Apatite Fission Track Analysis (AFTA ®) and organic maturity data, including Vitrinite Reflectance (VR) and VRF™ methods have been applied to samples from the Cape Sorell-I well, offshore Western Tasmania, to provide a thermal history framework for understanding the burial and source rock maturation histories at this location. In addition, the AFTA results have important implications for the thermal and structural histories of the sediment provenance areas that provided detritus to the Cape Sorell Basin during the L. Cretaceous and E. Tertiary. AFTA and VR are used to identify, characterise and quantify any episodes of elevated paleotemperatures which have affected the well section, with particular emphasis on determining the timing of major paleo-thermal episodes, the magnitude of paleotemperatures in each episode, and the way in which paleotemperatures vary with depth. This information is used to infer the origins of the various episodes of heating and cooling, and provides rigorous constraints for modelling of the structural and source rock maturation histories.