GEOLOGICAL SURVEY CIRCULAR 350

OCCURRENCES OF URANIUM 

IN CARBON COUNTY 

PENNSYLVANIA

aP'r-t'-TY OF

-U. S. aFFiCE

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 

Douglas McKay, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

GEOLOGICAL SURVEY CIRCULAR 350

OCCURRENCES OF URANIUM IN CARBON COUNTY, PENNSYLVANIA

By Harry Klemic and R. C. Baker

This report concerns work done on 

behalf of the U. 8. Atomic Energy 

Commission and is published with 

the permission of the Commission.

Washington, D. C., 1954

Free on application to the Geological Survey, Washington 25, D. C.
Geology by Harry Klemic, modified after Winslow

Figure 1. Map of uranium occurrences in Carbon County, Pa.

ii
OCCURRENCES OF URANIUM IN CARBON COUNTY, PENNSYLVANIA

By Harry Klemic and R. C. Baker

CONTENTS

Abstract......................

Introduction ...................

Location.................

Development and ownership. 

Geology........................

Stratigraphy..............

Catskill formation ... 

Pocono formation.... 

Mauch Chunk shale... 

Pottsville formation.. 

Allegheny formation ..

Page

1

1

2

2

2

2

2

3

3

3

3

Mineralogy...............

Uranium occurrences.....

Mount Pisgah.......

Mauch Chunk Ridge.,

Butcher Hollow......

Perm Haven Junction 

Results of analyses ......

Conclusions and plans....

Literature cited .........

Unpublished

report................

ILLUSTRATIONS

Figure 1. Map of uranium occurrences in Carbon County, Pa...............................

2. Sketch of outcrop of uraniferous rock near Penn Haven Junction, Carbon County, Pa.

TABLES

Table 1. Uranium minerals found in Carbon County, Pa.....................................

2. Results of semiquantitative spectrographic analyses of radioactive sandstone from

Carbon County, Pa............................................................

3. Equivalent uranium and uranium content of radioactive sandstone from Carbon County, Pa.

Page

3

3

3

5

5

5

7

7

Page

Page

ABSTRACT

An occurrence of uranium in Carbon County, Pa., 

was known in 1874. Three other deposits were discovered in 1948 and 1953 by reconnaissance parties 

of the U. S. Geological Survey.

Uranium vanadates, carbonates, and silicates 

occur in coarse graywacke conglomerate near the 

base of the Pottsville formation, of Pennsylvanian 

age, on the north limb of the Panther Valley syncline; and on the south limb, autunite and uranium 

silicates occur in graywacke sandstones near the 

top of the Catskill formation of Devonian age. 

Uraniferous graywacke sandstone occurs in the 

upper part of the Catskill formation near Butcher 

Hollow and near Penn Haven Junction in minor 

anticlines of the Broad Mountain anticline. Small 

amounts of kasolite and galena occur in the vicinity of Penn Haven Junction. All three uranium 

deposits in the Catskill formation appear to be 

in the Cherry Ridge redbeds of Willard (1939).

The presence of 4 uranium deposits in rocks of 2 different types and ages, within a limited area, suggests that 

other deposits maybe found by additional prospecting. Detailed study and geologic mapping of the area are planned.

INTRODUCTION

An occurrence of uranium in Carbon County, Pa., 

was known as early as 1874 when Genth (1875) reported 

autunite near Mauch Chunk but did not give the exact location of the deposit. Wherry (1912) described a deposit of 

carnotite northwest of Mauch Chunk, which he believed to 

be the one reported by Genth. More recently, McKeown 

(1949) found a uranium deposit southeast of Mauch Chunk. 

In July 1953 two occurrences of uranium north of Mauch 

Chunk were discovered by the writers during a reconnaissance for radioactive materials.

This report concerns work done on behalf of the 

Division of Raw Materials of the U. S. Atomic Energy 

Commission.
Location

All known occurrences of uranium in Carbon County 

are in the valley of the Lehigh River within 6 miles of 

Mauch Chunk (fig. 1). The deposits have been named 

Mount Pisgah, Mauch Chunk Ridge, Butcher Hollow, 

and Perm Haven Junction.

The Mount Pisgah deposit is located along 

a roadcut of U. S. 309 on Mount Pisgah, half a 

mile northwest of Mauch Chunk. The Mauch Chunk 

Ridge deposit is exposed along the right-of-way 

of the Central Railroad of New Jersey and also 

in a roadcut along U. S. 309 on Mauch Chunk 

Ridge about 0.4 mile southeast of Mauch Chunk, 

and on the northeast side of the Lehigh River 

about 1 mile southeast of Mauch Chunk. The 

Butcher Hollow deposit is exposed along the rightof-way of the Lehigh Valley Railroad on the west 

and east sides of the Lehigh River about 4 miles 

north of Mauch Chunk and about 1.5 miles south 

of Penn Haven Junction. The Penn Haven Junction 

deposit is exposed about 5 miles north of Mauch 

Chunk and about 0.4 mile south of Penn Haven 

Junction on both sides of the Lehigh River.

Development and ownership

The Mount Pisgah carnotite deposit has recently 

been prospected by the Lehigh Coal and Navigation Co., 

owners of the property. The Mauch Chunk Ridge deposit 

is owned partly by the Lehigh Coal and Navigation Co., and partly by Mr. Stuart Evans of 

Mauch Chunk. This deposit was prospected by core 

drilling during 1953. The Butcher Hollow and Penn 

Haven Junction deposits are on land owned by the 

Lehigh Valley Railroad Co. on the west side of the 

river and on land owned by the Commonwealth of 

Pennsylvania on the east side of the river. No development work has been done at either deposit.

GEOLOGY

Carbon County, in the central part of eastern 

Pennsylvania, has an area of 406 square miles. Maximum relief in the county is about 1, 840 feet, from 

Lake Mountain in Kidder township (2,220 feet) to Lehigh Gap (380 feet), where the Lehigh River flows from 

the county. The Lehigh River and its tributaries drain 

the entire county except for a small area in the southwestern part which is drained by a tributary of the 

Schuylkill River.

During Pleistocene time the Wisconsin and 

Illinoian ice sheets covered the northern part of 

the county. In places on the Pocono Plateau the 

glacial drift is more than 100 feet thick. The 

Jerseyan ice sheet covered the entire county, but 

there are no extensive deposits of Jerseyan drift 

except in the southern part.

Uranium occurrences in Carbon County, Pa., 

are in Paleozoic sedimentary rocks near the southwestern corner of the Pocono Plateau and the 

eastern end of the Southern Anthracite field (fig. 1). 

The Pocono and Catskill formations crop out on 

the plateau and extend southwestward across the 

Lehigh River in the Broad Mountain anticline.

On the southeast side of the anticline they dip 

below the surface as part of the Panther Valley 

syncline, emerging with almost vertical dips to 

form Mauch Chunk Ridge on the southeastern side 

of the syncline. On the north side of the Broad Mountain anticline the Pocono and Catskill rocks dip northward beneath the coal basins of the Eastern Middle 

Anthracite field. The Pottsville formation crops out 

to form a resistant rim around the coal basins. The 

less resistant Mississippian red beds of the Mauch 

Chunk shale have been deeply eroded and underlie the 

valleys between the ridges of Pottsville and Pocono 

rock.

Stratigraphy

The stratigraphic section of Carbon County includes Pennsylvania^, Mississippian, Devonian, and 

Silurian rocks. The geologic units in Carbon County 

and their thicknesses (Lesley, 1885) are listed below. 

Only the formations present in the vicinity of the uranium occurrences will be discussed in detail.

Stratigraphic section along the Lehigh River in 

Carbon County, Pa.

Pennsylvanian:

Productive coal measures 

Pottsville conglomerate 

Mississippian:

Mauch Chunk shale 

Pocono gray sandstone 

Devonian:

Catskill red sands and shales 

Chemung and Portage shales and flags 

Genesee shale 

Hamilton shale 

Marcellus shale 

Oriskany sandstone 

Helderberg limestone, lower part 

Silurian:

Onondaga and Clinton red and gray shale and 

marl----------------------------------------

Tuscarora sandstone--------------------------

Oneida conglomerate--------------------------

Feet

- 975

- 880

-2170

-1255

-1290

- 290

- 760

- 800

- 3^0

- 295

-2000

- 665

- 460 

19325

Catskill formation

The Catskill formation of Middle and Late Devonian 

age crops out over about 110 square miles of Carbon 

County on the Pocono Plateau and south of the Southern 

Anthracite field. Willard (1939) assigns a thickness of 

about 6, 000 feet to the Catskill rocks, from the base of 

the Pocono formation to the top of the highest marine 

strata in the Lehigh Valley. The rocks are composed 

of continental sediments with red shales and sandstones, 

and gray, green, and brown sandstone and conglomerate 

members. Willard (1939) subdivides the Catskill formation, from top to bottom, as follows:

Member

Mount Pleasant red shaleElk Mountain sandstone 

Cherry Ridge red bedsHonesdale sandstone 

Damascus red shale 

Lithology

Red shale and sandstone.

Green to grayish-green flaggy 

crossbedded sandstone.

Red shale and sandstone and 

quartz conglomerate.

Greenish to gray flaggy sandstone with some red beds.

Red shale.
Pocono formation

The Pocono formation of Mississippian age 

crops out in areas totalling about 95 square miles 

in Carbon County. The formation consists of massive beds of gray and greenish-gray sandstone and 

conglomerate. On the south side of Mauch Chunk 

the top unit of the Pocono formation is massive 

gray sandstone. Below this is a series of sandstone and conglomerate beds. Near the bottom of 

the formation is a massive conglomeratic member 

which resembles some parts of the Pottsville formation. Underlying this member are gray and tan 

sandstones and some red beds. The Pocono-Catskill 

contact is difficult to define. For want of a more 

exact boundary, the top of the first red bed member below the massive conglomerate beds is called 

the Pocono-Catskill contact in this area.

The Pocono formation is well exposed in the 

Lehigh Valley near Mauch Chunk. Winslow(1887) gives 

the following thicknesses for the formation in 

Carbon County:

Location

Mauch Chunk---------

Glen Onoko-- -- 

Perm Haven JunctionStony Creek---------

Drakes Creek-------

Feet

1255

1225

855

798

Mauch Chunk shale

The Mauch Chunk shale of Mississippian age crops 

out in about 60 square miles of western Carbon County. 

Its type locality is at Mauch Chunk, whereitis 2,168 feet 

thick. It consists of red shale, sandstone, mudstone, and 

siltstone, with thin beds of green, yellow, and tan shale. 

Calcareous concretions are present locally along some 

horizons but are not sufficiently developed or persistent 

to be useful for correlation over wide areas.

Pottsville formation

The Pottsville formation of Pennsylvanian age 

crops out in about 15 square miles of Carbon County 

in ridges around the eastern end of the Southern and 

Eastern Middle anthracite fields. It has a thickness 

of 1,155 feet in Nesquehoning Gap, 878 feet on Mount 

Pisgah east of the Panther Creek basin, and about 

300 feet near the Beaver Meadow basin of the Eastern 

Middle coalfield. The most prominent features of the 

formation are its massive quartz conglomerate members, which crop out on the crests of ridges and weather 

into huge blocks and boulders. There are thin beds of 

coal and black shale in the upper half of the formation. 

Red shale and red and tan sandstone occur in the lower 

half of the formation in beds that are more than 100 feet 

thick in places. One red and tan shale and sandstone 

member, 30 to 40 feet thick, persists over wide areas. 

Coarse conglomerate members occur above and below 

this red bed horizon.

The basal member is a coarse graywacke conglomerate and sandstone. It differs from the coarse 

conglomerate beds at the top of the Pottsville in that 

it contains abundant dark rock fragments that form a 

dark matrix around the white quartz pebbles. The

lithology of this member is not uniform. Sandstone 

and conglomerate lenses interfinger and thin and thicken. 

Small lenses of black siltstone and shale and porous 

brown sandstone are interbedded with the upper part of 

this conglomeratic member. Some of the conglomerate 

has graded bedding and crossbedding, particularly in 

the finer grained parts. Gray and tan coarse-grained 

sandstone at the base of the Pottsville formation grades 

into red and gray sandstone of the Mauch Chunk shale, 

so that an exact plane of demarcation cannot be drawn 

between the formations. Where the basal conglomerate 

member of the Pottsville formation and the upper part 

of the Mauch Chunk shale are obscured by talus, the 

lowest red bed member of the Pottsville formation 

closely resembles Mauch Chunk shale.

Allegheny formation

The Allegheny formation is a post-Pottsville 

formation of Pennsylvanian age. It consists of 

sandstone, conglomerate, shale, coal, and underclays. The Mammoth bed of the Allegheny formation is the most important coal bed in Carbon County. 

Lesley (1885) reports an average thickness of 

29 feet for the Mammoth bed in the Panther Creek 

basin east of Nesquehoning. Because of its thickness and because it has been extensively mined, 

it is a key member for interpreting structure and 

for correlating coal beds within a coalfield and 

between adjacent fields. Most of the coal produced 

in Carbon County has been from the lower 300 to 

500 feet of the Allegheny formation, 'from the top 

of the Mammoth bed to the bottom of the Buck 

Mountain or "B" bed, which is considered the lowest coal bed of the formation. An area of approximately 16 square miles in Carbon County is underlain by the Allegheny formation: about 7 square 

miles in the Panther Creek basin at the eastern 

end of the Southern Anthracite field and 9 square 

miles in the Eastern Middle Anthracite field.

MINERALOGY

Uranium occurs in unidentified black material 

disseminated in the Pottsville and Catskill formations. It also occurs in secondary minerals, some 

of which have been identified. They are listed in 

table 1.

The rocks containing uranium are composed chiefly 

of quartz, feldspar, muscovite and biotite, calcite, and 

rock fragments; with a chlorite and clay matrix in the 

Catskill formation; and a calcite cement in the Pottsville 

formation. Minor amounts of apatite, tourmaline, zircon, 

andpyrite are also present. Galena occurs in the uranif erous rock in the vicinity of Perm Haven Junction. 

Fragments of carbonaceous material are common in the 

Pottsville formation and unusual in the Catskill formation.

URANIUM OCCURRENCES 

Mount Pisgah

The Mount Pisgah uranium deposit, exposed in 

cliffs along the highway between Mauch Chunk 

and Nesquehoning, is in the basal sandstone and 

conglomerate member of the Pottsville formation.
Table 1. Uranium minerals found in Carbon County, Pa.

[Mineral identifications by A. D. Veeks, D. D. Riska, and B. R. Thompson. Chemical compositions from Frondel and Fleischer (1952)1

Mineral Chemical composition Locality

Phosphate:

AutuniteVanadates:

Carnotite--- 

TyuyamuniteCarbonate:

Liebigite 

Silicates:

KasoliteUranophaneBe ta-uranophane -

Ca(UO 2 ) 2 (P04 ) 2 ' 10-12H2 0-

K 2(U0 2 ) 2 (V04 ) 2 -3H2 0- 

Ca(U0 2 ) 2 (V0 4 ) 2 -nH 2 0-

Ca 2U(C0 3 ) 4 -10H2 0-

Pb(U02 )Si0 4 .H 20 - 

Ca(U0 2 ) 2 Si 2 0 7 -6H2 0-

Ca(U0 2 ) 2 Si 2 0 7 -6H2 0-

Mauch Chunk Ridge,

Mount Pisgah. 

Do.

Do.

Mauch Chunk Ridge. 

Penn Haven Junction, 

Mount Pisgah. 

Mauch Chunk Ridge. 

Penn Haven Junction. 

Mount Pisgah.

The rocks have been folded into a tight 

syncline, the Panther Valley syncline, which 

strikes approximately S. 80° W. and plunges 

to the southwest at an angle of 5° as measured 

along the base of the Mammoth bed. The dip 

of the north limb of the syncline is about 45° 

to the south, whereas the dip of the south limb 

ranges from steep to the north, through vertical, to slightly overturned. Where the strata 

curve around the nose of the syncline, as on 

Mount Pisgah, the dip progressively decreases 

toward the axis.

The Lehigh River has cut its valley to the 

base of the Pottsville formation near the east 

end of the syncline so that no part of that formation is present on the east side of the 

river.

A discontinuous zone of uraniferous sandstone and conglomerate extends about 2,000 feet 

along the north limb of the syncline westward 

from the axis of the syncline. Near the western 

end of the zone, core drilling found discontinuous radioactive rock about 240 feet downdip 

from the outcrop. Near the center of the zone 

a drill hole ended in uraniferous rock about 

100 feet downdip. A test adit driven horizontally into the rock about 25 feet started in 

uraniferous rock and ended in barren rock.

The mineralized rock varies in stratigraphic distance from an overlying sandstone 

and shale member. The easternmost exposure 

of uraniferous rock south of the highway is in 

a lens of conglomerate that wedges into the 

overlying sandstone. At the test adit near the 

western end of the uraniferous rock, more

than 10 feet of massive conglomerate separates 

the uraniferous rock from the overlying sandstone and shale member.

The uranium content of the mineralized 

rock ranges from a few thousandths of a percent to a few tenths of a percent in a distance 

of a few feet along the strike.

The uranium occurs as yellow and yellowishgreen minerals coating fracture surfaces and 

slickenside surfaces and as incrustations on 

loosely cemented quartz pebbles in coarse conglomerate. Fine cracks which penetrate both 

the pebbles and the calcite cement are filled 

with yellow minerals in many places. Uranium 

is also present in unidentified black material 

in the matrix of the rock and in very fine 

cracks in quartz pebbles.

Secondary uranium minerals were observed 

on surfaces of rock which had been broken 

only a few months previously, indicating that 

uranium is present in tightly cemented rock 

in a form that is unstable under present conditions of weathering. The absence of secondary uranium minerals in uraniferous rock in 

drill cores, except where they cut fractures and 

bedding-plane surfaces, indicates that the massive parts of the rock have not been deeply 

weathered.

Carnotite, tyuyamunite, liebigite, uranophane, and beta-uranophane have been identified 

in the Mount Pisgah deposit. An attempt is 

being made to isolate and identify the black 

radioactive material that occurs in the matrix 

of the rock.
Mauch Chunk Ridge

Uraniferous sandstone is exposed in a roadcut 

along U. S. 309 and along the tracks of the Central 

Railroad of New Jersey between Mauch Chunk and 

Packerton. The sandstone is in the Cherry Ridge red 

beds (WiUard, 1939) of the Catskill formation on the 

south limb of the Panther Valley sync line. The bedding 

strikes N. 60° E. and dips from 80° NW. to vertical 

or slightly overturned.

From Mauch Chunk the Lehigh River flows southward for a quarter of a mile, then turns northeastward 

and follows the strike of the Catskill formation in a 

valley about 800 feet deep. About a mile east of Mauch 

Chunk the river turns sharply to the southeast and cuts 

across the upper units of the Catskill formation.

Uraniferous rock occurs discontinuously for about 

1 mile along the strike and 700 feet along the dip of the 

Catskill formation between the top of Mauch Chunk Ridge 

near Flagstaff Park and the east side of the river where 

the Lenigh Valley Railroad tracks cross the river.

Most of the uraniferous rock exposed in the roadcut is in two beds of sandstone separated about 25 feet 

stratigraphically. The upper bed is 4 to 8 feet thick; 

the lower bed, 4 to 6 feet thick. Along the tracks of 

the Central Railroad of New Jersey at approximately 

the same stratigraphic position as the lower bed of the 

roadcut are four radioactive outcrops within a strike 

length of 2, 700 feet. In addition, a few thin beds of 

radioactive shale and sandstone lie stratigraphically 

between the upper and lower beds of the roadcut. None 

is more than 1 foot thick and all are less radioactive 

than the main sandstones.

The sandstone is composed mainly of quartz, 

feldspar, muscovite, and phlogopite in a matrix of 

chlorite and clay. Chips of shale occur in some of the 

beds. Minor amounts of tourmaline, zircon, and apatite are accessory. Autunite, kasolite, and uranophane 

occur on joint surfaces and in cracks in the rock but are 

not conspicuous on the outcrops. Most of the radioactive material is in an unidentified black or gray 

material disseminated in the matrix.

Samples of radioactive rock (HK3-35, -36, -37, 

table 3) contain from 0. Oil percent to 0.13 percent 

uranium.

Butcher Hollow

Near Butcher Hollow, about 4 miles north of 

Mauch Chunk, uraniferous rock is exposed in the gorge 

of the Lehigh River at an approximate elevation of 

710 feet near the level of the tracks of the Lehigh Valley 

Railroad on the west side of the river. The uranium 

is in the upper part of the Catskill formation. It may 

be at about the same stratigraphic position as that in 

which the uranium occurs on Mauch Chunk Ridge, but 

no measurements have been made to confirm this 

possibility.

The uraniferous rock is on the south limb of a 

local anticline near the crest of the Broad Mountain 

anticline. On the east side of the river uraniferous 

rock occurs in talus at approximately the same elevation and the same stratigraphic position as the

mineralized rock in outcrops on the west side of the 

river. The distance between these two points is about 

500 feet. The uraniferous rock dips 15° S., and the 

north limb of the anticline dips 50° N. The sandstone 

of the south limb of the anticline is not uniformly radioactive. There is a mineralized zone about 20 feet long 

with a stratigraphic width of 6 feet. Within this zone, 

are some shaly and silty members and some poorly cemented, limonitic parts of the sandstone, with abundant 

shale chips. These rocks are penetrated by fractures 

and are more strongly radioactive than the rest of the 

rock. No uranium minerals from this deposit have 

been identified.

The average uranium content of 4 samples (HK3- 

39, -40, -41, -42, table 3), representing about 2 feet of 

the 6-foot interval of sandstone, is 0.016 percent. A 

selected sample (HK3-49, table 3) of radioactive rock 

from the talus on the east side of the river has a uranium content of 0.055 percent.

Penn Haven Junction

Uraniferous rock is exposed on both sides of the 

Lehigh River at an elevation of about 720 feet about 

0.4 mile south of the railroad station at Penn Haven 

Junction. The uranium is in the upper part of the 

Catskill formation at about the same stratigraphic 

position as that on Mauch Chunk Ridge. It occurs in 

a local anticline on the north limb of the Broad Mountain 

anticline. On the east side of the river the uraniferous 

rock crops out along an abandoned railroad bed. No 

detailed sampling of the rock or measurement of the 

radioactivity at this outcrop has been done. In general, 

the extent of the radioactive rock and the intensity of 

the radioactivity on the east side of the river is less 

than that at the outcrop on the west side of the river 

about 500 feet away.

On the west side of the river the uraniferous rock 

crops out along the tracks of the Lehigh Valley Railroad 

for about 300 feet between the track level and about 

10 feet above the track level. A small spring flows from 

the ground near the southern end of the zone of uraniferous 

rock. The uranium appears to be concentrated on the 

limbs of the anticline, particularly on the north limb 

(fig. 2). In general, the uraniferous zone cuts obliquely 

across the dip in a fairly horizontal band. Within this 

zone the uranium minerals follow the bedding, but in 

places the amount of uranium varies abruptly with no 

apparent change in lithology and no extensive fracture 

in the rock.

The mineralized rock is gray to greenish-gray 

medium-grained graywacke that weathers tan and, in 

places, is stained black. Although some of the black 

stain is probably due to manganese oxides, much of 

it is soot from locomotives. Galena and pyrite occur 

in some of the more strongly radioactive parts of the 

rock. Some of the galena is granular. The grains are 

angular to rounded, equant, range from about 0.05 millimeter to 1.0 millimeter in diameter, and are disseminated in layers a few millimeters thick. Because 

the grains are partly rounded and because some of them 

occur in layers parallel to the bedding, they resemble 

detrital grains or pseudomorphs of detrital grains. 

Galena and pyrite also occur as irregular-shaped masses, 

either as open-space fillings or as a replacement of 

material in the matrix, and conform in shape to spaces
EXPLANATION

Thin-bedded to shaly sandstone

Location and length of chip sample Rodiooctivtyof outcrop

In milliroentgens per hour

Sample number ond 

Equivalent uranium content

Geo

Figure 2. Sketch of outcrop of uraniferous rock near Perm Haven Junction, Carbon C
between the clastic grains. This galena appears to 

have crystallized in place and at least in its present 

form is not detrital. In places pyrite is crystallized 

around the edges of and between the irregular masses 

of galena. In one hand specimen a mass of pyrite about 

4 millimeters by 6 millimeters in cross section and 

about 11 millimeters long appears to have replaced 

fibrous plant material. The pyrite has a columnar 

appearance, and many of the columns are partly or 

wholly surrounded by black opaque material. The 

general appearance is that of pyrite filling cells and 

partly replacing cell walls in a piece of carbonized 

plant stem.

The rock that contains the sulfide is slightly 

darker than the remainder. In and near the dark zones 

some fine-grained yellowish-brown and pale translucent 

green materials in the matrix of the rock form elongate 

streaks parallel to the bedding.

Kasolite and an unidentified yellow fluorescent 

mineral, probably uranophane, occur sparingly as 

flakes and incrustations on bedding-plane and fracture 

surfaces. Uranium in an unidentified form also is disseminated in the rock. The weathered surface of one 

specimen of sandstone is less radioactive than the 

freshly broken surface. This suggests that the intensity 

of radioactivity at the outcrop is related to disseminated 

uranif erous material in the rock and not to an accumulation

of secondary uranium minerals on the weathered surfaces. Assays of 13 samples (HK3-43 to -45 and -52 

to -61, table 3) weighted against the lengths of the 

samples, average 0.053 percent uranium. A selected 

sample (HK3-50, table 3) from a highly radioactive 

zone on the east side of the river contains 0.30 percent uranium. The uranium content of samples from 

the Penn Haven Junction deposit ranges from 0.001 to 

0.56 percent.

RESULTS OF ANALYSES

The results of semiquantitative spectrographic 

analyses and determinations of equivalent uranium and 

uranium in samples taken from the occurrences in the 

Catskill formation are given in tables 2 and 3.

CONCLUSIONS AND PLANS

Uranium minerals have been found in Carbon County, 

Pa., in the Catskill formation at 3 different localities, and 

in the Pottsville formation at 1 locality. Additional 

prospecting may locate other occurrences where the 

Pottsville, Catskill, and adjacent formations crop out. 

Prospecting may further be guided by rock type. The 

known occurrences of uranium in Carbon County 

are all in gray or greenish-gray sandstone or

Table 2. Results of semiquantitative spectrographic analyses of radioactive sandstone from

Carbon County, Pa.

[Analyses by Charles Annell]

Percentage

Yn

 _ _______________

ox _ - _ _ _ _ - _ - ___

.oox 

.oooox 

Mauch Chunk Ridge

HK>36

Si

Fe

Mg

Ti

Ba

Ca

Na

Pb

Sr

B

Cu

Mn

Co

Cr

V

Ni

Ga

Zr

Y

Sc

Be

Yb

HKJ-37

q-5 Ol

Fe

K

Mg

Ca

Ti

Pb 

Na

V

Ba

B

Mn

Cu

Ni

Cr

Sr

Ga

Y

Zr

Yb

Butcher Hollow

HK>4l

JT.JL AT

Si

Fe

Mg

Ca

Na

Ti

Ba

Pb

B

Mn

V

Co

Ga 

Cr

Ni

Sr

Cu

Y

Sc

Be 

Yb

HK3-43

Fe

Mg

Ca

U

Ti

Pb

Mn

Ba

Na

B

V

Co

Cu

Ni

Cr

Y

Sr

Ga

Yb

Penn Haven Junction

HK3-45

04

Ol

Fe

K

Mg

Ca

Ti

U

Pb 

Na

Ba

B

Mn

V

Co

Ni

Ga

Cr

Cu

Sr

Y

Yb

HK5-50

0-!

Ol

Fe

Mg

Ca

Ti

Pb

U

Ba

Mn

V

Na

B

Co

Ni

Cu

Y

Cr

Ga

Sr

Yb

HK5-61

Si

K

Mg

Ti

Ca

Na

Ba

Mn

B

Co

Pb

Ni

V

Ga 

Cr

Sr

Zr

Cu

Y

Sc

Yb 

Be
Table 3. Equivalent uranium and uranium content, in percent, of radioactive sandstone from

Carbon County, Pa.

[Radioactivity measurements (eU) by B. A. McCall; chemical analyses (U) by Esma Campbell]

Location and sample no.

Mauch Chunk Ridge:

^6

Butcher Hollow:

40 - - 

42 1

49 __

Penn Haven Junction: 

HK3 43 

44- -

50 *

CO

53 

54 

55- 

eg ____________

r-O 

5S 

59 _____ _ _ __ _ ___

60 - 

61 

Type of sample

Grab 

 do 

 do 

Chip 

 do 

. do 

Chip- - 

Chip 

Grab 

Chip 

 do 

 do 

 do 

 do 

 do 

Length of 

sample 

(feet)

0.5

 5

.5

 5

1.0

1.0

5-0

1.5 

2.0

4.0

7.0 

6.0

7.0

2.5 

6.0

2

r- 5

.5

eU

0.034

.017

.10 

.004

.048, 0.047

.026, .027

.004

.063

oc o 

.60r\-7 23

.32 

.006

.032

.003 

.008

y-\-i Q

.040

.002

.008

.019, -016

.017, .016

0.030,

 W_l_t_ y

 13,

.002, 

.040,

 \JLLLL y

.002.,

.060,

. CLCL,

* j*~> 56 >

 '-'->

 30,

.003,

.031,

.001,

.005,

. vi-3>

r\~zQ .030,

.001,

.005,

.008, 

.026,

U

0.031 

.011

.13

.003

r\~zQ

.022

.001

. -055 

.24

. ^^^6j

.22

 zo yj

.003

.030

.001

.005

.015

f\-zQ

.001

.005

.009

.025

'* Sample from east side of Lehigh River.

conglomerate; none is in red sandstone or shale. 

One of the constituents that causes the gray color in 

the rocks is finely disseminated carbonaceous matter. 

As carbonaceous matter is associated with many uranium deposits in sandstone and is used as a criterion for "favorable ground" for carnotite deposits 

on the Colorado Plateaus (Weir, 1952, p. 22), 

it also may indicate "favorable ground" in 

Pennsylvania.

Geologic mapping on aerial photographs and 

detailed reconnaissance of about 100 square miles 

in the vicinity of the known uranium occurrences 

in Carbon County are planned. The purpose of 

this study will be to determine the relationships 

of the uranium occurrences to the structure and 

stratigraphy of the region, to search for additional occurrences, and, if possible, to determine the 

source of the uranium and the time of its deposition.

LITERATURE CITED

Frondel, J. W., and Fleischer, Michael, 1952, A 

glossary of uranium- and thorium-bearing minerals, 

2d ed.: U. S. Geol. Survey Circ. 194.

Genth, F. A., 1875, Preliminary report on 

the mineralogy of Pennsylvania: Pa. Geol. 

Survey, 2d, B., p. 144.

Lesley, J. P., 1885, A geological hand atlas 

of the sixty-seven counties of Pennsylvania: 

Pa. Geol. Survey, p. 33-34.

Weir, D. B., 1952, Geological guides to prospecting for carnotite deposits on the Colorado 

Plateau: U. S. Geol. Survey Bull. 988-B.

Wherry, E. T., 1912, A new occurrence of 

carnotite: Am. Jour. Sci., 4th ser., v. 33, 

no. 198, p. 574-580.

Willard, Bradford, 1939, The Devonian of 

Pennsylvania: Pa. Geol. Survey, 4th Ser., 

Bull. 19G, 481 p.

Winslow, Arthur, 1887, The Lehigh River section: Pa. Geol. Survey Ann. Rept., pt. 4, 

p. 1347-1385.

UNPUBLISHED REPORT

McKeown, F. A., 1949, Preliminary report of 

uranium deposits near Mauch Chunk, Pennsylvania: 

U. S. Geol. Survey Trace Elements Memo. 

Rept. 19.

INT.-DOT. SEC., HASH., D.C.69M29