GRAVITY SURVEY OF LOWER AWATERE DISTRICT MARLBOROUGH, NEW ZEALAND

Bouguer and residual gravity anomaly maps of the Lower Awatere District are presented. The gravity measurements support the concept that dip-slip faulting during the upper Tertiary was followed by transcurrent faulting in the Quaternary. A structural contour map of the top of the Torlesse Group basement derived from the residual gravity anomalies shows that the upper Tertiary rocks in the Lower Awatere Valley lie in a shallow basin centred about 3 miles east of Seddon. Positive residual anomalies over Torlesse Group greywackes are interpreted as resulting from basic igneous intrusions at depths less than 2 miles. © Taylor & Francis Group, LLC.