White Cliff

Prospect, Undetermined

Commodities and mineralogy

Main commodities Au

Geographic location

Quadrangle map, 1:250,000-scale KC
Quadrangle map, 1:63,360-scale B-5
Latitude 55.351
Longitude -131.666
Nearby scientific data Find additional scientific data near this location
Location and accuracy The White Cliff prospect is at an elevation of about 300 feet, on a hillside overlooking the city of Ketchikan, and about 1.25 miles northwest of the mouth of Ketchikan Creek. The site is in section 24, T. 75 S., R. 90 E., of the Copper River Meridian. It corresponds to loc. 61 in Elliott and others (1978), and to loc. 275 in Maas and others (1995). The location is probably accurate within 0.2 mile.

Geologic setting

Geologic description

This part of Revillagigedo Island is underlain mainly by marine, pelitic sedimentary rocks and subordinate andesitic or basaltic volcanic rocks that are intruded by Cretaceous stocks, sills, and dikes of feldspar-porphyritic granodiorite, and by a stock and probably related plugs of Tertiary gabbro (Berg and others, 1988). The strata were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. They subsequently were contact metamorphosed to hornblende hornfels: locally, near some of the Cretaceous granodiorite contacts, and, more widely, peripheral to the Tertiary gabbro. The premetamorphic age range of the strata is uncertain. Berg and others (1988) note that they closely resemble Upper Jurassic to mid-Cretaceous flysch and volcanic rocks nearby on Gravina Island. The country rocks are cut by a high-angle fault along Tongass Narrows that displays about 4 miles of right-lateral offset.
According to U.S. Bureau of Mines claim records (1977), this prospect, which appears to be in hornfelsed strata near the contact of Tertiary gabbro stock, was staked for gold. Maas and others (1995, p. 201) report a 12-foot-long adit, dating from the early 1900s, at the site, but no mineralization. No other information about the prospect has been made public.
Geologic map unit (-131.667685611515, 55.350653135729)
Age of mineralization If there is a mineral deposit at this site, it probably is Cretaceous or younger in age.

Production and reserves

Workings or exploration Prospect was explored in early 1900s by a twelve-foot adit.
Indication of production None

References