Spatial geochemical variations of arc volcanism around the Banda sea
van Bergen, M.J.; Erfan, R.D.; Sriwana, T.; Suharyono, K.; Poorter, R.P.E.; Varekamp, J.C.; Vroon, P.Z.; Wirakusumah, A.D. (1989). Spatial geochemical variations of arc volcanism around the Banda sea. Neth. J. Sea Res. 24(2-3): 313-322
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
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| Auteurs | | Top |
- van Bergen, M.J.
- Erfan, R.D.
- Sriwana, T.
- Suharyono, K.
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- Poorter, R.P.E.
- Varekamp, J.C.
- Vroon, P.Z.
- Wirakusumah, A.D.
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| Abstract |
Active volcanoes of the eastern Sunda Arc and Banda Arc occur 100 to 250 km above the Benioff zone. These volcanoes have erupted an extremely wide range of lavas, from arc-tholeiitic (low-K) to leucite-bearing (alkaline) suites. Major and trace element results for ten volcanoes show systematic spatial variations along and across the arc system. For volcanoes with similar distance to the Benioff zone (100 to 150 km) on both sides of the inactive Alor-Romang segment the concentrations of potassium and other incompatible elements progressively increase in a direction towards the collision area near Timor. In the Adonara-Pantar segment close to Timor there is a further increase in these elements for volcanoes with increasing distance to the Benioff zone (100 to 250 km),i.e. in a northward direction away from the collision. No systematic correlations exist with the typical isotopic signatures that are indicative for the subduction of continent-derived material in this region. It is suggested that the arc-continent collision area near Timor is a local tectonic anomaly where arc volcanism is influenced not only by continental sediment/crust subduction but also by the geodynamic response to the collision event. |
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