Lithostratigraphy of Pliocene strata, Central and Southern Hawke's Bay, New Zealand

Abstract

Te Aute Formation is here elevated to Te Aute Group and defined as all marine strata, in Central and Southern Hawke's Bay, that unconformably overlie Miocene and older rocks and, at most places, unconformably underlie Pleistocene strata. The group is characterised by shallow marine siliciclastic mudstone and sandstone, calcareous sandstone, and bioclastic limestone. The strata crop out discontinuously in a structurally complex region characterised by active compressional tectonics, with a northeast-southwest structural grain.

Te Aute Group is subdivided into six formations which are, in order of decreasing age: Mangatoro Formation, Kairakau Limestone, Mokopeka Sandstone, Awapapa Limestone, Raukawa Mudstone (Argyll Sandstone Member), and Te Onepu Limestone. It is characterised by rapid vertical and lateral facies changes reflecting tectonic deformation and glacio-eustatic sea-level fluctuations during deposition.

Keywords:

• Pliocene
• lithostratigraphy
• shallow marine strata
• Central and Southern Hawke's Bay
• Te Aute Group
• Mangatoro Formation; Kairakau Limestone
• Mokopeka Sandstone
• Awapapa Limestone
• Raukawa Mudstone
• Te Onepu Limestone
• new stratigraphic names