ABSTRACT: Tectonic Development of Cretaceous/Cenozoic Sedimentary Basins of the East Coast Region, North Island, New Zealand.

CUTTEN, HUNTLY N. C., Department of Scientific and Industrial Research, Geology and Geophysics, Lower Hutt, New Zealand

The East Coast of the North Island, New Zealand, occupies an accretionary wedge on part of the Australian/Pacific plate boundary. Relative motion between the two plates is oblique transpressive. Petroleum exploration in the region is complicated by the extent and variation of structural deformation which reflects partitioning of the relative plate motion. Tectonism in the region has both influenced Cretaceous/Cenozoic basin development and deformed the basin sediments. Dextral strike slip faults occur within and flanking the axial ranges of Mesozoic greywacke basement, and extend the full length of the East Coast region. Movement on these faults may be in the order of 150-200 km since the early Miocene, and most of these faults are active to the present day. Convergent motion is appar nt from uplift of the axial ranges, beginning in the late Miocene, and from thrust-related folding across the forearc basin.

A region-wide compilation of Cretaceous/Cenozoic geology includes a structural interpretation of the region based on recent mapping and a series of transects from Raukumara Peninsula in the north to Marlborough in the south.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)