南海北部洋陆过渡带的重力流沉积

根据IODP 367/368航次钻探取得的岩心和测井资料，结合高分辨率多道地震数据，研究南海北部洋陆过渡带重力流沉积物的类型、特征、分布及形成机理，为理解南海深海沉积环境演变及油气、水合物资源勘探提供依据。通过岩心观察、岩心X光照相、高密度取样分析（薄片、粒度、矿物成分等）及岩心物性和地化测试（磁化率、颜色反射率、有机碳等），研究重力流沉积物的类型及沉积特征；在岩心标定基础上，根据测井相分析预测未取心或低取心率井段重力流沉积的类型及分布；通过地震地层分析，结合年龄模式，建立区域等时层序地层对比格架，研究井间重力流沉积的横向分布及重力流事件的等时性；通过数值模拟估算重力流的流动参数（流速、浓度及流体厚度等）；综合岩心沉积学、测井相、地震地层与数值模拟研究，探讨重力流沉积的形成机理及其与区域构造、海底地形地貌演变、气候、海平面变化、物源供应等重要地质事件之间的成因联系。

The proposal attempts to investigate the types, sedimentary characteristics, tempo-spatial distribution, and formation mechanisms of various gravity-flow deposits (including turbidites, debrites, and submarine-landslide deposits) in the drilling area of IODP Expedition 367/368 at the northern continent-ocean transition of the South China Sea. By doing so, core, geophysical well-logging and seismic data will be integrated. The types and sedimentary characteristics of the gravity-flow deposits will be analyzed by various core sedimentological approaches, including core observations, core X-ray photographs, and thin-section, grain size and mineral composition analyses, as well as core measurements of associated physical and geochemical properties like magnetic susceptibility, density, lightness, and total organic carbon. Well-log facies analysis, calibrated by core data, will be used to detect the distribution of the gravity-flow deposits in the intervals with low core recovery or non-coring. Seismic stratigraphic analysis, tied to well control and constrained by geological age model, will provide a time-stratigraphic correlation framework for investigating the lateral distribution of the gravity-flow deposits and for evaluating the synchroneity of the various gravity-flow events. Flow behaviors of paleo-gravity flows will be quantitatively evaluated by numerical modeling. Integration of core-based sedimentology, well-log facies analysis, seismic stratigraphy, and numerical modeling will provide insights into the formation mechanisms of the gravity-flow deposits and the potential linkages to crucial geological events including regional tectonics, topographic variations, climate and sea level changes, and sediment supply.