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SAMPLE INFO : 23MW3-1
Sample ID:23MW3-1
Station ID:23MW3-1
Latitude:56.58
Longitude:-169.63
Datum:NAD83
Sample Type 1:Lava
Text Description:
St. George Island, Group 1 type rocks (from Chang and others, 2009): "Group 1 rocks are commonly crystal poor (5-15 vol. % phenocrysts) and vesicular, with fine-grained, holocrystalline groundmasses. Phenocrysts are primarily olivine, although some rocks have clinopyroxene or opaque phenocrysts as well. The olivine phenocrysts are commonly equant or skeletal and vary widely in size and form from sample to sample and within rocks. Olivine compositions for seven rocks range from Fo90 to Fo61 and average Fo83. Clinopyroxene phenocrysts are generally small and euhedral and have average core and rim compositions of XMg=70 and 62, respectively. Clinopyroxene phenocrysts vary in color from tan to pink in plane-polarized light and often exhibit sector-zoning and occur in X- or star-shaped glomerocrystic clusters. The groundmasses generally consist of olivine, euhedral clinopyroxene, euhedral plagioclase laths, and opaque minerals. Modal nepheline was found in one rock (SG06-8). Abundant groundmass clinopyroxene is especially notable in group 1 rocks. The average clinopyroxene in the groundmass has a composition of XMg=66. Plagioclase compositions measured in two group 1 rocks are variable. The average plagioclase composition in sample SG05-28 is Ab36Or3An61, with two analyzed crystals having anomalous rims with an average composition of Ab48Or37An15. Plagioclase analyzed in sample SG05-31 is albite (Ab84Or12An3)."

References:
Petrogenesis of basaltic volcanic rocks from the Pribilof Islands, Alaska, by melting of metasomatically enriched depleted lithosphere, crystallization differentiation, and magma mixing

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
23MW3-156.58-169.63Unknown, Unknown St. George volcanic fieldGroup 1St. George Island, Group 1 type rocks (from Chang and others, 2009): "Group 1 rocks are commonly crystal poor (5-15 vol. % phenocrysts) and vesicular, with fine-grained, holocrystalline groundmasses. Phenocrysts are primarily olivine, although some rocks have clinopyroxene or opaque phenocrysts as well. The olivine phenocrysts are commonly equant or skeletal and vary widely in size and form from sample to sample and within rocks. Olivine compositions for seven rocks range from Fo90 to Fo61 and average Fo83. Clinopyroxene phenocrysts are generally small and euhedral and have average core and rim compositions of XMg=70 and 62, respectively. Clinopyroxene phenocrysts vary in color from tan to pink in plane-polarized light and often exhibit sector-zoning and occur in X- or star-shaped glomerocrystic clusters. The groundmasses generally consist of olivine, euhedral clinopyroxene, euhedral plagioclase laths, and opaque minerals. Modal nepheline was found in one rock (SG06-8). Abundant groundmass clinopyroxene is especially notable in group 1 rocks. The average clinopyroxene in the groundmass has a composition of XMg=66. Plagioclase compositions measured in two group 1 rocks are variable. The average plagioclase composition in sample SG05-28 is Ab36Or3An61, with two analyzed crystals having anomalous rims with an average composition of Ab48Or37An15. Plagioclase analyzed in sample SG05-31 is albite (Ab84Or12An3)."23MW3-1Whole Rock 43.66 2.862 13.9 12.987 0.206 10.05 10.57 4.1 1 0.857 98.8374882XRF12.987 23 352 794 35 88 29 270 69.5 0 5 19 248 205 175 105 4882XRF

SAMPLE LOCATION

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Page modified: July 14, 2014 13:37
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