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SAMPLE INFO : 10
Sample ID:10
Station ID:10
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
High-silica dacite of Double Point dacite. Color: medium dark gray (N 4). Texture: hypocrystalline, porphyritic with blocky feldspar phenocrysts with maximnm diameter of 5 mm. Eleven sections of the plagioclase, 25-30 percent, perpendicular to both albite twinning and basal cleavage give anorthite contents that appear to be distributed evenly from An23 to A55; complex zones and intergrowths common; groundmass microlites may group around An17 but cannot be determined accurately; two-fluid inclusions from 0.004-0.02 mm in diameter occupy negative crystals in certain zones of the feldspar. Stubby euhedral hypersthene, 5-10 percent, is pleochroic in light pink and light green. Accessories are clinopyroxene, 1 percent; magnetite, 2 percent; oxyhornblende, 1 percent; and tridymite, 1 percent. Fluidal groundmass glass has N=1.504(?).

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
1051.9531178.5356Snyder, G. L.Little SitkinFrom small inlier of Double Point dacite about 1 mile west-northwestward of summit of Little Sitkin volcanoHigh-silica dacite of Double Point dacite. Color: medium dark gray (N 4). Texture: hypocrystalline, porphyritic with blocky feldspar phenocrysts with maximnm diameter of 5 mm. Eleven sections of the plagioclase, 25-30 percent, perpendicular to both albite twinning and basal cleavage give anorthite contents that appear to be distributed evenly from An23 to A55; complex zones and intergrowths common; groundmass microlites may group around An17 but cannot be determined accurately; two-fluid inclusions from 0.004-0.02 mm in diameter occupy negative crystals in certain zones of the feldspar. Stubby euhedral hypersthene, 5-10 percent, is pleochroic in light pink and light green. Accessories are clinopyroxene, 1 percent; magnetite, 2 percent; oxyhornblende, 1 percent; and tridymite, 1 percent. Fluidal groundmass glass has N=1.504(?).10Whole Rock 64.91 0.53 16.29 4.73 0.13 1.98 5.08 4.14 1.71 0.15 99.91424NN1.723.17H2OM=0.03; H2OP=0.31; CO2=0NN 33.8 296 6.1 745XRFK V=1.42, M=NN, R=745;

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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