Dome Prospect, Iditarod Mining District, Bethel Census Area, Alaska, USAi

Regional Level Types
Dome Prospect	Prospect
Iditarod Mining District	Mining District
Bethel Census Area	Census Area
Alaska	State
USA	Country

Location: The Dome prospect is on hill 1234 which is souhwest of Dome Creek and northwest of Quartz Gulch; in the NW1/4 of section 19, T. 23 N., R. 48 W., of the Seward Meridian. Cobb (1972 [MF 363]; 1976 [OFR 76-576]).
Geology: The Dome prospect is on a large, generally untested, gold anomaly in soils at the northeast end of the Donlin Creek swarm of dikes and sills. Quartz-sulfide veins and veinlets cut granite porphyry and quartz-feldspar porphyry dikes and sills as well as hornfels derived from the Upper Cretaceous, Kuskokwim Group (Miller and Bundtzen, 1994; Szumigala, Dodd, and Arribas, 2000). The greater extent of hornfels here relative to its general absence near the Donlin Creek lode (ID167) suggests that a larger intrusion might underlie this area. Quartz-feldspar porphyry and igneous breccias were identified in drill core (McCoy and others, 1999). Gold appears to be associated with widespread arsenopyrite (McCoy and others, 1999). Chalcopyrite occurs sparsely. Samples by the U.S. Geological Survey and by the Alaska Division of Geological and Geophysical Surveys in the early 1980s contained up to 1.0 parts per million (ppm) silver, 5.1 ppm mercury, 70 ppm tin, 3.0 ppm bismuth, and 1,000 ppm arsenic in addition to gold (McGimsey and others, 1988). Szumigala, Dodd, and Arribas (2000) believe that the intrusive and sediment -hosted, gold and copper mineralization represent a porphyry-type deposit. They also report fluid inclusion temperatures of 400 degrees C which suggests a magmatic source for the hydrothermal fluids and further supports the idea of porphyry-type mineralization here.
Workings: The prospect was sampled by the U.S. Geological Survey and by the Alaska Division of Geological and Geophysical Surveys in the early 1980s (McGimsey and others, 1988). Westgold explored the Dome prospect from 1988 to 1990 but did not drill it (Retherford and McAtee, 1994). Placer Dome drilled the prospect in 1996 and 1997 but the total footage has not been released (McCoy and others, 1997).
Age: The mineralization is 65.0 Ma based on 40K/40Ar age date reported by Miller and Bundtzen (1994).
Alteration: Development of secondary biotite and sericite.

Commodities (Major) - Au, Cu; (Minor) - Ag, As, Bi, Hg, Sn
Development Status: None
Deposit Model: Porphyry gold-copper deposit; (Cox and Singer, 1986; model 20c); possibly the p

Other Databases

Link to USGS - Alaska:	ID169

Other Regions, Features and Areas containing this locality

References