PALEOZOIC TECTONIC EVOLUTION OF THE NORTHERN MARGIN OF THE NORTH CHINA CRATON AND ITS ADJACENT CENTRAL ASIAN OROGENIC BELT: A REVIEW

The Central Asian orogenic belt is located between the Siberian, North China, and Tarim cratons and has been regarded as the world’s largest site of juvenile crust formation in the Phanerozoic，mainly in Paleozoic. To understand this process reconstruction of Gondwana and craton continents globally in early Cambrian can lead to recognize a huge paleo-ocean between the Siberian and North China continents. Most Precambrian micro-continents in the Central Asian orogenic belt have a tectonic affinity to the Tarim or Yangtze cratons. Deformation and high-grade metamorphism in Precambrian micro-continent nearby Gobi Altai, Mongolia occurred at 840±8 Ma. The bottom volcanic rocks of the cover sequence yielded zircon U-Pb age at 777±6 Ma. The sequence from upper Neoproterozoic to Cambrian can be correlated to that of Tarim, Yangzi, Kazakhstan and worldwide, which suggest that subduction of the paleo-ocean is greater than that in early Cambrian. The accretionary juvenile crust in the Central Asian orogenic belt could be a normal case. The Bainaimiao arc belt, one of the most important early Paleozoic arc systems south to the Solonker suture zone, was active from 520 Ma to 420 Ma and can extend to east Siping in NE China. Zircon U-Pb geochronological results of metasedimentary rocks in the Bainaimiao arc belt indicate that they are early Paleozoic in age, not Precambrian as previously regarded. It was separated by a wide ocean from the North China craton during the Cambrian–Ordovician period. Successive northward subduction resulted in contraction of the ocean and final accretion of the Bainaimiao arc to the northern North China craton during the Late Silurian–earliest Devonian by arc-continent collision. Arc-continent collision could be an important mechanism for continental crustal growth and formation of the huge Central Asian orogenic belt. Recent identification of extensive volcanism from Carboniferous to Early Permian in northern North China craton and deformation as well as uplift in the Inner Mongolia Paleo-Uplift, northern margin of the North China craton in early Mesozoic clarify further the Andes-style continental margin in late Paleozoic.