National Geochronological Database sample #14180

Outcrop or artificial surface exposure, Quartz monzonite

Geographic location
-171.533333, 63.45
171° 32' " W, 63° 27' " N
AK
St. Lawrence 1:250,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
WESTERN PART OF ST. LAWRENCE ISLAND
Source of sample Outcrop or artificial surface exposure
Rock name Quartz monzonite
Description QUARTZ MONZONITE PLUTON
Laboratories USGS Menlo Park
Compiler name Degourville, A.E.
Date compiled 1984 04
Precision of location Accurate to within 1 minute (~1 mile)
Location comment WESTERN PART OF ST. LAWRENCE ISLAND
Bibliographic reference Patton, W.W., Jr., and Csejtey, B., Jr., 1980, Geologic Map Of St. Lawrence Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-1203.
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Geologic map unit -171.533333, 63.45
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K-Ar age determinations

Age estimate 93.5 ± 3Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
Analytical details
Lab sample ID 69APA219E
Decay constants 4.962E-04, 0.581E-04, 1.1167E-04
Radiogenic 40Ar concentration 11.02
Radiogenic Ar 87 %