Re-understanding of the Ordovician geographical division in China
The continental crust in China consists of the North China,Yangtze and Tarim cratons,along with several micro-continents and orogenic belts surrounding them.Based on their characteristics,this paper presents development of these geological terranes in China during the Ordovician period based on four types:cratons,micro-continents in oceanic plates,orogenic belts,and uncertain terranes.Addi-tionally,by integrating paleogeographic data,a new perspective on the Ordovician geographical division in China is proposed,encompassing sixteen regions within four mega-regions.During the Ordovician,cra-tons and micro-continents in China were primarily distributed in the peri-Siberian area,the Paleo-Asian Ocean,the Proto-Tethys Ocean and the northern margin of Gondwana,and the four mega-regions were in alignment with these distributions.The North China and Tarim cratons belong to the Proto-Tethys Ocean Mega-region,despite separating the Paleo-Asian and the Proto-Tethys oceans.The North Xinjiang and Xing'an regions are located within the peri-Siberian Mega-region.The former comprises the Altay,Jung-gar-Tuha micro-continents,and the East and West Junggar orogenic belts,whereas the latter encompasses the Northeast China micro-continental group of Erguna,Xing'an,Xilinhot,Songliao,and Jiamusi.The Central Tianshan-Beishan Region pertains to the Paleo-Asian Ocean Mega-region,and the Yining micro-continent is a member of this region.Except the North China and Tarim regions,the Proto-Tethys Ocean Mega-region includes the Qaidam-Qilian,Kunlun-Qinling,Yangtze,Cathayasia,Indo-China,and Songpan-Ganzi regions.Among them,the middle-Altun and Quanji micro-continents belong to the Qai-dam-Qilian Region,and the Yidun micro-continent belongs to the Songpan-Ganzi Region.The Qangtang,Lhasa,Himalaya,Sibumasu and Hainan regions were separated from the Gondwana Mega-region,with the Baoshan and Lincang micro-continents being part of the Sibumasu Region.The Alexa and Dunhuang terranes are included in the North China Region and the Tarim Region,respectively.There is a great difference between the above understanding of the geographical division of Ordovician period in China and that of the predecessors.The author aims to draw more scholars'attention and explore a more reasonable di-vision scheme.
万方数据
维普
