A gravity survey of the Lower Awatere district, Marlborough, New Zealand

Abstract

The Lower Awatere District is situated in north-east Marlborough and covers an area of about 600 square miles (Map 1: 2). The coastal areas have mainly low and subdued relief, but rise inland to steep mountain ranges of over 5,000 ft. The area is remarkable for its diversity of topography which appears to have been controlled by the geological structure of the country (King, 1934: 33) Continued tectonic activity since the Miocene has resulted in complex structural geology in which reconnaisance geophysical work such as attempted here can assist the geologist. The variation of gravity in the area has been measured and examined in order to map the subsurface structure of the upper Cretaceous and Tertiary sedimentary rocks, to determine the position and nature of the faults, and to act as a general check on the geology. The area examined was too large to map geologically as well as geophysically in the time available, and since the geology was already mapped in reasonable detail, the geology has been taken from published sources.