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Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana

Professional Paper 1657

By:
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Abstract

Cretaceous intrusions hosted by the Proterozoic Newland Formation. The northern intrusion, centered on Boulder Baldy, consists of outer, intermediate, and core zones composed of aegirine-augite quartz monzonite, hornblende quartz monzodiorite, and biotite granodiorite, respectively. The southern intrusion, north of Mount Edith, is compositionally indistinguishable from the intermediate zone of the northern intrusion.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana
Series title:
Professional Paper
Series number:
1657
Edition:
-
Year Published:
2002
Language:
ENGLISH
Description:
30 p.