___ • __________ -_----------- 16/28 .210 7.805 16 89.1 .0 

1633-HBD p Hornblende. ______________________ 16/28 1.893 .839 17 120 . 0 

90 1634 37°59'29" 120°16'37" ------------ p 

Biotite .• __ • __________ • _______ • ___ - 16/28 .244 7. 763 5 144 . 3 

1634-HBD p Hornblende _______________________ 28/60 2.032 1.020 10 156 .9 

51 1635 38°18'02" 120°16'38" ------------ p Biotite. __ - _____ ------------------- 16/28 .261 7.812 20 125 .1 

1635-HBD p Hornblende. ___________ • _____ • ____ 28/100 2.118 1. 368 4 148 . 1 

52 1636 38°23'16" 120°11'01" ------------ p Biotite •. _________ -. ____ -_-- ______ - 28/60 .204 7. 535 11 96.0 .6 1662-HBD 38°23'16" 120°11'01" ---·--------- p 

Hornblende. _____ -- _______________ 28/60 2.076 .956 19 95.8 .4 

91 1663-HBD 37°40'43" 119°45'47" -----------· p •..•• dO----------------------------- 16/28 1.171 1.004 11 101 . 5 

53 1664 38°13'01" 120°22'13" ------------ p Biotite. ______ -_------------------- 16/28 .311 7. 315 9 145 .6 1664-HBD p Hornblende. ______ • __________ • ____ 28/60 1.269 . 713 11 148 . 6 92 1665-HBD 37°33'07" 119°40'53" -----------· p ••••• dO----------------------------- 28/60 2.114 . 783 9 108 . 4 

93 1666 37°06'25" 119°44'36" ------------ p Biotite. ___ • __ ------ ____ ----------- 28/60 .364 7. 709 5 107 . 5 141 1667 35°01'35" 118°20'50" -----·------ p ..••• dO----------------------------- 28/60 .339 7.207 13 80.4 . 1 

1667-HBD p Hornblende. ______ • _______________ 28/60 1. 891 .936 17 81.4 .0 

143 1668-HBD 34°39'34" 118°27'38" -----------· p _____ dO----------------------------- 16/28 2. 511 1. 075 16 70.6 . 5 144 1679-HBD 34°46'57" 119°03'32" -----------· p •..•. dO----------------------------- 28/60 2.412 1. 213 5 69.7 . 3 

145 1671-HBD 34°29'19" 117°52'01" 3,300 p .•••• dO----------------------------- 10/16 2.015 .834 10 76.9 .1 

146 1672 34°50'35" 119°21'06" 3, 950 p Biotite. ___________ • ______________ • 28/60 .390 7.646 14 67.2 .0 

1672-HBD p Hornblende _______________________ 28/60 2.272 1.069 11 69.5 • 5 

147 1673 34°49'28" 118°69'27" 6,450 p Biotite. __________ -.-_---------.--- 28/60 .414 7.393 5 76.9 .3 

148 1674 34°27'56" 117°51'41" 3, 600 p .•.•• dO----------------------------- 16/28 .336 7.329 13 68.1 .1 

1674-HBD p Hornblende. ______ • _______________ 16/28 2.193 1.028 29 73.1 .1 

149 1675 34°20'61" 117°55'15" 6,810 p Biotite. ______ -_---.--------------- 16/28 .337 7. 600 13 64.7 . 1 

150 1676 34°41'56" 118°56'00" 3,800 p •••.• dO----------------------------- 28/60 .327 7.485 5 66.1 . 7 151 1677 34°09' 116°58' 5,800 p __ -.• do _____________________________ 16/28 .314 7. 574 5 69.7 . 5 

1677-HBD p Hornblende. ___ • __ •• ______________ 16/28 3.014 .866 9 72.6 .2 M 1678 38°47'02" 120°12'53" 5,360 p Biotite. __ -- __ -- ___ ._-------------- 16/28 .331 7.467 13 92.8 .1 

1678-HBD p Hornblende. ______ •• __ •• __________ 16/28 2.414 . 668 9 97.6 .6 55 1679 38°48'20" 120°07'18" 6,310 p Biotite. ________ ----_-------------- 16/28 .338 7. 515 6 93.7 . 1 

152 1680 34°15'47" 117°39'07" 7,220 p _____ do ___ ------------------------- 28/60 .341 6. 578 9 61.0 • 6 1689-HBD p Hornblende. ______ • ______________ - 28/60 2.135 1.057 42 71.5 . 7 153 1682-HBD 34°52'M" 118°M'04" 3,150 p ___ .• do. ___________ • _______________ 16/28 2.179 .324 43 77.4 .2 

56 1683 38°45'50" 120°19'38" 3,880 p Biotite. ____ • ______ • ______ -- __ -_--- 10/16 .318 7. 587 3 102 . 8 

1683-HBD p Hornblende. ______ • _______________ 10/16 2. 525 . 597 8 100 .2 1M 1696 34°18'42" 118°08'15" 2,930 p Biotite. ___________ • ____ ----------- 28/60 .340 7. 550 22 65.8 . 6 1696-HBD p Hornblende _______________________ 28/60 1.683 .864 10 70.0 . 7 57 1697 38°27'05" 119°27'29" 6,020 p Biotite. __________ -- ___ - __ --_--- __ - 16/28 .295 7.286 3 119 . 7 58 1698 38°46'15" 120°23'01" 3, 600 p _____ do.--------------------------- 28/60 .293 7. 538 6 108 . 1 1698-HBD p Hornblende. ______ • _______________ 28/60 1. 581 . 775 6 140 . 7 59 1699 38°46'23" 120°25'45" 3,400 p Biotite. __________________ -.-.-_--- 28/60 .365 7.875 16 117 .o 

1699-HBD p Hornblende. ______________________ 28/60 1.665 . 713 4 140 .4 

60 1709-HBD 38°46'17" 120°29'34" 3,320 p ••••• do ____________________________ 16/28 2. 522 .468 28 138 .2 

18 1701 39°22'30" 121°05' 1, 600 p Biotite •• __________________ • _______ 16/28 .298 7.838 4 143 .2 

1701-HBD p Hornblende. ______________________ 16/28 2.245 . 576 25 146 .2 

19 1702 39°37'00" 129°27'06" 5, 760 p Biotite. ________________________ --- 28/60 .303 7.153 3 153 . 1 1702-HBD p Hornblende _______________________ 28/60 2.097 . 773 5 150 . 4 209 DKA 1028 37°57'10" 119°14'06" ------------ u Biotite. __ ------ __ ---- ____ --------- 60/80 .297 7.495 8 83.7 ---------- 210 DKA 1029 37°57'10" 119°14'06" ------------ u ...•• dO----------------------------- 80/100 .222 7.412 10 84.8 ---------- MKA409 37°57'10" 119°14'06" ------------ u Hornblende _______________________ 100/150 1. 501 . 777 29 94.8 ---------- 211 MKA41 37°55'50" 119°14'30" ------------ u Biotite .•. ---------- ____ ----------- 80/100 .698 6.050 11 93.9 ---------- 212 DKA 1031 37°57'11" 119°14'06" ------------ u •..•• dO----------------------------- 80/100 .241 7. 528 6 83.2 ---------- DKA 1032 37°57'11" 119°14'06" ------------ u Hornblende. ______________________ 100/150 1.478 .653 22 92.8 ---------- 213 DKA 1030 37°57'40" 119°12'30" ------------ u Biotite ___________ ---------·- ______ 80/100 .301 7.669 10 99.0 ---------- MKA410 37°57'40" 119°12'30" ------------ u Hornblende. ______________________ 100/150 2.696 .446 22 206.0 ---------- 214 BKA558 37°58'00" 119°12'22" ------------ u Biotite.-- _________________________ 60/80 1. 061 6.250 33 82.0 ---------- 215 MKA42 37°56'05" 119°10'00" ------------ u _____ dO----------------------------- 40/60 1.014 6. 960 9 89.6 ---------- 216 BKA 488 37°51'30" 119°04'52" ------------ u ..••• dO----------------------------- 80/100 1.109 7.470 12 87.7 ---------- 61-192 37°51'30" 119°04'52" ------------ u Hornblende. ______________________ 100/150 .993 .377 15 85.5 ---------- 217 BKA 487 37°46'20" 119°04'58" ------------ u Biotite.------ _____________________ 40/60 .671 7.450 21 87.9 ---------- MKA458 37°46'20" 119°04'58" ------------ u Hornblende. ___ . __________ • _______ 100/115 1. 077 . 643 43 97.1 

218 BKA556 37°46'50" 119°13'55" ------------ u Biotite._--- ____ ------- ____________ 60/80 1. 544 6.820 12 82.4 ---------- 219 BKA 557 37°45'05" 119°10'00" ------------ u _____ do.---------------------------- 60/80 .840 6.240 22 69.0 ---------- 220 61-041 37°06'25" 119°44'36" ------------ u Muscovite _________________________ 35/80 • 580 8. 580 7 109.9 ---------- 61-042 37°06'25" 119°44'36" ------------ u Biotite. __ ---------- ______ ------ ___ 35/60 .442 7. 530 13 110.0 ---------- 221 61-001 37°15'50" 118°45'48" ------------ u _____ dO----------------------------- 60/80 • 559 7.340 9 80.3 ---------- 61-Q20 37°15'50" 118°45'48" ------------ u Hornblende. ______________________ 80/100 1.490 .607 12 83.3 ---------- 222 MKA 51 36°33'40" 117°M'20'' ------------ U Biotite. __ • _______ ------ ___________ 60/80 .311 3.400 21 134.0 ------·--- 201 61-047 36°55'10" 118°08'09" ------------ u Hornblende _______________________ 100/115 .621 . 599 12 155.5 ------·--- 203 61-043 36°49'48" 118°02'05" ------------ u _____ dO----------------------------- 80/100 .945 . 569 15 163.1 ---------- 223 61-045 36°44'58" 118°02'10'' ------------ u _____ dO----------------------------- 100/115 .623 :487 17 177.6 ---------- 224 61-044 36°39'47" 117°59'05" -----·------ u ••.•• do _____________________________ 100/115 .437 1.050 15 162.6 ---------- 225 61-005 37°56'20" 118°20'10'' ··---------- u Biotite .• _. _______________ -- ______ - 80/100 .859 6.960 6 156.7 ----------
34 CHRONOLOGY. OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

Location No. 

(pl.1). 

226 

227 

228 

229 

230 

231 

232 

233 

234 

235 

236 

237 

238 

239 

240 

241 

242 

243 

244 

245 

246 

247 

248 

249 

KANo. 

591 

620 

634 

1466 

1158 

1159 

1145 

1155 

1454 

1374 

615 

TABLE 5.-Potassium-argon analyses and location of sample localities-Continued 

Latitude Longitude Elevation Picked (P) Size Weight K (wt KA No. (N.) (W.) (ft) orun- Mineral (standard (grams) percent) 

picked (U) mesh) 

61-Q19 37°47'05" 118°28'30'' ------------ u Biotite ....... --_------------------- 60/80 .599 7.060 61-Q25 37°47'05" 118°28'30" ------------ u Hornblende. ____ • ____ • ____________ 100/115 1.339 • 744 51-166 37°47'05" 118°28'30" ............................. u Biotite. ___________________________ 60/80 • 504 7.010 61-Q03 37°55'50" 118°49'50" ------------ u . •..• dO---------"·------------------ 60/80 .886 6.470 . 61-Q17 37°56'59" 118°53'48" ................................ u Hornblende. ______________________ 100/115 1.943 .896 61-Q08 37°53'10" 118°37'30" ------------ u Biotite. ___________________________ 60/80 .355 6.830 61-o26 37°53'10" 118°37'30" ------------ u Hornblende _______________________ 100/115 2.019 .896 61-190 38°56'40" 118°50'10" ------------ u · _____ do _____________________________ 100/115 .976 • 735 61-191 38°43'12" 118°26'45" ------------ u ___ .. do __________ ------------ __ ----_ 100/115 1.663 . 585 61-Q07 38°39'30" 118°31'05" ---------·-- u Biotite. ___________________________ 60/80 . 569 5.880 61-Q18 38°39'30" 118°31'05" ------------ u Hornblende. _____ --_._. ___________ 100/115 1.001 . 512 61-Q22 38°35'15" 118°04"50' ............................... u __ -.do.- __ --- __ ------------------. 100/115 1. 363 .. 551 71-Q02 38°26'17" 118°12'42" ------------ u Biotite. ___________ • _______________ 60/80 .195 6.170 71-Q06 38°26'17" 118°47'02" ------------ u ___ .do ______________________ -~ _____ 60/80 .198 6.860 61-194 38°19'07" 118°37'30" ------------ u Hornblende. ______________________ 100/115 1.002 .411 71-Q22 38°16'20" 118°28'50" ------------ u Biotite. ___________________________ 60/80 .202 8.150 61-196 38°16'20" 118'28°50" ------------ u Hornblende _______________________ 100/150 1.005 .466 61-188 38°11'50" 118°31'15" ------------ u •... do _____________________________ 100/115 1.000 • 560 

71-Q79 34°02'10" 117°33'26" ------------ u Biotite. ____________ -------_-- _____ 60/80 .203 7.420 71-Q73 34°02'10" 117°33'26" ................................. u Hornblende. ______________________ 100/150 . 998 1.190 71-Q75 33°55'20" 117°19'06" ------------ u Biotite. ____ - _____ ----------------- 60/80 .194 7.880 71-Q61 33°55'20" 117°19'06" ----..... -............ u Hornblende---~------------------- 100/115 1.003 . 593 71-Q63 33°54'40" 117°15'12" .............................. u _--.do _____________________________ 100/115 1.002 .688 71-Q81 33°36'12" 117°12'30" ------------ u Biotite. ___________________________ 60/80 .197 7. 780 

71-Q71 33°36'12" 117°12'30" ------------ u Hornblende _______________________ 100/115 .993 .838 71-Q77 33°31'02" 116°42'10" ------------ u Biotite.~ _______________ -- _________ 60/80 .204 7.820 71-Q65 33°31'02" 116°42'10" ------------ u Hornblende. ______________________ 100/150 . 987 .889 

71-083 33°07'15" 117°08'22" ------------ u Biotite. ___________________________ 60/80 .171 7.550 71-Q67 33°07'15" 117°08'22" ------------ u Hornblende _______________________ 100/115 .994 .549 71-Q69 33°05'40" 116°56'40" ------------ u _____ do _____________________________ 100/115 1.003 .671 61-119 36°15'10" 121°32'30'' ----------·- u ..... dO----------------------------- 100/115 1.075 .548 61-117 36°15'10" 121°32'30" ------------ u _____ do _____________________________ 100/115 1.120 .880 MKA-399 38°18'40" 123°04'15" ------------ u _____ do _____________________________ 100/115 2.152 .830 

Ages of South American granitic rocks not shown on plates 1 and 2 

Latitude Longitude Elevation Picked (P) Size Weight 

(N. and 8.) (W.) (ft) or unpicked Mineral (standard (grams) 

(U) mesh) 

67°50' ______ ------ U Biotite _____________ ---- __ ---------------" __ ------------------------------------ ____ _ 67°52' ____________ U Muscovite __________________________________________________________________________ _ 

76°02' ------- _____ U _ ... do ____________ ------------------------------------------------------------------- 70003' __ ----- __ -- _ U _ ___ _ _ __ __ _ .do •..•• _________ -- __ ---------- __ ---_----- ___ --- _____________ ---- ________________ _ 

73°09' ____________ U ____ ---- _ Biotite •• ----_----_--_------- ______ .------------------------------------------------- 70°22' ____________ U ____________ .• do _____ ------_-------------_----------------------------------------------------- 70°02' _______ ----- U ___________ ..• do ________________ ------ ________ -_--------------------.--_---_--_---------------·- 70042' ____________ U ____________ .• do ____________________ • __________________________________________________ • ______ _ 

68°07' U. ___________ .. do ______________ ---------~-_-------------------_--------------------------------- 89032' ____________ U. ___________ .. do ________________________________________ ------_--- __ ---- ________ • ___ --------_._ 

68°28' ____________ U ____________ .. do _____________ ------------_.-------------- __ ---------.----- ____ ----------------

Arat'o 

(percent) 

9 

6 

9 

36 

6 

4 

5 

9 

20 

8 

42 

62 

15 

15 

27 

21 

32 

27 

31 

52 

5 

40 

11 

9 

10 

13 

48 

33 

19 

56 

32 

30 

13 

K(wt 

percent) 

7.24 

8.56 

10.85 

7.66 

6. 72 6.51 

7.08 

6.43 

7.66 

5.24 

6.42 

Age 

(108 yr) 

11( .... .,) 

(percent) 

149.2 .......................... 157.5 .......................... 153.5 ........................... 139.4 .......................... 195.0 ......................... 210.2 -------....... 206.2 ......................... 140.4 .......................... ·89.1 ........................ 93.8 .. !" .................... 

90.2 ......................... 84.3 ........................ 91.9 ....................... 75.4 .......................... 75.3 ....................... 86.1 .......................... 100.5 ............................ 101.9 ... ------......... 94.2 ........................... 95.0 ... ...................... 94.1 ......................... 94.7 ....................... 96.4 ......................... 98.4 .......................... 101.9 ......................... 85.9 ........................... 87.7 .......................... 91.1 ......................... 101.1 ......................... 104.9 

77.2 75.8 ======= === 

92.0 

Ar.~'o 

(percent) 

10 

2 

5 

2 

4 

3 

6 

5 

3 

7 

9 

............................ 

----------

Age 

(106 yr) 

199.0 

183.0 

195.0 

187.0 

204.0 

180.0 

207.0 

213.0 

211.0 

178.0 

180.0 
TABLE 6 35. 

TABLE 6.-Rock name and description of sample locality 

(Latitudes and longitudes given in table 5] 

KANo. 

(unless othenoise 

'ncHcated) Rock name 

477 _________ Trondhjemite of 

Caribou Mountain 

(Davis, 1961). 

LocaUty 

Coffee Creek quadrangle, 

California. 

579 ____ - _ _ _ _ Quartz monzonite of Behind large garage and 

Beer Creek (McKee storage shed immeand Nelson, 1967). diately behind (east of) 

Deep Springs School, 

Soldier Pass quaddrangle, CaliforniaNevada. 

668 ___ ------ Unnamed 

(Christensen, 

1959). 

Along trail in pass 

between Columbine 

Lake and Lost Canyon, 

Kaweah quadrangle, 

California. 

804 _________ Papoose Flat pluton_ Papoose Flat, Inyo 

820 _ _ _ _ _ _ _ _ _ Isabella 

Granodiorite of 

Miller (1931). 

822 _________ Isabella 

Granodiorite 

(

11foliated'.') of 

Miller (1931). 

828_ _ _ _ _ _ _ _ _ Trondhjemite of 

Horseshoe Lake 

(Davis, 1961). 

Mountain, Waucoba 

Mountain quadrangle, 

California. 

Survey Point 3135T, 

near Kern River, 

northwest of Yellowjacket, Kernville 

quadrangle, California. 

SE~SW~ sec. 11, R. 33 

E., T. 25 S., about 72. 

mile east of eastern 

branch of Kern Canyon 

fault, Isabella quadrangle, California. 

From ridge west of 

Forest Peak, Minersville quadrangle, 

California. 

840 ___ -- ____ Granite of Sylvania Highest point on Sylvania 

Mountain. Mountain, 7,998 ft, 

Magruder Mountain 

quadrangle, NevadaCalifornia. 

842 _________ Hornblende diorite Western side of Gold 

Hill, northern part of 

lot 37, Cholame Ranch 

quadrangle, California. 902 ________ _ 

955 ________ _ 

(Hay, 1963). 

Quartz monzonite of 

Beer Creek 

(McKee and 

Nelson, 1967). 

Unnamed (Romey, 

1962). 

1 mile north of Sugarloaf 

Mountain, Soldier 

Pass quadrangle, 

California-Nevada. 

SW~ sec. 35, T. 41 N., 

R. 10 W., Etna 

quadrangle, California. 

956 _____________ _.do _____________ West endof Statue Lake, 

957 ____ - _- _ _ Quartz diorite of 

Deadman Peak 

(Holdaway, 

1963). 

Etna quadrangle, 

California. 

6.36 miles S. 17° E. of 

northwest corner of 

Coffee Creek quadrangle, California. 

TABLE 6.-Rock name and description of sample locality-Con 

KANo. 

(unless othenoise 

indicated) Rock name 

1432 ________ Elephant Butte 

pluton (Gromme, 

1963). 

1433 _____________ do ____________ _ 

1436 __________ Bucks pluton 

( Gromme, 1963). 

1437 _____________ do ____________ _ 

1438 ________ Merrimac pluton 

( Gromme, 1963). 

1439 _____________ do ____________ _ 

1440 ________ Cresta pluton 

( Gromme, 1963). 

1441 _____________ do ____________ _ 

1442 ________ Bucks pluton 

( Gromme, 1963). 

1449 _____________ do ____________ _ 

1501 ________ Unnamed _________ _ 

1502 _____________ do _____________ _ 

1503 _____________ do ____________ _ 

Locality 

1,000 ft south of Rock 

Creek in canyon of 

North Fork of Featber 

River, Pulga quadrangle, California. 

Do. 

72 mile north of Workman's Bar in canyon 

of North Fork of 

Feather River, Pulga 

quadrangle, California. 

Do. 

1 mile southwest of 

Merrimac near Coon 

Creek, Pulga quadrangle, California. 

Do. 

U mile north of Cresta 

powerhouse, in canyon 

of North Fork of 

Feather River, Pulga 

quadrangle, Califorina. 

Do. 

At Workman's Bar, in 

canyon of North Fork 

of Feather River, 

Pulga quadrangle, 

California. 

Do. 

Deans Ridge, Eagle Lake, 

at 5,600 ft on dirt road, 

Fredonyer Peak quadrangle, California. 

Northeast slope of Deans 

.Ridge, at 5,350 ft on 

road, Fredonyer Peak 

quadrangle, California. 

On Janesville Grade, at 

ridge line of secondary 

ridge immediately 

east of main volcaniccapped ridge, Susanville quaqrangle, 

California. 

1504 _____________ do _____________ Head of Janesville 

Grade, at intersection 

of Thompson Creek 

Road and road to 

Thompson Peak lookout,· Kettle Rock 

quadrangle, California. 

1506 _____________ do _____________ X mile west of Forest 

Service Road 27N03, 

on Road 27N12, 

Plumas National 

Forest, Milford quadrangle, California. 
36 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KA. No. 

(unless otherwise 

indicated) Rock name Locality 

1508 ________ Unnamed ____________ Beckwourth Pass, from 

Western Pacific Railroad tunnel, Chilcoot 

quadrangle, California. 

1509 _____________ do _____________ 0~ Forest Service road 

27N02 at road intersection in SWX sec. 

3, T. 23 N., R. 14 E., 

Portola quadrangle, 

California. 

1510 _____________ do _____________ Yuba Pass, California 

State Highway 49, Yz 

mile southwest of 

pass on dirt road, 

Sierraville quadrangle, 

.California. 

151L ____________ do ______________ 1.1 miles east of Yuba 

Pass on· California 

State Highway 49, 

Sierraville quadrangle, 

California. 

1512 _____________ do _____________ BM 6680 on U.S. Highway 40, just east of 

Donner Summit, Donner Pass quadrangle, 

California. 

1514 _____________ do _____________ Base of west wall of 

Angora Peak, perpendicular to stream at 

first trail crossing on 

Lake of Woods trail, 

Fallen Leaf Lake 

quadrangle, California. 

1516_--------- ___ do _____________ Daggett Pass, Nevada 

State Highway 19, 

Freel Peak quadrangle, 

California-Nevada. 

1517 _- ___ -- ______ do _____________ At Daggett Creek on 

Nevada State Highway 

19, Freel Peak quadrangle, CaliforniaNevada. 

1518 _____________ do _____________ At 7,500 ft in Horsethief 

1519 _____________ do ____________ _ 

1520 _____________ do ____________ _ 

1521 ________ Carson Pass Tonalite 

of Parker (1961). 

Canyon, Freel Peak 

quadrangle, CaliforniaNevada. 

On west side of Carson 

Pass at 7,250 ft on 

California State Highway 88, Silver Lake 

quadrangle, California. 

East of Carson Spur at 

7,720 ft on California 

State Highway 88, 

Silver Lake quadrangle, 

California. 

Summit, Carson pass on 

California Highway 

88, Markleeville 

quadrangle, California. 

KA. No. 

(unless otherwise 

indicat.ed) Rock name 

1523 _ _ _ _ _ _ _ _ Stanislaus Meadow 

Adamellite of 

Parker (1961). 

1524 ________ Unnamed _________ _ 

1525 _ _ _ _ _ _ _ _ Half Dome Quartz 

Monzonite 

(Calkins, 1930). 

1526 ________ Transition zone between Half Dome 

Quartz Monzonite 

and Cathedral 

Peak Granite 

(Calkins, 1930). 

1527 _ _ _ _ _ _ _ _ Cathedral Peak 

Granite (Calkins, 

1930). 

1528 _____________ do ____________ _ 

1530 _____________ do ____________ _ 

1531 _____________ do ____________ _ 

1532 ________ Half Dome Quartz 

Monzonite 

(Calkins, 1930). 

1533_ _ _ _ _ _ _ _ Cathedral Peak 

Granite (Calkins, 

1930). 

1534 ________ Quartz monzonite of 

Topaz Lake 

(Cathedral Peak 

type) (Curtis, 

1951). 

1535 ________ Quartz monzonite of 

Topaz Lake 

(Cathedral Peak 

type) (Slemmons, 

1953). 

Locality 

At 7,500 ft on California 

State Highway 4, east 

of Lake Alpine, 

Dardanelles Cone 

quadrangle, California. 

At 7,600 ft on California 

State Highway 4, east 

of Ebbetts Pass, just 

east of Silver Creek, 

Markleeville quadrangle, California. 

May Lake trailhead, 

Retch Hetchy quadrangle, California. 

At 8,800 ft on southeast 

flank of Polly Dome, 

Tuolumne Meadows 

quadrangle, California. 

At 8,800 ft on east side 

of Polly Dome, 

Tuolumne Meadows 

quadrangle, California. 

At 8,800 ft on north nose 

of Fairview Dome, 

Tuolumne Meadows 

quadrangle, California. 

At 9,000 ft on Echo 

Creek, Tuolumne 

Meadows quadrangle, 

California. 

At 9,000 ft on shore of 

Babcock Lake, 

Tuolumne Meadows 

quadrangle, California. 

At 8,800 ft on John 

Muir Trail in Lyell 

Fork Canyon, 

Tuolumne Meadows 

quadrangle, California. 

At 8,800 ft on John 

Muir Trail in Lyell 

Fork Canyon, 

Tuolumne Meadows 

quadrangle, California. 

At 6,640 ft on Wolf 

Creek, Topaz 

Lake quadrangle, 

California. 

Head of Clark Fork of 

Stanislaus River at 

10,200 ft, Sonora Pass 

quadrangle, California. 

1536 __________ 7 

__ do _____________ At 7,450 ft on west side 

of The Iceberg, Sonora 

Pass quadrangle, 

California. 
TABLE 6 37 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KA. No. 

(1mZcss otherwise 

inllicated) Rock name 

1537 ________ Quartz monzonite of 

Topaz Lake 

(Cathedral Peak 

type) (Slemmons, 

1953). 

1538_ _ _ _ _ _ _ _ Granodiorite west of 

quartz monzonite 

of Topaz Lake 

(Slemmons, 1953). 1539 _____________ do ____________ _ 

1540 ________ Unnamed _________ _ 

1541 _____________ do ____________ _ 

1542 _ _ _ _ _ _ _ _ Granodiorite west 

of quartz monzonite of Topaz 

Lake (Slemmons, 

1953). 

1543 _ _ _ _ _ _ _ _ Quartz monzonite of 

Topaz Lake 

(Cathedral Peak 

type) (Slemmons, 

1953). 1545 _____________ do ____________ _ 

1546 _____________ do ____________ _ 

1547 _____________ do ____________ _ 

1548 _____________ do ____________ _ 

1549 _____________ do ____________ _ 

1550 _____________ do ____________ _ 

Locality 

At BM 5831 on California State Highway 108, 

Dardanelles Cone 

quadrangle, California. 

At Clark Fork Bridge, 

Dardanelles Cone 

quadrangle, California. 

At Niagara Creek on 

California State Highway 108, Dardanelles 

Cone quadrangle, 

California. 

% mile north of Cascade 

Creek at 6,080 ft on 

California State Highway 108, Dardanelles 

Cone quadrangle, 

California. 

On California State 

Highway 108 at 

roadcut west of 

Strawberry Resort at 

5, 250 ft, Long Barn 

quadrangle, California. 

At 7,650 ft between 

Fence and Cloudburst 

Creeks, Dardanelles 

Cone quadrangle, 

California. 

At 7,600 ft on west side 

of Cloudburst Creek, 

Dardanelles Cone 

quadrangle, California. 

On· California State 

Highway 108 at bridge 

crossing of Kennedy 

Creek, Sonora Pass 

quadrangle, California. 

At 7,500 ft in Woods 

Gulch, Dardanelles 

Cone quadrangle, 

California. 

At 7,400 ft in Woods 

Gulch, Dardanelles 

Cone quadrangle, 

California. 

At 7,600 ft along East 

Fork of Carson River, 

Sonora Pass quadrangle, California. 

At 7,500 ft on Boulder 

Creek, Sonora Pass 

quadrangle, California. 

At 10,040 ft at head of 

Silver Creek, Sonora 

Pass quadrangle, 

California. 

KA. No. 

( unZess otherwise 

indicated) Rock name 

155L _______ Quartz monzonite of 

Mono Recesses 

(Cathedral Peak 

type) (Sherlock 

and Hamilton, 

1958). 1552 _____________ do ____________ _ 

1553 _____________ do ____________ _ 

1554 _ _ _ _ _ _ _ _ Quartz monzonite of 

Lagille Peak 

(Cathedral Peak 

type). 

1555 _____________ do ____________ _ 

1556_ _ _ _ _ _ _ _ Cathedral Peak type_ 

1559 _ _ _ _ _ _ _ _ Quartz monzonite of 

Mono Recesses 

(Cathedral Peak 

type). 

1560 _____________ do ____________ _ 

156l _____________ do ____________ _ 

1562_ _ _ _ _ _ _ _ Isabella Granodiorite and its facies 

(Miller, 1931; 

Miller and Webb, 

1940). 1563 _____________ do ____________ _ 

1564 _____________ do ____________ _ 

1565 _ _ _ _ _ _ _ _ Unnamed _________ _ 

Locality 

At 11,500 ft on ridge 

west of Lower Hopkins 

Lake, Mount Abbot 

quadrangle, California. 

At 9,000 ft on Mono 

Creek, Mount Abbot 

quadrangle, California. 

At 11,500 ft on west side 

of Mono Pass, Mount 

Abbot quadrangle, 

California. 

At 11,500 ft on north 

shoulder of Shakespeare Peak, Mount 

Goddard quadrangle, 

California. 

At 8,080 ft on Middle 

Fork of Kings River 

above junction with 

Palisade Creek, Mount 

Goddard quadrangle, 

California. 

At 11,500 ft along trail 

on west side Kearsarge 

Pass, Mount Pinchot 

quadrangle, California. 

Top of hill 924 7, northnorthwest of Devil's 

Post pile National 

Monument, Devil's 

Postpile quadrangle, 

California. 

At 9,000 ft in hill 9247, 

Devil's Postpile quadrangle, California. 

At 11,500 ft in Granite 

Park, Mount Abbott 

quadrangle, California. 

At 2,800 ft in SWU sec. 

32, T. 24 S., R. 33 E., 

Kernville 30 minute 

· quadrangle, California. 

At 4,000 ft in center sec. 

35, T. 22 S., R. 32 E., 

Kernville 30 minute 

quadrangle, California. 

At 6,200 ft on road, 

south side of Horse 

Canyon, Camp Nelson 

quadrangle, California. 

1.4 miles south of road 

crossing of Boulder 

Creek on California 

State Highway 190, 

on west-facing side of 

ridge, Camp Nelson 

quadrangle, California. 
38 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KA. No. 

(unless otherwise 

indicated) Rock name 

1566- ________ Unnamed_----------

1568 _____________ do ____________ _ 

1569_-- __________ do _____________ _ 

1570------~------do ____________ _ 

1571 _____________ do ____________ _ 

1572 _____________ do ____________ _ 

1573 _____________ do ____________ _ 

1574-------------dO----~--------

1575 _____________ do ____________ _ 

1576-------------do ____________ _ 

1571-------------do ____________ _ 

Locality 

At Mcintyre Creek on 

California State 

Highway 190, Camp 

NelSon quadrangle, 

California. 

On California State 

Highway 190, just west 

of Coffee Creek Picnic 

Ground, Camp Nelson 

quadrangle, California. 

In most westerly X mile 

of granite outcrops 

west-northwest of 

Woody on WoodyDelano· Road, 6.4 

miles west of Woody, 

Woody quadrangle, 

California. 

1.2 miles northeast of 

Woody on WoodyGreenhorn Summit 

road, Woody quadrangle, 

California. 

1.4 miles west of Lynns 

Valley on WoodyGreenhorn s·ummit . 

road, Woody quadrangle, California. 

3.65 miles east of Glennvllle on Woody-Greenhorn Summit road, 

Tobias Peak 30 minute 

quadrangle, California. 

3.50 miles east of west 

boundary of Sequoia 

National Forest, just 

west of Cedar Creek 

on highway, Tobias 

Peak quadrangle, 

California. 

1.25 miles east of Greenhorn Summit at 5,780 

ft on highway, Tobias 

Peak 30 minute quadrangle, California. 

At 3,750 ft on highway 

5.6 miles east of 

Greenhorn Summit, 

Kernville 30 minute 

quadrangle, California. 

French Gulch, at Kern 

County Camp No. 3 

on Kernville-Isabella 

road, Isabella quadrangle, California. 

On California State 

Highway 178, 3.0 

miles east of intersection with KernvilleIsabella road, Isabella 

quadrangle, California. 

KA. No. 

(unless otherwise 

indicated) Rock name 

1578 _________ Unnamed __________ _ 

1579 _____________ do ____________ _ 

1580 _____ : _______ do ____________ _ 

1581 _____________ do ____________ _ 

1582 _____________ do ____________ _ 

1583_ _ _ _ _ _ _ _ Cathedral Peak type_ 

1584 ________ Whitney pluton ____ _ 

1585 _____________ do ____________ _ 

1586 _________ : ___ do ____________ _ 

1587 _____________ do ____________ _ 

1588------~------do ____________ _ 

1589 _____________ do ____________ _ 

1590---~---------do ____________ _ 

Locality 

1.2 miles west of Weldon 

on California State 

Highway 178, Isabella 

quadrangle, California. 

1.2 miles east of Onyx 

on California State 

Highway 178, Onyx 

quadrangle, California. 

At 2,900 ft on California 

State Highway 178, 

on west end of ridge 

across creek from 

Bloomfield Ranch, 

Onyx quadrangle, 

California. 

At.3,450 ft on California 

State Highway 178, 

approximately 0.55 

miles west of intersection of Canebrake and 

Spanish Needle Creeks, 

Lamont Peak quadrangle, California. 

At 4,410 ft on California 

State Highway 178, 

just west of intersection 

of Canebrake and 

Three Pines Canyon 

Creeks, Onyx quadrangle, California. 

Alabama Hills, on road 

to Whitney Portal, 

Lone Pine quadrangle. 

California. 

At Whitney Portal, 

8,480 ft, Lone Pine 

quadrangle, California. 

At 9,500 ft on Olancha 

Peak, Olancha quadrangle, California. 

At 9,680 ft on Golden 

Trout Creek, Kern 

Peak quadrangle, 

California. 

At 9,280 ft on Wallace 

Creek Trail, Mount 

Whitney quadranglE', 

California. 

At 11,530 ft on west 

side of Trailcrest 

along trail, Mount 

Whitney quadrangle. 

California. 

At 11,500 ft along 

Tyndall Creek, Mount 

Whitney quadrangle, 

California. 

At Trailcrest, 13,777 ft, 

Mount Whitney quadrangle, California. 
TABLE 6 39 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KANo. 

(unZess otherwise 

'ncUcatea) Rock name 

1591 ________ lJnnamed _________ _ 

1592 _____________ do ____________ _ 

1593_ _ _ _ _ _ _ _ Cathedral Peak 

Granite. 

1594 _____________ do ____________ _ 

1595 _____________ do ____________ _ 

1596 _____________ do ____________ _ 

1597 _____________ do ____________ _ 

1598 _____________ do ____________ _ 

1599 _____________ do ____________ _ 

1600 _____ - _- Quartz monzonite of 

Lagille Peake 

(Cathedral Peak 

type). 

1601 ____ - - - - Lamarck Granodiorite. 

1602 ________ lJnnamed _________ _ 

1603 _____________ do ____________ _ 

1604 _____________ do ____________ _ 

LocaU.ty 

At 11,600 ft on east side 

of Trailcrest along trail, 

Mount Whitney quadrangle, California. 

At 7,680 ft on Whitney 

Portal Road, Lone 

Pine quadrangle, 

California. 

40 ft below summit of 

Qathedral Peak, 

Tuolumne Meadows 

quadrangle, California. 

At 8,700 ft on east flank 

of Lembert Dome, 

Tuolumne Meadows 

quadrangle, California. 

At 11,000 ft on high point 

of ridge west of Little 

Slide C Canyon, Matterhorn Peak quadrangle, California. 

At 9,200 ft west-northwest from KA 1595 on 

small tributary stream 

entering Robinson 

Creek from southeast, 

Matterhorn Peak 

quadrangle, California. 

At 7,950 ft on Twin LakeBarney Lake trail, 

Matterhorn Peak 

quadrangle, California. 

At 7,300 ft on Barney Lake 

trail, Matterhorn Peak 

quadrangle, California. 

At 9,000 ft on Kirkwood 

Creek, Tower Peak 

quadrangle California. 

At 11,500 ft on west side 

of Hermit Ridge, 

McGee Lakes basin, 

Mount Goddard 

quadrangle, California. 

At 12,880 ft from 

Lamarck Col, Mount 

Goddard quadrangle, 

California. 

At 2,400 ft on Mineral 

King road, Mineral 

King quadrangle, 

California. 

At 3,050 ft on Mineral 

King road, Mineral 

King quadrangle, 

California. 

At 3,900 ft on Mineral 

King road, Mineral 

King quadrangle, 

California. 

KANo. 

( unZess otherwise 

indicated) Rock name 

1605 ________ Unnamed _________ --

1606 _____________ do ____________ _ 

1607 _____________ do ____________ _ 

1608 ______________ do ____________ _ 

1609 _____________ do ____________ _ 

1610 _____________ do-~-----------

1621 _____________ do ____________ _ 

1624 _____________ do ____________ _ 

1626 _____________ do ____________ _ 

LocaU.ty 

At 4,050 ft on Mineral 

King road, Mineral 

King quadrangle, 

California. 

At 4,800 ft on Mineral 

King road, Mineral 

King quadrangle, 

California. 

At 7,000 ft on Mineral 

King road, 1 mile east 

of Silver City, Mineral 

King quadrangle, 

California. 

At top of Sawtooth Peak, 

12,340 ft, Kaweah 

quadrangle, California. 

At 10,800 ft, head of Lost 

Canyon, east of Columbine Lake (virtually same locality as 

KA 1608), Kaweah 

quadrangle, California. 

At 11,600 ft in Sawtooth 

Pass, Kaweah quadrangle, California. 

8.2 miles west of 

Tehachapi Railroad 

Station on California 

State Highway 58 

(lJ.S. Highway 466) 

at 2,700 ft, Tehachapi 

quadrangle, California. 

1.0 mile east of Mi-wuk 

Village on California 

State Highway 108, 

Long Bam quadrangle, 

California. 

At east end of business 

district of Three 

Rivers on California 

State Highway 198. 

1627 _____________ do _____________ At southeast end of Bass 

Lake from borrow pit 

for dam, Bass Lake 

quadrangle, California. 

1628 _____ ._ _______ do _____________ 0.8 mile west of west 

end of Oakhurst 

bridge on California 

State Highway 41, 

Bass Lake quadrangle, 

California. 

1629 ______ .: ______ do ____ :._ ________ 1.05 miles west of Horse 

Creek Road turnoff, 

4.75 miles east of 

Woodlake turnoff on 

California State 

Highway 198. 
40 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITIDC COMPLEXES IN CALIFORNIA AND NEVADA 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KA. No. 

(unless otherwise 

indicated) Rock name 

1630 _________ Unnamed __________ _ 

1631 _____________ do ____________ _ 

1632 _____________ do ____________ _ 

1633 _____________ do ____________ _ 

1634 _____________ do ____________ _ 

1635 _____________ do ____________ _ 

1636 _____________ do ____________ _ 

1663_ _ _ _ _ _ _ _ Granodiorite of The 

Gateway (Calkins, 1930). 

1664 ________ Unnamed _________ _ 

Locality 

0.8 mile northeast of 

hill 1560, approximately 12.5 miles S. 

81° E. of Visalia, 

Visalia quadrangle, 

California. 

At 2,600 ft on Grapevine, U.S. Highway 99. 

2. 95 miles east of Sonora 

city limits, 1.0 mile 

east of Tuolumne City 

turnoff, on California 

State Highway 108, 

Sonora quadrangle 

California. 

At Big Meadows Campground on California 

State Highway 4, Big 

Meadow quadrangle, 

California. 

0.65 mile west of Soulsbyville turnoff, 2.6 

miles east of Standard 

turnoff, on California 

State Highway 108, 

Sonora quadrangle, 

California. 

0.1 mile west of Dorrington on California State 

Highway 4 at 4,800 ft, 

Blue Mount quadrangle, California. 

0.5 mile west of Poison 

Spring at 6,560 ft on 

California State Highway 4, Big Meadow 

quadrangle, California. 

At west park boundary 

of Yosemite National 

Park on California 

State Highway 140. 

0.8 mile east of Avery at 

3,500 ft on California 

State Highway 4, 

Columbia quadrangle, 

California. 

1665 _____________ do _____________ 1.9 miles northwest of 

Wawona on California 

State Highway 41 at 

approximately 4,200 ft, 

Yosemite National 

Park. 

1666 _____________ do _____________ 5.2 miles east of Road 

208, 7.3 miles east of 

California State Highway 145, on California 

State Highway 41, 

at 1,150 ft. 

KA. No. 

(unless otherwise 

indicated) Rock name 

1678 _________ Unnamed __________ _ 

1679 _____________ do ____________ _ 

1683 _____________ do ____________ _ 

1697 _____________ do ____________ _ 

1698 _____________ do ____________ _ 

1699 _____________ do ____________ _ 

1700 _____________ do ____________ _ 

1701 _____________ do ____________ _ 

1702 _____________ do ____________ _ 

DKA 1028 ___ Granodiorite of 

Mono Dome 

(Kistler, 1966a). 

DKA 1029 ________ do ____________ _ 

Locality 

1.5 miles west of Pyramid 

Campground on U.S. 

Highway 50, Fallen 

Leaf Lake quadrangle, 

California. 

Approximately % mile 

east of hairpin turn, at 

90° turn, west of Camp 

Sacramento on U.S. 

Highway 50, Fallen 

Leaf Lake quadrangle, 

California. 

0.8 mile west of Silver 

Fork at 3,880 ft on 

U.S. Highway 50, 

Robbs Peak quadrangle, California. 

At 6,020 ft on west side 

of U.S. Highway 395 

along West Walker 

River at north end of 

Shingle Mill Flat. 

4.5 miles west of Silver 

Fork at 3,500 ft on 

U.S. Highway 50, 

Robbs Peak quadrangle, California. 

1.6 miles west of Whitehall on U.S. Highway 

50, Robbs Peak quadrangle, California. 

4.8 miles west of Whitehall, 0.5 mile east of 

Bridalveil picnic area, 

on U.S. Highway 50, 

Robbs Peak quadrangle, California. 

Where California State 

Highway 49 crosses 

Middle Fork Yuba 

River, Camptonville 

quadrangle, California. 

1.3 miles west of Chapman Creek Campground on California 

State Highway 49, 

Sierra City quadrangle, 

California. 

California State Highway 

120, 1 mile north of 

Ellery Lake, Mono 

Craters quadrangle, 

California. 

California State Highway 

120, 1 mile north of 

Ellery Lake, Mono 

Craters quadrangle, 

California. 
TABLE 6 41 

TABLE 6.-Rock name and description of sample locality-Con. 

J(A No. 

(unZcss othm"'lvisc 

incticatell) Bock name 

MKA 409- _ _ _ Granodiorite of 

Mono Dome 

(Kistler, 1966a). 

MKA 4L ____ Quartz monzonite of 

Ellery Lake 

(Kistler 1966a). 

DKA 103L __ Granodiorite of 

Mono Dome 

(Kistler, 1966a). 

DKA 1032 ________ do __ ----- _____ _ 

DKA 1030 ________ do ____________ _ 

MKA410 _________ do ____________ _ 

Locality 

California State Highway 

120, 1 mile north of 

. Ellery Lake, Mono 

Craters quadrangle, 

California. 

Hill 11582 on Dana 

Plateau, Mono Craters 

quadrangle, California. 

California State Highway 

120, 1.2 miles north 

of Ellery Lake, Mono 

Craters quadrangle, 

California. 

California State Highway 

120, 1.2 miles north 

of Ellery Lake, Mono 

Craters quadrangle, 

California. 

Elevation 11,100 ft, 

1.2 miles southeast of 

Lee Vining Peak, Mono 

Craters quadrangle, 

California. 

Elevation 11,100 ft, 1.2 

miles southeast of Lee 

Vining Peak, Mono 

Craters quadrangle, 

California. 

BKA 558 _________ do _____________ BM 8615, California 

MKA 42_ _ _ _ Wheeler Crest 

Quartz Monzonite 

(Kistler, 1966a). 

BKA 488 ____ Quartz monzonite of 

Aeolian Buttes 

(Kistler, 1966a). 61-192 ___________ do ____________ _ 

BKA 487 _ _ _ _ Wheeler Crest 

Quartz Monzonite 

(Kistler, 1966a). 

State Highway 120, 

Mono Craters quadrangle, California. 

Hill 9962, 2 miles south 

of Mono Dome, Mono 

Craters quadrangle, 

California. 

Hill 7451, Aeolian 

Buttes, Mono Craters 

quadrangle, California. 

Hill 7451, Aeolian 

Buttes, Mono Craters 

quadrangle, California. 

Roadcut, just northeast, 

of town of June Lake, 

Mono Craters quadrangle, California. 

MKA 458 ________ do _____________ Roadcut, just northeast 

BKA 556_ _ _ _ Granodiorite of 

Kuna Crest 

(Kistler, 1966a). 

BKA 557 ____ Granodiorite of 

Rush Creek 

(Kistler, 1966a). 

61-04L _____ Unnamed _________ _ 

of town of June Lake, 

Mono Craters quadrangle, California. 

Elevation 11,600 ft, 

0.25 mile north of 

Donohue Peak, Mono 

Craters quadrangle, 

California. 

0.2 mile west of Billy 

Lake, Mono Craters 

quadrangle, California. 

Quarry, 1 mile south of 

Knowles, Raymond 

quadrangle, California. 

TABLE 6.-Rock name and description of sample locality-Con. 

KANo. 

(unless otherwise 

indicated) Rock name 

61-042 ______ Unnamed __________ _ 

61-001 ______ Tungsten Hills 

Quartz Monzonite 

(Bateman, 1961). 

61-020 ___________ do ____________ _ 

MKA 51_ ___ Unnamed _________ _ 

61-047 _ ------ Santa. Rita Flat 

pluton of the 

Tinemaha Granodiorite (Ross, 

1965). 

61-043 _ _ _ _ _ _ Quartz monzonite of 

Piute Monument 

(Ross, 1965). 

61-045 ______ Tinemaha Granodiorite (Ross, 

1965). 

61-044 ______ Pat Keys pluton 

(Ross, 1965). 61-019 ______ Unnamed _________ _ 

61-025 ___________ do ____________ _ 

61-166 ___________ do _____________ _ 

61-003 ___________ do ____________ _ 

Locality 

Quarry, 1 mile south of 

Knowles, Raymond 

quadrangle, California . 

Elevation 10,000 ft, 

North Fork, Piute 

Creek, Mount Abbot 

quadrangle, California. 

Elevation 10,000 ft, North 

Fork, Pitite Creek, 

Mount Abbot quadrangle, California. 

Burgess mine, New York 

Butte quadrangle, 

California. 

Independence quadrangle, California .. 

Independence quadrangle, California. 

Independence quadrangle, California. 

Waucoba Mountain 

quadrangle, California. 

Comanche Gulch, Blind 

Spring Hill, Benton 

quadrangle, California. 

Comanche Gulch, Blind 

Spring Hill, Bent~n 

quadrangle, California. 

Comanche Gulch, Blind 

Spring Hill, Benton 

quadrangle, California. 

3 miles south of Cowtrack 

Mountain, Cowtrack 

Mountain quadrangle, 

California. 

61-017 ___________ do _____________ 2 miles southwest of 

Cowtrack Mountain, 

Cowtrack Mountain 

quadrangle, California. 

61-008 ___________ do _____________ California State Highway 

120, 1.5 miles south 

of River Spring Lakes, 

Glass Mountain quadrangle, California. 

61-026 ___________ do _____________ California State Highway 

120, 1.5 miles south 

of River Spring Lakes, 

Glass Mountain quadrangle, California. 

61-190 ___________ do _____________ 2 miles west of Schurz, 

Nev., north end of 

W assuk Range. 61-19l_ __________ do _____________ Valley between Gillis and 

Gabbs Valley Ranges, 

Nev., 1 mile east of 

Ryan Canyon Road. 
42 CHRONOLOGY OF EMPLACEMENT OF MESOZOIC BATHOLITHIC COMPLEXES IN CALIFORNIA AND NEVADA 

TABLE 6.-Rock name and description of sample locality-Con. TABLE 6.-Rock name and description of sample locality-Con. 

KA.No. 

( unZess otherwise 

indicated) Rock name 

61-007 ___ ----Unnamed ___ --------

61-018 ___________ do ____________ _ 

61-022 ___________ do ____________ _ 

71-002 ___________ do ____________ _ 

71-006 ___________ do ____________ _ 

61-194 ___________ do ____________ _ 

71-022 ___________ do ____________ _ 

61-196 ___________ do ____________ _ 

61-188 ___________ do ____________ _ 

71-079 ________ Granite of Rubidoux Mountain 

(Larsen, 1948). 71-073 ___________ do ____________ _ 

71-083_ _ _ _ _ _ San Marcos Gabbro 

(Larsen, 1948) . 

71-067 ___________ do ____________ _ 

71-069 ______ Green Valley 

Tonalite. 

61-119 __ - ___ Biotite hornblende 

gabbro (Compton, 

1966). 

Locality 

At crest of Gillis Rangtl, 

Nev., on Ryan Canyon Road. 

At crest of Gillis Range, 

Nev., on Ryan Canyon Road. 

Just east of Nevada 

State Highway 23 in 

Gabbs Valley Range. 

In Garfield Hills, due 

south of Luning, Nev. 

On Bodie-Lucky Boy 

Road, due south of 

Cory Peak, Wassuk 

Range, Nev. 

Mouth of Powell Canyon, 

W assuk Range, Nev. 

On road from Hawthorne, 

Nev., to Huntoon 

Valley, Nev., north 

side of Excelsior 

Mountains. 

On road from Hawthorne, Nev., to 

Huntoon Valley, Nev., 

north side of Excelsior 

Mountains. 

Oii. road from Hawthorne, 

Nev., to Huntoon 

Valley, Nev., at north 

end of Huntoon Valley. 

Mount Rubidoux, Riverside West, 7.5-minute 

quadrangle, California. 

Mount Rubidoux, Riverside West, 7 .5-minute 

quadrangle, California. 

Twin Oaks Valley Road, 

quarry in Gopher 

Canyon, San Marcos, 

7.5-minute quadrangle, 

California. 

Twin Oaks Valley Road, 

quarry in Gopher 

Canyon, San Marcos 

7.5-minute quadrangle, 

California. 

California State Highway 

78, 1 :inile east of San 

Pasqua! Battlefield 

State Historical Monument, San Pasqua! 7.5-

minute quadrangle, 

California. 

Hornblendite in Arroyo 

Seco, ~ mile northnorthwest of confluence 

with Santa Lucia 

Creek, Junipero Serra 

quadrangle, California. 

KA.No. 

( unZess otherwise 

indicated) Rock name 

61-117 _ _ _ _ _ _ Biotite hornblende 

gabbro (Compton, 

1966). 

MKA 399 ____ Granodiorite _______ _ 

591 _________ lJnnamed _________ _ 

71-075 ______ Bonsall Tonalite 

(Larsen, 1948) . 

71-061-----------do ____________ _ 

71-063- _ _ _ _ _ Lakeview Mountain 

Tonalite (Larsen, 

1948). 

71-08L _____ Woodson Mountain 

Granodiorite 

(Larsen, 1948) . 

71-071-----------dO-------------

71-077 _ _ _ _ _ _ Sphene-rich tonalite_ 

71-065 ___________ do ____________ _ 

620_ _ _ _ _ _ _ _ _ Muscovite from 

cassiterite vein. 

634_ _ _ _ _ _ _ _ _ Granite ___________ _ 

1466 ________ Gneiss ____________ _ 

1158 ________ Small stock, intrudes 

Mitu Group of 

Middle to Late 

Permian age. 

LocaU.ty 

Northwest end of main 

Junipero Serra Pluton, 

Junipero Serra quadrangle, California. 

Bodega Head, Sonoma 

County, Calif. 

Mururata-Tasquesi, 

Bolivia. 

Val Verdi Tunnel, Cajalco 

Road, Steele Peak, 

7.5-minute quadrangle, 

California. 

Val Verdi Tunnel, Caj alco 

Road, Steele Peak, 

7.5-minute quadrangle, 

California. 

Nuevo Road, 2 miles 

west of Nuevo, Perris 

7.5-minute quadrangle, 

California. 

lJ.S. Highway 395, near 

intersection with road 

to Rainbow, Temecula 

7.5-minute quadrangle, 

California. 

lJ.S. Highway 395, near 

intersection with road 

to Rainbow, Temecula 

7.5-minute quadrangle, 

California. 

Near Tool Box Spring, 

Thomas Mountain, 

Idyllwild quadrangle, 

California. 

Near Tool Box Spring, 

Thomas Mountain, 

Idyllwild quadrangle, 

California. 

Chojilla, lJnduavi, 

Bolivia. 

Carhuamayo, Peru. 

Cerro Machani, Peru. 

Ocona, Peru. 

1159 __ ------ Syenite, cuts Mitu Oscuyo-Ayapata, Peru. 

Group. 

1145_ _ _ _ _ _ _ _ Cumbre de Achasiri Cumbre de 'Achasirigranite ( 60 km X Coasa, Peru. 

15 km), intrudes 

Pennsylvanian 

and older rocks. 

1155_--- __ -:.. Diorite_____________ Caiion de Marcapata, 

Peru. 

1454_.:. _____ _ 

1374 _______ _ 

615 ________ _ 

Granite, intrudes 

Devonian sedimentary rocks. 

Gneiss __________ ---

Sorata batholith ____ _ 

H. Potosi batholith, 

Bolivia. 

Jones, Guatemala. 

Candelaria, Cooco, 

Bolivia. 

U.S. GOVERNMENT PRJNnNG omCE: 1969 0-359-835