Unnamed Occurrence (ARDF - NM005; on Martha Creek), Nome Mining District, Nome Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - NM005; on Martha Creek)	- not defined -
Nome Mining District	Mining District
Nome Census Area	Census Area
Alaska	State
USA	Country

Location: Occurrences of sulfidized rock were reported by Sainsbury, Smith, and Kachadoorian (1972) about 1.5 miles south of the confluence of Martha Creek with Tisuk River. The best occurrences were reported to be on the west side of Martha Creek. The occurrences are approximately located but probably within about a quarter of a mile of the coordinates.
Geology: Several oxidized (limonitic?) quartz-breccia zones, as much as 100 feet across, occur in this area, especially on the west side of Martha Creek (Sainsbury, Smith, and Kachadoorian, 1972). Anomalous amounts of bismuth, copper, and lead were reported. The area is underlain by amphibolite facies graphitic metasedimentary rocks that are locally gneissic in character. Sainsbury, Smith, and Kachadoorian (1972) mapped granite stocks and felsic dikes in the Martha Creek drainage and a small tourmalinized granite about three-quarters of a mile west of these occurrences. The tourmalinized granite is at the head of a creek that parallels Martha Creek and also flows north to Tisuk River. The amphibolite facies metasedimentary rocks are now considered to have a late Proterozoic or early Paleozoic protolith (Till and Dumoulin, 1994; Hannula and others, 1995), perhaps correlative with parts of the Nome Group. Like the Nome Group, these rocks probably underwent regional blueschist facies metamorphism in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Armstrong and others, 1986; Hannula and McWilliams, 1995). The blueschist facies rocks were recrystallized to greenschist facies or higher metamorphic grades in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson and Arth, 1983; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998).
Workings: No workings were reported; occurrences were found by Sainsbury and his coauthors Smith, and Kachadoorian (1972) during reconnaissance in 1970.
Age: Cretaceous, probably related to nearby or buried tourmalinized granites.
Alteration: Oxidation and silicification.

Commodities (Major) - Bi, Cu, Pb
Development Status: None
Deposit Model: Quartz breccia in amphibolite facies metasedimentary rocks.

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Link to USGS - Alaska:	NM005

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References