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Sample info : 53-B-38
Sample ID:53-B-38
Station ID:53-B-38
Latitude:53.88707
Longitude:-166.93202
Datum:NAD83
Date Sampled:1953-01-01
Sample Type 1:Lava
Field Lithology:Basalt
Text Description:
Slightly altered feldspathic basalt porphyry. It is greenish gray to grayish green and contains phenocrysts 1 to 2 millimeters long. Phenocrysts compose 15 percent of the rock : 12 percent sodic labradorite, which forms embayed crystals, euhedral laths, and irregular grains and which contains normal and oscillatory zones and zones of dusty inclusions ; 3 percent angite or diopside, which form euhedral to anhedral crystals and crystal clusters and which alter to chlorite and uralite(?) pseudomorphs ; and a trace of olivine (?) , which appears as chlorite and uralite(?) pseudornorphs. The groundmass has a felty to granular texture and consists of plagioclase, altered pyroxene(?), and a black opaque mineral. Alteration is moderate ; chlorite and uralite (?) replace pyroxene
and olivine (?) .

References:
Geology of Unalaska Island and adjacent insular shelf, Aleutian Islands, Alaska


Sample Location

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Page modified: August 7, 2013 07:43
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