Sedimentology and stratigraphy of oyster concentrations in the Pliocene of Wanganui Basin (New Zealand)

MACMILLAN, L.; NELSON, C.; CASADIO, SILVIO; ROMERO, M. V.; BREZINA, S.

General Roca

Congreso; 11 Congreso de la Asociación Paleontológica Argentina; 2016

Asociación Paleontologica Argentina

Oyster shells can equally act as archives of paleoenvironmental information (e.g., salinity,temperature) and shellbeds are useful indicator in sequence stratigraphy. The PlioceneWilkies Shellbed in the Wanganui Basin (North Island, New Zealand) comprises oysteraccumulations up to 15 m thick involving the extinct oyster Crassostrea ingens Zittel, 1864.Individuals are up to 30 cm long, 7 cm thick and weigh as much as 2 kg. The shellbedconsists of a lower onlap shellbed (transgressive lag) and an overlying backlap shellbed(biostrome). The widespread shell δ18O (-3.0 to 3.0?) and δ13C (-2.6 to 1.8?) isotopicvalues support a range of marginal marine to marine