摘要
通过对磷灰石裂变径迹(AFT)数据系统的对比,本文从整体上分析了中、上扬子区块各地质单元在晚中生代、新生带抬升冷却特征,并初步构建了区域上中-新生代构造活动与内陆变形的时空关系.它们的构造活动在空间上具有分区性和连续性特征,在时间上具有幕式性特征.空间上的分区性与连续性主要表现在各地质单元隆升特征的差异性,即中扬子北缘江汉盆地、黄陵隆起最早开始冷却到大巴山逆冲带、米仓山-汉南隆起晚侏罗世自北(东)向南(西)的隆升与江南-雪峰山隆起、湘鄂西褶皱带、川东褶皱带及川东北地区自南东向北西依次递进逆冲褶皱变形的差异;构造活动时间上的幕式特征主要表现在阶段性的快速冷却及其相间的缓慢冷却过程.中、上扬子北缘大巴山逆冲带、米仓山-汉南隆起磷灰石裂变径迹年龄从北(东)向南(西)逐渐变小,它们在晚中生代、新生代处于秦岭-大别造山带向扬子地块逆冲挤压变形的动力学背景;而湘鄂西褶皱带、川东褶皱带及川东北地区磷灰石裂变径迹年龄自南东向北西方向减小的趋势主要受控于太平洋板块的俯冲挤压效应.中、上扬子喜山晚期的快速冷却主要是青藏高原隆升及其向东与南东方向构造逃逸挤压作用及亚洲季风等气候变化的响应.磷灰石裂变径迹的系统分析为中、上扬子递进扩展构造变形提供了年代学约束.
A total of 60 new apatite fission track （AFT） data from Middle-Upper Yangtze block provide a database to evaluate the Late Mesozoic and Cenozoic denudation and cooling history of Middle-Upper Yangtze block on a regional scale; combined with the previous published AFT data, the temporal-spatial correlation tectonic activities and intra-continental history among each part is regionalized is p def and reliminarily constructed between regional Cenozoic ormation. The difference in denudation or cooling successive in space, and is episodic in time. It wasfirst deformed and folded in Jianghan bansin and Huangling uplift, and then the onset timing of formation becomes later from N（E） to S（W） in Micasngshan and Dabashan, while others become later from southeast to northwest, including Xiangexi, east and northeast Sichuan basin, which stands for the characteristics of spatial variation. Episodic characteristics of tectonic movement in time are mainly shown as alternative rapid cooling processes and slow cooling processes. The age of the AFT from different geological units in Micang shan and Daba shan becomes smaller from N（E） to S（W）, which means that it was controlled by the thrusting compression of Qinling- Dabie orogen in Late Mesozoic and Cenozoic; while the age of the AFT from Xiang＇exi, east and northeast Sichuan basin becomes smaller from southeast to northwest, standing for the far-field effect of subduction of Pacific plate. The rapid exhumation and cooling event in Late Cenozoic was atributed to uplifting and the northeastward growth of the Tibetan Plateau and onset of theprogressive expansion tectonic deformation of the Middle-Upper Yangtze block.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第8期2608-2619,共12页
Chinese Journal of Geophysics
基金
中石化海相前瞻性课题(YPH08057)资助
关键词
扬子地块
裂变径迹
抬升剥蚀
青藏高原
晚中生代-新生代
Yangtze block
Fission track
Uplift and denudation
Tibetan Plateau
Late Mesozoicand Cenozoic
