OXYGEN ISOTOPE COMPOSITION OF THE BONE PHOSPHATE OF AUSTRALIAN KANGAROOS - POTENTIAL AS A PALEOENVIRONMENTAL RECORDER

δ18O determinations of bone phosphate (δ18Op) have been performed on a suite of modern kangaroos and wallabies (known collectively as Macropods) that come from a wide variety of climatic zones within Australia. Macropod δ18Op values range from 16 to over 30%. (V-SMOW) and are found to correlate with environmental relative humidities. As Macropods are herbivorous mammals with low drinking water requirements that consume large amounts of plant leaf water, it is likely that the δ18Op signature of Macropods is reflecting leaf water fractionation processes that are controlled by relative humidity. These results indicate that δ18Op from fossil bones of Macropods and similar drought-tolerant herbivorous mammals may yield palaeohumidity estimates. © 1990.