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SAMPLE INFO : 11
Sample ID:11
Station ID:11
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
High-silica dacite of the Double Point dacite. Color: brownish gray (5 YR 5/l). Texture: hypocrystalline, porphyritic with feldspar phenocrysts as much as 3 mm long. Zoned and twinned plagioclase, 25-30 percent, varies in composition from An35 to An45 and averages An40. Accessory minerals are euhedral orthopyroxene, 2 percent; snbhedral clinopyroxene, 2 percent; magnetite, 1 percent; and tridymite, 1 percent. The fluidal glassy to cryptocrystalline groundmass carries pyroxene, magnetite and plagioclase microlites. The plagioclase microlites have an average composition of An43.

References:
Geology of Little Sitkin Island, Alaska

GEOCHEM DATA
StationIDLatitudeLongitudeGeologistDateVisitedVolcanoEruptionLocation DescriptionText DescriptionSample IDMaterialSiO2TiO2Al2O3FeOTMnOMgOCaONa2OK2OP2O5Total-majorsREF majorsMETH majorsFe2O3/Fe203T origFeO/FeOT origVolatiles csvMETH volatilesCsRbBaSrLaCePrNdSmEuGdTbDyHoErTmYbLuYZrNbHfTaPbThUScVCrFeCoNiCuZnGaMoAsNaKRef trace1METH trace1RbBaSrLaCeNdSmEuGdDyErYbLuYZrNbPbThUScTiVCrNiCuZnGaRef trace2METH trace2Light csvHalogen csvother major csvother lile csvother ree csvother hfse csvother hpe csvother tm csvother misc csv
1151.9531178.5356Snyder, G. L.Little SitkinDouble Point dacite located half a mile northeast of the summit of Little Sitkin volcanoHigh-silica dacite of the Double Point dacite. Color: brownish gray (5 YR 5/l). Texture: hypocrystalline, porphyritic with feldspar phenocrysts as much as 3 mm long. Zoned and twinned plagioclase, 25-30 percent, varies in composition from An35 to An45 and averages An40. Accessory minerals are euhedral orthopyroxene, 2 percent; snbhedral clinopyroxene, 2 percent; magnetite, 1 percent; and tridymite, 1 percent. The fluidal glassy to cryptocrystalline groundmass carries pyroxene, magnetite and plagioclase microlites. The plagioclase microlites have an average composition of An43.11Whole Rock 65.13 0.52 16.49 4.54 0.12 2.05 5.14 4.07 1.68 0.13 100.1424NN2.382.39H2OM=0.05; H2OP=0.08; CO2=0NN 32.6 320 8.9 745XRFK V=1.39, M=NN, R=745;

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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