Radiogenic, nucleogenic and fissiogenic noble gas compositions in early Archaean magmatic zircons from Greenland

Abstract

We report a full suite of radiogenic, nucleogenic and fissiogenic noble gas compositions obtained by step-heating experiments from early Archaean Greenland zircons. We estimated activation energy (E_a) of diffusion and closure temperatures (T_c) for radiogenic ⁴He^∗ and fissiogenic ⁸⁶Kr^∗ and ¹³⁶Xe^∗ in zircons. These data demonstrate that the combined study of (U-Th)/He and (U-Th)/Kr-Xe can provide powerful geochronological information on cooling ages and crystallization ages from the same samples.