Marine Gravity and Magnetic Studies of the Solomon Islands

  1. Leon Knopoff,
  2. Charles L. Drake and
  3. Pembroke J. Hart
  1. J. C. Rose,
  2. George P. Woollard and
  3. Alexander Malahoff

Published Online: 18 MAR 2013

DOI: 10.1029/GM012p0379

The Crust and Upper Mantle of the Pacific Area

The Crust and Upper Mantle of the Pacific Area

How to Cite

Rose, J. C., Woollard, G. P. and Malahoff, A. (2013) Marine Gravity and Magnetic Studies of the Solomon Islands, in The Crust and Upper Mantle of the Pacific Area (eds L. Knopoff, C. L. Drake and P. J. Hart), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM012p0379

Author Information

  1. Hawaii Institute of Geophysics, University of Hawaii, Honolulu, Hawaii

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 20 APR 2012

Book Series:

  1. Geophysical Monograph Series

Book Series Editors:

  1. Waldo E. Smith

ISBN Information

Print ISBN: 9780875900124

Online ISBN: 9781118663738

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Keywords:

  • Amplitudes;
  • Bathymetry;
  • Gravity anomaly charts;
  • Magnetic anomalies;
  • Marine gravity and magnetic studies;
  • Residual gravity anomaly;
  • Solomon Islands

Summary

From October through December of 1965, marine gravity and magnetic studies of the Solomon Islands region were carried out aboard HMS Dampier, the British hydrographic survey vessel. With the La Coste and Romberg sea gravimeter S9 and a Varian Associates proton-precession magnetometer, approximately fourteen thousand miles of gravimetric and magnetic measurements were collected under unusually favorable weather conditions. A free-air anomaly contour chart and a Bouguer anomaly contour chart were then constructed for the region from the gravity data obtained on Dampier, data obtained on USS Wandank in 1964, data obtained by Scripps Institution of Oceanography on RV Argo in 1960, and the data obtained on HMS Telemechus in 1956, USS Bergall in 1949, and USS Capitaine in 1948. A total force magnetic anomaly chart was drawn from the data obtained aboard HMS Dampier. Bathymetric readings taken concurrently, together with additional data from the Scripps Institution of Oceanography Lusiad and Proa expeditions, were used to draw a preliminary bathymetric chart of the region. The gravity anomalies in the region southeast of New Britain and between Bougainville and New Guinea appear to be excessively positive by more than 100 mgal. Amplitudes of magnetic anomalies are generally less than 200 γ and in the form of elongate bipoles striking perpendicular to the observed structural trends. Depth estimations suggest a three-layer crust, and computed susceptibility contrasts suggest that the magnetic anomalies are associated with intrusive basalts or andesites.