ABSTRACT
On the global structure-tectonic schemes of occurrence of ophiolite associations, the mafic-ultramafic massifs in them form a system of differently directed belts of varying lengths (Fig. 13.1). Part of this system is hundreds of mafic-ultramafic massifs which are concentrated along the Asian shore of the Pacific from Chukchi Peninsula to Southeast Asia (Fig. 13.2). These massifs are structurally confined to the zones of long-lived deep faults which were the channels of repeated penetration of basaltoid melts and tectonic blocks of ultramafic restites from the upper mantle to the Earth’s crust. It was established that the deep fault zones, or sutures, have mainly steep slopes, but, as a result of repeated folded-block deformations, on some sites these acquired relatively gentle slopes. Some researchers think that the mafic-ultramafic massifs confined to gently inclined fault zones took part in the formation of overlapped structures (overthrusts).
