National Geochronological Database sample #3641

Core or cutting, Granodiorite

Geographic location
-117.125, 40.541667
117° 7' 30" W, 40° 32' 30" N
Lander county, NV
Antler Peak 1:62,500 scale map quadrangle
Accurate to within 1 minute (~1 mile)
SW1/4 SEC. 22, T31N, R43E; COMPOSITE SAMPLE OF NINE DRILL CORE SPLITS FROM DEPTHS OF 74.7 TO 131.1 METERS BELOW GROUND SURFACE, COPPER CANYON AREA
Source of sample Core or cutting
Rock name Granodiorite
Description ALTERED GRANODIORITE OF COPPER CANYON AREA; COARSE- TO MEDIUM-GRAINED PORPHYRITIC ALTERED BIOTITE GRANODIORITE
Laboratories USGS Menlo Park
Compiler name Nichols, S.L.
Date compiled 1978 04
Precision of location Accurate to within 1 minute (~1 mile)
Location comment SW1/4 SEC. 22, T31N, R43E; COMPOSITE SAMPLE OF NINE DRILL CORE SPLITS FROM DEPTHS OF 74.7 TO 131.1 METERS BELOW GROUND SURFACE, COPPER CANYON AREA
Bibliographic reference Theodore, T.G., Silberman, M.L., and Blake, D.W., 1973, Geochemistry and Potassium-Argon Ages Of Plutonic Rocks In The Battle Mountain Mining District, Lander County, Nevada: U.S. Geological Survey Professional Paper 798A, A24pp.
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Geologic map unit -117.125, 40.541667
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K-Ar age determinations

Age estimate 39.14 ± 0.8Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
-40+80 MESH
Analytical details
Lab sample ID 10. (MB-23)
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 9.05 %
Radiogenic 40Ar concentration 5.155
Radiogenic Ar 82 %