A synthesis of the stratigraphic and tectonic setting of the Uralian ophiolites

The Ural Mountains mark a 2500km long, linear mid-Palaeozoic orogenic zone representing the closure of an ocean basin-island arc system between the European Plate to the west and the Siberian Plate to the east. Within the orogenic belt there are over 150 ophiolitic masses displaying sections of oceanic lithosphere with both harzburgitic and lherzolitic restites. These occur as tectonic slices and allochthons within volcano-sedimentary sequences and melanges. The paper concentrates on the main lines of evidence which form the basis for the palaeo-reconstruction of the collision zone. In particular it reviews the stratigraphic, sedimentological and structural evidence which is used to support a model in which the ophiolites were emplaced from the east onto the continental margin of the European Plate. In general the evidence is that as older oceanic crust was obducted, new arc and oceanic crust was being created to the east. As well as providing a general geological map which locates the major ophiolites, the paper presents cross sections across the major zones of the belt, showing current views on palaeo-reconstructions. A tectonic model is presented which attempts to integrate the volcanic-sedimentary history of the belt with the emplacement history of the ophiolites