Significant Metalliferous Lode Deposits and Placer Districts of Alaska By WARREN j. NOKLEBERG, THOMAS K. BUNDTZEN, HENRY C. BERG, DAVID A. BREW, DONALD GRYBECK, MARK S. ROBINSON, THOMAS E. SMITH, and WARREN YEEND U.S. GEOLOGICAL SURVEY BULLETIN 1786 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1987 For sale by the Books and Open-File Reports Section U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225 Library of Congress Cataloging-in-Publication Data Significant metalliferous lode deposits and placer districts of Alaska. U.S. Geological Survey Bulletin 1786 Bibliography Supt. of Docs. No.: 119.3:1786 1. Placer deposits-Alaska. 2. Ore deposits-Alaska. I. Nokleberg, Warren j. II. Series. QE7S.B9 No. 1786 557.3 s 87--600165 [TN24.A4] [553' .13'09798] COVER Mill buildings at Kennecott, Alaska. The Kennecott district Cu-Ag mines in the Wrangell Mountains were some of the principal sources of copper in North America from 1913 to 1938. See deposit description for Kennecott district (number 30 for southern Alaska). Copyrighted drawing used by permission of Gail Niebrugge, artist, Glennallen, Alaska. PREFACE This report is a compilation of the signifi geology. The unpublished data were contributed cant metalliferous lode deposits and placer by mineral deposit and regional geologists in districts of Alaska, and is a comprehensive data private industry, universities, the U.S. Geo base for a companion article on the metallogene logical Survey, the Alaska Division of Geologi sis and major mineral deposits of Alaska that cal and Geophysical Surveys, the U.S. Bureau of will be published in the volume on Alaskan Mines, and the authors. Data were also obtained geology for the Decade of North American Geology for classification of metalliferous mineral (DNAG) by the Geological Society of America. deposits from mineral deposit geologists in the This report is based on recent unpublished data U.S. Geological Survey. The 54 contributors who on metalliferous mineral deposits of Alaska, and gave freely of their data, with affiliations at on recent and older published articles and sum the time of contribution, are: maries of Alaskan mineral deposits and regional Gary L. Andersen, Resource Associates of Alaska, Inc., Fairbanks, Alaska Roger P. Ashley, U.S. Geological Survey, Menlo Park, California James C. Barker, U.S. Bureau of Mines, Fairbanks, Alaska Joseph A. Briskey, U.S. Geological Survey, Menlo Park, California William P. Brosge, U.S. Geological Survey, Menlo Park, California P. Jeffery Burton, Jeffery Burton and Associates, Fairbanks, Alaska Robert M. Chapman, U.S. Geological Survey, Menlo Park, California Edward R. Chipp, Resource Associates of Alaska, Inc., Fairbanks, Alaska Dennis P. Cox, U.S. Geological Survey, Menlo Park, California Robert L. Detterman, U.S. Geological Survey, Menlo Park, California John T. Dillon, Alaska Division of Geological and Geophysical Surveys, Fairbanks, Alaska J. Dunbier, Noranda Exploration, Inc., Anchorage, Alaska Inyo F. Ellersieck- U.S. Geological Survey, Menlo Park, California Jeffrey Y. Foley, U.S. Bureau of Mines, Fairbanks, Alaska Peter F. Folger, Department of Geology, University of Montana, Missoula, Montana Helen L. Foster, U.S. Geological Survey, Menlo Park, California Curtis J. Freeman, The FE Company, Inc., Fairbanks, Alaska D. R. Gaard, Resource Associates of Alaska, Inc., Fairbanks, Alaska Bruce M. Gamble, U.S. Geological Survey, Anchorage, Alaska Wyatt G. Gilbert, Alaska Division of Geological and Geophysical Surveys, Juneau, Alaska Charles C. Hawley, Hawley Resource Group, Inc., Anchorage, Alaska Murray W. Hitzman, Chevron Resources Company, San Francisco, California Brian K. Jones, Bear Creek Mining, Kennecott Corporation, Anchorage, Alaska Ian M. Lange, Department of Geology, University of Montana, Missoula, Montana Christopher D. Maars, Anaconda Minerals Company, Anchorage, Alaska Edward M. MacKevett, Jr., 1230 Bayview Heights, Los Osos, California W. David Menzie, U.S. Geological Survey, Menlo Park, California Paul A. Metz, Mineral Industries Research Laboratory, University of Alaska, Fairbanks, Alaska J. S. Modene, Cominco Alaska, Inc., Anchorage, Alaska David W. Moore, Cominco Alaska, Inc., Anchorage, Alaska William Morgan, Duval Corporation, Anchorage, Alaska Clint R. Nauman, Research Associates of Alaska, Inc., Fairbanks, Alaska Steven W. Nelson, U.S. Geological Survey, Anchorage, Alaska Rainer J. Newberry, Geology/Geophysics Program, University of Alaska, Fairbanks, Alaska Steven R. Newkirk, Research Associates of Alaska, Inc., Fairbanks, Alaska Harold Noyes, Doyon, Limited, Fairbanks, Alaska William W. Patton, Jr., U.S. Geological Survey, Menlo Park, California Joseph T. Plahuta, Cominco Alaska, Inc., Anchorage, Alaska Ill Christopher C. Puchner, Anaconda Minerals Company, Anchorage, Alaska John Reed, Hawley Resource Group, Inc., Anchorage, Alaska Donald H. Ri~hter, U.S. Geological Survey, Denver, Colorado Robert K. Rogers, WGM, Inc., Anchorage, Alaska Charles M. Rubin, Anaconda Minerals Company, Denver, Colorado D. A. Scherkenbach, Noranda Exploration, Inc., Anchorage, Alaska Jeanine M. Schmidt, U.S. Geological Survey, Anchorage, Alaska P. R. Smith, U.S. Borax and Chemical Corporation, Spokane, Washington Carl I. Steefel, Anaconda Minerals Company, Anchorage, Alaska J. E. Stephens, U.S. Borax and Chemical Corporation, Spokane, Washington Richard C. Swainbank, Geoprize, Limited, Anchorage, Alaska Gregory Thurow, U.S. Bureau of Mines, Fairbanks, Alaska Alison B. Till, U.S. Geological Survey, Anchorage, Alaska J. Dean Warner, U.S. Bureau of Mines, Fairbanks, Alaska Frederic H. Wilson, U.S. Geological Survey, Anchorage, Alaska Loren E. Young, Cominco Alaska, Inc., Anchorage, Alaska IV CONTENTS m Preface Introduction 1 Acknowledgments 1 Classification of mineral deposits 2 Lode deposit types 2 Placer deposits 6 Explanation of tabular headings 7 Lode deposits 7 Placer districts 8 Abbreviations 8 Conversion factors 8 Significant metalliferous lode deposits, Brooks Range 9 Significant metalliferous lode deposits, Seward Peninsula 18 Significant metalliferous lode deposits, west-central Alaska 23 Significant metalliferous lode deposits, east-central Alaska 32 Significant metalliferous lode deposits, Aleutian Islands and Alaska Peninsula 41 Significant metalliferous lode deposits, southern Alaska 47 Significant metalliferous lode deposits, southeastern Alaska 59 Significant placer districts of Alaska 73 References 83 Indexes to metalliferous lode deposits and placer districts 97 PLATES [In pocket] 1. Map showing locations of significant metalliferous lode deposits of Alaska. 2. Map showing locations of significant metalliferous placer districts of Alaska. Contents v Significant Metalliferous Lode Deposits and Placer Districts of Alaska 1 2 By Warren j. Nokleberg, Thomas K. Bundtzen, Henry C. Berg, David A. Brew, Donald Grybeck, MarkS. Robinson, 1 Thomas E. Smith, and Warren Yeend INTRODUCTION as all metalliferous mines, prospects, deposits, or occurrences that the authors and contributors Alaska is commonly regarded as one of the judged to be important, on the basis of size, new frontiers in North America for discovering geological importance, or interest, for an in metalliferous mineral deposits. A major theme in depth survey. For each deposit, the report also the history of the State has been repeated states for each deposit a precise location, "rushes" or 11stampedes11 to sites of newly dis common names, major metals or commodities, a covered metalliferous lode or placer deposits. mineral deposit type, the host-rock geology, During the last two decades, there has been data on tonnage, grade, and production, if extensive exploration for lode and placer known, and sources of information. The location mineral deposits by private mining exploration of metalliferous lode deposits is shown on plate companies. During the same period, because of 1; the location of placer districts is shown on the considerable interest in Federal lands in plate 2. Alaska, and the establishment of new national parks, wildlife refuges, and Native ACKNOWLEDGM£'NTS corporations, substantial studies of mineral deposits and of the mineral resource potential This report is the result of efforts of the of Alaska have been conducted by the U.S. Geological Society of America to publish a Geological Survey, the U.S. Bureau of Mines, and series of volumes for the Decade of North Ameri the Alaska Division of Geological and can Geology (DNAG) on the geology of North Amer Geophysical Surveys. These studies have resulted ica. We thank George Plafker and David L. Jones, in abundant new information on Alaskan mineral the editors of the volume on Alaskan Geology, deposits. In the same period, substantial for their encouragement. We thank Donald A. geologic mapping has been completed with the Singer and Frederic H. Wilson for their reviews. advent of modern logistical and technical tools. Dennis P. Cox greatly assisted in classification One result of the bedrock studies has been the of mineral deposits. recognition of numerous fault-bounded packages designated as tectonostratigraphic terranes, PREVIOUS STUDIES each with a distinctive stratigraphy, structure, metamorphism, and suite(s) of mineral deposits. Within the last 23 years, a few statewide Proponents of this concept suggest that most of s um m a r i e s an d s e v e r a 1 reg i o n a 1 s u mm a r i e s of Alaska consists of a collage of tectono Alaskan metalliferous lode and placer deposits stratigraphic terranes (Jones and others, 1984b; have been published by the U.S. Geological Sur Monger and Berg, 1984). vey (USGS), and the Alaska Division of Geologi This report provides new and timely, de cal and Geophysical Surveys (ADGGS). In 1964, tailed tabular summaries of the 262 significant the USGS published a map of placer gold occur metalliferous lode deposits and districts, and rences (Cobb, 1964). In 1967, the USGS published the 43 placer districts of Alaska as of early a statewide summary of metalliferous lode depos 1986. The term "significant deposits" is defined its (Berg and Cobb, 1967). In 1973, the USGS published a summary of Alaskan placer deposits (Cobb, 1973). In 1976 and 1977, the USGS pub 1 Alaska Division of Geological and Geophysical lished a series of regional tables, maps, and Surveys. references for metalliferous deposits as part of 2 115 Malverne Avenue, Fullerton, California. the Regional Mineral Resource Assessment Program Previous Studies 1 (RAMRAP). These RAMRAP reports cover the Brooks deposits. Some models are descriptive (empiri Range (Grybeck, 1977), the Seward Peninsula cal), in which instance the various attributes (Hudson and others, 1977), central Alaska (Eber are recognized as essential, even though their lein and others, 1977), the eastern part of relationships are unknown. An example of a des southern Alaska (MacKevett and Holloway, 1977a), criptive mineral deposit model is the basaltic and the western part of southern Alaska (MacKe Cu mode 1, as adapted for this study, in which vett and Ho 11 oway, 1977b ). In 1981, the USGS the empirical datum of a geologic association of published a report on all known mines, pros Cu sulfides with relatively Cu-rich metabasalt pects, deposits, and occurrences for south or greenstone is the essential attribute. Other eastern Alaska (Berg and others, 1981). In 1982, models are genetic (theoretical), in which case the Arctic Environmental Information and Data the attributes are related through some funda Center (AEIDC) published a series of regional mental concept. An example is the W or Fe skarn mineral terrane maps of Alaska, prepared by C. (contact metasomatic) deposit model in which C. Hawley and Associates, showing the location, case the genetic process of contact metasomatism size, and type of major metalliferous mineral is the essential attribute. For additional in deposits (AEIDC, 1982). In 1984, the USGS pub formation on the methodology of mineral deposit lished a report summarizing the regional models, the reader is referred to the discussion geology, metallogeny, and mineral resources of by Cox and Singer (1986). southeastern Alaska (Berg, 1984 ). In recent years, a yearly listing of Alaskan lode and Lode Deposit Types placer deposits has been published by the ADGGS; the most recent publication is by Eakins and Kuroko massive sulfide deposit (Donald A. others (1985). Also during the last two de Singer in Cox and Singer, 1986). This deposit cades, many commodity studies have been pub- type consists of volcanogenic, massive to dis 1 i shed by the USGS, the U.S. Bureau of Mines, seminated sulfides that occur in felsic to in and the ADGGS; these commodity studies are cited termediate marine volcanic, pyroclastic, and below in the descriptions of specific deposits. bedded sedimentary rocks. The volcanic rocks are One important recent commodity study was pub mainly rhyolite and dacite with subordinate lished by Orris and Bliss (1985) on placer de basalt and andesite. The deposit iona 1 environ posits of the United States. ment is mainly hot springs related to marine volcanism in island arcs or in extensional re gimes. The d ep os it mineral s inc l ud e py ri te, CLASSIFICATION OF MINERAL DEPOSITS chalcopyrite, sphalerite, and lesser galena, tetrahed rite, tennant i te, and magnetite. Local Metalliferous lode deposits in this report alteration to zeolites, montmorillonite, silica, are classified into 29 types, and placer de chlorite, and sericite may occur. Notable exam posits are classified into 4 types, described ples are the Arctic, Smucker, and Sun deposits below. This classification of mineral deposits in the Brooks Range, the WTF, Red Mountain de was mainly derived from the mineral deposit posits, and Delta district deposits in east models of specialists as compiled in Cox and central Alaska, and the Greens Creek, Glacier Singer (1986), and to a lesser degree from ear Creek, Khayyam, and Orange Point deposits in lier studies of Erickson (1982) and Cox (1983a, southeastern Alaska. b). Four mineral deposit models for metallifer Besshi massive sulfide deposit (Dennis P. ous deposits common in Alaska were formulated Cox in Cox and Singer, 1986). This deposit type for this study. These additional models are for consists of thin, sheetlike bodies of massive to metamorphosed sulfide, Cu-Ag quartz vein, fel well-laminated pyrite, pyrrhotite, and chalcopy sic-plutonic U lode, and placer Sn deposits. The rite, and lesser sulfide minerals, within thinly lode deposit types are lis ted in order from laminated clastic sedimentary rocks and mafic those formed at or near the surface, such as tuffs. The rock types are mainly marine clastic various stratiform deposits, to those formed at sedimentary rocks, basaltic and less commonly deeper levels, such as zoned mafic-ultramafic andesitic tuff and breccia, and local black and podiform chromite deposits. Placer deposit shale and red chert. The depositional environ types are listed last. Some lode deposit types ment is uncertain, but may possibly be submarine that share a common origin, such as contact hot springs related to submarine basaltic vol metasomatic or porphyry deposits, are grouped canism. Associated minerals include sphalerite, together under a single heading. For a few lode and lesser magnetite, galena, bornite, and deposits, 1a ck of data precludes class i fi cation tetrahedrite, with gangue quartz, carbonates, into a specific mineral deposit type. For these albite, white mica, and chlorite. Alteration is deposits, a brief description of the deposit is sometimes difficult to recognize because of enclosed in parentheses under the "Type" heading metamorphism. Notable examples are the Midas, in table 1. Latouche, Beatson, Ellamar, and Fidalgo-Alaska The mineral deposit models used in this mines in the Prince William Sound region of report and as described· in Cox and Singer (1986) southern Alaska. consist of both descriptive and genetic informa ~ massive sulfide deposit (Donald A. tion that is systematically arranged to describe Singer in Cox and Singer, 1986). This deposit the essential properties of a class of mineral type consists of massive sulfides in pillow 2 Significant Metalliferous Lode Deposits and Placer Districts of Alaska