塔里木板块与哥伦比亚超大陆的联系

Link Between Tarim Block and Supercontinent Columbia

塔里木拼贴时代和方式以及塔里木板块与哥伦比亚超大陆联系是塔里木板块形成演化中的关键问题,也是前寒武纪超大陆重建的重要问题,对塔里木盆地基底性质研究和油气勘探具有重要的理论意义和应用价值。本文首先通过南、北塔里木差异性对比分析和拼合时间的地质年代统计分析,探讨了形成统一的塔里木板块的时间问题。进一步基于大地构造比较学分析,将塔里木板块和扬子板块与世界其他板块的地质亲缘性开展综合对比分析,并结合古地磁数据分析和造山带及俯冲带对比分析,探讨了塔里木板块与哥伦比亚超大陆的关系。本文认为19~20亿年北塔里木向南塔里木俯冲并发生陆陆碰撞,形成了统一的塔里木板块。9~19亿年前塔里木板块、扬子板块与印度板块有较强的地质亲缘性,都处于哥伦比亚超大陆的西部边缘,并在地块周缘存在俯冲带,与北美板块东南缘的俯冲带具一定的可对比性;而华北板块与西伯利亚板块、波罗的板块亲缘性较强,位于古赤道附近,处于哥伦比亚超大陆的东部边缘。构造热事件的地质亲缘性表明塔里木、扬子和华北克拉通都是哥伦比亚超大陆周缘的小型克拉通,共同参与了哥伦比亚超大陆的汇聚过程。

The time and mode of the Tarim assembly and the link between the Tarim block and the supercontinent Columbia are key issues in the formation and evolution of the Tarim block as well as the reconstruction of the Precambrian supercontinent.They are of great theoretical and application value to the basement properties and oil and gas exploration in the Tarim Basin.The contrast between the northern Tarim and southern Tarim and the time of integration of the two counterparts are discussed based on statistical analysis of the dating results.Based on the geological relationship among the Tarim block,the Yangtze block and the other blocks in the world,the link between the Tarim block and supercontinent Columbia is analyzed based on the comparison of tectonics,paleomagnetic data,orogenic belts and subduction zones.The Tarim block could be united by the collision while the North Tarim subducting beneath the South Tarim at 1.9-2.0 Ga.During the early Precambrian(1.9 to 0.9 Ga),the Tarim block,the Yangtze block and the Indian block had strong geological affinity.They were located in the western margin of the Columbia supercontinent,and there were subduction zones around the blocks,which were comparable with the subduction zone on the southeast margin of the North American block.The North China block,which is closely related to the Siberian block and the Baltic block,was located near the ancient equator and at the eastern edge of the Columbia supercontinent.The affiliation of thermo-tectonic events show that the Tarim,the Yangtze and the North China are small cratons around the margin of the supercontinent Columbia,all of which participated in the amalgmation of the supercontinent.