Sediment loading at the southern Chilean trench and its tectonic implications |
| |
| Institution: | 1. Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan;2. Hydrographic and Oceanographic Department, Japan Coast Guard, 3-1-1, Kasumigaseki, Chiyoda-ku, Tokyo 100-8932, Japan;1. Faculty of Engineering, China University of Geosciences, Wuhan 430074, China;2. Key Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;3. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China;4. Chinese Academy of Geological Sciences, Beijing 100037, China;5. MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, Guangzhou 510075, China |
| |
| Abstract: | Non erosive margins are characterized by heavily sedimented trenches which obscure the morphological expression of the outer rise; a forebulge formed by the bending of the subducting oceanic lithosphere seaward of the trench. Depending on the flexural rigidity (D) of the oceanic lithosphere and the thickness of the trench sedimentary fill, sediment loading can affect the lithospheric downward deflection in the vicinity of the trench and hence the amount of sediment subducted. We used seismic and bathymetric data acquired off south central Chile, from which representative flexural rigidities are estimated and the downward deflection of the oceanic Nazca plate is studied. By flexural modeling we found that efficient sediment subduction preferentially occurs in weak oceanic lithosphere (low D), whereas wide accretionary prisms are usually formed in rigid oceanic lithosphere (high D). In addition, well developed forebulges in strong oceanic plates behaves as barrier to seaward transportation of turbidites, whereas the absence of a forebulge in weak oceanic plates facilitates seaward turbidite transportation for distances >200 km. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
