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SAMPLE INFO : Snyder_1959_7
Sample ID:Snyder_1959_7
Station ID:Snyder_1959_7
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: 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. Accessory 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
StationIDLatitudeLongitudeGeologistDateVisitedAge InfoVolcanoEruptionLocation DescriptionText DescriptionSample IDSample Type 1Sample Type 2Final UnitMaterialSiO2TiO2Al2O3FeOTMnOMgOCaONa2OK2OP2O5Total-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_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-silica 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. Accessory minerals: magnetite, 2 percent, and oxyhornblende, 1 percent (xenocrysts?) Fluidal glassy groundmass contains angular crystal fragments, 3 percent, and euhedral rods of pyroxene (?).Snyder_1959_7LavaWhole-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 units are percent 1.09745XRF: Rb, Sr, Ni; NN: K;
Snyder_1959_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-silica 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. Accessory minerals: magnetite, 2 percent, and oxyhornblende, 1 percent (xenocrysts?) Fluidal glassy groundmass contains angular crystal fragments, 3 percent, and euhedral rods of pyroxene (?).Snyder_1959_7LavaWhole-rock H2OM=0.05; H2OP=0.43; CO2=0.01NN units are percent 0.05units are percent 0.08 units are percent 0.0003 units are percent 0.002units are percent 0.008 units are percent 0.002 0.02units are percent 0.002 0.002units are percent 0.0006units are percent 0.008 units are percent 0.001units are percent 0.0002 424SPEC

SAMPLE LOCATION

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