Surface-water, ground-water, and sediment geochemistry of epizonal and shear-hosted mineral deposits in the Tintina Gold Province--arsenic and antimony distribution and mobility: Chapter G in Recent U.S. Geological Survey studies in the Tintina Gold Pr

Epigenetic mineral deposits in the Tintina Gold Province
are generally characterized by high concentrations of arsenic
and antimony in their mineral assemblage. A total of 347 samples (ground water, surface water, and stream sediment) were
collected to investigate the distribution and mobility of arsenic
and antimony in the environment near known mineral deposits. Samples were collected from east to west at Keno Hill and
Brewery Creek, Yukon, Canada; and Cleary Hill, True North,
Scrafford Mine, Fairbanks, Ryan Lode, Stampede Creek,
Slate Creek, and Donlin Creek, all in Alaska. Surface- and
ground-water samples are all slightly acidic to near-neutral
in pH (5-8), have a wide range in specific conductance
(surface water 17-2,980 microsiemens per centimeter and
ground water 170-2,940 microsiemens per centimeter), and
show elevated dissolved arsenic and antimony concentrations
(arsenic in surface water is less than 1 to 380 micrograms per
liter and in ground water is less than 1 micrograms per liter to
1.5 milligrams per liter; antimony in surface water is less than
2 to 660 micrograms per liter and in ground water is less than
2 to 60 micrograms per liter). Stream sediments downstream
from these deposits have high concentrations of arsenic and
antimony (arsenic median is 1,670 parts per million, maximum is 10,000 parts per million; antimony median is 192
parts per million, maximum is 7,200 parts per million). The
mobility of arsenic and antimony is controlled by the local
redox environment, with arsenic being less mobile in oxidized
surface waters relative to antimony, and arsenic more mobile
in reduced ground water. These factors suggest that both antimony and arsenic may be useful pathfinder elements in water
and sediment for targeting similar style deposits elsewhere in
the Tintina Gold Province.