华北克拉通早元古代拼合与Columbia超大陆形成研究进展

Paleoproterozoic amalgamation of the North China Craton and the assembly of the Columbia supercontinent

通过对华北克拉通及全球其他古老大陆及其早元古代碰撞造山带的系统对比,提出了地球上20~18亿年碰撞型造山带记录了一次全球性大陆拼合事件,并导致一个早-中元古代超级大陆的形成,该超级大陆称为Columbia或Nuna.华北克拉通两条古老的喜马拉雅型碰撞造山带（即~19.5亿年的西部孔兹岩带和~18.5亿年的中部造山带）的发现,证实了华北克拉通基底是~19.5亿年和~18.5亿年期间多个微陆块拼合而成,完整保留了Columbia超大陆的聚合记录,说明华北克拉通是Columbia超大陆的组成部分之一.

Throughout the 1990＇s, the plate reconstruction of the Supercontinent Rodinia was the major field of supercontinental reconstruction, and became a hot research topic in the international community. However, in the course of the Supercontinent Rodinia reconstruction, we found three aspects are inconsistent with the idea that the Supercontinent Rodinia is the first supercontinent in the Earth geological history：（1） Between many continental blocks in the Supercontinent Rodinia such as between North America and Siberia, North America and Antarctica, North America and Australia, South America and the Baltic, West Africa and South America and so on, is not assembled by the Grenville-period orogenic belts of about 1 Ga, indicating that these continental blocks had merged together before the formation of the Rodinia;（2） All the large blocks within the Rodinia contained older continental collision orogenic belts of 2.1–1.8 Ga than the Grenville orogenic belt;（3） During the 1.8–1.1 Ga（700 Ma）, the Earth had basically no large-scale continental collisional events. On the contrary, the global collisional orogenic events of 2.1–1.8 Ga on the Earth resulted in 2.1–1.8 Ga of orogenic belts＇ distribution between the old continents and in their internals are global, such as 2.1–2.0 Ga Transamazonian-Eburnean collision zone between the South America and West Africa Continental blocks, 1.9–1.8 Ga Trans-Hudson collision zone in the North America continental block, the Nagssugtoquidian collisional zone of 1.9–1.8 Ga within the Greenland continental block, the Kola-Karelia collision zone of 1.9–1.8 Ga within the Baltica continental block, the Akitkan collision zone within the Siberia Block, 2.0–1.9 Ga Limpopo collisional zone between South African Kaapvaal and Zimbabwe blocks, 2.0–1.9 Ga Capricorn collision zone between the West Australian Yilgarn and Pilbara cratons, 1.850 Ga Trans-North China Orogen in the Central North China Craton and others. Therefore, based on the mentioned-above, Zhao et al.（1998） first proposed in the 15 th Australian Geological Congress that these widely-distributed 2.1–1.8 Ga collision zones in the Earth may record a global continent-continent collision event, resulting in the formation of one pre-Rodinia supercontinent. The supercontinent named the ＂Hudson＂ because the Trans-Hudson orogenic belt in the North American Continent is the result of the most typical continentcontinent collision zone. By a systematic comparison of Paleoproterozoic collisional orogenic belts in the North China Craton and the other ancient continents all over the world, we finally proposed that the 2.0–1.8 Ga collision-type orogenic belts in the Earth recorded a global continental collision event, resulting in the formation of the Meso-Paleoproterozoic supercontinent lately named as Columbia or Nuna. The discovery of two ancient Himalayan-type collisional orogenic belts, i.e. the ~1.95 Ga Khondalite Belt in the western part and the ~1.85 Ga Trans-North China Orogen in the central of the North China Craton confirmed that the basement of the North China Craton resulted from the amalgamation of several microcontinental blocks in ~1.95 Ga and ~1.85 Ga, completely recording assembly of the Columbia supercontinent. Therefore, the North China Craton is one part of Columbia supercontinent.