Rainy Day Prospect, Gold Mountain, Cleveland Peninsula, Ketchikan Mining District, Prince of Wales-Hyder Census Area, Alaska, USAi
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Latitude & Longitude (WGS84):
55° 36' 54'' North , 131° 58' 4'' West
Latitude & Longitude (decimal):
Type:
KΓΆppen climate type:
Nearest Settlements:
Place | Population | Distance |
---|---|---|
Ketchikan | 8,197 (2017) | 36.5km |
Saxman | 417 (2017) | 40.5km |
Metlakatla | 1,405 (2017) | 59.5km |
Mindat Locality ID:
199589
Long-form identifier:
mindat:1:2:199589:6
GUID (UUID V4):
90ff97f8-e127-4d7a-aad7-73abd526aae8
Location: The Rainy Day prospect is at an elevation of about 200 feet, approximately 0.2 mile inland from the southwest shore of Helm Bay, and about 1.4 miles from the mouth of the bay. The site is in section 19, T. 72 S., R. 88 E., of the Copper River Meridian. It corresponds to loc. 251 in Maas and others (1995, fig. 46), and to loc. 31 in Elliott and others (1978). The location is accurate within 0.1 mile.
Geology: The country rocks at this site are flyschlike metasedimentary rocks that gradationally intertongue with andesitic and basaltic metatuff (Berg and others, 1988, p. 17-19). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time (Brew, 1996, p. 27). Their premetamorphic age is uncertain. Berg and others (1988, p. 17) state that they closely resemble Upper Jurassic to mid-Cretaceous marine flysch and volcanic rocks nearby on Gravina Island. At the prospect, the bedded rocks are intruded by a 600-1000-foot-thick dike of granite porphyry (Wright and Wright, 1908, p. 156) or granodiorite (Maas and others, 1995, fig. 46). The dike probably is Late Cretaceous or younger, assuming that it postdates the regional metamorphism. The deposit consists of a 3- to 3.5-foot-thick quartz fissure vein in granite porphyry (Brooks, 1902, p. 58; Wright and Wright, 1908, p. 156). The vein strikes northwest and has been traced in outcrop for 300-500 feet; it contains small amounts of pyrite, sphalerite, and galena, and minute particles of native gold. The prospect was developed in the early 1900s by an opencut and a 105-foot tunnel. Maas and others (1995, table 25) report the following average metal contents in their samples from the Rainy Day prospect: 6.28 ppm Au, 13.2 ppm Ag, 48 ppm Cu, 732 ppm Pb, and 14 ppm Zn. Fluid inclusion studies of quartz vein material from several of the Helm Bay lodes suggest that the veins formed at temperatures and pressures consistent with conditions during the Late Cretaceous greenschist-grade regional metamorphism (Maas and others, 1995, p. 184).
Workings: The prospect was developed in the early 1900s by an opencut and a 105-foot tunnel. Maas and others (1995, table 25) report the following average metal contents in their samples from the Rainy Day prospect: 6.28 ppm Au, 13.2 ppm Ag, 48 ppm Cu, 732 ppm Pb, and 14 ppm Zn.
Age: Late Cretaceous.
Commodities (Major) - Au; (Minor) - Pb, Zn
Development Status: None
Deposit Model: Low-sulfide gold-quartz veins (Cox and Singer, 1956; model 36a)
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
5 valid minerals.
Detailed Mineral List:
β Galena Formula: PbS |
β Gold Formula: Au |
β Pyrite Formula: FeS2 |
β Quartz Formula: SiO2 |
β Sphalerite Formula: ZnS |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
Group 1 - Elements | |||
---|---|---|---|
β | Gold | 1.AA.05 | Au |
Group 2 - Sulphides and Sulfosalts | |||
β | Sphalerite | 2.CB.05a | ZnS |
β | Galena | 2.CD.10 | PbS |
β | Pyrite | 2.EB.05a | FeS2 |
Group 4 - Oxides and Hydroxides | |||
β | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
O | Oxygen | |
---|---|---|
O | β Quartz | SiO2 |
Si | Silicon | |
Si | β Quartz | SiO2 |
S | Sulfur | |
S | β Galena | PbS |
S | β Pyrite | FeS2 |
S | β Sphalerite | ZnS |
Fe | Iron | |
Fe | β Pyrite | FeS2 |
Zn | Zinc | |
Zn | β Sphalerite | ZnS |
Au | Gold | |
Au | β Gold | Au |
Pb | Lead | |
Pb | β Galena | PbS |
Other Databases
Link to USGS - Alaska: | KC031 |
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