National Geochronological Database sample #853

Outcrop or artificial surface exposure, Monzonite

Geographic location
-114.991667, 39.255556
114° 59' 30" W, 39° 15' 20" N
White Pine county, NV
Ruth 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
SE1/4 NE1/4 SEC. 16, T16N, R62E, LIBERTY PIT NEAR RUTH, ROBINSON MINING DISTRICT
Source of sample Outcrop or artificial surface exposure
Rock name Monzonite
Description FINE-GRAINED PORPHYRITIC MONZONITE, CUTTING LIBERTY PIT STOCK, COMPOSED OF PLAGIOCLASE, ORTHOCLASE (STRONG SERICITIZATION), HORNBLENDE (INCIPIENT ALTERATION) PHENOCRYSTS IN A GROUNDMASS OF ORTHOCLASE, PLAGIOCLASE, QUARTZ (?), AND HORNBLENDE.
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 SE1/4 NE1/4 SEC. 16, T16N, R62E, 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 -114.991667, 39.255556
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K-Ar age determinations

Age estimate 105.12 ± 3Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed hornblende
ANALYZED SEPARATE CONTAINED 2% FELDSPAR
Analytical details
Lab sample ID L-958
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 1.54 %
Radiogenic 40Ar concentration 2.4
Radiogenic Ar 87 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)