National Geochronological Database sample #15425

Geographic location
-110.958333, 33.408333
110° 57' 30" W, 33° 24' 30" N
Gila county, AZ
Inspiration 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
PINTO VALLEY PIT, GLOBE-MIAMI DISTRICT
Rock name Quartz monzonite
Description LOST GULCH QUARTZ MONZONITE (MINERALIZED)--CONTAINS ABOUT 30% SECONDARY PHLOGOPITIC BIOTITE
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 PINTO VALLEY PIT, 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 -110.958333, 33.408333
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K-Ar age determinations

Age estimate 59.7 ± 0.7Ma
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
Analytical details
Lab sample ID 21
Decay constants 4.962E-04, 0.581E-04, 1.1167E-04
Radiogenic 40Ar concentration 7.6554
Radiogenic Ar 62 %
Comments PRECAMBRIAN AGE HAS BEEN RESET BY LATE CRETACEOUS-PALEOCENE THERMAL EVENTS. TIME OF MINERALIZATION