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Geology of the Sumdum Copper-Zinc Prospect, Southeastern Alaska
From abstract: The Sumdum copper-zinc prospect is in an alpine region on the mainland of southeastern Alaska, about 50 miles southeast of Juneau and about 25 miles west of the Canadian boundary. The ore-bearing outcrops at the prospect were discovered by the Alaska Helicopter Syndicate during the summer of 1958. The prospect is within a few thousand feet of the western margin of the . Coast Range batholith in regionally metamorphosed rocks that locally -have -been contact: metamorphosed. Most of the known ore deposits are -in the intermediate unit of three metamorphic-rock units that were mapped.
Geology of the North Bradfield River Iron Prospect, Southeastern Alaska
From abstract: The North Bradfield River iron prospect is in southeastern Alaska in rugged terrain about 8 miles southwest of the Canadian boundary and about 15 miles northeast of the head of Bradfield Canal. The prospect includes several magnetite-rich ore bodies of pyrometasomatic origin that are localized in skarn. The skarn forms a small part of a northwestward-trending roof pendant that is enclosed in the composite Coast Range batholith. The dominant rocks of the roof pendant are gneiss, granulite, schist, and marble. The ore, which consists almost entirely of magnetite, contains subordinate amounts of hematite, hydrous iron sesquioxides, pyrrhotite, chalcopyrite, and malachite. The ore bodies are crudely stratiform and apparently discontinuous. The largest ore body exposed is traceable for about 350 feet along its strike and averages about 25 feet in thickness. An accurate appraisal of the economic potential of the prospect was precluded by poor outcrops, local snow cover, and inadequate subsurface data.
Geology of Part of the Craig C-2 Quadrangle and Adjoining Areas, Prince of Wales Island, Southeastern Alaska
From abstract: The area mapped is on the east coast of Prince of Wales Island, southeastern Alaska, about 35 miles northwest of the town of Ketchikan. Deposits of magnetite and copper in the mapped area and on Kasaan Peninsula, which adjoins it on the southeast, have been mined for copper and have produced more than 600,000 tons of ore valued at more than $6 million.
Geology of the Craig Quadrangle, Alaska
From abstract: The Craig quadrangle, in southeastern Alaska, lies entirely within the Tongass National Forest and includes a large part of Prince of Wales Island, the largest island of the Alexander Archipelago. Sedimentary, volcanic, and metamorphic rocks of Paleozoic and Mesozoic age are exposed as complexly folded and faulted sequences. Paleozoic rocks occupy a broad geanticlinal area comprising Prince of Wales Island and the islands to the west. Metamorphosed Mesozoic rocks form a geosynclinal area along and east of Clarence Strait. Granitic and dioritic stocks and masses, mainly of Mesozoic age, intrude the Paleozoic and Mesozoic rocks. Remnants of volcanic rocks of Tertiary age exist on Suemez Island, and scattered areas of Tertiary clastic rocks and volcanic rocks are exposed near Clarence Strait. Deposits of Quaternary age are mainly thin glacial deposits and narrow bands of stream alluvium.
Geology of the Mount McKinley Quadrangle, Alaska
From abstract: The Mount McKinley quadrangle, in south-central Alaska, includes parts of the Alaska Range, the Tanana and Kuskokwim lowlands, and the Kuskokwim Mountains. Schists of Precambrian age crop out in the northern foothills of the Alaska Range. Sedimentary and volcanic rocks of Paleozoic and Mesozoic age are exposed in the Kuskokwim Mountains, where little is known of their distribution and character, and in the Alaska Range, where they occupy the axial part and northern limb of a great synclinorium. Granitic batholiths, largely of Mesozoic age, intrude the Paleozoic and Mesozoic rocks in the Alaska Range.
Tofty Tin belt, Manley Hot Springs District, Alaska
From abstract: Buried placer deposits in a belt about 8 miles long by 1 mile wide at Tofty, near Manley Hot Springs, Alaska, have yielded a few hundred tons of cassiterite as a byproduct to the recovery of several million dollars in placer gold.
Geology and Coal Resources of the Homer District, Kenai Coal Field, Alaska
From abstract: The Homer district of the Kenai coal field is about 100 miles southwest of Anchorage, in south-central Alaska. It covers an area of about 1,100 square miles on the west side of the Kenai Peninsula, between Tustumena Lake and Kachemak Bay. The principal settlement is Homer, at the southern end of the district, which is connected by the gravel-surfaced Sterling Highway with the Alaska highway system and The Alaska Railroad, and is also served by ocean transportation and one airline.
Geology and Coal Resources of the Little Susitna District, Matanuska Coal Field, Alaska
From introduction: This report is based on preliminary surface mapping in the summer of 1952 and on subsurface exploration with a bulldozer powerauger unit in the summers of 1953 and 1954. In 1952 F. F. Barnes was assisted by Alfred Oestreich, geologist, and Lewis Ladwig and Richard Pack, field assistants. From July 2 to August 31, 1953, F. F. Barnes and Daniel Sokol were assisted by W.T. Ashlock and R. E. Rowland, field assistants, and by a bulldozer operator-mechanic. From June 23 to July 27, 1954, Barnes and Sokol were assisted by A. E. Burford and W. S. Hopkins, geologists, and an operator-mechanic.
Geology and Ore Deposits in the Reid Inlet Area Glacier Bay, Alaska
From abstract: A gold-bearing area of about 7% square miles near the head of Glacier Bay between Reid and Lamplugh Glaciers was first discovered by Mr. Joseph Ibach in 1924. The dominant rock type in the area is granodiorite, which is intruded into bedded rocks that may be of Paleozoic age. The bedded rocks consist of conglomerate, limestone, and black graphitic schist. A light-colored quartz diorite younger than the granodiorite crops out south of the mapped area.
Geology and Ore Deposits of Northwestern Chichagof Island, Alaska
From introduction: The area of this report is in the northern part of southeastern Alaska (fig. 39). It includes about 400 square miles on northwestern Chichagof Island, latitude 5747' to 58*15' N. and longitude 135 57' to 136 35' W. It is covered by U. S. Geological Survey Mount Fairweather A-1, A-2, and Sitka D--7 and D-8 topographic quadrangle maps. The writer's geologic investigation was started in 1946 as a continuation of earlier work on the west coast of Chichagof Island by J. C. Reed and R. R. Coats (1941) of the U. S. Geological Survey.
Geology of Geikie Inlet Area, Glacier Bay, Alaska
From abstract: The Geikie Inlet area is in the Glacier Bay region of southeastern Alaska, about 100 miles northwest of the city of Juneau. The area is mountainous with relief of slightly more than 5,000 feet, and the coastline is deeply indented by fiords and inlets. Most of the western half of the area is covered by glaciers.
Geology of the Mount Katmai Area, Alaska
From abstract: The Mount Katmai area is on the Alaska Peninsula and comprises the Mount Katmai quadrangle, the Cape Douglas area of the adjoining Afognak quadrangle, and parts of the Karluk and Naknek quadrangles. The area, which includes nearly all the Katmai National Monument, is one of high relief and is drained by streams of preglacial origin. At least two ice advances are indicated by the moraine configuration. Present-day glaciation is restricted to numerous alpine glaciers in the mountain areas. Fifteen recently active volcanoes roughly form a line from Mount Douglas to Martin Mountain.
Reconnaissance for Radioactive Deposits in Southeastern Alaska, 1952
From abstract: Reconnaissance for radioactive deposits in southeastern Alaska in 1952 was centered in three localities: the northern part of Prince of Wales Island and parts of adjacent islands, the Taku Harbor-Point Astley district, and the Hyder area. Significant concentrations of radioactive minerals were found only in the vicinity of Salmon Bay on the northeastern shore of Prince of Wales Island. In this area radioactive carbonate-hematite veins occur along the coast for about 8 miles. The veins are generally short, irregular, and lenticular, but a few can be traced for more than 300 feet between the low-tide line and the forest cover. The width of the veins normally ranges from less than 1 inch to 2.5 feet; several, however, are 5 to 10 feet wide.
Geology and Coal Deposits, Jarvis Creek Coal Field, Alaska
From abstract: The Jarvis Creek coal field lies on the north side of the Alaska Range, between latitudes 63 35' and 63*45' N., and longitudes 145*40' and 145*50' W. It is 3 to 6 miles east of the Richardson Highway. The coal field is about 16 square miles in area, the major part of which is a rolling plateau that slopes gently northward and is bounded on the east, south. and west by bluffs facing Jarvis Creek, Ruby Creek, and the Delta River.
Radioactivity Investigations at Ear Mountain, Seward Peninsula, Alaska, 1945
From abstract: Radioactive material in apparently significant amounts was recognized in heavy-mineral concentrates from the gravels of four streams that head in Ear Mountain, Alaska, when collections of the United States Geological Survey were examined for radioactivity in the winter of 1944-45. This area, on the north side of the Seward Peninsula, attracted attention in 1901-02 when cassiterite was discovered in the streams. Subsequent attempts were made to develop copper- and tin-bearing lode deposits.
Geology of the Prince William Sound Region, Alaska
From introduction: This paper describes the geology of the Prince William Sound region, a part of south-central Alaska. It deals with the rocks of a section of the Coast Ranges that has been studied by various geologists over a period of many years and still offers basic problems that are unsolved. Prince William Sound is well known for its mining activities, but the intention here is to describe the areal and stratigraphic geology of the district rather than its mineral resources and to present a statement that will serve as a report of progress and a basis for more detailed field work.
Gypsum Deposits near Iyoukeen Cove, Chicagof Island, Southeastern Alaska
From abstract: Two deposits of high-grade gypsum are located near tidewater at Iyoukeen Cove, on the northeastern part of Chichagof Island, southeastern Alaska. A group of claims, formerly operated by the Pacific Coast Gypsum Co., was acquired by the Kaiser Gypsum Division of Kaiser Industries, Inc., during World War II. Claims at the other deposit are held by Dave Housel of Juneau and Seattle, Washington, in the name of the Gypsum-Camel group.
Gypsiferous Deposits on Sheep Mountain, Alaska
From abstract: Gypsum-bearing rocks crop out in Gypsum and Yellow Jacket Gulches, on Sheep Mountain, which is about 90 miles northeast of Anchorage, Alaska. The gypsiferous rock occurs in deposits of irregular shape in the greenstone. Both the gypsiferous rock and the greenstone are hydrothermal alteration products of the volcanic rocks of Jurassic age which comprise the bulk of the mountain. Near-surface samples of the gypsiferous rock contained an average of 25 to 30 percent gypsum ; some contained as much as 50 percent. Quartz, alunite, clay, sericite, and pyrite are contaminating constituents of the ore. Six of the largest and most accessible of the gypsum deposits were mapped and calculations show that three of the deposits contain an aggregate of approximately 311,000 short tons of indicated gypsiferous rock and four of the deposits contain 348,000 short tons of inferred gypsiferous rock.
Geology of the Portage Pass Area, Alaska
Abstract: The Portage Pass area is in south-central Alaska, and includes part of the narrow neck of land that joins the Kenai Peninsula with the mainland to the north. This region is in general mountainous, elevations ranging from sea level to more than 4,000 feet on the peaks bordering the area. Several glaciers, all of which are apparently receding, extend into the area. Vegetation, chiefly alder and cottonwood on the valley lowlands and some spruce and hemlock on the lower slopes, extends to an elevation of about 1,000 feet, above which the slopes are bare except for occasional clumps of brush. The bedrock of the entire area is slate, argillite, and graywacke, apparently part of the same great series that extends from the Kenai Peninsula into the Prince William Sound region and is at least in part of Cretaceous age. The only igneous rocks recognized in the area are a few acidic dikes and a small diabase dike. Small, irregular quartz veinlets are widespread. The structure is not only complex but, owing to extensive metamorphism, is in many places obscure. A general northeast strike and steep to vertical dips of both bedding and cleavage planes are the rule, but there appears to be some broad folding along steeply northeast-pitching axes. Although no large faults have been recognized, much movement has occurred along many small faults, shear zones, and bedding planes. All observed faults and shear zones trend northeastward. There are no mines in this area. Some mineralization of quartz veins was noted at a few places, and some prospecting has been done, but no workable deposits are known.
Geology of the Gerstle River District, Alaska, with a Report on the Black Rapids Glacier
From abstract: The area here described includes most of the north side of the Alaska Range between the Delta and Johnson Rivers, in one direction, and the axis of the Alaska Range and the Tanana River in the other. Besides the Delta River, its principal streams are Jarvis Creek, the Gerstle and Little Gerstle Rivers, and, at the extreme east, the Johnson River, all of which have glacial sources.
Occurrences of Molybdenum Minerals in Alaska
Abstract: In the accompanying report reference is made to all of the deposits in Alaska in which molybdenum minerals have been definitely recognized and reported. None of the deposits have been mined commercially, and none of them have been prospected thoroughly enough to afford quantitative estimates as to their tenor and potential reserves ; in fact, at only a few of the localities has there been more than surficial testing. Forty-one separate and distinct localities where molybdenum minerals occur are listed, and the available information on factors of geologic significance regarding each occurrence is given. A small-scale map of Alaska on which the various localities are indicated forms part of the bulletin, and in the text are extensive references to the various published reports and records of the Survey upon which the statements are based. In spite of the widespread distribution of molybdenum mineralization in Alaska, the remoteness of many of the localities, their handicap through dearth of transportation facilities and labor supplies, and the already wellsupplied condition of the American market for molybdenum ores discourage the early development of any of the known deposits or search for them in unsurveyed areas. These draw-backs will doubtless become -less important factors as the settlement and development of Alaska as a whole takes place. It is, therefore, with a view to the future that one must consider these deposits, and from that standpoint it becomes evident that some of them merit watchful consideration.
Tertiary Deposits of the Eagle-Circle District, Alaska
From introduction: The present report aims to supply additional information regarding the Tertiary deposits, which are the source of most of the gold placers now being worked in that part of the Eagle-Circle district lying south of the Yukon River. The work was conducted from base camps along the river, but the belt of Tertiary rocks is at places as much as 20 miles from the Yukon, so that it is not easily accessible from the river except in the vicinity of mining camps, where roads or trails have been constructed southward.
Geology of the Upper Tetling River District Alaska
From introduction: This paper describes the geology of a part of the Alaskan Range that lies in the headwater region of the Copper and Tanana Rivers.
Mineral Industry of Alaska in 1939
From Introduction: "The presentation of a yearly record of the Alaska mineral industry is a continuing service that has been rendered by the Geological Survey from almost the earliest years of extensive mining in Alaska, and the present report for 1939, is the thirty-sixth of this series.These reports therefore serve miners, prospectors, and businessmen concerned with Alaska affairs as useful historical records, statements of contemporary conditions, and starting points on which some conjectures concerning future operations may be predicated."
Past Lode-Gold Production from Alaska
From abstract: This report presents an analysis of the statistical records of the Geological Survey regarding the production of lode gold from the Territory of Alaska for the period 1882 to 1937, inclusive. During that time lode gold to the value of $172,368,000 had been mined. The history of the discovery of lode gold and the early developments in lode-gold mining in each of the various districts is outlined briefly, and the production of lode gold in each of the geographic subdivisions is tabulated fully for each year, as far as the records and the practices of the Geological Survey permit.
Mineral Industry of Alaska in 1938
From introduction: The presentation of a yearly record of the Alaska mineral industry is a continuing service that has been rendered by the Geological Survey from almost the earliest years of extensive mining in Alaska, and the present report, for 1938, is the thirty-fifth of this series. 2 Such a record, especially when supplemented by the statistics for the preceding years, not only affords an authoritative summary of current 'and past conditions but also indicates trends that are of significance in suggesting the lines along which future developments of the industry are likely to proceed. These reports therefore serve miners, prospectors, and businessmen concerned with Alaska affairs as useful historical records, statements of contemporary conditions, and starting points on which some conjectures concerning future operations may be predicated.
The Eska Creek Coal Deposits Matanuska Valley, Alaska
The coal deposits in the vicinity of Eska Creek, a small tributary from the north to the Matanuska River, are a part of the Matanuska coal field. One of the two commercial coal-producing districts in Alaska, this field is in the southcentral part of the Territory, at the head of Cook Inlet. It is 170 miles from Seward, the ocean terminus of the Government-owned and -operated Alaska Railroad, and is served by a branch line of that railroad.
The Kaiyuh Hills, Alaska
From introduction: The present report states the results of an exploratory survey of the Kaiyuh Hills during the summer of 1934.
Kodiak and Adjacent Islands, Alaska
From abstract: The Kodiak group of islands, having an area of 4,900 square miles, lie on the Pacific Ocean side of the base of the Alaska Peninsula. Although the town of Kodiak is the oldest continuously occupied white settlement in Alaska, the interior of many of the islands is still little explored and unmapped, for the heavy growth of vegetation makes inland travel difficult, and few trails penetrate far from the coast.
Kodiak and Vicinity Alaska
From abstract: Kodiak Island, although the site of the earliest white settlement in Alaska and the center of a vigorous fishing industry, is still largely unexplored, except for a strip immediately adjacent to the shores. The heavy growth of vegetation makes access to the interior of the island difficult, and few trails penetrate far from the coast. Mining activity in the past has been confined to somewhat desultory exploitation of beach sands, which in places carry gold, though some gold-bearing lodes have been staked, and a few unsuccessful attempts at lode mining have been made.
Mineral Industry of Alaska in 1935
From introduction: The record of the Alaska mineral industry for 1935, here presented, is supplemented by records for earlier years, because in that way certain trends may be recognized which are not only of historical significance but are also useful in suggesting the course that the industry is likely to take in the future. This is a continuing service that has been rendered by the Geological Survey from almost the earliest years of active mining in Alaska, and the present report is the thirty-second of the series.
Mineral industry of Alaska in 1934
From Introduction: "The value of its mineral resources has long been recognized as a matter of concern in the welfare of every nation, and all wise governments almost from time immemorial have taken steps to find out about, utilize, and safeguard such of these natural resources as lie within their own boundaries or to acquire rights in those they need that lie outside those boundaries. Obviously one of these lines concerns itself with the record of present performance-how much of the different mineral commodities is the country at present producing, where does this production come from and what are the facts as to the current developments in the industry? To answer some of these questions authoritatively is part of the work of the Alaskan branch of the Geological Survey, and answers to those questions for the year 1934 are given in the accompanying report."
The Willow Creek-Kashwitna District, Alaska
From introduction: The district described in this report is a triangular area covering about 300 square miles in the southwestern part of the Talkeetna Mountains. The Kashwitna River forms the northern boundary, the Susitna Valley flats the western, and the Willow Creek gold district, which is in the extreme southwestern part of the Talkeetna Mountains, the southern. As the area examined is not a distinct geographic unit, its boundaries being arbitrarily chosen and set only by the limitation of time spent in the field, a description of its geography applies to practically the entire western and southern portions of the Talkeetna Mountains, of which it is a part.
Core Drilling for Coal in the Moose Creek Area, Alaska
From abstract: The Moose Creek area is in the western part of the Matanuska Valley, in south-central Alaska, about 165 miles by railroad north of the coast at Seward. Coal deposits in the valley have been known since the early 1890's, and there have been producing mines since 1916, but the annual production is only about 40,000 tons, or less than one-third of the total amount consumed in the Territory. Early in 1931 Congress authorized the investigation of mineral resources in areas tributary to the Alaska Railroad, which is Government owned and operated, for the purpose of stimulating development and hence increasing the traffic and revenue of the railroad. The technical work of carrying on these studies was entrusted by Col. O. F. Ohlson, general manager of the railroad, to the United States Geological Survey. One of the investigations undertaken was that of the Moose Creek area, where small coal mines are in operation. Difficulties have been encountered in these mines, owing to the faulted character of the formation, which causes unproductive work in mining and also produces a large percentage of fine coal, which is unsuitable for sale in distant markets. Field examination indicated that more favorable mining conditions might be found somewhat farther west. Core drilling was therefore done in 1932, in order to learn if workable beds of coal were present that might he mined at less cost and produce a better product than the present mines for competitive sale in markets of the Pacific coast.
The Curry District, Alaska
From abstract: The Curry district lies on the south flank of the Alaska Range, on the southeast side of Mount McKinley. Most of it is west of the Alaska Railroad. The eastern portion can be easily reached from several points along the railroad route, but the western portion is much more difficult of access, owing to the numerous glacial streams and the rugged topography. The relief of the area is great, the elevation ranging from 500 feet along the Chulitna River to 20,300 feet at Mount McKinley. The Chulitna River, a tributary of the Susitna River, drains the larger part of the area described. It flows in a broad valley in the eastern part of the district, and here the maximum relief is about 3,000 feet. The western part of the district is very rugged, with numerous peaks over 6,000 feet in elevation which have sheer slopes and almost unscalable pinnacles. Winding down through this maze of rugged mountains are four major valley glaciers-Eldridge, Buckskin, Ruth, and Tokichitna-and many tributary and smaller glaciers. Practically the entire district, with the exception of the higher peaks and ridges, has been glaciated. Timber grows along the main streams and extends to an elevation of 2,000 feet, but a large portion of the district lies above that elevation.
Notes on the Geology of the Alaska Peninsula and the Aleutian Islands
Abstract: During the spring of 1932 an opportunity was offered by the United States Navy for a geologist to accompany an expedition organized to make a reconnaissance of the western part of Alaska Peninsula and the Aleutian Islands. This expedition visited several localities the geology of which was little known. It was found, as had already been expected, that the islands west of Unimak Pass are composed mainly of basic volcanic lavas and fragmental materials, into which have later been injected dikes, sills, and considerable masses of intrusive rocks, some of which are of acidic types and of granitic texture. These westward islands are bordered both to the north and south by depressions 2,000 fathoms or more in depth, and the islands have apparently been built up from that depth by the ejection and extrusion of volcanic materials since early Tertiary time. No rocks of proved pre-Tertiary age were seen, and the only sedimentary materials present may well have been derived from the erosion of the volcanic islands after they were built up above sea level. On the Alaska Peninsula pre-Tertiary sediments through which the volcanic materials broke to the surface are abundantly present. There is evidence that all the larger islands and the higher portions of the peninsula were severely glaciated during Pleistocene time. Each of the larger islands was the center of ice accumulation and dispersal, and the present topography, except upon recently active volcanic cones, shows strongly the effects of glacial sculpture.
Upper Copper and Tanana Rivers, Alaska
From introduction: Two field parties, one topographic, the other geologic, were engaged in making surveys in the section of the Alaska Range between the Nabesna and Big Tok Rivers in 1934. Most of the area surveyed was on the northeast side of the range, within a drainage area that is tributary to the Nabesna and Tanana Rivers, but it also included a small part of the Copper River Basin.
Past Placer-Gold Production from Alaska
"To the end of 1930 Alaska, according to the records of the Geological Survey, had produced placer gold to the value of $258,962,000 from mines widely scattered throughout its length and breadth. The distribution of the placers from which the gold was recovered has been stated in more or less detail in the annual summaries published by the Geological Survey on the mineral industry of Alaska and also in its more complete reports on many of the individual mining districts. Although these summaries and reports have furnished information regarding the larger regions, they have not always given specific details regarding the smaller districts. Furthermore, there has been no recent attempt to assemble and publish in one place the scattered statistics regarding the placer-gold production by years and by regions and districts. The purpose of the present report is to set forth in condensed but comprehensive form a summary of the placer-gold production of Alaska so far as it can be determined from the available official records."
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