Land Gravity Survey of the Solomon and Bismarck Islands

  1. Leon Knopoff,
  2. Charles L. Drake and
  3. Pembroke J. Hart
  1. T. S. Laudon

Published Online: 18 MAR 2013

DOI: 10.1029/GM012p0279

The Crust and Upper Mantle of the Pacific Area

The Crust and Upper Mantle of the Pacific Area

How to Cite

Laudon, T. S. (2013) Land Gravity Survey of the Solomon and Bismarck 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/GM012p0279

Author Information

  1. Wiscansin State University, Oshkosh, Wisconsin

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:

  • Bougainville;
  • Bouguer anomaly maps;
  • British Solomon Islands Protectorate (BSIP);
  • Gravity anomaly maps;
  • Land gravity survey;
  • Rabaul area;
  • Solomon and Bismarck Islands

Summary

Bouguer isogal maps of the Solomon and Bismarck Islands are characterized by large, extremely steep positive anomalies. Local anomalies can be related to near-surface geological features. Basement rocks and Quaternary volcanic centers are expressed as gravity highs; Upper Tertiary sedimentary basins are expressed as gravity lows. The regional gravity field of the Solomons consists of a broad low, elongated parallel to the trend of the islands, with smaller highs, corresponding to individual islands, superimposed on its flanks. The gravity results suggest that regional isostatic compensation of the Solomons has occurred. However, the gravity fields of the individual islands suggest significant departures from isostasy. These are attributed to: support of Quaternary volcanic piles by the strength of the earth's crust without isostatic compensation; higher than normal crustal densities; and upwarping of the mantle beneath the islands.