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SAMPLE INFO : 46AC260
Sample ID:46AC260
Station ID:46AC260
Latitude:51.86
Longitude:-176.638
Datum:NAD83
Date Sampled:1946-01-01
Sample Type 1:Lava
Sample Type 2:Dome
Field Lithology:Andesite
Text Description:
Andesite porphyry dome of Tertiary age. Zeto point basalt porphyry, from the Sand Hill Quarry, about half a mile north of the breakwater at the entrance to Sweeper Cove. Hornblende andesite porphyry. A medium light-gray (N7) porphyritic rock, about one-fourth phenocrysts. Phenocrysts are predominately plagioclase, ranging in size from 5 to 0.1 mm. The median composition of the plagioclase is about An55. Many of the phenocrysts show reverse zoning to a composition of about An73, succeeded by normal zoning to about An50. Hornblende is the commonest of the colored constituents; the prisms show outer rims of augite, which are due to reaction with the magma. The single large flake of biotite has a reaction rim of magnetite and is embedded in green hornblende. One round grain of quartz has the appearance of a xenocryst. The groundmass consists of plagioclase, averaging about An43, quartz, and orthoclase. Some calcite is in part interstitial to clear, unaltered plagioclase crystals of the groundmass, but has developed a reaction border of epidote against augite.

References:
Magmatic differentiation in Tertiary and Quaternary volcanic rocks from Adak and Kanaga Islands, Aleutian Islands, 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
46AC26051.86-176.638Unknown, Unknown1946-01-01 Adak Island. Sand Hill Quarry, about half a mile north of the breakwater at the entrance to Sweeper CoveAndesite porphyry dome of Tertiary age. Zeto point basalt porphyry, from the Sand Hill Quarry, about half a mile north of the breakwater at the entrance to Sweeper Cove. Hornblende andesite porphyry. A medium light-gray (N7) porphyritic rock, about one-fourth phenocrysts. Phenocrysts are predominately plagioclase, ranging in size from 5 to 0.1 mm. The median composition of the plagioclase is about An55. Many of the phenocrysts show reverse zoning to a composition of about An73, succeeded by normal zoning to about An50. Hornblende is the commonest of the colored constituents; the prisms show outer rims of augite, which are due to reaction with the magma. The single large flake of biotite has a reaction rim of magnetite and is embedded in green hornblende. One round grain of quartz has the appearance of a xenocryst. The groundmass consists of plagioclase, averaging about An43, quartz, and orthoclase. Some calcite is in part interstitial to clear, unaltered plagioclase crystals of the groundmass, but has developed a reaction border of epidote against augite.46AC260Whole Rock 59.16 0.4 16.87 6.14 0.16 2.54 7.37 3.54 1.18 0.36 99.881085NN3.932.57H2OP=0.88; H2OM=1.39NNB V=0, M=SPEC, R=1085;Be V=0, M=SPEC, R=1085;Ba V=0.03, M=SPEC, R=1085;Sr V=0.1, M=SPEC, R=1085;La V=0, M=SPEC, R=1085;Zr V=0.004, M=SPEC, R=1085;Pb V=0, M=SPEC, R=1085;Cu V=0.003, M=SPEC, R=1085;Ni V=0.0009, M=SPEC, R=1085;Co V=0.001, M=SPEC, R=1085;Cr V=0.001, M=SPEC, R=1085;V V=0.01, M=SPEC, R=1085;Ga V=0.0007, M=SPEC, R=1085;Mo V=0, M=SPEC, R=1085;Ag V=0, M=SPEC, R=1085;In V=0, M=SPEC, R=1085;Cd V=0, M=SPEC, R=1085;As V=0, M=SPEC, R=1085;Sb V=0, M=SPEC, R=1085;Sn V=0, M=SPEC, R=1085;Ge V=0, M=SPEC, R=1085;Tl V=0, M=SPEC, R=1085;

SAMPLE LOCATION

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