地质学

长江中下游地区晚中生代橄榄玄粗岩系列火山岩：年代学格架、地球化学特征及成因讨论

薛怀民，马芳，曹光跃，等

长江中下游地区晚中生代橄榄玄粗岩系列火山岩发育在宁芜、庐枞、溧水和怀宁四个火山岩盆地内，该系列的火山岩地球化学性质上以相对富碱、高K、明显富集Rb、Th、U、K等强不相容元素和轻稀土元素，亏损高场强元素Nb、Ta和Ti为特征。Ba和Sr的特征在不同盆地内随岩性的不同表现各异，表明斜长石的分离结晶可能在这些盆地内岩浆演化过程中起着一定的作用。这些盆地内橄榄玄粗岩系列火山岩的部分地球化学性质（如Ce/Yb比值）与大多数发育在大陆环境下的橄榄玄粗岩系列岩石不同，而类似于大洋岛弧环境内的同类岩石，可能意味着区内由于岩石圈的减薄，软流圈地幔上涌到了相对较浅的部位，控制源区部分熔融的主要是尖晶石相地幔岩。这些火山岩的Sr、Nd同位素组成总体处于扬子克拉通岩石圈地幔附近，指示它们的母岩浆主要是由富集的岩石圈地幔部分熔融形成的。但盆地所处的构造位置对岩浆的性质也有显著的影响，指示地壳基底物质的混染也不同程度存在。区内榄玄粗岩系列火山活动持续的时间很短，主要集中在约128～134 Ma左右，峰值约130 Ma，其成因的动力学机制可能与晚中生代发生在中国东部的岩石圈减薄事件有关，橄榄玄粗岩系列火山岩盆地所在地带对应着长江中下游地区岩石圈减薄的中心部位。

关键词：橄榄玄粗岩系列；SHRIMP锆石U-Pb定年；岩石圈减薄；晚中生代；长江中下游地区

来源出版物：地质学报, 2015, 89(8): 1380-1401联系邮箱：薛怀民，huaiminx@sina.com

来源出版物：Acta Geologica Sinica (English Edition), 2015, 89(4): 1319-1332联系邮箱：DIAO Yu-jie, diaoyujie1983@163.com

Potential and suitability evaluation of CO2geological storage in major sedimentary basins of China, and the demonstration project in Ordos Basin

GUO Jian-qiang, WEN Dong-guang, ZHANG Sen-qi, et al.

From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey (CHEGS) carried out the project “Potential evaluation and demonstration project of CO2Geological Storage in China”. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2geological storage based on China’s geological conditions, and evaluated the potential and suitability of the primary basins for CO2geological storage, in order to draw a series of regional scale maps (at a scale of 1 : 5000000) and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2storage. We also built techniques and methods for site selection and the exploration and assessment of CO2geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2storage in deep saline aquifers under China’s geological conditions.

CO2geological storage; potential and suitability evaluation; atlas; demonstration project