Characteristic textures of volcanic rocks On Isle Royale. Isle Royale National Park, Keweenaw County, Michigan. 1971.
Dates
Date Taken
1971
Summary
Isle Royale National Park, Michigan. Characteristic textures of volcanic rocks On Isle Royale: pegmatite from the differentiated zone of the Greenstone Flow on the east end of Passage Island. This rock has a texture in which all of the minerals, especially the plagioclase, are larger when compared with those in most of the other rock types; the elongate plagioclase laths give the rock a matted appearance. Circa 1971. Figure 4-E, U.S. Geological Survey Professional paper 754-C; Figure 12-E, U.S. Geological Survey Bulletin 1309.
Summary
Isle Royale National Park, Michigan. Characteristic textures of volcanic rocks On Isle Royale: pegmatite from the differentiated zone of the Greenstone Flow on the east end of Passage Island. This rock has a texture in which all of the minerals, especially the plagioclase, are larger when compared with those in most of the other rock types; the elongate plagioclase laths give the rock a matted appearance. Circa 1971. Figure 4-E, U.S. Geological Survey Professional paper 754-C; Figure 12-E, U.S. Geological Survey Bulletin 1309.
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