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Table 2 Ar isotope analyses of representative aliquots of alunite

From: Improvement of 40Ar/39Ar age determinations for Quaternary basaltic rocks by eliminating the peak suppression effect

Sample IDPrevious protocolModified protocol
427-10427-11 619-12
fAmp± 1 sd% sdfAmp± 1 sd% sdfAmp± 1 sd% sd
40Ar104.75951.32741.27111.12201.59481.44209.56910.11250.05
39Ar1.79860.295116.412.92160.294210.074.87410.07061.45
38Ar0.09520.1101115.680.17880.107159.890.08690.065875.76
37Ar0.04810.0763158.680.03040.0756249.11− 0.07050.0565− 80.1
36Ar0.25410.00903.550.24230.00923.780.22320.00271.22
Moles (40Ar)3.48E-153.69E-156.96E-15
%40Ar*28.335.668.5
Ca/K0.2090.081− 0.083
Age (Ma)8.607.0715.21
± 1 sd1.300.730.23
% sd15.1210.321.48