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| 华南五峰组—龙马溪组与华北下马岭组的钾质斑脱岩及黑色岩系——两个地史转折期板块构造运动的沉积响应 | |
| 引用本文： | 苏文博,李志明,史晓颖,周洪瑞,黄思骥,刘晓茗,陈晓雨,张继恩,杨红梅,贾柳静,W.D.HUFF,F.R.ETTENSOHN.华南五峰组—龙马溪组与华北下马岭组的钾质斑脱岩及黑色岩系——两个地史转折期板块构造运动的沉积响应[J].地学前缘,2006,13(6):82-95. |
| 作者姓名： | 苏文博 李志明 史晓颖 周洪瑞 黄思骥 刘晓茗 陈晓雨 张继恩 杨红梅 贾柳静 W.D.HUFF F.R.ETTENSOHN |
| 作者单位： | 1. 中国地质大学(北京)地球科学与资源学院,北京,100083 2. 中国地质大学(武汉)地球科学学院,湖北,武汉,430074 3. 北京市第五十四中学,北京,100013 4. 中国科学院,研究生院,北京,100049 5. 美国辛辛那提大学,地质学系,辛辛那提,OH,45221-0013 6. 美国肯塔基大学,地球与环境科学系,列克星顿,KY,40506-0053 |
| 基金项目： | 国家自然科学基金;国家科委攀登计划专项SSER项目;国家重点实验室基金 |
| 摘 要： | 华南奥陶—志留纪之交的五峰组—龙马溪组及华北新元古界下马岭组发现的钾质斑脱岩,都产自类似的黑色硅质-碳质页岩/板岩岩系。这两套黑色岩系与上、下地层的接触关系、岩性组成以及垂向序列所揭示的地质过程,具有良好的可对比性,都符合Ettensohn总结的黑色页岩与板块构造运动之间的成因关系模式。岩石元素地球化学研究表明,这两组不同时代的钾质斑脱岩具有相似的源岩岩浆背景,为中酸性的粗安岩-英安岩-流纹岩系列,源于同碰撞岛弧(synCOL-VA)背景的火山喷发活动,与板块边缘的俯冲碰撞密切相关。由于华南五峰组—龙马溪组内斑脱岩及黑色页岩沉积的形成与此间华夏地块与扬子地块的汇聚相关,华北下马岭组的黑色岩系与钾质斑脱岩的形成可能也和华北地块与相邻地块的碰撞相关。推测后者很可能为Rodinia超大陆或Pangea850Ma汇聚时的沉积-地层学响应。 |
| 关 键 词： | 钾质斑脱岩 黑/暗色岩系 板块汇聚 早古生代 新元古代 华南和华北 |
| 文章编号： | 1005-2321（2006）06-0082-14 |
| 收稿时间： | 2006-04-15 |
| 修稿时间： | 2006-06-15 |
K-bentonites and black shales from the Wufeng-Longmaxi formations(Early Paleozoic, South China) and Xiamaling formation(Early Neoproterozoic, North China)-implications for tectonic processes during two important transitions |
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| SU Wen-bo,LI Zhi-ming,SHI Xiao-ying,ZHOU Hong-rui,HUANG Si-ji,LIU Xiao-ming,CHEN Xiao-yu,ZHANG Ji-en,YANG Hong-mei,JIA Liu-jing,W.D.HUFF,F.R.ETTENSOHN.K-bentonites and black shales from the Wufeng-Longmaxi formations(Early Paleozoic, South China) and Xiamaling formation(Early Neoproterozoic, North China)-implications for tectonic processes during two important transitions[J].Earth Science Frontiers,2006,13(6):82-95. | |
| Authors: | SU Wen-bo LI Zhi-ming SHI Xiao-ying ZHOU Hong-rui HUANG Si-ji LIU Xiao-ming CHEN Xiao-yu ZHANG Ji-en YANG Hong-mei JIA Liu-jing WDHUFF FRETTENSOHN |
| Abstract: | Recently, numerous K-bentonite beds have been recognized in the Wufeng-Longmaxi formations(Late Ordovician-Early Silurian) of South China and in the Xiamaling formation (~Tonian, Early Neoproterozoic) of North China. Both K-bentonite sequences occur in the same kind of black shale or slate successions and show similar facies changes in ascending order. This is in good agreement with Ettensohn's lithospheric-flexure models of supracrustal loading, caused by the plate-margin subduction and collision. Geochemical analyses show that the parent magmas of the two K-bentonite sequences from widely separated geological eras, originated in similar syn-collision and volcanic arc tectonic settings, which produced mainly an intermediate-to-felsic series of trachyandesitic, rhyodacitic/dacitic, and rhyolitic magmas. This type of volcanism is associated with the collision and subduction of paleo-continental blocks/arcs. The large ash-falls of the peri-Iapetus Orogeny support the tectonic settings of this volcanism. Compared with the K-bentonites and the black-shale successions of the Wufeng and Longmaxi formations of South China, which are related to the accretion of the Cathaysia Block to the Yangtze Block during the Ordovician-Silurian transition, the Neoproterozoic K-bentonites and dark shale/slate deposition of the Xiamaling formation in North China probably reflect similar plate-tectonic movements. The Neoproterozoic succession of K-bentonites and black shales suggests that a similar accretionary process was active around the North China Block at this time. Consequently, with reference to the previously reported dating of this formation at about 1 000-850 Ma, it is likely that the K-bentonites and the dark shales/slates of the Neoproterozoic Xiamaling formation were probably volcanic and depositional responses that reflect accretion related to the North China Block during the assembly of the supercontinent, Rodinia or Pangea 850 Ma. |
| Keywords: | K-bentonite black/dark shale accretion processes Early Paleozoic Neoproterozoic S and N China |
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