Photomicrograph of intrusion breccia, west of Boulder. Boulder County, Colorado. circa 1932.
Dates
Date Taken
1932
Summary
Album caption and index card: Photomicrograph of intrusion breccia of group 11 from Logan mine, 5 miles west of Boulder. Highly fragmented granite and some porphyry and early vein material lie in a biotite-flecked glassy groundmass that is partly silicified and sericitized. b, Fragment of biotite latite; g, glassy groundmass. Crossed nicols. Boulder County, Colorado. Notes: Published as figure XVII-A in U.S.Geological Survey. Professional Paper 223. 1950.
Summary
Album caption and index card: Photomicrograph of intrusion breccia of group 11 from Logan mine, 5 miles west of Boulder. Highly fragmented granite and some porphyry and early vein material lie in a biotite-flecked glassy groundmass that is partly silicified and sericitized. b, Fragment of biotite latite; g, glassy groundmass. Crossed nicols. Boulder County, Colorado.
Notes: Published as figure XVII-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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