Preliminary summary review of thorium-bearing mineral occurrences in Alaska
Thorium-bearing minerals are known at 47 localities in Alaska. At these localities the thorium occurs as a major constituent or in minor amounts as an…
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PRELIMINARY S U M_M A R Y REVIEW 0 F T H 0 R I U M - B E A R I N G M I N E R A L 0 C C U R R E N C E S I N A L A S K A Trace Elements Hemorandurn Report UNITED STATES DEPARTMENT OF THE INTERIOR
Geological Survey "') (
UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY WASHINGTON 25, D. C. Dr o Phillip Lo Merritt~ Assistant Director Division of Raw Materials Uo s. Atomic Energy Commission Po 0. Box 30~ Ansonia Station New York 23, New York D:e a.:r Phil g IN REPLY REFER TO: Transmitted herewith for your information and distribution are six copies of Trace Elements Memorandum Report 339, "Preliminary summary revi0w of thorium~bearing mineral occurrences in Alaska 11 , by Robert Bates and Helmuth Wedow~ Jro, March 1952o It is concluded from the information compiled for this report that none of the known A~askan occurrences of thorium=bearing minerals have commorc:ial possibilities for thorium alo:ne o However, it is possibJe that thorium might be recovered economically as a byproduct of gold or tin placer mining in several areas, but more information on concentration ratios, thorium content and the economic situation is needed Beyond continuing the compilation of available information on thorium as it develops through the routine study of radioactive rra,terials~ the Survey plans no direct work on Alaskan +.horium occurrences in the near future e Additional information on the thorium content of the radioactive veins in the vicinity of Salmon Bay in southeastern Alaska will become available as a result of general reconnaissance for uranium in the northern part of Prince of Wales Island during the summer of 1952o We plan to publish this report as a Geological Survey circular~ and are asking Mro Hosted 9 by a copy of this letter~ whether the Commission has any objection to such publication Sincerely yours,
,JII UNCLASSIFIED Geology Mineralogy This document consists of 28 pages, plus 1 figure Series A UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PRELIMINARY SUMMARY REVIEW OF THORIUM-BEARING MINERAL CCC URRENCES IN ALASKA* By Robert Go ~tes and Helmuth Wedow~ Jro March 1952 Trace Elements Memorandum Report 339 This preli~inary report is distributed without editorial and technical. review for conformity with official standards and no~ menclatureo It is not £or pub~ lie inspection or guotationo jUL 1 3 1983 *This report concerns work done on behalf of the Division of Raw Materials of the Uo So Atomic Energy Commission
!' Distribution ~Series A) USGS TEM Report 339 GEOLOGY MINERALOGY No. of copies American Cyanamid Company, Watertown o Argonne National Laboratory o o o o o o o o Atomic Energy Commission, Washington o Carbide and Caxbon Chemicals Company, Y=l2 Area Colorado Raw Materials Office (To Wo o o Division of Raw Materials, Denvero o o o o o o Division of Raw Materials, New York o o Division of Raw Materials~ Spokane o o o Division of Raw Materials~ Washington Dow Chemical Company~ Pittsburg o o o o Technical Information Service~ Oak Ridge Terro Depto Mines 9 Juneau {Lo H. Sa.area). Terro Dept. Mines~ Ketchikan (Ao Eo Glover) o Terro Depto Mines, Anchorage {Po o. Sandvik) Terr. Dept. Mines, ;·College (D. J. Cook) Terro Dept. Mines~ Nome (Do Jones) Uo So Bureau of Mines 9 Bluemont 000000006 0 '1 Uo So Geological Surveyg Mineral Deposits Branch 51 Washington o o o o o
Geochemistry and Petrology Branch, Washington Geophysics Branch~ Washington o
o o o
o Alaskan Section, Washington
o
o Vo Eo McKelvey~ Washington o o o o
o o o L o R o Page Denver o o o o o o o o o o o o o o Ro Po Fischer~ Grand .Junction o o o o o A. Eo Weissenborn~ Spokane o o o W. Co Overstreet, Shelby o o o o ., o Go Oo Gates, San Francisco o o . o o Wo So Twenhofel, Juneau o o o o o o o o o o Ro Mo ·chapman$' Fairbanks TE~0 51 Washington . o o o o o o (Including master)
CONTENTS Abstract o o o o e~o Introduction G G ft ., Discussion of data o o o o o ., o o o o Thorium=bearing minerals o o o o o Thorium occurrences of particular note Salmon Bay area o o o o o o Tobin Creek=Big Creek area Manley Hot Springs district o o Eureka area Tofty tin be1t o o o o o Hot Springs Dome area o o o Long area o o o o o o o o o o o o Nixon Fork area o o o o o Buckland-Kiwalik district o Clem Mountain area o o
0, Hunter Creek=Connolly Creek=Fairhaven Creek area o o o ., o o o o o o o
o o Granite Mountain area o o o G ., ., o Darby Mountains district., o Tubutulik River area o o o Golovin Bay area o o Cape _Mountain area o o Conclusions'' o References Table lo 0000 00000 .TABLES General description of thorium~bearing minerals belonging to species that are found i.n Alaska Page 2o Occurre~ces of thoriwn..,bearing minerals in Alaska o ILLUSTRATION Figure lo Map of Alaska showing locations of thorium occurrences o o o o o ., o o o o o 0 In envelope
PRELIMINARY SUMMARY REVIEW OF THORIUM=BEARING Mimm,AL OCCURRENCES IN ALASKA By Robert G. Bates and Helmuth Wedow, Jr. ABSTRACT Thorium-bearing minerals are known at 47 localities in Alaska. At these localities the thorium occurs as a major constituent or in minor amounts as an impurity in one or more of the following 12 minerals g allanite, columbite, ellsworthit~, eschynite, gummite, monazite 9 orangite, parisite, thorian~te, thorite, xenotime 1 and zircon. In addition other minerals, such as biotite and sphene, are radioactive and contain thoriumo Sev~ral unidentified columbate minerals with uranium or thorium and uranium as major constituents have been recognized at some localities. The distribution, by type of deposit, of the 47 thoritim occurrences is as follows lode 3, lode and placer - granitic rock 3, granitic rock and related placer - 14, and placer - 26. Of the four iode occurrences only the radioa~tive veins at Salmon Bay in southeastern Alaska anq the contact metamorphic deposit in the Nixon Fork area of central Alaska ~arrant !! further consideration, although insufficient data are available to deter~ mine whether th~se two deposits have commercial possibilities. The remaining occurrences of thorium=bearing minerals in Alaska are limited to placer deposits and disseminations of accessory minerals in gr&nitic rocks. In most of these occurrences the thorium=bearing miner~ls occur in only trace amounts and consequently warrant little further cons~derationo More data are needed to determine ·the possibilities of byproduct recovery of thorium-bearing minerals from several of the gol~ and tin placerso
IN'l'RODUCTION Prior to the initiation of the Geological Surveyis Trace Elements program in 1944~ little was known about the occurrence of thorium~qearing minerals in Alaskao Mertie (1925~ Po 260) reported th~ presence of monazite in the placers of Big Creek in the Chandalar district north of Fort Yukono Eschynite~ xenotime~ and monazite were identified in the tin~bearing placers of the Manley Hot Springs district west of Fairbanks (Mertie and Waters~ 1934~ PPo 229~ 239~ During World War II Jo Ho Skidmore (19.44) reported to the Union Mines Development Corporation on the radioactivity of various Alaskan placers, noting that concentrates from mining operations on Sweepstakes Creek in the eastern Seward Peninsula were especially radio"" active Later work (Gault et alo, 1946; Killeen and ~ite, 1950) by the Geological Survey found that the chief radioactive mineral in the concentrates from Sweepstakes Creek and other nearby streams is uranothorianiteo Considerable information has been accumulated on the occurrence of thorium=bearing minerals:··during the course of the Geological Survey 9s
reconnaissance investigations for uranium in .Alaska o All available data on thorium=bearing minerals in_Alaska are now being compiled~ and the purpos~ of this report is to present preliminary summary of the data compiled to date o The spectrographic and chemical analyses, most of the radiometric analyses and mineral identifications used in this report were made in the Geological Surveyvs Trace Elements Section Washington Laboratory; a few of the radiometric analyses and mineral identifications were done by member~:. of the Survey 9s Alaskan Trace Elements Unito This work was done·on behalfof the Division of Raw Materials of the Uo So Atomic Energy Commissiono
DISCUSSION OF DATA Thoriu.in..,.beari.ng minerals Twelve minerals containing thorium 1 either as a major constituent or in minor amounts as an impurity~ are known in Alaskao These minerals are allanite~ columbite ellsworthite eschynite ') .. · gummite monazite~ orangite parisite thorianite, thorite xenotime $) and zircono For the co~venience . of the reader brief general descriptionsof these minerals~ summarized from Ford (1932)~ Frondel and Fleischer (1950)~ George (1949), and Palache~ et alo (1951) are given in table lo It should be emphasized that these mineral descriptions~ particularly the thorium percentages, refer to mineral occurrences outside of Alaska, very few data are available on the thoripmbearing minerals in Alaska beyond the fact that their presence at a particular locality has been noted In additionS~ other minerals, such as biotite ~nd sphene, are radioactive and may contain thoriumo Several unidentified columbate minerals with uranium or thorium and uranium as major constituents have been recognized at some localities Thorium occurrences of particular note Thorium is known to be present because of the identification~ of thoriumbearing minerals, or assumed to be present because of disco~panic~s bet~een ' ' equivalent uranium and uranium analyses~ at 47 localities in Alas~o ~rtinent data on these occurrences are given in table 2 at the end of the reporto The distribution of the 47 occurrences by type of deposit is as follows: lode lode and place~ .· granitic rock
granitic rock and placer placer only Thirteen of these localities are worthy of further study because samples from them have a relatively high thorium content 1 or because thorium=be~ring
minerals occur in more than trace amounts The distribution by type of de= post of these 13 localities is as follows& lode o o o o o o o o o o o o o o lode and placer o o o o o o o o 1 granitic rock and placer o o o o 5 placer o o o o o o o ooo o o o o 6 Summary descriptions of these 13 localities are given below Salmon Bay area In the Yicinity of Salmon Bay (noo 2, figo 1 and table 2) at the northern end of Prince of Wales Island, southeastern Alaska~ radioacti~ hematite~carbonate veins cut metamorphosed sedimentary rocks of S~luria~ age (Houston, 1951 PPo 69 9). Most of the veins are less than 5 inche~ wide but at one locality a vein 6 to 10 feet wide is exposed for about 300 feet o A sample from a to J ... inch vein contains Oo07 perce~t equivalent uranium,!) but only 0.00.3 percent uranium The difference is probably due to thoriumo In addition to the hematite and carbonates~ the veins contain small amounts of pyrit~ and locally minor amounts or traces of purple fluorite chalcedony feldspar .P and rnica.o Parisite (a fluocar ... bonate of the cerium metals) has been identified in samples from a_6- tp lOc:>foot thick vein {Houston, in preparation) o The radioactive elements i·' in these veins are thought to be substituting for iron in the he~tite or carbonates 9 or may also occur as impurities in the fluorite or parisiteo Tobin Creek=Big Creek area Placer concentrates from the Tobin C'reek""Eig Cree.k are~ {no o · 26~ fig.. 1 and table 2) of the Chandalar district on the south flank of the Brooks Range in northeastern Alaska contain as much as 15 percent monazite (White~ ., 1952) which is associated with variable amounts of hematite~ pyrite~ schee-
lite~ arsenopyrite~ galena~ chalcopyrite, and gold The maximUm ~quivalent uranium content of any of the placer concentrates so far obtained from the Chandalar district is Oo05 percent" The source of the monazite be "a highly acidic granitic rockll possibly of pegmatitic character'' (Martie, 1925 j) Po 263) o Manley Hot Springs district Eureka. areao In the Eureka area (no., 28 9 figo. 1 and table 2) of tpe Manley Hot Springs district in central Alaska 9 Moxham (in preparation) found monazite and radioactive zircon in granite at Elephant MoUQtaino This granite averages about 0~004 percent equivalent uranium Co:J;lcentrates from placers in the Eureka area contain from Oo004 to Oo042 percept equivalent uranium and average about Oo02 percent' equivalent uranium The ra~io activity is attributed mostly to thoriumj) as monazite constitutes up to 10 percent of the concentrates and is the chief radioactive mineral o The monazite in the Eureka placers was probably derived from the granite at Elephant Mountaino Tofty tin belt Concentrates from placers of the Tofty tin pelt {noo 2~ll figo 1 and table southwest of the Eureka area in the Manley Hot Springs districtj) contai~ monazite~ xenotimell columbite 1 eschynitell and radioactive zircon (Moxhamll in preparation)~~ A c9n.ce~tr~te from Idaho Gulch was found to contain as much as 2o3 percent equivalent uranium 9 although generally the radioactivity of the Tofty conce9trates is in the OoOX range of percent equivalent uranium., Moxham (in preparation~) indicates that the eschynite contains less than 1 percent thorium and no uranium the columbite has an equivalent uranium content of about Ool percent; the equivalent uranium content of the monazite does not exceed 1 percent; and the zircon averages about Oo07 percent equivalent uranium"
The bedrock source of the radioactive minerals in the Tofty concentrates has not been discovered, ·but may be a differentiate phase of the intrusive at Rough Top Mountain to the north or the granite at Hot Springs Dome to the south or both (.IVErtie and Waters, 1934~ PPo 244=246) o Hot Springs Dome areao-~In the Hot Springs Dome area (noo 301 figo 1 and table 2) monazite and xenotime are found in most of the_ placers of creeks draining the granite area of Hot Springs Dome (Moxham-9 in preparation) o The equivalent uranium content of this granite averages 0.003 percent. Although the radioactivity of the heavy~mineral fractions (those greater than 3o3 specific gravity) of the placer concentrates from the ijot Springs Dome area is in the OoOX range of percent equivalent uranium, one concentrate from a tributary of Hot Springs Slough on the south side of the Dome contains 0.3 percent equivalent uranium and about 20 percent monazite and 5 percent xenotimeo Another concentrate from glacial materia~ just east of Blowback Creek on the north side of Hot Springs Dome contains 0.155 per~ cent equivalent uranium and about 20 percent monazite. Long area In the Long area (noo 31, figo 1 and table 2) of the Ruby-Poarman district in central Alaska, allanite and thorite are the chief radioactive minerals found in granite and in placers derived from the granite (White and Stevens, in preparation-b). T~e equivalent uranium content of the granite averages 0.005 percent; heavy=mineral fractions (those gr~ater than 2o8 ~pacific gravity) of the placer concentrates contain as much a·s 1.6 percent equivalent uranium and average Oo3 percent equivalent uranium The thorite content of the heavy=mineral fractions from both the granite and placer concentrates ranges from a trace to about 10 percent.
Qualitative spectrographic analysis of the thorite indicates urani~(?), thorium 9 and silicon as major constituents, and calcium, iron, titanium~ and yttrium as minor constituents Chemical analysis of the thor;te shows the uranium content to be about 8 percent. No analytical data are available on the allanite except that it gives a positive flux test for uranium Nixon Fork area Uranium-bearing thor~anite, allanite, and other radioactive ~nerals have been reported from the Nixon Fork area (noo 33, figo 1 and table 2). in central Alaska (White and Stevens, in The th~ianite occurs in placers, where it is associated with uraniferous hematite, mala= chite, sphene, and zir~ono The concentrate exhibiting the greatest radio- ' activity contains Oo078 percent equivalent uranium, most of which is attributed to the uraniferous thorianite o The bedrock source of the r~dioactive minerals has not been located Large fragments of an altered limestone on the dump of the wqalen mine contain a high .percentage of r~dioactive allanite o The altered l~mestone is apparently closely associated with contact=metamorphic gold=copper ores along a limestone-monzonite contact The altered limestone contains as much as Oo05 percent equivalent uranium, which is ascribed to thorium, as chemical analyses show a content of only Oo004 percent uranium About a quarter of the altered limestone consists of minerals of greater than 2o8 specific gravity or this heavy fraction 98 percent is allanite; zircon, ~anite, and scheelite constitute the remaining 2 percent Near the shaft of the ~alen mine a.highly altered phase of the limestone is exposed containing about Oo025 percent equivalent uranium and Oo002 per~ cent uranium The radioactive mineral here is parisite, which in the s~mples
taken makes up about 95 percent of the heavy-mineral fraction (that greater than 2o8 specific gravity) of the rocko Buckland-Kiwalik district ~lem Mountain areao=~Uranothorianite and traces of thorite have been identified in several placer concentrates from the Clem Mountain ~ea (noo 36~ fig. 1 and table 2) in the northern part of the Buckland-Kiwali~ district (West and Matzke~ in preparation) of the eastern Seward Peninsulao Heavy~mineral fractions (those greater than 2.8 specific gravity) containing more than Oo025 percent equivalent uranium were obtaine~ fro~ concentrates of placers in Duck~ East Clem~ and West Clem Creekso The heavy-mineral fraction with the greatest radioactivity (Ool06 percent equi.valent uranium) was obtained on Duck Creek above the mouth of West Clem Although the source of the radioactive minerals is not known, it is likely that they are disseminated accessory minerals in the granitic intrusives that form the backbone of the Buckland-Kiwalik divide, as the radioactive minerals are found only in the creek gravels containing granitic pebbles Hunter Creek~Connolly Creek-Fairhaven Creek area.~~Placer from creek gravels within the headwater drainage of Hunter, Connolly, and Fairhaven Creeks (noo 37, figo 1 and table 2) 9 south of the Clem Mountain area 9 contain thorite~ uranothorianite, gummite~ and traces of arapgite (West and Matzko, in Concentrates w~th heavy-mineral fractions containing more than Oo025 percent equivalent uranium were obtaine~ from numerous sites in the Hunter Creek~Connolly Creek=Fairhaven Creek areao The sample with the greatest radioactivity was taken on Muck Creek, a left~limit
tributary of Hunter Creek~ and contains Ool6 percent equivalent ur~niumo The bedrock source of the radioa~tive minerals is not certain, but, as in the Clem Mountain area~ is presumed to be the granitic rocks in the drainage basins of the streams with radioactive placerso The thorite apd orangite appear to be restricted to the gravels in the headwaters of Fairhaven Cr~ek, and the uranothorianite and gummite appear to be limited to placer~ in t~e headwaters of Hunter and Connolly Creekso Grauite Mountain areao~~Granite Mountain (noo 38, figo 1 and table 2) in the eastern Seward Peninsula is composed largely of a syenitic stock 'hich was intruded into a complex of andesitic flows and intrusives (Gault, et al., 1946~ Killeen and White~ 1950~ West and Matzko~ in The average radioactivity of the syenite is about 4 times that of the andesitic rocks The chief radioactive minerals in placer and bedrock samples from the Granite Mountain area are allanite~ uranothor~anite, thorite, and gummiteo The equivalent uranium content of the heavy=mineral fractions (those greater than 2o8 specific gravity) of the placer concentrates is generally OoOX percent Concentrates with more than Oo025 percent equivalent ur~nium h~ve been obtained from the placers of headwater tributaries of the Pe~ce River, Anzac Creek~ Rube Creek, Sweepstakes Creek~ headwater tributaries of the Kiwalik River 9 the South Fork of Quartz Creek, Cub Creek, and an ~named tributary of the West Fork of the Buckland Rivero In all the radioactive concentrates the uranothorianite appears to be the main radioactive mineral. Although allanite is relatively abundant in a pegmatitic facies of the granitic rock near the top of Granite Mountain, and traces of uranothorianite have been identified among the accessory minerals of a specimen of syenite from the north flank of Granite Mountain in the headwaters of ~uartz Creek no lode concentrations of the radioactive minerals have yet been found
However 9 several placer concentrates from the extreme headwaters of the Peace River on the east flank of Granite Mountain near the andesite-syenite contacts have an equivalent uranium content of about Oo2 to about Oo8 percent or approximately 10 times that of the average uranothorianite=bearin~ concan~ trates found elsewhere in the eastern Seward Peninsulao These more radioactive concentrates contain a higher content of the radioactive m~nerals, particularly uranothorianite 9 than the other radioactive concentr~tes; in addition they contain copper sulfide minerals 9 silver, and bismuth, which have not been identified in the average uranothorianite-b.earing samples The greater amount of uranothorianite and the occurrence of minerals believed to be of hydrothermal origin in placers less th~n a mile from stream divides suggest the presence of a lode containing radioactive mineralso Darby Mountains district Tubutulik River areao~=The chief radioactive minerals found !n the placers of the Tubutulik River area (noo 4.0~ figo 1 and table 2),in the northeastern part of the Darby Mountains district in the eastern Seward Peninsula~ are allanite and unidentified columbate minerals (West, in The heavy=mineral fractions (those greater than 2o8 specific gravity) of the concentrates contain as much as Ool percent equivalent uranium, but average.only about Oo02 percent equivalent uranium In three samples from the area the columbates are estimated to constitute fro~ 5 to 10 percent of the heavy=mineral fractions of the concent~ateso spectrographic analyses show that in two samples the columbates contain uranium as a major element with no thorium recognized' in the third sample the columbate contains both uranium and thorium as major constituents A spectro-
graphic analysis of the allanite in one sample shows thorium as a major constituent with no uranium found The bedrock source of the allapite is unknown, but is assumed to be differentiate phases of granitic rock in tpe drainage areas of the streams from which the samples were obt~inedo The presence of topaz and traces of cassiterite along with the columbates suggests that these minerals may be genetically related to lode tin occurrences It is also possible that these minerals may have originated in pegmatiteso Golovin Bay areao--The most radioactive minerals.in various types of placers along the east shor~. of Golovin Bay .(no. 42~ figo 1 and table in the western part of the Darby Mountains district~ are allanite, monazite, and an unidentified columbate mineral (West~ in The equivalent uranium content of the heavy~mineral fractions (those greater than 2.8 specific gravity) of concentrates from these placers ranges from OoOOl to about Oo08 percent The columbate mineral has been recognized only in a concentrate from slopewash on the beach about midway between Cheenik and Mission Creeks. The sample location is near .the contact of a younger granite with an old~r intrusive complex. The heavy~mineral fraction of this concentrate has ap equivalent uranium content of about Oo08 percent and is the most r~dioactive heavy~mineral fraction taken in the areao It is estimated that the unid~ntified columbate mineral comprises about 5 to 10 percent of the heavy-mineral fraction~ which also contains minor amounts of sphene!) topazl' hem~tite, allanite~ and scheelite. Qualitative spectrographic analysis of the columbate shows uranium and thorium as major constituents Farther south along the Golovin Bay coast monazite and trace·s of allanite are found in a slopewash concentrate of which t~e heavy~mineral fraction contains about Oo05 percent equivalent uranityn( ~This sample was taken near // the contact of granite with an older intrusive complex
The remaining radioactive concentrates from the Golovin Bay ~rea, have equivalent uranium contents that range from about OoOl to about Oo03 per~ cento This radioactivity is ascribed largely to traces of uranium or thorium in minor amounts of allanite 9 sphene, and zircono Cape Mountain area The major radioactive In:inerals in placer concentrates from the C:ape Mountain area (noo 47~ figo 1 and table .2)~ in the western Seward Peninsula~ are monazite~ xenotime~ and zircono The concentrates contain as much as Oo9 percent equivalent uranium and average about Oo03 percent equivalent uranium which~ because of the monazite content of the concentrate~, is ascribed mostly to thoriumo The source of the radioactive minerals is probably the granite at Cape Mountain~ although they may be genetically related to the tin mineralization in the areao CONCLUSIONS At 47 localities in Alaska thorium occurs as. a major constit~nt or in minor amounts as an impurity in one or several of 12 minerals. These minerals are allanite~ columbite, ellsworthite~ eschynite~ gummite~ monazite, orangite 9 parisite, thorianite~ thorite, xenotime, and zircono At some localities sphene and biotite are also radioactive and may contain thorium; unidentified columbate minerals with uranium or thorium and urani~ as major constituents have also been recognized Lode thorium occurr~nces warranting further consideration ares 1) in radioactive hematite=carbonate veins in the Salmon Bay area on Prince of Wales Island, southeastern Alaska, and 2) in a limestone=monzonite contact zone in the Nixon Fork area in central Alaskao
, Data on these two deposits~ however, are not sufficient to determine th~ir potentialities o The remaining thorium occurrences of any significance are in placers or as accessory minerals in granitic rocks It is possible that tporium might be obtained as a byproduct from gold or tin placer operatio~s in the following localities Locality 1) Tobin Creek~Big Creek area, Chandalar district, northeastern Alaska 2) Manley Hot Springs district, central Alaska 3) Long· area 9 central Alaska 4) Nixon Fork area, central . Alaska 5) Buckland~Kiwalik district, · west-central Alaska (Seward Peninsula) 6) Cape Mountain area, west~central Alaska (Seward Peninsula) Major thorium-bearing minerals Monazite Columbite Ellsworthite Eschynite Monazite Xenotime Thorite Uranothoriani te Uranothorianite Thorite Monazite Xenotime More data are needed~ however~ to determine the thorium potentialities of these placer localities.
Table l.~=General description of thorium=bearing minerals belonging to 1pecies that foun~ Alaska~ Mineral Allanite Chemical composition Hydrous silicate of aluminum~ calcium and the cerium metals Columbite Columbate of iron and mangane~e Ellsworthite Complex hydrous oxides· of columbium, tantalumg sodium, calcium~·with hydroxyl and fluorine; may contain up to 17 percent uranium Thorium (percent) ,. . . Up to 3 o.x Oo5 Eschynite Complex oxide or· columbium; 10 15 Gummite _tantalum 51 arid the rare earths with varying amounts of thorium and uranium Uranium with minor amounts·or · thorium, lead, and hydroxyl· Up to 22 D_e scription Colorg brown to black- ··· Luster~ resinous to submetallic FractUre: uneven t·a stibconchoidal Uabitg ·tabtilarg also.long and slender also massive Colorg black, grayish= brownish=black Lusterg submetallic to·sub=resinous FractUre: subconchoidal:to uneven Uabitg.short prismatic grains ~~cific.gravity: 5.2 7o9 Colorg amber=yeliow to dark brown Lusterg· adamantine · Fractiu-e g subconchoidal to .. slintery 9 uneven Habit8'rotirided grains, also massive Specific=gravity 3.8 4o2 ·- . "' Colorg broWnish~yellow to ·black Lusterg submetallic-to resinous, nearly dull :Fractlu;e g ·-small conchoidal_ ~abit3 m9stlY. also prismatic ~peciric gr~vityg 4.9 "" 5.2_ color orange, yellow, orange-yellow ~uste:r; i. dull ·to greasy · - Fract~e lineven to--·subconchoidal ~abit~ ~ssive, dense also in rounded or flattened , -· masses or crusts·· Specific gravity 3.9 - 6.4
;;. "'" Table lo~~General description of thorium~bearing minerals belonging to species that are found in Alaska (co~tinued) Mineral Monazite Orangite Chemical composition Rare-earth phosphate with some thoria and silica Thorium silicatei a variety of thorite Parisite Fluocarbonate of calcium and .the cerium .group Thorianite Oxide of thorium and tn"anium Thorite Thorium silicate Thorium (percent) 1 11' 0
'l Description Co~or: yellowish~ or reddish-brown~ golden-yellow Lusterg resinous FractUre: conchoiaal t'o uneven-· Habit: ·small~ often fiattened grains dolor: bright arrange"or orange=yellow ~uste~& vitreous to g~ssy wpen ft-lsh? dull to
· greasy when altered Fracture: conchoidal !{a bit.: square prismatic crystals i sometimes massive · Specific gravity: 4ol e. 6o3 .
! Color: brownish=yellow i brown 9 wax yellow Luster: vitreous to res-inous FractUre~ subconchoidal to .. splinter:ry · Habitg·c~ystals small and slender~ pyramidal or : "prismatic Specific gravity: 4o4 Color: black~ brownish or grayish ~riste~: submetallic to dull=or greasy Fracture g uneven to subconchoidal Habitg ·cubic Colorg comm6rily' black1. brcivm·~- less commonly green Luster: vitreous to glassy when fresh~ dull to grea'sy when altered Fracture: conchoidal.· · · aabl~: square prismatic crystals~ aumatimes massive Spec~ic gravity: 4ol ... bo4
Table lo==General description of· thorium~bearing minerals belonging to species that are found in Alaska (continued) Mineral Xenotime Zircon Chemical composition Essentially yttrium phosphate Zirconium silicate~ usually with some ferric oxide and often some thorium and uranium Thorium (percent) r· Oo4 3o3 Usually low but up to lJol reported Description Colorg shades of brown 9 yellow~ green~ grayish
white~ pink --- Lusterg resinous to dull or earthy Fracture g uneven·-and splinty - Habit~ ·long or short· prismatic crystals Specific-gravity~ 4o5 4o6 Color~ various shades of redj brown~ and gray where thorium=bearing · Luster g usually·· dull or sub=resinous when thorium.,.
bearing Fracture: conchoidal Eabita p~ismaticj commonly long~ less commonly stout~ also massive Specific gravity& 3o6 4o7
Table 2.--0occurrences of thorium-bearing minerals in Alaska Note: Explanation of symbols used in table G: granitic rock L: lode deposit P: placer I~IF: heavy mineral fraction (usually greater than 2.8 specific gravity) Quadrangle references dre the new 1:250,000 Alaska Reconnaissance Series, most of which are available at least in proof copy G) G) c; REGION G) G) G) G) G) """ ""' G) E """ .,Q """ """ ca """ E 31: """ N
<ll Quadrangle co :I <ll
1!11 u u co Reference no. Uig. 1) and location Ul :I
ca G) <1: u I&J I&J ""
;.( N SOUTHEASTERN ALASKA Craig(?) Kasaan Peninsula(?) Petersburg Salmon Bay area, Prince xYof Wales Island Port Alexander Goddard Hot Springs area SOUTH-CENTRAL ALASKA Bering Glacier Yakataga area Anchorage Fishhook Creek-Archangel Creek area, Willow Creek mining district .!/ Allanite occurs in sample from contact copper-iron ore; location in doubt Y Parisite not known to be radioactive, study now in progress Y Thorium may be replacing iron in hematite or carbonates 1/ Radioactive hematite-carbonate veins §/ Two other minerals belonging to zircon group 2J Other minerals are crytolite Y Pegmatites G) u c Equivalent uranium content G) :I (percent); presence u u of thorium assumed L:0.094 xY d./ L: up to 0.07 GP to 0.016 xW p HMF: up to 0. 32, av. 0.044 L: av. 0.004 HMF:up to 2.93 av. 0.15
References Wed ow, et al, 1951, p. 63 llouston, 1951, p. 4, table 1 West and Benson, in preparation Moxham, 1952 Moxham and Nelson, 1952
Quadrangle Reference no. (fig. 1) and location SOUTH-CENTRAL ALASKA Tyonek Spurr area
Mount Roundbend and Red Hill Bars, Kahiltna River Talkeetna Shalon Bar, Kahiltna River Petersville area Cache Creek, near mouth of Dollar Creek Poorman Creek EAST-CE~~RAL ALASKA Tanacross Alaska Highwey, about 2 miles southeast of Northway Junction Alaska Highway, about 15-23 miles northwest of Northway Junction Mount Hayes Ober Creek Big Delta Harding Lake-Richardson area Eagle Atwater Bar, Mosquito Fork, South Fork, Fortymile River Mission Creek area Slate Creek area Copper Creek Charley River Coal Creek-Woodchopper Creek
ct ? ? Table 2.--occurrences of thorium-bearing minerals in Alaska
u
e .a
e
a lJ:
N
(Ii
.. :I (Ii
e u :I u e u (II :I e .. u u w w
Q., ;.( N p p p p p p G G p GP p GP GP p p (continued) Equivalent uranium content (percent); presence References of thorium assumed HMF: in 0. OX ranqe File data, prospector's samples Concentrates contai.n Harder and Reed, 1945, 0.083 percent thorium pp. 5, 17, appendix Concentrate contains do 0.044 percent thorium HMF: up to 0.064 Robinson, et al, 1946, pp. 22, 23, table 5 Concentrate contains Harder and Reed, 1945, 0.03 percent thorium pp. 5, 17 Concentrate contains Harder and Reed, 1945, 0.044 percent thorium pp. 5, 6, appendix
G: 0.004 Wedow and Matzko, 1947, pp. 31, 58 G: 0.004 Wedow and Matzko, 1947, PP· 31, 60 HMF: up to 0.011, Wedow and Matzko, 1947, av. 0.006 pp. 36, 63 G: 0.004 Wedow and 1947, HMF-P: up to 0.02 pp. 27, 55-57 up to 0.041 White, 1950 Wedow and Tolbert, in preparation-b G: up to 0.006, Wed ow, in preparation av. 0.004 HMF-P: up to about G: up to 0.005 Wedow and Tolbert, in HMF-P: up to 0.096 preparation-b HMF: 0.013 Wedow and Tolbert, in preparation-a t-IMF: 0.009 File data
Table 2.--occurrences of thorium-bearing minerals in Alaska (continued) C) C) C) u C) C) C) C) "' C) e C) REGION ,Q "" Equivalent E :t:
N
Pi "' "' ., e ., "' "' u C) uranium content Quadrangle u e ., "' u (percent); presence . References "' ., C) u Reference no. (fig. 1) and location <1: u lo.l lo.l ::; ""
N of thorium assumed EAST -CENTRAL ALASKA Circle ---rr.- Hot Springs, Portage, and p HMF: up to about White and Tolbert, 1952 Ketchum Creeks Nome Creek p mw: 0.012 Wedow and 1947, p. 19 Livengood Ruth Creek p mw: 0.010 Wedow and Matzko, 1947, p. 22, 23 N NORTHEASTERN ALASKA
Wiseman ~Gold Bench and/or Ironside ? Bar, South Fork, Koyukuk p mw; up to 0.027 White, 1952, p. 10, table 1 River Rye Creek p HMF: 0.014 White, 1952, p. 6, table 1 Chandalar Tobin Creek-Big Creek area p HMF: up to 0.05 White, 1952, pp. 10-13 Mer tie, 1925, pp. 260-263 Mount Michelson x!V Okpilak River J GP G: 0.007 White, 1951 HrlfF-G: up to 0.08, av. 0.052 ffifF-P: av. 0.026 CENTRAL ALASKA Tanana Eureka area GP G: 0.004 in preparation HMF -P: up to 0.042, av. 0.02 Totty tin belt p HrlfF: up to 2. 3, Moxham, in preparation but generally in Mertie and Waters, 1934, O.OX range pp. 238-241 Hot Springs Dome area GP G: 0.003 Moxham, in preparation HMF-P: up to 0.3, but generally in O.OX range W Major radioactive mineral is biotite; radioactivity mostly due to uranium
Table 2.--0eeurrences of thorium-bearing minerals in Alaska (continued) II) .. II) II) u II) II) C) REGION II) E II) .Q of'4 1:1 .. Equivalent E , N
IIJ ., IIJ e ., u uranium content Quadro11qle u E ., u (percent); presence r.references Reference no. (fig. 1) and locotion 1:1 II) u ct u 1&.1 1&.1 o. N of thorium assumed CENTRAL ALASKA Ruby Long areo GP G: 0.005 White and Stevens, in HMF-P: up to 1. 63, preparation-b ov. about 0.3 Solomon Creek p HMF: 0.056 do !\led fro
Nixon Fork orea p HMF: up to 0.078, Horder ond Reed, 1945, p. 5 av. 0.015 White and Stevens, in preparation-a do I).Q/ L: up to 0.05 ~bite and Stevens, in HMF: up to 0.14, preparation-a av. 0.04 N SOUTHWESTERN ALASKA w lditorod ~ulian Creek p HMF: 0.03 White and Killeen, 1950 Flat orea GP G: av. prob. 0.004 Harder and Reed, 1945, pp. 5, 19 tlllfF-P; up to 0. 1, Wbite and Killeen, in but generally in preparation O.OX range WEST-CENTRAL ALASKA (Seward Peninsula) Candle
Clem Mountain area, Buckland- p HP,fF: up to 0.1.06, West ond lllatzko, in Kiwolik district but generalJy in preparation o.ox_ range Hunter Creek-connolly Creek- p HMF: up to 0.16, but do Fairhaven Creek area r generally in O.OX range Granite area
xW G: pro b. av. about Goult, et ol, 1946 p Killeen ond White, 1950 H~fF-F: up to 0.076, West and Motzko, in but generally in preparation O.OX ronge !!/ Rodiooctive minerol belonging to spinel group lQ/ Contoct metomorphic zone between limestone ond monzonite !!/ Heovy minerol fractions containing more thon 0.2 percent equivalent uranium restricted to heodwoters of Pence River; other possible thorium-beoring minerol in Gronite Mountoin oreo is rodiooctive sphene
Table 2.--0occurrences of thorium-bearing minerals in Alaska (continued) Cl) .. Cl) Cl) Cl) Cl) Cl) Cl) Cl) REGION Cl) Cl) e e
N 1:11 IIJ Ouadrangle
IIJ e .-! .-! u e Reference no. (fig. 1) and location IIJ
Cl)
u w w l.!l :;! E-< E-<
WEST-cENTRAL ALASKA (Seward Peninsula) Bendele ben Candle Creek area Solomon xU!- Tubutulik River area Headwaters of Kwiniuk River Golovin Bay area Nome god Solomon Cape Nome area Bendeleben Serpentine Hot Springs area Teller Ear Mountain area Brooks Mountain area Cape Mountain area Spectrographic analysis shows thorium and no uranium W Three unidentified columbate minerals; two with uranium and no thorium, one with both thorium and uranium as major constituents !!/ Unidentified columbate mineral containing uranium and thorium as major constituents Cl) u c Cl) Equivalent uranium content u Cl)
(percent); u presence 'f"4 .. u of thorium assumed N p HMF: av. about 0.01 xW p HMF: up to 0.104, av. 0.02 p HMF: up to 0.039, av. 0.01 xW p HMF: up to 0.074, av. 0.01
GP HMF..:<;: up to 0.01"2, GP G: av. 0.008 HMF-P: up to 0.84 GP G: 0.002 HMF-P: up to 0. 26, av. 0.056 G G: 0.003 GP HMF: up to 0. 9, av. 0.03
References Gault, 1949 West, in preparation N
do do West and Matzko, 1950 Moxham and West, 1949 Harder and Reed, 1945, p. 12 Killeen and Ordway, 1946 White and West, 1952, p. 8 Harder and Reed, 1945, p. 9 Also file data 16!02
REFERENCES Ford 1 Wo Eo, 1932, Danaus textbook of mineralogyg John Wiley and Sons, Inco~ New York~ No Yo~ 4th edo~ 851 PPo Frondel~ Jo Wo 9 and Fleischer, Me~ 1950~ A glossary of uranium- and thorium~bearing minerals Uo So Geolo Survey Circular 74~ 20 PPo Gault, Ho Ro, 1949, Trace elements reconnaissance in the Candle Creek area, FairhaVen district~ Seward Peninsula~ Alaska& Uo So Geolo Survey Trace Elements Investigations Repto 4lo Gault~ Ho Ro, Black," R.o · F o and Lyons, J o Bo 1946!> Preliminary report on trace elements investigations in the Sweepstakes Creek area, Koyuk. district 9 Seward Peninsula 9 Alaskag Uo So Geolo Survey Trace Elemer).ts. Investigations Repto 25o George 9 DVArcy 9 1949~ Mineralogy of uraniurrFand thorium~beaPing minerals: Uo So Atomic Energy Commission RM0=563 9 198 PPo Harder~ Jo Oo~ and Reed~ Jo Co 9 1945~ Preliminary report on radioactivity of some Alaskan placer samples Uo So Geolo Survey Trace Elements Investigations Repto 6o Houston 9 Jo Ro, 1951~ Preliminary summary of reconnaissance far uranium in southeastern Alaska during 195lg Uo So Geolo Survey Trace Elements Memorandum Repto 32lo 9 in preparation9 Interim report& radioactive hematite-carbonate veins in the Salmon Bay area 9 Prince of Wales Island, south ... eastern Alaskag Uo So Geolo Survey Trace Elements Memorandum Repto, number not assigned9 title subject to change o Killeen~ Po Lo 9 and Ordway~ Ro Jo 9 19469 Trace elements investigations Ear Mountain 9 Sewar~ Peninsula 9 Alaskag Uo So Geolo Survey Trace Elements Investigations Repto 27o Killeen 9 Po Lo, and White~ Mo Go 9 1950 Trace elements reconnaissance on the South Fork of Quartz Creek~ northeastern Seward Peninsula, Alaska: Uo So Geolo Stirvey Trace Elements Investigations Repto 42, part 2o Martie~ Jo Bo, Jro, 1925 9 Geology and gold placers of the Chandalar district~ Alaskag U. So Geolo Survey Bull. 773~E 9 PPo 215=263o Mertie 9 Jo Bo~ Jros and Waters 9 Ao Eo 9 Jra.ll 1934, Mineral deposits of the Rampart and Hot Springs districts~ Alaska 9 by Jo Bo Mertie, Jro; Placer concentrates of the Rampart and Hot Springs districts, by Ao Eo Waters, Jro~ Uo So Geolo Survey Bullo 844~D~ PPo 163~246o
,
Moxham, Ro Mo~ 1952, Radioactive minerals in the Yakataga beach placers~ southern Alaskag Uo So Geolo Survey Trace Elements Memorand~ Repto 326e , in preparation9 Reconnaissance far radioactive deposits in the Manley Hot Springs=Rampart district~ Tanana quadrangle 1. central Alaska: Uo S. Geol. Survey Trace Elements Investigations Repto 54; title subject to change. Moxham~ R. Mo~ and Nelson 1 A. E. 1 1952, Radioactive pegmatite minerals in the Willow Creek mining district 9 south=central Alaskag Uo So Geolo Survey Trace Elements Investigations Repto 19lo Moxham, Ro M. 1 and West 1 Wo S. 9 1949, Trace elements investigations in the Serpentine=Kougarok area~ Seward Peninsula~ Alaskag Uo s. Geol. Survey Trace Elements Investigations Rept. 39o Palache~ Co, Berman Hop and Frondel 9 Co 9 19519 Danaus system of mineralogyg John Wiley and Sons 9 Inco 9 New York, No Yo 1 7th ·ede volo 2, 1124 PPo Robinson 9 Go Do 1 Wedow 9 Helmuth 9 Jro 9 and Lfons~ Jo Bo 9 1946, Trace elements investigations in the Cache Creek~uppe~.Peters Creek area 9 Yentna district 9 Alaska& Uo So Geolo Survey Trace Elements Investigations Rept. 26. Skidmore~ Jo Ho 9 1944~ Preliminary reconnaissance survey of Alaska placer deposits Union Mines and Development CorparationD unpublished report. Wedow~ Helmuth 9 Jro 9 in preparation 9 Reconnaissance for radioactive deposits in the Eagle=Nation area 9 Eagle and Charley River quadrangles 9 east~ central Alaskag Uo S. Geolo Su~vey Trace Elements Investigations Repto 56~ title subject to change. Wedow 9 Helmuth 9 Jro, and MatzkoD Jo J. 9 1947 9 Trace elements reconnaissance along highways in the Tanana and upper popper River valleys, Alaskag U. So Geol. Survey Trace Elements Investigations Repto 38. Wedow, Helmuth~ Jr., and Tolbert 9 Go Eo, in preparation=a, Radioactivity at the Copper Creek copper lode prospect, Eagle quadrangle, eastcentral Alaskag Ue S. Geolo Survey Trace Elements Investigations Rept. 195~ title subject to change. ' in preparation=b~ Reconnaissance for radioactive deposits in the Fortymile district~ Eagle quadrangle, east~central Alaskag Uo So Geolo Survey Trace Elements Investigations Repte 196; title subject to change Wedow~ Helmuth~ Jr.~ White, Mo G., and Moxham9 Ro Mo 9 1951~ Interim report on.an appraisal of the uranium possibilities of Alaskag U.S. Geolo Survey Trace Elements Memorandum Repto 235o
'Iii West, WG So, in preparation~ Reconnaissance for radioactive deposit~ in the Darby Mountains area, Solomon and Bendeleben ~uadrangles, Seward Peninsula, Alaska& U. So Geolo Survey Trace lements Investigations Repto 53; title subject to change West, Wo So, and Benson, Po Do 9 in preparation 9 Reconnaissance for radio~ active deposits in the vicinity of Ketchikan 9 Goddard Hot Springs, Chichagof~ Funter Bay, and Juneau~ southeastern Alaskag Ue So Geolo Survey Trace Elements Investigations Repto 1891 title subject to change West, Wo So 9 and ~tzko~ Jo Jo 9 1950~ Radiometric and mineralogic studies of the granitic complex in the Cape Nome area 9 Seward Peninsula~ Alaska~ Uo So Geolo Survey Trace Elements Investigations Repto , 45 SJ part 2o ' in preparation 9 Reconnaissance for radioactive deposits · in the Buckland=Kiwalik district, Candle quadrangle, Seward Peninsula, Alaska:; Uo S. Geol. Survey Trace Elements Investigations Repto 49; title subject to change White~ Mo G.~ 1950~ Radioactivity and mineralogy of placer concentrates. from the Fortymile district, Alaska g U o ·So Geol o Survey Trace Elements Investigations Repto 57<=Ao 1951D Radioactivity in the 110kpilak90 gneissic granite 9 Mount Michelson area 9 northeastern Alaska& Uo So Geolo Survey Trace Elements Investigations Repto 57=Co 1952 9 Radioactivity and mineralogy of placer concentrates from the Wiseman and Chandalar districts Upper Yukon region, Alaska: Uo So Geolo Survey Trace Elements Memorandum Repto 327o White 9 Mo Go 9 and KilleenD Po Lo, 1950p Radioactivity and mineralogy of. concentrates from the placers of Julian, Moore, and Candle Creeks, and the Cripple Creek Mountains 9 lower Yukon=Kuskokwim Highlands region~ Alaska& Uo So Geolo Survey Trace Elements Investigations Repto 45, part lo in preparation, Reconnaissance for radioactive deposits in the vicinity of Flat~ Iditarod quadrangle, southwestern A.laskag Uo S. Geolo Survey Trace Elements Investigations Repto 469 title subject to change . White~ Mo Go 9 and Stevens, J Me ll i.n prep aratlon=a, Reconnaissance for radioact:lve deposits in the vicinity of the Nixon Fork mines~ Medfra quadrangle, central Alaska~ Uo So Geolo Survey Trace Elements Investigations Repto 75~ title subject to change in preparation=b~ Reconnaissance for radioactive deposits in the Ruby=Poorman district~ Ruby quadrangle~ central Alaskag Uo So Geolo Survey Trace Elements Investigations Repto 192~ title subject to change
White~ M. G.~ and Tolbert, G. E., 1952, Radioactive granite in the Miller House-Circle Hot Springs area, east-central Alaskag U. S. Geol. Survey Trace Elements Investigations Rept. 194. White, M. G., and West, w. S., 1952, Preliminary summary of reconnaissance for uranium on the Seward Paninsula, Alaska, during 1951: U. s. Geol. Survey Trace Elements Memorandum Rept. 322