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Detail description of texture and composition of 880 samples from Upper Red Formation sandstones in central part of its basin directed to identification of major petrofacies. On this basis, 17 petrofacies in the south and 16 petrofacies in the north successions were distinguished and described comprehensively. Major components variation of petrofacies through measured sections is used for analysis of source region and diagenetic history. A distinct diversity in the source rocks composition is indicated from component variation analysis. Major characteristic of the petrofacies and detrital mode analysis of sandstones indicate deposition in a back arc setting in which block faulting controlled accommodation development. Active tectonic setting of the basin is responsible for textural properties of the petrofacies. Composition of the petrofacies and its variation through measured sections was mainly controlled by source rocks characteristics. Diagenetic features of the petrofacies are significant enough to necessitate thorough diagenetic study prior to and depositional and/or provenance investigation.