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SAMPLE INFO : Snyder_1959_12
Sample ID:Snyder_1959_12
Station ID:Snyder_1959_12
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
Text Description:
Rhyodacite of Pratt Point member of Little Sitkin dacite. Color: yellowish gray (5 P 7/1) to medium light gray (N 6). Texture: hypocrystalline, vesicular with "hairy" pumice developed locally, porphyritic with hornblende phenocrysts as much as 7 mm long and feldspar phenocrysts as much as 4 mm long. Plagioclase, 15-20 percent, ranges in composition from An27 to An50 and averages An40; sometimes poikilitic with inclusions of hornblende. Accessory minerals: oxyhornblende, 3-4 percent; hypersthene, 2-3 percent; quartz, 2-3 percent; magnetite, 1 percent. The quartz is characterized by conchoidal fractures and is very susceptible to plucking during grinding. The groundmass is about half small bubbles and half clear pinkish glass (N=1.490). The few plagioclase microlites average An39( ?).

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
Snyder_1959_1251.9531178.5356Snyder, G. L. Little SitkinPratt Point member of Little Sitkin dacite from central part of mapped area about 0.9 mile south of East PointRhyodacite of Pratt Point member of Little Sitkin dacite. Color: yellowish gray (5 P 7/1) to medium light gray (N 6). Texture: hypocrystalline, vesicular with "hairy" pumice developed locally, porphyritic with hornblende phenocrysts as much as 7 mm long and feldspar phenocrysts as much as 4 mm long. Plagioclase, 15-20 percent, ranges in composition from An27 to An50 and averages An40; sometimes poikilitic with inclusions of hornblende. Accessory minerals: oxyhornblende, 3-4 percent; hypersthene, 2-3 percent; quartz, 2-3 percent; magnetite, 1 percent. The quartz is characterized by conchoidal fractures and is very susceptible to plucking during grinding. The groundmass is about half small bubbles and half clear pinkish glass (N=1.490). The few plagioclase microlites average An39( ?).Snyder_1959_12Whole Rock 68.99 0.38 15 3.65 0.12 1.15 3.45 4.3 2.06 0.11 99.86424NN1.522.27H2OM=0.08; H2OP=0.64; CO2=0.01NN 45.1 245 5.9 745XRFK V=1.7, M=NN, R=745;

SAMPLE LOCATION

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