**9. Conclusions**

The anomalous concentrations of fresh olivine, pyroxene, and ultrabasic/basic rock fragments grains in the Kolosh sandstones were derived from wide varieties of ultrabasic/basic intrusive and extrusive igneous rocks of pre-tertiary ophiolites from Zagros thrust zone. Olivine/pyroxene-rich sandstones of the Kolosh formation are important to study the regional correlation of the ophiolite's composition and the differences along the Neotethyan ophiolite belts of the Neotethys ocean.

Olivine and pyroxene grains were derived from varieties of rocks, such as tectonite peridotite, pyroxenite, lherzolite, heirzburgite, basalt, and dolerites, basically derived from Rayat and Hasan Beg ophiolites, the nearest to Badelyan study area. The radiolarian chert and carbonate formations with ophiolite rocks in Rayat, Choman, Galalah, and Hasan beg are suggested as sources of chert and carbonate rock fragments in the Kolosh sandstones.

The fresh olivine and pyroxenes grains are the products of subaerial and submarine erosion of the thrusted mantle and oceanic crust sheets. Intense wave action accelerated erosion on the beach and concentrate the heavy olivine and pyroxene grains, which were slumped to a deeper trench basin by the tectonically-induced turbidity currents.

Facies analysis and related sedimentary structures suggest progressive development in the Kolosh basin starting from slope marine margin in the lower part up to the basin plain in the upper part of the formation passing through the submarine fan environment.

The Neotethys foreland basin is tectonically controlled by thrusting and the Kolosh sediments are deposited in progressively deepening upward setting. According to the field observations, facies and associations and stratigraphic successions suggest four stages of tectonosedimentry development, these are slope channel, inner fan, outer fan, and hemipelagic/pelagic apron. These stages are controlled directly by tectonism and seismicity created by continuous thrusting.
