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SAMPLE INFO : 7
Sample ID:7
Station ID:7
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
Low-sllica dacite of Little Sitkin dacite. Color: grayish black (N 2). Texture: hypocrystalline, porphyritic with plagioclase as much as 5 mm in length. Most plagioclase megaphenocryst and microphenocrysts, 25-30 percent, group around An56 but range from An25 to An78; complex oscillatory zoning common; many feldspars contain vermicular areas of dusty brown glass. Orthopyroxene, 8-10 percent, occurs as individual euhedrons and as cores in many clinopyroxene, 6 percent, crystals. Acceasory minerals: magnetite, 2 percent, and oxyhornblende, 1 percent (xenocrysts?) Fluidal glassy groundmass contains angular crystal fragments, 3 percent, and euhedral rods of pyroxene (?).

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
751.9531178.5356Snyder, G. L.Little SitkinLittle Sitkin dacite from coast half a mile north of Pratt Point. Specimen taken from within 6 inches of contact with rhyodacite of Pratt Point member.Low-sllica dacite of Little Sitkin dacite. Color: grayish black (N 2). Texture: hypocrystalline, porphyritic with plagioclase as much as 5 mm in length. Most plagioclase megaphenocryst and microphenocrysts, 25-30 percent, group around An56 but range from An25 to An78; complex oscillatory zoning common; many feldspars contain vermicular areas of dusty brown glass. Orthopyroxene, 8-10 percent, occurs as individual euhedrons and as cores in many clinopyroxene, 6 percent, crystals. Acceasory minerals: magnetite, 2 percent, and oxyhornblende, 1 percent (xenocrysts?) Fluidal glassy groundmass contains angular crystal fragments, 3 percent, and euhedral rods of pyroxene (?).7Whole Rock 59.42 0.72 16.91 6.79 0.15 3.26 7.28 3.5 1.31 0.15 99.94424NN2.984.09H2OM=0.05; H2OP=0.43; CO2=0.01NN 28.7 329 8.1 745XRFB V=0.002, M=SPEC, R=424;Ba V=0.05, M=SPEC, R=424;Sr V=0.08, M=SPEC, R=424;K V=1.09, M=NN, R=745;Yb V=0.0003, M=SPEC, R=424;Y V=0.002, M=SPEC, R=424;Zr V=0.008, M=SPEC, R=424;Ni V=0.0006, M=SPEC, R=424;Co V=0.002, M=SPEC, R=424;Cr V=0.002, M=SPEC, R=424;Cu V=0.008, M=SPEC, R=424;V V=0.02, M=SPEC, R=424;Ga V=0.001, M=SPEC, R=424;Sc V=0.002, M=SPEC, R=424;Mo V=0.0002, M=SPEC, R=424;

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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