A pleistocene anticline at gladstone,wairarapa

Abstract

Middle Pleistocene strata near Gladstone comprise a lower,partly marine and partly non-marine, Gladstone Formation of Nukumaruan age, and an upper, ntirely non-marine, Ruamahanga Formation of late Pleistocene age.Both formations are strongly arched; the maximum dip of the Gladstone Formation is 24° and the dip of the Ruamahanga Formation decreases from 20° at the base to 7° at the top An angular unconformity separates the two formations; two angular unconformities separate three members within the Ruamahanga Formation, and a fourth angular unconformity separates all these beds from aggradational gravel of the Last Glaciation.Decrease in dip of younger strata indicates that the anticline was developing during the Pleistocene.Each of the three members of the Ruamahanga Formation is considered to have been deposited rapidly, and the durations of each of the unconformities are computed as 100,000 to 200,000 years