National Geochronological Database sample #3914

Outcrop or artificial surface exposure, Vein

Geographic location
-117.161111, 37.7
117° 9' 40" W, 37° 42' " N
Nye county, NV
Goldfield 1:62,500 scale map quadrangle
Accurate to within 1 minute (~1 mile)
Source of sample Outcrop or artificial surface exposure
Rock name Vein
Description FINE-GRAINED ALUNITE VEINLET CUTTING ARGILLIZED MILLTOWN ANDESITE
Laboratories USGS Menlo Park
Compiler name Nichols, S.L.
Date compiled 1978 04
Precision of location Accurate to within 1 minute (~1 mile)
Bibliographic reference Ashley, R.P., and Silberman, M.L., 1976, Direct Dating Of Mineralization At Goldfield, Nevada, By Potassium-Argon and Fission-Track Methods: Economic Geology, v. 71, p. 904-924.
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Geologic map unit -117.161111, 37.7
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K-Ar age determinations

Age estimate 9.45 ± 1.7Ma
Type of analysis conventional K-Ar
2.23%, 2.25%, 2.25% K2O
Rock or mineral analyzed natroalunite
Analytical details
Lab sample ID I3-43
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 2.24 %
Radiogenic 40Ar concentration 0.3057
Radiogenic Ar 8 %
Comments AGE OF MINERALIZATION
Age estimate 6.13 ± 3.9Ma
Type of analysis conventional K-Ar
2.23%, 2.25%, 2.25% K2O; ARGON EXTRACTION SYSTEM NOT BAKED-OUT OVERNIGHT
Rock or mineral analyzed natroalunite
Analytical details
Lab sample ID I3-43
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 2.24 %
Radiogenic 40Ar concentration 0.198
Radiogenic Ar 23 %
Comments SPURIOUS AGE; TOO YOUNG