| Synthesis of Petrographic, Geochemical, and Isotopic Data for the Boulder Batholith, Southwest Montana Contributor(s): U. S. Department of the Interior (Author) |
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ISBN: 1496099273 ISBN-13: 9781496099273 Publisher: Createspace Independent Publishing Platform OUR PRICE: $16.14 Product Type: Paperback Published: March 2014 |
| Additional Information |
| BISAC Categories: - Reference |
| Physical Information: 0.09" H x 8.5" W x 11" (0.28 lbs) 44 pages |
| Descriptions, Reviews, Etc. |
| Publisher Description: The Late Cretaceous Boulder batholith in southwest Montana consists of the Butte Granite and a group of associated smaller intrusions emplaced into Mesoproterozoic to Mesozoic sedimentary rocks and into the Late Cretaceous Elkhorn Mountains Volcanics. The Boulder batholith is dominated by the voluminous Butte Granite, which is surrounded by as many as a dozen individually named, peripheral intrusions. These granodiorite, monzogranite, and minor syenogranite intrusions contain varying abundances of plagioclase, alkali feldspar, quartz, biotite, hornblende, rare clinopyroxene, and opaque oxide minerals. Mafic, intermediate, and felsic subsets of the Boulder batholith intrusions are defined principally on the basis of color index. |