Abstract:

The area of central Asia is composed of three paleo-Plates: the Siberia, the Kazakhstan-Jungar and the Tarim. Each paleo-plate has its characteristic large fault system and each system, in turn, includes two sets of faults. The first set, which is of major importance runs parallel to the margin of the ancient continent, whereas the second set is always approximate per pendicular to the ancient continental margin. The internal features of every system exhibit much harmony during their evolution. These faults have evolved through two stages. The first stage, which is characterized by the formation of ophiolite or ophiotitic melange belts,corresponds to the disintegration of the continental crust. In contrast, the second stage coincides with the collision of paleo-plates. It is beyond doubt that the faults which were developed at the first stage have suffered intense reformation. It is concluded that the geometric relations between the large fault systems and the ancient continental margins are produced by an integration of continental disintegration and divergence, convergence and collision of moving plates. Significance of large fault systems also discussed in terms of the division of paleo-plates, the discrimination of their relative motion and the recovery of their primitive geometry.

Key words: large fault system, ancient continental margin, central Asia, paleo-plate division, relative motion of paleo-plates