Stratigraphy of the Castlecliffian type section: 10 mid‐Pleistocene sequences from the Wanganui coast, New Zealand

Abstract The 160 m thick Castlecliff coast section was deposited during the middle Pleistocene (c. 1.07–0.35 Ma) and comprises 10 disconformity‐bound cyclothems or sequences. A typical sequence has three parts: (1) a basal suite of shore face and inner shelf sediments with intertidal and shallow subtidal molluscan faunas, and cross‐bedded, pebbly shell gravels (type A shellbeds); (2) a mid‐cycle shellbed, which contains in situ offshore molluscs in a matrix of muddy fine sandstone or fine sandy siltstone (type B shellbeds); and (3) an upper unit of terrigenous siltstone, either bedded and barren of fossils, or bioturbated and with a sparsely scattered in situ fauna similar to that of the subjacent shellbed. The three parts of each sequence correspond respectively to the transgressive systems tract, mid‐cycle shellbed, and highstand systems tract of the sequence stratigraphic model. Sequence 7 (Kupe Formation, Upper Kai‐Iwi Shellbed, Upper Kai‐Iwi Siltstone) is designated as the type example of the Castlec...