Table 2. ⁴⁰Ar/³⁹Ar analytical data obtained on the plagiocases 83R77-82 and 85R18-23.

Notes: The ages are calculated using the decay constants recommended by Steiger and Jäger (1977). Correction factors for interfering isotopes produced by neutron irradiation in the McMaster reactor are (³⁶Ar/³⁷Ar)_Ca = 2.54 × 10^-4, (³⁹Ar/³⁷Ar)_Ca = 6.51 × 10^-4, and (⁴⁰Ar/³⁹Ar)_K = 2.87 × 10^-2; atm = atmospheric, ⁴⁰Ar* = radiogenic ⁴⁰Ar. Ca and K are produced by Ca-neutron and K-neutron interferences, respectively.