The North Asian craton may be isolated from other Precambrian structural units of northern Asia. These include the Precambrian Siberian platform pericratonal geosynclinal systems of the western and southern margins of the Siberian platform and the Verkhoyansk-Chukchi epicratonal geosynclinal region. A common feature of these regions is the presence of continuous and gently dislocated crystalline basement formed by the oldest Precambrian complexes (older than 3.3-3.5 b.y.), by gneiss complexes 2.5-2.6 b.y. old, and by volcanogenic-schist complexes 1.6 b.y. old. The Upper Precambrian beds of the Siberian platform are thin (less than 2 km) terrigenous-carbonate complexes, whose formation began north and east of the platform about 1.6 b.y. ago, south and west of the platform bout 1.0 b.y. ago, and in the central areas about 0.7-0.65 b.y. ago. The upper Precambrian rocks of pericratonic and epicratonic geosynclinal systems are represented also by the nonmagmatic carbonate-terrigenous complexes of greater thickness than the platform rock sequences.

Analyses of the Precambrian sections of Severnaya Zemlya and Wrangel Island and geophysical data confirm that the North Asian craton extends from the adjacent shelf region of the Arctic Ocean to the continental slope.

On the west, south, and southeast the North Asian craton is separated from the central Asian fold belt by deep fault zones with Precambrian intrusions of hyperbasites and gabbroids. The central Asian fold belt is characterized by complex structure. Within its boundaries volcanogenic, terrigenous, and carbonate successions of upper Precambrian formations can be identified. Separation of the craton and the fold belt had occurred in early Precambrian time, 2.5-3.0 b.y. ago. The granitoid belt of Precambrian and Paleozoic ages and the zones of pronounced metamorphism (up to granulite and amphibolite facies) are confined to the boundary between the craton and fold belt.

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