Pyroxene-quartz-plagioclase gneiss

Title

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

Western Minerals Inc.

Spatial Coverage

Adirondack Highlands-collected from a large road cut on the east side of NY routes 10 &29A across from the Canada Lake Store.

Temporal Coverage

Precambrian

Accrual Method

Purchased from Western Minerals Inc.

Unit

Royal Mountain Member, Green Lake Formation

Number of Thin Sections

1

Geolocation