<p>This study examines the final emergence of the southeastern Wairarapa within a sequence stratigraphic framework. New exposures of the Pleistocene marginalmarine Hautotara Formation, and non-marine Te Muna Formation allow facies to be detailed and sequence architecture to be analysed. Cyclicity observed within the facies successions of the Hautotara and Te Muna formations are placed in a series of four motifs. These motifs record 40 kyr glacioeustatic cyclicity superimposed upon the basinward to landward progression of the environments, showing the region shallowing through time. The positions of the top of the Pukenui Limestone and the base of the Hautotara Formation are revised, and are now at the top of the “Pukenui C” - a widespread marker bed, which also removes a historical nomenclatural gap. The recognition of the significance of the coccolith Gephyrocapsa sinuosa within the underlying Pukenui Limestone allows this contact to be dated at 1.73 Ma. The ~1.6 Ma age limit provided by a number of tephra within the lower sediments of the Te Muna Formation allow the ages of the examined formations to be constrained further. The eight 40 ka cycles identified within the Hautotara Formation suggests deposition between 1.73 and 1.42 Ma. The Hautotara - Te Muna Formation is revealed to be diachronous, with the base of the Te Muna Formation type section shown to be much younger, 1.12 Ma, than the 1.58 Ma age of the lower contact observed elsewhere in the region. A series of palaeogeographic reconstructions at 1.73, 1.58 and 1.57 Ma demonstrate how closely related sedimentation patterns are to structural growth, with marginal-marine Hautotara Formation sedimentation persisting in the centre of the study area well after the initiation of Te Muna Formation terrestrial deposition to the north and south of this site.</p>
The Early Quaternary Marine to Terrestrial Transition of the Southeastern Wairarapa, New Zealand
