USGS Professional Paper 1697 - Alaska Resources Library

Metallogenic Belts Formed During Proterozoic
Sedimentation, Rifting, and Hydrothermal
Activity Along Cratons or Craton Margins
Sinuk River Metallogenic Belt of Massive
Sulfide-Barite and Stratabound Fe and Mn
Deposits (Belt SR), Northwestern Alaska
The Sinuk River metallogenic belt of stratiform massive
sulfide-barite and stratabound Fe deposits occurs in
the Sinuk River area in the southwestern part of the Seward
Peninsula in northwestern Alaska (fig. 3; tables 3, 4) (Nokleberg
and others, 1997b, 1998). The metallogenic belt occurs
in a 250 km 2
region of metamorphosed, upper Paleozoic,
carbonate-dominated rocks of the Seward metamorphosed
continental margin terrane (Nokleberg and others, 1994c,
1997c), about 30 km west of Nome (Herreid, 1968; Hudson
and others, 1977; Bundtzen and others, 1994, 1995; New-
55
50
60
65
0 200 400 m
60
75 80
65
80
30
85
Proterozoic Metallogenic Belts (2500 to 570 Ma; figures 2, 3) 17
berry and others, 1997). At least 15 separate occurrences
of massive to disseminated galena, sphalerite, fluorite, and
barite, and massive hematite occur in the area. The deposits
vary widely in morphology and size and consist of (1) disseminated
to massive barite sulfide lenses (Aurora Creek,
Nelson, Rocky Mountain Creek, Quarry), which are hosted
in felsic metavolcanic schist, carbonate rock, and metamorphosed
mafic flows(?), and which are interpreted as kuroko
massive sulfide and replacement deposits, and (2) massive,
stratabound segregations of hematite, magnetite, and pyrolusite,
interpreted as volcanogenic(?) Fe and Mn deposits
(American, Bear, Cub, Monarch) that are hosted in calcschist
and marble.
Aurora Creek Massive Sulfide-Barite Deposit
The Aurora Creek massive sulfide-barite deposit (Herreid,
1968, 1970; Bundtzen and others, 1994, 1995; Schmidt,
1997b) consists of disseminated to massive sphalerite,
galena,barite, pyrite, magnetite, and minor chalcopyrite in
a b
a b
65
30
a - Quartz-rich sandstone
b - Conglomerate lenses
in sandstone
Sericite-chlorite schist
Marl
Migmatite
Amphibolite
Schist
Gabbro and diorite (Late Proterozoic)
Ore bodies: a - known;
b - indicated by geophysical data
Mineralized host rock
Fault
Contact
Strike and dip of schistosity
Strike and dip of sedimentary
rock bedding
Sedimentary and
metamorphic rock
(Late Proterozoic -
Riphean)
Archean
crystalline
rock
Figure 6. Verkhny-Omolon ironstone deposit, Omolon metallogenic belt, Russian Northeast. Schematic geologic map. Adapted from
Gelman and Fadeev (1983). See figure 2 and table 4 for location.