Bathymetry and geophysics of the Snellius-II triple junction and tentative seismic stratigraphy and neotectonics of the northern Aru Trough
Jongsma, D.; Huson, W.; Woodside, J.M.; Suparka, S.; Sumantri, T.; Barber, A.J. (1989). Bathymetry and geophysics of the Snellius-II triple junction and tentative seismic stratigraphy and neotectonics of the northern Aru Trough. Neth. J. Sea Res. 24(2-3): 231-250
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, more
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| Authors | | Top |
- Jongsma, D.
- Huson, W.
- Woodside, J.M.
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- Suparka, S.
- Sumantri, T.
- Barber, A.J.
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| Abstract |
The NNE trending 3.6 km deep Aru Trough and the NW trending 2 km deep Seram Trough form two active branches of a triple junction between the Banda Sea, the Australian continent and the Irian Java microplate. A marine geophysical survey of this junction shows that between the termination of these two branches is a triangular area some 200 km in the east-west direction and 100 km in the north-south direction with several ridges and troughs that have a relief of 2 to 3 km. East of a north-south trending Banda deformation front, expressed as an inactive trench between the Kai islands and the southwestern tip of Irian Jaya, the survey delineates: a. a N-S trending 80 km long and 20 km wide ridge (Kuenen Ridge); b. a 2600 m deep trough (Adi Trough); c. a 2000 m deep east-west fracture zone, some 50 km long and 10 km wide, which cuts off the Kuenen Ridge west of Adi Island; d. a NE trending complex slope with troughs and ridges that forms the northwestern margin of the Aru Trough between Adi Island and the Bird's Neck. The observed high resolution seismic stratigraphy, which is tentatively correlated with the latest version of the cycle chart points to an 1100 m post-Oligocene gently deformed sedimentary section in the Adi Trough. Very thick post-late Pliocene sediments (750 m) occur in the Aru Trough. These latter sediments show complex sequence boundaries in the northern Aru Trough, caused by rapid sedimentation in an active strike-slip zone. Based on the tentative ages of sequence boundaries in the area we derive an age of just after 3 Ma for the start of wrenching in the area. The tectonic activity and the structures produced are postulated to be related to the wrenching observed along the southern end of the Lengguru Fold Belt. |
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