Reconstructing the evolution of the Bengal Fan with physical properties (ReconFan)

ReconFan项目依赖于我以前关于孟加拉扇不同环境的工作和出版物，以及由此产生的知识空白。重点在于IODP远征354期间收集的沉积物物理和光学性质数据。总体目标是：(i)揭示由于喜马拉雅侵蚀和亚洲季风发展的相互作用而导致的下扇浊积和半深海沉积的历史，（ii）通过轨道调整、生物磁学地层学和灰分鉴定提供高分辨率的年龄控制，以及（iii）研究不同时间尺度上对气候和季风强迫的响应。目前的资金已部分实现了这些目标，并编写了三份手稿：其中一份正在审查中，第二份已准备提交，第三份已接近完成。在续期期间，应当结束正在进行的调查，并采用尚未使用的新方法。以第一作者身份发表至少两篇以上论文。对于更新世剖面，在古地磁和生物地层学约束下，建立了基于轨道校正和光谱分析的年龄模型。此外，傅里叶变换红外光谱已被用于确定散装地球化学。这两种方法现在应扩展到上新世-中新世剖面。具体来说，需要对沉积物的物理性质（湿容重、压缩波速和磁化率）和光学性质（LaCie L*、a*、b*反射色）进行处理，以确定沉积相，即通过地球化学定标确定沉积物中三种主要成分碎屑、生物成因欧泊和生物成因碳酸盐的相对比例。采用一种新的颜色反射方法，即Q4/7分析，来测试是否可以根据地球化学性质来区分相变化。碎屑组分的砂、粉和粘土的相对比例应根据粒度测定来确定，从而为浊积岩提供高度分辨的沉积物预算。调查的最终目标是获得重要的信息，以揭示侵蚀历史和通过恒河-雅鲁藏布江水系的相关河流运输量，沉积中心的迁移与海平面变化有关，以及记录在下孟加拉扇上的季风和气候的长期变化。

The Project ReconFan relies on my previous work and publications on different environments of the Bengal Fan and the resulting gaps in knowledge. The focus lies on sediment physical and optical property data collected during IODP Expedition 354. General objectives are to (i) unravel the history of turbiditic and hemipelagic deposition on the lower fan as a result of the interplay of Himalayan erosion and Asian monsoon development, (ii) provide high-resolution age control through orbital tuning, biomagnetostratigraphy, and ash identification, and (iii) study the response to climate and monsoon forcing on different time scales. These objectives have partially been fulfilled with the current funding, and three manuscripts have been compiled: one of which is under review, the second one is ready for submission, and the third one is near completion. During the renewal period, ongoing investigations shall be concluded and new, so far not used methods shall be employed. At least two more papers as first author shall be published. For the Pleistocene sections, age models based on orbital tuning and spectral analysis were constructed for all Expedition 354 sites, with the aid of paleomagnetic and biostratigraphic constraints. Also, Fourier Transform Infrared Spectroscopy has been used to determine bulk geochemistry. Both of these methods shall now be expanded to Plio-Miocene sections. Specifically, sediment physical (wet-bulk density, compressional-wave velocity, and magnetic susceptibility) and optical (LaCie L*, a*, b* reflectance color) properties shall be processed to assign sediment facies, i. e. determine, through geochemical calibration, the relative proportions of the three major sediment components detritus, biogenic opal, and biogenic carbonate. A novel color reflectance method, the so-called Q4/7 analysis shall be employed to test if facies variations can be discriminated based on geochemical properties. Relative proportions of sand, silt, and clay shall be determined for the detrital fraction, based on grain-size determinations, to provide highly-resolved sediment budgets for turbidites. The ultimate goals of the investigations are to obtain vital information to unravel the erosional history and the associated amount of fluvial transport via the Ganges Brahmaputra river systems, the depocenter migration with respect to sea-level changes, and the long-term changes in monsoon and climate as documented on the Lower Bengal Fan.