GEOLOGICAL SURVEY CIRCULAR 331 

RECONNAISSANCE FOR 

RADIOACTIVE DEPOSITS 

IN EASTERN INTERIOR 

ALASKA, 1946 

This report concerns work done on 

behalf of the U.S. Atomic Energy 

Commission and is published with 

the permission of the Commission. 

UNITED STATES DEPARTMENT .OF THE INTERIOR 

DouglaE? McKay, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

GEOLOGICAL SURVEY CIRCULAR 331 

RECONNAISSANCE FOR-RADIOACTIVE DEPOSITS IN EASTERN INTERIOR 

ALASKA, 1946 

By Helmuth W edow, Jr., P. L. Killeen, and others 

This report concerns work done on 

behalf of the U.S. Atomic Energy 

Commission and is published with 

the permission of the Commission. 

Washington, P. C., 1954 

Free on application to the Geological Survey, Washington 25, D. C. 

CONTENTS 

·CHAPTER A. -Areas adjacent to highways in the 

Tanana. and upp,er Copper River valleys, by 

Helmuth Wedow, Jr., and J. J. Matzko 

Page 

Abstract.·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Measurement of radioactivity. . . . . . . . . . . . . . . 2 

Outcrop tests ........... : . . . . . . . . . . . . . 3 

Unconcentra.ted crushed samples . . . . . . . . 3 

Concentrated samples. . . . . . . . . . . . . . . . . . 3 

Areas investigated. . . . . . . . . . . . . . . . . . . . . . . . . 3 

Fairbanks district . . . . . . . . . . . . . . . . . . . . . 3 

Geology.......................... 3 

Radioactivity studies in the 

Pedro Dome area.. . . . . . . . . . . . . . . . 6 

Radioactivity studies in the 

Ester Dome area... . . . . . . . . . . . . . . . 7 

Steese Highway belt in upper 

Cha.ta.nika. valley. . . . . . . . . . . . . . . . . . . . . 8 

Geology.......................... 8 

Radioactivity studies. . . . . . . . . . . . . . . 8 

Livengood area ..... , .... .- ...... ,'. . . . . . 8 

Geology .......................... 11 

Radioactivity studies ........... :. . . 11 

Harding Lake-Richardson area.:........ 11 

Geology . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Radioactivity studi'es. . . . . . . . . . . . . . . 13 

Alaska. Highway belt ....... ~ ........... 13 

Geology .......................... 13 

Radioactivity studies. . . . . . . . . . . . . . . 13 

CHAPTER A. -Areas adjacent to highways in the 

Tanana and upper Copper River valleys-Con. 

Areas investigated-Continued 

Alaska. Highway belt-Continued 

Radioactivity studies-Continued 

Localities northwest of 

Page 

Tok Junction. . . . . . . . . . . . . . . . 13 

Localities southeast of 

Tok Junction. . . . . . . . . . . . . . . .. 16 

Highway area. between Slana and 

Tok Junction . . . . . . . . . . . . . . . . . . . . . . . 16 

Geology .......................... 16 

Radioactivity studies.. . . . . . . . . . . . . . 16 

Donnelly Dome-Paxson area ... : ........ 18 

Geology .......................... 18 

Radioactivity studies . . . . . . . . . . . . . . 18 

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

Literature cited. . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

CHAPTER B. -Grant Creek area, by · 

P. L. Killeen and M. G. White 

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

Purpose and scope of investigation . . . . . . 33 

Location of area. . . . . . . . . . . . . . . . . . . . . . . 33 

Geology .................................. 33 

Radioactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

Locations of tests . . . . . . . . . . . . . . . . . . . . . 33 

Conclusion ............................... 35 

Literature cited. . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

ILLUSTRATIONS 

Page 

Figure 1. Index map to areas investigated along the highways in the Tanana. and upper Copper River 

valleys, Alaska ............. : .............................. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

2. Diagram showing relationship between the equivalent uranium content of unconcentrated crushed· 

samples and outcrop gamma counts.......................................................... 4 

3. Geologic sketch map of the Pedro Dome area., Fairbanks district. .................... ,. . . . . . . . . . . . . 5 

4. Topographic sketch map of the Ester Dome area.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

5. Geologic sketch map of the Steese Highway belt in the upper Cha.tanika valley. . . . . . . . . . . . . . . . . . . . . . 9 

6. Geologic sketch map of the Livengood area ............................................ · ........ ·. 10 

7. Geologic sketch map of the Harding Lake-Richardson area, Richardson Highway................... 12 

8. Geologic sketch map of the Alaska. Highway belt, upper Tanana. valley.. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

9. Geologic sketch map of the highway area between Slana and Tok Junction. . . . . . . . . . . . . . . . . . . . . . . . . . 17 

10. Geologic sketch map 'of the Donnelly Dom~-Pa.xson area, Richardson Highway . . . . . . . . . . . . . . . . . . . . . 19 

11. Drainage map of the Grant Creek area, Yukon region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

TABLES 

Page 

Table 1. Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River 

valleys., Alaska ............................................................................ 21 

2. Data on placer concentrates from Grant and Tozimoran Creeks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

RECONNAISSANCE FOR RADIOACTIVE DEPOSITS IN EASTERN INTERIOR 

ALASKA, 1946 

By Helmuth Wedow, Jr., P. L. Killeen, and others 

CHAPTER A. -AREAS ADJACENT TO HIGHWAYS IN THE TANANA AND UPPER COPPER RIVER VALLEYS 

By Helmuth Wedow, Jr., and J. J. Matzko 

ABSTRACT 

A reconnaissance conducted in 1946 in areas 

adjacent to highways in the Tanana and upper 

Copper River valleys was the first time that field 

radioactivity tests were made in eastern interior 

Alaska. Before 1946 the scanning of the Alaskan 

placer-concentrate collection of the Geological 

Survey for radioactivity had indicated that radioactive minerals occurred in a few localities in 

the Fairbanks and Livengood areas. The objectives 

of the 1946 reconnaissance were to determine 

whether significantly radioactive lodes occurred in 

the vicinity of the placers from which the radioactive concentrates had been obtained and to conduct a routine survey for radioactive deposits in accessible areas adjacent to highways in eastern interior 

Alaska. The techniques used in the survey consisted of the direct testing of outcrops for radioactivity with a portable survey meter and the 

collection of rock samples and placer concentrates 

for equivalent uranium analysis in the laboratory. 

Although the 1946 reconnaissance did not 

yield any further information on the source of the 

few concentrates of higher radioactivity that had 

been obtained previously, a few new sites of 

radioactivity were found. Data for all sites, regardless of favorable or unfavorable results, are 

presented in order that future investigators may 

evaluate how thoroughly negative areas have been 

determined. Lode deposits, consisting primarily 

of quartz veins containing gold and metallic 

sulphides, contain only as much as 0. 005 percent 

equivalent uranium. Graphitic schists and black 

shales contain a maximum of 0. 004 percent equivalent uranium; other ,types of schist contain only 

as much as 0. 003 percent equivalent uranium .• 

Tests of granitic and mafic igneous rocks indicate 

maximums of 0. 006 and 0. 005 percent equivalent 

uranium respectively. Concentrates from placer 

deposits, locally contain as much as 0. 066 percent 

equivalent uranium. 

The slight radioactivity of the igneous rocks 

appears to be due to traces of uranium and 

thorium in such accessory minerals as zircon and 

allanite. The slightly higher radioactivity of the 

placer samples at some localities is probably due 

to the natural concentration of the radioactive 

zircon and allanite. At a few localities, monazite 

has been found in the placers and probably also 

1 

contributes to the radioactivity of the concentrates. 

Its bedrock occurrence is doubtless also as an 

accessory mineral in the granitic rocks. 

INTRODUCTION 

The Tanana and upper Copper River valleys 

in eastern interior Alaska (fig: 1) are on opposite sides of the Alaska Range. The Tanana 

River, on the north side of the range, flows 

northwest into the Yukon River, and the Copper 

·River, on the south side, flows south into the 

Gulf of Alaska. The principal highways in Alaska 

either follow these two valleys or· cross the 

intervening uplands. These highways and subsidiary 

roads are shown on figure 1. 

The initial scanning of an Alaskan placersample collection for radioactivity in the winter 

of 1944-45 indicated· a few sites in the Fairbanks 

and Livengood areas where radioactive materials 

were present in stream deposits. Subsequent field 

sampling by R. R. Coats in 1945, during a 

reconnaissance of the Yukon-Tanana placer region 

{Fortymile, Circle, Fairbanks, and Livengood 

districts), increased the number of samples available from these areas,· but did not reveal any 

additional sites of. significantly radioactive material. 

Information on those samples which were available 

before the 1946 reconnaissance in the Tanana and 

upper Copper River valleys is summarized in an 

informal file report by P. L. Killeen on trace 

elements investigations in Alaska and is reproduced 

below. 

Radioactivity of samples collected before 1946 in the 

Tanana and upper Copper River valleys, Alaska 

Total Number of samples in each of 

District number three ranges of percent Not 

of equivalent uranium teste d 

samples >0.02 0.02-0.01 <0.01 

Tolovana-- 53 2 0 34 

Fairbanks- 148 4 3 89 

In 1946, a reco<~laissance for radioactive 

deposits in areas accessible from the highways 

l 

5 

7 

2 

in the Tanana and upper Copper River valleys 

was undertaken because the accessibility permitted 
I 

50 

Bose from U.S. A.A. F. flight charts compiled by U.S. Geological Survey 

150 Miles 

Figure 1. -Index map to areas·investigated along the highways in the Tanana and upper Copper River valleys, Alaska. 

covering a large area in the course of the field 

season and because previous information on radioactivity in areas adjacent to highways in the 

Tanana and upper Copper River valleys was 

either sparse or absent. The reconnaissance 

party consisting of Helmuth Wedow, Jr., and 

John J. Matzke, geologists, and Fred Freitag, 

camphand, was in the field from June through 

September 1946. 

2 

MEASUREMENT OF RADIOACTIVITY 

The radioactivity of outcrops of bedrock and 

gravel, and of unconcentrated samples of.crushed bedrock.was measured in the field with a portable survey 

meter designed by the Geological Survey for the measurement of gamma-ray intensity. Tests on samples were made at base camps where readings were 

not influenced by any radiation from large areas of 
outcrop of the material sampled. Most of the rock 

samples were later crushed to minus 4-mesh in a jaw 

crusher at the Fairbanks laboratory of the Geological 

Survey. Subsequently, heavy-mineral separates of 

crushed rock samples, of panned concentrates of 

crushed rock samples, and of panned concentrates 

of gravels and weathered disintegrated rock materials 

were prepared and tested for radioactivity by beta count 

on a laboratory scaler in Washington. Table 1, at the 

end of this report, gives the location and description 

of each tes~ station, the radioactivity determinations 

made at the stations or on samples obtained therefrom, 

and the concentration ratio of the ultimate concentrate 

for which the radioactivity was measured. The radioactivity throughout is expressed in terms of percent 

equivalent uranium. 

Outcrop tests 

Outcrops of bedrock and gravel were tested 

for radioactivity by placing the probe on the surface of the material and measuring the gamma 

count for 5-rninute intervals. Background readings, 

with the probe several feet above the surface of 

the ground, were taken several times a day as 

a check. The results of the gamma count at each 

outcrop, as shown in table 1, is expressed in 

terms of percent equivalent uranium by interpolating 

from the diagram shown in figure 2. 

In the construction of such a. diagram (fig. 2) 

the average background counting rate of the instrument that was used was determined by a veraging the averages of groups of four consecutive-. 

backgrounds. The final average background was 

then plotted on the diagram a.s <0, 001 percent 

equivalent uranium. The equivalent-uranium values 

of a number of crushed samples were then plotted 

against the gamma cot.ints obtained a.t the outcrops 

from which the samples were taken. The diagonal 

line, showing the probable relationship between 

the equivalent-uranium value and the outcrop gamrna. count, was then drawn by inspection from the 

point where the average background was assumed 

to represent<O. 001 percent equivalent uranium. 

Deviation of points from the diagonal is attributed 

either to sampling errors or to the random nature 

·of gamma radiation over short periods of time. 

Unconcentrated crushed samples 

To determine the equivalent-uranium content 

of the crushed rock samples, 5-rninute readings 

of background, sample, a radioactive standard, 

sample, and background were made in that sequence. 

Concentrated samples 

To increase the proportion of heavy minerals 

to be tested for radioactivity at any one station, 

concentrates were made by panning unconsolidated 

materials such as stream gravel and slope wash, 

and disintegrated rock from mine dumps and 

weathered outcrops. Later, to obtain a. standard 

type of concentration, separations of minus 20-mesh 

3 

material were made with heavy liquids (bromoform, 

sp gr 2. 8; methylene iodide, sp gr 3. 3). The 

unconcentrated crushed samples were crushed 

further to minus 20-:mesh and also separated with 

heavy liquids. The percent equivalent uranium 

in the resultant heavy fractions was then determined 

by beta-gamma count with laboratory instruments. 

AREAS lliVESTIGA TED 

Fairbanks district 

The Fairbanks district, herein divided into 

the Pedro Dome area (figs. 1 and 3) and the 

Ester Dome area (figs. 1 and 4), includes about 

300 square miles of territory adjacent to the 

city of Fairbanks. 

The Pedro Dome area, from 5 to 25 miles 

northeast from Fairbanks, roughly includes the 

watersheds of the streams draining the area surrounding Pedro Dome and Gilmore Dome. The 

main streams are: Cleary, Little Eldorado, Dome, 

and Vault Creeks, ·north-flowing tributaries of the 

Chatanika River; Goldstream Creek and its westflowing tributary, Big Eldorado Creek; and 

Fairbanks, Fish, and Smallwood Creeks, tributaries 

of the Little Chena River. In 1946 mining camps 

were located in most of the major valleys, and 

many of the smaller streams had been mined 

previously. The Steese Highway, crossing the 

area in a general northeasterly direction, has its 

origin at Fairbanks and leaves the area shown 

in figure 3 via the valley of Cleary Creek. The 

Elliott Highway, or Livengood road, diverges from 

the Steese Highway at Fox. Many secondary roads 

and trails lead from the main highways to sites 

of past and present mining operations. 

The Ester Dome area, 10 to 15 miles west 

from Fairbanks, is drained by tributaries of 

Goldstream Creek on the northwest and by tributaries of Cripple Creek on the southeast. In 

1946 the area was accessible by a graded gravel 

road from Fairbanks, and by m.any secondary 

roads and trails that branch out to lode and placer 

mining operations. A small settlement, Berry, P. 0., 

located on Ester Creek, is the center of the 

dredging operations of the Fairbanks Exploration 

Department, U. S. Smelting, Refining, and Mining 

Co., in the Ester Dome area. 

Geology 

The general geology of the Fairbanks district 

is relatively well known as a result of studies 

of its gold-bearing placers and lodes (Prindle, 

1905, 1908, 1910a, 1913; Ellsworth, 1910; Hill, 

1933; Mertie, 1937; and Capps, 1940). 

The Birch Creek schist of pre-Cambrian 

age is the bedrock underlying the larger part of 

the district. The schist is predominantly of 

sedimentary origin and has a considerable range 

of composition. The chief types, however, are 

quartz-mica and quartzite schist. Minor amounts 

of augen gneiss and crystalline limestone are 
0.007 

.006 

-c 

Q) 

(.) 

.005 "- 1---Q) 

a. 

c 

f--. 

E 

::J 

c 

c 

.004 f--."-::J 

-c 

Q) 

1---C 

.::: 

::J 

C" 

Q) 

.003 --. 

Q) 

a. _E 

c 

(J) 

-c 

.002 

Q) 

f--. ...c 

(J) 

::::J 

"- 0 

.001 

0.000 

0 10 

I 

I 

I 

I 

I 

0 I 

I 

I 

0 I 

0 ;-

I 0 

I 

v 

o/ 

I <) 

0 

I 

oo/ 0 

0 

0 f 

/ 0 

0 0 

v 

I 0 

,... '-' v '"' 

20 30 40 50 60 

Gamma count per minute on outcrop 

Figure 2. -Diagram showing relationship between the equivalent uranium content of unconcentrated crushed samples 

and outcrop gamma. counts. 

4 
<:r42 Outc.op test 

CJ-41 Outcrop test and unconcentrated sample 

C>-63 Outcrop test and concentrated sample 

• 62 Outcrop tnt, unconeentrated sample, 

and concentrated tample 

Numbert Indicate ttatlont prefixed 11P011 1n 

table I of text 

2 0 

Bose from u.s. Geological Survey Alatkcl Map 40 

6MIIes 

D 

AIIYvium 

E~~t: F'orphyrltie vranltt 

Quartz diorite 

Schltt 

pin ~r and crylfalllne auttn) o 

~ I ~ llrntttone; alta tome ~ 'f altered granitic dikes I:J f and mlneraUzed veins ::1 

Geology modified from U.S. GeoiQ91cal Survey 

Bulletin 849·8; minor uncantolldated 

dtpatlto eJWiuded 

l"leld work by Helmuth Wedow, Jr., and 

J. J. Motzko, June·July 1946 

Figure 3. -Geologic sketch map of the Pedro Dome area, Fairbanks district, Alaska. 

also present. Igneous rocks of two main types 

intrude the . Birch Creek schist. One is a quartz 

diorite, well exposed on Pedro Dome; the other 

is coarse·-grained porphyritic granite underlying 

a large area south and southwest of Gilmore 

Dome {fig. 3). In the vicinity of Ester Dome 

only a few small bodies of porphyritic granitic 

rocks have been reported. Minor types of igneous 

rocks, represented primarily by altered granitic 

5 

dikes, are numerous but scattered. All the igneous 

rocks are presumably Mesozoic in age. Known 

lode deposits in the Gilmore Dome watershed are mainly gold-quartz, bismuth, and tungsten 

veins and replacement bodies, all for the most 

part closely associated with the large intrusive 

mass of granite near Gilmore Dome. Extensive 

muck and gold-bearing gravel deposits cover most' of the valley bottoms and lower hill slopes. 
EXPLANATION Q6 ~29 

Outcrop test Unconcentrated sample 

~8 ~5 

Outcrop test orid concentrated sample Outcrop test and unconcentrated sample 

Numbers indicate stations prefiKed "ED" in table I of teKf 

0 SMiles 

Base from ll. 5. Geological Survey Alaska Map 40 Field work by Helmuth Wedow, Jr., 

and J. J. Motzko, June-July 1946 

.tt'igure 4. -Topographic sketch map of the Ester Dome area, Fairbanks district, Alaska. 

Barren windrows of dredge tailings are now conspicuous as ·a. result of placer mining in the valley 

bottoms of Goldstream, Gilmore, Pedro, Fish, 

Fairbanks, Cleary, and Ester Creeks. Slope 

wash and a heavy moss-cover make natural rock 

exposures on the hills a. rarity, except locally 

at the crests, where weathering has sculptured 

the bedrock l.nto odd castellated shapes. 

6 

Radioactivity studies in the Pedro Dome area 

Previous equivalent uranium determinations 

on placer concentrates, obtained chiefly from goldmining operations, showed that some radioactive 

material occurs in the Pedro Dome area. Seven of 

the concentrate samples had more than 0. 01 percent 

equivalent uranium. The creeks from which these 
more radioactive concentrates were obtained, and the 

determinations of equivalent uranium in the concen-

-trates, are given below. 

Alaskan Percent equivalent Concentrate Creek uranium 

file no. A1 B2 

355 Fish Creek---------------- 3 0.100 0,016 628 Yellow Pup---------------- .028 .oo4 

109 Gilmore Creek------------- .013 .oo4 

965 First Chance Creek-------- .029 --- 648c Seattle Pup--------------- 3 .096 .024 

163 Cleary Creek-------------- .013 .018 

989 Specific locality unknown- .014 --- 1

Determinations made about January 1945. 2Redetermined in April 1947. 3

Indicates sample considered too small for accurate determination. 

The first four streams in the above tabulation are 

parts of the watershed that surrounds Gilmore Dome. 

Cleary Creek and Seattle Pup are part of the watershed 

that surround::, Pedro Dome (fig. 3). 

The recent testing in the Pedro Dome area indicated no appreciable amount of radioactivity except 

for two samples as follows: 

(l) Sample 1398: 

Location: Station PD 107, near head of 

Rex Creek. 

Nature of sample: Heavier-than-bromoform fraction of panned concentrate 

from 50 pounds of gravel. 

Equivalent uranium content: o.o66 percent. 

Comparative data: Outcrop test, 

0,001 percent equivalent uranium. 

(2) Sample l538L: 

Location: Station PD 41, along west 

side of the Steese Highway in the 

valley of Twin Creek about 6 miles 

northeast of Fox. 

Nature of sample: Heavier-than-bromoform fraction of crushed vein material 

on dump of abandoned scheelite mine· 

Equivalent uranium content: 0,013 percent. 

Compa.ra ti ve data: Outcrop test, 

0.001 percent equivalent uranium; 

unconcentrated crushed sample, 

0.002 percent equivalent uranium. 

The radioactivity data of the remaining tests in 

the Pedro Dome area may be summarized as follows: 

(1) Outcrop tests (115 stations): 

Maximum equivalent-uranium content: 

0.003 percent. 

Average equivalent-uranium content: 

0,001 percent. 

(2) Unconcentrated cr~hed rock samples 

(4 samples): 

Maximum equivalent-uranium content: 

0.003 percent, 

Average equivalent-uranium content: 

0,002 percent. 

(3) Concentrated samples (35 samples): 

Maximum equivalent-uranium content: 

O,oo6 percent, 

Average equivalent-uranium content: 

0.0025 percent, 

7 

Zircon, some of which is probably uranium- or 

thorium-bearing, is the only mineral as yet identified 

in the concentrates of the Pedro Dome area, to which 

radi~activity can be ascribed. Thus, in most samples, 

the presence of radioactive zircon could account for 

the small increases in equivalent-uranium content 

when the heavy minerals are concentrated. It appears 

likely, however, that some other radioactive mineral 

or minerals also occur in the samples containing more 

than 0. 01 percent equivalent uranium. 

The concentrate from Fish Creek (sample 355) 

consists of few small nuggets obtained from a placer 

operation about 2! miles northeast of Gilmore Dome. 

Although the original radioactivity determinatio"n made 

in 1945 indicated 0. 1 percent equivalent uranium, a 

second test in 1947 showed only 0. 016 percent equivalent uranium. A qualitative spectrographic examination 

of one of the nuggets shows that the ma.:or elements are 

bismuth and silicon with the bismuth preponderant. 

The nuggets, therefore, are probably mostly native . 

bismuth with some eulytite or argicolite possibly 

present. The gold, listed among the minor elements 

in the examination, occurs as fine flakes and wires. 

Uranium and thoril~m are listed among those elements 

looked for but not found. One bismuth lode occurs in 

the Fish Creek watershed above the location of this 

concentrate. The lode is in a biotite granite on the 

spur along the east side ofMonte Cristo Creek. 

(Chapin, 1914, p. 330-331.) This lode was not investigated in the brief reconnaissance of the lodes in the 

Pedro Dome area, nor were concentrates taken downstream from it. 

Radioactivity studies in the Ester Dome area 

Five placer concentrates from the Ester Dome 

area that had been tested for radioactivity before 

the 1946 field season ranged from <0. 001 to 0. 002 percent equivalent uranium. Although such values are 

extremely low, the coverage represented by only five 

samples was so scant that it seemed desirable to test 

at least a few of the known lodes and collect a few 

additional placer concentrates from the area. The 

locations of the· tests are shown on figure 4, and the 

results are included in table 1. 

Structural conditions have limited the best metallic mineralization of the area to the southeast flank 

of Ester Dome, and, therefore, placer and lode mining 

activities have been restricted to this flank (Hill, 1933). 

Consequently, tests for radioactivity were similarly 

localized. 

Many of the mines and prospects in the Ester 

Dome area have long since been abandoned, and 

adits have collapsed ,and are overgrown. Of 

necessity, therefore, the testing of lodes was 

restricted to ore materials scattered through the 

mine dumps. All the known lodes are of the 

gold-quartz variety, and carry, in addition to free 

gold, varying amounts of primary sulphides. 

Arsenopyrite and stibnite form the bulk of these 

sulphides, but minor amounts of boulangerite, jamesonite, and covellite have been reported (Hill, 1933, 

p. · 120-152). Weathered· parts of the veins examined 

are much stained with oxides of iron, manganese, 

antimony, and arsenic. 
The radioactivity of materials tested in thi.s area ranged from <0. 001 to 0. 007 percent equivalent 

uranium. The maximum value was obtained in·the 

·heavier-than-bromoform fraction of a concentrate 

panned from 50 pounds of gravel from St. Patrick 

Creek (station ED 7, sample 1424). As in the 

Pedro Dome area, the slightly higher equivalenturanium values in the concentrates as compared 

to the outcrop test may be attributed to the proportional increase in radioactive zircon resultant 

from concentra.tion. 

Steese Highway belt in upper Chatanika valley 

The portion of the Steese Highway midway 

between Fairba.nks and Circle lies mainly in the 

upper or headwater part of the Chatanika valley, 

but extends north and east to the headwater portions of Bea.ver, Birch, and Preacher Creeks 

(figs. 1 and 5). As considered in this report 

and shown on figure 5 the belt adjacent to the 

highway is about 60 miles long and 15 miles wide, 

and ha.s an area of a.bout 800 square miles. The 

topoqraphy qenerally consists . of lonq even-topped . ridges with long, broad, lateral spurs separating 

wide, shallow valleys. The Steese Hiqhway 

enters the valley of the Chatanika River at the 

mouth of Cleary Cree~ apd follows the valley 

northeastwa.rd. At the head of McMa.nus Creek 

the highway crof:1ses the divide into the valley of 

Twelvemile Creek of the Birch Creek watershed. 

Short roads lead from the highway to the site of 

dredging operations on Nome Creek, and to other, 

smaller placer mines on Deep and Sourdough 

Creeks. Most of the short trails that start from 

the highway are for access to the U. S. ~melting, 

, Refining, and Mining Co. ditch. The upper Chatanika 

valley has few inhabitants. Those who live there are employed mainly in prospecting and mining, or in maintaining the U. S. Smelting, Refining, 

and Mining Co. ditch or the Steese Highway. 

Geology 

The geology of the eastern or upper part 

of the Chatanika valley is similar to that of the 

Fairbanks district. The Birch C;reek schist (see 

previous discussion under Fairbanks district) is 

again the major bedrock of the area. A large mass of intrusive granitic rock of Mesozoic(?) 

age crops out in the north-central part of the area in the headwater portions of Nome Creek, 

and tributaries of Faith and Preacher Creeks. 

Similar bodies of related igneous rock are present 

at the head of Sourdough Creek and in the divide 

separating the Faith, Idaho, and Preacher Creek 

drainage areas. (Prindle, 1910, p. 203-209; 

1913, pl. 8; 1913a, pl. 2.) 

Radioactivity studies 

Before the present examination ·of materials 

from the upper Chatanika valley area, only seven placer concentrates, three from Sourdough Creek 

and four from Nome Creek, had been tested for 

radioactivity. Of the seven only a concentrate from 

8 

Nome Creek has more than 0. 01 percent equivalent uranium, and in this the equivalent-uranium 

content is 0. 026 percent. 

The investigations in 1946 were restricted 

to tests of bedrock cropping out in road cuts and 

to tests of concentrates of gravels from streams 

in the immediate vicinity of the highway and sec- ondary roads. The locations of the sites tested are shown on figure 5, and the results are included in table 1. 

Several varieties of schist and qra.nitic rocks were tested. The data of these tests are summarized below. 

Percent equivalent Material u,..._,.,-•l_tlftl tested 

A1 B2 ·as 

Granitic rocks : Station UC l2 1 sample l539L.' 0,005 o.oo4 0,017 

19 ,001 --- --- Graphitic schisti 

Station UC 311 sample l540L .003 ,OOl .003 

32 .003 --- --- " ,003 --- --- 42, aample l;42L .003 .003 c,OOl 44 ,OOl --- --- Schist (other varietiea): 

Station UC 13 ,OOl --- --- 34 .002 ... --- 351 aample l54lL ,002 ,002 --- 43 <.OOl --- --- 'A. Outcfop teece. 

'

18. Teece of unconceacnced CNebed fOck eamplee. 

•c. Teece of bfomofom coaceamcee from cnaebed rock eamplea. 

The relatively hiqher values of equivalent ura- nium in the granitic rocks (station UC 12, sample 

1539L) is probably due to radioactive elements in 

zircon, which was identified in the concentrate; 

A placer concentrate obtained from a dredge on Nome Creek was the only appreciably radioactive placer material from the Chatanika area tested in 1946. Further concentration of the heavy 

minerals by separation in methylene iodide increased the radioactivity only to 0. 012 percent 

equivalent uranium. Minerals of interest in this 

concentrate are relatively abundant topaz and 

cassiterite, and sparse tourmaline and monazite. 

This association suggests that tin-bearing veins 

may occur in the vicinity of the granite at the 

head of Nome Creek. 

Livengood area 

The Livengood area (figs. 1 and 6), as considered in this report, consists of an area about 100 square miles. The town of Livengood, 

the only settlement in the area and the northern 

terminus of the Elliott Highway, is 71 miles 

from Fox on the Steese Highway and 82 miles 

from Fairbanks. The Livengood area is part 

of the Yukon-Tanana upland and is characterized 

by broad, even-topped ridges from which long, 

gently sloping spurs descend to the valley floors. 

The area is drained by Livengood Creek and the 
Cll ;"'<P..,..o 

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!D 
EXPLANATION 

U S Geological .survey 

o- 13 Outcrop test 

lTL 15 Concentrated s_ample I 

w- ()-- test and concentrated samp e 14 Outcrop d pie 

()-16 Outcrop t e stand unconcentrate sam 

b S · "L" in Num er indicate stations prefixed 

table I of text 

Geology modified . . m U S Geological Survey fro . . d 907 

Bulletins 662-D, 872' an 

8 Miles 

. k by Helmuth Wedow, Jr., Base from . · ..., F1eld wor 1946 

Alaska Mop 2' L' engood area, Alaska. 

F1gure . 6 ·-Geologic sketch map of the 1v 

an d J . J · Motzko, August 

10 
Tolovana. River of the Tanana. drainage basin, 

and by tributaries of the South Fork of Hess 

Creek, which in turn is tributary to the Yukon 

River. Dredging· operations of Livengood Placers, 

Inc., on Livengood CrAek and several large scale 

opencut, hydraulic -placer operations on tributaries 

of Livengood Creek and the Tolvana. River are the 

principal mining activities in the area. 

Geology 

The geology of the Livengood area. has been 

discussed in some detail elsewhere. (See Brooks, 

1916; Mertie, 1917; 1937; Overbeck, 1920; and 

Capps, 1940. ) In general, the sedimentary rocks 

of the area have been mapped as two units: 

one, an undifferentiated, chiefly noncalca.reous 

Devonian sequence, which lies to the south of 

Amy Dome; the other, a younger chert and 

silicified limestone sequence of Mississippian age, 

which lies to the north of the dome (fig. 6). 

Mafic rocks of Paleozoic age, thought to be extrusive and intrusive, are closely associated with 

both age groups of the consolidated sediments. 

Tertiary(?) granitoid rocks, predominantly felsic, 

intrude the older rocks in the vicinity of Amy 

Dome. Metamorphic effects and mineralization 

attributed to these later intrusives are clearly 

seen along the divide between Livengood Creek 

and the Tolovana River, and on the flanks of 

Amy Dome. 

Radioactivity studies 

Previous tests of 30 placer concentrates 

from the Livengood area indicated amounts of 

radioactivity of less than 0. 01 percent equivalent 

uranium, except in a. concentrate from Goodluck 

Creek which contains from 0. 031 to 0. 048 percent equivalent uranium. Although a. cursory 

examination of this concentrate before the beginning of the field season of 11:146 failed to reveal 

any mineral to which the radioactivity could be 

ascribed, more detailed study later indicated that 

the radioactivity is due to a. black, pitchy-appearing, 

highly radioactive mineral with a. conchoidal 

fracture. 

Despite the apparently unprom1smg initial 

information, some field work appeared warranted 

to complete coverage of the placers of the area 

in an attempt to obtain other radioactive concentrates, and for testing a few of the sedimentary 

and igneous rocks and the attendant lode deposits. 

The location of these concentrates and outcrop 

tests are shown on figure 6, and the results 

are included in table 1. 

A concentrate donated by a placer operator 

on Ruth Creek (station L 27) was the only placer 

concentrate obtained in 1946 that contains as much 

as 0. 01 percent equivalent uranium. Sedimentary 

·and igneous rocks, for the most part, contain 

less than 0. 001 percent equivalent uranium and 

weathered granite 0. 003 percent equivalent uranium. Results of various radioactivity tests 

made in 1946 on the most radioactive materials 

11 

found in the Livengood area are summarized 

below. 

Percent equivalent 

Material tested uranium 

A1 B2 

Sluice concentrate: 

Station 1 27, sample 1446 --- ---

Panned concentrate: 

Station 1 19, sample 1454 --- --- Black shale: 

Station 1 16a, sample 15531 0.002 0.002 

Weathered granite: 

Station 1 3b, sample 15431 .003 

1 A. Outcrop tests. 2 B. Tests of unconcentrated crushed rock samples. 9C. Tests of bromoform concentrates. 4Test of methylene iodide concentrate. 

.005 

cs 

0.010 

4 .009 

.004 

.006 

.003 

Mineralogical examination of the sluice concentrate listed above indicates that the radioactivity 

is due to uranium- or thorium-bearing zircon, 

although a. few grains of monazite also are present. 

The Livengood area appears to hold little 

promise for significant uraniferous deposits, except, possibly, for the source of the highly 

radioactive mineral in the sample from Goodluck 

Creek. 

Harding Lake-Richardson area 

The Harding Lake-Richardson area (figs. 1 and 7), 

about 50 miles southeast from Fairbanks, is on the 

northeast side of the Tanana River between the lower 

courses of the Salcha. River and Shaw Creek. The 

Richardson Highway crosses the area roughly parallel 

to the course of the Tanana River. Small settlements 

are located at Richardson, and at Birch and Harding 

Lakes. The area shown in figure 7 is about 400 square 

miles, but only a small fraction of this is easily accessible from the highway. Placer gold was first mined 

in this area in the early 1900's, chiefly in the valleys 

of Tenderfoot, Buckeye, and Banner Creeks, and in the 

headwater tributaries of Redmond Creek. Only one 

placer mine, located on claim 13 Below, on Tenderfoot 

Creek, was being worked in 1946. 

Geology 

Pre-Cambrian Birch Creek schist and granite 

rocks of Mesozoic(? )~age form the bedrock of the 

Harding Lake-Richardson area. The Birch Creek schist 

in this area consists chiefly of micaceous and quartzitic 

schists, and intergradations between these two types. 

Minor rock types in the Birch Creek are graphitic 

schist, crystalline limestone, and gneiss. Except for 

the gneiss, the Birch Creek is considered to be derived 

from sedimentary rocks. The gneiss is probably the 

metamorphic equivalent of pre-Cambrian intrusives. 

Quartz veins, in part gold-bearing, are associated 

with the schist. (Prindle, 1913, p. 35, 36, 52, 53, 

140-142, pl. 8; Mertie, 1937, p. 47-59, 210-215, pl. 1; 

Capps, 1940, p. 134, 135, 145, 146, pl.. 3.) 
f-' 

!:\:) 

N 

Q-19 Outcrop test 

ffi--12 Concentrated sample 

t>-to Outcrop test and concentrated sample 

ct-14 Outcrop test and unconcentrated sample 

._, Outcrop test, unconcentrated sample, 

and concentrated sample 

Numbers indicate stations prefixed "R" in 

table I of text 

EXPLANATION 

Granitic intrusives 

Schist 

ll 

z 

<( 

}~ a_ 

Geology modified from U.S. Geological 

Survey Bulletins 525, 872,ond 907 

5 0 25 Miles 

Base modified from U. S. Geological Survey 

Alaska Maps 27, 39, and 49 

Field work by Helmuth Wedow, Jr., 

and J. J. Motzko, August 1946, 

Figure 7. -Geologic sketch map of the Harding Lake-Richardson area, Richardson Highway, Alaska. 
!Radioactivity studies 

Granitic Jocks of Mesozoic(?) age and attendant 

mineralization ~t outcrops of bedrock and in concentrates obtained~rom stream gravels eroded from the 

intrusive mass s and surrounding rocks were tested 

for radioactivit in the Harding Lak.e-Richardson area. 

In addition con entrates were acquired from some of 

the streams fo merly important as producers of gold, as 

this area was not previously represented in the Alaskan 

placer-concentrate file of the Geological Survey. 

The location of the outcrop tests and sites of 

samples are shown on figure 7, and the data obtained 

are included in table 1. A summary of the data on the 

most radioactive materials found in the Harding LakeRichardson area is tabulated below. 

Percent e~uivalent 

Material tested uranium 

A1 B2 cs D4 

Granitic rock, weathered: 

Station R la, sample 1459L 0.006 o.oo4 --- 0.009 

Granitic(?) dike, light-colored, fine-grained, weathered: 

Station R 4a, sample 1460L .005 .002 0.060 .110 

Station R 13b, no sample .005 --- --- ---

Granitic dike, coarse-grained: 

Station R 14a, sample 1556L .005 .oo4 .005 --- Graphitic schists: 

Station R 25b, sample 1557L .002 .001 .005 ---

Stream and bench gravels: 

Station R 23, sample 1464 .001 --- ---- .oo8 

Station R 24, sample 1465 --- --- --- 5 .020 

Station R 25a, sample 1466 <.001 --- --- .009 

1 A. Tests at the outcrop. 2 B. Tests of unconcentrated crushed rock samples. 9 C. Tests of bromoform concentrates from crushed rock samples. 4 0. Tests of panned concentrates from 100-pound samples of unconsolidated material subsequently reconcentrated with bromoform. 5 Methylene iodide used .for final concentration instead of bromoform. 

The radioactivity of the granite may be due to the 

presence of zircon and allanite(?) which were identified 

in a. preliminary study of the concentrates. Scheelite is 

also present. Minerals of interest in the radioactive concentra.tefromBuckeyeCreek(stationR24, sample no. 1465) 

are sheelite, tourmaline, rutile, zircon(?), titanite(?), 

cassiterite(?), and galena.. This association of minerals, 

particularly that of tourmaline, cassiterite(?), and galena, 

suggests the possibility for vein deposits in the drainage 

area. upstream from the site of the concentrate. 

Alaska. Highway belt 

The Alaska Highway belt consists of a long narrow 

area along the highway from Big Delta to the international boundary. It is entirely within the drainage basin 

of the Tanana River. The highway is southwest of the 

river from Big Delta to a point a few miles east of 

Tok Junction; there it crosses the Tanana River and 

follows successively the northeast banks of the Chisana 

River and Scottie Creek to the boundary. The major 

settlements on the highway are Big Delta, Tanacross, 

and Tok Junction; and Northway is just south of the highwaynear the mouth of the NebesnaRiver (figs. 1 and 8). 

Also, a few small native villages are scattered along 

the river banks. 

13 

Geology 

The geology of the area crossed by the 

Alaska Highway (fig. 8) was partly described and 

mapped by Mertie (1937), Moffit (1942), and 

Van Alstine and Black. 1 Some of this previous 

work, however, was revised and extended in 

1946 during the reconnaissance for radioactive 

deposits. 

Granitic intrusives of Mesozoic(?) age constitute the bulk of the bedrock exposed in the 

highway belt. These intrusives apparently cut 

pre-Cambrian or early Paleozoic schists and 

gneisses which are similar to, and in part probaply the equivalent of, the pre-Cambrian Birch 

Creek schist of the Yukon-Tanana upland. 

Radioactivity studies 

The reconnaissance investigation of radioactivity in the Alaska. Highway belt in 1946 was 

devoted chiefly to the granitic rocks of Mesozoic(?) 

age. For convenience in discussion the area is 

divided into two parts: 

1. Localities northwest of Tok Junction 

(stations AH 1-AH 15, fig. 8 and table 1). 

2. Localities southeast of Tok Junction 

(stations AH 1-AH 41, fig. 8 and table 1). 

Localities northwest of Tok Junction. -Data 

on the most radioactive materials from localities ·northwest of Tok Junction are summarized 

below. 

MSterial tested 

Granite, coarse-grained, 

weathered: 

Station AH 15b, sample 1480L 

Stream and bench gravels: 

Station AH la, sample 1469 

Station AH 2, sample 1470 

Station AH 4, sample 1472 

Percent e~uivalent 

uranium 

o.oo4 

,002 

.002 

.002 

so.oo8 

3,014 

4 .011 

4 .008 

1 A. Tests at the outcrop. 2B. Tests oi concentrates panned from 10D-pound samples of gravel. 

Fi~al concentration made with methylene iodide. 4 Final concentration made with bromoform. 

Preliminary study of the concentrates indicates 

the presence of minor amounts of zircon, a 

mineral which may be radioactive because it can 

contain uranium and thorium. All the gravels 

listed in the above tabulation are from streams 

draining areas 'underlain by granitic rocks. 

1Van Alstine, R. E., and Black, R. F., 1944, Geology of the 

Alaska military highway from the international boundary to Big Delta, 

Alaska. [Unpublished rept., 1944. Manuscript and maps in the files 

of the U.S. Geol. Survey Alaskan Geology Branch.J 
f-' 

>P> 

~ 

~ ~ 

EXPLANATION 

o-31 Outcrop test 

()- 41 Outcrop test and unconcentrated 

sample 

.-36 Outcrop test, unconcentrated sample 

and concentrated sample 

$- 33 Concentrated sample 

()-- 29 Outcrop test and concentrated sample 

Numbers indicate stations prefixed 

"AH" in table I of text 
......, 

01 EXPLANATION 

G ~ 

0 N -<'-

Granitic intrusive ~ u o 

rocks :::!: 2 2 "// " r-0 0 "// -~- ~a::~ 

Schists and gneisses (t 0 Cf 

tL a:: 

Schist 

Gneiss ~ with granitic 

intrusive rocks 

IJJO:: IJJ (.!)Q. 3: <( 0 

z ..:J 

3: 

0 

z 

~ 

z 

:::> 

Geology in part from reconnaissance 

in 1946, and in part modified from 

U. S. Geological Survey Bulletins 

872 and 926-B; unconsolidated 

deposits excludeq 

1:1 

~ 'b 

~ ~ 

10 0 30 Miles 

Bose from U. S. Geological Survey .Alaska Mops 49 and 52 

FJeld work by 

and J. J. Motzko, August 1946 

Figure 8. -Geologic sketch map of the Alaska Highway belt, upper Tanana valley, Alaska. 

N 
Localities southeast of Tok Junction. -Data. on 

the most radioactive materials from localities southeast of Tok Junction are summarized below. 

Percent equivalent 

Material tested urR.r -ium 

Al B2 cs D4 

Granite, coarse-grained, 

weathered: 

Station AH 40, sample 1490L o.oo4 

and sample 1547L. 

0.001 0.013 0.07 

Station AH 17a, sample 1481L .005 --- --- .o6 

Station AH 37, sample 1489L .oo4 --- --- s.02 

Station AH 26, sample 1483L .003 --- --- .02 

Station AH 36b, samples 1488L .oo4 .001 .023 .01 

and 1546L. 

Felsitic(?) dike, weathered: 

Station AH 3lb, sample 1662L .003 .003 .010 --- 1 A. Tests at the outcrop. 

4 

4 

7 

5 

0 

'

2 8. Tests of unconcentrated crushed rock samples. 

ac. Tests of bromoform concentrates from• crushed rock samples. 4 0. Tests of panned concentrates from lOO·pound samples of uncon· 

solidated material subsequently reconcentrated with methylene iodide. 

~Bromoform used for final concentration instead of methylene iodide 

Subsequently, samples 1481L and 1490L in the above 

tabulation were concentrated further by removing a 

magnetic fraction with a hand magnet. The equivalenturanium content in the resultant nonmagnetic fractions 

of these two samples was then determined to be 0. 65 

and 0. 89 percent, respectively. 

Preliminary mineralogical studies of the concentrates from the granitic rocks show the presence of zircon in all samples from the five 

localities, usually in large amounts. Although it 

is presumed that the concentration of the zircon 

is to a large extent responsible for the increased 

radioactivity of the concentrates, other Alaskan 

studies (Moxham and West, 1953, p. 7; White. and 

Killeen, 1953, p. 3) have shown that the radioactivity of pure zircon fractions of concentrates 

from granitic rocks was found to range, only from 

0. 1 to 0. 15 percent equivalent uranium. Hence, 

zircon alone probably cannot account for the total 

radioactivity in samples 1481L and 1490L mentioned above. Allanite, another mineral which 

may contain uranium and thorium, has been 

identified also in these two concentrates (samples 

1481L and 1490L) as well as in a third (sample 

1483L). Although it is likely that the zircon and 

a.llanite account for the bulk of the radioactivity 

in the samples, traces of other, as yet unidentified, highly radioactive minerals may also be 

present. Other heavy minerals of interest identified 

in the concentrates from the granitic rocks are 

epidote, tourmaline, and axinite(?). 

The refractory nature of the chief radioactive 

minerals in granitic rocks in the Alaska Highway belt 

indicates that these rocks should not be considered as 

a possible commercial source of uranium or thorium. 

If additional miner.alogic study of the samples indicates 

the presence of radioactive oxide minerals, the problem 

then arises as to whether such radioactive oxide minerals occur as disseminated accessory minerals in 

the granitic rocks or are limited to a particular facies 

of the granite, or occur in vein systems cutting the 

granitic rocks. 

16 

Highway area between Slana and Tok Junction 

The highway area between Slana and Tok 

Junction (figs. 1 and 9) lies across the divide between 

the Copp~r River and Tanana River basins. This new 

road, about 70 miles long and known informally as 

the "Tok cutoff,'' connects the Alaska Highway with 

the old Nabesna road by way of Mentasta Pass (altitude 

about 2, 300 feet). It was originally constructed by 

the Army Engineers of the Alaska Department, and 

more recently, has beeri improved and maintained by 

the Alaska Road Commission. This road has opened 

up much country formerly accessible only by pack train. 

The area is drained chiefly by the Tok River, a northflowing tributary of the Tanana River, and by the 

Slana River, a south-flowing tributary of the Copper 

River. 

G.eology 

The geology of the area between Slana and 'l'o.k: 

Junction has been described by Moffit (1938) in con~ 

junction with surveys in the Copper River basin. The 

bedroqk of the Slana-Tok district is a part of the core 

of the Alaska Range which here has a northwesterly 

trend. Moffit (1938, p. 1) states: 

"The rocks of the district are prevailingly sedimentary but include tuff beds and lava flows and many 

masses of intruded granitic rocks, most of which are diorite and related types rather than granite. Some of 

these rocks are highly metamorphic. Others are greatly 

folded yet not notably altered. The structure is complex and not clearly understood. The rocks range in 

age from pre-Cambrian or early Paleozoic to late 

Mesozoic. In places they are concealed by Recent unconsolidated waterlaid and glacial deposits." 

The distribution and age of the different rock types 

are shown on the geologic sketch map of the area 

(fig. 9). 

Radioactivity studies 

Tests for radioactivity in the area along the Slana.-

Tok highway were made principally on concentrates 

from gravels in tributaries of the Slana and TokRivers. 

The locations at which the concentrates were taken, 

as well as the few other tests on a lode deposit, are 

shown on figure 9. The data are included in table 1. 

The equivalent- uranium values for 20 concentrates from gravels in the Slana-Tok Junction highway 

area range from <0. 001 to 0. 003 percent, and average 

0.001 percent. A silver prospect (Moffit, 1938, p. 46,47) 

on Silver Creek, a small tributary of Ahtell Creek 

near Slana, was also tested for radioactivity. The 

mineralization consists of silver-bearing quartz veins 

in a fault zone. The country rock is chiefly mediumgrained gray diorite and a dark basaltic-appearing 

rock that is probably igneous. The metallic minerals 

reported in the lode are sphalerite, pyrite, galena, and 

tetrahedrite. The silver is probably associated chiefly 

with the tetrahedrite and galena. Tests on materials 

from the Silver Creek lode indicate that the radioactivity is less than 0. 001 percent equivalent uranium. 

An unconcentrated crushed sample of the country rock 
016 

Outcrop test 

E9 18 

Concentrated sample 

Outcrop test and co t) ncentroted 6 

• 12 

sample 

TO NABESNA 

IO Miles 

I I 

Alluvium 

I 

l ffi>-

t-0:: 

<(<( 

:::>Z 

0 

<(...., l

uR 

.... (/) 

w=> o::O 

uw 

}

o::6 

WN 

a..o 

a..w ::::>...J 

~ 

Undifferentiated ~ ::3 schist with rock chiefly o 8 

f\"~~~ )u ~ some 1 wo:: ...J 

rocks and b .. vo conic ...JO~ rocks of a.stc Intrusive ~ a: vortous ages 0::: w ~ 

~ c.~ 

U ndi ffe rentioted vole · and basic intr . ante rocks 

various ages ustve rocks of 

Geology . 

S 

modtfied f 

urvey B . rom u.S G solid ullettn 904· · · eologicol ated deposits e' mltnor uncon- xc uded 

Base from U · S. Geolo · Alaska Map g~c;l Survey 

Figure 9. -Ge Field wor ologic sketch m ap of Motz k by Helmuth Wedo the high ko, August-Sept w, Jr., ond J J 

way area bet . ember 1946 .. 

ween Slana and 17 Tok J uncti on, Alaska. 
near the lode (station TC 12c), however, shows 

0. 005 percent equivaient uranium, but the bromoform 

concentrate from this sample has only 0. 001 percent 

equivalent uranium. 

Donnelly Dome-Paxson area 

The Donnelly Dome- Paxson area, as considered 

in this report, is a narrow strip along the Richardson 

Highway about 70 miles in length between Donnelly 

Dome on the north and Paxson on the south (figs. 1 and 

10). It is drained by the Delta River and its tributaries 

except at the most so.utherly end where it lies in the 

watershed of the Gulkana River, a tributary of the 

Copper River. In 1946, roadhouses were located at 

Rapids and Paxson. 

Geology 

The geology of the Donnelly Dome-Paxson area 

has been described in reports of broader regional 

scope '(Moffit, 1912, 1942). The northern part of the 

area is underlain by schists and gneisses of prePaleozoic or early Paleozoic age, which in part may 

be equivalentto the pre-Cambrian Birch Creek schist 

of the Yukon-Tanana region to the north. The southern 

part of the area, although covered to a considerable 

degree by unconsolidated glacial and glacio-fluviatile 

deposits, is underlain by Carboniferous sedimentary 

rocks and lavas. Granitic rocks, cortsidered to be 

pre-Tertiary in age, intrude the schists in the northeast corner of the area. Jurassic(?) intrusives of 

dioritic affinities are associated with the Carboniferous 

:rocks "in the southern part of the area. In the vicinity 

of Donnelly Dome and Jarvis Creek, Tertiary coalbearing sediments unconformably overlie portions of 

the metamorphic basement, and are covered with a 

thin veneer of glacial debris. 

Prospecting for placer gold in the Donnelly DomePaxson area has been carried on intermittently since 

about 1900. The most promising streams are Jarvis, 

Ober, and Macomber Creeks, although gravels of 

several other streams also contain placer gold. Mining 

activity in 1946 was limited to prospecting of claims 

on Ober Creek by Charles DeWitt, and to operations by 

the Yukon Corporation on the east bank of the Delta 

River about a quarter of a mile downstream from the 

mouth of Phelan Creek (fig. 10). 

Radioactivity studies 

As only a few days remained toward the close of 

the 1946 field season for the investigation of the 

Donnelly Dome-Paxson area, the work in that area 

consisted only of panning concentrates from various 

stream gravels. No concentrates had been available 

for study before the 1946 field season. The stations 

at which the concentrates were obtained are plotted on 

figure 10, and the data are included in table 1. 

The equivalent-uranium content of 12 bromoform 

concentrates (stations RH 1-12) from stream gravels 

south of Donnelly (fig. 10) ranges from <0. 001 to 

0. 004 percent and averages about 0. 002 percent. 

The equivalent-uranium content of four concentrates 

(stations RH 13-15) obtained from prospecting operations 

18 

on Ober Creek ranges from 0.003 to 0. 011 percent and 

averages about 0.006 percent. The radioactivity is appar-

. ently due to the presence of small quantities of monazite 

in the concentrates. Tourmaline, zircon, fluorite, and 

epidote also occur in the Ober Creek concentrates. 

CONCLUSION 

Some granitic rocks and placer concentrates 

tested in areas adjacent to highways in the Tanana and 

upper Copper River valleys are moderately radioactive 

and thus may be of significance in the search for commercial deposits of radioactive elements in these areas 

Black shale, carbonaceous or graphitic schist, and 

mineralized vein deposits tested in this reconnaissance 

exhibited only traces of radioactive material. 

The most significant results for the material tested 

are summarized below. 

~e of percent equivalent 

uranium 

Type of material and area Outcrop tests Concentrated 

and unconcen- samples r .. ra ted samples 

Granitic rocks: 

Fairbanks district-----

Upper Chatanika valley 

area-----------------

Livengood area--~-----­

Rarding Lake-Richardson 

area~----------------

Alaska Highway belt----

Highway area between 

Slana and Tok 

Junction-------------

Donnelly Dome-Paxson 

area-~---------------

Mafic rocks : 

FairbSnks district-----

Upper Cha tanika valley 

area-----------------

Livengood area--------- Harding LakeRichardson area------ Alaska Highway belt----

Highway area between 

Slana and Tok 

Junction-------------

Donnelly Dome-Paxson 

area-----------------

Mineralized veins and 

vein materials: 

lc:O.OOl-0.003 0,002-0.004 

,001- ,005 .017 

<,,001- .005 .003 

.002- .oo6 .005- .ll 

,001- ,005 .oo4- .074 

.001 

<,001- .001 

<,001 

.002- .003 

.001- .003 .oo4 

<·,00~- .005 <,001 

Fairbanks district----- <,001- .005 <,001- .013 

Upper Cha tanika valley 

area-----------------

Livengood area--------- <,001 

Harding LakeRichardson area------ .003 

Alaska Highway belt----

Highway area between 

Slana and Tok 

Junction------------- <,001- .001 

Donnelly Dome-Paxson 

area-----------------

Schist, quartzitic and 

micaceous varieties: 

Fairbanks district----- <,001- .002 

Upper Chatanika valley 

area----------------- <.001- .003 

Livengood area--------- Harding LakeRichardson area------ .001- .002 

Alaska Highway belt---- <,001- .002 

<.001 

<,001 

,003 
Base from U. S. Geological Survey 

Alaska Mop 49 

' 5 

VALDEZ 

EXPLANATION 

Granite 

Dioritlc(? l intrusives 

Amygdaloldal lava 

Metamorphosed sediments and 

associated Intrusive rocks 

Schists and gneisses 

) 

) 

Geology generalized from U. S. Geological 

Survey Bulletins 498 and 926-B, 

unconsolidated deposits excluded 

erl3 

Concentrated sample; number indicates 

station prefixed "RH" in table I 

of text 

N 

0 

>-

0:: 

<t 

;:: 

0:: 

LLI 

'I 

LLI 

0:: 

~ 

(/) 

;:) 

0 

0:: 

LLI 

LL. 

z 

0 

CD 

0:: 

<t 

u 

15 Miles 

Field work by J. J. Motzko and 

Helmuth Wedow Jr. September 1946 

Figure 10. -Geologic sketch map of the Donnelly Dome-Paxson area, Richardson Highway, Alaska. 

19 
~e of percent equivalent ura.n·.um 

Type of material and area Outcrop tests C t t d . . and unconcen- oncen ra e 

Schist, quartzitic and 

micaceous varieties 

Continued: 

Highway area between 

Slana and Tok 

Junction------------

Donnelly Dome-Paxson 

area----------------· 

Schist, graphitic: 

Fairbanks district----· 

Upper Cha tanika valley 

area----------------

Livengood area-------- Harding LakeRichardson area------ Alaska Highway'belt----

Highway area between 

Slana and Tok 

Junction------------

Donnelly Dome-Paxson 

area-----------------

Black shale.: 

Fairbanks district----· 

Upper Chatanika valley 

area----------------

Livengood area-------- Harding LakeRichardson area-----

Alaska Highway belt----

Highway area between 

Slana and Tok 

Junction------------

Donnelly Dome-Paxson 

area----------------

Stream and bench gravels, 

and slope wash: 

Fairbanks district----

Upper Cha tanika valley 

area----------------· 

Livengood area--------· Harding LakeRichardson area-----

Alaska Highway belt---

Highway area between 

Slana and Tok 

Junction------------

Donnelly Dome-Paxson 

area----------------

trated samples samples 

0.002 o.oo4 

0.001- .004 .000 

.001- .002 .005 

<.001- .002 .oo6 

<.001 ~0.001- .003 

.001- .Oil 

<.001- .003 <.001- .o66 

<.001- .001 <.001- .012 

<.001- .001 <.001- .01 

<.001- .001 .001- .02 

.001- .002 <.001- .014 

<.001 <.001- .003 

<.om_ .m1 

LITERATURE CITED 

Bastin, E. S., and Hill, J. M., 1917, Economic 

geology of Gilpin County and adjacent parts of Clear 

Creek and Boulder counties, Colorado: U. S. Geol. 

Survey Prof. Paper 94. 

Brooks, A. H. , 1916, Preliminary report on the 

Tolovana. district [Alaska.] : U. S. Geol. Survey 

Bull. 642-G, p. 201-209. 

20 

Capps, S. R., 1940, Geology of the Alaska Railroad 

region: U. S. Geol. Survey Bull. 907. · 

Chapin, Theodore, 1914, Lode mining near Fairbanks 

[Alaska]: U. S. Geol Survey Bull. 592-J, 

p. 321-355. 

Ellsworth, C. E., 1910, Placer mining in the YukonTanana region [Alaska.]: U. S. Geol. Survey Bull. 

442-F, p. 230-245. 

Hill, J. M., 1933, Lode deposits of the Fairbanks 

district, Alaska: U. S. Geol. Survey Bull. 849-B, 

p. 29-163. 

Kidd, D. F. , and Haycock, M. H. , 1935, Mineralogy 

of the ores of Great Bear Lake: Geol. Soc. America 

Bull., v. 46, no. 6, p. 879-960. 

Mertie, J. B., Jr., 1917, The gold placers of the 

Tolovana. district [Alaska] : U. S. Geol. Survey 

Bull. 662-D, p. 221-277. 

-;-;--;::;---::::~1937, The Yukon-Tanana. region, Alaska: 

U. S. Geol. Survey Bull. 872. 

Moffit, F. H., 1912, Headwater regions of the Gulkana. 

and Susitna. Rivers, Alaska, with accounts of the 

Valdez Creek and Chistochina placer districts: 

U. S. Geol. Survey Bull. 498. 

-..,.,..___, __ 1938, Geology of the Slana.-Tok district, 

Alaska: U. S. Geol. Survey Bull. 904. 

1942, Geology of the Gersne River 

-d ....i,...s~tr __ i,...c~t,- Alaska: . U. S. Geol. Survey Bull. 926-B, 

p. 107-160. 

Moxham, R. M., and West, W. S., 1953, Radioactivity 

investigations in the Serpentine-Kougarok area, 

Seward Peninsula, Alaska, 1946: U. S. Geol. Survey 

Circ. 265. 

Overbeck, R. M. , 1920, Placer mining in the Tolovana. 

district [Alaska]: U. S. Geol. Survey Bull. 712-F, 

p. 177-184. 

Prindle, L. M. , 1905, The gold placers of the Fortymile, Birch Creek, and Fairbanks regions, Alaska: 

U. S. Geol. Survey Bull. 251. 

-----,.-~1908, The Fairbanks and Rampart quadrangle, Yukon-Tanana. region, Alaska: U. S. Geol. 

Survey Bull. 337. 

---=----1910, Sketch of the geology of the northeastern part of the Fairbanks quadrangle [Alaska]: 

U. S. Geol. Survey Bull. 442-F, p. 203-209. 

1910a., Auriferous quartz veins in the 

-=F,_a..,...ir...,.b_a_n.,....ks district [Alaska.]: U. S. Geol. Survey 

Bull. 442-F, p. 210-229. 

-=-..,.......,._.,..1913, A geologic reconnaissance of the 

Fairbanks quadrangle, Alaska, with a. detailed description of the Fairbanks district, by L. M. Prindle 

and F. J. Katz, and an account of lode mining near 

Fairbanks, by P. S. Smith: U. S. Geol. Survey 

Bull. 525. 

-=-:---;--1913a, A geologic reconnaissance of the 

Circle quadrangle, Alaska: U. S. Geol. Survey 

Bull. 538. 

White, M. G., and Killeen, P. L., 1953, Reconnaissance for radioactive deposits in the lower 

Yukon-Kuskokwim Highlands .region, Alaska, 1947: 

U. S. Geol. Survey Circ. 255. 
1:\:) 

,...._. 

Table 1.--Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River valleys, Alaska 

[Abbreviations in subheadings under "Percent equivalent uranium" indicate the following: OT, outcrop test; UCS, unconcentrated crushed sample; BC-CS, bromoform concentrate from crushed sample; BC-PC, panned 

concentrate from 50- to 100-pound samples of gravel or disintegrated rock material subsequently reconcentrated with bromoform; also includes sluice concentrates obtained from placer-mine operators.] 

Sample Percent equivalent uranium ConcenDescription and location Test file tration station 

PD 1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

no. 

1401L 

1527L 

1537L 

OT I 

0.001 

<.0011 

.001 

<.00111 

.001 

• 001 

.001 

.001 

<.001 

.002! 

.001 

.001 

.003 

.002 

.001 

.001 

.001 

.001 

.000 

.001 

.001 

.001 

<.001 

.001 

.001 

.001 

.001 

.001 

.001 

.001 

.001 

.002 

.001 

.001 

ucs 

0.003 

.002 

See footnotes at the end of the table. 

l BC-CS I 

0.004 

1 .004 

BC-PC ratio 

Pedro Dome area (fig. 3) 

0.002 

Weathered quartz diorite; on road to summit of Pedro Dome. 

Weathered quartz diorite; 200 feet south of PD 1. 

Weathered quartz diorite; 300 feet south of PU 1. 

Weathered quartz diorite; 500 feet south of PD 1. 

Weathered quartz diorite; 700 feet south of PD 1. 

Weathered quartz diorite; 800 feet south of PD 1 • 570:11Weathered quartz diorite; 900 feet south of PD 1. 

Weathered quartz diorite; 1,000 feet south of PD 1. 

Weathered quartz diorite; 1,100 feet south of PD 1. 

Weathered quartz diorite; 1,200 feet south of PD 1. 

Weathered quartz diorite; 1,300 feet south of PD 1. 

Quartz diorite talus; on road to summit of Pedro Dome, 1,400 feet 

south of PD 1. 

4:11 Do. 

Do. 

Quartzitic schist; in stripped area about 0.6 mile northeast of 

Pedro Dome. 

Do. 

Weathered quartz vein; in series of old prospect pits about 1 mile 

northeast of Pedro Dome. 

Do. 

Weathered schist; same locality as PD 17. 

Weathered quartz vein; same locality as PD 17. 

Weathered quartzitic schist; same locality as PD 15. 

Do. 

Weathered micaceous schist; same locality as PD 15. 

Weathered phyllite; same locality as PD 15. 

Weathered schist, same locality as PD 15. 

Do .. Weathered schist, same locality as PD 17. 

Do. 

Do. 

Weathered quartz vein and schist; in old prospect pits west of 

road about 1.5 miles northeast of Pedro Dome. 

Do. 

4:11Thin bed of graphitic schist; in stripped area along east side of 

road about 1.5 miles northeast of Pedro Dome. 

Do. 

Fractured quartz vein; same locality as PD 32. 
M 

M 

-

Test 

station 

PD 35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

Sample 

file 

no. 

1538L 

1408 

1409L 

1410L 

1411 

lltl2L 

1536AL 

1536BL 

1413 

~ u -- -o-· .. " ... && -- --- ~ - ----- Cl -., ----

Concen- Percent equivalent uranium tration Description and location 

OT l ucs l BC-CS 1 BC-PC ratio 

Pedro Dome area--Continued 

0.002 

<.001 

<.001 

. . 001 

<.001 

<.001 

.001 

.001 

.001 

<.001 

<.001 

.001 

.001 

.OOl 

<.001 

• 001 

• 001 

.001 

"'.001 

.001 

.001 

• 001 

.001 

• 001 

• 001 

.001 

• 001 

.001 

.001 

.001 

<.001 

0.002 

.001 

.003 

0.013 

.001 :1 .001 

. oo; 

.00~ 

.003 

.001 

.00~ 

.003 

Graphitic schist; same locality as PD 32. 

Iron-stained quartz vein; Boyle's prospect near junction of Fairbanks Creek road and Steese Highway. 

Do • 

Disintegrated rock on mine dump; same locality as PD 36. 

Weathered schist; in road cut on Steese Highway in Skoogy Gulch. 

Do. 

336:liVein material on mine dump; Eagan scheelite mine on Twin Creek. 

Iron-stained schist; in old prospect pit along Steese Highway near 

mouth of Twin Creek. 

Weathered quartz and schist on mine dump; at old prospect shaft on ridge between Fox Creek and Seattle Pup about 0.85 mile east of 

road. 

Do. 

Do. 

Do. 

l,l50:11Slope wash(?}; in bull-dozer trench 0.6 mile east of station PD 43 • Do. 

Weathered quartz vein and schist on mine dump; at old prospect 

shaft near station PD 46 • 

Do. 

Slope wash; in trench about 300 feet east of station PD 46-• 

Do. 

Weathered quartz vein and schist on mine dump; at old prospect 

shafts 0.7 mile east of station PD 43. 

1,200:11 Do. 

Do. 

Same as PD 53, but 0.3 mile farther east • 

1,530:11 Do. 

Same as PD 53, but 0.45 mile farther east • Do •. 

Do. 

770:1 Angular gravel from test pit; Seattle Pup • 270:1 Weathered rock on mine dump; at prospect shaft on divide between 

Seattle Pup and Moose Creek. 

10:1 Sulphide-enriched limestone; at station PD 62. 

2:1 Do. 

700:1 Angular gravel from test pit; on south tributary of Last Chance 

Creek. 

Disintegrated rock on mine dump; on ridge between Engineer and 

Steele Creeks. 

Do. 
N 

c.:> 

66 

67 

68 

69 

70-

71 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

82 

83 

84 

85 

86 

87 

88 

89 

90 

91 

92 

93 

94 

95 

96 

97 

98 

99 

100 

101 

102 

103 

104 

105 

106 

107 

loB 

109 

110 

111 

1397L 

1396 

1400 

1402 

1403 

1404 

1405 

1406 

1407 

1391 

1392 

1393 

1394 

1395 

1398 

1399 

1414 

1415 

1416 

.001 

.001 

<.001 

.001 

• 001 

.0021 

.001 

<.001 

<.001 

• 001 

<,001 

• 001 

.001 

<.001 

.001 

<.001 

.001 

.001 

<.001 

.001 

<.001 

<.001 

<.001 

·.001 

.002 

• 002 

.002i 

• 001 

.001 

• 001 

.001 

<,001 

• 001 

.002. 

.00 

.001 

<.001 

<.001 

.001 

.003 

<,001 

.0011 

.002 

<,001 

.001 

.001 

See footnotes at the end of the table. 

Do. 

Do. 

Do. 

Disintegrated rock on mine dump; on ridge between Engineer and 

Steele Creeks. 

Do • .oo61 1,410:11 Do. 

<.001 15,620:1 Slope wash rrom test pit; on ridge between Engineer and Steele 

.003 

.003 

.004 

<.001 

.005 

• 004 

.001 

.003 

.003 

.004 

.005 

.002 

.066 

.003 

<.001 

.004 

.003 

Creeks. 

Do. 

Tungsten vein in drirt; Gilmore Dome. 

Bedrock in same drirt; Gilmore Dome • Tungsten vein in second drirt; Gilmore Dome. 

Tungsten vein 500 reet rrom mouth or third drirt; Gilmore Dome . Rock on dump or third drirt; Gilmore Dome. 

Marie rock in dump or shart at summit; Gilmore Dome. 

Tungsten vein in opencut near summit; Gilmore Dome. 

Do. 

Do. 

Marie rock in dump or shart at summit; Gilmore Dome. 

Do. 

Tungsten vein in rirst drirt; Gilmore Dome. 

Bedrock in rirst drirt; Gilmore Dome. 

Tungsten vein in second drirt; Gilmore Dome. 

Bedrock in second drirt; Gilmore Dome. 

Marie rock in dump or shart at summit; Gilmore Dome. 

2,940:11Angular gravel rrom test pit; north tributary or Isabella Creek. 

Do • 

550:11 Stream gravel rrom test pits; Gilmore Creek. 

1,030:1 Angula~~avel rrom test pit; north tributary or Victoria Creek • 

Do • Do. 

17,450:11Stream gravel (slope wash?) rrom several closely spaced gullies; 

Monte Cristo Creek. 

Do • 3~340:1 Stream gravel rrom test pit; east fork or Tom Creek. 

1,860:1 Stream gravel rrom test pit; west rork or Fish Creek • 460:1 Stream gravel rrom test pit; Deadwood Creek. 

5,790:1 Angular gravel rrom test pit; east headwater tributary or Engineer 

Creek. 

1,740:1 Angular gravel rrom test pit; west headwater tributary or Moose 

Creek. 

4,58o:l Angular gravel rrom test pit; middle rork or northwest tributary 

or Columbia Creek •. 240:1 Angular gravel rrom test pit; Columbia Creek. 

1,470:1 Angular gravel rrom test pit; Engineer Creek. 

5,030:1 Stream gravel rrom test pit; Rex Creek. 

2,600:1 Angular .gravel rrom test pit; middle rork or Steele Creek. 

470: 1 Stream gravel; Willow Creek. 

1,240:1 Angular gravel in placer cut; Wolr Creek. 

1,470:1 Stream gravel; Chatham Creek. 
M 

~ 

Taoie i.~ua~a on rau~oac~~v~~Y ~es~s ~n areas auJacen~ ~o lllgnwa vs ~n ~ne Tanana ana upper vOPPt:r n.Lvtn· v<:Uiey..,, .H.itLt~KtL-vUnLlnueu 

Test 

station 

PD 112 

113 

114 

115 

116 

117 

ED 1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

Sample 

file 

no. 

1417 

1418 

1419 

1420 

1421 

1422 

1530L 

1531L 

1532L 

1423 

1533L 

1424 

1425 

1534L 

1535L 

1426L 

1427 

1428 

1523L 

1524L 

I Concen- I Percent equivalent uranium tration Description and location 

OT I ucs I BC-CS I BC-PC ratio 

<0.001 

.001 

• 001 

<.001 

.001 

<.001 

0.001 

. 002 

.001 

.001 

.002 

• 002 

.002 

.001 

.002 

.001 

.003 

. 001 

.004 

.004 

.001 

.004 

. 001 

.001 

.002 

.002 

• 003 

. 002 

.003 

.001 

• 002 

.002 

• 001 

---

---

---

-~-

---

---

<0.001 

.002 

.002 

.002 

.003 

<.001 

• 0051 

.001! 

---

---

---

---

---

---

<0.001 

• 002 

. 004 

.005 

<.001 

<.001 

.003 

Pedro Dome area--Continued 

<0.001 120:1 Angular gravel; Bellows Creek. . 001 330:1 Angular gravel; Solo Creek • 

.001 540:1 Angular gravel; south tributary of Fairbanks Creek • <.001 1,770:1 Angular gravel from cut in stream bank; west tributary of Fox 

Creek. 

.005 1,510:1 Angular gravel from test pit; Big Eldorado Creek. 

<.001 830:1 Angular gravel from test pit; northwest tributary of Big Eldorado 

Creek. ---

Ester Dome area (fig. 4) 

.004 

.0071 

.oo4! 

.005 

. 004 

.004 

19:1 Massive quartz vein in drift; Michley mine on Sheep Creek • -- Shear zone in schist; Michl~y mine on Sheep Creek. 

48:1 Mineralized part of quartz vein; Michley mine on Sheep Creek • 

390:1 Stream gravel; Sheep Creek below Michley mine • 28:1 Rock material from mine dump; Bondholder mine. 

Rock material on mine dump; Mohawk(?) mine • 

400:l1Stream gravel; St. Patrick Creek. 

810:1 Stream gravel from test pit; Ready Bullion Creek. 

Rock material on mine dump; Farmer(?) mine at head of Ready Bullion 

Creek. 

Do. 

19:11 Do. 24:1 Do • 1,080:1 Rock material on mine dump; Clipper mine on Eva Creek. 

Do. 

Rock material on mine dump; drift below Clipper mine on Eva Creek. 

Do • 

l,lOO:liStream gravel from test pit; Moose Gulch • 

1,;40:1 Stream ~~avel from test pit; Eva Creek below Clipper mine. 

Mine dump; at prospect shaft on trail to summit of Ester Dome • Do • Weathered schist; trench near station ED 20. 

Do. 

Weathered antimony ore; trench near station ED 20 • Mine dump; at inclined shaft about 0.2 mile southwest of summit of 

Ester Dome. 

Do • Selected pieces of sulphide ore; same location as station ED 25. 

(?) !Vein material(?); Michley mine • 

8:1 Vein material(?); Hudson mine. 
!:\:) 

()1 

uc 

30 

31 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

1429 

1430 

1431 

1432 

1539L 

1433 

1434 

1435 

1436 

1437 

1438 

1540L 

1541L 

0.001 

.0011 

<.0011 

:gg~i .001~ 

• 001 

.001 

• 001 

.001 

.001 

.005 

• 001 

.001 

.001 

.001 

.001 

.001 

.OOli 

<.001! 

.001! 

<.001! 

.001 

.001 

.001 

.'0011 

• 001 

.001 

.001 

. 001 

.003 

• 003 

• 003 

.002 

. 002 

.002 

<.001 

See footnotes at the end of the table. 

0.004 

.001 

.002 

Vein material(?); Sanrord prospects. 

Vein material(?); Little Eva mine. 

Steese Highway belt in upper Chatanita valley (rig. 5) 

0.017 

.003 

<0.001 

<.001 

.001 

<.0011 

<.001 

.oo:;: 

<.OOli 

<.001 

. 001 

.002 

. 00~ 

(?) Stream gravel; McManus Creek about halfWay between Montana and 

Idaho Craeks. 

100: ~ Do. 

90:1 

130:1 

267:1 

120-:1 

Do. 

Do. 

Do. 

Stream gravel rrom prospect pit; Idaho Creek about 250 reet above 

highway bridge. 

Do • Do. 

Do • Stream gravel rrom prospect pit; Idaho Creek about 3,000 feet 

above highway bridge. 

Do. 

Porphyritic biotite granite boulders and pebbles; same location 

as station UC 10. 

Schist boulders; same location as station UC 10 • Stream gravel; Montana Creek about 25 feet above highway bridge. 

Do. 

Stream gravel; Montana Creek about 0.5 mile above highway bridge. 

160:11 Do. 

Stream gravel; North Fork of Twelvemile Creek (Circle district). 

Weathered igneous cobbles (granite?); North Fork of Twelvemile 

Creek (Circle district). 

Stream gravel; same location as station UC 19. 

45:11 Do. 

90:1 Stream gravel; Twelvemile Creelc (Circle district) above mouth of 

North Fork • llO:liBench gravel; Faith Creek, trench in northwest bank about 0.5 mile 

above mouth. 

Bench gravel; trench abqut 400 feet northeast of station UC 23. 

280:11Bench gravel; trench about 100 feet east of station UC 24. 

Do. 

Bench gravel; trench about 200 feet northeast of station UC 25 • Stream gravel; Smith Creek about 0.25 mile above mouth. 

380:11 Do • 

Bench gravel; same location as station UC 28 • 133:11Weathered gray-black micaceous schist (fault gouge?) Steese Highway, Mile 70.2. 

Do • Do . Weathered quartz mica schist; Steese Highway, Mile 70.2. 

Do . Do. 

Stream gravel; Faith Creek about 5 miles above mouth. 
C\:) 

m 

Table 1.--Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River valleys, Alaska--Continued 

Sample Test 

station file 

no. 

uc 38 ----

39 1440 

40 1441 

41 1442 

42 1542L 

43 ---- 44 ---- 45 1443 

L lal 1555L 

lb 

2 

3a 

3bl 1543L 

4 

5 

6 

7 

8 

9a 

9b 

10 

11 1447 

12 1448 

13 ---

14 1449 

15 I 1450 

16a 1553L 

16b 

16c 

17a 

17b 

18a 1452 

18b 1453 

19 1454 

20 1455 

OT 

Concen- Percent equivalent uranium tration Description and location 

---

0.001 

.001 

.001 

.003 

<.001 

. 001 

---

0.001 

<.001 

<.001 

.001 

.003 

.001 

<.001 

<.001 

<.001 

<.001 

<.001 

<.001 

.001 

.001 

.001 

<,001 

.002 

.001 

.001 

.001 

.001 

I ucs 

---

---

---

---

0.004 

---

---

---

0.0051 

.002 

I BC-CS I BC-PC ratio 

Steese Highway belt in upper Chatanita valley--Continued 

---

---. 

---

--- <0.001 

---

---

---

'<0.001 

.0031 

.006 

0.001 (?) About ~ cubic foot sluice concentrates after removal of gold; 

Deep Creek; workings of Deep Creek Mining Co. 

.001 95:1 Stream gravel; Cripple Creek about 50 feet above highway bridge. 

.002 350:1 Bench gravel; Flat Creek. . 002 190:1 Stream gravel; Belle Creek about 100 feet above highway bridge . 

--- (?) Weathered graphitic schist; Steese Highway, Mile 64.3. 

--- --- Weathered gray schist; Steese Highway, Mile 64.3. 

--- --- Graphitic schist; Steese Highway, Mile 64.3 . .012 (?) Dredge concentrate; Deadwood Mining Co. mining operations on Nome Creek. 

Livengood area (fig. 6) 

<.001 

<.001 

<.001 

<.001 

. 003 

. 001 

.004 

<.001 

1.4:~ Mineralized zone in altered limestone; prospect shaft on Money Knob. 

Do. 

Iron-stained chert; prospect shaft on Money Knob. 

Altered shale; Livengood Ridge. 187:~ Weathered granite float; Livengood Ridge. 

Black shale; Livengood Ridge. 

Black siliceous rock; west spur of Amy Dome. 

Shear zone in basic volcanic rocks; west spur of Amy Dome. 

Basic volaanic rocks; west spur of Amy Dome. 

Coarse-grained diorite; Amy Dome. 

Diorite; Amy Dome. 

Weathered diorite; Amy Dome. 

Black shale; Livengood road at Olive Creek. 

1,500:~ Stream gravel; McCord Creek near mouth. 1,300:~ Bench gravel on bedrock; low bench of Tolovana River downstream 

from mouth of McCord Creek. 

Fissile black shale containing thin beds of gray sandstone; 

Livengood road just north of Tolovana River. 

250:1 Stream gravel from test pit; small unnamed tributary of Tolovana 

River on south side of Amy Dome, 2.1 miles east of Ester Creek, 

570:1 Stream gravel; Ester Creek near bridge over Livengood road. 

152:1 Black shale; Livengood road near Cleary Creek. 

Do. 

Conglomerate lens in black shale; Livengood road near Cleary Creek. 

Black shale; Livengood road about 1.2 miles east of Ester Creek. 

Do. 

(?) Sluice concentrate; Parkers' claims on Olive Creek • (?) Sluice concentrate after retorting; Parkers' claims on Olive Creek • 1,800:1 Stream gravel on bedrock; Jurich's claim on Lillian Creek. 

(?) Sluice concentrate; Well's cut on Amy Creek. 
1:\:l 

-'1 

R 

21 I 1456 

22 1544L 

23 ---- ~4a 1457A 

24b 1457B 

25a 

25b I ----

26 

27 1446A 

1446B 

28 1451 

la I 1459L 

lb 

lc 

2a 

2b 

2c 

2d 

3 

4a I 1460AL 

1460BL 

5a 

7a 

8a 

9a 

5b 

7b 

8b 

4c 

5c 

Be 

9c 

6 

lOal 1461 

lOb 

lla 

llb 

llc 

. 001 

<.001 

<.001 

<.001 

<.001 

0.006 

• 004 

. 004 

• 004 

• 002 

• 004 

.005 

• 003 

.0051 

.004 

• 003 

.004 

• 004 

.003 

.oo; 

.om: 

.0031 

i .003! 

.002 

. 0031 

.0031 

.001 

<.0011 

.003 

• 0031 

.002 

See footnotes at the end of the table. 

<.001 .001 

0.004 

.0021 0.0601 

<~001 

.002 

. 002 

.010 1 .009 

. 003 

8,790:1 Bench(?) gravel; rrom gravel pit on divide between Livengood and 

Hess Creeks. 

17:1 Weathered chert; south slope or Livengood Dome • 

-- Do. 

(?) Gravel rrom drirt dump pile; drirt on Goodluck Creek. 

200:1 Tailings; drirt on Goodluck Creek • Mineralized vein in altered limestone; north slope o£ Money Knob. 

Do. 

Rock material on mine dump; rrom drirt on vein at same location as station L 25. 

(?) I Coarse rraction or sluice concentrate; Radak's cut on Ruth Creek. 

(?) Fine rraction or sluice concentrate; Radak's cut on Ruth Creek. 

(?) Sluice concentrate; Benn Falls' workings on Wilbur Creek • 

Harding Lake--Richardson area (rig. 7) 

0.009 

• 110 

.0011 

1,910:~Weathered granite; south shore or Birch Lake on south side or Richardson Highway • Do • Fine-grained granitic dike; same location as station R la • Porphyritic granite; about 1 mile east or station R 1 on south side or Richardson Highway • Marie inclusion in granite; same location as station R 2a • Pegmatitic phase or granite; same location as station R 2a. 

Fine-grained phase or granite; same location as station R 2a • Weathered granite; about 500 reet east or station R 2 on north 

side or Richardson Highway. 

185:11 Fine-grained light-colored (granitic?) dike; same location as station R 3. 

(?) Do • 

Same as station R 4a • Do. 

Do. 

Do· • 

Weathered granite on northwest side or rine-grained dike; same location as station R 3. 

Do. 

Do. 

Weathered granite on southeast side or rine-grained dike; same location as station R 3. 

Do. 

Do • Do. 

Marie zone along side or dike; same location as station R 3. 

450:11Bench(?) gravel or Tanana River; south side or Richardson Highway, 

Mile 309.4. 

Do. 

Weathered porphyritic granite; south side or Richardson Highway, 

Mile 310.7 • Do. 

Marie inclusion in granite; same location aa station lla. 
t\:) 

co 

Table 1.--Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River valleys, Alaska--Continued 

Test 

station 

R 12 

13a 

13d 

l3b 

13c 

14a 

14b 

14c 

14d 

15 

16 

17 

18 

19a 

l9b 

19c 

20 

21 

22 

23 

24 

25a 

25b 

26 

27 

AH la 

lb 

Sample 

file 

no. 

1462 

1556L 

1463 

1464 

1465 

1466 

1557L 

1467 

1468 

OT 

Concen- Percent equivalent uranium tration Description and location 

0.004 

. 003 

.005 

• 004 

.005 

.004 

.002 

.002 

. 003 

.001 

.003 

.002 

• 004 

.003 

• 003 

.002 

<.ClOl 

.001 

.001 

<.001 

.002 

1 ucs 

0.004 

• 001 

I BC-CS I BC-PC ratio 

Harding Lake-Richardson area-Cont.inued 

0.005 

.005 

0.004 

.004 I 

. oo81 

1 .020 

.009 

.005 

.005 

430:1 

65:1, 

Stream gravel; left bank of Salcha River about 300 feet above 

highway bridge. 

Weathered granite; east shore of Birch Lake on north side of 

Richardson Highway • 

Do. 

Fine-grained light-colored (granitic?) dike; same location as 

station R 13a • Do. 

Coarse-grained granitic dike; Richardson Highway, Mile 313.9. 

Do. 

--- · Fine-grained border zone of granitic dike; same location as station R 14a. 

Quartz mica schist adjacent to granitic dike; same location as 

station R 14a. 

Granitic dike; Richardson Highway, Mile 314.5 • --- • Yellow-stained zone in schist adjacent to fractured quartz vein; 

Richardson Highway, Mile 314.7. --- ·Weathered igneous (granitic?) dike in schist; Richardson Highway, Mile 314.8. --- I Fine-grained mafic dike in schist; Richardson Highway, Mile .314.85. --- Weathered granite; Richardson Highway, Mile 304.65 . Iron-stained quartz vein in granite; Richardson Highway, Mile 304.65. 

Do • --- . Altered limestone containing streaks of graphitic schist and a few 

thin quartz veins; Richardson Highway, Mile 302.65. --- Dark-colored dune sand; Richardson Highway, Mile 301.75. 

950:1 Stream gravel; unnamed tributary of Tanana River at Mile 299.8, 

Richardson Highway • 660:1 Bench gravel; Banner Creek about 100 feet above highway bridge. 

1,590:1 Gravel from old drift dump; near mouth of Buckeye Creek. 

1,180:1 Bench gravel on bedrock; Tanana River at Mile 296.9, Richardson 

Highway. 

3:~ Graphitic schist; same location as station R 25a • 590:1 Gravel from old drift dumps; Tenderfoot Creek at Mile 293.7, 

Richardson Highway. 

790: Gravel from bottom of 100 foot shaft; claim 13 at Mile 292.1, 

Richardson Highway. 

Alaska Highway belt (fig. 8) 

1,830:~ Bench gravel; Berry Creek about 300 feet above highway bridge. 

4:~ Coarse-grained granite in bank of creek; same location as station 

AH la. 
1.\:) 

co 

.All lc 

ld 

2 

3 

4 

5 

6 

7 

8 

9 

lOa 

lOb 

ll 

12 

13 

14 

l5a 

l5b 

l6a 

l6b 

l7a 

l7b 

l7c 

18 

l9a 

l9b 

20 

2la 

2lb 

22 

23 

24 

25a 

25b 

25c 

25d 

26 

27a 

1470 

1471 

1472 

1473 

1474 

l559L 

1475 

1476 

1477 

1478 

1479 

1480 

l481L 

1482 

l660L 

l581L 

l483L 

• 002 

. 002 

.002 

.001 

.002 

.001 

.001 

• 002 

.003 

. 001 

. 002 

.003 

.004 

• 002 

.001 

.005 

.003 

.004 

.003 

.002 

.003 

.001 

• 002 

.002 

.002 

.093 

• 003 

.004 

. 001 

.004 

.003 

.003 

See footnotes at the end of the table. 

.003 .005 

• 003 . 004 

.005 .007 

.001 

.006 

.008 1 .001 

.003 

.007 

.003 

.003 

.003 

.003 

1 .008 

1 .064 

<.001 

i .025 

Stream gravel; same location as station AH la • Bench gravel; same location as station AH la • 790: l Stream gravel; Berry Creek about 0. 25 mile above highway bridge. 

1,630:1 Stream gravel; Sears Creek about 0.25 mile above highway bridge. 

1,010:1 Stream gravel; Dry Creek about 250 feet above highway bridge. 

670:1 Stream gravel; Little Gerstle River about 300 feet above highway 

bridge. 

560:1 Glacial gravel; Alaska Highway, Mile 1,387, near mouth of 

Johnson River. 

Granite; Alaska Highway, Mile 1,368.9 • 

8:11 Granite; Alaska Highway, Mile 1,368.7. 

520:1 Stream gravel; dhief Creek about 75 feet above highway bridge. 

Granite, unweathered; Alaska Highway, Mile 1,359.3 . Granite, weathered; Alaska Highway, Mile 1,359.3 • 280:11 Stream gravel; unnamed tributary of Tanana River at Mile 1,350, 

Alaska Highway. 

340:11 Stream gravel; flood channel of unnamed tributary of Tanana River 

at Mile 1,345, Alaska Highway. 

400: l Stream gravel; main channel of same creek as at station AH 12, crosses Alaska Highway at Mile 1,344.6. 

260:11 Stream gravel; Yerrick Creek about 100 feet above highway bridge. 

Granite (slope wash?); in road-metal quarry about 0.5 mile east 

of intersection of old road with Alaska Highway near Mile 1,335. 

180:11 Do. 

Weathered gneiss; Alaska Highway, Mile 1,292.1 • Crushed zone (gouge?) in weathered gneiss; Alaska Highway, 

Mile 1,292.1. 

2,200:11Weathered granite; Alaska Highway, Mile 1,292.8. 

Do. 

Do. 

Mafic (basalt?) dike in weathered granite; Alaska Highway, 

Mile 1,292.9. 

Weathered mafic (basalt?) rock along fracture in weathered granite; 

Alaska Highway, Mile 1,293.0. 

Yellow-brown rock in fracture zone in weathered granite; 25 feet 

west of location of station AH l9a. 

l30:11Dark-colored wind-blown silt(?), Alaska Highway, Mile 1,299.7. 

Weathered granite; Alaska Highway, Mile 1,304.0 • Iron-stained fracture zone in weathered granite; Alaska Highway, 

Mile 1,304.0. 

Cemented breccia zone in weathered granite; Alaska Highway, 

Mile 1,304.2 • 20:11Mafic dike in weathered granite; Alaska Highway, Mile 1,304.4 • Brown-black stained zone in weathered granite; Alaska Highway, 

Mile 1,308.5. 

Weathered granite; Alaska Highway, Mile 1,290.0 • 236:liLight-colored felsitic dike; Alaska Highway, Mile 1,290.0. 

Mafic dike; Alaska Highway, Mile l, 290.0 • Weathered granite; Alaska·Highway, Mile 1,290.0. 

2,700:11Weathered granite; Alaska Highway, Mile 1,286.9. 

Weathered fine-grained granite (dike?); Alaska Highway, 

Mile 1,283.8. 
~ 

0 

Table 1.--Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River valleys, Alaska--Continued 

Sample Test file station no. 

AH 27bl ---- 28 1484 

29a ---- 29b 1485 

30 1661L 

3la ---- 3lb 1662L 

32a ---- 32b ---- 32c ---- 32d ---- 33 1486 3l~a ----

34b ---- 35 1487 

36a ---- 36b 1546L 

37 

38 

39 

40 

41 

1488L 

1489L 

1547L 

1490L 

1560L 

TC 1 I 1491 

2 1492 

3 I 1493 

4 . 1494 

5 I 1495 

OT 

Concen- Percent equivalent uranium tration Description and location 

0.003 

• 004 

.004 

.003 

<.001 

• 003 

.002 

.002 

.001 

.001 

.001 

:<.001 

.003 

.004 

.004 

• 004 

.004 

. 004 

.004 

.004 

.001 

I ucs ____ j BC -CS l BC-PC ratio 

0.004 

.003 

...::.001 

.001 

.003 

j_ 

0.004 

.010 

• 023 

.013 

.002 

Alaska Highway belt--Continued 

0.002 

.005 

.006 

j_ .002 

1. .GlO 

.027 

.1. .074 

--- I Weathered coarse-grained granite; Alaska Highway, Mile 1,283.8. 

360:1 Stream gravel, but includes some reworked dark-colored windblown silt(?); Bitters Creek at Mile 1,282.2, Alaska Highway, 

about 300 feet above highway bridge • --- Weathered granite gneiss; Alaska Highway, Mile 1,278.7. 

5,600:1 Slope wash from weathered gran1.te gneiss; Alaska Highway, 

Mile 1,278.7. 

80:1 Rhyolite(?) dike; Alaska Highway, Mile 1,277.0. --- Hornblende(?) schist; Alaska Highway, Mile 1,269.8. 

1,120:1 Weathered felsitic(?) dike; Alaska Highway, Mile 1,269.8 • --- Granite near contact with schist; Alaska Highway, Mile 1,238.9. --- Quartzi tic schist; Alaska Highway, Mile 1, 238.9 • --- Schist near granite contact;_ Alaska Highway, Mile 1,238.9. 

Granite; Alaska Highway, Mile 1,238.9. 

930:11 Slope wash from schist; Alaska Highway, Mile 1,232.5. --- Weathered iron-stained rock (igneous?) in schist; Alaska Highway, 

Mile 1,230.3. --- Schist; Alaska Highway, Mile 1,230.3. 

4, 930: 1 Slope wash from· schist; Alaska Highway, Mile 1, 229 • 4. --- Hematite-stained granite; Alaska Highway, Mile 1,253. 

55:1 Weathered granite; Alaska Highway, Mile 1,253.2 • 7,820:1 Do. 

5,670:1 Weathered granite; Alaska Highway, Mile 1,257.4 • Weathered granite; Alaska Highway, Mile 1,257. 7. 

--- I Weathered granite; Alaska Highway, Mile 1,261.0 • 12:1 Weathered granite; Alaska Highway, Mile 1,263.1. 

1,680:1 Do. 

21:1 Sulphide-rich zone in granite; Alaska Highway, Mile 1,265.0 

(Northway Junction). 

Highway area between Slana and Tok Junction (fig. 9) 

0.001 

.001 

.001 

.002 

.003 

680:11 Stream gravel; Station Creek about 0.5 mile above highway bridge. 

680:1 Stream gravel; unnamed tributary of Mentasta Creek about 2.5 miles 

east of Station Creek, about 1 mile above highway bridge. 

270:11 Bench(?) gravel; unnamed tributary of Mentasta Creek about 4.5 miles 

east of Station Creek, about 0.5 mile above highway bridge. 

550:11 Pan gravel; unnamed tributary of Mentasta Creek about 6.6 miles 

east of Station Creek. 

890:1 Pan gravel; unnamed tributary of Mentasta Creek about 9.2 miles 

east of Station Creek. 
C.:> 

I-' 

RH 

6 I 1496 

711497 

.8 1498 

9 I 1499 

10 I 1500 

11 1501 

12a 

12bl 1503 

12c 1562L 

l2d 1561L 

12e 1502 

13 1504 

14 1505 

15 1506 

16 --- 17 1507 

18 1508 

19 1552A 

1552B 

1 I 1509 

2 I 1510 

3 I 1511 

4 1512 

5 I 1513 

6 1514 

7 I 1515 

8 1516 

<.001 

.001 

<.001 

<.001 

.001 

.001 

See footnotes at the end of the table. 

.005 

-<.001 

.001 

<.001 

.001 

.002 

.002 

.003 

<.001 

.003 

<.001 

. <.001 

<.001 

<.001 

:1. <.001 

.<.001 

.001 

<.001 

<.001 

170:11 Pan gravel from test pit; unnamed tributary of Little Tok River 

about 1 mile below Trail Creek, about 100 feet above highway 

bridge. 

590:11 Pan gravel in cut bank of stream; unnamed tributary of Little Tok 

River about 4 miles below Trail Creek, above highway bridge. 

590:11 Pan gravel in cut bank of stream; unnamed tributary of Little Tok 

River about 5.5 miles below Trail Creek, above highway bridge. 

350:11 Pan gravel in cut bank of stream; unnamed tributary of Tok River 

about 5.5 miles northeast of' location of station TC 8 .. 

230:11 Glacio-f~uvial gravel; in road cut, Tok River valley, at mouth of 

Little Tok River. 

670:1 Stream gravel; unnamed tributary of Tok River about 5.5 miles 

below Little Tok River. 

Weathered rock on mine dump; Silver Creek about 0.5 mile above 

tractor trail. 

l40:11Angular gravel {slope wash?) on low bench; same location as station 

TC 12a. 

3:1 Weathered bedrock; same location as station TC 12a. 

19:1 Sulphide-rich quartz vein; same location as station TC 12a. 

135:1 Stream gravel; same location as station TC 12a • 65:1 Pan gravel from cut bank; first right limit tributary of 

"Indian Pass" Creek. 

140:1 Pan gravel;. third left limit tributary of "Indian Pass" Creek. 

8,530:1 Pan gravel from test pit; first left limit tributary of 

"Indian Pass" Creek. 

Weathered diorite(?); Tok cutoff road near Mile 12. 

200:11Bench gravel on bedrock; second right limit tributary of Slana 

River above Porcupine Creek. 

(?) ~Sluice concentrate; upper workings on Grubstake Creek. 

(?) Sluice concentrate; Bronniche's workings on Slope Creek. 

(?2 Coarse fraction of sluice concentrate; Bronniche's workings on 

Slope Creek. 

Donnelly Dome--Paxson area (fig. 10) 

-< 0.001 

<.CJOl 

. 001 

<.001 

<.001 

.003 

. 003 

.002 

120:11Glacio-fluvlal gravel; Gulkana River about 1 mile below toe of 

glacier. 

400:11Pan gravel; right limit tributary of Phelan Creek about 4.5 miles 

above mouth of Phelan Creek • 250:11Pan gravel; right limit tributary of Phelan Creek about 3.5 miles 

above mouth of Phelan Creek. 

350:11Pan gravel; right limit tributary of Phelan Creek about 2 miles 

above mouth of Phelan Creek. 

300:11Bench gravel; Delta River about 0.25 mile below mouth of Phelan 

Creek, Yukon Corp. workings. 

480:1 Stream gravel; right limit tributary of Delta River about 

2.25 miles below Castner Creek • 500:11Stream gravel; right limit tributary of Delta River about 

3.25 miles below Castner Creek. 

310:11Stream gravel; right limit tributary of Delta River about 

4.25 miles below Castner Creek. 
co 

1::-:J 

Table 1.--Data on radioactivity tests in areas adjacent to highways in the Tanana and upper Copper River valleys, Alaska--Continued 

Sample Percent equivalent uranium ConcenDescription and location Test file tration station OT 1 ucs l BC-CS l 

RH 

no. 

9 1517 --- --- ---

10 1518 --- --- --- 11 1519 --- --- ---

12 1520 --- --- --- 13a 1521 --- --- --- l3b 1444 --- --- ---

14 1522 --- --- ---

15 1522A --- --- ---

1 Methylene iodide used instead of bromoform for concentration. 2 M.inus 6o-mesh fraction tested instead of minus 20·mesh fraction. 

BC-PC ratio 

Donnelly Dome--Paxson area--Continued 

0.002 360:1 Stream gravel; right limit tributary of Delta River about 

6.25 miles below Castner Creek. 

• 003 410:1 Stream gravel; Darling Creek about 0.25 mile above highway bridge • 

.004 480:1 Pan gravel in cut bank; Gunnysack Creek about 0.25 mile above 

highway bridge • 

. 003 (?) Stream gravel; Clear Creek below falls near highway • 

.004 430:1 Stream gravel; Ober Creek valley of DeWitt's workings. 

.007 (?) Concentrates from drill-hole pannings; Ober Creek valley, DeWitt's 

workings. 

.003 (?) Stream gravel on bedrock; Ober Creek valley, old Miller cut near mouth of Mineral Creek. 2 .011 (?) Panned concentrates obtained from operator; Ober Creek valley, 

old cut about 300 feet above location of station RH 14. ---~·-
CHAPTER B. -GRANT CREEK AREA 

By P. L. Killeen and M. G. White 

ABSTRACT 

In August 1946 field search failed to locate a. 

reported occurrence of float from pitchblende veins in 

the Grant Creek area north of the Yukon River about 

30 miles west of Tanana in eastern interior Alaska. 

The late Walter Fisher, placer-gold miner on Grant 

Creek, reported the occurrence to the Geological 

Survey. It is believed that fragments of black hematite 

were mistaken for pitchblende. 

INTRODUCTION 

Purpose and scope of i?vestigation 

In the fall of 1945 the late Walter Fisher, Alaskan 

placer-gold miner, reported to R. M. Chapman of the 

Geological Survey at Fairbanks an occurrence of pitchblende veinlets in hillside float along a tractor trail 

near his placer-mining property on Grant Creek in the 

Yukon valley. During the winter of 1945-46 no correspondence was exchanged with Mr. Fisher on the 

subject of the pitchblende because of the security regulations in effeCt at that time. 

In August 1946 a Geological Survey field party 

went to Grant Creek to investigate the reported pitchblende. The party consisted of P .. L. Killeen and 

M. G. White, geologists, and R. D. Hamilton, camphand. 

When the party arrived at Grant Creek, it was learned 

of Mr. Fisher's death earlier in the summer. The 

Fisher mine was closed, and none of the residents in 

the area had any information about the reported deposits. 

Thus, no direct information was available as to the 

location of the pitchblende, and_ a search was made of 

the area to determine whether the report had any 

significance. 

. Location of area 

Grant Creek enters the Yukon River from the 1

north about 30 miles west from Tanana in central 

Alaska. (fig. 11). The area is accessible from Tanana 

by boat. In addition to Grant Creek the following other 

areas were examined during this investigation: the 

headwaters of Tozimoran Creek, a tributary of the 

Tozitna River which enters the Yukon River about 

midway between Grant Creek and Tanana; and the 

headwaters of Melozimoran Creek, a tributary of the 

Melozitna River which enters the Yukon River in the 

vicinity of Ruby about 100 miles west of Tanana. 

GEOLOGY 

The geology of the Grant Creek area was discussed 

briefly by Maddren (1909, p. 234-237; 1910, p. 80-83) 

33 

and Eakin (1913, 1916). Maddren's two reports contain short accounts of the geology of the area gathered 

during brief investigations of the placer-mining activities in the area. Eakin's two reports were based 

on geological reconnaissance investigations on a regional scale in which the Grant Creek area is included. 

No details, however, of the areal distribution, age, 

and structural relations of the individual rock types in 

the Grant Creek area are known. 

The Grant Creek area is part of a broad zone of 

metamorphosed rocks that are well developed on the 

north side of the Yukon valley between the Koyukuk 

River and the Yukon Flats. The rocks are thought to 

be early Paleozoic in age. A complex of intensely 

folded and metamorphosed schist, limestone, quartzite, 

and greenstone occurs within the area. 

Pebbles with quartz stringers occur in the placer 

cuts on Grant Creek. The quartz stringers in the bedrock are probably the source of some of the placer 

gold. Some pebbles of a medium-grained pegmatite 

are also present in the gravels. 

A monzonite mass mapped by Eakin (1913, p. 16) 

at the head of Golden Creek (fig. 11) was not found. 

The rock a.t that locality consists of mica schist and 

greenstone. A granitic intrusion of unknown areal 

extent was found at the head of Melozimoran Creek. 

RADIOACTNITY 

The principal objective of the investigation in 

the Grant Creek area. was the examination of an area. 

adjacent to a tractor trail along which the late Walter 

Fisher had reported finding float from a. pitchblendebearing vein. When the search along this trail failed 

to reveal any deposits of radioactive materials, the 

investigation was extended to other trails and intervening areas. All possible materials representative 

of the bedrock in the area (outcrops, talus, and fragments selected from the soil mantle) were tested, 

particularly at places where there were traces of 

mineralization. Only a few concentrates of the heavy 

minerals in the stream gravels wer·e collected for 

testing (table 2). The radioactivity tests in the Grant 

Creek area were made with a portable survey meter 

designed by the Geological Survey. The background 

for this meter in this area. averaged 8 to 10 counts 

per minute. 

Locations of tests 

The main tractor trail in the Grant Creek area 

extends from the Yukon River to Fisher's camp on upper 

Grant Creek, a distance of about 4 miles (fig. 11). 

The southern portion of this trail has been shifted 
Lynx Dome 

X 

Grant Dome 

X 

0 

' I 

3 Miles 

Droinog e, from topographic mop by E. Mundine, 1941 

Figure 11. -Drainage map of the Grant Creek area, Yukon region, Alaska. 

34 
Table 2.--Data on placer concentrates from Grant and Tozimoran creeks, Alaska 

Equivalent Alaskan uranium content Concentration 

Concentrate of concentrate ratio 

file no. (percent) 

Location 

Grant Creek 

733 0.005 (?) Fisher's placer cut, 1942. 

1360 .cos S,llO:l Fisher's placer cut, 1946. 

5,125:1 Monday Creek, at footbridge about 60 feet above mouth, 

in Grant Creek valley. 

1361 .cos 

1362 

1363 

.005 1,790:1 Monday Creek, at tractor-trail crossing just above 

edge of Grant Creek valley. 

.007 

445 

11,350:1 Southern of two gulches on east side of Grant Creek, 

opposite Fisher•·s camp below Monday Creek. 

(?) Berton claim of the Tozi or Gold Hill district; probably from former prospects of Berton Anicish of 

Lynx Creek. 

rrozimoran Creek 

52S 0.001 (?) Tozimoran Creek, between its tributaries, Chicken and 

Ash creeks. 

721 (?) 

722 .001 (?) 

723 .001 (?) 

724 .001 (?) 

725 .001 (?) 

729 .001 (?) 

730 (?) 

731 .001 (?) 

739 .001 (?) 

successively uphill as the lower route became boggy. 

Traces of the older, abandoned parts of the trail still 

remain. A less distinct tractor trail runs via Lynx 

Creek and Windy Creek to some prospect pits. A third 

and more prominent trail, cleared by ax and bulldozer 

for a railroad survey, follows the north bank of the 

Yukon River eastward from the mouth of Grant Creek. 

It was included in the investigation because many of 

Fisher's more recently staked claims were in that general area. ·A few short old tractor trails.were found 

on the upper part of Grant Creek above Fisher's mine; 

some lead to wood lots, others to drilling sUes as far 

upstream as the mouth of Fox Gulch. Othe:P narrower 

lines have been brushed out along many of the boundaries of Fisher's claims. A prominent horse trail 

extends from Fisher's camp to the head of Tozimoran 

Creek via Grant Dome. 

All occurrences of bedrock along the above trails 

and in much of the intervening area were examined. 

Pieces of float were also tested. A portable survey 

meter was operated continuously over many parts of 

the trails, and individual stations were selected arbitrarily for taking 5-minute readings. No radioactive 

material was indicated by these tests. 

A short time was spent investigating the area in 

the vicinity of the headwaters of Tozimoran Creek. At 

this locality galena veins occur on the south side of the 

creek, and cassiterite is present in the gravels. The 

source of the cassiterite could not be located. No other 

evidence of important mineralization was found, and no 

appreciable radioactivity was detected anywhere in the 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

35 

area. In table 2 are listed the available data on samples 

from Tozimoran Creek. 

An attempt was made to examine the granitic intrusion on Melozimoran Creek, but a heavy snowfall 

restricted the examination to a few tests with the 

portable survey meter. The radioactivity of the intrusion averaged 20 counts per minute as compared to 

an 8- to iO-count per minute average on the adjacent 

metamorphic rocks. 

CONCLUSION 

The investigations in the Grant Creek area 

disclosed no float rock corresponding to Fisher's 

reported description of his pitchblende-bearing vein 

float material. The only material that appeared to 

fit his description was schist containing a. few 

narrow streaks of limonite, but this was found on 

the west side of Windy Creek near its headwaters 

and a considerable distance from any tractor trail. 

It is improbable that this occurrence of limonite is 

the float referred to by Fisher. Sufficient search 

was made of the hillsides to conclude that the 

pitchblende vein or veinlets as reported by Fisher 

probably do not exist. 

Two fragments of a black platy mineral that were 

seen among the samples in Fisher's camp may have 

been collected from hillside float rather than from 

his placer workings. If this is true, Fisher's "pitchblende" is probably black hematite. 
LITERATURE CITED 

Eakin, H. M., 1913, A geologic reconnaissance of a 

part of the Rampart quadrangle, Alaska: U. S. Geol. 

Survey Bull. 535. 

____,=-=--=--=-1916, The Yukon-Koyukuk region, Alaska: 

U. S. Geol. Survey Bull. 631. 

36 

Maddren, A. G., 1909, Placers of the Gold Hill district [Alaska], in Brooks; A. H. , and others, Mineral 

resources of Alaska, report on progress of investigation 

in 1908: U. S. Geol. Survey Bull. 379-E, p. 234-237. _..,....... ___ 1910, The Innoko gold-placer district, 

Alaska, with accounts of the central Kuskokwim 

Valley and the Ruby Creek and Gold Hill placers: 

U. S. Geol. Survey Bull. 410. 

INT.-DUP. SEC., WASH., D.C.af)t'J