Standard isotope dilution techniques were used for the argon determinations; the potassium determinations were done by flame photometry using a lithium internal standard.
Summary
Standard isotope dilution techniques were used for the argon determinations; the potassium determinations were done by flame photometry using a lithium internal standard.
The coordinates are represented in North American Datum of 1927 (NAD27). Location was derived from the following method(s): Location provided in GSA Bulletin, v. 86, no. 6, p. 819-829