Pleistocene glaciation of New Zealand has been recognized since about 1860, but multiple glaciation has gained general acceptance only recently. The glacial history is directly linked with the marine succession at Ross, Westland, where strongly folded early Pleistocene till, varve silts, and gravels conformably succeed marine Pliocene beds and are overlain unconformably by practically undeformed late Pleistocene moraines. Pleistocene culmination of the Kaikoura orogeny resulted in a clear distinction between early and late Pleistocene glacial deposits and probably explains a mid-Pleistocene hiatus in the successions.

In the proposed chronology, early Pleistocene glacial deposits are referred to the Ross glacial stage. Tectonically undeformed deposits that have accumulated since the present topography has existed are referred to two glacial stages (Waimaungan and Otiran) of the late Pleistocene separated by a full interglacial stage. Local names are given to four distinct advances of substage value recognizable within the Otiran stage. Field recognition depends upon differences in ice extent, erosion and weathering of deposits, and differences of altitude due to progressive lowering of river profiles.

There is as yet little basis for overseas correlation. The Otiran stage may extend farther back into post-Sangamon time than Wisconsin in the strict sense; correlation of Waimaungan with Illinoian is reasonable, though speculative.

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