On the Age of the Granitic Rocks in Relation to the Structural Features of Sumatra

  1. Gordon A. Macdonald and
  2. Hisashi Kuno
  1. John A. Katili

Published Online: 21 MAR 2013

DOI: 10.1029/GM006p0116

The Crust of the Pacific Basin

The Crust of the Pacific Basin

How to Cite

Katili, J. A. (2013) On the Age of the Granitic Rocks in Relation to the Structural Features of Sumatra, in The Crust of the Pacific Basin (eds G. A. Macdonald and H. Kuno), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM006p0116

Author Information

  1. Geological Department, Institute of Technology, Bandung, Indonesia

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1962

Book Series:

  1. Geophysical Monograph Series

Book Series Editors:

  1. Waldo E. Smith

ISBN Information

Print ISBN: 9780875900063

Online ISBN: 9781118669310

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Keywords:

  • Andesitic volcanic activity;
  • De Hann's age determination;
  • Granitic masses;
  • Mesozoic diastrophism;
  • Structural features of Sumatra

Summary

The age of the different granitic rocks in central and other parts of Sumatra have been studied in relation to the structural feature of the area. Most of the granites are of post-Triassic and pre-Tertiary age, but some granites in southern Sumatra are of Cretaceous age. In central Sumatra only one definite unconformity exists between the Triassic and Tertiary deposits. Consequently, based on field data alone no accurate age of the folding phase can be established. The absolute age of the so called Lassi granites in central Sumatra has been found to be 112±24 million years, which places the formation of this granite, and consequently the age of the folding, in middle Cretaceous. A distinct zonal arrangement of the granites according to age can be observed in south Sumatra, however this zonal structure should not be used conversely as a base to establish the age of the granites or the folding either in central or other parts of Sumatra.