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SAMPLE INFO : 6
Sample ID:6
Station ID:6
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
Low-silica dacite of Little Sitkin dacite. Color: medium gray (N 5). Texture: hypocrystalline, massive. Plagioclase, 20 to 25 percent, ranges in composition from An55 to An72; a few have fritted centers. Orthopyroxene, 2-3 percent, and clinopyroxene, 2-3 percent, both distinctly pleochroic in light pink and light green; a few orthopyroxene and clinopyroxene centers in differently oriented clinopyroxene crystals. One relict olivine grain, with a thick reaction rim of pyroxene and magnetite. No oxyhornblende xenocrysts although this mineral is plentiful in nearby thin laminae of rhyodacite. Groundmass brownish glass filled with magnetite dust and crystallites.

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
651.9531178.5356Snyder, G. L.Little SitkinLittle Sitkin dacite from interfingered contact zone on north side of rhyodacite of Pratt Point member about 0.9 mile south of East PointLow-silica dacite of Little Sitkin dacite. Color: medium gray (N 5). Texture: hypocrystalline, massive. Plagioclase, 20 to 25 percent, ranges in composition from An55 to An72; a few have fritted centers. Orthopyroxene, 2-3 percent, and clinopyroxene, 2-3 percent, both distinctly pleochroic in light pink and light green; a few orthopyroxene and clinopyroxene centers in differently oriented clinopyroxene crystals. One relict olivine grain, with a thick reaction rim of pyroxene and magnetite. No oxyhornblende xenocrysts although this mineral is plentiful in nearby thin laminae of rhyodacite. Groundmass brownish glass filled with magnetite dust and crystallites.6Whole Rock 58.92 0.75 17.12 6.8 0.15 3.21 7.19 3.39 1.34 0.15 99.81424NN2.64.5H2OM=0.23; H2OP=0.71; CO2=0.01NN 26.8 318 7.4 745XRFK V=1.1, M=NN, R=745;

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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