Pyroxene-quartz-plagioclase gneiss

Identifier

AD-3

Description

This specimen consists of 50-60% andesine, 20-30% quartz, and minor pyroxene and hornblende. Associated with this lithology are 2-6 inch layers of pyroxene-plagioclase granulite and amphibolite. It is believed that the Royal Mountain Member gneiss represents a metamorphosed layered instrusion of overall tonalitic composition. Numerous internal features, such as xenoliths and possible slump structures, support this hypothesis.
Thin section shows plagioclase, quartz and hornblende.

Date

1980

Contributor

Temporal Coverage

Accrual Method

Purchased from Western Minerals Inc.

Number of Thin Sections

1

Geolocation