Petrographic studies were carried out to explain the main variations in sedimentary facies and environment characteristics. Based on these studies, 16 microfacies were recognized for the Fahliyan strata, which were deposited in various segments of the ramp platform, including tidal-flat, lagoon, shoal, and open marine settings. Moreover, interpreted depositional environment and fauna components and sedimentary textures of microfacies were applied to identify three-order depositional sequences (sequences A to C). Sequence A, the lowest part of the Fahliyan strata, comprises sedimentary facies related to shoal and open marine settings. Sequence B constitutes the middle part of the formation, and the open marine segment was considered the primary depositional environment for most of the recognized microfacies in this sequence. Microfacies in the upper part of the Fahliyan Formation were mainly deposited in shallow (lagoon) to deeper water (open marine), and they form the last depositional sequence of the formation (sequence C). The results of this study reveal that the lower successions mainly were deposited coincided with a sea-level fall in the basin, while the sea level shows a slight rise during deposition of the middle units of the formation. However, the prevailing microfacies related to the shallow water environment, such as lagoon setting through the uppermost parts of the Fahliyan Formation, represent a fall in sea level at that time. This study shows that the Mongasht section (center of the study area) with microfacies associated with deep-water environments was the deepest part of the basin (depocenter). Hopefully, it is attempted to make a sequence stratigraphy framework to analyze the variations of microfacies and sedimentary environment and the reasons behind these changes for this formation.

进行了岩石学研究，以解释沉积相和环境特征的主要变化。基于这些研究，Fahliyan 地层识别出 16 个微相，这些微相沉积在斜坡台地的各个部分，包括潮滩、泻湖、浅滩和开阔的海洋环境。此外，应用解释的沉积环境和动物成分以及微相的沉积结构来识别三级沉积序列（序列A至C）。层序 A 是 Fahliyan 地层的最低部分，包括与浅滩和开阔海洋环境有关的沉积相。层序B构成地层的中部，开放海段被认为是该层序中大多数已识别微相的主要沉积环境。Fahliyan组上部微相主要沉积于浅水（泻湖）至深水（开阔海相），形成了该组最后的沉积层序（层序C）。研究结果表明，下部层序主要在盆地海平面下降期间沉积，而在地层中部单元沉积过程中海平面略有上升。然而，与浅水环境有关的盛行微相，例如通过 Fahliyan 组最上部的泻湖设置，代表了当时海平面的下降。本研究表明，具有与深水环境相关的微相的蒙加什特剖面（研究区中心）是盆地的最深部分（沉积中心）。希望，