地質(zhì)學(xué)

長江中下游地區(qū)晚中生代橄欖玄粗巖系列火山巖：年代學(xué)格架、地球化學(xué)特征及成因討論

薛懷民，馬芳，曹光躍，等

長江中下游地區(qū)晚中生代橄欖玄粗巖系列火山巖發(fā)育在寧蕪、廬樅、溧水和懷寧四個火山巖盆地內(nèi)，該系列的火山巖地球化學(xué)性質(zhì)上以相對富堿、高K、明顯富集Rb、Th、U、K等強不相容元素和輕稀土元素，虧損高場強元素Nb、Ta和Ti為特征。Ba和Sr的特征在不同盆地內(nèi)隨巖性的不同表現(xiàn)各異，表明斜長石的分離結(jié)晶可能在這些盆地內(nèi)巖漿演化過程中起著一定的作用。這些盆地內(nèi)橄欖玄粗巖系列火山巖的部分地球化學(xué)性質(zhì)（如Ce/Yb比值）與大多數(shù)發(fā)育在大陸環(huán)境下的橄欖玄粗巖系列巖石不同，而類似于大洋島弧環(huán)境內(nèi)的同類巖石，可能意味著區(qū)內(nèi)由于巖石圈的減薄，軟流圈地幔上涌到了相對較淺的部位，控制源區(qū)部分熔融的主要是尖晶石相地幔巖。這些火山巖的Sr、Nd同位素組成總體處于揚子克拉通巖石圈地幔附近，指示它們的母巖漿主要是由富集的巖石圈地幔部分熔融形成的。但盆地所處的構(gòu)造位置對巖漿的性質(zhì)也有顯著的影響，指示地殼基底物質(zhì)的混染也不同程度存在。區(qū)內(nèi)欖玄粗巖系列火山活動持續(xù)的時間很短，主要集中在約128～134 Ma左右，峰值約130 Ma，其成因的動力學(xué)機制可能與晚中生代發(fā)生在中國東部的巖石圈減薄事件有關(guān)，橄欖玄粗巖系列火山巖盆地所在地帶對應(yīng)著長江中下游地區(qū)巖石圈減薄的中心部位。

關(guān)鍵詞：橄欖玄粗巖系列；SHRIMP鋯石U-Pb定年；巖石圈減薄；晚中生代；長江中下游地區(qū)

來源出版物：地質(zhì)學(xué)報, 2015, 89(8): 1380-1401聯(lián)系郵箱：薛懷民，huaiminx@sina.com

來源出版物：Acta Geologica Sinica (English Edition), 2015, 89(4): 1319-1332聯(lián)系郵箱：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