The Makara faulted outlier and the age of Cook Strait

Abstract

Abstract The lithology and foraminiferal content of a faulted outlier of Pliocene conglomerate, sandstone, and mudstone at Makara in the south of the Wellington Peninsula are evidence of an important marine transgression during the Opoitian, The beds have the characteristics of deposits in a wide-mouthed embayment, with a basal shallow-water conglomerate and, in the upper part of the sequence, mudstone deposited probably deeper than 50 fathoms. As the rocks are 200 ft thick, the relative rise of sea level was more than 500 ft. The abundance of delicate thin-shelled Foraminifera, and the absence of Miliolidae and thick-shelled shallow-water forms, which are being transported widely throughout Cook Strait sediments by strong turbulent currents at the present day, indicate that a strait was not then in existence. The deposit does, however, provide evidence that makes possible a correlation of the lime and mode of development of Cook Strait with the Manawatu Gorge.