Early Earth

Abstract

By U–Pb, Rb–Sr, and K–Ar methods, an age interval from 5.0 to 2.8 Gawas estimated for the oldest rocks in the Earth in the late 1950s. Model ages of 5.3–4.5 Ga were calculated from abundances of ⁴⁰K (Starik 1961) and at ca. 4.6 Ga from mean concentrations of ⁴⁰K in crust and ⁴⁰Ar in atmosphere (Brandt 1965; Schwartzman 1973). The latter age was substantiated using more precise dating of meteorites by U–Pb, Lu–Hf, Re–Os, and other methods. Meteorites were unequivocally specified as the oldest subjects of the Solar system (e.g. Shukolyukov and Begemann 1996).