塔里木古海湾新生代海退时限及方式的初步探讨  

A Tentative Discussion on the Time and the Way of Marine Regression from Tarim Bay during the Cenozoic

作　　者：张华[1] 刘成林[1] 曹养同[1] 孙宏伟[2] 王立成[1] 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [2]中国地质大学(北京),北京100083

出　　处：《地球学报》2013年第5期577-584,共8页Acta Geoscientica Sinica

基　　金：国家"973"计划项目(编号:2011CB403000);"十二五"国家科技支撑计划(编号:2011BAB06B00)联合资助

摘　　要：对库车盆地新生代84个石膏或硬石膏进行硫同位素分析,用以划分该时期内海侵—海退旋回以及最终海退时限的标定。石膏δ34S值演化特征显示,库车盆地新生代经历了两次明显的海侵,其分别为古新世中期和始新世中后期。库车盆地新生代最终海退时限与西部塔里木海湾在天山山前带的退缩时限相一致,表明至少在渐新世中晚期塔里木海湾才完全消失。通过区域对比,本文将新生代塔里木海湾的海退时限和方式概括为:①始新世早期塔里木海湾在昆仑山前带的西段最先发生海退;②之后,海退向昆仑山东段开始迁移,至始新世晚期海退延伸至盖孜、阿尔塔什等地;③最终,海退由南向北迁移至天山一带,至渐新世末期特提斯海水完全退出塔里木地区。塔里木盆地新生代海退时限、方式进一步指示了印度—亚洲大陆碰撞所产生的构造作用具有明显的距离效应;塔里木海湾新生代不同地区在海退时限上的不同步性说明,塔里木盆地新生代海侵—海退旋回不是单一地受全球海平面升降的控制,而是全球海平面变化以及区域构造活动等多种因素共同作用的结果。The sulfur isotope of eighty-four gypsums or anhydrites was used to mark the transgression-regression cycle and the time of final marine regression from Kuqa Basin during Cenozoic. δ34S curve indicates that there exist two obvious transgression in Middle Paleocene and Middle–Late Eocene, respectively. The final marine regression from Kuqa Basin occurred at the end of Oligocene, which was time-equivalent with the regression from southwest Tarim in Tianshan area, indicating that the retreat of the sea water from Tarim Bay lasted until the end of Oligocene. Based on the regional contrasting study in this paper, the authors sum up the time and the style of the marine regression from Cenozoic Tarim Bay as follows： ① the initial retreat occurred at the beginning of Eocene to the west foot of the Kunlun Mountains; ② then the retreat moved to Kezi and Aertashi areas at the east foot of the Kunlun Mountains in late Eocene; ③ finally, the retreat migrated to the Tianshan Mountains at the end of Oligocene, which also represents the thorough marine regression from Tarim Bay. This way of marine regression from Tarim further implies that there existed a distant effect caused by India-Asia collision, and the asynchronism of marine regression among different areas in Tarim Basin shows that the transgression-regression cycle of Tarim Bay in Cenzoic was not only controlled by global sea level eustasy but also by some other factors such as regional tectonism.

关 键 词：塔里木海湾 硫同位素 海退时限 区域对比 新生代 

分 类 号：P534.61[天文地球—古生物学与地层学] P597.2[天文地球—地质学]