| 渤海湾盆地晚中生代以来伸展模式及动力学机制 |
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| 引用本文： | 赵利,李理.渤海湾盆地晚中生代以来伸展模式及动力学机制[J].中国地质,2016(2):470-485. |
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| 作者姓名： | 赵利 李理 |
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| 作者单位： | 同济大学海洋与地球科学学院, 上海 200092;中石化石油勘探开发研究院无锡石油地质研究所, 江苏 无锡 214216;中国石油大学地球科学与技术学院, 山东 青岛 266580,中国石油大学地球科学与技术学院, 山东 青岛 266580 |
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| 基金项目： | 国家自然科学基金项目(40772132)资助. |
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| 摘 要： | 通过分析盆地区大陆伸展模型参数、火成岩地球化学特征时空演化、岩石圈分层伸展几何学和运动学、应力场-变形场的匹配和演化,文章对渤海湾盆地晚中生代以来伸展断陷的动力学过程进行了系统讨论。晚中生代,盆地北、西部以变质核杂岩模式伸展,南、东部以宽裂陷模式伸展;在岩石圈伸展过程中,地壳变形方式为简单剪切,岩石圈地幔变形方式为纯剪切;盆地处于洋壳俯冲背景下弧后伸展区,盆地及西、北部隆起区岩石圈地幔为EM1型,而南、东部隆起区受扬子板块俯冲改造成类似EM2型;盆地变形的力源为板块相对运动产生的引张力,以及郯庐断裂的走滑作用。新生代,渤海湾盆地以窄裂陷模式伸展,地壳和岩石圈地幔变形方式均为纯剪,但岩石圈地幔伸展强度大于地壳;盆地处于大陆内裂谷环境,软流圈地幔上涌并改造岩石圈地幔,且盆地裂陷的力源以软流圈地幔上涌产生的引张力为主。
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| 关 键 词： | 大陆伸展 火成岩 应力场 晚中生代-新生代 渤海湾盆地 |
| 收稿时间： | 2015/4/15 0:00:00 |
| 修稿时间： | 2015/10/18 0:00:00 |
The extensional pattern and dynamics of Bohai Bay basin in Late Mesozoic-Cenozoic |
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| ZHAO Li and LI Li.The extensional pattern and dynamics of Bohai Bay basin in Late Mesozoic-Cenozoic[J].Chinese Geology,2016(2):470-485. |
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| Authors: | ZHAO Li and LI Li |
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| Institution: | School of Ocean & Earth Science, Tongji University, Shanghai 20092, China;Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi 214126, Jiangsu, China;School of Geosciences, China University of Petroleum, Qingdao 266580, Shandong, China and School of Geosciences, China University of Petroleum, Qingdao 266580, Shandong, China |
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| Abstract: | Based on analyzing the model parameters of continental extension, the temporal-spatial evolution of igneous rock''s geochemical characteristics, the geometry and kinematics of multi-level extension within lithosphere , the match and evolution between stress and deformation fields, this paper focuses on the Bohai Bay basin and its adjacent areas to discuss the dynamic mechanism of rifting in Late Mesozoic-Cenozoic. The continent extended by the way of core complex mode in the north and west of Bohai Bay basin, but by the way of wide rift mode in the south and east in Late Mesozoic. In the process of lithospheric extension, the crust was deformed by simple shear whereas the lithospheric mantle deformed by pure shear. In addition, the geochemical characteristics of igneous rock indicate that the basin was located in a back-arc tensional regime due to the subduction of ocean crust, the lithospheric mantle was of EM1 pattern under the basin and in its north and west, whereas the lithospheric mantle was of the EM2-like pattern in the south and the east of the basin because of the subduction of Yangtze plate. Combined with the stress and deformation fields of the basin, the stress source of rifting should be the tension mainly generated by the relative motion within the plate, and the basin was transformed by the strike slip of Tanlu fault. However, the continent extended by the way of narrow rift mode within Bohai Bay basin in Cenozoic. Additionally, the crust and the lithospheric mantle were deformed exclusively by pure shear, but the latter extended more intensively. On the other hand, the geochemical characteristics of igneous rocks indicate that the basin was involved in the continental rift, and the asthenosphere upwelled and transformed the lithospheric mantle. Apparently, the tension produced by the upwelling of asthenosphere played the crucial role in basin rifting. |
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| Keywords: | continental extension igneous rock stress field Late Mesozoic-Cenozoic Bohai Bay basin |
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