Geological Survey

UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY METALLIC MINERAL DEPOSITS OF SOUTHEASTERN ALASKA BY Henry C. Berg, John E. Decker, and Beth S. Abramson U .S . GEOLOGICAL SURVEY OPEN-FILE REPORT 81-122 This report is preliminary and has not been reviewed for con- formi ty with Geological Survey edi toria1 standards Menlo Park, Cat ifornia 1981 CONTENTS Page Introduction ............................................................ ii Explanation ............................................................ iv Table headings .................................................. iv Abbreviations used ................................................. viji Descriptions of metallic and selected nonmetallic mineral deposits in southeastern Alaska ................................................ 1 Bradfield Canal quadrangle ......................................... 1 Craig quadrangle ................................................... 12 Dixon Entrance quadrangle ......................................... 37 Juneau quadrangle .................................................. 41 Ketchikan quadrangle.............................................. 59 Mt. Fairweather quadrangle ........................................ 71 Petersburg quadrangle .............................................. 86 Port Alexander quadrangle ......................................... 93 Prince Rupert quadrangle ........................................... 96 Sitka quadrangle ................................................... 98 Skagway quadrangle ................................................. 111 Sumdurn quadrangle .................................................. 120 Taku River quadrangle ............................................ 126 Yakutat quadrangle ................................................. 127 References .............................................................. 128 METALLIC MINERAL DEPOSITS OF SOUTHEASTERN ALASKA By Henry C. Berg, John E. Decker, and Beth S. Abramson INTRODUCTION This table and accompanying map briefly describe the metallic and certain nonmetallic mineral deposits publically known in southeastern Alaska in 1980. This report is part of a regional metallogenic analysis and mineral resource assessment of southeastern Alaska. Its purpose is to provide a background of current and historic mineral deposit data that ultimately will be integrated with other geological data to produce a metallogenic map and the resource assessment. This report is based on an extensive literature search, consultations with colleagues, recent field examinations 'by U.S. Geological Survey (U.S.G.S.) geologists, and information from private mineral exploration companies and consultants that has been made public. We also used U.S. Bureau of Mines (U.S.B.M.) maps depicting locations of mining claims. We brought the U.S.G.S. and U.S.B.M. data up to date where possible with information from other public sources; even so, there are large disparities in our information about the deposits, which ranges from well-documented reports of modern studies to vague descriptions in the old literature. We have made no attempt to evalu- ate the size, grade, or economic value of the deposits. However, some indi- cation of their significance can be inferred from the table. A future report will provide a geological assessment of the area's mineral endowment and its potential mineral resources. In this report, "southeastern Alaska" comprises the Alaska panhandle from the Gulf of Alaska to the U.S.-Canada boundary between latitudes 54'30' and 60°00' North. The deposits are, numerically tabulated within their respective 1:250,000-scale quadrangles, which are listed in the following 0 alphabetic sequence (see index map for locations) : Bradfield Canal, Craig, Oixon Entrance, Juneau, Ketchi kan, Mt. Fai rweather, Petersburg, Port A1 ex- ander, Prince Rupert, Sitka, Skagway, Sumdum, Taku River, and Yakutat. ACKNOWLEDGEMENTS We thank our U.S. Geological Survey colleagues Edward H. Cobb for painstakingly reviewing and correcting the entire report; Donald Grybeck and Edward M. MacKevett, Jr. for contributing to the descriptions of several newly discovered or otherwise key mineral deposits; and Mary J. Malloy, Cynthia A. Maley, and Carl Schwab for their outstanding work in preparing the report for pub1 ication. iii EXPLANATION TABLE HEADINGS MAP NO. AND NAME(S) (if known) Map no. refers to a specific deposit in a given quadrangle on the mineral deposits map and serves to link the map and table. Name(s) of mines or prospects are derived from published sources or from general usage. In some cases more than one mine or prospect are grouped under the same map number. Names in parentheses are alternate and generally less valid names for the mine or prospect preceding the parentheses. MAP COORDINATES, LOCAT ION For most deposits, location is given in latitude and longitude to the nearest minute. Locations of some deposits recently examined by U.S.G.S. geologists are given to the nearest second. The locations of many of the deposits described in the early literature are only vaguely known; coordinates for these deposits are followed by the notation "location approx." Early information about the locations of a few deposits listed in the table is so scanty that we could not plot them on the map. A few deposits whose positions were copied from generalized maps released by private mining interests were plotted on the map but we did not list their coordinates. CATEGORY refers to the classification of the deposit by conventional termi- nology. The terms mine, prospect, claim, and occurrence are used as fol 1ows : M--Mine: a mineral deposit with recorded production. In some cases, ore may have been mined, but not necessarily shipped. Claims may or may not be active, P--Prospect: a deposit that has been staked and, in most cases, has been scantily explored, but lacks evidence of production. .Probably some of the gold deposits that are listed as prospects have had at least meager production, but because of lack of substantive evidence they are classified as prospects. Claims may or may not be active. C--Claim: a lode or placer deposit for which the only available information consists of a claim reported on U.S. Bureau of Mines claim maps. According to Bureau of Mines usage, the term "lode" refers to any form of mineral deposit other than a placer deposit. 0--Occurrence: a deposit that may or may not be claimed, and is mainly known from published early reports, from recent U.S. Geological Survey, Alaska Division of Geological and Geophysical Surveys, or U.S. Bureau of Mines investigations, or from re1 iable but otherwise unconfirmed reports released by certain private mining interests. Numerous occurrences apparently only of pyrite are not included in the map and table, nor are unevaluated or unchecked occurrences of apparently anomalous metals in rock geochemical samples. FORM OF DEPOSIT denotes the physical aspect of a deposit, whether, for ex- ample, it consists of a vein, disseminated mineral grains, or masses e of minerals. The terms used under this heading are as descriptive as possible, and are distinct from genetic terms such as "porphyry" or "vol canogeni c" , whi ch imply origin or history of deposi t . When appro- priate, such genetic classifications of mineral deposits and other interpretive information appear in the column headed "Brief description". Because mineral deposits generally are geologically complex, a mine or prospect may contain more than one form of deposit; in addition, certain forms of deposits may be gradational. The following terms describing forms of deposits are used in this report: Lode or placer--U.S. Bureau of Mines claim maps classify mineral occurrences only as lode or placer deposits, without further information about form of deposit Vein--single or multiple veins of quartz, carbonate, or other gangue minerals containing varying amounts of metallic minerals; also veins of potentially valuable nonmetallic ore minerals such as asbestos and barite. Under this heading, the term vein includes deposits described as individual veins, and as veinlets, stringers, stockworks, fissure veins, breccia lodes, fracture fillings , gash veins, joint facings, and mineralized shear zones Disseminated--deposits in which potentially valuable minerals occur as individual particles, or as minute veinlets or clusters more or less evenly'distributed in the hostrock Massi ve--sol id masses of potentially valuable minerals in any form, including veins, beds, lenses, etc., essentially free of barren rock or of gangue minerals such as quartz or carbonate. Does not include "shoots" in quartz veins Stratiform (also bed or bedded)--a deposit having the form of a stratum or layer. In this report, we use the term stratiform in an objective sense, to describe the form of a deposit. We use the term stratabound in an interpretive sense, to imply a syngenetic origin for a deposit originally confined to (but not necessarily forming) a stratum, and re- gardless of any subsequent metamorphic or hydrothermal mobiliza- tion, concentration, or redistribution. The term stratabound thus appears only in the column that describes or interprets the geology of the deposits (headed "Brief description") Float--l.oose or scattered rock or mineral material whose bedrock source may or may not be known Stain--discoloration on the surface of an outcrop or lode caused by weathering, oxidation, leaching, or hydrothermal alteration. Stains most common1 y are rust-col ored ("iron-stain") due to

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