南海北部东沙西南海域泥火山的流体特征及其活动历史

Mud volcanoes have been highly concerned because of their important resources and environment significance. The mud volcano of southwestern Dongsha in the northern South China Sea is a newly discovered activity mud volcanoes with hundreds of square kilometers. Some indications show that it is likely to be an important gas hydrate potential area. But only some preliminary geophysical researches are currently carried out about this mud volcanoes. Its fluid characteristics including origin and composition of gas are still lack of basic understanding, its activities history and rules is also not clear, and its formation causes and mechnisms still need to be in-depth studied. The authigenic carbonates from seabed, bottom sea water, and representative sediment cores collected from this mud volcanoes area will be selected to be specific research materials in this project. The fluid charateristics and activities history of this mud volcanoes will be comprehensive analyzed, its formation mechanisms and environmental effects will be further revealed, and the internal relationship between mud volcanoes and gas hydrate will also be discussed based on characteristic physical and chemical indicators and dating of minerals and AMS14C of foraminifera. The expected research has important sicentific significance for deepening understanding global climate and environment change and the formation processes and mechanisms of cold seep in the seafloor, and also can provide important clues and evidences for geological exploration and potential evaluation of gas hydrate in this area.

泥火山因其重要的资源与环境意义而受到高度关注。南海北部东沙西南海域泥火山是新近发现的一个面积达数百平方公里的活动泥火山群，有迹象表明它很可能是一个重要的天然气水合物潜在区。但针对该泥火山群目前仅从地球物理角度开展了一些初步的调查研究，对它的气体来源和组成等流体特征尚缺乏基本认识，对其活动历史和规律更不清楚，其形成原因和机制有待深入研究。本项目拟以该泥火山群所在海域的海底自生碳酸盐岩、底层水和代表性沉积物柱样等为具体研究材料，在特征理化指标分析及矿物和有孔虫定年基础上，综合分析该泥火山群的流体特征及活动历史，进一步揭示该泥火山群的形成机制和环境影响，并探讨其与海底天然气水合物之间的内在关系。预期研究成果对深化认识全球气候环境变化以及海底冷泉系统的形成过程和机制具有重要的科学意义，同时也可为该海域天然气水合物地质勘探和潜力评价提供重要线索和依据。

南海北部东沙西南海域具有泥火山发育的有利构造特征，对已识别到的典型泥火山群，目前仅通过地球物理资料初步确定了其分布和形态特征及可能的构造成因，对它的气体来源和组成等流体特征尚缺乏基本认识，对其活动历史和规律更不清楚，其形成原因和机制有待深入研究。而该泥火山成群成带分布、仍在活动以及海底冷泉碳酸盐岩的发育等系列重要特征，为开展其气源和流体组成及活动历史研究提供了良好条件，也是探讨泥火山与天然气水合物成因联系的典型区域。本项目通过获取该泥火山群所在海域的自生碳酸盐岩及代表性柱状沉积物等样品和材料，对该泥火山群的流体地球化学特征开展系统研究，并结合自生碳酸盐岩及柱样沉积物中的有孔虫定年，综合分析了该泥火山群的流体特征及活动历史和规律，探讨了其形成过程及与天然气水合物和冷泉系统的关系，以深化认识泥火山的形成机制及其资源环境意义，并为该海域天然气水合物地质勘探和潜力评价提供了重要线索和依据。