Lead-Alpha Age 

Determinations of 

Accessory Minerals of 

Igneous Rocks (1953-1957)

GEOLOGICAL SURVEY BULLETIN 1097-B

This report concerns work done in part 

on behalf of the U.S. Atomic Energy 

Commission and is published with the 

permission of the Commission

Lead-Alpha Age 

Determinations of 

Accessory Minerals of 

Igneous Rocks (1953-1957)

By HOWARD W. JAFFE, DAVID GOTTFRIED, CLAUDE L. WARING 

and HELEN W. WORTHING

STUDIES IN GEOCHRONOLOGY

GEOLOGICAL SURVEY BULLETIN 1097-B

This report concerns work done in part 

on behalf of the U.S. Atomic Energy 

Commission and is published with the 

permission of the Commission

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

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

Washington 25, D.C. - Price 30 cents (paper cover)
CONTENTS

Page

Abstract _____-_-_-_____-__-_________-___________-____-___..-_-_-__ 65

Introduction. _ ____________________________________________________ 65

Acknowledgments. ______--_-______-_-________-_----____-__-___---.. 66

Nature of the descriptive and experimental data_____________________ 67

Method of calculation of the age_--__-_--__--_-------_--_--_--_- 67

Reproducibility of the age determination.________________________ 68

Arrangement of the data in the tabulation____________________--__ 68

Lead-alpha age determinations of accessory minerals.__________________ 69

Geographic index of localities.______________________________________ 140

Literature cited.__________________________________________________ 145

ni

STUDIES IN GEOCHRONOLOGY

LEAD-ALPHA AGE DETERMINATIONS OF ACCESSOR? 

MINERALS OF IGNEOUS ROCKS (1953-1957)

By HOWARD W. JAFFE, DAVID GOTTFRIED, CLAUDE L. WARING, 

and HELEN W. WORTHING

ABSTRACT

The U.S. Geological Survey completed lead-alpha age determinations of 

accessory minerals from about 400 rocks between July 1953 and January 1957. 

All the ages and the experimental data, equations, and constants from which 

they were calculated are given in tabular form. A citation of the most probable 

geologic age of each rock is included for comparison with the measured age. 

The tabulation is followed by a geographic index of sample localities.

INTRODUCTION

Publication of the original report on the method of determining 

the age of igneous rocks from the lead-alpha ratios of their accessory 

minerals (Larsen and others, 1952) aroused considerable interest in 

the application of the method to the solution of geologic problems. 

Larsen has received numerous requests for age determination from 

geologists engaged in field mapping of areas where the age of intrusive 

rocks could not be established from field evidence because of poor 

paleontologic and stratigraphic control.

In July of 1953, the U.S. Geological Survey established a project 

to fill the numerous requests received for lead-alpha age determinations. Since then, determinations have been completed on accessory 

minerals from about 400 rocks, most of which were submitted by 

geologists of the U.S. Geological Survey. A few samples were submitted by State and foreign geological surveys. Ages were determined of a variety of predominantly silicic to intermediate type 

igneous rocks representing most of the major bodies of intrusive rock 

in the United States. A limited number of determinations were also 

made on rocks from Mexico, Canada, Norway, Finland, France, 

Ceylon, Nyasaland, Formosa, Greenland, British Territories in 

Borneo, and Saudi Arabia.

A few determinations were made of detrital zircon from sedimentary 

rocks to obtain information of potential use in provenance studies. 

Although the geologist was advised against submitting metamorphic 

rocks because of the uncertainty in interpreting the results, some 

were received from those who believed that the age data might aid 

in the interpretation of the geologic history of an area.

65
66 STUDIES IN GEOCHRONOLOGY

The samples represented a geologic age span of Precambrian 

through late Tertiary. From periods after the Precambrian several 

rocks, whose geologic age has been established from good stratigraphic 

and paleontologic control, were either solicited from the field geologist 

or collected by the authors in the company of the field geologist in 

order to test the geologic consistency of the lead-alpha method. 

Many of the samples, however, represent intrusive bodies of questionable to totally unknown geologic age. Although the determined ages 

of many of these rocks cannot be properly evaluated from geologic 

evidence, their publication at this time may provide useful information 

to geologists engaged in field mapping of related rocks and to other 

investigators in the field of geochronology.

ACKNOWLEDGMENTS

The authors are indebted to many of their colleagues in the U.S. 

Geological Survey who collected large samples of a wide variety of 

igneous rocks for separation of accessory minerals used for the leadalpha age determinations. These include P, C. Bateman, A. J. 

Boucot, G. F. Brown, R. S. Cannon, Jr., R. W. Chapman, R. C. 

Ellis, Carl Fries, Jr., J. T. Hack, D. F. Hewett, H. L. James, M. R. 

Klepper, E. S. Larsen, Jr., B. F. Leonard, T. S. Lovering, J. B. Lyons, 

J. J. Matzko, T. McCullough, H. T. Morris, T. B. Nolan, W. C. 

Overstreet, J. P. Owens, W. T. Pecora, George Phair, A. W. Postel, 

A. W. Quinn, J. F. Robertson, C. P. Ross, R. G. Schmidt, D. R. Shaw, 

R. L. Smith, W. L. Smith, and R. A. Weeks.

Many other geologists also gave generously of their time in the 

collection of samples for lead-alpha age work. These include A. F. 

Buddington and H. D. Holland, Princeton University; 0. Kuovo, 

University of Helsinki; R. L. Dott, Oklahoma Geological Survey; 

C. E. Tilley, Cambridge University; G. M. Schwartz, Minnesota 

Geological Survey; F. W. Roe, Geological Survey Department of 

British Territories in Borneo; P. T. Flawn, Bureau of Economic 

Geology of Texas; L. T. Silver, California Institute of Technology; 

T. F. W. Barth, University of Oslo; R. M. Hutchinson, Colorado 

School of Mines; G. A. Russell, Department of Mines and Natural 

Resources of Manitoba; and R. E. Folinsbee, University of Alberta.

The authors are greatly indebted to W. F. Outerbridge, W. L. 

Smith, R. P. Marquiss, George Hayfield, John Mangum, Theodore 

Woodward, and Carl Mayhew for the exacting job of separating and 

purifying hundreds of accessory mineral samples from igneous rocks.

The authors are grateful to E. S. Larsen, Jr., Earl Ingerson, R. M. 

Garrels, and Michael Fleischer for their guidance and cooperation in 

setting up the facilities required for the lead-alpha age program.

This work was done partly on behalf of the Division of Research of 

the U.S. Atomic Energy Commission.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 67

NATURE OF THE DESCRIPTIVE AND 

EXPERIMENTAL DATA

This report presents a tabulation of the descriptive and experimental 

data on all the rocks whose age has been determined by the leadalpha method. For each rock the data, wherever available, include : 

Index number 

Petrographic classification 

Sample number 

Geographic locality 

Collector of the sample 

Mineral used for age determination 

Mesh size of the crystals used for age determination 

Alpha activity of the mineral used for age determination 

Total lead content of the mineral used for age determination 

Lead-alpha age of the mineral 

Geologic age * of the rock from which the mineral was separated, based on geologic

evidence of the authority cited.

The citation of the geologic age was taken from published papers or 

from written communications, whichever incorporated the results of 

the most recent and complete field data for a given rock or area. In 

this way, the reader can readily note the degree of consistency or inconsistency of the measured lead-alpha age with the geologic age 

assigned from stratigraphic, paleontologic, and field mapping investigations. Where geologists disagree on the geologic age of a rock, both 

field age assignments are given with the respective references.

A comparison between the lead-alpha ages and ages obtained by 

isotopic methods is given by Gottfried and others (1959),

METHOD OF CALCULATION OF THE AGE

The lead-alpha ages reported herein were calculated from the age 

equations and constants given and evaluated by Gottfried and others 

from the measurements of the alpha activity and total lead content 

of each accessory mineral.

The age equations, repeated here for convenience of the reader, are 

as follows:

Range 

(millions of years) Equation

0-200 u a per mg per hr

200 1,700 t.=t-}4kp

1,700 4,000 T=tfThe constants, c and k are functions of the thorium to uranium 

rji l.ios of the different accessory minerals xenotime, zircon, and monazi l.e. The thorium to uranium ratio given for each mineral is an

» The term "geologic age" is used In this report to refer to the divisions of geologic time founded on stratigrnplilu-iwleontologie evidence, as opposed to age expressed in number of years.
68 STUDIES IN GEOCHRONOLOGY

average value selected from published analyses (Gottfried and others, 

1959). These are as follows:

Selected 

Mineral thorium-uranium ratio e k (XIO7"4)

Xenotime__ __--_--_--___-__-__-__.___- 0.5 2,550 1.71

Zircon____-_____._--.______.__.__..___ 1.0 2,485 1.56

Monazite-_._____.___________ 25 2,085 .65

Where thorium and uranium have been experimentally determined for 

specific minerals included in the age tabulation, the c and k constants 

were obtained directly from the curves of Gottfried and others.

The ages measured on accessory minerals from rocks of well-established geologic age have been evaluated by Gottfried and others (1959); 

Lyons and others (1957); Quinn and others (1957); and Larsen and 

others (1958). This report is principally a complete compilation of 

experimental lead-alpha age data obtained by the U. S. Geological 

Survey between 1953 and 1957.

The spectrographic lead determinations were made by Claude L. 

Waring and Helen W. Worthing. The alpha activity was determined 

by Howard W. Jaffe and David Gottfried.

Where duplicate or replicate lead determinations were made on a 

given sample of zircon, all the values are entered in the tabulation 

and the mean value is used hi the age calculation. All the leadalpha age determinations are reported to two significant figures with 

the third and fourth figures hi italics.

REPRODUCIBILITY OP THE AGE DETERMINATION

Replicate age determinations were made of zircon from the same 

rock in 85 of the 411 rocks reported in the tabulation. Each age was 

reproducible to ±10 percent of the mean, or 10 million years, whichever is the greater, hi all but three of the rocks. In these three rocks 

each age was reproducible to only 10 to 34 percent of the mean. It 

is therefore reasonable to assume that, generally, any single age 

determination if repeated would be reproducible to ±10 percent of 

the mean or 10 million years. In a limited number of rocks, the age 

of more than one mineral has been measured. The agreement between the ages of zircon, monazite, and xenotime, separated from the 

same rock, is of the same order of reproducibility as obtained on different splits of zircon. The few determinations on thorite show a 

poorer agreement with cogenetic zircon.

ARRANGEMENT OF THE DATA IN THE TABULATION

The lead-alpha age determinations are listed in tabular form in a 

general order of increasing determined age. An attempt has been 

made to group data from petrographic and geographic provinces so 

that the entries do not always follow the strict numerical order of 

increasing age. An index number preceding each entry is provided 

for use hi a geographic index following the tabulation.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 69

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Lead-alpha age determinations of accessory minera

No.

6

7

8 

9

10 

11

Rock type 

Field No. 

Locality 

Collector

§

uartz latite__ _____________

L-3. 

Intrusive, near Sunnyside, 

Creede quadrangle, San 

Juan Mountains, Golo. 

D. Gottfried,G. Phair. 

Piedra rhyolite. _______ __ _

Z-8. 

Potosi volcanic series, San 

Critsobal quadrangle, San 

Juan Mountains, Colo. 

E. S. Larsen, Jr. 

Treasure Mountain rhyolite___

Z-43. 

San Juan Mounains, Colo. 

E. S. Larsen, Jr.

SC-1045. 

Dike intrusive into Silverton 

volcanic series, Alpine 

Gulch, San Cristobal quadrangle, San Juan Mountains, Colo. 

E. S. Larsen, Jr. 

Dacitic (?) , vitric ash _________

PJ-7.

Santa Fe group, sec. 17, 

T.19N., R.9E., Santa Fe 

County, N. Mex. 

R. S. Cannon, Jr., R. L. Smith.

DLP-55-10-4a.

Mineral

Zircon__

__.__do _ ______

-_.__do__-______

___ do__ ____

___ do _ ______

____.do__-______

Mesh size

-80+400 

-100+200

-100+200 

-100+200

-80+400 

-200+400

a per mg 

perhr

95 

730

111 

600

151 

180

Determ

0. 

1. 

1. 
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 71

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Lead-alpha age determinations of accessory minerals 

No.

fr

18 

19

20

21 

22

23]

Eock type 

Field No. 

Locality 

Collector

Lower tuff__________________

HM-2. 

Pre-intrusive volcanic rocks, 

Iron Springs district, Utah. 

J. H. Mackin. 

Syenite porphyry ____________

LS-2-55. 

West shoulder of Mineral 

Mountain, La Sal Mountains, Utah. 

D. R. Shawe. 

Monzonite porphyry _________

LS-7-55. 

Southern edge of intrusive, 

west-central part of North 

Mountain, La Sal Mountains, Utah. 

D. R. Shawe.

LS-6-55. 

Middle Mountain, La Sal 

Mountains, Utah. 

D. R. Shawe. 

Diorite porphyry, hydrothermallv altered. 

LS-8-55. 

South side of Miner's Basin, 

North Mountain, La Sal 

Mountains, Utah. 

D. R. Shnwe.

LS-10-54.

Mineral

Zircon __ _ 

_ _do _ __-_--

_ _ _do _____

 do 

Mesh size

-80+200 

-80+200

-80+200

-80+200 

-80+200

-80+200

a per mg 

per hr

262

2,270 

2,240

3, 180 

3,720

312 

297

401

Determi

2. 
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 73

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Lead-alpha age determinations of accessory miner

No.

30 

31 

32

33

34 

35

Bock type 

Field No. 

Locality 

Collector

Granodiorite. _______ ______

RJR-2-56.

Trenton Canyon, Nev. 

R. J. Roberts. 

Quartz monzonite _ ________

RJR-3-56. 

Copper Canyon, Nev. 

R. J. Roberts. 

Quartz monzonite (mineralized) . 

RJR-1-54. 

Copper Canyon, Nev. 

R. J. Roberts.

P-3-cc. 

S^ sec. 24, N^ sec. 25, 

T.26S., R.64E., head of 

Aztec wash, 4 miles southeast of Nelson, Clark 

County, Nev. 

E. H. Pampeyan.

P-2-cc. 

NEM sec. 4, T.23S., R.64E., 

about 1.5 miles northeast 

of center of Boulder City, 

Clark County, Nev. 

E. H. Pampeyan. 

Granodiorite_ _______ _

55-W-100. 

East side of Santa Rosa Peak, 

extreme southwest corner 

sec. 32, T.43N., R.39E., 

Humboldt County, Nev. 

R. Willden.

Mineral

__.-do __ -

___ _do___ _____

_-.__do _____

_-__.do__. ------

_____ do-_ 

Mesh size

-80+400 

-80+400 

-80+400

-80+400

-80+400 

-80+400

a per mg 

per hr

199 

387 

520

394

129 

365

Deter

3

7

5

2

5
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 75

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Lead-alpha age determinations of accessory minera

No.

42

43

44 

45

46 

47

Eock type 

Field No. 

Locality 

Collector

HTM-2. 

North Lily stock, 1,250 feet 

N.34°W. of North Lily mine 

shaft, East Tintic district, 

Utah. 

H. T. Morris.

HTM-1.

Silver City stock, from railroad cut near the Iron Duke 

mine, Tintic district, Utah. 

H. T. Morris.

P-50-49. 

Big Sandy Creek, Bearpaw 

Mountains, Mont. 

W. T. Pecora.

WTP-3. 

Rocky Boy stock, Pegmatite 

Peak, Bearpaw Mountains, 

Mont. 

W. T. Pecora. 

Dacite .._ _____ ______ _ __

S. 3673. 

Ban, 1st Division, West Sarawak, British Territories in 

Borneo. 

F. W. Roe. 

Granite. _ ___________________

South 3686.

Mineral

Zircon ___-_--

___-_do_ ~

___-.do_-_ -__

-_-_-do_--_.-_-_

____.do_ ..._.

_ .do 

Mesh size

-100+200 

-20U+400

-100+200 

-200 + 400

-80+100 

-100+200

+20 

-80+200 

-80+200

a per mg 

per hr

233

228

187 

223

290 

275

218 

227

225 

156

Determ

5. 

5. 

3. 

5. 

3
48

49

50

51

52

Tanjong Datu, 1st Division 

West Sarawak, British Territories in Borneo. 

F. W. Roe.

alkaline basalt. 

TPY-1. 

Northern Formosa. 

T. P. Yen.

483245. 

Hachita quadrangle, 

SEMNEM sec. 22, T.29S., 

R.16W., southwest New 

Mexico. 

C. Dane.

1895. 

Flat area, Flat Creek near 

Strandberg cabin, 1.5 miles 

northwest of Chicken Creek, 

Iditarod quadrangle, central 

Alaska. 

P. Killeen, M. White.

1810. 

Flat area, opposite placer cut 

on Chicken Creek, Iditarod 

quadrangle, central Alaska. 

P. Killeen, M. White.

3469.

Flint Creek of the Sulatna 

River, Ruby-Poorman district, Ruby quadrangle, 

central Alaska. 

M. White, J. Stevens.

.... _do__ _ _--

___ do ____ -_

% inch

crystals. 

-80+200

-200+400 

-60+100

-60+100

-80 + 200

21

250

275 

334

315

1,366

1,322

1,342
Lead-alpha age determinations of accessory minera

No.

53

54

55 

56 

57

Rock type 

Field No. 

Locality 

Collector

5044. 

Nixon Fork mining district, 

Crystal Shaft mine, Medfra 

quadrangle, central Alaska. 

J. J. Matzko, G. D. Eberlein. 

Kneehills tuff _ 

2415. 

Vitric-crystal tuff, stream bed 

of Threehills Creek, 6 miles 

north of Carbon, Alberta, 

Canada. 

R. A. Folinsbee.

CPR-120. 

Dike from dike zone along 

South Fork, Payette River, 

west of Lowman, Idaho. 

B. F. Leonard, C. P. Ross.

CPR-121. 

Camas Creek below Myers 

Cove, Casto quadrangle, 

Idaho. 

B. F. Leonard, C. P. Ross. 

Porphyritic biotite-muscovite 

granodiorite, somewhat 

gneissic. 

CPR-122. 

Near Idaho-Montana line, 

Lost Horse Creek, near 

Hamilton, Mont. 

B. F. Leonard, C. P. Ross.

Mineral

Zircon___ _______

_____do.___ __

_--__do_--______

_____do -----

____.do _ ______

Monazite.______

Mesh size

-60+100 

-100+400

-200+400 

-80+200 

-400

-80+200 

-200+400

-80+200 

-80+200

a per ing 

per hr

252 

268

624 

440 

624

403 

625

257 

3,385

Deter

5

5

4

6
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 79

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.rtW W

IIS 0>

UO

o

CO

o~

»o

O <N 

00

CO o

00

O5 CO 

0=

O

CO

o

COo"

CO

 0

o 

o"

<*'

10

CO

O 00

. I I

o"

CO

ccI 1

<N UO

CO <N

<N O»

00

00

O O

O O

<N <N

3

oo

00

oo o

0000 00 I I I

1 J si _ S C

a gg T:

O ^ O

,Q ^t o

S NS

fed ^'

» « c? ^ Opn .g O +

i e§ "3 § § "? ' bK*sf 2 ^ a S

Ec. t.

R

t,'

|

§43

tk. ^

-

oT

0)

c 

o

S

0) 

0 C)

C

 c

i " O

&'£>

2 °

H S a 

"S c

0 

T3

1?

"_l

:3 t*

5 S c? c

O Hi 0 t1S-g

<§ s

+a ef

"^ 0

 ** 05

, lls

 ^ «

- S o

S3

M r » L^ w>eo'g o 

_O<N S q> 'S

^^.2
Lead-alpha age determinations of accessory mineral

No.

65 

66

67 

68

Rock type 

Field No. 

Locality 

Collector

55-im-i.

Tobacco Root batholith, near 

Hollowtown Lake, southeast 

flank of Mount Jefferson, 5 

miles southwest of Pony, 

Mont. 

R. R. Reid. 

Zircon-rich "micro-placers" in 

dacite tuff. 

55K-307a. 

Of Tertiary volcanic rocks 

resting on eroded surface of 

Boulder batholith, Obelisk 

mine, Jefferson County, 

Mont. 

M. R. Klepper. 

Quartz monzonite _ _________

Z-2.

Satellitic stock of the Boulder 

batholith, Montana. 

R. A. Weeks.

Quartz monzonite__ _ _ ___

52-C-10a. 

Boulder batholith, from the 

border of the batholith, 7 

miles southeast of Helena, 

Mont. 

R. W. Chapman.

Mineral

_____do 

_____do_--_---_-

____.do__-_-___-

Mesh size

-80 + 400 

-200 + 400

-80+400 

-80+400

a per mg 

per hr

493 

192

336 

160

Determ

4. 

9
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 81

O

ft O

ft O

p -s.®

s

O 

CO

l>

<N

i-H

rH

cc

<N

*O

06

O 0 

OS OC

00

0

r-i

CO 

r-i

CO"

o"

CO O CO CO O O 

O O5 CO O O iCS

1 <N OS I> CO <N I>

> 0 O O O 0 O 

> O O O O O O

+ H > O C

) 00 «

1 1

c

73

r^O_*.

Is

*" dj cj ^ 

i"Spq PH'O

-f- -)- -j- -jo o o o

00 00 00 00

II 1 1

cS

"Xcp'S

g o os a O « rj O

o S S u M >; * 

S S c5

co^-

52-C-60. 

Boulder batholith, roadcut miles northeast ofElkPar 

Mont. 

W. Chapman. R. 

Alaskite

O r-l

I> I>

%£ SH - s 

2=1+3 03 'r< 

^l^

^Igj-S S 03 M C O 

*7{ «M " 55 -tJ Ja ° -S M 

£-P^ ^

^1^1^ ."" ^PngPH

opSj^a .a

lll^l

Sffl P4^

0

 d

icT

0

73

^T! fl

<1J O K." 03 «

;-|i n . i -^Oi,-! ^ r-e * « 

ofl S -g SW§ «

^ fl K~ § 0-^^! g

«lt 1 5 PS . I

^^l a j^ a

llgi! |1|ii . alM^lal^fl 

lil^HgilHp

!^!Z; PHr^iS^ PHf^

S g. tt

f-l -*= . -

<D O ^

5-W-l. 

Near margin of Bould the batholith, Boulder HSprings, Jefferson Count

Mont. 

R. Weeks. A. 
Lead-alpha age determinations of accessory miner

No.

75 

76

77

78 

79

Bock type 

Field No. 

Locality 

Collector

53C-160b. 

Granitic rock inclusion in 

quartz monzonite of the 

Boulder batholith, Montana. 

R. W. Chapman. 

Granodiorite ________________

G-155.

Snoqualmie batholith, along 

north slope of Goat Island 

Mountain, Mount Rainier 

National Park, Wash. 

D. Gottfried, W. L. Smith.

54-W-48. 

North side of Julian Creek, 

north center sec. 17, T.38N., 

R.42E., Osgood Mountains 

quadrangle, Osgood Mountains. Nev. 

P. E. Hotz.

G-203. 

Paymaster mine, Craters of 

the Moon Monument, Idaho, 

D. Gottfried, W. L. Smith.

BC-1-2. 

Sierra San Pedro de Martir 

Mountains, Baja California. 

L. T. Silver.

Mineral

___-_do_--_-____

-__-_do__. ___ _

_____do _ ___ _.

Mesh size

-80+400 

-80+200

-80 + 400

-80+400 

-100+200

a per mg 

per hr

340 

144

378

305 

3,529

Deter
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 83

o 

Q

<5 

O

o

O

o

o s HI O

P

PH

o

o

o 

»o

UO

el

0

CO

«5

o

<Noo"

rA

O i-H

TH

cT

1 1 l-H

ie5

CO

<N

^

»O

<N

CO

<N

(N~

(N

O

oioo"

-4

T(f

+

o o

o

O (N

o

O

o o

o

O (N

o

O

a

g

t

K

-2

1

3-

c3 

,0

^

-2

P

o 

u'R*

(n CO »l 

I?

fcf

o N.

t^ 03 ^ a

§ g

o a

T -s

O hD 

5^ C

Gu

2 

 1

ft\ T ' ' ~^t l/J A\ ^^ -2 S 0' R.S-S^S c^ rfi>S£ a>o ^

^"? S^ . g"? g 

OOfe^i

Z

co. C. Fri
Lead-alpha age determinations of accessory minera

No.

87

88 

89

90 

91 

92

Rock type 

Field No. 

Locality 

Collector

Granite _ ____ __ __ ____ __

CF-1. 

Isthmus of Tehuantepec area, 

near Huilotepec (Oaxaca) 

IVIexico. 

C. Fries, jr., B. Webber. 

Granite _______ __________ _

JAL-1. 

Four miles southeast of Jalapa 

(Oaxaca) Mexico. 

C. Fries, Jr., B. Webber. 

Tonalite__ ____ ______ ___ _

G-10. 

Southern California batholith, 

Aguanga, Calif. 

E. S. Larsen, Jr.

Green Valley tonalite_ _______

G-ll.

Southern California batholith, 

Green Valley, Calif. 

E. S. Larsen, Jr., D. Gottfried. 

Green Valley tonalite _ ____

SLR-138. 

Southern California batholith, 

Green Valley, Calif. 

E. S. Larsen, Jr. 

Tonalite. ______ __ ______ _

G-30. 

Southern California batholith, 

southwest of Palm Springs, 

Calif. 

E. S. Larsen, Jr., D. Gottfried.

Mineral

____.do-_______

_.___do __ _____

___-_do_--_- __

-_.__do_-_-_____

-_.__do _ _-_-_.

Mesh size

-80+200

-80+200 

-100+200

-100 + 200 

-100 + 200 

-100 + 200

a per mg 

per hr

310

104 

280

149 

340 

317

Determ

4. 
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 85

o 

O

o 

O

o

P

o 

Q

o 

O

C

ec

i£

cc

C

oc oc

C

l> C1-1 cr

cs

O

8

+o 

o

+200 00+200 +2 00+20U 00+2 00 + 200 00+200

00 

OJ

506320 5S
Lead-alpha age determinations of accessory minera

No.

101

102 

103

104 

105 

106

Rock type 

i ield No. 

Locality 

Collector

Mount Hole granodiorite- ____

Z-17. 

Southern California batholith, 

Mount Hole, Calif. 

E. S. Larsen, Jr.

Stonewall granodiorite _ _____

G-48. 

Southern California batholith, 

Stonewall Mountain, Calif. 

E. S. Larsen, Jr. 

Woodson Mountain granodiorite 

S-6. 

Southern California batholith, 

northeast of Descanso Junction, Calif. 

E. S. Larsen, Jr. 

Woodson Mountain granodiorite. 

Z-16. 

Southern California batholith, 

Descanso Junction, Calif. 

E. S. Larsen, Jr. 

Woodson Mountain granodiorite. 

G-32A. 

Southern California batholith, 

west of Elsinore, Calif. 

E. S. Larsen, Jr. 

Woodson Mountain granodiorite. 

S-2.

Mineral

Zircon. ________

_____do__-_---_-

_____do _ _-.-_-

Zircon. ________

Xenotime_____.

_____do ........

Mesh size

-100+200

-100+200

-100+200 

-100+200

-100+200 

-100+200 

-100+200

-100+200

apermg 

per hr

1,204

545

1,180 

6,430

1,235 

6,400

457

433

Deter
Southern California batholith, 

1 mile south of Temecula, 

Calif.

E. S. Larson, Jr.

107 Granite_____________. 

Z-15.

Southern California batholith, 

Rubidoux Mountain, Calif. 

E. S. Larsen, Jr.

108 Granite___________. 

EL-167.

Southern Cah'fornia batholith, 

Rubidoux Mountain, Calif. 

E. S. Larsen, Jr.

109 Rattlesnake granite___.____.. 

X-101.

Southern California batholith, 

Cuyumaca quadrangle, California. 

E. S. Larsen, Jr.

110 Granodiorite_ _______________

RCE-54-7-28A.

Pomona Tile quarry, Mojave

Desert area, California. 

R. C. Ellis.

111 Granite_______________.

RCE-54-7-14B.

Neeiiach quadrangle, Mojave

Desert area, California. 

R. C. Ellis.

112 Quartz monzonite______-__.

G-21.

Southern California batholith, 

Providence Mountain, Calif. 

E. S. Larsen, Jr.

113 Quartz monzonite_._______.

G-24M.

Southern California batholith,

Soda Lake, Calif. 

E. S. Larsen, Jr.

Zircon (metamict).

Zircon.

Xenotime.

Zircon.

.do.

.do.

Zircon (metamict).

-100+200

-100+200

-100+200

-80 + 200

-80+200

-100 + 200

-100+200

2,700

725

1,743

237

866

610

4,660

& 
Lead-alpha age determinations of accessory mineral

No.

114 

115 

116

117

118 

119

Rock type 

Field No. 

Locality 

Collector

Quartz monzonite _ _________

RCE-54-7-14C. 

Rosamond quadrangle, Mojave Desert area, California. 

R. C. Ellis.

RCE-54-7-18A. 

Ivanpah quadrangle, Mojave 

Desert area, California. 

R. C. Ellis.

RCE-54-7-27C. 

White tanks, south of Twenty 

Nine Palms, Mojave Desert 

area, California. 

R. C. Ellis. 

Granite _ ____ ______ _

RCE-54-7-28B. 

Granite Mountains, southeast 

of Apple Valley, Mojave 

Desert area, California. 

R. C. Ellis. 

8uartz monzonite___ _________

-28. 

Southern California batholith, 

Berdoo Canyon, Calif. 

E. S. Larsen, Jr.

G-15.

Southern California batholith, 

Cottonwood Springs, Calif. 

E. S. Larsen, Jr.

Mineral

Zircon. ____ ___

__--_do_-____-_-

__--_do___---_-

_-_-_do_--~.-_-

-_.__do.---_--__

___._do_--~-__

Mesh size

-80+200 

-80+200 

-80+200

-80+200

-100+200 

-100+200

a per mg 

perhr

203 

171 

267

590

385 

190

Determi

8. 

& 
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 89

PS

 *

"Si O5

! §

0«

o

p

o 

Q Q

CO CO 

05 CO

W5 

(N

CO'

lO 1C

CO

0 

CO

If,

<M

^ CO

T-l CO

(N

CO CO CO

i-l CO (N 

(N

CO 

CO (N

»o

CO

CO 1 I 

(N

CO 

05 

CO

CO

CO

0

o

<M

+

§

1

0 0

^2 ^D

<M (N

-[_ -[_

§ §

i I i I 

1 1

0

^D

(N

-|_

O

0

rH 

1

O

0

(N

-j0 

O

1 1 1

o

0

(N

-[-

O

o» 1 1

0

o

<M

+

§

i i 

1

c X

1 flj 

JH S: ^ 52 pqA o 

qtH a!

Cl&'rl

« J

oT >»!« .a-s'a

^§0

c ° - .

3O iS oj

05

. s p

0 |

H S

4TH5 _CI-H c3 

g^h^

1^5 T3 _t? gs^a' o3_x 2

^^oel 

l^iai

a

"N 

a

|

S

PS 0

-to

05 c3

*j Oh^ T3 Q a. 

cr^Sj o 3 ^ r

e

§

5

||

r

O CO

rfcb^

 i^

g-ri

 * QJ

ll^&s'i

fsl

Jjpn'^

IT! -<i ,-H & g

! slo-S-n *i*

o . c-go.2 s l?s«"§. PS T) S^i_; fl°P 

g JaQ^gpq 

Ow'^ tfoS

y ill.

sNallk l^ss^g^

S PWOPL(.

^^.sp^ a a ^pq ^ o o
Lead-alpha age determinations of accessory minera

No.

126

127

128

129 

130

Rock type 

Field No. 

Locality 

Collector

Granodiorite . ____________ _

PB-7. 

Big Pine quadrangle, southeast corner sec. 33, T.9S., 

R.33E., one-fourth mile 

south of Third Lake, near 

Bishop, Calif. 

P. C. Bateman. 

Granodiorite-- ________ _ ___

PB-5. 

Big Pine quadrangle, NWJ^ 

sec. 14, T.10S., R.33E., near 

Bishop, Calif. 

P. C. Bateman. 

Quartz monzonite _ _________

PB-2. 

Mount Tom quadrangle, west 

of surface workings Pine 

Creek mine, near Bishop, 

Calif. 

P. C. Bateman. 

Quartz monzonite _ ____ __

54-EM-l. 

Hunter Mountain batholith, 

southwest corner Ubehebe 

quadrangle, Inyo County, 

Calif. 

E. M. MacKevett. 

Isabella granodiorite _________

EMM-1. 

Kern River uranium area, 

California. 

E. M. MacKevett.

Mineral

Zircon _ _ _ ___

 __do____ 

_ __ do __ __ _

 __do_-_-_-__

_____do - __ _

Mesh size

-100+200

-100+200 

-100+200

-80 + 200

-80+200 

-200+400 

-400

a per mg 

perhr

221

331 

796

145

283 

320 

351

Dete
131

132

133

134

Half Dome quartz monzonite.

53-PB-10.

Mount Lyell quadrangle, 

N WJ£ sec. 28, T.1S., R.23E., 

1 mile southwest of Tenaya 

Lake, Yosemite National 

Park, Calif.

P. C. Bateman.

El Capitan granite.__________

53-PB-9.

Yosemite quadrangle at junction of Tamarack and Cascade Creeks, sec, 25, T.2S., 

R.20E., Yosemite National 

Park, Calif.

P. C. Bateman.

Granodiorite. ___-._-___-_-.__-

53-PB-8.

Yosemite quadrangle, at junction of Avalanche Creek with 

Merced River, NWJ^ sec. 

14, T.3S., R.20E., Yosemite 

National Park, Calif.

P. C. Bateman.

Quartz diorite-______________

MD-180-3.

West-central part of French 

Gulch quadrangle, 1.3 miles 

east from Buckhorn Summit, U.S. Highway 299, 

Shasta Bally bathoHth, 

Klamath Mountains, Shasta 

County, Calif.

J. F. Robertson.

Thorite. 

Zircon _.

.do.

.do.

-do.

 100+200 

100+200

-100+200

-100+200

-100+200

10, 370

330

395

385

276
Lead-alpha age determinations of accessory minera

No.

135

136 

137

138 

139

Rock type 

Field No. 

Locality 

Collector

Bio tite-horn blende quartz diorite. 

MD-180-4. 

Southeast part of French 

Gulch quadrangle, where 

Silver Falls mine road crosses 

Andrews Creek, Shasta Bally 

batholith, Klamath Mountains, Shasta County, Calif. 

J. F. Robertson.

Ta-1. 

Facies of the Bald Mountain 

batholith, Sumpter quadrangle, Baker County, Oreg. 

W. Taubeneck.

FGW-12-53. 

Grouse Creek, Medford 

quadrangle, Jackson County, 

Oreg. 

F. G. Wells. 

Granodiorite _______ __ _

FGW-3-54. 

Medford quadrangle, Jackson 

Countv, Oreg. 

F. G. Wells. 

Biotite - hornblende - pyroxene 

diorite. 

CPR-119. 

Diana school, Quartzburg district, Idaho. 

B. F. Leonard, C. P. Ross.

Mineral

Zircon _ _______

_____do___--___-

-_.-_do___--___-

Zircon (and included apatite).

-___do__ _

Mesh size

-100+200

-80+200 

-80 + 400 

-80+400

-80 + 200 

-200+400

a per mg 

per hr

197 

223

153 

230

322

291

100 

116

Determ

5

3. 0, 4

4
140

141

142

143

144

145

Quartz diorite______ __ _____

L-113.

Idaho batholith, Salmon River 

below Stanley, Idaho. 

E. S. Larsen, Jr. 

Quartz diorite_____ _____ _

L-217. 

Idaho batholith, near Bungalow, Idaho. 

E. S. Larsen, Jr.

L-81. 

Idaho batholith, South Fork 

Payette River, Idaho. 

E. S. Larsen, Jr.

L-70. 

Idaho batholith, near Cascade, 

Idaho. 

E. S. Larsen, Jr. 

Porphyritic biotite granodiorite. 

L-53-573a. 

Idaho batholith, 2,000 feet

north-northwest of Peak 

8520 near Pilot Peak trail, 

Big Creek quadrangle, 

Idaho. 

B. F. Leonard. 

Porphyritic biotite-muscovite

granodiorite. 

L-53-88. 

Near Big Creek Ranger Station, Idaho batholith, Big 

Creek quadrangle, Idaho. 

B. F. Leonard.

___ do _________

Thorite _____

___ do _____

-100+200

-100+200

-100+200

-100+200

-100+200

-80+200

-80+200

804-90O

825

1,375

225

370

210

340

2,726

2 fi7R

1
Lead-alpha age determinations of accessory minerals 

No.

146

147 

148

149 

150 

151

Rock type 

Field No. 

Locality 

Collector

Hornblende-biotite diorite _____

L-53-377 

Half a mile southwest of 

Mahan cabin, northwest 

rectangle Big Creek quadrangle, Idaho. 

B. F. Leonard. 

Biotite-hornblende diorite ___

CPR-118. 

Border facies of Idaho batholith, Horseshoe Bend, Idaho. 

C. P. Ross, B. F. Leonard. 

Biotite-augite-hypersthene diorite. 

CPR-117. 

Border facies, Idaho batholith, Hailey, Idaho. 

C. P. Ross, B. F. Leonard.

G-200. 

Idaho batholith, near Stanley, 

Idaho. 

D. Gottfried.

L-110. 

Idaho batholith, below Stanley, Idaho. 

E. S. Larsen, Jr. 

Granodiorite.___ ___ 

L-288. 

Idaho batholith, near Atlanta, 

Idaho. 

E. S. Larsen, Jr.

Mineral

Zircon__ _______

. _ do _ _

Mesh size

-80 + 200

-80+200 

-80 + 200

-100+200

-100+200

-100+200

apermg 

per hr

158

120 

173

190 

1,000 

700

Determin

28, 3

5. 0

8.0
152

153

154

155

156

157

158

159

Quartz monzonite _ ___.__.__

L-207. 

Idaho batholith. Indian Grave 

near Powell, Idaho. 

E. S. Larsen, Jr. 

Granite _ _ . .__

G-199.

northeast of Garden Valley,

Idaho. 

D. Gottfried.

M-60. 

Idaho batholith, near Placerville, Idaho. 

E. S. Larsen, Jr.

L-264. 

Idaho batholith area near 

Idaho City, Idaho. 

E. S. Larsen, Jr.

L-269. 

Idaho batholith area, near 

Idaho City, Idaho. 

E. S. Larsen, Jr. 

Muscovite placer. __._._. 

L-267. 

Idaho batholith area near 

Idaho City, Idaho. 

E. S, Larsen, Jr.

0-7. 

Idaho batholith, near Idaho 

City, Idaho. 

E. S. Larsen, Jr. 

Gran odiorite ___.-_-_-. __

HCD-63. 

Gem stocks, Coeur d'Alene 

district, Idaho. 

A. B. Griggs.

___ do.........

_.__.do-_ 

Xenotime......

Monazite _ __._

___..do_. ..._

. ....do... ......

 _do_. ....

.....do..... __

Zircon. ... __

-100+200

-100+200

-100+200

-100+200

-100+200

-100+200

-100+200

-100+200

-100+200

-100+200

922

1,970

5,617

6,025

2,983

2,994

2,888

2,634

3,241

292
Lead-alpha age determinations of accessory miner

No.

160

161

162

Rock type 

Field No. 

Locality 

Collector

Granodiorite. _______________

HCD-62.

Gem stocks, Coeur d'Alene

district, Idaho.

A. B. Griggs.

Rare-metal deposits of monazite, niobium-bearing ilmenite segregated in limestone layers in Precambrian

metasedimentary terrane

near border zone of Idaho

batholith.

ID-9-30.

Indian Creek area, Mineral

Hill district, Lemhi County,

Idaho.

E. P. Kaiser.

Rare-metal deposits of monazite, niobium-bearing ilmenite segregated in limestone layers in Precambrian

metasedimentary terrane

near border zone of Idaho

batholith.

ID-9-35.

Indian Creek area, Mineral

Hill district, Ijemhi County,

Idaho.

E. P. Kaiser.

Mineral

Zircon and

thorite.

Monazite»._ .

do

Mesh size

-100+200

+ 60

+ 60

a per ing 

per hr

1,739

578

1,024

Dete
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 97

*

ho S fr o a A-S o ot5

s~ s a>_^»ci >H 

I'S rf

o 

P

o

ft c5p

o

p A.

"5

c> CJ

(Nr-(

cT

CO

eo

(0 

t~

oo

s

I

O

o

<N

o

00

-a

1 OQ

 era

!.'

 03 S* S «

-

S^S^MS^SI^UI^

KM WP* Opq QOOo

6. 

Halford, Sultan quadWashington. gle,

Smith. oried, W. L

g «

g'Bb . * S ^

|l i

13 £ w 0* .4

t|l .£ a « «

2r% O-f 1°|3 ^il^ 

Illl lS«N g'43 2"o :§?» 'HOO P
Lead-alpha age determinations of accessory mineral

No.

IRQ .toy

170

171

172

173

Rock type 

Field No. 

Locality 

Collector

Tonalite... _ ________

HC-2.

Chelan batholith, Lower

Knapp Coulee (east side),

Chelan quadrangle, Washington.

C. A. Hopson.

Gneissic hornblende-quartz

diorite.

FW-60-55.

Chelan batholith, Holden

quadrangle, north side

Entiat River, 3 miles south

of Holden, Wash.

F. W. Cater.

Granodiorite____ .

DFC-1 06-55.

Holden quadrangle, Washington.

D. F. Crowder.

Tonalite. ________ _

HC-1.

Chelan batholith, Upper 

Knapp Coulee (west side),

Chelan quadrangle, Washington.

C. A. Hopson.

Tonalite._____ _ _ _ _

DFC-107-55.

Holden quadrangle, Washington.

D. F. Crowder.

Mineral

Zircon _ . ___

. .do.........

. _ .do _____

_. ...do... ......

. _ .do...... _

Mesh size

-80+200

-80+200

-80+200

-80+200

-80+200

apermg 

per hr

no yo

78

110

83

56

Determ

4

3

5

4

^C

2
174

175

176

177

178

179

Quartz diorite_____________

FC-1.

Holden quadrangle, Washington.

F. W. Cater.

Granodiorite_ _______________

G-122.

Similkameen batholith, 2 miles 

from Bichter Ranch, near 

Washington-British Columbia border, British Columbia, Canada.

D. Gottfried, W. L. Smith.

Granodiorite_ _______________

REF-1.

Nelson batholith, Lower Arrow 

Lake district, British Columbia, Canada.

R. A. FoLinsbee.

Leucosyenite. _______________

3881.

Near Mount Fairplay, milepost 29, Fortymile district, 

east-central Alaska.

A. Nelson, J. J. Matzko.

Granodiorite_______________

54-APr-106.

Taku Inlet, near outlet of

Turner Lake, west of Juneau,

southeastern Alaska. 

G. Plafker. 

Diorite__.__________________

55-ASn-242.

Tolstoi Point, Prince of Wales 

Island, northeast-central 

part of Craig quadrangle, 

southeastern Alaska.

C. S. Sainsbury.

.do.

.do.

.do.

.do.

Zircon

(metamict).

Zircon.

.do.

-100+200

-80+200

-100+200

-60+200

-200+400

-100

74

160

310

1,270

1, 134

1,476

1,550

1,620

1,930

1,594

2,600

152

142
Lead-alpha age determinations of accessory minera

No.

180

181 

182

183 

184

185 

186

Bock type 

Field No. 

Locality 

Collector

13-A. 

Porcupine Creek, Kuskulana 

River area, Chitina Valley, 

east-central Alaska. 

J. F. Seitz. 

Granite porphyry...-.-------

SCC-1. 

Near San Manuel, Ariz. 

S. C. Creasey. 

Pegmatitic facies of nepheline 

syenite. 

56-2. 

Larvikofjorden, Norway. 

T. F. W. Earth. 

Pegmatitic nepheline syenite.. 

56-3. 

Tveitdalen, Norway. 

T. F. W. Earth.

TB-7. 

Barkevik, Langesundsfjord, 

southern Norway. 

T. F. W. Earth.

56-8. 

Laven Langesundsfjord, southern Norway. 

T. F. W. Earth. 

Cataclastic metanorite _ . 

N-l. 

Djupdalen, Losby, Lorenskog 

Herad, Akershus, southern 

Norway. 

H. Faul, 0. Holtedahl.

Mineral

Zircon.... ...

___ do _____

.....do... ___ . 

.....do... ___

.....do... ___ .

.....do... ___

Mesh size

-80+400

-80+400 

+ 20

+20 

+20

+ 20 

-100+200

apermg 

per hr

283

73

177

76 

75

324 

108

Determ

3. 0, 3

4

5. 0, 5

7. 0, 8
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 101

9'£

'S O* fit a) j3 

PH W> 0

>>8 fl 1«

W

^» ®

I*8' & 

P

Carboniferous (?) 

(pre-Santa 

forma- Rosa

C. tion). 

Jr. Fries, 

si ** I1

0|gj

H

Pre-Permian. 

Bramkampn< 

1956. others, 

$

us

CO 00

o

00

CO

CJ

US

O

CO

CO

o»

CO 00eo"

c

 G

-d"

o PI a

ik, Langesundsf; 

s^ay. 

rEarth, .

venite- ines.--.

c c

-s

S

O

**? 1

8

If 

« rfi

' -cT . ^< ^^

0

 d

o ® 's^1

Bedil, Divi 2nd;, Sarawak, British 

Borneo. in3

Eloe.

c

-c

 +» CQ

>S 8-SE

S o

Division, 2nd u,ivak, British Terrii

>rneo. 

Roe.

C

T:

S3

'a* &

3s X>

1 ^ ,

O psj _-2

ol tl e 

M o* 1^ 5

i"S

§1 .ga

^ bD

*«> 05 

_J ^ 42 ls-i 1 4 §11 ; l "C * * o3 1 Is! i 51 ~ 'S -ja «SA t J-:§|^^w. §^1^^121^.

' 5 Wtf^^O

506S20 59 6
Lead-alpha age determinations of accessory miner

No.

194

195 

196

197 

198

199 

200

Rock type 

Field No. 

Locality 

Collector

Coarse gray porphyritic granite. 

SA-2. 

Eastern side of eastern batholith, Saudia Arabia. 

G. F. Brown. 

Granite rock________________

SA-3. 

Jebal Z'aba, Saudi Arabia. 

G. F. Brown. 

Fine-grained gray granodiorite. 

SA-4. 

Taif , Saudi Arabia. 

G. F. Brown.

Sa-6. 

Dhalm, Saudi Arabia. 

G. F. Brown.

S-46. 

Ashaway quadrangle, Rhode 

Island. 

W. L. Smith. 

Narragansett Pier granite _____

Q-55-3.

Ashaway quadrangle, Rhode 

Island. 

A. W. Quinn. 

Westerly granite____ 

Q-55-4. 

Ashaway quadrangle, Rhode 

Island. 

A. W. Quinn.

Mineral

Zircon_._______

* - ClO 

do - 

Monazite _ ____

Mesh size

-60+200

-60+200 

-60+400

-60+400 

-80+200

-80+200 

-80+200

otpermg 

per hr

460 

360 

483

2,083 

1,970

380

410 

462

304 

300 

5,494

Deter

3

48
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 103

o

ft o

ft o

fl o-

. go 

§-<

£

fl

O 

fi

% fr- 

(N

s

o

oo

oo

ooIN**

o oo ooo oooo

o 

oo

o

o

<N

o oo

o

oo

a 

o o

&

<%

 ~ s sa-S

ISH {23 

*rt <p

a £

g|

&I<H

&

11 50

O "

oT o

i12 * 

 oo.

J

O S «Q af 1 -1

S o3 a> i°l

w «w S

0 oW o1

.1

o .^j

(P Tj< £H

^z»0

^ f||l^ P i^i^isl^ P iil^llilll^

O"

3
Lead-alpha age determinations of accessory minera

No.

208 

209

210 

211

212 

213

Rock type 

Field No. 

Locality 

Collector

Q-53-39. 

Tower Hill Road, 2,500 feet 

south of Mooresfield road, 

Narragansett Pier quadrangle, Rhode Island. 

A. W. Quinn. 

Scituate granite gneiss ___ ___

Q-53-37. 

Georgiaville quadrangle, Fornum Pike, 1,200 feet southeast of west end of Capron 

road, Rhode Island. 

A. W. Quinn. 

Oneco granite. ... _______

53-S-48. 

Moosup, Conn. 

W. L. Smith. 

Syenite.- _______ ___ ______

Vt-Sy-56J-12. 

White Mountain plutonic-volcanic series, near summit of 

Mount Ascutney, Vt. 

H. W. Jaffe, J. B. Lyons. 

Granite _ _ _ ______ ______

Vt-Gr-56J-13. 

White Mountain plutonic-volcanic series, below summit 

of Mount Ascutney, Vt. 

H. W. Jaffe, J. B. Lyons.

NH-M-56J-17.

Mineral

__-_.do_________

_____ do... ....._

__.__do___ ......

.....do. __ ....

..._.do_. _ ....

Mesh size

-80+200

-80+200

-80+200

-80+200 

-200+400

-80+200 

-200+400

-80+200

apermg 

per hr

800

352 

251

544

166 

214

247 

373

240 

260

Determ
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 105

o 

ft

o

fl o

ft

CO O*Q C5 0*0 * co

CNINNIN

>oco 

coco

IO

coco

oocot>- us

«o

IOCD1O< oooooi

OINCO 

CO CO CO

00

O3

(N

co oo "*O

o«oot>-

o

o

o 

oo

o 

o

oo 

oo o

o

CO
Lead-alpha age determinations of accessory mineral

No.

218 

219

220 

221

222

Rock type 

Field No. 

Locality 

Collector

Mount Osceola granite _______

33-BNH-17.

White Mountain plutonic-volcanic series, Mount Chocura 

quadrangle, New Hampshire. 

A. Butler. 

Fayalite quartz syenite, ______

BNH-20. 

Devils Slide ring dike, White 

Mountain plutonic-volcanic 

series, Percy quadrangle, 

New Hampshire. 

A. Butler.

MR-1. 

Stock, Monteregian Hills, 

Mount Royal, Montreal, 

Quebec, Canada. 

J. B. Lyons. 

Winnepesaukee quartz diorite__ 

NH-WQd-56J-16. 

New Hampshire plutonic series, 

south of Belknap Point, 

Lake Winnepesaukee quadrangle, New Hampshire. 

H. W. Jaffe, J. B. Lyons. 

Kinsman quartz monzonite___ 

NH-LM-1-52.

Mineral

Zircon. ________

Zircon 

Th:U=2.1 

c= 2,385. 

Chevkinite 

Th:U=54 

c= 2,050 

fc=0.50X!0-* 

Zircon 

(metamict) .

Zircon_________

Zircon 

Th:U=0.4

Mesh size

-60+200

-60 + 200 

-100+200

-80 + 200

-80+200 

-200+400

-100+200

apermg 

per hr

470 

723 

843

465

443

995 

2,323

353 

391

248

Determi

210

4
223

224

225

226

New Hamphire plutonicseries, 

Lovewell Mountain quadrangle, New Hampshire. 

J. B. Lyons.

Kinsman quarts monzonite _

NH-C 2-52. 

New H ampshire plutonic series, 

Cardigan quadrangle, New 

Hampshire. 

J. B. Lyons. 

Bethlehem gneiss ____________

NH-K-8-52-1.

New Hampshire plutonic series, 

Rumney quadrangle, New 

Hampshire. 

J. B. Lyons.

NH-S-4-52-1. 

New Hampshire plutonic series, 

Sunapee quadrangle, New 

Hampshire.

J. B. Lyons.

Concord granite. ___________

NH-Big-56-J-20. 

Binary granite, New Hampshire plutonic series, Swenson 

quarry, Concord, N.H. 

H. W. Jaflfe, J. B. Lyons.

c= 2,560 

k =1.74X10-*

Monazite 

Th:U=33 

c= 2,065 

fc=0.61X10-*

__.__do____- __

Zircon

Th:U=1.4 

c= 2,455 

fc =1.47X10-* 

Monazite

Th:U=8.5 

c=2,180 

fc=0.87X10~* 

Xenotime

Th:U=54 

c= 2,048 

fc=0.56X10~*. 

Monazite _ ____

 100+200 

-100+200

-100+200

-100 + 200

-100 + 200

-100+200

-80+200

4,351 

333

246

949

2,922

4,053

5,352
Lead-alpha age determinations of accessory minera

No.

227

228 

229

230 

231

Bock type 

Field No. 

Locality 

Collector

Concord granite. ___. 

NH-C-4-52-1. 

Binary granite, New Hampshire plutonic series, Cardigan quadrangle, New Hampshire. 

J. B. Lyons. 

Pegmatite in Concord granite 

NH-C-5-52-E. 

New Hampshire plutonic series, 

Cardigan quadrangle, New 

Hampshire. 

J. B. Lyons.

NH-Gr-56-J-19. 

In Fitchburg pluton on U.S. 

Highway 3, 4.2 miles south 

of Suncook River, Martin, 

Suncook quadrangle, New 

Hampshire. 

H. W. Jaffe, J. B. Lyons.

NH-di-56-J-18. 

Exeter pluton, between Exeter 

and Eppingj N.H. 

H. W. Jaffe, J. B. Lyons. 

Metarhyolite_ __ __ 

NH-L-1-56.

Littleton formation, Littleton, 

N.H. 

J. B. Lyons.

Mineral

Monazite 

Th:U=46 

c= 2,052 

fc=0.58X10-*.

Zircon ________

___ do ______

_____do______ 

Mesh size

-100+200

-100+200 

-80+200

-80+200 

-80+200

a per ing 

perhr

2,784

5,285 

394

75 

53

Dete
232

233

234

235

236

237

238

Felsic volcanics,_____________

NH-Mo-3-56.

High grade zone of Littleton 

formation, east of Lisbon, 

N.H.

J. B. Lyons.

Granite_______._______....

NH-MW-4-52-1.

Oliverian plutonic series, 

Mount Washington quadrangle, New Hampshire.

J. B. Lyons.

Lebanon granite, border gneiss.

NH-H-6-52-1.

Oliverian plutonic series, 

Mount Washington quadrangle, New Hampshire.

J. B. Lyons.

Lebanon granite_'_____ 

NH-H-1-52.

Hanover quadrangle, New 

Hampshire.

J. B. Lyons.

Aplite in Lebanon granite.....

NH-H-2-52-1.

Oliverian plutonic series, 

Hanover quadrangle, New 

Hampshire.

J. B. Lyons.

Granite of Mascoma group ..

NH-H-50-52.

Oliverian plutonic series, 

Mascoma quadrangle, New 

Hampshire.

J. B. Lyons.

Pink granite .

Me-Gr-56J-21.

Biddeford granite, Kennebunk quadrangle, Wells, 

Maine.

J. B. Lyons, H. W. Jaffe.

.do.

Zircon

Th:U=2.3

c=2,390

fc 1.31X10-*

Zircon 

Th:U=l.l 

c=2,475 

fc=l. 55X10-*

Zircon 

Th:U=0.56 

c=2,540 

fc=1.69X10-*

Zircon 

Th:U=0 

c=2,632 

fc=1.90X10-*

Zircon

Th:U=1.3

c=2,460

k=1.50X10-*

Zircon.

 80+400

 100+200

-100+200

-100+200

 100+200

 100+200

-80+200

-200+400

165

498

217

574

980

514

348

410
Lead-alpha age determinations of accessory minera

No.

239 

240 

241 

242

243 

244

Rock type 

Field No, 

Locality 

Collector

Granite _ ____ __ __________

AB-1. 

Near Parlin Pond, Jackman, 

Maine. 

A. J. Boucot.

JBL-Me. 

Near Parlin Pond, 5 miles 

south of Jackman, Maine. 

J. B. Lyons.

AB-2. 

Katahdin batholith, near Ripogenus dam, Maine. 

A. J. Boucot. 

Kineo rhyolite, intrusive phase. 

AB-3. 

Northeast part of Brassua 

quadrangle, Somerset County, Maine. 

A. J. Boucot.

AB-5. 

Big Dump quarry, St. George, 

New Brunswick, Canada. 

A. J. Boucot. 

Gray granite__________-_-___

AB-6. 

Southeast tip of Pocologan 

Harbor, Charlotte County, 

New Brunswick, Canada. 

A. J. Boucot.

Mineral

Zircon__ _______

_____do_- ...

_ __ do -----

___-do-___ __

_____do____. _

___ do _____

Mesh size

-80+200 

-80+200

-80+200 

-200+400

-200+400

-80+400

-80+200 

-200+400 

-400

apermg 

perhr

315

248 

237

212 

230

95

363

164 

229 

232

Determ
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 111

.

fS-gS orfS-1

Sil

M

I

O 

P

O

p

O

p

*§ .

'E S

> §§

 §8,3

0|>£

Sfls

Hi

O

p

O

p

co

»0 

<N

O

CO

o 

o

o 

o

o 

o

+ +

o 

o

<N

fl'

£' 8(

Cs!

.2 ®

it

T1 *3

»H o'Q 

*S "S

9 3 O rr< §1-fi g

-3'S

. ftoS

aS* w ?

|?J I? 3 " 

fj,

;j|figPg|!|fj{f|l.

0"-5^sSa3 * tS y O ^* » » O ^ O H«4 ^ i 2 -» ^* y-i |l2! ^SK I3^ 33 gA3Sflrigiia!Sri^ftaia« OiziW H^^iziW H^fcW H^G?

CO
Lead-alpha age determinations of accessory minera

No.

252 

253

254 

255

256

257

Rock type 

Field No. 

Locality 

Collector

Swarthmore granodiorite 

AWP-1.

Near Springfield, Philadelphia 

area, Pennsylvania. 

A. W. Postel.

AWP-8. 

Near Falls Bridge, Fairmount 

Park, Philadelphia area, 

Pennsylvania. 

A. W. Postel. 

Swarthmore granodiorite. 

S-23. 

Near Springfield, Philadelphia 

area, Pennsylvania. 

A. W. Postel. 

Aplitic phase, Swarthmore 

granodiorite. 

S-16. 

Near Springfield, Philadelphia 

area, Pennsylvania. 

A. W. Postel. 

Swarthmore granodiorite __

AWP-5. 

Intermediate replacement 

type, East Lake Park, Philadelphia area, Pennsylvania. 

A. W. Postel. 

Swarthmore granodiorite .

AWP-6. 

Intermediate replacement 

type, Clifton Heights, Philadelphia area, Pennsylvania. 

A, W. Postel.

Mineral

Zircon. ___..____

. .do 

.....do __ . __

___ do _____

.....do _____

__ .do ____ ._

Mesh size

-80+400 

-80+400

-80+400 

-80+400

-80+400 

-80+400

apermg 

perhr

297 

288

240 

247

220 

250

Determ
to

8

to 

a> 

to

b^ 

^ *di? * 

Ll^

I?

S'^8,

^ ^jg S 

CD «T CD ^4 «j § < 8 j * 

to

CO

O>gJ»

bO

Cft

o

to 

Cn

CO

to 

en

00

%>& &>&> ff>2> 

^*t<-" *? <-"' ^* ? __ -*»* ?* R 

o g 

go

$$?

W -' 

*" &g 

S 1* 

^ £° 

« KM- 

"0^3

sMl^sjuSg^plSI^Si

<j £ «P<fovi hj<! >S-o -derM£". | 5-0 H^&Slsfcl'^l^*!*?:^

<3 fiT^ > 00 « "-"OOrtrJ^ K K S CD 00 £; 

i-i3 i-'Ict-^wj'" C*ct->-)t;M fff^HpSS 

5? 3i-j 5 o> a B P 5 ^n> S2.P S ^.(f.S 

§IT

I*

e2. o 

 §KE? 5-fiT?-

»g51"

pr

g

tsto

O 

O

I

00

O

sO

0

O

8

O

CO

-J

O

to

CO

to

O

p

"o oo a> H* to 

0 0000 

1 i <i 

O Cn 

CO

o

Cn Cn -a co 00 

IO tO 00 1 I- CO 

<K> <K> 0, *» 0 

I?

o o w o si 

o o o o S.B 

g* <ra 2. o 

to' i 

to

CO

to

to

to

*Q

O 

O

to

_to

to

Cn

to

CO

Cn

*>

00

^

I-HMC? l_i 

13 *" ct- <! 

f * < CD 

Pn" P S 

e-8

Cfip'

aov ,10 saoaNDi snvaamw 8H 
Lead-alpha age determinations of accessory miner

No.

265 

266 

267

268 

269

270

Rock type 

Field No. 

Locality 

Collector

Granite f elsophyre __ __ _ _ _

CM-2. 

Dike, Crab Bottom road, 2J^ 

miles northeast of Hightown, Highland County, Va. 

C. Milton. 

Bentonite___ _ __ _ ________

JTH-2. 

Volcanic tuff, 7 feet above the 

base of the Martinsburg 

shale near Strasburg, Va. 

J. T. Hack. 

Metarhyolite of Catoctin formation. 

Pa-Sm-fr. 

South Mountain, Franklin 

County, Pa. 

R. S. Cannon.

54J-1. 

U.S. Highway 211, 1.6 miles 

west of Sperry ville, Va. 

H. W. Jaffe. 

Gray granodiorite gneiss. _____

VR-1. 

One and seven-tenths miles 

west of Sperry ville, Va. 

R. S. Cannon, H. W. Jaffe, 

K. J. Murata, G. Neuerberg, 

and G. H. Espenshade. 

Old Rag Granite ________

OR-1.

Mineral

Zircon..___ _ __

___ do _____

___ do _____

-_..do_ .__

 _.do __ -

Mesh size

-80+200 

-200+400 

-100+400

-100+200

-100+200 

-100+200

-80+200

a per mg 

perhr

23 

106 

37

686

854

8,786 

533 

530

725 

1,133

Deter

7

2
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 115

o 

fi

O-6 

I

 s<5

 3*- 111

PM

fi O

ft ft

8 8

(N

o

CO 

(N

00

3

T 1

«5

CD

CO

t^ oc

CO tf.

CO

) C

> u:

<M

^

2

cq ? 

) 1O >O

« ^

w p"

CM

CO

o

CO 

00

cT

55

O 

O

CM

o o

o o

CM CM

+ +

CO 00 I I

s

J .90

3 

o

N

1

8 fr "3 fl r-^ 

S®9

§ 

.PQ

!fi 1

te

son. 

Henderson ga 

54-O1r-207. 

N.C. Rutherford County, 

W. COverstreet. 

Whiteside granit Biotitic 

55Nc-7.

fourths N.C. rs, 

ee- hi

4S

OS sg

3 I? 

H ^

g

(M
Lead-alpha age determinations of accessory minera

No.

277 

278 

279 

280

281 

282

Rock type 

Field No. 

Locality 

Collector

Biotitic Whiteside granite __ _

55-NC-5.

On U.S. Highway 64, north 

edge of Highlands, N.C. 

W. R. Griffitts.

55-NC-4. 

Five miles west of Highlands, 

N.C. 

W. R. Griffitts.

55-NC-3. 

Five miles west of Highlands, 

N.C.

W. R. Griffitts. 

Bessemer granite __ . ________

50L-174. 

Two and six-tenths miles 

northeast of Bessemer City. 

N.C. 

W. C. Overstreet. 

Pegmatite intrusive into Toluca quartz monzonite. 

49-Ot-16. 

Acre rock quarry, Cleveland 

County, N.C. 

W. C. Overstreet. 

Tuloca quartz monzonite_____

49-Ot-14. 

Acre rock quarry, Cleveland 

County, N.C. 

W. C. Overstreet.

Mineral

Monazite_______

Zircon_ ___..____

Monazite _

Mesh size

-80+200 

-80+200

-80+200 

-80+200

-100+200

-100+200 

-100+200 

-100+200

a per mg 

perhr

4,321 

3,909

3,600 

241

620

456 

452

5,685 

450

Determ

7

7

77

1
283

284f

285

286

287

288

289

290

Pegmatite, intrusive into Toluca quartz monzonite. 

53-Ot-14. 

Acre rock quarry, Cleveland

County, N.C. 

W. C. Overstreet. 

Toluca quartz monzonite, late

phase dike. 

49-Ot-22. 

Quarry at Hollis, Rutherford 

County, N.C. 

W. C. Overstreet.

of the type found near Toluca. 

47-Mt-73. 

Eight-tenths mile N.11°W. of 

Toluca, Cleveland County, 

N.C. 

J. B. Mertie.

SOY-328.

Shelbv area, North Carolina. 

R. G.'Yates.

A48-Ot-81.

Shelby area, North Carolina. 

W. C. Overstreet. 

Schist of Carolina gneiss_____

48-Ot-81. 

Shelby area, North Carolina. 

W. C. Overstreet.

50-Y-538.

Shelby area, North Carolina. 

R. G. Yates. 

Schist of Carolina gneiss ___

50-Ot-441. 

Shelby area, North Carolina. 

W. C. Overstreet.

Monazite _ ____

Zircon. ________

Monazite __ ___

Zircon. ________

Zircon. ________

Monazite _ ____

Monazite _ ____

-100 + 200

-100+200

-100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

100 + 200

5,464

652

7,068

6,666

231

4,583

257

5,298

233

4,660

4,573

1

1

1

1,
Lead-alpha age determinations of accessory minera

No.

291 

292

293 

294 

295

296

Kock type 

Field No. 

Locality 

Collector

Homogeneous foliated Cranberry gneiss, saprolite. 

C-l. 

Spruce Pine district, North 

Carolina. 

W. R. Griffitts. 

Homogeneous foliated Cranberry gneiss, saprolite. 

C-2. 

Spruce Pine district, North 

Carolina. 

W. R. Griffitts. 

Granitoid band in augen gneiss. 

RG-2. 

Dellwood quadrangle, Haywood County, N.C. 

R. Goldsmith. 

Mica schist of Carolina gneiss. _

55NC 2 

On U.S. Highway 64, 6.3 miles 

east of Franklin, N.C. 

W. R. Griffitts. 

Max Patch granite.. _________

MP-1. 

Lemon Gap quadrangle, Max 

Patch Mountain, Tenn. 

R. Goldsmith, D. Carroll, 

R. B. Neuman. 

Arenite. _ ___________________

RN-2.

Ocoee series, Great Smoky 

Mountains, Gatlinburg 

quadrangle, Tennessee. 

R. B. Neuman.

Mineral

Zircon. _ _______

_.___do_________

__ do.

_ do __

_ _do.________

Detrital zircon 

(fresh), 

(metamict).. _

Mesh size

-80 + 200 

-80+200

-80+200 

-200+400

-60+200 

-80+200

-80+200 

-80+200

a per mg 

perhr

90 

38

457

472

129 

218

78

124

287

Determ

7

1
LEAD-ALPHA AGE DETEEMINATIONS OF IGNEOUS MINERALS 119

COto

0

o

n

o

ft

* o

ft oft o

ft

Is-" rj .&

 c'G-

°*° 

T'ccW

o o

«-- o

 I O>

00 l> 

US O

a> a> 

»o o

(N

CO CO 

O5

o

00o"

o

o

CO

o o

<N <N

o

o

<N

O 

O

O 

CO

o o

CO CO §

O 

COI

o

CO

 3*1 a

I61

a 

o 

o 

.53

1§i

a ^ M OJ t, OJ aj a

. .» *@ a

«^ »

J

^<N 3 . S«-i (B O 

Cj g>g

^PnO

O QJ

-^> a 

OH

« S .2J-S

 g

o

<u Q o a

SH

"S a

S' .w C bD .93*;; a

. o .g a

M sf

.ills

.Q-C

fl m - aj ..08 «|> fl

«sl§| 5J -r .51- 5

2w ^

'S I ® *

«<P50

1^ l)| I: 

PiP^HP^

i>

o>

(M

CO 

O5 

<N

i

(N

O 

§

§ 

CO
Lead-alpha age determinations of accessory miner

No.

303

304 

305 

306

307

Rock type 

Field No. 

Locality 

Collector

TB56-11. 

Pegmatitic nest, border of 

ilmenite norite and anorthosite, coordinates Y 21536 

and X 37057, Tellenes, 

Hange i Dalane, southern 

Norway. 

T. F. W. Earth. 

Pegmatite ___ ____ _________

TB-1. 

Melkodoela, Bygdin, southern 

Norway. 

T. F. W. Barth. 

Pegmatite

56-1. 

Stjerno, Finmark, southern 

Norway. 

T. F. W. Barth. 

Pegmatite. _ ____ ______

TB-3. 

Dike in basic igneous rock, 

Skarvaan, Seiland, northern 

Norway. 

T. F. W. Barth.

TB-6. 

Dike in igneous basic rock, 

Skarvbergnes, Seiland, northern Norway. 

T. F. W. Barth.

Mineral

_____do________-

do

_____do_-_______

_____do-_----_

Mesh size

+ 60

+ 60 

+ 60 

+ 60

+ 60

a per mg 

perhr

86

211 

27

88

31

Deter
308 

309

310 

311 

312

313

»I

Sovite.. _ ___ ___ _-__ - --

TB-8.

Fen area, southern Norway. 

T. F. W. Barth.

TB-2. 

Dike in migmatitic gneiss, Fen 

area, southern Norway. 

T. F. W. Barth. 

Granite _ ____ __----_-----

EI-1.

Rovaniemi, Finland. 

E. Ingerson.

EI-2.

Salonenkala, Finland. 

E. Ingerson.

EI-3. 

Bodom, Finland. 

E. Ingerson.

Z-61. 

Z-^Sa. 

Z-l. 

Z-3. 

Z-2. 

Z-2L. 

Z-4. 

Z-4a. 

Z-Sb. 

Z-Sc. 

Z-63. 

Z-63L.

Intrusive into Quanah granite, 

Quanah Mountain, Wichita 

Mountains, Okla. 

F. L. Hess, R. L. Dott. 

Jean lead-alpha age (Oklahoma zircon) of 1

---_.do_-__ ..

_. -__do.__ .._...

---.do.____..__

-___-do -__ _

Zircon (metamict) 

Th:U=0.3

r 9 <\7<\

fc=1.77X10-*

Zircon (fresh) 

Th:U=3 

c=2,350 

k -1. 22X10-*.

Zircon (metamict) 

Th:U=4 

c=2,300 

fc=1.12X10-*

To. 313 Is 619 millions of

-60+200 

-60+200

-60+200 

-60+200 

-80+400

30 mm

crystals.

rears.

102

57

303 

374

160

150 

146

157 

184

168 

170 

326 

151 

1,103 

1,292 

1,220 

1,270 

1,180 

1,230 

1,190 

1,168

19, 20, 
Lead-alpha age determinations of accessory mineral

No.

314 

315

316

Rock type 

Field No. 

Locality 

Collector

Tishomingo granite, porphyritic granite. 

Ten Acre Rock, 8 miles northwest of Tishomingo, Arbuckle Mountains, Okla. 

W. B. Hamilton. 

Gem-bearing gravels presumably derived from pegmatite-Ceylon. 

Z-l. 

Z-2. 

Z-4-33. 

Z-3-16. 

Z-5-1. 

Z-4-36. 

Z-3-11. 

Z-3. 

Z-3-42. 

Z-2-37. 

Z-2- 13. 

Z-4. 

Z-2-18. 

Z-2-23. 

Z-6. 

Z-2-17. 

Z-7. 

Z-9. 

Z-l-2. 

Z-10. 

Z-l-26.

G-2117.

Mineral

Zircon_________

Zircon 

Th:U=<0.1 

c = 2,632 

fc=1.9X10-*.

Mesh size

-60+400

Large 

crystals.

-60+200

a per mg 

per hr

72 

80

103 

273 

150 

352 

380 

430 

533 

643 

649 

652 

850 

882 

913 

985 

1,185 

1,245 

1,583 

1,815 

2,040 

2, 197 

2,210 

344 

358

Determ
317

318

319

320

321

322

Tambane, Nyasaland, Africa.

C. E. Tilley.

T-l.

Tambane, Nyasaland, Africa. 

C. E. Tilley. 

Pegmatite ___ ______ _.__

62081. 

Tambane, Nyasaland, Africa. 

C. E. Tilley. 

Fayalite ferrohedenbergite

granite. 

H-3. 

Cranberry Lake quadrangle, 

Adirondack Mountains, N. 

Y. 

A. W. Postel. 

Hawkeye granite gneiss______

P-3. 

Mud Lake Mountain quarry, 

Loon Lake quadrangle, Adirondack Mountains, N.Y. 

A. W. Postel. 

Lyon Mountain granite _ ____

P-l.

Adirondack Mountains, Dannemora, N.Y. 

A. W, Postel. 

Hornblende microcline plagioclase granite gneiss. 

188. 

One hundred seventy-five 

yards southwest of Stone 

school, Russell quadrangle, 

Adirondack Mountains, N. 

Y. 

A. F. Buddington.

-____do______._.

Monazite _ _ _

Zircon ________

_--_.do,-_--_._-

-___do_.____,__

-____dO----__-_

+ 60

+ 60

-60+200

-60 + 200

380

489

185

375

1,634

73

185

187 

215

213

285
Lead-alpha age determinations of accessory minera

No.

323 

324 

325 

326

Rock type 

Field No. 

Locality 

Collector

191. 

Stark complex, 1.5 miles westnorthwest of Coldbrook 

school, Stark quadrangle, 

Adirondack Mountains, N. 

Y. 

A. F. Buddington. 

Pyroxene hornblende granite 

gneiss. 

124. 

Garnetiferous granulite facies, 

Tupper Lake quadrangle, 

Adirondack Mountains, N. 

Y. 

A. F. Buddington. 

Paragneiss. ______ __________

229. 

Seven-tenths of a mile northeast of road to Golden Beach 

on Raquette Lake quadrangle. Adirondack Mountains, N.Y. 

A. F. Buddington.

248. 

Raquette Pond, southwest end 

of Tupper Lake, Adirondack Mountains, N.Y. 

A. F. Buddington.

Mineral

_ __do__ _ -___

 _do_ _.

-__._do________-

Mesh size

-60 + 200 

-60 + 200 

-60 + 200

a per mg 

per hr

188 

101 

130 

134

Determ
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 1 25

O

n

O

n

O

n

O

n

O

n

O

Q

CO Oi

ooo

CO

(NO CO

-^ Oi 0 00 J>

ftrt* GO iO <N rH

1>O i-H <N <N <N

3 O O O O

 1 OS OS OS to

+ + + +

3 O O O

D CO CO CO 1 1 1

1J

§| i ^a g

3 S

38. 

Oswegatchie Adi- quarangle, N.Y. rondack Mountains, 

A. FBuddington. Hornhlftndft eranitft

C O

T3 T:

42. 

Oswegatchie Adi- quarangle, N.Y. rondack Mountains, 

A. FBuddington. 

Pyroxene syenite gneiss. __ 

58SA. 

Lake Tupper quadrangle, Adi- rondack Mountains, N.Y. 

A. FBuddington. Hornblende granite

c

251. 

Cat Pond, Rad northof cut

Lake Tupper quadrangle, AdMountains, irondack N.Y.

A. FBuddington. 

Metamorphosed limestone atwith intrusive contact quarz

00 O O T-I

 < N <N CO CO

0 CO 00 CO 00

syenite. 

6-37. 

Ashmore Farm, 1 mileeast- Natural northeast Bridge, at 

Lake Bonaparte quadrangle, Adirondack Mountains, 

N.Y. 

A. Buddington, H.ol- FD

land.

GO

r-i

O

O

-]-

o

7

c

T:

.2'e

<u

fe

N -+J

Z

3

O

P-4.

Goodnow Mountain quarry, Clara SantAd- quadrangle. 

irondack Mountains, N.Y. 

A. W.Postel.

<N

CO

CO
Lead-alpha age determinations of accessory minera

No.

333

334 

335

336 

337

Rock type 

Field No. 

Locality 

Collector

Hornblende microperthite 

granite. 

B-36. 

Cranberry Lake quadrangle, 

Adirondack Mountains, 

N.Y. 

A. F. Buddington. 

Olivine quartz syenite_____._.

P-2.

Ausable Forks quarry, Ausable Forks, Adirondack 

Mountains, N.Y. 

A. W. Postel. 

llmenitic magnetitic pyroxenic 

shonkinite. 

4973. 

Diana complex, 1,6 miles south 

of Harrisville bridge, Adirondack Mountains, N.Y. 

A. F. Buddington. 

Hornblende granite gneiss____

244. 

One and one-tenth mile eastnortheast of road junction 

to Rainbow Falls, Stark 

quadrangle, Adirondack 

Mountains, N.Y. 

A. F. Buddington. 

Hornblende microperthite 

granite. 

79. 

Big Moose quadrangle, Adirondack Mountains, N.Y. 

A. F. Buddington.

Mineral

Zircon (metamict) .

Zircon. ____ ___

-_...do_. __.. __

____-do... ______

Zircon (metamict).

Mesh size

-60+200

-60+200 

-60+200

-60+200 

-60+200

a per mg 

per hr

293 

325 

435 

460

165 

157

42 

185

310 

615

Determ

52

1

1
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 127

-a GO

o

ft o 

Q Q P

91-'

a 02

£g' '"i to

TS "3

3-s

CO Oi *O CO f~4 C*3 00 00 CS O5 ^t^ C5 ^t 

CO CO CO CO CO iO*O lOCD^CcDCOCO

(N i-»r-l

CO

T-t

rH

cOCDI>T-tOlO5COOO

05 

O 

CO

00a>

OXNOOOO

CO <* t-O CO "5

«-TiH-eo"

o

o

o

0

o

CO

O

CO

o

o

<N

O

CO

S bD «

.8 gS -2 |'3

!

-s"

i

osowj- o >)

O rPl«^fll».-S H-tfldJ 1" We

11! !!!i A

8|h|S«^l48s^

QMM S P<(N m (B .tn (N Sj <£ S^<iw 2^<i

o

JZJ

s

i!

3g|

- £ <u

^> 

O

aT

s-i

S XT3 

0^73 

^ O g ^O P

. .|&! 'co^acQ 

<j.-BPlfSq

£^S° ^i -**-** ^> ^

CO 

CO 

CO

o

CO

co

CO
Lead-alpha age determinations of accessory minera

No.

345 

346

347

348 

349 

350

Rock type 

Field No. 

Locality 

Collector

Granite___ ___________ ___

4B-48. 

Wet Mountains, Colo. 

8. D. Singewald, M. Brock, 

ranite gneiss_______________

4B-50. 

Paragneiss, orthogneiss, or 

granitized rock, origin uncertain, Wet Mountains, 

Colo. 

Q. D. Singewald, M. Brock. 

Granite porphyry. ___________

Co-R-Sl. 

Park Range, Slavonia, Routt 

County, Colo. 

R. S. Cannon. 

Pegmatite __ ___ ____ ____

Co-R-Goo. 

Park Range, Routt County, 

Colo. 

R. S. Cannon. 

Granite __ ______ __________ Wy-F-GM-g. 

Grannier Meadow, Fremont 

County, Wyo. 

R. S. Cannon. 

Graywacke __ _ ____________ Wy-F-MD-GW. 

Miner's Delight, Fremont 

County, Wyo. 

R. S. Cannon.

Mineral

Zircon _ ______

Zircon (metamict) .

Zircon. ________

Xenotime____ _

Zircon (metamict) .

_.___do_________

Mesh size

-80+200 

-80+200

-60+200 

-80+400

-80+400 

-80+400

-80+400

apermg 

per hr

74

176 

213 

232

164

1,749 

2,390

174 

140

Dete

5

1, 25

1, 55
351

352

353

354

355

356

357

Quartz monzonite_____ ___ __

EDJ-1.

Intrusive into Stillwater complex, Mouat mine area,

facies of the Cooke granite,

Stillwater County, Mont.

E. D. Jackson.

Titaniferous black sandstone

of the Late Cretaceous

Mesaverde formation.

GC-W.

Grass Creek area, Wyoming.

J. F. Murphy, R. S. Houston.

Titaniferous black sandstone

of the Late Cretaceous

Frontier formation.

B-l.

Cumberland Gap area, Wyoming.

J. F. Murphy, R. S. Houston.

Titaniferous black sandstone

of the Late Cretaceous

Ericson sandstone.

RS-1.

Rock Springs area, Wyoming. 

J. F. Murphy, R. S. Houston.

Granitic gneiss__-__-_----- _

55ID-60.

Mineral Hill district, Lemhi

Coupjy, Idaho.

E. P. Kaiser.

Oranitic gneiss.----- ____ 

55ID-52.

Mineral Hill district, Lemhi

County, Idaho.

E. P. Kaiser.

Granulite

55ID-55.

Mineral Hill district, Lemhi

County, Idaho.

E. P. Kaiser.

do

Detrital zircon

(white and

purple grains).

Detrital zircon

(white variety, only).

Detrital zircon

(purple alone).

Zircon. ________

do

do

-80 + 200

-200+400

-100+400

-100+400

-100+400

-60+200

-60 + 200

-60+200

167

179

178

218

115

220

247

72

12

13

8. 
Lead-alpha age determinations of accessory mineral

No.

358 

359 

360

361 

362 

363

Rock type 

Field No. 

Locality 

Collector

Granitic gneiss ______ ___ ___

55ID-51. 

Mineral Hill district, Lemhi 

County, Idaho. 

E. P. Kaiser. 

Granodiorite. _ _ _ ___ ___

AND-2. 

Prescott quadrangle, south of 

Prescott, Ariz. 

C. A. Anderson. 

Quartz diorite___________

AND-1. 

Five hundred to one thousand 

feet east of bridge on Ash 

Creek, Cherry Creek road, 

Mingus Mountain quadrangle, Arizona. 

C. A. Anderson. 

Granite____ ________ ________

II.

Crescent Peak, McCullough 

Mountains, T.28S., R.61E., 

Clark County, Nev. 

R. J. Roberts.

Sandstone.. ________________

HF-1. 

Harmony formation, sec. 15, 

T.31N., R.43E., Antler 

Peak quadrangle, Nevada. 

R. J. Roberts. 

Gray porphyritic hornblende 

granite.

Mineral

Zircon _________

_.___do __ _____

Zircon (metamict) .

_ do

Detrital zircon __

Mesh size

-60+200 

-60+200 

-60+200

-60+200 

-60+200

-80+200 

-200+400

a per mg 

per hr

202 

135 

238

593 

130

102 

115

Determi
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 131

o

n

cJOJ JH

.Q "o3 as*

^ Q) CO

AH

00 300

0 

C£

OS 

-H

Oi C 

« 1 ^

cc

Oi

00 

w

<N CO<-H 

CO rH 

,r

C

oc

rH

C 

1C

rH

 <**

CO CO *&

-J( 

O

O

o

<N

O

o

<N

O

o N

+

<N

+ 

O 

00

(N

O o

CO

1

5

"o

SM

g

> 

N

- i

^> ^^

^ 83

p_1 O

rcS .s

osPn g) .

.

1 §

G o

c .fa

JH G) ^> w t-Cj ^s

r< *S "S S -^ £?"§ s s § ^ c3hH y ^ H § o ,smg

-»o O ~ o> O K2 CO tC -^ 

0) 0) . +a rj ig

*U 

 3 **' 8^3 CO fc-^ 5 «--H lass -4^ ( ) 

-^S-S^ > rt^H g

<S

"tt

a o

o

£-

S

B

1 §

fl C

M J.

S

k-T t^H

c3

Pi Mineral 

Ariz. ity, 

c.

-1-3

d>

a, .

gf 4 O H

N

** O Qi

r^ fl ^

C3 ^ "5

p | ^ ] C

1-c* -2 «3 §

S3 Jf! *S O ^ r

.S * "Sn

rH -4 W F* Q fO

G

1 §1

»H H kj ^ Q

o>

^J J~«*H t»-i ^-1 fj ^"

e^^-i°^§5s

Sr^5

. 

Mou th oSo

os sou 60, ex. ann

^ O B3'3 wO-^ § 

N- «_§ Sb 

«&|-d ^° 5o.-g ".Sfld S

.0.3 ^^o> 8"8 .^a0?^^ . §

 Sa^^s'fl^ ! . .-

--' ' ° P50KH tfo3

:^"-^S § tftf ^^

.

18S. Mo 

J

_l

«:!ll

11

.Hill

CO 

CO

00 

CO 

CO

OS 

CO 

CO
Lead-alpha age determinations of accessory minera

Rock type 

No. Field No. 

Locality 

Collector

370 Oatman Creek granite. _____

OT.

Sharp Mountain mass, Llano 

County, central Texas. 

R. M. Hutchinson. 

371 Sixmile granite________-____-

SM. 

Llano County, central Texas. 

R. M. Hutchinson. 

372 Town Mountain granite ______

TM-3. 

Legion Creek mass, Llano 

County, central Texas. 

R. M. Hutchinson. 

373 Phacolith granite of Wolf 

Mountain intrusive body. 

TM-4. 

Llano County, central Texas. 

R. M. Hutchinson. 

374 Llanite_ _ _ ___ __ _ ___

LL-1. 

Intersection of Llanite dike 

and Llano-San Saba road, 

9 miles north of Llano, 

Llano County, Tex. 

P. T. Flawn. 

375 Big Branch gneiss, migmatitic, 

contains inclusions of Packsaddle (?) schist. 

BB-1. 

Blowout quadrangle, Texas. 

P. T. Flawn.

Mineral

Zircon (metamict) .

-____do______-__

_____do-__ __

__ _ do- ___ .__

_____do_________

Mesh size

-60 + 200

-60+200 

-60+200

-60+200 

-80+200

-80+200

a per mg 

per hr

552 

535

629

220 

244

163 

25

101

Determ

9
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 133

o

n &

£*a ft .

$3 o^ 1^

05 is in in

O

o

IN

§ T

eo o

§£

Tex

quadrang 

awn. 1H§503 o!

OB.S "sSS . S S<N| -S»rt ' 

bpjp^ 0 H g ^-c.

S PHfflfcOAHfl

.j, 0^

ft

CO

eo

i>

CO

00 

CO

o

00 

CO
Lead-alpha age determinations of accessory miner

No.

381 

382

383 

384

Eock type 

Field No. 

Locality 

Collector

NM-1. 

Birthday area north of Sulphide Queen carbonate 

body, Mountain Pass, San 

Bernardino County, Calif. 

T. B. Nolan, W. T. Pecora. 

Barite carbonate rock ______ _

SQ-81. 

West edge of Sulphide Queen 

carbonate body near its contact with gneiss, Mountain 

Pass, San Bernardino County, 

Calif. 

D. F. Hewett, D. R. Shawe. 

Biotite-rich inclusions in the 

Mesozoic intrusive rocks of 

the Moiave Desert. 

ZC. 

Conkey Claims, Yucca Valley, 

San Bernardino County, 

Calif. 

D. F. Hewett. 

Ashokan flagstone ___________

NY-Da-56-J-24. 

Ashokan formation of the 

Hamilton group, new road 

cut on New York route 32, 

west of Quarryville, Catskill-Kaaterskill quadrangles, New York. 

H. W. Jaffe.

Mineral

Zircon (metamict) .

Monazite 

Th:U= 1,300 

c=2,013 

k =0.6X10-*.

Zircon (metamict) .

Detrital zircon 

(composite of 

white and 

purple crystals). 

(White crystals alone).

Mesh size

-60+200 

+ 60

-60+200

-60 + 200

-60 + 200

-60+200 

-60 + 200

a per mg 

per hr

270 

300 

600 

1,220

2,200

569 

3,818 

2,369

85 

90

Deter
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 135

2 s

1°

o

ft oft

00 _ _ c>

rH OCOl> OS 

O

CO

"*

IN"

O O 00 iO O 

CO Tp<Ni-H CO

o

+

o

5

p3 **"*

2° t

 3-l'gB

-ft*^

J aH +=> 

-

§1%

s ffl

SJQ!

~ M a

f-e o3

c8

, s 0)0*

 2 g

<N gK

S's"!

pj 03

<5OO>n O

CO 

00 

CO

00

00 

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O5 

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Lead-alpha age determinations of accessory miner

No.

392 

393

394

395 

396

397

Rock type 

Field No. 

Locality 

Collector

Rhyolite_ _____ _ __________

3094. 

Copper Cliff rhyolite, Frood 

mine, McKim Township, 

Ontario, Canada. 

P. M. Hurley, H. Fairbairn.

GS-2-36-55. 

From Archean injection gneiss 

or migmatite, Yamba Lake, 

Northwest Territories, 

Canada. 

R. E. Folinsbee.

HJ-47-54. 

From gabbro-red rock complex 

of Keweenawan age, Mellen, 

Wis. 

H. L. James. 

Quartz-zircon pegmatite, floatWM-124-53. 

Sec. 23, T.29N., R.6E., Marathon County, Wis. 

R. C. Vickers. 

Granite gneiss. _____________

HJ-43-54.

NEJi sec. 7, T.42N., R.28W., 

central Dickinson County, 

Mich. 

H. L. James. 

Granite__._____ __ _ ______

KW-120-54.

Mineral

Zircon 

(metamict) .

Monazite 

Th:U=21 

c=2,100 

k = 0.68X10-*

Zircon 

(metamict) .

_-___do__---___-

_____do_________

Mesh size

-80 + 400 

-80 + 400

-80 + 200

Large 

crystals.

-80 + 200 

-80+200

a per mg 

per hr

56 

4,339

103 

101 

100

952 

680

610

Dete
398

399

400

401

402

403

404

NEK sec. 21, T.42N., R.32W., 

Iron County, Mich. 

K. Wier.

HJ-44-54. 

NEJ^SWJi sec. 22, T.41N., 

R.30W., central Dickinson 

County, Mich. 

H. L. James.

KW-126-54. 

Roadcut, 1.2 miles north of 

Randville, SW^NE^ sec. 

28, T. 42 N., R. 30 W., 

Dickinson County, Mich. 

K. Wier.

1101-A. 

Active quarry, 5 miles south 

of Isle, Minn. 

R. G. Schmidt.

FS-2. 

Upper Minnesota River valley, Minn. 

G. M. Schwartz. 

Porphyritic granite _ ___ ____

SG-5. 

Cold Springs granite quarry, 

Rockville, Minn. 

G. M. Schwartz. 

St. Cloud gray "granite",

(granodiorite). 

FS-1. 

St. Cloud, Minn. 

G. M. Schwartz. 

Granite__ _ ______-_-___--_

SG-4. 

Giant's Range, Embarass batholith, Babbitt, Minn. 

G. M. Schwartz.

__-_-do___ __ __

mict) . 

__-.__do_________

_____do __ _ __

_ __do _____ _

Zircon. _______

-80+400

-80+400

-80+400

-80+400

-80+200

-200+400 

-80+200

-80+200

-200+400

808

99

610

253

230

250 

866

165

177

1

1
Lead-alpha age determinations of accessory minera

No.

405

406 

407 

408 

409

410

Rock type 

Field No. 

Locality 

Collector

SG-1. 

Giant's Range batholith, 

quarry north of Mount Iron, 

Minn. 

G. M. Schwartz. 

Hillman tonalite_ ____________

1204. 

Sec. 10, T.40 N., R. 30 W., near 

Pierz, Minn. 

R. G. Schmidt. 

Quartz ruonzonite _ ___ __

1100. 

Myer's quarry, sec. 13, T. 40 

N., R. 31 W., Pierz, Minn. 

R. G. Schmidt. 

McGrath gneiss __ _________

1203. 

Sec. 12, T. 43 N., R. 24 W., McGrath, Minn. 

R. G. Schmidt, 

Granite _ ___ _ _____________

SG-2. 

Border phase of Saganaga 

batholith, sec. 22, T. 65 N., 

R.4 W., Gunflint Trail, Minn. 

G. M. Schwartz. 

Granite __ _ ___ ______ _ _

M-3655. 

Interior mass of Saganaga 

batholith, Sea Gull Lake, 

east side of Cucumber Island, 

NWJ4 sec. 12, T. 65 N., 

R. 5 W.,Cook County, Minn. 

G. M. Schwartz.

Mineral

Zircon (metamict) .

_____do_________

Monazite _ ____

Zircon (metamict) .

Zircon. _ _______

____-do______-._

Mesh size

-80+200 

-200+400

-80+200 

-80+200 

-80+200

-80+200 

-200+400

-80+200 

-200+400

a per mg 

per hr

393 

420

360 

3,858

318 

353

104 

95

63 

62

Determ

23

22

20

22

25

57, 
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 139

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fi

oco

O v Tn fl .3

jeo- 

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OS£ 0
140 STUDIES IN1 GEOCHRONOLOGY

Geographic index of localities

Locality No. 

British Territories in Borneo 

West Sarawak 

Bau__________________________________________ 46

Sebuyau.. __________________________________________ 190

Tanjong Datu____--_ ___--___---_-__-_-___---______________ 47

Tenting, Bedil_________..._______________________ 189

Canada 

Alberta

Carbon__ ___________________________________________________ 54

British Columbia

Lower Arrow Lake district________ __ ____ _ _______________ 176

Washington-British Columbia border____-_-____-____-___. ______ 175

Manitoba 

Snow Lake-Herb Lake area._- ____________,...___-_-_-__________ 391

New Brunswick

St. George.._____________________________________ 243

Pocologan Harbor______________________________________________ 244

Northwest Territories

Yamba Lake__________________________________________ 393

Ontario

Burgess County _____________________________________ 388

Essonville..._______________________________________________ 389

Frood mine,.__________________________________. ______ 392

Renfrew County____--__-_____-___--____-_-.___-____-____ 386, 387

Quebec

Montreal...____________________________________ 220

Ceylon____________._____________________________ 315

Finland

Bodom__________________________________________ 312

Rovaniemi____________________________________________________ 310

Salonenkala___________________________________________________ 311

Formosa

Northern Formosa________________________________________________ 48

France

Vosges Mountains_______________________________________________ 192

Greenland 

Thule area_____________._________--,_-_____-__________._ 390

Mexico

Baja California______._____________ _______ 79, 80, 81, 82

Chiapas

Calzada Larga________________________________________________ 191

Guerrero

Acapulco. ________ _ ____ _____ _ __- 85

El Ocotito ________________--______-_____-_ 83

Placeres__________________________________ 86

Xaltianguis___________________________________________________ 84

Morelos

Huajintlan__________________________________________________ 12

Oaxaca 

Huilotepec__________-______-___-----_-___ ________________ 87

Jalapa____-__ -_ ____ __ -- __ 88

Norway 

Barkevik_____----.-_-_____-___-_-__..__...._...._ _. 184, 187

Djupdalen_______________________________ _______ __ 186

Fen area___.____________________.__-_.-__--__.__-_____--- 308, 309

Larvikofjorden_____________________--_--___-_-------_-----___--- 182

Laven___________-___-_______-___-_---_-__--------__--_-_-_--- 185

Melkodoela-.------ ---_-------------- -- 304

Meyerfjord_____ _._ - -- -------- 188

Skarvaan_ ________ ________ __ _-_ _ 306

Skarvbergnes_____ __ -.. -- -- -- 307

Stjerno________-__-_-_____--____-__-__--__.------------- 305

Tellenes _-- -__ --- - ---- - - - 302,303

Tveitdalen___-_______________- .-__ -_ ---- ... 183
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 141

Locality No. 

Nyasaland 

Tambane__.____________________________.._ 316, 317, 318

Puerto Rico 

Humacao__-_-_____-_-_-___---____________-_______--_-_____-_- 62

Limones _ _____________________________________________________ 61

Saudia Arabia

Dhalm____________________________________________________. 197

Eastern batholith_____..___-______________________________ 194

JebalRafa____________________________._______ 193

JebalZ'aba_____________ ________._____________ 195

Taif___________________________________________________________ 196

United States 

Alaska 

Flat area.________________________________________ 50, 51

Fortymile district________-__________-__________--_-____-_--__ 177

Kuskulana River area________________________________________ 180

Nixon Fork mining district.- ___________________________________ 53

Prince of Wales Island.__--___.________________________ 179

Ruby-Poorman district_______________________________________ 52

Turner Lake_________________..________._____________ 178

Arizona

Mineral Park_____________________________ 366, 367

Mingus Mountain quadrangle________________________-______-___ 360

Prescott quadrangle__________________________________________ 359

San Manuel________________________________________________ 181

California 

Bishop area

Big Pine quadrangle,._______________________ 123, 124, 126, 127

Mount Goddard quadrangle.__ _____________________________ 121, 125

Mount Tom quadrangle..______________________________ 122, 128

Kern River area____-_____-_______-_____-_---___-___-________ 130

Shasta County

French Gulch quadrangle______-___-_-_____-_______-_-___- 134, 135

Southern California

Aquanga___________________________________________________ 89

Apple Valley______________._--____-________-_-_--_-__- 117

Berdoo Canyon. ____________________________________________ 118

Cottonwood Springs.________________________________________ 119

Cuyumaca quadrangle-_-----_-__-__-___--_--____-__-_------- 109

Descanso Junction___________________________________ 100, 103, 104

Elsinore.-._______________________________ 105

Green Valley__________________________________. 90, 91

Ivanpah quadrangle_________________________________________ 115

Lakeview_______________________________________________ 94

La Posta___________.________________________ 97

Mount Hole-.._-_____________________________ 101 

Mount Wilson__________________________________ 98

Mountain Center__________________________________________ 93

Mountain Pass_______________________ 379, 380, 381, 382

Neenach quadrangle.________________________________________ Ill

Nuevo..________________________________ 99

Palm Springs_______________________________-._____-__ 92

Perris_______________ _______________________________________ 95

Pomona Tile quarry.________________________________________ 110

Providence Mountain__-__--____-__-______-______-___________ 112

Rosamond quadrangle______________________________________ 114

Rubidoux Mountain_-_____-_______________________________ 107, 108

Shadow Mountains__________________________________________ 120

Soda Lake_______________________________________________ 113

Stonewall Mountain________________.________________________ 102

Temecula_______________________________________________ 106

Twenty Nine Palms___________________________________ 116

Valverdi___________________________________________ 96

Yucca Valley...._______________________________ 383
142 STUDIES IN1 GEOCHRONOLOGY

Locality No. 

United States Continued

California Continued

Ubehebe quadrangle.__________________________________________ 129

Yosemite National Park________________________________ 131,132,133

Colorado

Iron Hill_____________._______ _________________ 343

Park Range.__________________________________________ 347, 348

San Juan Mountains_-______---___---_--_--_-_-__ 1, 2, 3, 4, 5, 6, 7, 8, 9

Wet Mountains.-___--_____-_-____--___-_--__-_-_---_- 344, 345, 346

Connecticut

Moosup______________________________________________________ 210

Idaho

Atlanta. ___________________________________ 151

Big Creek quadrangle______________________________ 144,145,146

Bungalow. _________________________________________ 141

Camas Creek____________________________________________.____ 56

Cascade_-_-___-__________________________-___________________ 143

Coeur d'Alene district______________________________________ 159,160

Craters of the Moon.__________________________________________ 78

Garden Valley. ________________________________ 153

Hailey.______________________________________________________ 148

Horseshoe Bend.______________________________________________ 147

Idaho City_____________________________________ 155,156, 157,158

Lowman_______________________________________________ 55

Mineral Hill district.._____...____.____ 161,162,163, 355, 356, 357, 358

South Fork Payette River_________________________ 142

Placerville.___________________________________________________ 154

Powell.._______________________-__-__________-_____ ____._ 152

Quartzburg district.___________________________________________ 139

Salmon River._____________ __________________________________ 140

Stanley_______-____________--_---_-_____---___--__-_-_---_ 149,150

Maine 

Northern Maine

Brassua quadrangle__-____-___-____---_---__-------__-_____ 242

Jackman_____________________________________ 239,240

Ripogenus dam____________________________________________ 241

Southern Maine

Wells_-_______________________________________--_-._.______ 238

Maryland 

Great Falls. _____ ___ __________.____________ 272

Massachusetts 

Peabody____________________________________ 205

Michigan

Dickinson County_________________.__________ 396, 398, 399

Iron County.______________.____.________-__._-___ 397

Minnesota 

Babbitt.-.__________________.-_______________ 404

Gunfint Trail__._.__________________.________ 409

Isle_________-__-_-.__-_________-____--___--____-_--__-__--_.. 400

McGrath_________________________________________ 408

Mount Iron_________________________________________________ 405

Pierz_______________________________________ 406,407

Rockville_______________________________________ 402

Sea Gull Lake. _ __ _ _ . 410,411

St. Cloud________________________-_--__----------__-----. 403

Upper Minnesota River valley._______-_-__-_--_-_-----_-_----__ 401

Montana

Bearpaw Mountains_________________-______--_-__--_____--__-_ 44, 45

Boulder area____________________-_____ 66, 67, 68, 69, 70, 71, 72, 73, 74, 75

Garrison___ _ ______________________---_-__----_---------_---_ 64

Hamilton________________________________-__ 57, 58, 59, 60

Philipsburg ____________________________-_-_---__-------__----_ 63

Stillwater County._________________-________________ 351

Tobacco Root Mountains________-___--_-----------------_---_- 65
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 143

Locality No. 

United States Continued 

Nevada

Antler Peak quadrangle--_-__-________________---_--___--_-__-- 362

Austin..________________.___.________________ 29

Bloody Run Peak_-__.__-__________________.__----- 37

Boulder City_________.______________.____________ 34

Copper Canyon.___-____-_______-_________-___-_-------------- 31, 32

Crescent Peak____________________________-_-------_-___ 361

Eureka mining district..._____________________________ 26, 27, 28

Mount Lewis and Crescent Valley quadrangles.__________-_-_._-__ 41

Nelson________________________________________ 33

Osgood Mountains___________________________________________ 77

Santa Rosa Peak._____________________________________________ 35

Slumbering Hills._____________________________________________ 36

Trenton Canyon_____________________________________________ 30

New Hampshire

Belknap Point-.. _ __._ - __ 213, 221 

Cardigan quadrangle_______________________.___ 223, 227, 228

Concord_____________________________________ 226

Exeter. _________________________._______..____- 230

Franconia quadrangle.________-____________-_--_-_----__------- 215

Hanover quadrangle-._______________________ 235, 236, 247

Lancaster__ ___-____-__-_-___-_____________-_--_--_--------- 248

Lisbon.________________________________________ 232

Littleton..____________________________________ 231,245

Lovewell Mountain quadrangle__-________-______-----------_-- 222

Martin______________________..__-__-________ 229

Mascoma quadrangle--______-__---_-___-__-__-___--------_-_-- 237

Mount Cube quadrangle________.______________---_-_-_--_---- 246

Mount Chocura quadrangle-___----__-_-_----_-_--_------------- 218

Mount Washington quadrangle__________________---__-_-_-__ 233, 234

North Conway quadrangle______________________________ 214, 216, 217

Percy quadrangle____________________________________________ 219

Rumney quadrangle.__________-_________--_____-.-_-_-_---_-_- 224

Sunapee quadrangle.-___-_-_-__-______-_-____-____-_-_-_---_-_- 225

New Jersey

Beemerville_________._-_-__-__.______________ 249, 250, 251

Dover__________________________________________________ 342

New Jersey Highlands----.--------.-.----------------------- 340, 341

New Mexico

Big Hatchet Peak quadrangle._----__-___--__-__-------------_-- 363

Cerrillos Hills______________._.______________ 25

Hachita quadrangle__________________________________________ 49

Los Pinos Mountains-_________________________________________ 365

Sangre de Cristo Range._-__--_-_-___-__-________-__-__-_--_-_- 364

Santa Fe County..__________________________-____-_-_--_-_.- 10

Valles Mountains______--______-_______-________-_-__-_----__ 13

New York

Adirondack Mountains

Ausable Forks____________.,______________--_______-__--- 334

Big Moose quadrangle.-______-______-__-_._-________-__-_-_- 337

Cranberry Lake quadrangle __-_________________----------- 319, 333

Dannemora. ________________________________________________ 321

Harrisville bridge__________________________________________ 335

Loon Lake quadrangle--______--______-_-_________--_--_-___- 320

Natural Bridge__________________________________________ 331

Oswegatchie quadrangle.___________________________________ 327, 328

Raquette Lake quadrangle_---______________..-_-_-_-_--_-_-_ 325

Russell quadrangle_________________________________________ 322

Santa Clark quadrangle.--__-_--__________-___-________----_- 332

Stark quadrangle..______________________________________ 323, 336

Tupper Lake________.__._.___________________ 326, 339

Tupper Lake quadrangle--------____________-_-_.-_ 324, 329, 330, 338
144 STUDIES IN GEOCHRONOLOGY

locality No. 

United States Continued 

New York Continued 

Catskill Mountains

Quarryville_____________________________________ 384

Stony Cove____________________________________.____ 385

North Carolina

Bessemer City._______________________________________________ 280

Cashiers_____________ _ _ _ _ _ __ ______ _ ___ _ 276

Cleveland County______________________ 274, 281, 282, 283, 285

Franklin__________________________________________ 294

Haywood County______ __ _ _ ____________ _ 293

Highlands..______________________________________ 277,278,279

Rutherford...______________________ _______________ 275, 284

Shelby area_______________________________ 286, 287, 288, 289, 290

Spruce Pine district____________________________________ 291, 292

York County-__.______________________________ 273 

Oklahoma

Arbuckle Mountains.________________________________________ 314

Wichita Mountains.-._____________________________________ 313

Oregon

McKenzie Bridge quadrangle________________________________.__ 24

Medford quadrangle_________________________________________ 137, 138

Mill City quadrangle_________________________________________ 11

Sumpter quadrangle ___________________________________________ 136

Pennsylvania

Easton_________________________________________________ 264

Philadelphia area

Clifton Heights______________________________ 257, 262

East Lake Park___________________________________________ 256

Fairmount Park_______________________________ 253, 258

Springfield_______________________________________ 252, 254, 255

Swarthmore_______________________________________________ 260

West Manayunk_____________________________ 259, 261

Somerton_________________________________________________ 263

South Mountain___________________________________ 267

Rhode Island

Ashaway quadrangle_______________________ 198, 199, 200

Bradford. ___________________________________ 201

Ganier Memorial dam_______________________________________ 207

Georgiaville quadrangle._______________________________________ 209

Narragansett Pier quadrangle.__________________________________ 208

Quaker Lane________________________________________________ 204

Quonochontaug quadrangle _____________________________________ 203

Ten Rod road_.___________________________________________ 206

Tower Hill_____________________________________ 202

Tennessee

Great Smoky Mountains

Calderwood quadrangle__________________________________ 297, 300

Gatlinburg quadrangle.._______________________________ 296, 301

Thunderhead quadrangle.___________________________ 298, 299

Max Patch Mountain__________________________--____________ 295

Texas

Blowout quadrangle_________-________________________-_____- 375, 376

Llano County...______________________ 368, 369, 370, 371, 372, 373, 374

Pecos County_________________________ ______ 377

Schleicher County___________________________________________ 378

Utah

Iron Springs district_________________________--__-_-_--____- 16, 17, 18

La Sal Mountains.._______________________ 19, 20,21,22,23

Sheep Rock Range.__________________________________________ 14

Thomas Range______________________________________________ 15

Tintic district..___________________________________-.-___ 42, 43

Wasatch Mountains..___________________ _______ 38,39,40
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 145

Locality No. 

United States Continued

Virginia

Hightown______________________________________ 265

Shenandoah National Park____________________ 270, 271

Sperryville________________________________ 268, 269

Strasburg______________________________________ 266

Vermont

Mount Ascutney..____________________._________ 211, 212

Washington

Arden______________________________________,_ 166

Chelan quadrangle______________ _ ____________ 168, 169, 172 

Holden quadrangle________________________ 170, 171, 173, 174

Mount Annie._______________________________________________ 164

Mount Rainier National Park_________________________________ 76

Sultan quadrangle_____________________________________________ 167

Tonasket___________________________________ 165

Wisconsin

Marathon County_____________________________________________ 395

Mellen______________________________________ 394

Wyoming 

Cumberland Gap area________________________________________ 353

Fremont County..______________________________ 349, 350 

Grass Creek area_________________________________ _________ 352

Rock Spring area_____________________________________-____._-_ 354

LITERATURE CITED

Anderson, A. L., 1951, Metallogenic epochs in Idaho: Econ. Geology, v. 46,

p. 592-607. 

 1952, Multiple emplacement of the Idaho batholith: Jour. Geology,

v. 60, p. 255-265. 

Billings, M. P., 1956, The geology of New Hampshire, part 2 Bedrock geology:

New Hampshire State Plan, and Devel. Comm., Concord, 203 p. 

Boucot, A. J., 1954, Age of the Katahdin granite [Maine]: Am. Jour. Sci., v. 252,

p. 144-148. 

Bramkamp, R. A., Gierhart, R. D., Brown, G. F., and Jackson, R. 0., 1956,

Geologic map of the Southern Tuwayq quadrangle, Kingdom of Saudi

Arabia: U.S. Geol. Survey Misc. Geol. Inv. Map 1-212A. 

Brown, J. S., 1926, The Nixon Fork country and silver-lead prospects near Ruby

[Alaska]: U.S. Geol. Survey Bull. 783-D, p. 97-150, pis. 5-6. 

Brown, R. W., and Pecora, W. T., 1949, Paleocene and Eocene strata in the Bearpaw Mountains, Montana: Science, v. 109, p. 487-489. 

Buddington, A. P., 1939, Adirondack igneous rocks and their metamorphism:

Geol. Soc. America Mem. 7, 354 p. 

Buddington, A. P., and Chapin, Theodore, 1929, Geology and mineral deposits of

southeastern Alaska: U.S. Geol. Survey Bull. 800, 398 p., 22 pis. 

Butts, Charles, 1933, Geologic map of the Appalachian Valley of Virginia:

Virginia Geol. Survey Bull. 42, 56 p. 

Carroll, Dorothy, Neuman, R. B., and Jaffe, H. W., 1957, Heavy minerals in

arenaceous beds in parts of the Ocoee series, Great Smoky Mountains,

Tennessee: Am. Jour. Sci., v. 255, p. 175-193. 

Chadwick, G. H., 1944, Geology of the Catskill and Kaaterskill quadrangles,

New York: New York State Mus. Bull. 336, pt. 2, 251 p. 

Chapman, R. W., Gottfried, David, and Waring, C. L., 1955, Age determinations

on some rocks from the Boulder batholith and other batholiths of western

Montana: Geol. Soc. America Bull., v. 66, p. 607-609.
148 STUDIES IN GEOCHRONOLOGY

Silver, L. T., Stehli, F. G., and Alien, C. R., 1956, Lower Cretaceous pre-batholithic rocks of northern Baja California, Mexico [abs.]: Internat. Geol. Cong.,

20th, Mexico City, Resumenes de los trabajos presentados, p. 30. 

Smith, A. R., and Stevenson, J. S., 1955, Deformation and igneous intrusion in

southern British Columbia, Canada: Geol. Soc. America Bull., v. 66, p.

811-818. 

Spencer, A. C., and others, 1908, Description of Franklin Furnace quadrangle,

New Jersey: U.S. Geol. Survey Geol. Atlas, Folio 161, 27 p. 

Stearns, C. E., 1953, Tertiary geology of the Galisteo-Tonque area, New Mexico:

Geol. Soc. America Bull., v. 64, p. 459-507. 

Stenzel, H. B., 1932, Pre-Cambrian of the Llano uplift, Texas [abs.]: Geol. Soc.

America Bull., v. 43, p. 143-144.

 1935, Pre-Cambrian structural conditions in the Llano region [Texas]:

Texas Univ. Bull. 3401, p. 74-79. 

Tansley, W., Schafer, P. A., and Hart, L, H., 1933, A geological reconnaissance

of the Tobacco Root Mountains, Madison County, Montana: Montana

Bur. Mines and Geology Mem. 9, p. 13. 

Taubeneck, W. H., 1955, Age of the Bald Mountain batholith, northeastern

Oregon: Northwest Science, v. 29, p. 93-96. 

Taylor, C. H., 1915, Granites of Oklahoma: Oklahoma Geol. Survey Bull. 20,

108 p. 

Umpleby, J. B., Westgate, L. G., and Ross, C. P., 1930, Geology and ore deposits

of the Wood River region, Idaho, with a description of the Minnie Moore

and near-by mines, by D. F. Hewett: U.S. Geol. Survey Bull. 814, 250 p.,

33 pis. 

Wadia, D. N., and Fernando, L. J. D., 1944, Ilmenite, monazite, and zircon

(sessional paper 6 of 1926, revised), Gems and semi-precious stones of Ceylon:

Ceylon, Dept. Mineralogy, Recs., Prof. Paper 2, p. 13-44. 

Waters, A. C., 1938, Petrology of the contact breccias of the Chelan batholith:

Geol. Soc. America Bull., v. 49, p. 767.

 1955, Volcanic rocks and the tectonic cycle, in Crust of the earth, Arie

Poldervaart, ed.: Geol. Soc. America Spec. Paper 62, p. 703-722. 

Waters, A. C., and Krauskopf, K., 1941, Protoclastic border of the Colville

batholith: Geol. Soc. America Bull., v. 52, p. 1355-1418. 

Wells, F. G., 1956, Geology of the Medford quadrangle, Oregon: U.S. Geol.

Survey Geol. Quad. Map GQ-89. 

Woyski, M. S., 1949, Intrusives of central Minnesota: Geol. Soc. America Bull.,

v, 60, p. 999-1016.

o