【作者】 朱彦虎；

【导师】 孙东怀；

【作者基本信息】 兰州大学 ， 自然地理学， 2008， 硕士

【摘要】 通过系统的野外地质调查,在塔里木盆地中西部选择了地层连续稳定、从浅海相(泻湖)到内陆河湖相再到风成相都出露良好的晚新生代塔格山剖面进行了野外地层测量、岩性描述及样品采集。通过系统的粒度、磁化率和化学成分等古气候变化代用指标的测量,并结合古地磁极性年代研究,获得了各项气候变化代用指标的时间序列和剖面深度序列;以岩性变化为主导,结合各项古环境记录,讨论了塔里木盆地自4.2Ma海退以后的演化过程及干旱化历史,在此基础上进一步探讨了青藏高原隆升与塔里木盆地干旱化演化的关系,以及新构造运动对全球气候变化的影响。本论文得出以下主要结论:1.塔里木盆地中西部经历三个阶段的沉积历史:浅湖相(4.2Ma-3.4Ma)、风成湖相(3.4Ma-3.0Ma),冲积洪积相(3.0Ma-0.8Ma)。2.风成组分粒径3.4Ma(620米)突然增大,可能指示塔里木盆地的干旱化加剧,水成组分3.0Ma(460米)的突然增大,可能指示塔里木盆地风成湖相向冲洪积相演化的转折。3.Zr/Sr3.0Ma(460米)的峰值,可能指示3.0Ma附近降水量较多,对照泥岩、风成沙互层的岩性变化,推断3.0Ma左右可能是塔格山记录中塔里木盆地干期最干、湿润期降水量最多的阶段。4.塔格山形成的年代可能在0.6-0.8Ma之间。5.发现了大约从3.4Ma开始,塔里木盆地开始干旱化,直到1.1Ma塔里木盆地基本处于干旱半干旱交替出现,1.1Ma以后,现代塔克拉玛干沙漠的雏形形成。更多还原

【Abstract】 On a systematic geological survey,Mazatagh section,a consecutive and well-outercropping section of Cenozoic in central Tarim basin,was chose for investigation on stratigraphy,paleomagnetism and paleoclimatology.Meanwhile,the time scales of paleoclimate records were reconstructed on the systematic measurement of grainsize,magnetic susceptibility and element,combining with the magnetostratigraphy of the section.On that basis,we get some understanding about the relationship between the drought history of Tarim basin and the uplift of Qinghai-Tibet Plateau in Cenozoic. The following points mark the main conclusions of this thesis:1.Tarim basin had experienced a sedimental history of shallow lake(4.2Ma-3.4Ma), aeolian-lake(3.4Ma-3.0Ma),and alluvial plain(3.0Ma-0.8Ma).2.The mean size of aeolian component increased quickly at the age of 3.4Ma(620m) may suggest a intense aridity in Tarim basin,then the mean size of aqueous component increased quickly at 3.0Ma(460m)may suggest that sediment environment had changed from aeolian-lake to alluvial plain.3.Zr/Sr reached its peak at 3.0Ma(460m),it may suggests that there was more precipitation at 3.0Ma by contrast with aeolian accumulation in large scale in the stratum.4.The Mazatagh range uplift at 0.8Ma.5.The aridity in Tarim basin started at 3.4Ma,there had been a arid-semiarid environment in Tarim basin from 3.4Ma-1.1Ma,the rudiment of modern Taklimakan Desert appeared at 1.1Ma.更多还原