National Geochronological Database sample #856

Quarry, Monzonite

Geographic location
-114.994444, 39.261111
114° 59' 40" 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, LIBERTY OPEN-PIT COPPER MINE NEAR RUTH, ROBINSON MINING DISTRICT
Source of sample Quarry
Rock name Monzonite
Description LIBERTY PIT STOCK. PORPHYRITIC MONZONITE COMPOSED OF PLAGIOCLASE AND HORNBLENDE (PLAGIOCLASE AND SPHENE INCLUSIONS) PHENOCRYSTS IN A GROUNDMASS OF ORTHOCLASE, PLAGIOCLASE, AND QUARTZ.
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, LIBERTY OPEN-PIT COPPER MINE 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 -114.994444, 39.261111
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K-Ar age determinations

Age estimate 109.35 ± 4Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed hornblende
60-100 MESH ANALYZED SEPARATE CONTAINED 5% IMPURITIES
Analytical details
Lab sample ID L-960
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 1.22 %
Radiogenic 40Ar concentration 1.98
Radiogenic Ar 38 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)