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SAMPLE INFO : 14
Sample ID:14
Station ID:14
Latitude:56.58
Longitude:-169.63
Datum:NAD83
Date Sampled:1948-01-01
Sample Type 1:Lava
Sample Type 2:Sill
Text Description:
Sample of an apophysis of limburgite from a layer of semicrystalline, porphyritic hyalobasanite about 3 feet thick. It may be a flow, but is likely a sill. In the apophyses the rock becomes very dense and black, but still remains slightly porphyritic. Thin sections reveal that it corresponds to limburgite containing olivine, augite, and magnetite, but practically no feldspar, as primary phases. Olivine is often distinctly zoned. Augite is reddish in color, shows hourglass structure and is highly zoned. Positive 2V is around 60 degrees with strong dispersion r>v; the directions of the extinctions are also highly dispersed, ??c=45 degrees. It is a titaniferous augite. Zeolites are seen in cavities.

References:
Geology and petrology of the Pribilof 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
1456.58-169.63Barth, T. F. W.1948-01-01 St. George volcanic fieldOn the seashore, 1 mile south of Garden Cove, St. George IslandSample of an apophysis of limburgite from a layer of semicrystalline, porphyritic hyalobasanite about 3 feet thick. It may be a flow, but is likely a sill. In the apophyses the rock becomes very dense and black, but still remains slightly porphyritic. Thin sections reveal that it corresponds to limburgite containing olivine, augite, and magnetite, but practically no feldspar, as primary phases. Olivine is often distinctly zoned. Augite is reddish in color, shows hourglass structure and is highly zoned. Positive 2V is around 60 degrees with strong dispersion r>v; the directions of the extinctions are also highly dispersed, ??c=45 degrees. It is a titaniferous augite. Zeolites are seen in cavities.14Whole Rock 40.4 3.25 13.16 12.44 0.2 11.26 10.34 3.4 0.8 0.86 100.4301NN5.347.62H2OM=2.24; H2OP=1.68NN

SAMPLE LOCATION

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