The Bengal Fan stratigraphy as a function of tectonic and climate - Correlation of IODP Expedition 354 results and available seismic data from the Bay of Bengal

孟加拉扇地层作为构造和气候的函数 - IODP Expedition 354 结果与孟加拉湾可用地震数据的相关性

• 批准号: 260964306
• 负责人: Dr. Tilmann Schwenk
• 金额: --
• 依托单位: Fachgebiet Meerestechnik - Umweltforschung
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/260964306?language=en
• 关键词: Bengal; Fan; stratigraphy; function; tectonic

The Bengal Fan, which covers the entire Bay of Bengal, is the most complete recorder for the erosional history of the Himalayans. Consequently the sedimentation on the fan is controlled by the growth of the Himalaya/Tibetan system, the past evolution of the regional climate and their interactions. Therefore IODP Expedition 354 (Bengal Fan) is dedicated to study (1) the early stage of Himalayan erosion generated by the development of the Himalaya and Tibet as topographic features and (2) the Neogene history of the Asian monsoon and its impact on sediment supply and flux. The expedition was carried out in February/March 2015, co-chief scientists were C. France-Lanord and the V. Spiess. During Expedition 354 seven sites were drilled on a East-West transect at 8°N. This drilling strategy also allows determining the lateral depocenter migration typically for submarine fans, and utilizing this result during interpretation of drilling results.In the frame of this renewal proposal it is proposed to correlate results from IODP Expedition 354 and the available seismic data net from two pre-site surveys (RV Sonne cruises SO125 and SO188) in the Bay of Bengal to establish a new stratigraphy for the Bengal Fan with respect to the regional tectonic and climatic evolution. The existing stratigraphy bases a) on poor age constraints from the just spot-cored DSDP Site 218 and b) only on seismic data gathered during Cruise SO125 around 8°N. Including all available data from Cruise SO188 will extend the stratigraphy to 11°N. New dating of stratigraphic features will give new, significant insights into the build-up of the fan as a function of the histories of the Himalaya/Tibetan system and the Asian monsoon. Finally this project shall improve the general understanding of processes controlling soure-2-sink systems.In the running project phase all available seismic data were (re)-processed. A seismo-stratigraphic analysis is already ongoing and shall be continued with respect to the drilled dated hemipelagic layer to finally establish a robust regional stratigraphy. Objectives of the following interpretation will be the exact determination of the onset of channel-levee systems on the Bengal Fan, the identification of succession and average lifetimes of individual channel-levee systems for dated time slices, and the study of variations of fan architecture from north to south within these different time slices. All these results will be utilized in the budgeting of sediment fluxes, and are of significant relevance for the IODP Exp. 354 community, since results from single drill holes have to be assessed in the light of this lateral highly-dynamic system

覆盖整个孟加拉湾的孟加拉扇是喜马拉雅山侵蚀历史最完整的记录器。因此，扇上的沉积受喜马拉雅/藏系的发育、区域气候的过去演化及其相互作用的控制。因此，IODP考察队354(孟加拉扇)致力于研究(1)喜马拉雅和西藏发展所产生的喜马拉雅早期侵蚀的地形特征；(2)亚洲季风的新近纪历史及其对沉积物供应和通量的影响。这次探险是在2015年2月/3月进行的，联合首席科学家是C.France-Lanord和V.Spiess。在354次勘探期间，在北纬8°的东西断面上钻探了7个地点。这种钻井策略还允许确定典型的海底扇区的横向沉积中心迁移，并在解释钻井结果时利用这一结果。在这个更新建议的框架内，建议将IODP 354勘探的结果与孟加拉湾两次站前调查(RV Sonne邮轮SO125和SO188)的现有地震数据网相关联，以建立关于区域构造和气候演化的孟加拉扇新地层学。现有地层学的基础是a)来自刚刚取了点岩心的DSDP站点218的较差的年龄限制和b)仅基于在SO125号邮轮期间收集的北纬8°左右的地震数据，包括来自SO188邮轮的所有现有数据将把地层学扩展到北纬11°。最后，该项目将提高对震源-2-汇系统控制过程的总体理解。在运行项目阶段，对所有可用地震数据进行(重新)处理。地震地层学分析已经在进行中，并将继续对钻探的过时的半深海层进行分析，以最终建立健全的区域地层学。以下解释的目标将是准确确定孟加拉扇上河道-堤防系统的起始时间，识别单个河道-堤防系统的演替和平均寿命，以及研究这些不同时间片内从北到南的扇体结构变化。所有这些结果都将用于沉积物通量的预算，并对IODP Exp具有重要意义。354社区，因为单个钻孔的结果必须根据这个横向高度动态的系统进行评估

项目成果

MAGNETIC FABRIC AND CHANNEL MIGRATION IN THE ACTIVE LEVEE OF THE BENGAL FAN, IODP SITE U1454

IODP 站点 U1454 孟加拉风扇活动堤中的磁性织物和通道迁移

• DOI: 10.1130/abs/2017am-305063
• 发表时间: 2017
• 作者: Selkin;Bergmann;Brainard;Dekens;Lantzsch;Manzueta Jr;Meynadier;Reilly;Ruiz III;Savian;France-Lanord;Spiess
• 通讯作者: Spiess