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Controls on turbidite deposition offshore the Chilean convergent margin

对智利辐合边缘近海浊积岩沉积的控制

基本信息

批准号：
216660054
负责人：
Professorin Dr. Anne Bernhardt
金额：
--
依托单位：
Institut für Geologische Wissenschaften
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/216660054?language=en
关键词：
Controls turbidite deposition offshore Chilean

项目摘要

Recurrence rates of giant subduction-zone earthquakes are still highly uncertain on centennial to millennial time scales along the rupture zone of the recent Chilean earthquake (Maule region, 2/27/2010; M=8.8), but are of utmost importance for seismic hazard prediction. Turbidite frequency has been used to reveal earthquake recurrence intervals along seismically hazardous continental margins but these results are still strongly debated. Only if the controls on turbidite deposition are well understood, the compilation of a turbidite paleoseismologic record can be successful. To establish recurring seismicity as a trigger for turbidity currents, synchronous deposition of turbidites in widely spaced, isolated depocenters has to be demonstrated. The main purpose of this study is to evaluate the relative contributions and history of controls on Holocene turbiditic sediment flux within two climatic zones along the Chilean margin. The development of a holistic model of deep-marine sedimentation focusing on terrestrial and submarine components and their interactions will allow to evaluate the feasibility of compiling a turbidite paleoseismologic record. If the Chilean margin proves to be a suitable place, such a record for two seismotectonic segments will be compiled. The proposed approach entails obtaining: (1) robust geochronologic constraints of the timing of turbidite layers, (2) correlation of turbidite ages and depositional rates to records of on- and offshore forcings, and (3) to test for coeval turbidite deposition in 7 depocenters to compile a paleoseismologic record for the Maule (34º-38ºS) and an adjacent rupture zone (30º-32ºS).

巨型俯冲带地震的复发率仍然是高度不确定的百年至千年的时间尺度沿着最近智利地震（马乌莱地区，2010年2月27日; M=8.8）的破裂带，但地震危险性预测是至关重要的。浊积岩频率已被用来揭示地震复发间隔沿着地震危险的大陆边缘，但这些结果仍然有很大的争议。只有了解浊流沉积的控制因素，才能使浊流古地震记录的编制取得成功。要建立作为浊流触发器的重复性地震活动，必须证明浊流在间隔较宽的孤立沉积中心的同步沉积。本研究的主要目的是评估相对贡献和历史的控制全新世浊流沉积物通量在两个气候带沿着智利边缘。开发一个以陆地和海底成分及其相互作用为重点的深海沉积整体模型，将有助于评估编制浊流古地震记录的可行性。如果智利边缘被证明是一个合适的地方，这样一个记录的两个地震构造段将被汇编。所提出的方法需要获得：（1）浊积岩层形成时间的强大地质年代学约束，（2）浊积岩年龄和沉积速率与陆上和海上强迫记录的相关性，以及（3）测试7个沉积中心的同时代浊积岩沉积，以编制Maule（34º-38 playS）和邻近破裂带（30º-32 playS）的古地震记录。