Qaidam Block

This block is a rhombic massif covering 120,000 km²that lies between the Qilian Mountains and the Kunlun Orogenic Belt. The block is mainly overlain by Cenozoic rocks. The outcrops in the north are early Proterozoic metamorphic rocks. The Nanhuan-Sinian System in this block is overlain by an unmetamorphosed moraine layer. In the early Palaeozoic, its northern margin was composed of stable carbonate deposits, and its southern border was composed of geo-synclinal clastic rocks mixed with neutral-basic volcanic rocks. Molasse formed and was widely distributed in the early Late Palaeozoic. The Carboniferous-Permian system is dominated by alternating marine-terrestrial facies. Inland basins developed during the Meso-Cenozoic Era. Intense folding took place in the late Cenozoic Era; and at this time, the northern and southern borders of this basin were deformed by basin-vergent thrust faults. These are typical characteristics of foreland basins. The Qaidam Block contains a wealth of...