Photomicrograph of porphyritic granodiorite. Boulder County, Colorado. circa 1932.
Dates
Date Taken
1932
Summary
Album caption and index card: Photomicrograph of porphyritic granodiorite typical of rocks of group 4 from stock half a mile south of Jamestown. The primary alinement of feldspars responsible for the platy structure of the intrusive is clearly shown. i, Ilmenite; h, hornblende; p, plagioclase (andesine); q, quartz; t, titanite. Crossed nicols. Boulder County, Colorado. Notes: Published as figure XIII-A, in U.S.Geological Survey. Professional Paper 223. 1950.
Summary
Album caption and index card: Photomicrograph of porphyritic granodiorite typical of rocks of group 4 from stock half a mile south of Jamestown. The primary alinement of feldspars responsible for the platy structure of the intrusive is clearly shown. i, Ilmenite; h, hornblende; p, plagioclase (andesine); q, quartz; t, titanite. Crossed nicols. Boulder County, Colorado.
Notes: Published as figure XIII-A, in U.S.Geological Survey. Professional Paper 223. 1950.
Available in the U.S. Geological Survey Denver Library Photographic Collection, Lovering, T.S.
Rights
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