The following is excerpted from the USGS
publication PRINCIPAL GOLD-PRODUCING DISTRICTS OF THE UNITED STATES
By A. H. Koschmann and M. H. Bergendahl. This publication is invaluable
for those wishing an overview of gold production in the United sates,
and in particular it is useful in determining areas that may be worth
prospecting in the future. The Alaska portion of the publication is
being reproduced here as time allows.
DISTRICTS OF THE UNITED STATES
By A. H. Koschmann and
M. H. Bergendahl
United States Geological Survey Professional Paper 610 : 1968
Gold, the lure that drew settlers across the wide
prairies and into the most remote mountain gullies in our Western States,
proved also to be the dominant factor in the settlement of Alaska. This
most important mineral commodity of the State was known in Alaska as
early as 1848, long before the territory was acquired from Russia by
the United States in 1867. P. P. Doroshin, a Russian mining engineer,
made the discovery in the gravels of the Kenai River on the Kenai Peninsula,
but there was no great excitement and apparently no gold was mined (Martin
and others, 1915, p. 181-182). A second discovery of placer gold in
1865-66 on the Seward Peninsula by a party exploring for a telegraph
route similarly failed to arouse much interest (Collier and others,
1908, p. 13-14).
Alaskan gold mining began in southeast Alaska. In
1869 miners who had been disappointed in the Cassiar gold district in
British Columbia discovered gold placers at Windham Bay and Sumdum Bay
southeast of Juneau. In 1870-71 the first gold produced in Alaska, reported
to be worth $40,000, was extracted from these placers (Wright, 1906,
p. 2). At about this time the first attempts to mine lode gold were
made near Sitka (Knopf, 1912, p. 8). In the early 1870’s extensive copper
deposits were found on Prince of Wales Island, but because of the remoteness
of the area from transportation facilities, these were not developed
for many years. The major lode gold deposits of Alaska were found in
1880 at Juneau, and by 1883 Juneau was the mining center of the territory
(Wright, 1906, p. 3). Encouraged by the successes at Juneau, the prospectors
spread through southern Alaska and made important gold discoveries at
Berners Bay and Eagle River on the mainland near Juneau, at Klag Bay
on Chichagof Island, at Willow Creek near Anchorage, and even on far-off
Unga Island, 1,000 miles to the west.
Numerous gold districts, the most important of which
are Nome, Council, and Fairhaven, are on the Seward Peninsula. This
region was prospected first by gold seekers drawn north by the great
Klondike (Yukon Territory, Canada) rush of 1897-98. By 1898 the discovery
of the rich Nome placers triggered a stampede to the new area and led
to the rapid development of the entire peninsula. Nome, the second largest
gold-producing district in Alaska, was active until 1962.
The vast Yukon drainage basin has produced more gold
than any other region in Alaska, even though it was the most recent
of the gold-producing regions to be exploited. With transportation virtually
limited to river travel, the great distances from gold deposits to supply
and population centers inhibited any large-scale mining in the early
days. The first gold discoveries were made in 1878 (Mertie, 1937, p.
4); however, tales of gold had been circulated years earlier by traders
and trappers who set up posts at various points along the Yukon River.
Smith (1933, table facing p. 96) listed the earliest production for
this region in 1883 from the Fortymile district. The important placers
at Fairbanks were discovered in 1902, and by 1910 lode mines were active
in this district. The Fairbanks placers proved amenable to large-scale
dredging operations, which soon made this district the largest gold
producer in Alaska.
As transportation facilities improved after 1900,
new gold discoveries were made in the more remote areas, and previously
known deposits were developed and mined. This activity extended into
the 1930’s, and several lode and placer districts in the Yukon basin
were activated in this interval.
Gold mining in Alaska was seriously affected in 1943
by the imposition of War Production Board Order L-208 which closed nearly
all of the gold mines during World War 1I (fig. 4). After the war the
placer mines of the Fairbanks district resumed large-scale operations,
and this single district accounted for more than half the total annual
gold production for Alaska during 1950-65. The lode mines in Alaska
were virtually inactive during 1942-65.
Of the total value of $722,122,186 of gold (28,859,718
ounces) produced in Alaska from 1880 to 1957, $504,076,577 came from
placer mines (U.S. Bureau of Mines, 1957, p. 83, 85). During 1958-59
the gold production amounted to 365,353 ounces, most of which came from
placers (U.S. Bureau of Mines, 1959, p. 84). Most of the lode gold has
come from the Juneau district in southeast Alaska, and an unknown but
probably small amount has been produced as a byproduct of copper ores
in the Prince William Sound region. The gold production of Alaska before
1880 is unknown, but probably was not great.
Emmons (1937, p. 203) discussed the general relationships
of gold deposits to geology. He pointed out that the chief lode deposits
are associated with Mesozoic granite that have intruded rocks of Precambrian,
Paleozoic, and Mesozoic ages. This belt of intrusives extends from the
Seward Peninsula to the Yukon Territory. The lode deposit on Unga Island
in the Aleutian Islands is in Tertiary andesite. The placer deposits
are widespread, occurring along nearly all the major rivers and their
tributaries, and even in beach sands in the Nome area, on Kodiak Island,
Yakataga, Lituya Bay, and Cook Inlet.
As in earlier reports of the Geological Survey (for
instance, Smith, 1939), the State is subdivided into nine geographical
regions: Cook Inlet-Susitna, Copper River, Kuskokwim, Northwestern,
Seward Peninsula, Southeastern, Southwestern, Yukon, and Prince William
Sound. The regions and the individual districts within the regions are
discussed in this report.
Fig. 4 Alaska Gold Production 1880-1965
COOK INLET-SUSITNA REGION
Bounded roughly by the Aleutian or Alaska Peninsula
on the southwest, the Alaska Range on the west and north, and by the
Talkeetna Mountains on the east, the Cook Inlet-Susitna region includes
the Kenai Peninsula, Valdez Creek, Willow Creek, and Yentna-Cache Creek
Gold was first discovered in Alaska in 1848 in the
gravels of the Kenai River. Apparently this gold was not present in
minable quantities, and it was not until the 1890's that minable placers
were found in the Turnagain Arm area (Martin and others, 1915, p. 181-183).
The first lode deposits in the Cook Inlet-Susitna region were found
in 1896 also in the Turnagain Arm area, more precisely, the Moose Pass-Hope
area; however, the deposits, although rich, were of small tonnage, and
there was very little lode production before 1911 (Martin and others,
1915, p. 129-131).
Placers in the Valdez Creek district, in the southern
foothills of the Alaska Range, were worked from 1904 to 1924 (Ross,
1933b, p. 427-428) and desultory operations were carried on as recently
as 1947 (E. H. Cobb, written communication, 1962).
In the western part of the Cook Inlet-Susitna region,
placers were discovered in the Yentna-Cache Creek district in 1905 (Capps,
1913, p. 10). These deposits were moderately productive through 1957.
The most productive district in the entire region is the Willow Creek
district, about 20 miles north of the towns of Palmer and Wasilla, where
placers were discovered in 1897. The first lode claims were located
in 1906 (Capps, 1913, p. 50) and were worked fairly steadily until the
From 1880 through 1959, a recorded total of 919,532
ounces of gold was produced from the Cook Inlet-Susitna region. Of this,
598,361 ounces was from lode mines, 324,370 ounces from placers, and
6,801 ounces from undifferentiated sources. After the end of World War
II production from both lode mines and placers declined markedly.
KENAI PENINSULA DISTRICT
The Kenai Peninsula is near the center of the southern
coastline of Alaska, immediately northeast of the Alaska Peninsula.
The districts of Moose Pass-Hope, Girdwood, and Turnagain
Arm - all in the central and northern part of the peninsula - have been
combined in this discussion because most of their production data have
been combined under "Kenai Peninsula."
Numerous small placers were discovered in the Turnagain
Arm area in the early 1890's, but no significant production occurred
until news of the auriferous gravels on Mills and Canyon Creeks brought
several thousand prospectors to the area in 1896 (Martin and others,
1915, p. 182-183). Two years later another influx occurred. In a short
time the small richer deposits were exhausted and the hand-operated
rockers and sluices were supplanted by hydraulic plants that successfully
mined the large reserves of low-grade gravels.
Lode mining, overshadowed by the placer operations,
has been conducted chiefly in the Moose Pass-Hope camp and to a lesser
degree in the Girdwood camp. The first indications of economic lode
deposits were noted in 1896, but interest was diverted for a number
of years to the more accessible placers. The lode deposit at the Hirshey
mine, discovered in 1911, became the most consistently productive in
the district (Tuck, 1933, p. 489-494). Lode mining continued sporadically
until the end of World War II, when it dwindled to almost nothing.
Total recorded gold production from the Kenai Peninsula
from 1895 through 1959 was 23,700 ounces from lodes, 96,500 ounces from
placers, and 175 ounces from undifferentiated sources. Data from 1931
through 1945 are incomplete, so that the figures given here are minima.
The geology of the Kenai Peninsula was described by
Martin and others (1915), Tuck (1933), and Park (1933). The oldest rocks
on the peninsula are schists and crystalline limestones of uncertain
age; however, the most widely distributed rocks are slates and graywackes
that range in age from Paleozoic or Early Triassic to possible Late
Cretaceous (Martin and others, 1915, p. 33-35). Granitic intrusive masses
are abundant in the slaty rocks along the southern and eastern coasts.
The Kenai Formation, of Eocene or younger Tertiary age, is exposed in
the low country in the southwest part of the peninsula, north of Kachemak
Bay, and consists of coal-bearing sand and clay. This formation is 15,000-20,000
feet thick and contains economically important oil and gas accumulations
(Lian and Simonson, 1962, p. 271). Quaternary gravels - mostly till,
outwash, and terrace sands and gravels - cover vast areas of lowlands
in the west and northwest parts of the peninsula. The pre-Tertiary rocks
that comprise most of the mountainous part of the peninsula are intricately
folded whereas the Tertiary rocks, which occupy the low areas of the
peninsula, are either horizontal or only gently warped into folds in
which dips are generally less than 10° (Barnes and Cobb, 1959, p. 227).
The lode deposits of the Moose Pass-Hope camp consist
of fissure veins. Mineralized acidic dikes are also in the district,
but the gold production has been from the fissure veins that cut across
the slaty cleavage of the slate and graywacke country rocks. The veins
strike in all directions and have an average dip of 45° north or west
(Tuck, 1933, p. 490). The ore minerals are arsenopyrite and small amounts
of galena, sphalerite, pyrite, and chalcopyrite in a gangue of quartz,
calcite, and ankerite (Tuck, 1933, p. 491). Free gold occurs in the
quartz, commonly near accumulations of galena and sphalerite.
The placer deposits of the Kenai Peninsula, described
by Martin, Johnson, and Grant (1915, p. 181-208), are most productive
in the northern part of the peninsula along the various streams - Crow,
Resurrection, Palmer, Bear, and Sixmile Creeks - that debouch into Turnagain
Arm. Farther south, the gravels of Canyon, Mills, Falls, and Cooper
Creeks, and of the Kenai River have yielded some placer gold. The deposits
were formed in Quaternary time by postglacial streams reworking and
resorting the debris that choked the valleys after the retreat of the
glaciers. Present streams that have incised their courses in the unconsolidated
material have left terraces and have further reworked the gravels. The
productive placers are along these streams and in channel deposits in
VALDEZ CREEK DISTRICT
The Valdez Creek district is on the southern flank
of the Alaska Range at approximately lat 63°12' N. and long 147°20'
W. The drainage area of Clearwater Creek in addition to that of Valdez
Creek is usually included in the district.
Gold was first discovered in this district in 1903,
in the gravels of Valdez Creek, but no production was recorded until
1908. The "Tammany Channel," a buried channel representing the course
of an ancestral Valdez Creek, yielded most of the placer gold from the
district. This channel, discovered in 1904, has been worked by hydraulic
and underground methods (Tuck, 1938, p. 113). The chief production has
been from placers. Several gold lodes were located, but none were productive
to 1936 (Tuck, 1938, p. 121), and no record of any later lode production
was found in 1959.
Total estimated gold production through 1936 was about
34,900 ounces, worth about $720,000 (Tuck, 1938, p. 113). The district
was virtually dormant during 1937-59.
The geology of the district was described in detail
by Ross (1933b, p. 428-444). Triassic(?) metasedimentary rocks - argillite,
slate, and sericite and chlorite schist with limestone lenses - were
intruded by a small batholith of quartz diorite in the northern part
of the district and by small stocks and plugs of diorite elsewhere in
the district. Structurally, the district is on the northwest flank of
a large northeast-trending anticlinal fold; large normal faults trending
N. 65° E. cut the metasedimentary rocks.
There are several types of veins in the district,
and those showing the most promise, according to Ross (1933b, p. 456),
are quartz veins associated with sheared and metamorphosed wallrocks.
In their unoxidized state these veins contain pyrite, arsenopyrite,
pyrrhotite, and a little chalcopyrite. Native gold occurs in the quartz.
Some quartz veins contain abundant calcite (Ross, 1933b, p. 457). Ross
(1933b, p. 458) believed the veins were related to hydrothermal activity
that followed the intrusion of the dioritic bodies.
The placers are buried channels in which gold was
concentrated next to the bedrock floor. The old gorges, eroded into
bedrock, are V-shaped and probably were cut into a mature erosion surface
(Ross, 1933b, p. 444-445).
WILLOW CREEK DISTRICT
The Willow Creek district, an area of about 50 square
miles, is 23 miles by road northeast of Wasilla and 21 miles northwest
Gold-bearing veins were discovered in this district
in 1906, but lack of transportation facilities hindered their development
and no production was recorded until 1909 (Ray, 1954, p. 35-36). After
1909 the district developed steadily and maintained substantial annual
production until 1951, after which there was only sporadic small-scale
activity. Total gold production through 1959 was 652,080 ounces; nearly
all production was from lode mines.
The geology and ore deposits of this district were
described by Ray (1954, p. 10-54). The oldest rock is muscovite-quartz-plagioclase
schist. Intruded into this is a mass of quartz diorite, the Talkeetna
batholith, which underlies the major part of the district. Dikes of
lamprophyre, diabase, aplite, and pegmatite cut the intrusive. The batholith
is believed to be of late Mesozoic age. Sedimentary rocks, including
conglomerate, arkose, shale, and sandstone of Tertiary(?) age, dip to
the south, away from the quartz diorite body. Numerous faults cut the
quartz diorite. Those with the larger displacements are postore in age,
trend northwest, and dip northeast.
Two types of veins are in the quartz diorite (1) an
older nonproductive group, containing assemblages of chalcopyrite-molybdenite,
pyrite-stibnite, or low-grade gold-quartz, and (2) minable gold-bearing
quartz bodies in shear zones that occur along the southern margin of
the quartz diorite. Vein minerals, in addition to quartz and gold, are
pyrite, arsenopyrite, sphalerite, chalcopyrite, tetrahedrite, nagyagite,
altaite, coloradoite(?), galena, stibnite(?), and sparse scheelite.
Gold commonly occurs as irregular grains in and around nagyagite and
as fracture fillings in pyrite, and locally occurs as blebs and stringers
YENTNA-CACHE CREEK DISTRICT
The Yentna-Cache Creek district includes about 2,000
square miles on the southeast slope of the Alaska Range and is located
roughly between lat 61°55' and 62°45' N. and long 150°25' and 151°5'
W. It includes the upper drainage of the Yentna River and its tributaries,
the best known of which, from the standpoint of gold mining, are Cache,
Mills, Peters, and Long Creeks.
Gold was discovered in this district in 1905 in gravels
in the basins of Peters and Cache Creeks. During the first few years
most of the production was from these placers. In 1911 additional placers
were discovered on Dollar Creek and a few years later on Thunder Creek
and Upper Willow Creek (Capps, 1925, p. 54-55). The district, although
not a tremendous producer, had a steady output, entirely from placers,
and was active through 1957. From 1905 through 1959, about 115,200 ounces
was recorded; data for 1931-46 are not available.
The geology and placer deposits were described by
Capps (1913; 1925, p. 53-61). Intensely folded slates and graywackes
of Mesozoic age compose most of the bedrock. Masses of granitic and
dioritic rocks were intruded into the metasedimentary rocks, and Capps
believed that the numerous gold-bearing quartz veins in the slates and
graywackes were derived from solutions emanating from the cooling intrusives.
Poorly consolidated lignitic sand and clay of Oligocene age (MacNeil
and others, 1961, p. 1904) unconformably overlie the folded older rocks.
The sand and clay are overlain by younger Tertiary gravels.
The placers were derived by weathering and erosion
of the auriferous veins in the metasedimentary rocks, first by Tertiary
streams which deposited the gold in channels in the Tertiary gravels,
then by postglacial streams which reworked the glacial debris and Tertiary
deposits and concentrated gold from these earlier deposits into placers
in the present stream channels. Minable placers occur in the Tertiary
deposits as well as in the Recent gravels.
COPPER RIVER REGION
The elliptical-shaped Copper River
region, which includes a large part of the drainage basin of the Copper
River, is in southern Alaska, bounded by the Alaska Range on the north,
the Chugach Mountains on the southwest, and the Wrangell Mountains on
the northeast. The region lies roughly between lat 61°00' and 63° 10'
N. and long 142°00' and 146°00' W., and it includes the major gold districts
of Chistochina and Nizina.
Gold mining began in this region in
1900 in the Chistochina district, but prospectors were active in the
Copper River country as early as 1898 (Schrader, 1900, p. 421). The
first locations were in auriferous gravels along the Chisna, one of
the main tributaries of the Chistochina River. Productive placers were
discovered along the upper part of the Nizina River and its tributaries
in 1902 (Mendenhall, 1905, p. 118). Minor discoveries were made elsewhere
in the Copper River region about this time, and in 1914 the Nelchina
placers were discovered (Chapin, 1918, p. 59)â€”but the bulk of the
gold production came from the placers of Chistochina and Nizina. In
the Copper River region, especially the Chitina district, copper deposits
were worked extensively by the Kennecott Co. during 1900-38 (Moffit,
1946, p. 93), but they yielded little gold.
From 1900 to 1959 the Copper River
region produced 2,400 ounces of lode gold, 295,000 ounces of placer
gold, and 5,600 ounces of gold undifferentiated as to source - a total
of 303,000 ounces. From World War II through 1959 only a few hundred
ounces per year were produced.
The geology of the region is summarized
here from a more detailed account by Moffit (1938, p. 19-107).
Throughout most of the region the low-lying
areas are blanketed by glacial sands and gravels of Quaternary age.
In the higher areas, a thick succession of bedded rocks range in age
from early Carboniferous to Recent. The oldest rocks consist of schist
and slate associated locally with altered limestone, tuff, and basalt
flows, and they include the Mississippian Strelna Formation and Dadina
Schist and the Carboniferous or older Klutina Series. Overlying these
rocks are layers of lava flows, tuff, volcanic breccia, shale, limestone,
sandstone, and conglomerate of Permian age; these are overlain by the
Nikolai Greenstone, a thick sequence of basaltic lava flows of Permian
and Triassic (?) age.
The post-Triassic Mesozoic rocks in
the Copper River region are not fully understood because of the correlation
problems imposed by variable lithology, exposures in disconnected areas,
and lack of diagnostic fossils. Tuffaceous beds of Middle Jurassic age
occupy a small area near the mouth of the Chitina River. Upper Jurassic
rocks occur in a few places in the central part of the Copper River
basin along the north tributaries of the Chitina River. Along the north
side of Chitina River valley a thick series of bedded sedimentary rocks
of varied lithology is Jurassic or Cretaceous in age. Black shale and
sandstone, conglomerate, and sandy shale considered to be of Early Cretaceous
age overlie Triassic rocks in the Nizina district. The Chugach Mountains,
in the southern part of the region, are underlain by dark slate and
graywacke considered to be Cretaceous or older(?). These are equivalent
to the Valdez and Orca Groups of earlier reports. The Tertiary rocks
are dominantly of volcanic origin and include several thousand feet
of lavas and tuffs interbedded with fresh-water conglomerate, clay,
sandstone, and shale. These rocks compose the higher parts of the Wrangell
The Chistochina district is in the
northwest part of the Copper River basin near the intersection of lat
63°00' N. and long 145°00' W. The drainage area of the Chistochina River,
including the southern foothills of the Alaska Range, roughly determines
the boundaries of this district.
The initial gold discoveries of the
Copper River region were made in this district along the Chisna River
in 1898 by Hazelet and Meals (Moffit, 1944, p. 27). Slate Creek and
Miller Gulch later became the leading gold-producing areas. Production
from this district began in 1900 and continued, though at a diminishing
rate in the later years, to 1942. From 1942 to 1959 the district was
almost dormant, with only sporadic small-scale activity. Total production
from 1900 through 1959 was about 141,000 ounces, all from placers. Production
data from 1931 through 1945 are not complete.
Bedrock in the district consists of
Carboniferous and Permian clastic and sedimentary rocks - predominantly
shale, limestone, conglomerate and some sandstone - and subordinate
volcanic tuffs and lava flows. All the foregoing rocks are cut by dikes
(Moffit, 1944, p. 28). The gold placers were formed by reworking of
glacial debris and occur in bench gravels as well as present stream
The Nizina district is in the eastern
part of the Copper River drainage basin between lat 61°12' and 61°37'
N. and long 142°22' and 143°00' W. This is a placer district along the
Nizina River, a tributary of the Chitina River.
In 1898-99 prospectors were active
in the Chitina River valley and some went up as far as the Nizina area.
Although copper deposits were soon found and quickly developed, it was
not until 1902 that placers rich enough to precipitate a rush were found
on Chititu Creek (Moffit and Capps, 1911, p. 76). The rich deposits
were quickly exhausted and the operators who remained developed previously
known lower grade gravels on Chititu and Dan Creeks. In 1959 these gravels
were still being mined, although on a smaller scale. Total production
through 1959 from the Nizina district was 143,500 ounces of gold; all
but about 60 ounces was from the placers.
The geology of the Nizina district
was described by Moffit and Capps (1911, p. 20-75). Bedrock in the mountain
areas consists for the most part of moderately folded Permian and Triassic(?)
marine sediments and greenstone intruded by laccoliths, dikes, and sills
of quartz diorite porphyry (E. H. Cobb, written commun., 1962). Deposits
of morraine and alluvium blanket the lower slopes of the mountains and
fill the river basins. The source of the gold in the placers is probably
the small quartz veinlets in the black shales that may be related to
porphyritic intrusives in the shales. High bench gravels, remnants of
a deep alluvial valley fill, contain workable deposits, but the richest
placers are in present stream gravels where the gold has been concentrated
by reworking of older deposits (Moffit and Capps, 1911, p. 98-100).
SEWARD PENINSULA REGION
The gold placers of the Seward Peninsula,
in western Alaska, rank second in production among Alaska's placer regions.
The following description of its mining history has been abstracted
from an excellent and detailed account by Collier, Hess, Smith, and
Brooks (1908, p. 13-39).
Placer gold was discovered on Seward
Peninsula in 1855-56 by Baron Otto von Bendeleben, an engineer leading
a party exploring a possible route for a telegraph line. Nothing, apparently,
came of this discovery, for as late as 1897 the Seward Peninsula was
regarded as a wasteland. But about this time the rushes to the Klondike
and the upper Yukon brought in many gold seekers who eventually prospected
the lowly regarded gravels along the streams of Seward Peninsula. Discoveries
were made at Council in 1897, and in 1898 the Nome district was organized.
News spread slowly because of the isolation of this new district, but
by 1899 the rush had begun and, swelled by new discoveries of beach
placers and auriferous bench gravels, it continued through 1900.
In 1900, mining of placers began in
the Fairhaven district in the northeastern part of the peninsula, and
small production was made from discoveries in the Kougarok, Port Clarence,
and Council districts. The Solomon-Bluff district, along the southern
coast just east of Nome, also began producing placer gold in 1900, and
from 1903 to 1907 lode gold was mined from the Big Hurrah mine in this
district. During 1908-59 only very minor amounts of lode gold were produced
from scattered localities on the peninsula.
The Koyuk district was not productive
until 1918 even though for some years gold had been known in the gravels
of the Koyuk River and Alameda Creek, one of its tributaries.
Through the 1950's placer mining continued
to flourish on the Seward Peninsula, although at a somewhat lower rate
than before World War II. The Nome district has been by far the largest
producer; Council, Fairhaven, Solomon-Bluff, Kougarok, Koyuk, and Port
Clarence have produced progressively lesser amounts. Total gold production
of the Seward Peninsula from 1897 through 1959 was 6,060,000 ounces;
all but about 10,000 ounces was from placers.
The geology of the Seward Peninsula
was described by Collier (in Collier and others, 1908, p. 60-110). The
peninsula is underlain chiefly by metasedimentary rocks comprising the
Kigluaik and Nome Groups of early Paleozoic or older age and by unnamed
slates, phyllites, and limestones some of which may be as young as Mississippian.
Collectively these rocks can be considered a sequence of limestone,
biotite gneiss, slate, quartzite, dark phyllite, and schist, cut locally
by small bodies of greenstone and granite. Basalt of Pleistocene age
covers a sizable area in the northeast part of the peninsula. Quaternary
gravels blanket the low-lying coastal areas and occur in all the major
The Council district, in the southern
part of the Seward Peninsula, includes all the drainage area of Golovnin
Bay extending eastward almost to the Tubutulik River.
Although gold had been reported in
the Council area as early as 1865, there was very little excitement
and no mining until after the discoveries of the rich Ophir Creek gravels
in 1896-97 (Smith and Eakin, 1910, p. 343). Production began in 1900,
and the district was still active in 1959. Total production through
1959 was about 588,000 ounces, all from placers. Data for 1931-46 are
Nearly all production came from creek
gravels and bench deposits in the drainage basin of the Niukluk Riverâ€”including
Ophir, Melsing, Goldbot-tom, Mystery, and Elkhorn Creeks (Collier and
others, 1908, p. 238). The following summary of the geology is from
Collier, Hess, Smith, and Brooks (1908, p. 234-235).
The district is underlain by rocks
of the Kigluaik Group and the Nome Group, except in the southeast where
part of a large granite mass forms the bedrock. Schists of the Nome
Group contain numerous small veins and stringers of quartz and calcite,
many of which contain gold along with sulfides. The gold of the placers
is believed to have come from these veins.
The Fairhaven district, about 40 miles
long and 20 miles wide immediately south of Kotzebue Sound in the northeast
part of Seward Peninsula, is bounded roughly by lat 65°40' and 66°10'
N. and long 161°40' and 163°20' W.
Gold was discovered in this district
in 1900 on Old Glory and Hannum Creeks, and although there was no production
that year, the news of the discovery spread through crowded Nome that
winter and prompted a rush to the new district in the spring of 1901
(Moffit, 1905, p. 49). Rich placers, the most productive in the district,
were found along Candle Creek in 1901 (Moffit, 1905, p. 49). The district
produced steadily and was still active in 1957. Total recorded production
through 1959 (data are incomplete for 1931-36) was 379,200 ounces, all
The predominant bedrock in the district
is a series of micaceous, chloritic, and graphitic schists with intercalated
thin limestones believed by Collier (in Collier and others, 1908, p.
65) to be Devonian or Silurian in age. Unaltered conglomerate, sandstone,
and shale unconformably overlie the schists in a few areas. Locally
coal beds are present. Small bodies of granite and quartz diorite intrude
the schists, but their age relations with the unaltered sedimentary
rocks are not clear (Collier and others, 1908, p. 83, 108). Large areas
of the district are covered by sheets of basaltic lava, remnants of
a more extensive cover. The youngest of these flows is Pleistocene;
the age of the older lavas has not been satisfactorily determined (Moffit,
1905, p. 34). Low-lying coastal areas and river valleys are blanketed
by unconsolidated gravels. The gold of the placers was concentrated
from small amounts disseminated in quartz veinlets and stringers in
the schistose country rock. These low-grade lodes have never been productive.
The Kougarok district is in the central
part of the Seward Peninsula between lat 65°10' and 65° 45' N. and long
164°20' and 165°20' W.
The district began producing gold in
1900, after the initial discoveries the previous year sparked a rush
from Nome (Brooks, in Collier and others, 1908, p. 306-307). Because
of its remoteness and its paucity of bonanza-type deposits, the district
developed slowly. Water shortage necessitated the construction of ditches.
By 1906 several ditches were completed and sufficient water for larger
scale operations was assured. Afterward, the Kougarok placers were moderately
productive and were active in 1957. A total of about 150,400 ounces
of gold has been produced from the district, all from placers. This
is a minimum total as data for 1931-46 are incomplete.
The geology of the district was discussed
by Brooks (in Collier and others, 1908, p. 297-298) and is summarized
as follows. The bedrock consists of the Kigluaik and Nome Groups - the
former is predominantly schist and granite; the latter is made up of
a sequence of phyllite, schist, greenstone, and a consistent unit, the
Port Clarence Limestone. The schistose rocks of the Nome Group contain
small auriferous quartz veinlets and stringers which appear to be the
source of the placer gold that has been concentrated into minable quantities
in present stream gravels, bench gravels, and flood-plain gravels. The
lodes themselves are not of economic value.
PORT CLARENCE DISTRICT
The Port Clarence district, an area
of about 2,000 square miles on the west end of the Seward Peninsula,
has produced small amounts of placer gold from the Bluestone and Agiapuk
River basins and from a few streams that drain into Grantley Harbor.
The district was prospected as early as 1898, and by 1903 an estimated
$200,000 in gold had been produced (Collier and others, 1908, p. 269).
Total recorded production through 1959 is about 28,000 ounces, all from
placers, but 1931-46 production is not recorded. Since World War II
there has been only small-scale activity.
The district is underlain by schist,
limestone, and small intrusive bodies comprising the Kigluaik and Nome
Groups of early Paleozoic or older age, and by Devonian (?) slate and
Carboniferous (?) limestone. Stocks and dikes of granite and greenstone
intrude the metasedimentary rocks. Quaternary gravels contain gold placers
which are restricted in general to areas underlain by rocks of the Nome
Group. These rocks seem to contain more auriferous veinlets and stringers
than the other bedrock types. The foregoing account is from Collier,
Hess, Smith, and Brooks (1908, p. 268-281).
The camps of Bluff and Solomon, an
area enclosed by lat 64°30' to 65°00' N. and long 163°30' to 164°30'
W., are combined here.
Gold was first discovered in this district
in 1898 in gravels along the Casadepaga River, a tributary of the Solomon
River. The following year other placers were found along the Solomon
and on the beach of the mouth of Daniels Creek in the Bluff camp (Brooks,
in Collier and others, 1908, p. 288). The beach placers were exhausted
in about a year, but more extensive placers were found along Daniels
Creek and along Hurrah and Shovel Creeks in the Solomon camp. These
were worked by dredges and hydraulic methods (Smith, 1910, p. 139).
The only important gold-quartz mine on the Seward Peninsula was the
Big Hurrah in the Solomon camp, which was active from 1900 to 1937.
A total of 251,000 ounces of placer
gold has come from the Solomon-Bluff district not including production
from 1931 to 1946 for which records have not been found. Lode production
was 9,375 ounces; all was presumably from the Big Hurrah mine. Total
production recorded for the district is 260,375 ounces. No production
was recorded from 1937 through 1959.
The district is underlain by rocks
belonging to the lower part of the Nome Group of early Paleozoic or
older age. These are a series of schist, slate, and limestone. The metasedimentary
rocks were intruded by basic igneous rocks, were later altered to schist
and greenstone, and were finally intruded by basalt (Smith, 1910, p.
49-137). Unconsolidated deposits consist of coastal plain deposits,
stream gravels, and high-level gravels.
The lode deposit at the Big Hurrah
mine consists of several quartz veins in a dense, hard, quartzitic,
graphitic schist. There is a noticeable absence of sulfides; the minerals
consist almost exclusively of native gold in quartz (Smith, 1910, p.
The gold in the placers, which consist
of stream and beach gravels in the Bluff area and stream and bench gravels
in the Solomon area, was derived from disseminations and veinlets in
rocks of the Nome Group, particularly in the schist and in the vicinity
of schist-limestone contacts (Smith, 1910, p. 214-216).
The vast Yukon region encompasses the
entire drainage basin of the Yukon River in Alaska. It has the shape
of a truncated wedge extending across central Alaska. The region is
narrower (80 to 100 miles wide) along the west coast of Alaska at the
mouth of the river and wider (200 to 300 miles) along Alaska's eastern
border, where it includes the basins of the Yukon and one of its main
tributaries, the Tanana. This has been by far the most productive of
all the gold-producing regions, with a recorded total through 1959 of
12,282,250 ounces, most of it from placers.
Goodrich's detailed account (in Spurr
and Goodrich, 1898, p. 103-131) of the early explorations, the discovery
of gold, and the development of the first mining districts is the source
of much of the material presented here.
The Yukon region had been traversed
rather thoroughly after the 1840's by explorers and traders intent on
establishing new posts and opening new country for the fur trade. A
lively competition which developed among the Russians, the Hudson Bay
Co., and the Americans was terminated by the purchase of Alaska by the
In the 1860's small quantities of gold
had been found at several localities in the Yukon basin, but credit
for the discovery that led to intensive prospecting goes to George Holt,
who made several trips to the Yukon in the 1870's and returned with
glowing, if not entirely veracious, tales of gold in the interior. In
1881 a few prospectors panned some gold along the Big Salmon River,
one of the tributaries of the Yukon River in the Yukon Territory, Canada.
A year later, prospectors working up the Yukon from its mouth found
gold in considerable quantities near what is now Rampart, in central
Alaska. Discoveries in the 1880's along the boundary between Alaska
and Canada in the Fortymile River area were developed rapidly, and by
1893 more than 300 men were working the gravels. Birch Creek in the
Circle district next attracted attention and it soon rivaled the Fortymile
district. Between 1890 and 1895 gold-bearing gravels were found along
the Koyukuk River and additional discoveries were made in the Rampart
area and in the adjacent Hot Springs district.
In 1902 gold was discovered in the
Fairbanks district (Prindle, 1904, p. 64) which in the succeeding years
developed into the leading producer in Alaska. The Fairbanks discoveries
stimulated prospecting to the south in the foothills of the Alaska Range,
and placers were found in the Bonnifield country in 1903 and the Kantishna
district in 1906 (Prindle, 1907, p. 205).
At about the same time, commercial
quantities of gold were found several hundred miles to the west in the
gravels of the upper valley of the Innoko River and this led to discoveries
on the adjacent Iditarod River. In about 1910 placers were found along
Long Creek in the Ruby district, about 70 miles east of Koyukuk (Mertie
and Harrington, 1924, p. 88, 89, 101). One of the most recently discovered
placer districts in the Yukon region is the Tolovana district situated
along the Tolovana River, a tributary which joins the Tanana River about
100 miles west of Fairbanks. Mining of these placers began in 1915 (Brooks,
1916, p. 201).
Most of the placer districts of the
Yukon, basin remained active after World War II,, through 1959, though
production decreased because of the constantly rising mining costs especially
Only two districts - Fairbanks and
Nabesna - have had any significant lode production, but this is dwarfed
by the placer output. The Yukon basin has yielded a total of 12,282,250
ounces of gold, of which 10,776,460 ounces is from placers, 305,560
ounces is from lode deposits, and 1,200,230 ounces is undifferentiated
but presumably from placers. It may seem strange that from such a large
region so few commercial vein deposits have been exploited; however,
several factors must be considered in an analysis of this imbalance.
First, the placers are amenable to large-scale dredging methods which
means that low-grade material can be mined even at present high costs.
Secondly, the remoteness of the areas containing the lode deposits demands
large tonnages of high-grade ores for profitable mining.
It is difficult to summarize the geology
of a region as large as the Yukon drainage basin, especially in view
of the fact that the region has not been completely mapped and the areas
that are mapped were done at different scales at different times and
by numerous individuals. The upper part of the basin, the Yukon-Tanana
area, was mapped first by Spurr (in Spurr and Goodrich, 1898) and then
by Mertie (1937), but that part of the basin from the junction of the
Yukon and Tanana to the mouth of the Yukon has been mapped in small
parcels by individuals investigating only certain districts.
In the upper part of the basin, stratified
rocks ranging in age from Precambrian to Recent are exposed. Representatives
of every period except Jurassic are present (Mertie, 1937, p. 44-46).
Mesozoic and Tertiary granitic intrusive rocks are the most important
members of the igneous family in this area, and it is believed that
the metalliferous ore deposits are related to them (Mertie, 1937, p.
Farther downstream, in the Ruby area,
greenstones and undifferentiated metamorphic rocks of Paleozoic age
and older are the predominant country rocks (Mertie and Harrington,
1924, p. 12). In the Innoko and Iditarod districts, which may be considered
the lower reaches of the Yukon, Mesozoic sedimentary rocks, chiefly
Cretaceous in age, compose most of the country rock. These are inter-layered
locally with basic igneous rocks. Granitic intrusions make up the mountain
areas, and rhyo-lite dikes are scattered throughout the areas (Eakin,
1913, p. 295).
Throughout the Yukon basing large areas
are covered with fluvial deposits that form flats tens of miles wide.
The entire region has a complex geomorphic and structural history, much
of which is fairly recent in age, but not enough work has been done
in the region to interpret the many anomalous features of the present
drainage (Mertie, 1937, p. 237).
The Bonnifield district is between
lat 63°30' and 64°50' N. and long 145°40' and 149°20' W. It extends
from the Tanana flats on the north to the north slope of the Alaska
Range on the south, and it is bounded on the west and east by the Nenana
and Delta Rivers, respectively.
The first gold was mined from the gravels
of Gold King Creek in 1903. During the early years there were high hopes
that the Bonnifield would become a major district, but only small amounts
of gold were produced annually, and after 1949 the district was idle.
Total production through 1959 was about 36,600 ounces, all from placers.
The geology, as outlined by Capps (1912,
p. 17-19), is as follows. The oldest rocks in the district are metasedimentary
rocks of Precambrian or early Paleozoic age - the Birch Creek Schist,
consisting of quartz and mica schist, phyllite, and quartzite. Mertie
(1937, p. 46) considered the Birch Creek to be Precambrian in age. The
Birch Creek Schist is overlain by quartz-feldspar schists forming the
Totatlanika Schist of Silurian or Devonian age. A sequence of Tertiary
sediments beginning with Eocene fresh-water deposits unconformably overlies
the schists. The freshwater deposits are followed by the Nenana Gravel
of middle Miocene to early Pliocene age (MacNeil and others, 1961, p.
1806) and Pleistocene and Recent glaciofluvial deposits. The schists
are highly contorted, and as the Alaska Range rose in Tertiary time
the Tertiary beds were subjected to considerable folding and faulting
immediately after their deposition. Intrusive rocks of granitic to dioritic
composition cut the schists at various localities. These bodies are
older than Eocene and younger than Silurian or Devonian (Capps, 1912,
The placer deposits are in the foothills
between the Tanana Flats to the north and the high slopes of the Alaska
Range to the south. Present streams have cut through valleys previously
filled with alluvium and have reconcentrated and redeposited the detrital
gold of the older alluvium.
The Chandalar district, between lat
67°00' and 68°10' N. and long 147°00' and 150°00' W., includes the upper
drainage of the Chandalar River.
The Chandalar district, which began
producing placer gold in 1906, is one of the small producers of the
Yukon basin. Total placer production through 1959 was 30,708 ounces.
Cobb (1962) indicated small but undisclosed lode production from the
district. Lode deposits, which have been known in the district for many
years, have recently received renewed attention. In 1961 the Little
Squaw Mining Co. reported blocking out an ore body worth $1,013,000
in gold (Mining World, 1961).
The geology given here is generalized
from a more detailed account by Mertie (1925, p. 223-252). Schists,
resembling the Birch Creek Schist, of Precambrian or early Paleozoic
age are the oldest rocks in the district and are found in the southern
part. Other schists and phyllites of early Paleozoic age compose the
bedrock in the central part of the district, north of the area underlain
by Birch Creek (?) Schist. Silurian limestone and dolomite and Devonian
slate occur still farther north. In the southwest corner, Devonian or
Mississippian rocks unconformably overlie the schists, and a small patch
of Upper Cretaceous sandstone caps the sequence. Igneous rocks in the
district consist of granite, granodiorite, and basic lavas, that range
in age from Late Silurian or Early Devonian to Tertiary.
The schists contain numerous small
auriferous quartz veins and stringers that no doubt were the source
of the gold in the placers. Both preglacial and postglacial gravels
have been productive.
The Chisana district is between lat
61° 55' and 62°20' N. and long 141°40' and 142°35' W., in the drainage
area of the Chisana River, a tributary of the Tanana River.
Gold lodes were known in this area
before 1910, but were never developed; then in 1913 placer discoveries
along Bonanza Creek started a stampede to the district (Capps, 1916,
p. 89-92). The placers, however, were relatively small, and efforts
to find and develop lode deposits were unsuccessful. Small amounts of
placer gold were produced up to World War II, but since then the output
has been insignificant. Total production from 1913 through 1959 was
44,760 ounces, all from placers.
The rocks of the district range in
age from Devonian to Recent (Capps, 1916, p. 29-31). The oldest rocks
are black shale, basic lava, and pyroclastic of Devonian age which are
overlain by a great thickness of Carboniferous lava, tuff, breccia,
agglomerate, and some limestone and shale. Shale and graywacke of Mesozoic
age are faulted against the older rocks along an east-west line. Several
small patches of Tertiary sediments unconformably overlie the Paleozoic
rocks, and in the stream valleys considerable areas are covered with
glacial debris and stream deposits interbedded with lava flows. Granitic
intrusions cut the Devonian and Carboniferous rocks but the exact age
of the igneous rocks is not known (Capps, 1916, p. 84-85).
Most of the placers occur in the area
of Carboniferous pyroclastic rocks and the granitic intrusions. Capps
(1916, p. 96-98) believed that the gold of the placers was eroded from
veins in these Paleozoic rocks near their contact with the intrusives
and that the present placers are a product of several previous reworkings
of Tertiary auriferous gravels, first by streams, then by glaciers,
then by the present streams reworking the glacial deposits.
The Circle district is between lat
65° 15' and 66°00/ N. and long 144°00' and 146°00' W.
This is one of the older districts
of the region, gold having been discovered along Birch Creek in 1893
(Prindle, 1906, p. 20). Production began the following year and was
continuous through 1957. Hydraulic methods were used on nearly all productive
streams, particularly along Mastodon Creek. Total production through
1959 was 705,660 ounces, all from placers.
The rocks, as summarized from Mertie
(1932, p. 158-161), consist of schist, clastic sedimentary rock, limestone,
and granitic rocks ranging in age from Precambrian to Mesozoic. Pleistocene
and Recent unconsolidated deposits complete the sequence.
The Birch Creek Schist, the oldest
rock, is of Precambrian or early Paleozoic age. Next youngest are lower
Paleozoic metamorphic rocksâ€”quartzite, phyllite, and slateâ€”together
with graywacke, arkose, limestone, and chert. The Crazy Mountains in
the central part of the district are underlain in succession by Silurian
or Devonian limestones, basic flows and sedimentary rocks of the Rampart
Group of Early Mississippian age, and by a later Missis-sippian chert
formation. Several small bodies of granite are intrusive into all the
foregoing rocks, and the placer deposits are in the vicinity of the
intrusive bodies. Alluvial deposits in the Circle district represent
several erosional periods during Pleistocene and Recent time.
The Eagle district is between lat 64°
35' and 65° 15' N. and long 141°00' and 142°40' W., along Seventymile,
American, and Fourth of July Creeks, all tributaries that enter the
Yukon River near Alaska's eastern boundary.
Placer gold was first found in 1895
along American Creek, and production began the following year (Mertie,
1938, p. 190). Although it attracted few miners, the Eagle district
maintained a small annual production even through the difficult post-World
War II years. Production data before 1906 cannot be found and was probably
reported under some other district. Total recorded production for the
Eagle district from 1906 through 1959 is 40,220 ounces, all from placers.
The district is underlain in the southwest
by a large mass of granite of Late Jurassic age that has intruded and
thrust upward a series of Precambrian and Paleozoic sedimentary rocks
that are now exposed in northwestward-trending bands in the central
and northern parts of the district. Lower Cretaceous marine rocks are
exposed in the northern part of the district and these are succeeded
by a thick series of freshwater deposits of Late Cretaceous and Eocene
age (Mertie, 1930, pi. 12). Post-Eocene uplift caused much of this covering
to be removed. Unconsolidated deposits of sand and gravel of Pleistocene
and Recent age are in the stream valleys. These sediments reflect a
complex geomorphic cycle involving local glaciation, climatic changes,
and changes in base level (Mertie, 1930, p. 147-148).
The gold placers are in present stream
gravels. The gold in these deposits came originally from small veins
related to the granitic mass in the southwest part of the area, but
much gold also came from ancient placers in the Upper Cretaceous and
Eocene elastics (Mertie, 1930, p. 161-162).
The Fairbanks district, about 300 square
miles between lat 64°40' and 65°20' N. and long 147°00' and 148° 10'
W., has produced more gold than any other district in Alaska. It is
predominantly a placer district, although it also ranks high among the
Fairbanks was slow to develop. Placer
gold was known in the area as early as 1878 (Mertie, 1937, p. 4), but
the active districts of Fortymile, Rampart, and Circle kept all but
the most restless away from the Fairbanks area. In 1901 the town of
Fairbanks was founded as a trading post, not as a consequence of gold
mining (Prindle and Katz, 1913, p. 86). The following year some workable
placers were found along Pedro Creek. This discovery brought a rush
of miners and prospectors to the district, most of whom became discouraged
and left after learning that the rich, easily accessible placers were
few and that the large, lower grade deposits were buried and required
processing large volumes of material with special machinery. Large investments
were needed to purchase and construct hoisting machinery, large dredges,
and machinery for thawing the frozen overburden. But gradually, as the
obstacles were overcome, it was found that the buried gravels could
be mined profitably, and the district prospered as the dredges chewed
through huge reserves of auriferous gravels on Dome, Ester, Vault, Cleary,
and Chatanika Creeks. Production continued at a high level even after
World War II, but in 1959, activity began to diminish. The Fairbanks
Daily News-Miner reported (Sept. 15, 1959) that gold dredging was gradually
ceasing in this area. Two dredges were closed in 1959 and a third was
transferred to the Fortymile district.
Interest in lode mining began after
the placers were developed. Small-scale operations were under way in
1910 in Skoogy Gulch and upper Cleary and Fairbanks Creeks (Hill, 1933,
p. 51). The peak of lode mining was reached just before World War II.
The Pedro Dome and Ester Dome areas contain the most productive lode
The total gold production of the Fairbanks
district through 1959 was 7,464,167 ounces - 7,239,696 ounces from placers,
224,471 ounces from lodes.
The Birch Creek Schist, of Precambrian
or early Paleozoic age, underlies most of the district (Hill, 1933,
p. 41). This includes a variety of rock types, among which quartz schist
and quartzite are dominant. Masses of crystalline limestone are present
locally. Small bodies of biotite granite and quartz diorite believed
to be of Mesozoic age (Hill, 1933, p. 43) intrude the Birch Creek. In
the northeast corner of the district is a small patch of Tertiary sandstone
and conglomerate, and in the same general area are a few small isolated
areas of Tertiary basalt (Hill, 1933, p. 42-43).
The lode deposits of the Fairbanks
district are fissure veins in the Birch Creek Schist in the vicinity
of bodies of intrusive rock. The trends of both the veins and intrusives
seem to be controlled structurally, but the trends are not consistent
throughout the district (Hill, 1933, p. 63-64). All the major intrusives
trend eastward; the veins in the Pedro Dome area also trend eastward,
but the veins in the Ester Dome area trend more northward. The veins
consist of quartz with small amounts of the sulfides arsenopyrite, pyrite,
sphalerite, jamesonite, and stibnite, and free gold which is associated
either with quartz or with the sulfides. Cervantite is widespread as
an oxidation product of stibnite, and its yellow-green stain is a guide
to high-grade gold ore in this district (Hill, 1933, p. 64-73).
The gold placers occur along stream
valleys in unconsolidated gravels. The most productive layer is normally
a few inches to 8 feet above the bedrock ; the bedrock from 1 foot to
several feet below the gravel is usually gold bearing. A thick mantle
of barren material consisting of sands, clays, and muck covers the deposits
(Prindle and Katz, 1913, p. 92-98).
The Fortymile district, between lat
64°00' and 64°30' N. and long 141°00' and 142°20' W., along the international
boundary, includes the upper drainage of Fortymile River, one of the
Yukon tributaries that joins the main stream in Canada. It is one of
the oldest placer areas in the Yukon region and had uninterrupted output
According to Mertie (1938, p. 157),
gold was discovered in the district in 1886, but Smith (1933, p. 96)
listed small production beginning in 1883. Discoveries of rich stream
placers in 1893 in the Sixtymile River area, across the international
boundary, drew many prospectors to the Fortymile district as well, and
in a relatively short interval all the major gold-producing grounds
in the Forty-mile district were found. The placers of Dome, Wade, and
Chicken Creeks were all discovered during the 1890's (Mertie, 1938,
p. 157). Large-scale mining methodsâ€”dredge and hydraulicâ€”have been
used with success, which is probably why the district was still active
Total recorded gold production of the
Fortymile district through 1959 was about 400,000 ounces, all from placers.
The most abundant country rock of the
district, according to Mertie (1938, p. 148), is the Birch Creek Schist,
but locally other rocks are present. In the Chicken Creek and Franklin
Creek areas granite is exposed (Mertie, 1938, p. 171, 182). Small patches
of Tertiary conglomerate, shale, and sandstone are known in the Chicken
Creek and Napoleon Creek areas, and some lower Paleozoic greenstone
and limestone is exposed along Napoleon Creek (Mertie, 1938, p. 184).
Basalt, gabbro, and diabase, younger than the granite, are found in
the central part of the Chicken Creek basin.
The productive deposits are in gravels
of Pleistocene to Recent age. There are also ancient placers in the
Tertiary deposits, but none of these contain gold in commercial quantities.
On the other hand, these Tertiary deposits, where eroded, contributed
their gold to the younger deposits. Quartz veins related to the granite
intrusives are the ultimate source of the gold, according to Mertie
HOT SPRINGS DISTRICT
The Hot Springs district is between
lat 65°00' and 65°20' N. and long 149°40' and 151°20' W. The drainages
of Baker, Sullivan, and American Creeks are its major placer areas.
Gold-bearing gravels were discovered
in 1898 on Baker and Eureka Creeks by a group of New Englanders known
throughout the area as the "Boston Boys" (Mertie, 1934, p. 165-166).
When the party returned in 1899 to the new settlement of Rampart, news
of their discoveries leaked out and caused a rush to the Hot Springs
area. The first production reported was in 1904 (Smith, 1933, table
facing p. 96) ; a town was built a few years later (Mertie, 1934, p.
The district maintained a steady output
since mining began and was still active in 1959. Opencut, drifting,
and hydraulic methods have been used in the mining. Total production
through 1959 was 447,850 ounces, all from placers.
As the Hot Springs and Rampart districts
are separated by only a narrow drainage divide, their geology can be
Consolidated sedimentary rocks that
range in age from pre-Ordovician to Tertiary and include sandstone,
shale, conglomerate, chert, limestone, and coal-bearing rocks compose
the bulk of the bedrock in these two districts (Mertie, 1934, p. 172-173).
These are intruded locally by granite of Tertiary age.
Eakin (1915, p. 239) noted that the
placers of the Hot Springs district were of several types - bench deposits,
reworked bench deposits, irregular discontinuous bodies of auriferous
gravel called "spots," and normal stream gravels containing pay streaks.
The gold of the placers was deposited
during early and late Tertiary from lodes in and adjacent to granitic
intrusives (Mertie, 1934, p. 223).
The Iditarod district, between lat
62° 10' and 63°00' N. and long 157°30' and 158°30' W., along the upper
drainage of the Iditarod River and its tributaries, ranks second among
the gold-producing districts in the Yukon basin.
Gold was discovered in 1908 along Otter
Creek, a tributary of the Iditarod River (Maddren, 1911, p. 238). Despite
its remoteness, the district developed, and in 1910 production was reported
at $500,000 (Smith, 1933, table facing p. 96). Productive gravels also
were found on Flat and Willow Creeks. The placers have been mined by
dredges, mechanical scrapers, and hydraulic equipment (Mertie and Harrington,
1924, p. 110). Total gold production through 1959 was 1,297,500 ounces;
nearly all production was from placers.
The underlying bedrock of the district,
as described by Mertie and Harrington (1924, p. 12-82), consists dominantly
of sandstone, shale, and conglomerate of late Cretaceous and Eocene
age. In the western part of the district, west of the Iditarod River,
undifferentiated metamorphic rocks of Paleozoic and Precambrian age
are exposed; in the central part there are a few small stocks of quartz
monzonite and basic intrusives. Unconsolidated deposits of sand, gravel,
and silt of Pleistocene and Recent age are in the stream valleys.
Placers are of two types - residual
and stream (Mertie and Harrington, 1924, p. 111-115). The stocks of
monzonite, which are sheared and mineralized, are the source of the
gold for each type.
The Innoko district, in the upper drainage
area of the Innoko River between lat 62°50' and 63°15' N. and long 156°10'
and 156°50/ W., lies immediately northeast of the Iditarod River. The
Beaver Mountains form the drainage divide between the Innoko and Iditarod
Gold was discovered in the gravels
of Ganes Creek in 1906, and despite its remoteness the new camp attracted
permanent settlers (Maddren, 1911, p. 236) who began gold production
in 1907 that continued uninterrupted through 1957. Most of the mining
was in the Ophir, Spruce, Little, Ganes, and Yankee Creek areas (Maddren,
1911, p. 246). The Innoko is a placer district and through 1959 produced
a total of 518,565 ounces of gold. Most of the placers are in the gravels
of the present streams or in bench deposits.
Argillaceous beds of Late Cretaceous
and Eocene age underlie most of the Innoko district, except for a small
area in the northeastern part where several small bodies of quartz monzonite
and basic intrusives cut the sedimentary rocks (Mertie and Harrington,
1924, p. 30, 62, 69, pi. 4).
The Kantishna district is an area of
about 4,500 square miles, between lat 63°25' and 65°00' N. and long
149°00' and 151°10' W., that includes part of the Alaska Range foothills
on the south and part of the Tanana lowlands on the north. It is bounded
on the east by the Nenana River and on the west by the western tributaries
of the Kantishna River.
The Tanana River valley became well
populated by miners and prospectors during the early part of the Fairbanks
rush, and soon the rich gravels in the Kantishna district were found.
In 1904 gold was found along Toklat River and the following year a flood
of hopeful gold seekers left Fairbanks for the new district (Capps,
1919, p. 75). Soon several thousand people swarmed into the area, nearly
all streams were staked, and several towns were built. It soon became
apparent that the deposits, though rich, were shallow and of small area,
so that a dismal exodus began and the population of the district quickly
dwindled to about 50 (Capps, 1919, p. 76). Those who remained were able
to maintain small production from the placers, and the district was
still active on that scale in 1957. In 1904-5 lode deposits of lead-silver
and antimony were found, and in 1921 gold, copper, and mercury lode
deposits were discovered. The antimony deposits were worked sporadically
during 1936-55, but the other lode deposits never achieved any significance
(Reed, 1961, p. 27-28).' Total gold production from the district from
1905 through 1957 was 45,925 ounces, all from placers. No activity was
reported in 1958-59.
The oldest rock in the district is
the Birch Creek Schist of Precambrian age (Wells, 1933a, p. 343). This
schist is succeeded by younger schists, phyllites, and gneisses, composing
the Totatlanika Schist of pre-Devonian age and the Tonzona Group of
Devonian or Silurian age. Pre-Tertiary greenstone, Mesozoic limestone,
a sequence of Tertiary fresh water sediments, tuffs, and flows, and
Quaternary glacial, glaciofluvial, and fluvial deposits complete the
sedimentary column in the district (Capps, 1919, p. 22-23). The pre-Tertiary
and lower Tertiary rocks have been deformed into east-trending folds
parallel to the axis of the Alaska Range to the south of the district
(Capps, 1919, p. 22).
The productive placers of the district
are along the streams that radiate outward from the higher parts of
the Kantishna Hills. The gold was believed by Capps (1919, p. 79) to
be derived from erosion of small quartz veins that cut the Birch Creek
The Koyukuk district, between lat 67°00'
and 68°00' N. and long 149°00' and 150°50' W., drained by the north,
middle, and south forks of Koyukuk River, is often considered to be
one of the most northerly in the world.
Some time between 1885 and 1890 placer
gold was first found in this district on the sand bars along the Koyukuk
River. Maddren (1913a, p. 76) reported that by 1898 at least $4,000
in gold had been mined from them; however, Smith (1933, p. 96) did not
report production from the Koyukuk district until 1900. Nearly all the
upper reaches of the Koyukuk tributaries have been prospected, and the
results have been rewarding. The district was still active in 1959,
though only on a small scale. Total production from the district through
1959 was about 278,000 ounces, all from placers. Promising lode deposits
of gold have not been found in this district.
The most abundant bedrock in the district
is the ubiquitous Birch Creek Schist of Precambrian or early Paleozoic
age. The schist is exposed in two belts - one in the southern part of
the Endicott Mountains and the other in the Hodzana highland area, between
the Yukon River and the Koyukuk valley. Numerous dikes and small intrusives
of granitic composition, probably Mesozoic in age, cut the schist (Maddren,
1913a, p. 34-36). Exposed in the central and northern parts of the district
are two sequences of Paleozoic rocks: one is of Devonian (?) age and
consists of greenstone, slate, chert, and limestone; the other is a
section of crystalline limestone and mica schist of Carboniferous (?)
age. Underlying the western part of the district are Mesozoic sedimentary
rocks represented by Cretaceous limestone and calcareous sandstone inter-bedded
with basic flows and pyroclastics (Maddren, 1913a, p. 50-55).
Pleistocene gravel covers large areas
in the district, including all the major stream valleys. Recent deposits
include gravels along present stream courses.
The placer deposits are in present
stream gravels and bench gravels; some of them are buried. Maddren (1913a,
p. 83) considered that the gold in the placers was derived from the
Birch Creek Schist. Auriferous pyrite occurs in carbonaceous phyllite
facies and free gold is found in quartz veinlets and stringers that
cut the micaceous quartz schist facies. The gold was transported by
streams and glaciers and later concentrated by further stream action
into the placer deposits.
The Marshall district is between lat
61°40' and 62°00' N. and long 161°30' and 162°10' W., along the lower
During the early days, just after the
discoveries at Nome, the port of St. Michael was the terminus and supply
center for prospectors embarking on trips up the Yukon River or along
the coastline of the Seward Peninsula. A portage to the upper Anvik
River, one of the Yukon tributaries, greatly shortened the trip to the
goldfields at Dawson and elsewhere on the upper Yukon by eliminating
travel along several hundred miles of meanders on the lower Yukon River.
Thus, except for a few itinerant prospectors and traders, the Marshall
district was rather thinly settled and sparsely prospected.
In 1913, however, gold was discovered
on Wilson Creek in the Marshall district (Harrington, 1918, p. 56).
The usual rush followed. Additional placers were found on Willow Creek,
and the first production was in 1914. Lode deposits were found in 1914,
and a small shipment was made that same year (Harrington, 1918, p. 57).
The quartz veins did not warrant extensive development; at any rate,
lode production for the district is unrecorded.
After the first few years of near-bonanza
placer production, activity slackened, was rejuvenated briefly in the
late 1930's, then declined after World War II. In 1957 there was only
small-scale activity in the Marshall district. Total recorded gold production
through 1957 was 113,200 ounces, all from placers. The district was
idle in 1958 and 1959.
Much of the bedrock in the Marshall
district is greenstone and intercalated sedimentary rocks of Carboniferous
age (Harrington, 1918, p. 22-26). These rocks are cut by several stocks
and dikes of granite, quartz diorite, and dacite of possible Jurassic
or Tertiary age (Harrington, 1918, p. 45-46). Cretaceous sandstone and
argillite, somewhat metamorphosed, occur adjacent to the greenstone
throughout much of the district. The most abundant rock type exposed
in the district is the unconsolidated material deposited during Quaternary
time by the debris-laden streams issuing from the huge glaciers of the
interior of the Yukon River basin (Harrington, 1918, p. 36-44).
The Nabesna district is between lat
62° 10' and 62°30' N. and long 142°40' and 143°10' W.
Gold had been known in this district
since 1899, but there was no significant production until 1931 when
the first shipments were made from the Nabesna mine, the lone producer
of the district. Credit for the discovery is given to a bear who exposed
the moss-covered outcrop of the principal vein while digging out a gopher.
The property was developed by C. F. Whithan, who formed the Nabesna
Mining Co. in 1929 and began shipping ore in 1931 (Wayland, 1943, p.
176-177). By 1939, much of the vein was worked out and in 1940 production
halted. Additional exploration and development work in the district
apparently was unsuccessful for there has been no further production
reported. In its brief history the Nabesna district produced about 63,300
ounces of gold, all from lodes.
The rocks in the vicinity of the mine
consist of the Nabesna Limestone of Late Triassic age and basaltic lavas
and shale of possible Permian age (Wayland, 1943, p. 177). A few small
bodies of quartz diorite cut the limestone. The thick Wrangell Lava
of Tertiary and Quaternary ages unconformably overlies these rocks.
Moraine and fluvial sediments of Quaternary age are found in all the
The ore bodies are in contact-metamorphosed
limestone near the largest of the quartz diorite intrusives (Wayland,
1943, p. 183-191). Ore deposits are of three types: bodies of magnetite
with pyrite, calcite, and some gold; veins and bodies of pyrrhotite
with minor pyrite and gold; and gold-bearing pyrite veins in tactite
or along intrusive contacts. The third type is the most important and
has accounted for most of the production of the Nabesna mine.
The Rampart district, between lat 65°15'
and 65°40' N. and long 149°40' and 150°40' W., joins the Hot Springs
district on the north.
Gold was discovered in the gravels
of Minook Creek and Hess River and their tributaries in 1882, but for
the succeeding 10 years nothing was done to develop the placers. In
the early 1890's more discoveries were made and finally in 1896 the
first mining was done on Little Minook Creek (Hess, in Prindle and Hess,
1906, p. 26). Smith (1933, table facing p. 96), however, does not report
any production until 1904. The district reached its peak of activity
before 1910; after that time, production decreased, and in the 1950's
only a few hundred ounces per year were mined. Total gold production
through 1959 was 86,800 ounces from placers. There are no workable lode
deposits in the district.
The geology of the district, as summarized
by Mertie (1934, p. 172-173), is chiefly the same as that of the Hot
Springs district. Consolidated sedimentary rocks - which range in age
from pre-Ordovician to Tertiary and include sandstone, shale, conglomerate,
chert, limestone, and coal-bearing rocks â€”compose the bulk of the
bedrock. These are intruded locally by granite of Tertiary age. The
major placers are along Minook Creek and its tributaries and along Quail
Creek, one of the tributaries of Troublesome Creek.
Several prominent stream terraces containing
low-grade gold deposits occur along the Minook Creek valley, but most
production has come from gravels at present stream levels along Little
Minook Creek (Mertie, 1934, p. 181).
The Ruby district is between lat 63°40'
and 64° 45' N. and long 154°40' and 156°20' W.
The first discoveries of gold in this
district were made in 1907 along Ruby Creek (Mertie, 1936, p. 144).
These placers were soon exhausted, but other discoveries in 1910 along
Long Creek and in 1912 along Poorman Creek kept the district flourishing
(Mertie, 1936, p. 145, 159). Underground drifting, sluicing, and hydraulic
methods have been used to mine the gravels. Although production decreased
somewhat in recent years, the district was still producing substantially
through 1959. Total gold production through 1959 was 389,100 ounces,
all from placers.
Undifferentiated metamorphic rocks,
including schist, phyllite, slate, quartzite, chert, and limestone,
are mainly of Paleozoic age and are the predominant bedrock types in
the Ruby district (Mertie and Harrington, 1924, p. 12). A complex of
greenstone derived from basic igneous rocks, beÂ¬lieved to be Mississippian
in age (Mertie and Harrington, 1924, p. 59), is exposed throughout the
district. A few granite stocks of Mesozoic(?) age intrude both the Paleozoic
rock units. The generalized structure is an anticline trending northeast
and plunging to the southwest.
Numerous quartz veins are in the country
rocks; some undoubtedly contain gold and could be regarded as the source
of the gold in the placers. The distribution of the placers, however,
does not directly coincide with areas of abundant veins, so that no
clear relationship is apparent (Mertie and Harrington, 1924, p. 121).
Nearly all the placer deposits are buried discontinuous bodies that
occur mostly in fairly wide valleys. They were formed by streams older
than those now occupying the valleys (Mertie, 1936, p. 144).
The Richardson (or Tenderfoot) district
is between lat 64° 15' and 64°25' N. and long 146°00' and 146°40' W.,
about 60 miles southeast of Fairbanks, along the Tanana River.
This is a little-known district, about
which only a few brief accounts have been written. According to Prindle
(in Prindle and Katz, 1913, p. 141) gold was discovered in the gravels
of Tenderfoot Creek in 1905 and for the following 4 years the gold production
was probably "$300,000 or $400,000 annually." Smith (1933, table facing
p. 96), however, reported a much more conservative figure. Productive
deposits also were found along Buckeye and Democrat Creeks. Activity
declined after the initial boom period and in recent years the production,
which is low, has been combined with that of the Fairbanks district.
Total recorded production for the district through 1959 was 64,300 ounces,
all from placers.
Prindle (in Prindle and Katz, 1913,
p. 140-141) noted that the bedrock in the district is Birch Creek Schist
of Precambrian age (Mertie, 1937, p. 46). Numerous small quartz veins,
some of which carry gold and sulfides, occur in the schist. Just west
of the district are some large granitic masses (Prindle, in Prindle
and Katz, 1913, p. 140-141). The placers are along present streams in
The Tolovana district is between lat
65° 20' and 65°45' N. and long 147°50' and 149°00' W. in the upper drainage
of the Tolovana River, a tributary of the Tanana.
Brooks (1916, p. 201) reported that
placer gold had been found in this area as early as 1892 but that no
interest was aroused until 1914, when placers along Livengood Creek
were discovered. Mining began in 1915 and was substantially increased
the following year with the development of the deposits on Livengood
Creek and others on Gertrude, Ruth, Lillian, and Olive Creeks (Mertie,
1918, p. 256). The district continued to prosper and it was still productive
on a small scale in 1959. Total gold production through 1959 was 375,000
ounces, all from placers.
The bedrock in the Tolovana district
is distributed in several bands or belts that cross the area in a northeasterly
direction. The oldest rocks in the district crop out in the southeast;
the rocks become successively younger in a northwesterly direction.
Briefly, the bedrock units consist of the Tatalina Group, of Cambrian
or Precambrian age, Devonian and Silurian (?) sedimentary and igneous
rocks, a chert unit of Devonian or Carboniferous age, and Carboniferous
arenaceous and argillaceous units (Mertie, 1918, p. 230-256).
Igneous rocks, chiefly basic, occupy
a considerable area in the northwestern part of the district. Small
bodies of granitic intrusives are scattered throughout most of the district.
In the stream valleys, unconsolidated deposits of sand and gravel were
deposited during several stages in the Quaternary geomorphic cycle.
The earlier of these are only remnants and are seen as benches along
the valley walls (Mertie, 1918, p. 230-231).
Gold placers in the district are in
bench and stream deposits (Mertie, 1918, p. 259). The bench deposits
have been the more productive. The gold in the placers of Tolovana was
derived from low-grade lode deposits at the heads of many of the tributary
streams (Mertie, 1918, p. 274-275).