facies analysis, sedimentation conditions and geochemistry of clastic deposits of ashin formation (late ladinian-early carnian), northeast of nain, east of central iran

The present study aims to investigate the petrographic, geochemical features, and depositional facies of the late triassic ashinformation (nakhlak group, central iran). for this purpose, 100 thin sections, and 13 samples of fine-grained sedimentary rocks wereanalyzed for their petrographic and geochemical characteristics, taken from a 330-m thick section of this formation. the petrographictypes identified in this formation include sandstone, siltstone and limestone. this study suggests limestone facies are deposited in upperparts of the distal submarine fan towards the shore, sandstone facies are deposited in the middle part of the distal submarine fan, andthe shale facies are deposited in lower parts of the distal submarine fan towards the abyssal plain by turbidity currents. the plotting ofpetrographic data on ternary diagrams for compositional classification illustrate their composition as litharenites, sub-litharenites, anda few litharenite-feldspathic and shales. discrete diagrams refer to a tectonic setting of a continental arc complex and the activecontinental margin. the results of the modal analysis and geochemical data indicate the orogenic re-cycling for these deposits. ciaand ciw indexes indicate moderate weathering of the source area under semi-arid to semi-humid climates.