Advisor

Michael L. Cummings

Date of Award

1985

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Geology

Department

Geology

Physical Description

1 online resource (151 p.)

Subjects

Metamorphism (Geology) -- Washington (State) -- Wind River Region, Hydrothermal deposits -- Washington (State) -- Wind River Region, Geochemistry -- Washington (State) -- Wind River Region, Geology -- Washington (State) -- Wind River Region

DOI

10.15760/etd.5469

Abstract

The Wind River gold prospect is located in TSN, R7E of Skamania County, Washington, and is an epithermal gold-quartz vein system hosted in volcanic rocks of the Ohanapecosh Formation, a late Eocene to middle Oligocene unit of calcalkaline chemical composition. Andesitic pyroclastic rocks of the Ohanapecosh Formation are the host of mineralization in the study area, and form the lowest of several stratigraphic subunits. These pyroclastic rocks are overlain by two sequences of lava flows which cap the ridges and are folded by an anticlinal warp over the length of Paradise Ridge, plunging gently to the southeast. Toward the west, the number of flows decreases and the proportion of intercalated pyroclastic rocks increases. Numerous dikes cut the pyroclastic rocks at the Wind River prospect. Geochemical data show these dikes to have been feeders for the overlying lava flows. Differing degrees of alteration of the dikes relative to the most intensely altered pyroclastic rocks which they cut indicates a complex history of overlapping hydrothermal and volcanic activity at the prospect.

Description

If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to pdxscholar@pdx.edu and include clear identification of the work, preferably with URL

Persistent Identifier

http://archives.pdx.edu/ds/psu/20367

mcgowanplate1.jpg (7988 kB)
Plate I

mcgowanplate2.jpg (9810 kB)
Plate II

mcgowanplate3.jpg (9891 kB)
Plate III

Share

COinS