National Geochronological Database sample #852

Core or cutting, Rhyolite

Geographic location
-114.995833, 39.261111
114° 59' 45" W, 39° 15' 40" N
White Pine county, NV
Ruth 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
SW1/4 SE1/4 SEC. 9, T16N, R62E, DRILL CORE FROM N SIDE OF LIBERTY PIT NEAR RUTH , ROBINSON MINING DISTRICT
Source of sample Core or cutting
Rock name Rhyolite
Description FINE-GRAINED, PORPHYRITIC RHYOLITE INTRUSIVE COMPOSED OF QUARTZ, BIOTITE, AND PLAGIOCLASE (SERICITE ALONG CRACKS) PHENOCRYSTS IN A GROUNDMASS OF QUARTZ, ORTHOCLASE, AND BIOTITE.
Laboratories Lamont (Columbia University)
Compiler name Marvin, R.F.
Date compiled 1975 10
Precision of location Accurate to within 1 minute (~1 mile)
Location comment SW1/4 SE1/4 SEC. 9, T16N, R62E, DRILL CORE FROM N SIDE OF LIBERTY PIT NEAR RUTH , ROBINSON MINING DISTRICT
Bibliographic reference Mcdowell, F.W., 1971, K-Ar Ages Of Igneous Rocks From The Western United States: Isochron/West, No. 2, p. 1-16.
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Geologic map unit -114.995833, 39.261111
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K-Ar age determinations

Age estimate 37.81 ± 1.1Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
80-100 MESH SEPARATE OF 100% BIOTITE
Analytical details
Lab sample ID L-969
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 8.89 %
Radiogenic 40Ar concentration 4.89
Radiogenic Ar 86 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)