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SAMPLE INFO : 5
Sample ID:5
Station ID:5
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
Oxidized low-silica dacite of Little Sitkin dacite. Color: pale red (5R 5/2). Texture: porphyritic with plagioclase phenocrysts as much as 4 mm long. Plagioclase, 25-30 percent, ranges in separate and individually zoned crystals from An29(?) to An55 with an average composition of about An50; many of the larger feldspars form a graphic "intergrowth" with dusty glass; some have a rim of clear feldspar in optical continuity with the fritted cores; two-fluid inclusions and small needles (0.002 mm by 0.04 mm) of apatite(?) or pyroxene(?) occur in feldspar. Orthopyroxene, 6 percent, occasionally cores clinopyroxene, 9 percent, crystals. Accessory minerals: magnetite, 3 percent, and tridymite, 1 percent. Fluidal groundmass highly charged with hematite dust.

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
551.9531178.5356Snyder, G. L. Little SitkinLittle Sitkin dacite from thin boudinaged seam at contact of the rhyodacite in the Pratt Point member on coast half a mile north of Pratt PointOxidized low-silica dacite of Little Sitkin dacite. Color: pale red (5R 5/2). Texture: porphyritic with plagioclase phenocrysts as much as 4 mm long. Plagioclase, 25-30 percent, ranges in separate and individually zoned crystals from An29(?) to An55 with an average composition of about An50; many of the larger feldspars form a graphic "intergrowth" with dusty glass; some have a rim of clear feldspar in optical continuity with the fritted cores; two-fluid inclusions and small needles (0.002 mm by 0.04 mm) of apatite(?) or pyroxene(?) occur in feldspar. Orthopyroxene, 6 percent, occasionally cores clinopyroxene, 9 percent, crystals. Accessory minerals: magnetite, 3 percent, and tridymite, 1 percent. Fluidal groundmass highly charged with hematite dust.5Whole Rock 58.83 0.77 17.01 7.07 0.15 3.39 7.36 3.4 1.24 0.19 99.96424NN5.711.89H2OM=0.17; H2OP=0.37; CO2=0.01NN 27.8 321 7.6 745XRFK V=1.02, M=NN, R=745;

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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