Saddle Prospect, Council Mining District, Nome Census Area, Alaska, USAi

Regional Level Types
Saddle Prospect	Prospect
Council Mining District	Mining District
Nome Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is 1.3 miles northeast of Bluff, 0.6 miles north of Norton Sound, and at 360 feet elevation on the saddle between Daniels Creek (SO006) and Swede Creek (SO005).
Geology: The Saddle prospect is known from the work of Ford (1993) and Ford and Snee (1996). A large gold and arsenic anomaly in soils led to its discovery. Gold-bearing quartz veins are localized in extensional joints that strike easterly and dip moderately to the south in quartz-muscovite schist. The host schist is similar to that at the nearby Bluff (SO135), Swede Creek (SO133) and Koyana Creek (SO136) lode prospects. This schist is a band intercalated in Paleozoic marble (Herried, 1965; Mulligan, 1971; Till and others, 1986). The veins are discontinuous and commonly less than 3 inches thick. Gold grades are irregularly distributed; vein intersections up to 3.3 feet across contain up to 1.8 ounces Au per ton. Minerals identified in the veins include arsenopyrite, biotite, carbonate, chlorite, fluorite, marcasite, plagioclase, pyrite, pyrrhotite, quartz, titanite, and white mica. Alteration minerals in the host schist include plagioclase, chlorite, carbonate, white mica, biotite, titanite, and tourmaline. The white mica in the veins is muscovite and that in the host schist is phengite. A sample of vein white mica gave a Ar/Ar plateau date of 109.1 +/- 0.2 Ma and metamorphic white mica in the host schist gave Ar/Ar total gas dates of 122.6 +/- 0.4 Ma and 122.4 +/- 0.2 Ma (Ford and Snee, 1996). This age is similar to that for some other lode gold deposits on southern Seward Peninsula. The southern Seward Peninsula lode gold deposits formed as a result of mid-Cretaceous metamorphism (Apodoca, 1994; Ford, 1993, Ford and Snee, 1996; Goldfarb and others, 1997) that accompanied regional extension (Miller and Hudson, 1991) and crustal melting (Hudson, 1994). This higher temperature metamorphism was superimposed on high pressure/low temperature metamorphic rocks of the region.
Workings: Surface soil sampling and some diamond drilling by BHP-Utah International was done here about 1990.
Age: Mid-Cretaceous, the age of some other lode gold deposits on southern Seward Peninsula. At this prospect, a sample of vein white mica gave a Ar/Ar plateau date of 109.1 +/- 0.2 Ma and metamorphic white mica in the host schist gave Ar/Ar total gas dates of 122.6 +/- 0.4 Ma and 122.4 +/- 0.2 Ma (Ford and Snee, 1996).
Alteration: Quartz veining; alteration minerals in the host schist include plagioclase, chlorite, carbonate, white mica, biotite, titanite, and tourmaline.

Commodities (Major) - Au
Development Status: None
Deposit Model: Gold-bearing quartz veins along extension joints in quartz-mica schist; low sul

Other Databases

Link to USGS - Alaska:	SO175

Other Regions, Features and Areas containing this locality

References