COOL CRETACEOUS CLIMATES - NEW DATA FROM THE ALBIAN OF WESTERN-AUSTRALIA

Although previous geological, palaeobotanical and geochemical data fro m the Albian of Australia have suggested the possibility of cool palae oclimates, there are few well-constrained stable isotope palaeotempera tures studies from this region. In this paper we present the results o f stable isotope analyses of dimitobelid belemnites from the Albian Ge arle Siltstone, Carnarvon Basin, Western Australia. Oxygen isotope val ues for diagenetically least-altered samples give values ranging betwe en delta(18)O - 0.02 and 0.85 parts per thousand PDB, which equate to a mean palaeotemperature of 10.08 degrees C (assuming delta(w), of - 1 .2 parts per thousand SMOW). This value is broadly consistent with rec ently published isotope data from the Albian Antarctic and with estima tes for mid-Cretaceous latitudinal temperature gradients, implying tha t cool palaeoclimates occurred during a period of 'Greenhouse' Earth.