National Geochronological Database sample #3643

Core or cutting, Granodiorite

Geographic location
-117.133333, 40.541667
117° 8' " W, 40° 32' 30" N
Lander county, NV
Antler Peak 1:62,500 scale map quadrangle
Accurate to within 1 minute (~1 mile)
SE1/4 SEC. 21, T31N, R43E; COMPOSITE SAMPLE OF 9 DRILL-CORE SPLITS FROM DEPTHS OF 115.8 TO 123.4 METERS BELOW GROUND SURFACE, COPPER CANYON AREA
Source of sample Core or cutting
Rock name Granodiorite
Description ALTERED GRANODIORITE SILL; INTENSELY SERICITIZED AND PYRITIZED PORPHYRITIC GRANODIORITE WITH ""FRESH"" BIOTITE AND CHLORITE VEINLETS.
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 SE1/4 SEC. 21, T31N, R43E; COMPOSITE SAMPLE OF 9 DRILL-CORE SPLITS FROM DEPTHS OF 115.8 TO 123.4 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 -117.133333, 40.541667
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K-Ar age determinations

Age estimate 38.54 ± 0.8Ma
minimum age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
2% CHLORITE; -42+65 MESH SAMPLE
Analytical details
Lab sample ID 11. (MB-40)
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 9 %
Radiogenic 40Ar concentration 5.048
Radiogenic Ar 78 %
Comments MAY BE AGE OF MINERALIZATION