The seismic structure of the Lombok and Savu forearc basins, Indonesia
van Weering, T.C.E.; Kridoharto, P.; Kusnida, D.; Lubis, S.; Tjokrosapoetro, S.; Munadi, S. (1989). The seismic structure of the Lombok and Savu forearc basins, Indonesia. Neth. J. Sea Res. 24(2-3): 251-262
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 Weering, T.C.E., meer
- Kridoharto, P.
- Kusnida, D.
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- Lubis, S.
- Tjokrosapoetro, S.
- Munadi, S.
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| Abstract |
High resolution seismic profiles correlated with industrial multichannel profiles of the Lombok and Savu forearc basins in Indonesia show that four seismic sequences can be recognized. These sequences are separated by unconformities that appear paraconformable in the western Lombok Basin. These unconformities had been dated earlier as late Oligocene, mid-Miocene and Pliocene in sections south of Java. The upper Miocene and Plio-Pleistocene forearc fill has a cyclic character, that marks the onset of a turbidite dominated depositional system. Interval velocity determinations allowed construction of isopachmaps for the lower/middle Miocene and for the upper Miocene to Recent forearc basin fill of the Lombok Basin. A maximum of 1600 m of lower/middle Miocene and about 2000 m of upper Miocene to Recent basin till is recorded in the western Lombok Basin. Faulting and tectonically induced deformation is strongest in the eastern Lombok Basin; growth faults, shale diapirs and mud volcano formation probably reflect the intensity of tectonic deformation caused by the mergence of the Sunda and Banda Arc collision systems. A series of tilted and uplifted basement ridges west of Sumba separates turbidite filled sub-basins from the forearc basin. Uplift of segments of these ridges, possibly associated with the uplift of Sumba caused large scale gravitational deformation and slumping of slabs of the sedimentary cover into the eastern Lombok forearc basin. Similarly, uplift and tilting of the Sumba Ridge east of Sumba resulted in sliding and slumping of its sedimentary cover down into the Savu Basin. The profiles suggest that Sumba was in its present position before onset of the subduction/collision system which created the Sunda and Banda Arcs and that the initial Lombok and Savu forearc basins were connected. |
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