Paleomagnetic constraints on the tectonic history of the major blocks of China duing the Phanerozoi

来源 :Science in China(Series D:Earth Sciences) | 被引量 : 0次 | 上传用户:yan1982zi
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Paleomagnetic study of China and its constraints on Asia tectonics has been a hot spot. Some new paleomagnetic data from three major blocks of China, North China Block (NCB), Yangtze Block (YZB) and Tarim Block (TRM) are first reported, and then available published Phanerozoic paleomagnetic poles from these blocks with the goal of placing constraints on the drift history and paleocontinental reconstruction are critically reviewed. It was found that all three major blocks were located at the mid low latitude in the Southern Hemisphere during the Early Paleozoic. The NCB was probably independent in terms of dynamics, its drift history was dominant by latitudinal placement accompanying rotation in the Early Paleozoic. The YZB was close to Gondwanaland in Cambrian, and separated from Gondwanaland during the Late Middle Ordovician. The TRM was part of Gondwanaland, and might be close to the YZB and Australia in the Early Paleozoic. Paleomagnetic data show that the TRM was separated from Gondwanaland during the Late Middle Ordovician, and then drifted northward. The TRM was sutured to Siberia and Kazakstan blocks during the Permian, however, the composite Mongolia NCB block did not collide with Siberia till Late Jurassic. During Late Permian to Late Triassic, the NCB and YZB were characterized by northern latitudinal placement and rotation on the pivot in the Dabie area. The NCB and YZB collided first in the eastern part where they were located at northern latitude of about 6°_8°, and a triangular oceanic basin remained in the Late Permian. The suturing zone was located at northern latitude of 25° where the two blocks collided at the western part in the Late Triassic. The collision between the two blocks propagated westward after the YZB rotated about 70° relative to the NCB during the Late Permian to Middle Jurassic. Then two blocks were northward drifting (about 5°) together with relative rotating and crust shortening. It was such scissors like collision procedure that produced intensive compression in the eastern part of suturing zone between the NCB and YZB, in which continental crust subducted into the upper mantle in the Late Permian, and then the ultrahigh pressure rocks extruded in the Late Triassic. Paleomagnetic data also indicate that three major blocks have been together clockwise rotating about 20° relative to present day rotation axis since the Late Jurassic. It was proposed that Lahsa Block and India subcontinent successively northward subducted and collided with Eurasia or collision between Pacific/Philippines plates and Eurasia might be responsible for this clockwise rotating of Chinese continent. Paleomagnetic study of China and its constraints on Asia tectonics has been a hot spot. Some new paleomagnetic data from three major blocks of China, North China Block (NCB), Yangtze Block (YZB) and Tarim Block (TRM) are first reported, and then available published Phanerozoic paleomagnetic poles from these blocks with the goal of placing constraints on the drift history and paleocontinental reconstruction are critically reviewed. The was three all major blocks were located at the mid low latitude in the Southern Hemisphere during the Early Paleozoic. The NCB was probably independent in terms of dynamics, its drift history was dominant by latitudinal placement accompanying rotation in the Early Paleozoic. The YZB was close to Gondwanaland in Cambrian, and separated from Gondwanaland during the Late Middle Ordovician. The TRM was part of Gondwanaland , and might be close to the YZB and Australia in the Early Paleozoic. Paleomagnetic data show that the TRM was separated from G ondwanaland during the Late Middle Ordovician, and then drifted northward. The TRM was sutured to Siberia and Kazakstan blocks during the Permian, however, the composite Mongolia NCB block did not collide with Siberia till Late Jurassic. During Late Permian to Late Triassic, the NCB and YZB were characterized by northern latitudinal placement and rotation on the pivot in the Dabie area. The NCB and YZB collided first in the eastern part where they were located at northern latitude of about 6 ° _ 8 °, and a triangular oceanic basin in the Late Permian. The suturing zone was located at northern latitude of 25 ° where the two blocks collided at the western part in the Late Triassic. The collision between the two blocks propagated westward after the YZB rotated about 70 ° relative to the NCB during the Late Permian to Middle Jurassic. Then two blocks were northward drifting (about 5 °) together with relative rotating and crust shortening. It was such scissors like collision pro cedure that produced intensive compression in the eastern part of suturing zone between the NCB and YZB, in which continental crust subducted into the upper mantle in the Late Permian, and the the ultrahigh pressure rocks extruded in the Late Triassic. Paleomagnetic data also indicate that three major blocks have been together clockwise rotating about 20 ° relative to present day rotation axis since the Late Jurassic. It was proposed that Lahsa Block and India subcontinent successfully northward subducted and collided with Eurasia or collision between Pacific / Philippines plates and Eurasia might be for for this clockwise rotating of Chinese continent.
其他文献
寒冷地带使用的汽车,冬季驾驶室内很冷,前窗玻璃结霜很厚,影响驾驶员的视野。而且,驾驶员手脚易冻坏,这就严重地影响了行驶的安全性。因此,很需要有可靠的暖风装置。目前,我
1.交流发电机在结构上采用了鸟咀形爪极。在更换激磁线圈时,得压下和压入软钢磁极。很多转子外园在装复后出现不园度,以致使用时出现电机“发摆”、发热及转子与定子相摩擦而
一、概述众所周知,汽车在行驶过程中情况是很复杂的,特别是在制动时车轮抱死的情况下,汽车就会向前滑移,发生交通事故的机会增多,制动稳定性不好、摆头甩尾等现象经常出现。
比较了甲基苯三唑与苯三唑的缓蚀性能,不同pH值条件下的缓蚀效率、热稳定性和抗氯性能。实验结果表明,甲基苯三唑比苯三唑具有更好的缓蚀性能、热稳定性和抗氯性能,可替代苯
旧的修复发电机轴承内外圈结合处磨损的方法有三种:焊锡法,电蚀法,冲坑法。以上三种方法虽然都能解决与轴承内外圈配合处的磨损和结合不牢的问题,但都有一定的缺点,不但修复
四、燃料供给系燃料供给系的任务就是保证供给汽油机工作时所需要的可燃混合气,由油箱、油开关、油管和化油器组成.在汽油机上装设化油器,可将汽油雾化成细小的油滴,使单位
西欧最大的陆上油田Wytch Farm位于英格兰南海岸一个环境十分敏感的海滨地区,七十年代末,该油田的早期开发区域主要集中在整个油藏的陆上部分。从1989年就开始选择适合于该油
我厂在1980年10月大修的116台汽车中,消耗曲轴43只,价值98900元。可见,为降低修车成本,必须减少曲轴消耗量。而延长曲轴使用期限是减少曲轴消耗量、降低修车成本的重要措施
两位瑞典青年工程师发明了一种塑料自行车,通体由塑料构成,只有轮胎是橡胶的。每个车轮仅有8根轮辐,跟早期的自行车相似。这种自行车十分轻便。坐垫和把手颇柔软,不会生锈;
自1973年以来,由于对废气公害的限制日益严格,相应地对点火系的点火特性也提出了更高的要求。迄今为止,几乎大部分汽车都是采用克塔里格式点火装置,它是通过断电器的触点开闭