Mountains by Park Graham

Author:Park, Graham
Language: eng
Format: epub
Publisher: Dunedin Academic Press Limited
Published: 2018-10-14T16:00:00+00:00

Figure 9.5 The offshore Sunda Arc. Simplified topographic section based on refraction seismic data across the western part of the arc, showing the accretionary prism. Lower higher-density part of the prism in orange; upper, lower-density material in yellow; oceanic sediments in blue. After Kopp, 2011.

Figure 9.6 Main plate-tectonic elements of Central and Eastern Indonesia. ‘Sundaland’ represents the extent of stable Eurasian crust added in the Cretaceous to the northern side of the Cenozoic orogenic belt system. ESul, East Sulawesi; IBA, Inner Banda Arc; NSul, North Sulawesi; PH, Philippines; SSul, South Sulawesi; Sula, Sulawesi; WSul, West Sulawesi. After Hall, 2011.

Tectonic context

The region of Indonesia east of Sumba island, including Sulawesi, Timor, the western part of New Guinea, and the many smaller islands, is one of the most structurally complex of the whole Cenozoic orogenic belt system. The main reason for its complexity is its position at the junction of three plates: the continental part of the large Australian Plate to the south, Sundaland (part of Eurasia) to the west, and the oceanic Philippine Sea Plate to the east and north.

Figure 9.7 is a reconstruction of how the plate-tectonic framework of Eastern Indonesia evolved during the Neogene. During the Palaeogene Period, oceanic parts of two plates, the Indian and Australian Plates, were being subducted beneath Southeast Asia and the Philippine Sea Plate respectively, and the plate boundary network then was relatively simple. However, as the Australian continent approached Southeast Asia in the Miocene, as illustrated in Figure 9.7A, the shape of the northern margin of Australia became critical: the first point of contact was a large spur, the Sula Spur, which projected north-westwards from the western end of New Guinea. This NW–SE promontory contained the western part of New Guinea together with Seram, Southern and Eastern Sulawesi, and many smaller islands. Elsewhere, the oceanic part of the Australian Plate on the northeast side of New Guinea was being subducted beneath the Philippine Sea Plate to form the volcanic arcs of North Sulawesi, the Philippines and Halmahera, and the oceanic crust on the western side of the Australian Plate had not yet made contact with the Banda Arc.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.