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SAMPLE INFO : Snyder_1959_11
Sample ID:Snyder_1959_11
Station ID:Snyder_1959_11
Latitude:51.9531
Longitude:178.5356
Datum:NAD83
Sample Type 1:Lava
Field Lithology:Dacite
 Text Description:
High-silica dacite of the Double Point dacite. Color: brownish gray (5 YR 5/l). Texture: hypocrystalline, porphyritic with feldspar phenocrysts as much as 3 mm long. Zoned and twinned plagioclase, 25-30 percent, varies in composition from An35 to An45 and averages An40. Accessory minerals are euhedral orthopyroxene, 2 percent; subhedral clinopyroxene, 2 percent; magnetite, 1 percent; and tridymite, 1 percent. The fluidal glassy to cryptocrystalline groundmass carries pyroxene, magnetite and plagioclase microlites. The plagioclase microlites have an average composition of An43.

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_1151.9531178.5356Snyder, G. L. Little SitkinDouble Point dacite located half a mile northeast of the summit of Little Sitkin volcanoHigh-silica dacite of the Double Point dacite. Color: brownish gray (5 YR 5/l). Texture: hypocrystalline, porphyritic with feldspar phenocrysts as much as 3 mm long. Zoned and twinned plagioclase, 25-30 percent, varies in composition from An35 to An45 and averages An40. Accessory minerals are euhedral orthopyroxene, 2 percent; subhedral clinopyroxene, 2 percent; magnetite, 1 percent; and tridymite, 1 percent. The fluidal glassy to cryptocrystalline groundmass carries pyroxene, magnetite and plagioclase microlites. The plagioclase microlites have an average composition of An43.Snyder_1959_11LavaWhole-rock 65.13 0.52 16.49 4.54 0.12 2.05 5.14 4.07 1.68 0.13 100.1424NN2.382.39H2OM=0.05; H2OP=0.08; CO2=0NN 32.6 320 8.9 units are percent 1.39745XRF: Rb, Sr, Ni; NN: K;

SAMPLE LOCATION

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Page modified: August 1, 2017 15:29
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