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Geochemistry and petrogenesis of the Laramie anorthosite complex, Wyoming

LITHOS

By:
, , and
DOI: 10.1016/0024-4937(81)90049-9

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Abstract

A geochemical investigation of the Laramie anorthosite complex determined that monsonite associated with the complex are characterized by positive Eu anomalies and display a regular variation in composition with distance from the monzonite/county rock contact. Anorthositic rocks have major and trace element abundance typical of similar complexes. The internal variations in the monzonite were produced by in situ fractionation and contamination. The data indicate that anorthosite and monzonite cannot be comagmatic. It is proposed that the anorthosite and monzonite of the complex evolved from two distinct magmas, and that two stages of anatectic melting contributed to the evolution of the monzonite. An initial stage of partial melting was induced by intrusion of a gabbroic anorthosite magma into the lower crust; a second partial melting event occurred after emplacement where heat from the intrusions melted country rocks resulting in extensive contamination ofthe monzonite. ?? 1981.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Geochemistry and petrogenesis of the Laramie anorthosite complex, Wyoming
Series title:
LITHOS
DOI:
10.1016/0024-4937(81)90049-9
Volume
14
Issue:
2
Year Published:
1981
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
LITHOS
First page:
113
Last page:
132