A Reconnaissance gravity survey and geological interpretation of the northern half of the South Island of New Zealand

Abstract

Early in 1952, the writer approached Dr. E. I. Robertson, Director of the Geophysics Division, D.S.I.R., and asked for suggestions for a Thesis subject in Geology, involving Geophysical methods. Dr. Robertson suggested the gravity survey of the Northern half of the South Island, the work to form part of the survey of the whole of New Zealand. Professor C. A. Cotton kindly permitted the writer to accept this subject, even though it contains a large amount of physics. The Geophysics Division required a network of accurate base stations (a "skeleton"), to be used as starting points for future work in the area. The writer was left to choose geological problems which could be investigated during the setting up of the skeleton stations. Messrs. H. E. Fyfe and H. W. Wellman of the Geological Survey kindly assisted, by suggesting suitable problems. It was estimated that about six months field work would be involved, and as it was not convenient for the writer to spend as long as that in the field, Mr. J. Lawrie of the Magnetic Survey, Christchurch, was asked to set up most of the skeleton stations, in accordance with the writer's instructions. Mr. J. Lawrie made 357 separate measurements at 148 stations spread over nearly the whole area of the Survey. On the 22nd April, 1953, the writer took over the field work, and completed the skeleton and observed most of the stations needed for geological purposes.