National Geochronological Database sample #858

Quarry, Monzonite

Geographic location
-114.991667, 39.261111
114° 59' 30" W, 39° 15' 40" N
White Pine county, NV
Ruth 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
SE1/4 SE1/4 SEC. 9, T16N, R62E, NE CORNER OF LIBERTY OPEN-PIT COPPER MINE NEAR RUTH , ROBINSON MINING DISTRICT
Source of sample Quarry
Rock name Monzonite
Description LIBERTY PIT STOCK. HIGHLY ALTERED MONZONITE PORPHYRY COMPOSED OF ALTERED ORTHOCLASE, QUARTZ, AND BIOTITE (LIGHT BROWN, CLUSTERED) PHENOCRYSTS IN A GROUNDMASS OF QUARTZ AND SERICITE.
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 SE1/4 SEC. 9, T16N, R62E, NE CORNER OF 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 -114.991667, 39.261111
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K-Ar age determinations

Age estimate 113.42 ± 3Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
80-100 MESH ANALYZED SEPARATE CONTAINED 2% IMPURITIES
Analytical details
Lab sample ID L-1013
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 8.9 %
Radiogenic 40Ar concentration 15
Radiogenic Ar 90 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)