Paleomagnetic constraint on the movement of the Indochina Block since Late Paleozoic:Progress and prospect
To reconstruct the movement history of continental blocks is crucial for understanding the Earth's system evolution and its dynamic mechanism.The amalgamation of the East Asian blocks is characterized by the closure of the Paleo-Asian Ocean and Tethyan oceans,as a part of the assembly of the Pangea Supercontinent.The Indochina Block is one of the main continental blocks/terranes in East Asia,and it is believed to have rifted and drifted from the northern margin of Gondwana since the Late Paleozoic.Its northward movement and collision with the Eurasia mainland have been paleomagnetically reconstructed over these years.The newly obtained paleomagnetic data from the Indochina Block are thoroughly summarized and analyzed,depicting a step-wisely drifting history of the Indochina Block from the South to the North hemisphere since the Late Paleozoic.It was located at the mid-low latitude area in the South hemisphere during late Carboniferous to middle Permian,which is consistent with the warm-water bio-fossils and fossil-rich limestone;it drifted across the Paleo-equator during the Late Permian and collided with the mainland Eurasia at ca.30°N by early Late Triassic.The Indochina-mainland Eurasia convergence rate reached a peak at late Permian to early Triassic,indicating an acceleration of the Paleo-Tethys Ocean subduction.This agrees well with the peak age of the subduction-related magmatic rocks that erupted at the Jinshajiang-Ailaoshan suture and Changning-Menglian suture.Interestingly,the well-constrained drifting history of Indochina is coincident with that of the North Qiangtang,suggesting a synchronous northward movement process and indicating a close paleogeographic affinity during at least early Permian to Late Triassic.In contrast,the South Qiangtang and the Sibumasu blocks show markedly different rifting-drifting history.This distinct history is reflected in the Longmu Co-Shuanghu-Changning-Menglian suture belt,which represents a major branch of the Paleo-Tethys Ocean.The closure of the Paleo-Tethys Ocean branches,as well as the amalgamation of the Gondwana-derived blocks with Eurasia likely influenced the evolution of the Paleo-Asian Ocean.The sequential amalgamations of Mongolian blocks/terranes,North China,South China,as well as the North Qiangtang-Indochina and South Qiangtang-Sibumasu,to the mainland Eurasia,probably represent an important part of the assembly of the Pangea Supercontinent.In the Mesozoic,the Indochina Block,as part of the Eurasia,recorded the Jurassic true polar wander,which moved it from ca.30°N to ca.20°N.This latitudinal movement is still noticeable in the Late Cretaceous to early Cenozoic,which is probably caused by the subduction of the Neo-Tethys.This paper summarizes and analyzes newly obtained paleomagnetic data from the Indochina Block.Despite ongoing challenges in understanding certain aspects,our analysis successfully reveals the drifting history of the Gondwana-derived blocks/terranes.Notably,the amalgamation of these Eastern Asian blocks/terranes played a significant role in the assembly of the Pangea Supercontinent.
Indochinapaleomagnetismreconstruction of paleogeographypaleo-tethysPaleozoicMesozoic
闫永刚、黄宝春、张培震、赵杰、张东海、贾舒斐、张逸鹏、薛艺
展开 >
中山大学地球科学与工程学院,珠海 519080
南方海洋科学与工程广东省实验室(珠海),珠海 519080
北京大学地球与空间科学学院,北京 100871
长安大学地球科学与资源学院,西安 710016
西北大学地质学系,西安 710069
Centre for Planetary Habitability(PHAB),University of Oslo,NO-0316 Oslo,Norway
NETL
NSTL
万方数据
