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SAMPLE INFO : 87-WAD-9
Sample ID:87-WAD-9
Station ID:87-WAD-9
Latitude:62.1537
Longitude:-144.3688
Datum:NAD83
Date Sampled:1987-00-00
Sample Type 1:Lava
Sample Type 2:Flow
Field Lithology:Dacite
Text Description:
Nathlie Mountain hornblende dacite flow (Pleistocene). Medium- to dark-gray, columnar-jointed, massive dacite flow that is moderately to highly porphyritic. Flow contains phenocrysts of rounded plagioclase (5-15%, as large as 5 mm), altered hornblende (1-3%, as long as 2 mm), and hypersthene (trace to 1%, <1 mm), in trachytic to pilotaxitic groundmass of plagioclase microlites and cryptocrystalline material. Mineralogically and chemically similar to hornblende dacite intrusion (Qnd), which suggests that intrusion may have breached surface toward end of Nathlie Mountain volcanic activity. * * * Thickness variable, locally greater than 300 m.

References:
Geologic map of the Gulkana A-1 Quadrangle, south-central 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
87-WAD-962.1537-144.3688Duffield, W. A.1987-00-00 Nathlie Mountain rocks within Gulkana A-1 quadrangle. Latitude and longitude derived from paper map.Nathlie Mountain hornblende dacite flow (Pleistocene). Medium- to dark-gray, columnar-jointed, massive dacite flow that is moderately to highly porphyritic. Flow contains phenocrysts of rounded plagioclase (5-15%, as large as 5 mm), altered hornblende (1-3%, as long as 2 mm), and hypersthene (trace to 1%, <1 mm), in trachytic to pilotaxitic groundmass of plagioclase microlites and cryptocrystalline material. Mineralogically and chemically similar to hornblende dacite intrusion (Qnd), which suggests that intrusion may have breached surface toward end of Nathlie Mountain volcanic activity. * * * Thickness variable, locally greater than 300 m.87-WAD-9LavaWhole-rock 63.6 0.57 16.5 4.17 0.08 2.56 5.34 3.84 1.75 0.17 100.152262NN1.72.67H2OP=0.59; H2OM=0.04; CO2=0.02RAPIDA

SAMPLE LOCATION

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