我国东部海域末次盛冰期以来沉积格局的物源控制和沉积物收支

Sediment source is the main controlling factor of sediment accumulation, and the premise of quantitively sediment source analysis is the balance of sediment budget. This project will mainly focus on the sediment source and budgets during the late Quaternary in the East China Seas, and take the sanydy, transisional, and muddy sediments on the seafloor as a whole system. We will firstly classfy the late Quarternary sediments in terms of sequence stratigraphy into low-stand system tract, transgressional system tract, and high stand system tract. The geophysical (shallow strata profile) data and the sediment cores conducted in the recent 10 years will be integrated as the basic dataset for the study. Piston cores and shaow drilling cores will be also utilized for the sequence analysis and paleoenvironment reconstrction. All the information will be used for a 3 dimensional model setup for the sequence distribution and construction. Furthermore, we will analyze the inter-relationship between the formation of different deposits in different geological time and terrestrial inputs, sea level change, geomorphology, and current pattern. By using the multi-parameter analysis, we will further discuss and compare the sediment provenance of muddy, sandy and muddy sand/sandy mud deposits. Concerning the sediment budget analysis, we will quantitatively set up the data model for the budgets for the Late Quaternary sediments developed in such a large area. Finally, we will intend to reconstruct the sedimentation pattern during the last Quaternary in East China Seas. Significantly, this project will integrate recent investigation data and researches in this special area, and compare the sedimentation pattern with different shelves on earth, in order to enrich our understandings and knowledge on shelf sedimentology.

物源是控制沉积物堆积的重要因素，沉积物定量化物源分析的前提是收支平衡。本项目拟从物源控制和沉积物收支平衡的角度出发，将东部海域看作一个大的沉积系统，选择重点海域，采用层序地层学的方法，划分末次盛冰期以来（或2万年）沉积成因类型；整合和利用我国近年来在东部海域开展的地球物理和地质资料，辅以必要的测试，建立我国东部海域末次盛冰期以来三维地层结构和成因模型；研究不同类型沉积体的形成与河流输入（量）、海平面和可容纳空间的变化及底形、流场等沉积动力学因素的关系；选择有效参数，开展泥质、过渡（泥-砂质）、砂质沉积的物源判别；采用沉积物收支理论和方法，基于GIS处理和3D古地形分析，估算现今-7000年-14500年-20000年等3个地质时期阶段沉积物收支状况，阐明不同历史时期沉积物输运和堆积的格局变化规律，建立基于沉积收支平衡的定化物源判别模型，丰富陆架沉积学理论。

依据海量资料，建立了中国海域晚第四纪地层框架，阐明了我国海域10万年以来沉积环境演化特征，揭示出3个典型的海相地层，精细示踪了陆源物质在海区的分布，建立了表层沉积物动力驱动模式，为全球沉积环境演化提供区域性理论支持。秉持从源到汇的理念，从流域产沙到陆架搬运，从世界大河（长江、黄河）到局部小河（鸭绿江），考虑的时间尺度也从季节性到轨道尺度，影响因素涉及人类活动和气候变化，通过这些综合工作，对不同时空尺度我国东部陆架海的源汇过程的变化有了进一步的了解。对我国东部陆架海各个典型海域柱状沉积物开展了多参数的定量化物源分析，在结合他人工作基础上，基本恢复了末次冰盛期以来的沉积格局。