Y.N.Gorozhanina The sedimentary response of the arc –continent collision i n the South Urals

1. Y.N.Gorozhanina The sedimentary response of the arc –continent collision in the South Urals The stratigraphy and facies of the Uralian foreland thrust and fold belt

27. Conclusion • In conclusion it can be said that the microfacial analysis of the syntectonic sedimentary sequences provides a good help in the restoring of the geological history of the Uralian fold and thrust belt. • According to sandstone composition in the Famennian during the arc-continent collision the accretionary complex , in particular the backstop damage zone containing ultramafic rocks along MUF and metamorphic complexes to the west from it contributed most of the detritus to the syncollisional Zilair Fm. • In the Carboniferous some pause in tectonic activity was reflected in the accumulation of deep water limestones with shale and cherts. The activation of collision process reflects in the style of deformations and in the composition of the Middle-Upper Carboniferous rocks. The Bashkirian sandstones consist of the mixture of coeval and non-coeval carbonate clasts both intrabasinal and extrabasinal, and extrabasinal siliciclasts, the latter is the same as in the Zilair Fm. That means that during the Bashkirian the accretionary compex formed an uplift due to activation of collision process and formation of the fold and trust belt. Some siliciclasts can be recycled from the eroded Zilair rocks. • The carbonate clasts are the main component in the sandstones from the Carboniferous time. The mixing of the siliciclasts and non-coeval carbonate clasts could be the result of the erosion of the uplifted thrust stacks inside the basin. The contemporaneous bioclasts can come both from the western shelf slope and the eastern uplifts. The intercalation of sandy packstones and calcarenites could be due to interfingering of the material from different sources.