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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 maximum 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
StationIDLatitudeLongitudeGeologistDateVisitedAge InfoVolcanoEruptionLocation 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 maximum 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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