摘要
本文通过分析准噶尔盆地南缘野外剖面、部分钻井岩心和天山内部野外剖面的碎屑重矿物及其组合特征,探讨了准噶尔盆地中-新生代物源体系和盆山格局的演化。准噶尔盆地南缘至少存在3个物源体系,各物源体系的重矿物组合、含量及其反映的物源属性均存在较大差异;其中,南部天山物源还存在东、西两部的差异。不同重矿物组合出现和不稳定重矿物的增加显示中-新生代存在3个构造活动相对活跃期,即晚侏罗世—早白垩世早期、晚白垩世和晚新生代。早-中侏罗世天山内部发育多个分隔的小型盆地,盆地南部边界至少位于后峡附近,不存在地理分隔明显的天山;晚侏罗世—早白垩世早期是天山隆升、盆山格局发生转变的时期,博格达山逐渐构成盆地南缘的又一重要物源;白垩纪—古近纪盆山格局变化不大,新近纪以来的强烈挤压构造背景使得天山山脉快速隆升,盆山格局发生重大改变。准噶尔盆地南缘中-新生代构造相对活跃期和盆山格局演变与欧亚板块南缘发生的构造事件具有良好的对应关系。
The analyses of heavy minerals and their assemblages were carried in practice for two field sections in the southern Junggar Basin, well cores data and two field sections in the inner Tianshan Mountains. Different heavy minerals＇ assemblages and increasing of unstable heavy minerals during Late Jurassic-earliest Cretaceous, Late Cretaceous and Late Cenozoic might indicate tectonic activity during these three periods. There existed three provenance systems in the southern Junggar Basin and several separated small basin within the Tianshan Mountains during Early-Middle Jurassic. The characteristics of sedimentary systems and heavy minerals proved that the Junggar and Tarim Basins were not physiographically separated by an ancestral version of the Tianshan Mountains during Early-Middle Jurassic. From Late Jurassic to the earliest Cretaceous, the distribution of Upper Jurassic Kalazha conglomerate and Cretaceous bottom conglomerate in front of the Bogda Mountains showed a tectonically active setting and obvious uplift of Tianshan during the latest Jurassic-earliest Cretaceous, and the Bogeda Mountains became another provenance system of the southern Junggar Basin, resulting in widely varied sedimentary successions between the Tarim Basin and the southern Junggar Basin. The basin-orogen pattern of the southern Junggar Basin didn＇t change greatly until the long-distance effect of India-Asia collision. The Mesozoic-Cenozoic tectonic activities and evolution of the basin-orogen pattern in the southern Junggar Basin should be related to the collision in the southern margin of the Eurasia plate.
出处
《地质科学》
CAS
CSCD
北大核心
2006年第4期648-662,共15页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家重点基础研究发展规划项目(2001CB409804)
中国石油集团中青年石油科技创新基金(05E7036)
中国博士后科学基金(2005037101)
"十五"国家重点科技攻关项目(2004BA616A-04)联合资助。
关键词
重矿物
天山造山带
盆山格局
准噶尔盆地南缘
中-新生代
Heavy minerals, The Tianshan orogen, Basin-orogen pattern, The southern Junggar Basin, Meso-Cenozoic
