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
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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)
CONTENTSPage
Abstract _____-_-_-_____-__-_________-___________-____-___..-_-_-__ 65Introduction. _ ____________________________________________________ 65Acknowledgments. ______--_-______-_-________-_----____-__-___---.. 66Nature of the descriptive and experimental data_____________________ 67
Method of calculation of the age_--__-_--__--_-------_--_--_--_- 67Reproducibility of the age determination.________________________ 68Arrangement of the data in the tabulation____________________--__ 68
Lead-alpha age determinations of accessory minerals.__________________ 69Geographic index of localities.______________________________________ 140Literature 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 determina tions. 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 sub mitted by State and foreign geological surveys. Ages were deter mined 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 question able 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.
ACKNOWLEDGMENTSThe 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 lead- alpha 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 lead- alpha 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 in consistency of the measured lead-alpha age with the geologic age assigned from stratigraphic, paleontologic, and field mapping investi gations. 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-}4kp1,700 4,000 T=tf-
The constants, c and k are functions of the thorium to uranium rji l.ios of the different accessory minerals xenotime, zircon, and mona- zi 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 strati- grnplilu-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)
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-estab lished 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 lead- alpha 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, which ever 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 be tween the ages of zircon, monazite, and xenotime, separated from the same rock, is of the same order of reproducibility as obtained on dif ferent 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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r hr 19
9
387
520
394
129
365
Lea
d (p
pm)
Det
erm
inat
ions
3. 5
, 4.
0
7. 2
, 8.
0
8.0
5. 2
, 6.
3
2. 1
, 3.
4
5. 3
, 5.
5
Mea
n 3.75
7.6
5. 7
5
2.7
5.4
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears 47
49
38 38 53
37
Cite
d ge
olog
ic a
ge o
f the
ro
ck
No
data
. R
. J.
R
ober
ts.
Do.
Do.
Lat
e C
reta
ceou
s to
ea
rly
Ter
tiar
y.
E.
H.
Pam
peya
n.
Do.
Pos
t-L
ate
Cre
ta
ceou
s (p
re-M
i-
ocen
e).
R.
Wil
l-
den.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 75
i 5op
0
p n P
55
S3'|
H
toOJ
o1 1o"
to<3i
<N 0
tO O5
t>r
toI-Hi-H
C£iH i I
^CO
CO.
r-T
o00 <N
Oo o
o<N
O CO
I
OOoo<N<N
O O <N
OO COCO
I I
.-§«I- Oc o
£s
OiOE 6? i*38i*
t-> CO -f3 OXNtJ
agl^ m gta S3 § M-^tdo fl rto S f^ 2w 3^3^fa«5i §flP5^ !
0) isrtHH ^ 5 to ^S
3
'-C ol^-fl-I
«-i 53 83^f^P 0" ^
Oa $ %2
1 g
jto bCoS
O
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
erals
Con
tinu
ed
No. 42 43 44
45 46
47
Eoc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
HT
M-2
. N
orth
L
ily
stoc
k,
1,25
0 fe
et
N.3
4°W
. of
Nor
th L
ily m
ine
shaf
t,
Eas
t T
inti
c di
stri
ct,
Uta
h.
H.
T.
Mor
ris.
HT
M-1
.S
ilve
r C
ity
stoc
k,
from
ra
il
road
cut
nea
r th
e Ir
on D
uke
min
e, T
inti
c di
stri
ct,
Uta
h.
H.
T.
Mor
ris.
P-5
0-49
. B
ig
San
dy
Cre
ek,
Bea
rpaw
M
ount
ains
, M
ont.
W
. T
. P
ecor
a.
WT
P-3
. R
ocky
B
oy
stoc
k,
Peg
mat
ite
Pea
k,
Bea
rpaw
M
ount
ains
, M
ont.
W
. T
. P
ecor
a.
Dac
ite
.._
____
_ __
____
_
__S.
367
3.
Ban
, 1s
t D
ivis
ion,
Wes
t S
ara
w
ak,
Bri
tish
T
erri
tori
es
in
Bor
neo.
F
. W
. R
oe.
Gra
nite
. _ _
____
____
____
____
__S
outh
368
6.
Min
eral
Zir
con _
__-_
--
__
_-_
do
_ ~
__
_-.
do
_-_
-__
-_-_
-do_--
_.-
_-_
__
__
.do
_ .
.._.
_ .do
Mes
h si
ze
-100+
200
-20
U+
40
0
-10
0+
20
0
-20
0 +
400
-80
+1
00
-1
00+
200
+20
-80+
200
-80+
200
a pe
r m
g pe
r hr 233
228
187
223
290
275
218
227
225
156
Lea
d (p
pm)
Det
erm
inat
ions
4.0
3.6
3.7
4
.5
5. 2
, 5.
G 5.
0, 5
. 1
5.6
4.0
3. 0
, 4.
0 5.
0,
6. 0
3. 0
, 2.
9
Mea
n
5.4
5
.05
4.5
2.9
5
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears 43
39 49
50 46
46 64
44 50
47
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Mid
dle
Eoc
ene
(Gre
en R
iver
).
H.
T.
Mor
ris,
T
. S.
Lev
erin
g.
Do.
Mid
dle
Eoc
ene
(Gre
en R
iver
).
Bro
wn
and
Pec
ora,
194
9.
Do.
Ter
tiar
y.
F.
W.
Roe
.
Ter
tiar
y (?
).
F.
W.
Roe
.
i o S CJ H
48 49 50 51 52
Tan
jong
D
atu,
1s
t D
ivis
ion
Wes
t S
araw
ak,
Bri
tish
Ter
ri
tori
es i
n B
orne
o.
F.
W.
Roe
.
alka
line
bas
alt.
T
PY
-1.
Nor
ther
n F
orm
osa.
T
. P
. Y
en.
4832
45.
Hach
ita
quadra
ngle
, S
EM
NE
M s
ec.
22,
T.2
9S.,
R.1
6W.,
sout
hwes
t N
ew
Mex
ico.
C
. D
ane.
1895
. F
lat
area
, F
lat
Cre
ek
near
S
tran
dber
g ca
bin,
1.
5 m
iles
no
rthw
est
of C
hick
en C
reek
, Id
itar
od q
uadr
angl
e, c
entr
al
Ala
ska.
P
. K
ille
en,
M.
Whi
te.
1810
. F
lat
area
, op
posi
te p
lace
r cu
t on
Chi
cken
Cre
ek,
Idit
arod
quad
rang
le,
cent
ral
Ala
ska.
P
. K
ille
en,
M.
Whi
te.
3469
.
Fli
nt
Cre
ek o
f th
e S
ulat
na
Riv
er,
Rub
y-P
oorm
an
dis
tr
ict,
R
uby
quad
rang
le,
cent
ral
Ala
ska.
M
. W
hite
, J.
Ste
vens
.
....
_do
__ _
_--
___ d
o _
___ -_
% i
nch
crys
tals
.
-80+
200
-200+
400
-60
+1
00
-60+
100
-80
+ 2
00
21 250
275
334
315
1,36
61,
322
1,34
2
.4,.
4
4. 0
, 5.
05.
0,
6. 0
6. 2
, 7.
0
7. 8
, 7.
4
26,2
7 29 30
.4 4.5
5.5
6.6 7.6
26
.5
47 45 50
49 60 48 55 56
f
Pre
-Mio
cene
. ^
T.
P.
Yen
. b
Lat
e C
reta
ceou
s or
j£
Ter
tiar
y.
Las
ky,
^
1947
, p.
32-
33.
o O M
Lat
e or
pos
t-
gE
ocen
e.
Mer
tie
S
and
Har
ring
ton,
fej
19
24.
> o
Do.
§ M Q
O aM
esoz
oic(
?)
(pos
t-
^M
issi
ssip
pian
) .
§M
erti
e an
d H
ar-
fejri
ngto
n,
1924
. g
OQ
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No. 53 54 55
56
57
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
5044
. N
ixon
F
ork
min
ing
dist
rict
, C
ryst
al S
haft
min
e, M
edfr
a qu
adra
ngle
, ce
ntra
l A
lask
a.
J. J
. M
atzk
o, G
. D
. E
berl
ein.
K
neeh
ills
tuf
f _
2415
. V
itri
c-cr
ysta
l tu
ff,
stre
am b
ed
of T
hree
hill
s C
reek
, 6
mil
es
nort
h
of
Car
bon,
A
lber
ta,
Can
ada.
R
. A
. F
olin
sbee
.
CP
R-1
20.
Dik
e fr
om
dike
zo
ne
alon
g S
outh
For
k, P
ayet
te R
iver
, w
est
of L
owm
an,
Idah
o.
B.
F.
Leo
nard
, C
. P
. R
oss.
CP
R-1
21.
Cam
as
Cre
ek
belo
w
Mye
rs
Cov
e,
Cas
to
quad
rang
le,
Idah
o.
B.
F.
Leo
nard
, C
. P
. R
oss.
P
orph
yrit
ic
biot
ite-
mus
covi
te
gra
nodio
rite
, so
mew
hat
gn
eiss
ic.
CP
R-1
22.
Nea
r Id
aho-
Mon
tana
li
ne,
Los
t H
orse
C
reek
, ne
ar
Ham
ilto
n, M
ont.
B
. F
. L
eona
rd,
C.
P.
Ros
s.
Min
eral
Zir
con_
__ _
____
__
____
_do.
___ _
_
_--_
_do_
--__
____
_____do -
----
____
.do _ _
____
_
Mon
azit
e.__
____
Mes
h si
ze
-60
+1
00
-100+
400
-20
0+
40
0
-80+
200
-400
-80+
200
-20
0+
40
0
-80
+2
00
-80+
200
a pe
r ing
pe
r hr 252
268
624
440
624
403
625
257
3,38
5
Lea
d (p
pm)
Det
erm
inat
ions
5. 8
, 6.
0
5. 5
, 6.
0
10,1
1 4.
2, 4
. 0
9. 0
, 11
9. 5
, 10
15
, 16
6. 0
, 7.
0
90,9
0
Mea
n 5.9
5.75
10.5
4.
1
10 9. 7
15
.5
6.5
90
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears 58
53 42
23
40 60
62 63
55
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Eoc
ene
or e
arly
O
ligoc
ene.
B
row
n, 1
926.
Ver
y L
ate
Cre
ta
ceou
s (u
pper
par
t of
Edm
on-
ton f
orm
atio
n).
Fol
insb
ee a
nd
othe
rs,
1957
.
Mid
dle
Ter
tiar
y.
C.
P.
Ros
s.
Ter
tiar
y (
Mio
ce
ne) .
R
oss,
19
34.
Mid
dle
Ter
tiar
y.
And
erso
n, 1
951.
Cre
tace
ous.
R
oss,
19
52.
Lat
e C
reta
ceou
s or
ea
rly
Ter
tiar
y.
Lar
sen
and
Sch
mid
t, 19
58.
00 sa
o
3
o
F
o
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 79
0
fiofi
S 4.1
.rt-
W W
IIS 0>
UO
oCOo~
»o
O <N 00
COo00
O5 CO 0=
O
CO
oCOo"
CO
0
o
o"<*'
10
CO
O 00. I I
o"
CO
ccI 1
<N UOCO <N<N O»
00
00
O OO O<N <N
3
oo00
oo o0000 00
I I I
1 Jsi _ S Ca gg T:O ^ O,Q ^t oS NS
fed ^'» « c? ^
Opn .g O +
i e§ "3 § § "?' bK*sf 2 ^ a S
Ec.t.R
t,'
|§43tk. ^
-
oT0)c oS
0) 0 C)
C c
i " O
&'£>
2 °H S a
"S c
0 T3
1?"_l
:3 t*
5 S c? cO Hi 0 t-
1S-g
<§ s+a ef"^ 0
, lls ** 05
^ «- S oS3M r » L^w>eo'g o
_O<N S q> 'S
^^.2
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
erals
Con
tinu
ed00 O
No. 65
66 67
68
Roc
k ty
pe
Fie
ld N
o.
Loc
ality
C
olle
ctor
55-im
-i.T
obac
co R
oot
bath
olit
h, n
ear
Hol
low
tow
n L
ake,
sou
thea
st
flan
k of
Mou
nt J
effe
rson
, 5
mile
s so
uthw
est
of
Pon
y,
Mon
t.
R.
R.
Rei
d.
Zir
con-
rich
"m
icro
-pla
cers
" in
da
cite
tuf
f.
55K
-307
a.
Of
Ter
tiar
y vo
lcan
ic
rock
s re
stin
g on
ero
ded
surf
ace
of
Bou
lder
ba
thol
ith,
O
beli
sk
min
e,
Jeff
erso
n C
ount
y,
Mon
t.
M.
R.
Kle
pper
. Q
uart
z m
onzo
nite
_ _
____
____
Z-2
.S
atel
liti
c st
ock
of t
he B
ould
er
bath
olit
h, M
onta
na.
R.
A.
Wee
ks.
Qua
rtz
mon
zoni
te__
_
_ __
_52
-C-1
0a.
Bou
lder
ba
thol
ith,
fr
om
the
bord
er
of
the
bath
olit
h,
7 m
iles
sout
heas
t of
H
elen
a,
Mon
t.
R.
W.
Cha
pman
.
Min
eral
__
__
_d
o
____
_do_
--_-
--_-
____
.do_
_-_-
___-
Mes
h si
ze
-80 +
400
-200 +
400
-80
+4
00
-80
+4
00
a pe
r m
g pe
r hr
493
192
336
160
Lea
d (p
pm)
Det
erm
inat
ions
13.
5
4. 2
, 4.
5
9. 0
, 10
4.6
Mea
n 4.3
5
9.5
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears 68
56 70
71
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Ear
ly T
erti
ary
or
Lat
e C
reta
ce
ous.
T
ansl
ey
and
othe
rs,
1933
.
Ter
tiar
y.
M.
R.
Kle
pper
.
Ver
y L
ate
Cre
ta
ceou
s or
ver
y ea
rly
Ter
tiar
y (p
ost-
Judi
th
Riv
er,
pre-
earl
y O
ligoc
ene)
. K
nopf
, 19
57.
Do.
o
o
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 81
O
ft O
ftO
p -s.®
s
O CO
l><Ni-H
rHcc<N
*O
06
O 0
OS OC
00
0r-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
c73
r^O_*.Is
*" dj cj ^
i"Spq PH'O
-f- -)- -j- -j-o o o o00 00 00 00
II 1 1
cS
"Xcp'Sg o os aO « rj Oo S S uM >; * S S c5
co^-
52-C-60.
Boulder batholith, roadcut miles northeast of Elk Par
Mont.
R. W. Chapman.
Alaskite
O r-lI> I>
%£SH - s
2=1+303 'r< ^l^
^Igj-SS 03 M C O *7{ «M " 55 -tJJa ° -S M £-P^ ^^1^1^
."" ^PngPHopSj^a .a
lll^lSffl P4^
0 d
icT
073
^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^ allgi! |1|ii .
alM^lal^fl lil^HgilHp!^!Z; PHr^iS^ PHf^
S g. tt
f-l -*= . -<D O ^
5-W-l.
Near margin of the Bould batholith, Boulder H Springs, Jefferson Count
Mont. R. A. Weeks.
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No. 75
76 77 78
79
Boc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
53C
-160
b.
Gra
niti
c ro
ck
incl
usio
n in
qu
artz
m
onzo
nite
of
th
e B
ould
er b
atho
lith
, M
onta
na.
R.
W.
Cha
pman
. G
rano
dior
ite
____
____
____
____
G-1
55.
Sno
qual
mie
ba
thol
ith,
al
ong
nort
h sl
ope
of G
oat
Isla
nd
Mou
ntai
n,
Mou
nt
Rai
nier
N
atio
nal
Par
k, W
ash.
D
. G
ottf
ried
, W
. L
. S
mit
h.
54-W
-48.
N
orth
si
de
of
Juli
an
Cre
ek,
nort
h c
ente
r se
c. 1
7, T
.38N
., R
.42E
., O
sgoo
d M
ount
ains
qu
adra
ngle
, O
sgoo
d M
oun
ta
ins.
Nev
. P
. E
. H
otz.
G-2
03.
Pay
mas
ter
min
e,
Cra
ters
of
th
e M
oon
Mon
umen
t, Id
aho,
D
. G
ottf
ried
, W
. L
. S
mit
h.
BC
-1-2
. S
ierr
a S
an
Ped
ro
de
Mar
tir
Mou
ntai
ns,
Baj
a C
alif
or
nia.
L
. T
. S
ilve
r.
Min
eral
___-
_do_
--_-
____
-__-
_do_
_. _
__ _
____
_do _
___
_.
Mes
h si
ze
-80
+4
00
-80+
200
-80 +
400
-80+
400
-100+
200
a pe
r mg
per h
r
340
144
378
305
3,52
9
Lea
d (p
pm)
Det
erm
inat
ions 15
3.6
10,
11
9.0
165,
170
Mea
n 10.5
168
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
110 62 69 73
99
Cite
d ge
olog
ic a
ge o
f the
ro
ck
No
dat
a.
R.
W.
Cha
pman
.
Ter
tiar
y (
post
- G
uye
form
atio
n) .
Wat
ers,
195
5.
Pre
-Mio
cene
, po
st-
Lat
e P
enns
yl-
vani
an.
P.
E.
Hot
z.
Ter
tiar
y.
Ros
s an
d F
orre
ster
, 19
47.
Ear
ly L
ate
Cre
ta
ceou
s (p
ost-
Al-
bi
an,
pre-
Mae
s-
tric
htia
n) .
Sil
ve
r an
d ot
hers
, 19
56.
00 to O § o F o
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 83
o Q
<5 O
oO
o
o s HI O
P
PH
oo
o »o
UO
el
0
CO
«5
o<Noo"
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co. C. Fri
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
era
ls C
onti
nued
00
No. 87 88
89 90
91
92
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Gra
nite
_ _
___
__
__
____
__
CF
-1.
Isth
mus
of
Teh
uant
epec
are
a,
near
H
uilo
tepe
c (O
axac
a)
IVIe
xico
. C
. F
ries
, jr
., B
. W
ebbe
r.
Gra
nite
___
____
__
____
____
_
JAL
-1.
Fou
r m
iles
sout
heas
t of
Jal
apa
(Oax
aca)
Mex
ico.
C
. F
ries
, Jr
., B
. W
ebbe
r.
Ton
alit
e__
____
__
____
__
_ _
G-1
0.
Sou
ther
n C
alif
orni
a ba
thol
ith,
A
guan
ga,
Cal
if.
E.
S. L
arse
n, J
r.
Gre
en V
alle
y to
nali
te_
____
___
G-l
l.S
outh
ern
Cal
ifor
nia
bath
olit
h,
Gre
en V
alle
y, C
alif
. E
. S.
Lar
sen,
Jr.
, D
. G
ottf
ried
. G
reen
Val
ley
tona
lite
_
____
SL
R-1
38.
Sou
ther
n C
alif
orni
a ba
thol
ith,
G
reen
Val
ley,
Cal
if.
E.
S. L
arse
n, J
r.
Tonal
ite.
___
___
__
____
__
_G
-30.
S
outh
ern
Cal
ifor
nia
bath
olit
h,
sout
hwes
t of
Pal
m S
prin
gs,
Cal
if.
E.
S. L
arse
n, J
r.,
D.
Got
tfri
ed.
Min
eral
__
__
.do
-__
__
__
_
_.__
_do __ _
____
___-
_do_
--_-
__
-_._
_do_
-_-_
____
-_._
_do _
_-_
-_.
Mes
h siz
e
-80
+2
00
-80
+2
00
-100+
200
-100 +
200
-100 +
200
-10
0 +
200
a pe
r m
g pe
r hr 310
104
280
149
340
317
Lea
d (p
pm)
Det
erm
inat
ions 12
4. 0
, 5.
0
11 6.0
15
14
Mea
n 4.5
Lead
- al
pha
age
in
mill
ions
of
yea
rs 96 108 98 100
110
110
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pos
t-pr
obab
le P
ale
oz
oic.
B
. W
eb
ber,
C.
Fri
es,
Jr.
Do.
Ear
ly
Lat
e C
re
tace
ous
(pos
t-
Lat
e T
rias
sic,
pr
e-L
ate
Cre
ta
ceou
s) .
Lar
- se
n, 1
948.
D
o.
Do.
Do.
§ o F
O
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 85
o O
o O
oP
o Q
o O
Cec
i£cc
C
oc ocC
l> C1-1 crcs
O8+o o
+200 00+200 +2 00+20U 00+2 00 + 200 00+200
00 OJ
506320 5S
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
101
102
103
104
105
106
Roc
k ty
pe
i ie
ld N
o.
Loc
ality
C
olle
ctor
Mou
nt H
ole
gran
odio
rite
- ___
_Z
-17.
S
outh
ern
Cal
ifor
nia
bath
olit
h,
Mou
nt H
ole,
Cal
if.
E.
S. L
arse
n, J
r.
Sto
new
all
gran
odio
rite
_ _
____
G-4
8.
Sou
ther
n C
alif
orni
a ba
thol
ith,
S
tone
wal
l M
ount
ain,
Cal
if.
E.
S. L
arse
n, J
r.
Woo
dson
Mou
ntai
n gr
anod
iori
te
S-6
. S
outh
ern
Cal
ifor
nia
bath
olit
h,
nort
heas
t of
Des
cans
o Ju
nc
tion
, C
alif
. E
. S.
Lar
sen,
Jr.
W
oods
on M
ount
ain
gran
odio
ri
te.
Z-1
6.
Sou
ther
n C
alif
orni
a ba
thol
ith,
D
esca
nso
Junc
tion
, C
alif
. E
. S.
Lar
sen,
Jr.
W
oods
on M
ount
ain
gran
odio
ri
te.
G-3
2A.
Sou
ther
n C
alif
orni
a ba
thol
ith,
w
est
of E
lsin
ore,
Cal
if.
E.
S. L
arse
n, J
r.
Woo
dson
Mou
ntai
n gr
anod
io
rite
. S
-2.
Min
eral
Zir
con.
___
____
_
____
_do_
_-_-
--_-
____
_do _
_-.
-_-
Zir
con.
___
____
_
Xen
otim
e___
__.
____
_do ..
......
Mes
h siz
e
-100+
200
-10
0+
20
0
-100+
200
-100+
200
-100+
200
-100+
200
-100+
200
-100+
200
aper
mg
per
hr
1,2
04
545
1,18
0
6,43
0
1,23
5
6,40
0
457
433
Lea
d (p
pm)
Det
erm
inat
ions 46 21 46
360 50
260 22
20,2
2
Mea
n 21
Lead
- al
pha
age
in
mill
ions
of
yea
rs 95 96 97
117
10^
104
120
12.7
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Ear
ly L
ate
Cre
ta
ceou
s (p
ost-
L
ate
Tri
assi
c,
pre-
Lat
e C
re
tace
ous)
. L
ar
sen,
194
8.
Do.
Do.
Do.
Do.
Do.
Do.
00
O5
Sou
ther
n C
alif
orni
a ba
thol
ith,
1
mile
sou
th
of
Tem
ecul
a,
Cal
if.
E.
S.
Lar
son,
Jr.
107
Gra
nit
e_
____________.
Z-1
5.S
outh
ern
Cal
ifor
nia
bath
olit
h,
Rub
idou
x M
ount
ain,
C
alif
. E
. S.
Lar
sen,
Jr.
108
Gra
nit
e___________.
EL
-167
.S
outh
ern
Cah
'forn
ia b
atho
lith
, R
ubid
oux
Mou
ntai
n, C
alif
. E
. S.
Lar
sen,
Jr.
109
Rat
tles
nake
gra
nit
e___._
___..
X-1
01.
Sou
ther
n C
alif
orni
a ba
thol
ith,
C
uyum
aca
quad
rang
le, C
ali
fo
rnia
. E
. S.
Lar
sen,
Jr.
110
Gra
nodi
orit
e_ _
____
____
____
__R
CE
-54-
7-28
A.
Pom
ona
Til
e qu
arry
, M
ojav
eD
eser
t ar
ea,
Cal
ifor
nia.
R
. C
. E
llis
.11
1 G
rani
te__
____
____
____
_ .
RC
E-5
4-7
-14
B.
Nee
iiac
h qu
adra
ngle
, M
ojav
eD
eser
t ar
ea,
Cal
ifor
nia.
R
. C
. E
llis
.11
2 Q
uart
z m
onzo
nit
e______-_
_.
G-2
1.S
outh
ern
Cal
ifor
nia
bath
olit
h,
Pro
vide
nce
Mou
ntai
n, C
alif
. E
. S.
Lar
sen,
Jr.
113
Qua
rtz
monzo
nit
e_._
______.
G-2
4M.
Sou
ther
n C
alif
orni
a ba
thol
ith,
Sod
a L
ake,
Cal
if.
E.
S. L
arse
n, J
r.
Zir
con
(met
a-
mic
t).
Zir
con.
Xen
otim
e.
Zir
con.
.do.
.do.
Zir
con
(met
a-
mic
t).
-100+
200
-100+
200
-100+
200
-80 +
200
-80+
200
-100 +
200
-100+
200
2,70
0
725
1,74
3
237
866
610
4,6
60
106 29 80
& 0
, 9.
0
30,3
2 23 180
8.5
31
98 99 117 89 89 94 96
Do.
Do.
Ear
ly L
ate
Cre
ta
ceou
s (p
ost-
L
ate
Tri
assi
c,
pre-
Lat
e C
re
tace
ous)
. E
ver
- h
art,
195
1.M
esoz
oic.
M
ille
r,
1946
.
Do.
Do.
Do.
00
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
114
115
116
117
118
119
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Qua
rtz
mon
zoni
te _
___
____
__R
CE
-54-
7-14
C.
Ros
amon
d qu
adra
ngle
, M
o-
jave
Des
ert
area
, C
alif
orni
a.
R.
C. E
llis
.
RC
E-5
4-7-
18A
. Iv
anpah
qu
adra
ngle
, M
ojav
e D
eser
t ar
ea,
Cal
ifor
nia.
R
. C
. E
llis
.
RC
E-5
4-7-
27C
. W
hite
tan
ks,
sout
h of
Tw
enty
N
ine
Pal
ms,
Moj
ave
Des
ert
area
, C
alif
orni
a.
R.
C.
Ell
is.
Gra
nite
_ _
___
____
__ _
RC
E-5
4-7-
28B
. G
rani
te M
ount
ains
, so
uthe
ast
of
App
le
Val
ley,
M
ojav
e D
eser
t ar
ea,
Cal
ifor
nia.
R
. C
. E
llis
. 8uar
tz m
onzo
nite
___
____
____
_-2
8.
Sou
ther
n C
alif
orni
a ba
thol
ith,
B
erdo
o C
anyo
n, C
alif
. E
. S.
Lar
sen,
Jr.
G-1
5.S
outh
ern
Cal
ifor
nia
bath
olit
h,
Cot
tonw
ood
Spr
ings
, C
alif
. E
. S.
Lar
sen,
Jr.
Min
eral
Zir
con.
___
_ __
_
__--
_do_
-___
_-_-
__--
_do___--
-_-
_-_
-_d
o_
--~
.-_-
-_._
_do.-
--_--
__
__
_._
do
_--
~-_
_
Mes
h si
ze
-80
+2
00
-80
+2
00
-80
+2
00
-80
+2
00
-100+
200
-100+
200
a pe
r m
g pe
rhr
203
171
267
590
385
190
Lea
d (p
pm)
Det
erm
inat
ions
8. 0
, 8.
0
& 0
, 7.
0
12,1
3
27,
281
20
10
Mea
n 8.0
7. 5
12.5
27.
5
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears 98
109
116
116
129
131
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Mes
ozoi
c. M
ille
r,
1946
.
Do.
Do.
Do.
Do.
Do.
00
00 o § F
O
O
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 89
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 97
*ho S fr o a A-S o ot5s~ sa>_^»ci >H I'S rf
o P
oft
c5p
op A.
"5
c> CJ
(Nr-(
cT
COeo
(0 t~oo
sI
Oo<N
o00
-a
1 OQ
era!.'
03S*S «
-S^S^MS^SI^UI^
KM WP* Opq QOOo
6.
Halford, Sultan quad-
gle, Washington.
oried, W. L. Smith.
g «g'Bb . * S ^|l i13 £w 0* .4
t|l .£ a « «2r% O-f
1°|3 ^il^ IllllS«N g'43 2"o:§?»
'HOO P
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Conti
nued
No.
IRQ
.toy
170
171
172
173
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
To
nal
ite.
.. _
________
HC
-2.
Che
lan
bat
ho
lith
, L
ower
Kna
pp
Cou
lee
(eas
t si
de),
Che
lan
quad
rang
le,
Was
hin
gton
.C
. A
. H
opso
n.G
neis
sic
ho
rnb
len
de-
qu
artz
dior
ite.
FW
-60-
55.
Che
lan
bath
olit
h,
Hol
den
quad
rang
le,
nort
h si
deE
ntia
t R
iver
, 3
mile
s so
uth
of H
olde
n, W
ash.
F.
W.
Cat
er.
Gra
nodi
orite
____
.
DF
C-1
06-
55.
Hol
den
quad
rang
le,
Was
hing
to
n.D
. F
. C
row
der.
Ton
alit
e. _
____
___ _
HC
-1.
Che
lan
bat
holi
th,
Upper
K
napp
C
oule
e (w
est
side
),C
hela
n qu
adra
ngle
, W
ash
ingt
on.
C.
A.
Hop
son.
Ton
alit
e.__
___ _ _
_ _
DF
C-1
07-5
5.H
olde
n qu
adra
ngle
, W
ash
ingt
on.
D.
F.
Cro
wde
r.
Min
eral
Zir
con _
. ___
. .d
o.........
. _ .d
o _____
_. ..
.do... .
....
.
. _ .d
o..
....
_
Mes
h si
ze
-80+
200
-80+
200
-80
+2
00
-80+
200
-80
+2
00
aper
mg
per h
r no
yo 78 110 83 56
Lea
d (p
pm)
Det
erm
inat
ions
4. 0
, 4. 2
3. 2
, 3. 5
5. 4
, 4. 4
40
41
^C*
Vf
^C*
-L
2. 5
, 3. 2
Mea
n 41 X
3.35
4.9
4.05
2.85
Lea
d,
alph
a ag
e in
m
illio
ns
of y
ears 104
107
in 121
126
Cite
d ge
olog
ic a
ge o
f the
ro
ok
Pre
-Pal
eoce
ne,
post
-ear
lyM
esoz
oic.
Wat
ers,
193
8.
Do.
Do.
Do.
Do.
CO
0
0 1
174
175
176
177
178
179
Qua
rtz
dior
ite_
____
____
____
FC
-1.
Hol
den
quad
rang
le,
Was
hing
to
n.F.
W.
Cat
er.
Gra
nodi
orite
_ __
____
____
____
_G
-122
.Si
milk
amee
n ba
thol
ith,
2 m
iles
from
B
icht
er
Ran
ch,
near
W
ashi
ngto
n-B
riti
sh C
olum
bi
a bo
rder
, B
riti
sh C
olum
bi
a, C
anad
a.D
. G
ottf
ried
, W
. L
. S
mit
h.G
rano
dior
ite_
____
____
____
___
RE
F-1
.N
elso
n ba
thol
ith,
Low
er A
rrow
L
ake
dist
rict
, B
riti
sh
Co
lu
mbi
a, C
anad
a.R
. A
. Fo
Lins
bee.
Leu
cosy
enit
e. _
____
____
____
__38
81.
Nea
r M
ount
F
airp
lay,
m
ile-
post
29,
For
tym
ile
dist
rict
, ea
st-c
entr
al A
lask
a.A
. N
elso
n, J
. J.
Mat
zko.
Gra
nodi
orit
e___
____
____
____
54-A
Pr-
106.
Tak
u In
let,
near
ou
tlet
of
Tur
ner
Lak
e, w
est o
f Jun
eau,
sout
heas
tern
Ala
ska.
G
. P
lafk
er.
Dio
rite
__._
____
____
____
____
_55
-ASn
-242
.T
olst
oi P
oint
, P
rinc
e of
Wal
es
Isla
nd
, n
ort
hea
st-c
entr
al
part
of
C
raig
qu
adra
ngle
, so
uthe
aste
rn A
lask
a.C
. S.
Sai
nsbu
ry.
.do.
.do.
.do.
.do.
Zir
con
(met
amic
t).
Zir
con.
.do.
-100+
200
-80
+2
00
-100+
200
-60
+2
00
-200+
400
-100
74 160
310
1,270
1, 134
1,47
61,550
1,62
01,
930
1,594
2,600
152
142
4.0
7. 2
, 7.
5
13,1
4
48,52 45 63
60,63 68 72 72 115
5. 8
, 5.
6
5. 8
, 6. 0
7.35
13.5
50 61. 5
5.7
5.9
134
114
108 98 99 100 99 104 93 11£?
110 93 103
Do.
Do.
Lat
e C
reta
ceou
s or
yo
unge
r.
Sm
ith
and
Ste
vens
on,
1955
.
Mes
ozoi
c.
Mer
tie,
19
37.
Lat
e E
arly
C
reta
ce
ous
or L
ate
Ju
rass
ic (?
). B
ud-
ding
ton
and
Cha
- pi
n, 1
929.
Do.
1 § on CO
C
O
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
180
181
182
183
184
185
186
Boc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
13-A
. P
orcu
pine
C
reek
, K
usku
lana
R
iver
are
a,
Chi
tina
Val
ley,
ea
st-c
entr
al A
lask
a.
J. F
. S
eitz
. G
rani
te p
orp
hyry
...-
.---
----
SC
C-1
. N
ear
San
Man
uel,
Ari
z.
S. C
. C
reas
ey.
Peg
mat
itic
fac
ies
of n
ephe
line
sy
enit
e.
56-2
. L
arvi
kofj
orde
n, N
orw
ay.
T.
F.
W.
Ear
th.
Peg
mat
itic
nep
heli
ne s
yen
ite.
. 56
-3.
Tve
itda
len,
Nor
way
. T
. F
. W
. E
arth
.
TB
-7.
Bar
kevi
k,
Lan
gesu
ndsf
jord
, so
uthe
rn N
orw
ay.
T.
F.
W.
Ear
th.
56-8
. L
aven
Lan
gesu
ndsf
jord
, so
uth
er
n N
orw
ay.
T.
F.
W.
Ear
th.
Cat
acla
stic
met
anor
ite _ .
N-l
. D
jupd
alen
, L
osby
, L
oren
skog
H
erad
, A
kers
hus,
so
uthe
rn
Nor
way
. H
. F
aul,
0.
Hol
teda
hl.
Min
eral
Zir
con.
... ..
.
__
_ d
o __
___
....
.do..
. ___ .
....
.do..
. ___
....
.do..
. ___ .
....
.do..
. ___
Mes
h siz
e
-80+
400
-80+
400
+ 2
0
+20
+20
+ 2
0
-100+
200
aper
mg
per h
r
283 73 177 76
75 324
108
Lead
(pp
m)
Det
erm
inat
ions
11,1
3
3. 0
, 3.
5, 4
. 0
9.0
,11
4. 9
, 4.
9
5. 0
, 5. 0
, 5.
0,
5.0
20,2
5
7. 0
, 8. 0
, 9. 0
Mea
n
12 3.5
10 4.9
5.0
22.5
8.0
Lead
- al
pha
age
in
mill
ions
of
yea
rs
105
115
140
160
160
173
184
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Lat
e E
arly
C
reta
ce
ous
or L
ate
Ju
rass
ic (?
).
Bud
- di
ngto
n an
d C
ho
pin,
192
9.
Lat
e C
reta
ceou
s or
ea
rly
Ter
tiary
. S.
C.
Cre
asey
.
Ear
ly P
erm
ian.
H
oegh
, 19
36.
Do.
Do.
Do.
No
data
. H
. Fa
ul.
o
o
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 101
9'£'S O*fita) j3 PH W> 0>>8 fl1«
W
^» ®
I*8' & P
Carboniferous (?) (pre-Santa
Rosa forma tion). C.
Fries, Jr.
si **I10|gj
H
Pre-Permian.
Bramkamp an<
others, 1956.
$
usCO 00
o00
CO
CJ
USOCO
COo»CO 00
eo"
c G
-d"
o PI a
ik, Langesundsf;
s^ay. r . Earth,
ine s venite- .--.
c c
-sSO
**?18If « rfi
' -cT . ^< ^^
0 d
o ®'s 1
;, Bedil, 2nd Divi i Sarawak, British
3 in Borneo.
Eloe.
c-c
+» CQ
8-S>S ES o
u, 2nd Division, ivak, British Terrii
>rneo. Roe.
CT:
S3'a* &3s X>
1 ^ ,O psj _-2
ol tl e M o* 1^ 5
i"S
§1 .ga
^ bD
*«> 05 _J ^ 42ls-i 1 4 §11 ; l
"C * * o31 Is! i 51~ 'S -ja «SAt J-:§|^^w.
§^1^^121^.' 5 Wtf^^O
506S20 59 6
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
194
195
196
197
198
199
200
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Coa
rse
gray
por
phyr
itic
gra
n
ite.
S
A-2
. E
aste
rn s
ide
of e
aste
rn b
atho
- li
th,
Sau
dia
Ara
bia.
G
. F
. B
row
n.
Gra
nite
roc
k___
____
____
____
_S
A-3
. Je
bal
Z'a
ba,
Sau
di A
rabi
a.
G.
F.
Bro
wn.
F
ine-
grai
ned
gray
gr
anod
io-
rite
. S
A-4
. T
aif ,
Sau
di A
rabi
a.
G.
F.
Bro
wn.
Sa-
6.
Dha
lm,
Sau
di A
rabi
a.
G.
F.
Bro
wn.
S-4
6.
Ash
away
qu
adra
ngle
, R
hode
Is
land
. W
. L
. S
mit
h.
Nar
rag
anse
tt P
ier
gran
ite
____
_Q
-55-
3.A
shaw
ay
quad
rang
le,
Rho
de
Isla
nd.
A.
W.
Qui
nn.
Wes
terl
y gr
anit
e___
_
Q-5
5-4.
A
shaw
ay
quad
rang
le,
Rho
de
Isla
nd.
A.
W.
Qui
nn.
Min
eral
Zir
con_
.___
____
* -
ClO
do
-
Mon
azit
e _ _
___
Mes
h si
ze
-60
+2
00
-60
+2
00
-60
+4
00
-60
+4
00
-80
+2
00
-80+
200
-80
+2
00
otpe
rmg
per
hr 460
360
483
2,08
3 1,
970
380
410
462
304
300
5,49
4
Lea
d (p
pm)
Det
erm
inat
ions
65,
68,
47, 4
9,
61
302,
305
, 30
7, 3
08
48,
50,
50
62,6
5 62
,65
27,2
9
25,2
6
580,
590
Mea
n
66
.5
48 303
307 49 63.5
6
3.5
28
25.5
585
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
340
323
300
35J
377
314
373
333
225
208
220
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pre
-Per
mia
n.
Bra
mka
mp
and
ot
hers
, 19
56.
Do.
Do.
Do.
Lat
e or
pos
t-
Pen
nsyl
vani
an.
Qui
nn a
nd
othe
rs,
1957
.
Do.
Do.
M
OB a o s o
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 103
oft oft o
flo-
. go §-<
£
fl
O fi
% fr- (N
sooo
ooooIN**
o oo ooo oooo o oo
oo<N
o oo ooo
a o o&
<%
~ s sa-SISH {23
*rt <pa £g|&I<H
& 11 50
O "
oT o
i 12 * oo.J
O S «Q af 1-1S o3 a>i°lw «w S0 oW o1
.1o .^j(P Tj< £H
^z»0^ f||l^ P i^i^isl^ P iil^llilll^
O"
3
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
208
209
210
211
212
213
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Q-5
3-39
. T
ower
H
ill
Roa
d,
2,50
0 fe
et
sout
h of
M
oore
sfie
ld
road
, N
arra
gans
ett
Pie
r qu
ad
rang
le,
Rho
de I
slan
d.
A.
W.
Qui
nn.
Sci
tuat
e gr
anit
e gn
eiss
___ _
__Q
-53-
37.
Geo
rgia
vill
e qu
adra
ngle
, F
or-
num
Pik
e, 1
,200
fee
t so
uth
ea
st o
f w
est
end
of C
apro
n ro
ad,
Rho
de I
slan
d.
A.
W.
Qui
nn.
One
co g
ran
ite.
... _
____
__53
-S-4
8.
Moo
sup,
Con
n.
W.
L.
Sm
ith.
S
yen
ite.
- ___
____
__
_ _
____
_V
t-S
y-5
6J-
12
. W
hite
Mou
ntai
n pl
uton
ic-v
ol-
cani
c se
ries
, ne
ar s
umm
it o
f M
ount
Asc
utne
y, V
t. H
. W
. Ja
ffe,
J.
B.
Lyo
ns.
Gra
nite
_ _ _ _
____
_ _
____
_V
t-G
r-56J-
13.
Whi
te M
ount
ain
plut
onic
-vol
- ca
nic
seri
es,
belo
w s
umm
it
of M
ount
Asc
utne
y, V
t.
H.
W.
Jaff
e, J
. B
. L
yons
.
NH
-M-5
6J-
17
.
Min
eral
__-_
.do_
____
____
____
_ do
... .
....
_
__._
_do_
__ ...
...
....
.do
. __ ..
..
..._
.do
_. _
....
Mes
h si
ze
-80
+2
00
-80+
200
-80
+2
00
-80+
200
-200+
400
-80
+2
00
-2
00+
400
-80+
200
aper
mg
per h
r
800
352
251
544
166
214
247
373
240
260
Lea
d (p
pm)
Det
erm
inat
ions
100 44
35
63,6
5
11,1
2 17
,20
19,2
2 25
,27
16,1
7 18
,20
Mea
n
64 11.5
18
.5
20.5
26 16
.5
19
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
305
303
337
286
170
211
210
175
171
IBS
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Dev
onia
n.
Qui
nn
and
othe
rs,
1957
.
Do.
No
dat
a.
Mis
siss
ippia
n (?
) .
Bil
ling
s,
1956
. L
ate
Per
mia
n (?
).
Lyo
ns a
nd o
ther
s,
1957
.
Do.
Do.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 105
o ft
ofl
oft
CO O*Q C50*0 * coCNINNIN
>oco coco
IOco co
oocot>- us«o IOCD1O<oooooi
OINCO
CO CO CO
00O3(N
co oo"*O
o«oot>-
oo o oo
o o
oo oo o oCO
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
erals
Con
tinu
ed
No.
218
219
220
221
222
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Mou
nt O
sceo
la g
rani
te _
____
__33
-BN
H-1
7.W
hite
Mou
ntai
n pl
uton
ic-v
ol-
cani
c se
ries
, M
ount
Cho
cura
qu
adra
ngle
, N
ew
Ham
p
shir
e.
A.
But
ler.
F
ayal
ite
quar
tz s
yen
ite,
___
___
BN
H-2
0.
Dev
ils
Slid
e ri
ng d
ike,
W
hite
M
ount
ain
plut
onic
-vol
cani
c se
ries
, P
ercy
qu
adra
ngle
, N
ew H
amps
hire
. A
. B
utle
r.
MR
-1.
Sto
ck,
Mon
tere
gian
H
ills
, M
ount
R
oyal
, M
ontr
eal,
Q
uebe
c, C
anad
a.
J. B
. L
yons
. W
inne
pesa
ukee
qua
rtz
dior
ite__
N
H-W
Qd
-56
J-16.
New
Ham
pshi
re p
luto
nic
seri
es,
sout
h of
B
elkn
ap
Poi
nt,
Lak
e W
inne
pesa
ukee
qua
d
rang
le,
New
Ham
pshi
re.
H.
W.
Jaff
e, J
. B
. L
yons
. K
insm
an q
uart
z m
onzo
nite
___
NH
-LM
-1-5
2.
Min
eral
Zir
con.
___
____
_
Zir
con
Th
:U=
2.1
c=
2,3
85.
Che
vkin
ite
Th
:U=
54
c=
2,0
50
fc=
0.50
X!0
-*
Zir
con
(met
amic
t) .
Zir
con_
____
____
Zir
con
Th:U
=0.4
Mes
h si
ze
-60+
200
-60 +
200
-10
0+
20
0
-80 +
200
-80
+2
00
-2
00+
400
-10
0+
20
0
aper
mg
per
hr 470
723
843
465
443
995
2,32
3
353
391
248
Lea
d (p
pm)
Det
erm
inat
ions 50
68
80 44 42 98
210,
215
38,4
0 45
,47
26,3
0
Mea
n
213 39
46 28
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
259
230
232
220
224
20.
224
269
285
28#
Oite
d ge
olog
ic a
ge o
f the
ro
ck
Mis
siss
ippi
an(?
).
Bil
ling
s, 1
956.
L
ate
Per
mia
n (?
).
Lyo
ns a
nd
othe
rs,
1957
.
Do.
Lat
e P
aleo
zoic
. L
yons
and
oth
ers
1957
.
Lat
e D
evon
ian
(?)
(pos
t-E
arly
D
evon
ian)
. B
illi
ngs,
195
6.
Lyo
ns a
nd
othe
rs,
1957
.
Do.
O
O-
223
224
225
226
New
Ham
phir
e pl
uton
icse
ries
, L
ovew
ell
Mou
ntai
n qu
ad
rang
le,
New
Ham
pshi
re.
J. B
. L
yons
.
Kin
sman
qua
rts
mon
zoni
te _
NH
-C
2-52
. N
ew H
am
pshi
re p
luto
nic
seri
es,
Car
diga
n qu
adra
ngle
, N
ew
Ham
pshi
re.
J. B
. L
yons
. B
ethl
ehem
gne
iss _
____
____
___
NH
-K-8
-52
-1.
New
Ham
pshi
re p
luto
nic
seri
es,
Rum
ney
quad
rang
le,
New
H
amps
hire
. J.
B.
Lyo
ns.
NH
-S-4
-52-1
. N
ew H
amps
hire
plu
toni
c se
ries
, S
unap
ee
quad
rang
le,
New
H
amps
hire
.J.
B.
Lyo
ns.
Con
cord
gra
nit
e.
____
____
___
NH
-Big
-56-J
-20.
Bin
ary
gran
ite,
N
ew
Ham
p
shir
e pl
uton
ic s
erie
s, S
wen
son
quar
ry,
Con
cord
, N
.H.
H.
W.
Jafl
fe,
J. B
. L
yons
.
c= 2
,560
k
=1
.74
X1
0-*
Mon
azit
e T
h:U
=33
c= 2
,065
fc
=0.
61X
10-*
__._
_do_
___-
__
Zir
con
Th
:U=
1.4
c=
2,4
55
fc =
1.47
X10
-*
Mon
azit
eT
h:U
=8.5
c=
2,1
80
fc
=0.
87X
10~*
X
enot
ime
Th:U
=54
c= 2
,048
fc
=0.
56X
10~*
. M
onaz
ite _
___
_
100+
200
-100+
200
-10
0+
20
0
-100 +
200
-100 +
200
-100+
200
-80
+2
00
4,35
1
333
246
94
9
2,92
2
4,05
3
5,35
2
640,
800
36,3
8 28 ^n 470
530
825,
835
720 07
830
337
270
277
297
Do.
Do.
Do.
266
320
Do.
fe S § GO
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Conti
nued
No.
227
228
229
230
231
Boc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Con
cord
gra
nite
. ___
.
NH
-C-4
-52-
1.
Bin
ary
gran
ite,
N
ew H
amp
sh
ire
plut
onic
ser
ies,
Car
di
gan
quad
rang
le, N
ew H
amp
sh
ire.
J.
B.
Lyo
ns.
Peg
mat
ite
in C
onco
rd g
rani
te
NH
-C-5
-52-
E.
New
Ham
pshi
re p
luto
nic
serie
s,
Car
diga
n qu
adra
ngle
, N
ew
Ham
pshi
re.
J. B
. L
yons
.
NH
-Gr-
56-J
-19.
In
Fit
chbu
rg p
luto
n on
U.S
. H
ighw
ay 3
, 4.
2 m
iles
sout
h of
Sun
cook
Riv
er,
Mar
tin,
Su
ncoo
k qu
adra
ngle
, N
ew
Ham
pshi
re.
H.
W.
Jaff
e, J
. B
. L
yons
.
NH
-di-
56-J
-18.
E
xete
r pl
uton
, be
twee
n E
xete
r an
d E
ppin
gj N
.H.
H.
W.
Jaff
e, J
. B
. L
yons
. M
etar
hyol
ite_ __ __
NH
-L-1
-56.
Lit
tlet
on f
orm
atio
n, L
ittl
eton
, N
.H.
J. B
. L
yons
.
Min
eral
Mon
azit
e T
h:U
=4
6
c= 2
,052
fc
=0.
58X
10-*
.
Zir
con
____
____
__
_ d
o ___
__
_
____
_do_
____
_
Mes
h si
ze
-100+
200
-100+
200
-80
+2
00
-80+
200
-80+
200
a pe
r in
g pe
rhr
2,7
84
5,28
5
394 75
53
Lea
d (p
pm)
Det
erm
inat
ions
450
700
45,4
8
9. 0
, 10
6. 0
, 7. 0
Mea
n
46
.5 9.5
6.5
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
320
274
286
307
295
Cite
d ge
olog
ic ag
e of t
he
rock
Lat
e D
evon
ian(
?)
(pos
t-E
arly
D
e
voni
an).
Bill
ings
, 19
56.
Lyo
ns a
nd
othe
rs,
1957
.
Do*
Do.
Do.
Ear
ly t
o M
iddl
e D
evon
ian
(Ori
s-
kany
-Ono
ndag
a ag
e).
J. B
. L
yons
.
o
oo o 1
232
233
234
235
236
237
238
Fels
ic v
olca
nics
,___
____
____
__N
H-M
o-3-
56.
Hig
h gr
ade
zone
of
Lit
tlet
on
form
atio
n,
east
of
L
isbo
n,
N.H
.J.
B.
Lyo
ns.
Gra
nit
e_______._
______..
..N
H-M
W-4
-52-
1.O
liver
ian
plu
tonic
se
ries
, M
ount
W
ashi
ngto
n qu
ad
rang
le,
New
Ham
pshi
re.
J. B
. L
yons
.L
eban
on g
rani
te,
bord
er g
neis
s.N
H-H
-6-5
2-1.
Oli
ver
ian
plu
ton
ic
seri
es,
Mou
nt
Was
hing
ton
quad
ra
ngle
, N
ew H
amps
hire
.J.
B.
Lyo
ns.
Leb
anon
gra
nite
_'__
___
NH
-H-1
-52.
Han
over
qu
adra
ngle
, N
ew
Ham
pshi
re.
J. B
. L
yons
.A
plite
in
Leb
anon
gra
nit
e...
..N
H-H
-2-5
2-1.
Oli
ver
ian
plu
ton
ic
seri
es,
Han
over
qu
adra
ngle
, N
ew
Ham
pshi
re.
J. B
. L
yons
.G
rani
te o
f M
asco
ma
gro
up
..
NH
-H-5
0-52
.O
liv
eria
n
plu
tonic
se
ries
, M
asco
ma
quad
rang
le,
New
H
amps
hire
.J.
B.
Lyo
ns.
Pin
k gran
ite .
Me-
Gr-
56J-
21.
Bid
defo
rd
gran
ite,
K
enne
- bu
nk q
uadr
angl
e,
Wel
ls,
Mai
ne.
J. B
. L
yons
, H
. W
. Ja
ffe.
.do.
Zir
con
Th:
U=
2.3
c=2,
390
fc 1
.31X
10-*
Zir
con
Th
:U=
l.l
c=2,
475
fc=
l. 5
5X10
-*
Zir
con
Th:
U=
0.56
c=
2,54
0 fc
=1.
69X
10-*
Zir
con
Th:U
=0
c=2,
632
fc=
1.90
X10
-*
Zir
con
Th:
U=
1.3
c=2,
460
k=
1.50
X10
-*
Zir
con.
80+
400
100
+20
0
-100+
200
-100+
200
100
+20
0
100
+20
0
-80+
200
-200
+40
0
165
498
217
574
980
514
348
410
21,2
2 61 27 79 130
60
,63
42,4
547
,48
21.5
61.5
43.5
47.5
287
BQ1
340
337
28S
305
Do.
Mid
dle
to L
ate
Dev
onia
n (?
). B
illin
gs,
1956
, L
yons
and
ot
hers
, 19
57.
Do.
Do.
Do.
Do.
Mid
dle
to L
ate
De
vo
nian
. L
yons
an
d ot
hers
, 19
57.
O
CO
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f ac
cess
ory
min
era
ls C
onti
nued
No.
239
240
241
242
243
244
Roc
k ty
pe
Fiel
d N
o,
Loc
ality
C
olle
ctor
Gra
nite
_ _
___ _
_ _
____
____
_A
B-1
. N
ear
Par
lin
Pon
d,
Jack
man
, M
aine
. A
. J.
Bou
cot.
JBL
-Me.
N
ear
Par
lin
Pon
d,
5 m
iles
so
uth
of J
ackm
an,
Mai
ne.
J. B
. L
yons
.
AB
-2.
Kat
ahdi
n ba
thol
ith,
ne
ar
Ri-
po
genu
s da
m,
Mai
ne.
A.
J. B
ouco
t. K
ineo
rhy
olit
e, i
ntru
sive
pha
se.
AB
-3.
Nor
thea
st
par
t of
B
rass
ua
quad
rang
le,
Som
erse
t C
oun
ty
, M
aine
. A
. J.
Bou
cot.
AB
-5.
Big
Dum
p qu
arry
, S
t. G
eorg
e,
New
Bru
nsw
ick,
Can
ada.
A
. J.
Bou
cot.
Gra
y gr
anit
e___
____
___-
_-__
_A
B-6
. S
outh
east
ti
p
of
Poc
olog
an
Har
bor,
C
harl
otte
C
ount
y,
New
B
runs
wic
k,
Can
ada.
A
. J.
Bou
cot.
Min
eral
Zir
con_
_ __
____
_
____
_do_
- ...
_ __
do --
---
___-
do-_
__ _
_
_____do____. _
___ d
o _
__
__
Mes
h si
ze
-80+
200
-80+
200
-80+
200
-20
0+
40
0
-200+
400
-80+
400
-80
+2
00
-2
00+
400
-400
aper
mg
pe
rhr
315
248
237
212
230 95 363
164
229
232
Lea
d (p
pm)
Det
erm
inat
ions 43
33,3
3 30
,29 28
30 11
45,4
5
24
,26
34
,33
34,3
6
Mea
n
33
29
.5
45 25
33.5
35
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
330
320
300
320
310
281
30-
BQ8
354
364
Cite
d ge
olog
ic ag
e of
the
rock
Mid
dle
Dev
onia
n.
A.
J. B
ouco
t.
Do.
Pos
t-E
arly
D
evo
ni
an.
Bou
cot.
1954
.
Lat
e E
arly
D
evo
ni
an.
A.
J.
Bou
cot.
Mid
dle
Dev
onia
n (p
ost-
Eas
tpor
t,
pre-
Per
ry f
orm
a
tion
).
A.
J.
Bou
cot.
Pre
- Mid
dle
Sil
uria
n (?
).
A.
J. B
ouco
t.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 111
.fS-gS orfS-1
Sil
M
I
O P
O
pOp
*§ .'E S
> §§ §8,30|>£
SflsHi
Op
Op
co
»0 <N
OCO
o o
o o
o o
+ +o o<N
fl'
8(£'Cs!
.2 ®
itT1 *3
»Ho'Q *S "S9 3 O rr< §1
-fi g-3'S. ftoS
aS* w ?|?J I? 3 "
fj,;j|figPg|!|fj{f|l. * tS y O ^* » » O ^ O H«4 ^ i 2 -» ^* y-i0"-5^sSa3 |l2! ^SK I3^ 33gA3Sflrigiia!Sri^ftaia«
OiziW H^^iziW H^fcW H^G?
CO
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinue
d
No.
252
253
254
255
256
257
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Sw
arth
mor
e gr
anod
iori
te
AW
P-1
.N
ear
Spri
ngfi
eld,
Phi
lade
lphi
a ar
ea,
Pen
nsyl
vani
a.
A.
W.
Post
el.
AW
P-8
. N
ear
Falls
Bri
dge,
Fai
rmou
nt
Par
k,
Phi
lade
lphi
a ar
ea,
Pen
nsyl
vani
a.
A.
W.
Pos
tel.
Sw
arth
mor
e gr
anod
iori
te.
S-23
. N
ear
Spri
ngfi
eld,
Phi
lade
lphi
a ar
ea,
Pen
nsyl
vani
a.
A.
W.
Post
el.
Apl
itic
phas
e,
Sw
arth
mor
e gr
anod
iori
te.
S-1
6.
Nea
r Sp
ring
fiel
d, P
hila
delp
hia
area
, P
enns
ylva
nia.
A
. W
. Po
stel
. S
war
thm
ore
gran
odio
rite
__
AW
P-5
. In
term
edia
te
repl
acem
ent
type
, E
ast
Lak
e P
ark,
Phi
l
adel
phia
are
a, P
enns
ylva
nia.
A
. W
. Po
stel
. S
war
thm
ore
gran
odio
rite
.
AW
P-6
. In
term
edia
te
repl
acem
ent
type
, C
lifto
n H
eigh
ts,
Phil
ad
elph
ia a
rea,
Pen
nsyl
vani
a.
A,
W. P
oste
l.
Min
eral
Zir
con.
___
..___
_
. .do
.....d
o _
_ . _
_
___ d
o _____
.....d
o _
____
__ .d
o _
___ ._
Mes
h siz
e
-80
+4
00
-80+
400
-80
+4
00
-80
+4
00
-80+
400
-80
+4
00
aper
mg
pe
rhr
297
288
240
247
220
250
Lea
d (p
pm)
Det
erm
inat
ions
25.2
8
25,2
6
28,3
0
24,2
5
20,2
3
22,2
5
Mea
n
26.5
25.5
29 24.5
21.5
23.5
Lea
d-
alph
a ag
e In
m
illio
ns
of y
ears
218
216
293
24:1
238
230
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pos
t-P
reca
mbr
ian.
P
oste
l an
d Ja
ffe.
19
57.
Do.
Do.
Do.
Do.
Do.
to o s
to8
to a> to
b^ * *di? ^
Ll^I?
S'^8,S ^jg ^«j ^4 CD «T CD * j8 § <
toCO
O>gJ»
bOCfto
to CnCO
to en00
ff>2> &>&> %>& R -*»* ?* __ ? ^* <-"' *? ^*t<-"
g o go
$$?-' W
&g *"
1* S £° ^
KM- « "0^3sMl^sjuSg^plSI^Si H^&Slsfcl'^l^*!*?:^ 5-0 |-derM£".>S-o hj<! «P<fovi £ <j £; 00 CD S K K "-"OOrtrJ^ « 00 > fiT^ <3 fff^HpSS C*ct->-)t;M i-'Ict-^wj'" i-i3^.(f.S S S2.P ^n> 5 P B a o> 5 3i-j 5?
§IT
I*e-
o 2.
§KE? 5-fiT?-
»g51"
prg
ts-
toO O
I 00O
sO0O
8OCO-J
Oto
COtoO
p to H* a> oo "o0000 0
<i i 1Cn O
COo
00 co -a Cn CnCO I-1 00 tO IO0 *» 0, <K> <K>
I?
si o w o o S.B o o o o <ra g* o 2.
toi 'toCO
toto
to*Q
O O
to_totoCn
toCO
Cn
*>
00
^l_i I-HMC?
<! ct- *" 13 CD * < f
S P Pn"
e-8
Cfip'
8H snvaamw saoaNDi ,10aov
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
265
266
267
268
269
270
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Gra
nite
f el
soph
yre _
_ __ _ _
_C
M-2
. D
ike,
C
rab
Bot
tom
roa
d, 2
J^
mile
s no
rthe
ast
of
Hig
h-
tow
n, H
ighl
and
Cou
nty,
Va.
C
. M
ilton
. B
ento
nite
___ _ _
_ _ _
____
___
JTH
-2.
Vol
cani
c tu
ff,
7 fe
et a
bove
the
ba
se
of
the
Mar
tins
burg
sh
ale
near
Str
asbu
rg,
Va.
J.
T.
Hac
k.
Met
arhy
olit
e of
Cat
octi
n fo
r
mat
ion.
Pa
-Sm
-fr.
S
outh
M
ount
ain,
F
rank
lin
Cou
nty,
Pa.
R
. S.
Can
non.
54J-
1.
U.S
. H
ighw
ay 2
11,
1.6
mile
s w
est o
f Spe
rry v
ille,
Va.
H
. W
. Ja
ffe.
G
ray
gran
odio
rite
gne
iss.
___
__V
R-1
. O
ne
and
seve
n-te
nths
m
iles
wes
t of S
perr
y vill
e, V
a.
R.
S.
Can
non,
H
. W
. Ja
ffe,
K
. J.
Mur
ata,
G. N
euer
berg
, an
d G
. H
. E
spen
shad
e.
Old
Rag
Gra
nite
________
OR
-1.
Min
eral
Zir
con.
.___
_ _
_
___ d
o _
__
__
___ d
o _
__
__
-_..
do
_ .__
_
.do _
_
-
Mes
h si
ze
-80
+2
00
-200+
400
-100+
400
-100+
200
-100+
200
-100+
200
-80+
200
a pe
r mg
perh
r 23
106 37 686
854
8,78
6
533
530
725
1,13
3
Lea
d (p
pm)
Det
erm
inat
ions
3. 0
, 3. 0
15,1
6
7. 0
, 8. 0 13
5 16
0
2,00
0
116
113
125,
128
20
0, 2
05
Mea
n 3.0
15.5
7.5
126
202
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
310
355
484
470
445
465
508
510
417
42$
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pos
t-S
ilur
ian.
B
utts
, 19
33.
Mid
dle
to L
ate
Or-
do
vici
an.
But
ts,*
19
33.
Ear
ly C
ambr
ian
or
Pre
cam
bria
n.
Ree
d, 1
955.
Pre
cam
bria
n.
J. C
. R
eed,
Jr.
Do.
Do.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 115
o fi
O-6
I s<5111 3*-
PM
fiOft ft
8 8(N
oCO (N
00
3
T 1
«5
CDCO
t^ ocCO tf.
CO
) C> u:
<M
^
2cq ?
) 1O >O« ^w p"
CM
CO
oCO 00
cT55
O O
CM
o oo oCM CM+ +
CO 00I I
s
J .90
3 oN
1
8 fr "3 fl r-^ S®9
§ .PQ
!fi 1
te
son.
Henderson gra 54-O1r-207.
Rutherford County, N.C.
W. C. Overstreet.
Biotitic Whiteside granit
55Nc-7.
fourths rs, N.C.
ee- hi4S
OS sg
3 I? H ^
g(M
Lead
-alp
ha a
ge d
eter
min
atio
ns o
f acc
esso
ry m
iner
als
Con
tinu
ed
No.
277
278
279
280
281
282
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Bio
titi
c W
hite
side
gra
nite
__ _
55-N
C-5
.O
n U
.S.
Hig
hway
64
, no
rth
edge
of
Hig
hlan
ds,
N.C
. W
. R
. G
riff
itts.
55-N
C-4
. Fi
ve m
iles
wes
t of
Hig
hlan
ds,
N.C
. W
. R
. G
riff
itts.
55-N
C-3
. Fi
ve m
iles
wes
t of
Hig
hlan
ds,
N.C
.W
. R
. G
riff
itts.
B
esse
mer
gra
nite
__
. __
____
__50
L-1
74.
Tw
o an
d si
x-te
nths
m
iles
nort
heas
t of
Bes
sem
er C
ity.
N
.C.
W.
C.
Ove
rstr
eet.
Peg
mat
ite
intr
usiv
e in
to
To-
lu
ca q
uart
z m
onzo
nite
. 49
-Ot-
16.
Acr
e ro
ck
quar
ry,
Cle
vela
nd
Cou
nty,
N.C
. W
. C
. O
vers
tree
t. T
uloc
a qu
artz
mon
zoni
te__
___
49-O
t-14
. A
cre
rock
qu
arry
, C
leve
land
C
ount
y, N
.C.
W.
C.
Ove
rstr
eet.
Min
eral
Mon
azite
____
___
Zir
con_
___
..___
_
Mon
azite
_
Mes
h si
ze
-80+
200
-80
+2
00
-80+
200
-80
+2
00
-100+
200
-10
0+
20
0
-100+
200
-100+
200
a pe
r mg
perh
r
4,32
1
3,90
9
3,60
0
241
620
456
452
5,68
5
450
Lea
d (p
pm)
Det
erm
inat
ions
770,
765
780,
790
770,
760
71,7
5
130,
125 81
82
1,05
0 83
Mea
n
768
785
765
73 127
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
365
415
437
705
491
427
435
380
440
Cite
d ge
ologic
age o
f the
ro
ck
Pale
ozoi
c.
Gri
ffit
ts
and
Ove
rstr
eet,
1952
.
Do.
Do.
Do.
Do.
Do.
283
284f
285
286
287
288
289
290
Peg
mat
ite,
int
rusi
ve i
nto
To
luca
qua
rtz
mon
zoni
te.
53-O
t-14
. A
cre
rock
qu
arry
, C
leve
land
Cou
nty,
N.C
. W
. C
. O
vers
tree
t.
Tol
uca
quar
tz m
onzo
nite
, la
teph
ase
dike
. 49
-Ot-
22.
Qua
rry
at H
olli
s,
Rut
herf
ord
Cou
nty,
N.C
. W
. C
. O
vers
tree
t.
of t
he t
ype
foun
d ne
ar T
o
luca
. 47
-Mt-
73.
Eig
ht-t
enth
s m
ile N
.11°
W.
of
Tol
uca,
C
leve
land
C
ount
y,
N.C
. J.
B.
Mer
tie.
SO
Y-3
28.
She
lbv
area
, N
orth
C
arol
ina.
R
. G
.'Yat
es.
A48
-Ot-
81.
She
lby
area
, N
orth
C
arol
ina.
W
. C
. O
vers
tree
t.
Sch
ist
of C
arol
ina
gnei
ss__
___
48-O
t-81
. S
helb
y ar
ea,
Nor
th
Car
olin
a.
W.
C.
Ove
rstr
eet.
50-Y
-538
.S
helb
y ar
ea,
Nort
h C
arol
ina.
R
. G
. Y
ates
. S
chis
t of
Car
olin
a gn
eiss
_
__50
-Ot-
441.
S
helb
y ar
ea,
Nor
th
Car
olin
a.
W.
C.
Ove
rstr
eet.
Mon
azit
e _ _
___
Zir
con.
___
____
_
Mon
azit
e __ _
__
Zir
con.
___
____
_
Zir
con.
___
____
_M
onaz
ite _
___
_
Mon
azit
e _ _
___
-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
7,06
8
6,66
6
231
4,58
3
257
5,298
233
4,66
0
4,57
3
1,000
124
1,290
1,020 34 890 45
1,000 38 910
920
377
456
377
310
356
400
420
380
393
395
41 ?
Do.
Do.
Do.
Pre
cam
bria
n(?)
. G
riff
itts
and
O
vers
tree
t,
1952
.
Do.
Do.
Do.
Do.
O I o
d 00 GO
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
erals
Con
tinu
ed
No.
291
292
293
294
295
296
Koc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Hom
ogen
eous
fo
liat
ed
Cra
n
berr
y gn
eiss
, sa
prol
ite.
C
-l.
Spr
uce
Pin
e di
stri
ct,
Nor
th
Car
olin
a.
W.
R.
Gri
ffit
ts.
Hom
ogen
eous
fo
liat
ed
Cra
n
berr
y gn
eiss
, sa
prol
ite.
C
-2.
Spr
uce
Pin
e di
stri
ct,
Nor
th
Car
olin
a.
W.
R.
Gri
ffit
ts.
Gra
nito
id b
and
in a
ugen
gne
iss.
R
G-2
. D
ellw
ood
quad
rang
le,
Hay
- w
ood
Cou
nty,
N.C
. R
. G
olds
mit
h.
Mic
a sc
hist
of
Car
olin
a gn
eiss
. _55N
C 2
O
n U
.S.
Hig
hway
64,
6.3
mile
s ea
st o
f F
rank
lin,
N.C
. W
. R
. G
riff
itts
. M
ax P
atch
gra
nit
e.. _
____
____
MP
-1.
Lem
on G
ap q
uadr
angl
e,
Max
P
atch
Mou
ntai
n, T
enn.
R
. G
olds
mit
h,
D.
Car
roll
, R
. B
. N
eum
an.
Are
nite
. _ _
____
____
____
____
__R
N-2
.O
coee
se
ries
, G
reat
S
mok
y M
ounta
ins,
G
atl
inb
urg
qu
adra
ngle
, T
enne
ssee
. R
. B
. N
eum
an.
Min
eral
Zir
con.
_ __
____
_
_.__
_do_
____
____
__
do.
_ d
o __
_ _
do._
_______
Det
rita
l zi
rcon
(f
resh
),
(met
amic
t)..
_
Mes
h si
ze
-80 +
200
-80+
200
-80+
200
-200+
400
-60+
200
-80
+2
00
-80+
200
-80+
200
a pe
r m
g per
hr 90
38
457
472
129
218 78 124
287
Lea
d (p
pm)
Det
erm
inat
ions
18,2
0
7. 0
, 8.
0
102
105
33,3
5 53
,55 31
58,5
9
104,
110
Mea
n
19 7.5
34
54 58.5
107
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
503
4:7
1
531
529
620
587
910
1,07
0
855
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pre
cam
bria
n (?
) .
Gri
ffit
ts a
nd
Ove
rstr
eet,
195
2.
Do.
Pre
cam
bria
n.
R.
Gol
dsm
ith.
Pre
cam
bria
n.
W.
R.
Gri
ffit
ts.
Pre
cam
bria
n.
R.
Gol
dsm
ith.
Lat
e P
reca
m
bria
n (?
) .
Kin
g,
1949
; C
arro
ll,
Neu
man
, an
d Ja
ffe,
195
7.
00
M GO s o o a o « o t-1 o 3
LEAD-ALPHA AGE DETEEMINATIONS OF IGNEOUS MINERALS 119
COto0
on oft
* o
ft oftoft
rj .&Is-" c'G-°*° T'ccW
o o«-- o I O>
00 l> US O
a> a> »o o
(NCO CO
O5
o00o"
ooCO
o o<N <N
oo<N
O O
O CO
o oCO CO § O
CO
IoCO
3*1 aI61
a o o
.53
1§ia ^ M
OJ t, OJaj 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-Cfl m - aj
..08 «|> fl
«sl§|5J -r .51- 5
2w ^'S I ® *
«<P501^ l)| I:
PiP^HP^
i>o>(M
CO O5 <N
i(N
O
§§ CO
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
erals
Con
tinu
ed
No.
303
304
305
306
307
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
TB
56-1
1.
Peg
mat
itic
ne
st,
bord
er
of
ilmen
ite n
orit
e an
d an
orth
o-
site
, co
ordi
nate
s Y
21
536
and
X
3705
7,
Tel
lene
s,
Han
ge
i D
alan
e,
sout
hern
N
orw
ay.
T.
F.
W.
Ear
th.
Peg
mat
ite _
__ _
___
____
____
_T
B-1
. M
elko
doel
a, B
ygdi
n, s
outh
ern
Nor
way
. T
. F
. W
. B
arth
. P
egm
atit
e56
-1.
Stj
erno
, F
inm
ark,
so
uthe
rn
Nor
way
. T
. F.
W.
Bar
th.
Peg
mat
ite.
_
____
__
____
TB
-3.
Dik
e in
ba
sic
igne
ous
rock
, S
karv
aan,
Sei
land
, no
rthe
rn
Nor
way
. T
. F.
W.
Bar
th.
TB
-6.
Dik
e in
ig
neou
s ba
sic
rock
, Sk
arvb
ergn
es,
Seila
nd, n
orth
er
n N
orw
ay.
T.
F. W
. B
arth
.
Min
eral
____
_do_
____
___-
do
____
_do_
-___
____
__
__
_d
o-_
----
_
Mes
h si
ze
+ 6
0
+ 6
0
+ 6
0
+ 6
0
+ 6
0
a pe
r mg
perh
r 86 211 27 88 31
Lea
d (p
pm)
Det
erm
inat
ions
14,1
5 51
6.0
6.3 36 13
Mea
n
14.
5
6. 1
5
Lea
d-
alph
a ag
e In
m
illio
ns
of y
ears
405
573
541
930
957
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Ord
ovic
ian-
Silu
rian
H
olte
dahl
, 19
53.
Do.
Do.
Do.
Do.
308
309
310
311
312
313 »I
So
vit
e.. _
___
___ _
-__
- --
TB
-8.
Fen
are
a, s
outh
ern
Nor
way
. T
. F
. W
. B
arth
.
TB
-2.
Dik
e in
mig
mat
itic
gne
iss,
Fen
ar
ea,
sout
hern
Nor
way
. T
. F
. W
. B
arth
. G
rani
te _
__
__
__--
--_--
---
EI-
1.
Rov
anie
mi,
Fin
land
. E
. In
gers
on.
EI-
2.
Sal
onen
kala
, F
inla
nd.
E.
Inge
rson
.
EI-
3.
Bod
om,
Fin
land
. E
. In
gers
on.
Z-6
1.
Z-^S
a.
Z-l
. Z
-3.
Z-2
. Z
-2L
. Z
-4.
Z-4
a.
Z-S
b.
Z-S
c.
Z-6
3.
Z-6
3L.
Intr
usiv
e in
to Q
uana
h gr
anit
e,
Qua
nah
Mou
ntai
n, W
ichi
ta
Mou
ntai
ns,
Okl
a.
F.
L.
Hes
s, R
. L
. D
ott
. Je
an le
ad-a
lpha
age
(Okl
ahom
a zi
rcon
) of 1
---_
.do
_-_
_ ..
_. -_
_do.
__ .._
...
---.
do
.__
__
.._
_
-___-d
o -
__ _
Zir
con
(met
a-
mic
t)
Th
:U=
0.3
r 9
<\
7<\
fc=
1.77
X10
-*
Zir
con
(fre
sh)
Th:U
=3
c=2,
350
k -1
. 22X
10-*
.Z
irco
n (m
eta-
m
ict)
T
h:U
=4
c=2
,30
0
fc=
1.12
X10
-*
To. 3
13 Is
619
mill
ions
of
-60+
200
-60+
200
-60
+2
00
-60
+2
00
-80+
400
30 m
mcr
ysta
ls.
rear
s.
102 57 303
374
160
150
146
157
184
168
170
326
151
1,10
3 1,
292
1,22
0 1,
270
1,18
0 1,
230
1,19
0 1,
168
19, 2
0, 1
9, 2
1 18 100
118 52 101
101
103
120 43
45
88
41
290
350
335
380
340
360
343
339
2046
5
730
767
735
757
1,45
0 1,
510
1,45
0 1,
440
579
59S
610
618
585
601
610
66#
635
645
637
'64#
No
dat
a.
T.
F.
W.
Bar
th.
Lat
e P
reca
mbr
ian.
T
. F
. W
. B
arth
.
Pre
cam
bria
n.
A.
Kah
ma.
Do.
Do.
Lat
e P
reca
mbr
ian.
T
aylo
r, 1
915.
§ CO l^J I GO
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
era
ls C
onti
nued
No.
314
315
316
Roc
k ty
pe
Fiel
d N
o.
Loc
ality
C
olle
ctor
Tis
hom
ingo
gra
nite
, po
rphy
ri-
tic
gran
ite.
T
en A
cre
Roc
k, 8
mile
s no
rth
w
est
of
Tis
hom
ingo
, A
r-
buck
le M
ount
ains
, O
kla.
W
. B
. H
amil
ton.
G
em-b
eari
ng
grav
els
pres
um
ably
de
rive
d fr
om
pegm
a
tite
-Cey
lon.
Z
-l.
Z-2
. Z
-4-3
3.
Z-3
-16.
Z
-5-1
. Z
-4-3
6.
Z-3
-11.
Z
-3.
Z-3
-42.
Z
-2-3
7.
Z-2
- 13.
Z
-4.
Z-2
-18.
Z
-2-2
3.
Z-6
. Z
-2-1
7.
Z-7
. Z
-9.
Z-l
-2.
Z-1
0.
Z-l
-26.
G-2
117.
Min
eral
Zir
con_
____
____
Zir
con
Th
:U=
<0.1
c =
2,6
32
fc=
1.9X
10-*
.
Mes
h si
ze
-60+
400
Lar
ge
crys
tals
.
-60
+2
00
a pe
r m
g pe
r hr 72
80 10
3 27
3 15
0 35
2 38
0 43
0 53
3 64
3 64
9 65
2 85
0 88
2 91
3 98
5 1,
185
1,24
5 1,
583
1,81
5 2,
040
2, 1
97
2,21
0 34
4 35
8
Lea
d (p
pm)
Det
erm
inat
ions
28,3
0 29
,31 22
65
37
80
88
91
11
5 15
0 14
3 14
8 19
6 20
5 20
0 22
7 27
5 27
0 39
2 45
0 44
0 52
9 49
8 75
85
Mea
n
29
30
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
922
845
53*
590
609
565
575
527
536
578
548
._
56S
57S
576
545
572
570
535
61S
61S
530
594
560
519
562
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pre
cam
bria
n.
Ham
ilto
n, 1
956.
Pre
cam
bria
n.
Wad
ia a
nd F
er
nand
o, 1
944.
Lat
o P
reca
m
bria
n.
C.
E.
Til
ley.
317
318
319
320
321
322
Tam
bane
, N
yasa
land
, A
fric
a.C
. E
. T
ille
y.
T-l
.T
amba
ne,
Nya
sala
nd,
Afr
ica.
C
. E
. T
ille
y.
Peg
mat
ite _
__
___
___ _
.__
6208
1.
Tam
bane
, N
yasa
land
, A
fric
a.
C.
E.
Til
ley.
F
ayal
ite
ferr
ohed
enbe
rgit
egr
anit
e.
H-3
. C
ranb
erry
L
ake
quad
rang
le,
Adi
rond
ack
Mou
ntai
ns,
N.
Y.
A.
W.
Pos
tel.
Haw
keye
gr
anit
e gn
eiss
____
__P
-3.
Mud
Lak
e M
ount
ain
quar
ry,
Loo
n L
ake
quad
rang
le,
Adi
ro
ndac
k M
ount
ains
, N
.Y.
A.
W.
Pos
tel.
Lyo
n M
ount
ain
gran
ite _
___
_P
-l.
Adi
rond
ack
Mou
ntai
ns,
Dan
- ne
mor
a, N
.Y.
A.
W,
Pos
tel.
Hor
nble
nde
mic
rocl
ine
plag
io-
clas
e gr
anit
e gn
eiss
. 18
8.
One
hu
ndre
d se
vent
y-fi
ve
yard
s so
uthw
est
of
Sto
ne
scho
ol,
Rus
sell
qu
adra
ngle
, A
diro
ndac
k M
ount
ains
, N
. Y
. A
. F
. B
uddi
ngto
n.
-___
_do_
____
_._.
Mon
azit
e _
_ _
Zir
con
____
____
_--
_.d
o,-
_--
_._
-
-___do_._
__
_,_
_
-____dO
----
__-_
+ 6
0
+ 6
0
-60
+2
00
-60 +
200
380
489
185
375
1,63
4 73 185
187
215
213
285
86 105 47 85 430 17 51
48,5
1 48
,48 60 60 75
48
537
51 ?
600
53S
539
55S
64£
GO?
656
660
621
Do.
Do.
Pre
cam
hria
n.B
uddi
ngto
n,
1939
.
DC
.
Do.
Do.
OQ
O CO
Lea
d-al
pha
age
dete
rmin
atio
ns o
f ac
cess
ory
min
era
ls C
onti
nued
No.
323
324
325
326
Roc
k ty
pe
Fie
ld N
o.
Loc
ality
C
olle
ctor
191.
S
tark
com
plex
, 1.
5 m
iles
wes
t-
nort
hwes
t of
C
oldb
rook
sc
hool
, S
tark
qu
adra
ngle
, A
diro
ndac
k M
ount
ains
, N
. Y
. A
. F
. B
uddi
ngto
n.
Pyr
oxen
e ho
rnbl
ende
gr
anit
e gn
eiss
. 12
4.
Gar
neti
fero
us g
ranu
lite
fac
ies,
T
uppe
r L
ake
quad
rang
le,
Adi
rond
ack
Mou
ntai
ns,
N.
Y.
A.
F.
Bud
ding
ton.
P
arag
neis
s. _
____
_ __
____
____
229.
S
even
-ten
ths
of a
mile
nor
th
east
of
road
to G
olde
n B
each
on
R
aquet
te
Lak
e qu
ad
rang
le.
Adi
rond
ack
Mou
n
tain
s, N
.Y.
A.
F.
Bud
ding
ton.
248.
R
aque
tte
Pon
d, s
outh
wes
t en
d of
T
uppe
r L
ake,
A
diro
n
dack
M
ount
ains
, N
.Y.
A.
F.
Bud
ding
ton.
Min
eral
_ _
_do_
_ _ -_
__
_
do_ _
.
-__.
_do_
____
___-
Mes
h si
ze
-60 +
200
-60 +
200
-60 +
200
a pe
r m
g pe
r hr 18
8
101
130
134
Lea
d (p
pm)
Det
erm
inat
ions 50
30,2
9
34,3
6
35,3
7
Mea
n
29
.5
35
36
Lea
d-
alph
a ag
e in
m
illio
ns
of y
ears
627
69ff
634
63S
Cite
d ge
olog
ic a
ge o
f the
ro
ck
Pre
cam
bria
n.
Bud
ding
ton,
19
39.
Do.
Do.
Do.
LEAD-ALPHA AGE DETERMINATIONS OF IGNEOUS MINERALS 1 25
California ContinuedUbehebe quadrangle.__________________________________________ 129Yosemite National Park________________________________ 131,132,133
New JerseyBeemerville_________._-_-__-__.______________ 249, 250, 251Dover__________________________________________________ 342New Jersey Highlands----.--------.-.----------------------- 340, 341
New MexicoBig Hatchet Peak quadrangle._----__-___--__-__-------------_-- 363Cerrillos Hills______________._.______________ 25Hachita quadrangle__________________________________________ 49Los Pinos Mountains-_________________________________________ 365Sangre de Cristo Range._-__--_-_-___-__-________-__-__-_--_-_- 364Santa Fe County..__________________________-____-_-_--_-_.- 10Valles Mountains______--______-_______-________-_-__-_----__ 13
New YorkAdirondack Mountains
Ausable Forks____________.,______________--_______-__--- 334Big Moose quadrangle.-______-______-__-_._-________-__-_-_- 337Cranberry Lake quadrangle __-_________________----------- 319, 333Dannemora. ________________________________________________ 321Harrisville bridge__________________________________________ 335Loon Lake quadrangle--______--______-_-_________--_--_-___- 320Natural Bridge__________________________________________ 331Oswegatchie quadrangle.___________________________________ 327, 328Raquette Lake quadrangle_---______________..-_-_-_-_--_-_-_ 325Russell quadrangle_________________________________________ 322Santa Clark quadrangle.--__-_--__________-___-________----_- 332Stark quadrangle..______________________________________ 323, 336Tupper Lake________.__._.___________________ 326, 339Tupper Lake quadrangle--------____________-_-_.-_ 324, 329, 330, 338
Wyoming Cumberland Gap area________________________________________ 353Fremont County..______________________________ 349, 350 Grass Creek area_________________________________ _________ 352Rock Spring area_____________________________________-____._-_ 354
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