Apatite Fission-Track Analysis as a Paleotemperature Indicator for Hydrocarbon Exploration

Abstract

Apatite Fission-Track Analysis (AFTA) is emerging as an important new tool for thermal history analysis in sedimentary basins. At temperatures between approximately 20°C and 150°C over times of the order of 1 to 100 my, fission tracks in apatite are annealed. This is due to a rearrangement of the damage present in unetched tracks, with the result that less of a track is etchable than in fresh, newly created tracks. Because of this, the length of an etched fission track reduces with increasing annealing, and in turn, the track density (and hence the fission-track age) is also decreased. In selected boreholes in the Otway basin, southeastern Australia, apatites from the Otway Group show reduct..