Hautotara Formation, Mangaopari Basin, New Zealand: Record of a cyclothemic Pliocene‐Pleistocene marine to nonmarine transition

Abstract

The late Pliocene ‐ early Pleistocene Hautotara Formation in southeastern Wairarapa, New Zealand, comprises cyclic estuarine and shallow‐marine deposits. The formation conformably overlies the fully marine Pukenui Limestone and is overlain by the fluvio‐lacustrine Te Muna Formation. Hautotara Formation is a record of a tectonically induced regression from marine to nonmarine conditions. Within the Hautotara Formation, at least five glacio‐eustatically controlled cycles are superimposed on this tectonic record. The dual tectonic and glacio‐eustatic controls are modified by paleogeographic and hydrodynamic processes, producing a variety of lithofacies. The basal glacio‐eustatic cycle possibly represents a preserved lowstand estuary. A reinterpretation of the type section suggests that the top is a faulted repeat of the base of the Hautotara Formation. A new composite standard reference section is described for the Hautotara Formation. © 1995 The Royal Society of New Zealand.