FLUORINE RELATIVE DATING AND TAPHONOMY OF MOA BONE FROM PYRAMID VALLEY, NEW ZEALAND

The Pyramid Valley deposit in North Canterbury, South Island, New Zealand, contained the largest known assemblage of associated skeletons of moa (Aves: Dinornithiformes), an extinct group of giant ratite birds. Remains of four species of moa, as well as the remains of nearly 50 species of neornithine birds, as well as bats, lizards, and tuatara were collected during excavations from the late 1930s to the mid-1960s. Little, however, has been published on the faunal remains, and for the most part the collections have lain untouched in Canterbury Museum. Very few 14C ages have been obtained on faunal remains, although these include some of the earliest faunal radiocarbon ages measured anywhere in the world.Recently-obtained AMS radiocarbon ages confirm that the deposit was still forming just over 1000 years b.p., just before human settlement of New Zealand. Studies of the Pyramid Valley fauna resumed in the mid-1990s and have steadily increased, prompted by the revolution in ancient DNA and stable isotopic analyses of New Zealand Quaternary faunal materials. There is now increased interest in the biology of the giant birds themselves, partly to understand their extinction at the hands of human predators and anthropogenic environment change, and also as part of an ecologic analysis of past environments on which to base present management plans for endangered species and systems.

Recent advances in fluorine relative dating by ion chromatography have provided insights into the understanding of the mechanism of entrapment and deposition of moa remains that are fundamental to research on the living ecosystem represented by the deposit, and will provide a foundation for a solid chronology of deposition. Initial results indicate no correlation between the age of the bones and their spatial position within the site, nor between species distribution within the oldest subgroup. Thus, the distribution of entrapped moa species within the swamp appears to have been random and invariant with time.