Charnockite

Title

Charnockite

Identifier

AD-22

Description

This particular charnockite has been described, with analyses by deWaard and Romey, "Petrogenetic Relationships in the Anorthosite-Charnockite Series of the Snowy Mountain Dome," in Anorthosite Volume, New York State Museum Memoir 18, p.307-315. In this article, the authors show that a gradational contact exists between the anorthosite and surrounding charnockitic rocks. This is interpreted as the result of a comagmatic history for the rocks in question. The charnockites contain occasional xenocrysts of andesine which are believed to have been plucked off of the already solidified anorthosite by the still molten charnockite. Hills and Isachsen (1975) have dated these rocks at 1173±14 Ma.
Thin section shows K-feldspar, quartz and clinopyroxene.

Date

1980

Contributor

Western Minerals Inc.

Spatial Coverage

Adirondack Highlands-collected from road cuts on NY Route 30 approximately 1 mile south of Beaver Creek or 6 miles south of Indian Lake.

Temporal Coverage

Precambrian

Accrual Method

Purchased from Western Minerals Inc.

Unit

Snowy Mountain Dome

Number of Thin Sections

1

Geolocation