National Geochronological Database sample #15455

Outcrop or artificial surface exposure, Granodiorite

Geographic location
-110.949167, 33.401111
110° 56' 57" W, 33° 24' 4" N
Gila county, AZ
Inspiration 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
GLOBE-MIAMI DISTRICT
Source of sample Outcrop or artificial surface exposure
Rock name Granodiorite
Description WILLOW SPRING GRANODIORITE
Laboratories USGS Menlo Park
Compiler name Marvin, R.F.
Date compiled 1984 11
Precision of location Accurate to within 1 minute (~1 mile)
Location comment GLOBE-MIAMI DISTRICT
Bibliographic reference Creasey, S.C., 1980, Chronology Of Intrusion and Deposition Of Porphyry Copper Ores, Globe-Miami District, Arizona: Economic Geology, v. 75, p. 830-844.
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Geologic map unit -110.949167, 33.401111
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K-Ar age determinations

Age estimate 71.3 ± 3Ma
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
Analytical details
Lab sample ID 52
Decay constants 4.962E-04, 0.581E-04, 1.1167E-04
Radiogenic 40Ar concentration 9.5098
Radiogenic Ar 18 %
Comments RESET AGE; PLUTON IS AROUND 1600 M.Y. OLD