National Geochronological Database sample #4593

Outcrop or artificial surface exposure, Diabase

Geographic location
-73.966667, 40.85
73° 58' " W, 40° 51' " N
Bergen county, NJ
Central Park 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
Source of sample Outcrop or artificial surface exposure
Rock name Diabase
Laboratories Yale
Compiler name Godoy, M.M.
Date compiled 1978 07
Precision of location Accurate to within 1 minute (~1 mile)
Bibliographic reference Armstrong, R.L., and Besancon, J., 1970, A Triassic Time Scale Dilemma: K-Ar Dating Of Upper Triassic Mafic Igneous Rocks, Eastern U.S.A. and Canada and Post-Upper Triassic Plutons, Western Idaho, U.S.A.: Eclogae Geologicae Helvetiae, v. 63, p. 15-28.
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Geologic map unit -73.966667, 40.85
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K-Ar age determinations

Age estimate 196.66 ± 2Ma
age of intrusion
Type of analysis conventional K-Ar
6.82%, 6.81%, 6.72%, 6.86% K; 54.5XE-6, 54.9XE-6, 55.4XE-6 STP CC RAD AR-40
Rock or mineral analyzed biotite
Analytical details
Lab sample ID 16
Decay constants 4.72E-04, 0.584E-04, 1.19E-04*
K2O concentration 8.19 %
Radiogenic 40Ar concentration 24.5
Radiogenic Ar 928195 %