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SAMPLE INFO : 87-ARh-30
Sample ID:87-ARh-30
Station ID:87-ARh-30
Latitude:62.1426
Longitude:-144.0438
Datum:NAD83
Date Sampled:1987-00-00
Sample Type 1:Lava
Sample Type 2:Flow
Field Lithology:Dacite
Sample Unit:Qsd
Text Description:
Mount Sanford Dacite flows (Pleistocene). Massive, light- to medium-light-gray, conspicuously porphyritic dacite flows on west and southeast flanks of Mount Sanford. Flow on west flank contains phenocrysts of plagioclase (4-6%, 1-2 mm), hornblende (2-3%, 1 mm; mostly altered to opaque minerals), and opaque minerals (trace), in trachytic to cryptocrystalline groundmass. Flow fills pronounced topographic low that is possibly along postulated caldera wall; maximum thickness about 500 m. Flow on southeast flank is coarsely porphyritic, containing phenocrysts of plagioclase (15-20%, as large as 1 cm), clinopyroxene (1-3%, 1-2 mm), opaque minerals (1%), and biotite (trace), in microfelty groundmass that consists chiefly of feldspar. Maximum thickness about 150 m.

References:
Geologic map of the Gulkana A-1 Quadrangle, south-central 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
87-ARh-3062.1426-144.0438Richter, D. H.1987-00-00 SanfordMount Sanford rocks within Gulkana A-1 quadrangle. Latitude and longitude derived from paper map.Mount Sanford Dacite flows (Pleistocene). Massive, light- to medium-light-gray, conspicuously porphyritic dacite flows on west and southeast flanks of Mount Sanford. Flow on west flank contains phenocrysts of plagioclase (4-6%, 1-2 mm), hornblende (2-3%, 1 mm; mostly altered to opaque minerals), and opaque minerals (trace), in trachytic to cryptocrystalline groundmass. Flow fills pronounced topographic low that is possibly along postulated caldera wall; maximum thickness about 500 m. Flow on southeast flank is coarsely porphyritic, containing phenocrysts of plagioclase (15-20%, as large as 1 cm), clinopyroxene (1-3%, 1-2 mm), opaque minerals (1%), and biotite (trace), in microfelty groundmass that consists chiefly of feldspar. Maximum thickness about 150 m.87-ARh-30Whole Rock 66.4 0.66 16.2 3.88 0.12 1.08 2.99 5.38 2.9 0.24 99.432262NN2.621.49H2OP=0.04; H2OM=0.1; CO2=0.01RAPIDA

SAMPLE LOCATION

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