14. Sedimentation at Plate Boundaries in Transition

  1. Cathy Busby2 and
  2. Antonio Azor3
  1. Kathleen M. Marsaglia

Published Online: 30 JAN 2012

DOI: 10.1002/9781444347166.ch14

Tectonics of Sedimentary Basins: Recent Advances

Tectonics of Sedimentary Basins: Recent Advances

How to Cite

Marsaglia, K. M. (2011) Sedimentation at Plate Boundaries in Transition, in Tectonics of Sedimentary Basins: Recent Advances (eds C. Busby and A. Azor), John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9781444347166.ch14

Editor Information

  1. 2

    Department of Earth Science, University of California, Santa Barbara CA 93106, USA

  2. 3

    Departamento de Geodinámica, Universidad de Granada, Campus de Fuentenueva, s/n, 18071 Granada, Spain

Author Information

  1. Department of Geological Sciences, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8266, USA

Publication History

  1. Published Online: 30 JAN 2012
  2. Published Print: 30 DEC 2011

ISBN Information

Print ISBN: 9781405194655

Online ISBN: 9781444347166

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Keywords:

  • subduction initiation, spontaneous, induced;
  • triple junction;
  • sedimentation;
  • ophiolite obduction

Summary

From inception to termination convergent margins are dynamic regions. Subduction initiation is poorly understood with arguments for both induced and spontaneous processes. Geodynamic models help to predict the sedimentary-volcanic records of such events, but there are few areas where these models have been tested, particularly pre-Cenozoic examples. Where subduction is induced, the sedimentary signatures should include evidence for rapid uplift (unconformity), then rapid subsidence (finingand deepening-upward succession), followed by building of the arc edifice. Where subduction is spontaneous, the proto-forearc experiences subsidence and early magmatism prior to development of the magmatic arc. Once initiated, there are other opportunities for tectonic overprinting of the forearc owing to the formation and migration of plate triple junctions. There are several well-studied modern to Cenozoic examples that suggest differing signatures depending on the plate configuration. In the case of a triple junction involving purely subduction (trench-trench-trench) the overriding signature is associated with arc terrane accretion, whereas the interaction of a spreading ridge at a trench-ridge-trench triple junction can result in anomalous neartrench magmatism, thermal overprinting of the forearc, and subduction erosion. In triple-junction cases where subduction is superceded by transform plate motion (e.g., trench-fault-fault) the transition is marked by progressive uplift and deformation of the forearc concomitant with cessation of arc magmatism. The demise of a convergent margin can be through simple abandonment and subsidence, or transition to a transform plate margin, or where a spreading ridge is involved, result in deformation, uplift, and thermal/volcanic overprinting of the forearc prior to abandonment.