National Geochronological Database sample #500

Geographic location
-82, 36
82° ' " W, 36° ' " N
NC
Accurate to within 30 minutes (~30 miles)
BLUE RIDGE PARKWAY, OVERLOOK AT 237 MILE MARKER
Rock name Gneiss
Description CAROLINA GNEISS
Laboratories Lamont (Columbia University)
Compiler name Madden, C.T.
Date compiled 1975 03
Precision of location Accurate to within 30 minutes (~30 miles)
Location comment BLUE RIDGE PARKWAY, OVERLOOK AT 237 MILE MARKER
Bibliographic reference Carr, D.R., and Kulp, J.L., 1957, Potassium-argon method of geochronology: Geological Society of America Bulletin, v. 68, p. 763-784
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Geologic map unit -82, 36
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K-Ar age determinations

Age estimate 368 ± 18Ma
initial age disturbed by later metamorphism
Type of analysis conventional K-Ar
Rock or mineral analyzed whole rock
Analytical details
Lab sample ID (NOT GIVEN)
Decay constants 4.76E-04, 0.586E-04
K2O concentration 1.63 %