Ophiolitic and related melanges / Офиолиты и связанный меланж

Geology has undergone a revolution during the last decade with the advent of the concept of global tectonics. It is becoming increasingly clearthat lateral movements of enormous plates, genesis of new crust at mid-ocean ridges, and subduction of that new crust to the mantle beneath the leading edge of an overriding plate are mechanismsthat cannot be extrapolated back into the earliest Precambrian (or Archean); quite different geotectonic mechanisms appear to have been operative then and immense oceans probably did not exist. Nevertheless, much of the modern geologist's preoccupation is with the search for fossil plate boundaries in Phanerozoic systems. Ophiolites have been equated with such boundaries, though it is apparent that ophiolites can be developed in a wide variety of geotectonic zones at or near convergent plate margins. It is also possible that they can develop quite apart from such margins. The ophiolite problem is certainly more complex than was at first supposed. <...>