Late Permian Mixed Carbonate-Siliciclastic Sedimentary Succession on the Northwestern Margin of the Indian Plate, Pakistan: Insights into Facies Evolution and Paleoenvironmental Reconstruction of the Chhidru Formation

Abstract

This study investigates the facies development and sedimentology of the Late Permian Chhidru Formation, a mixed carbonate-siliciclastic unit exposed in the Western Salt Range, Potwar Basin, Pakistan. The formation is subdivided into four lithological units reflecting lateral variability, with thicknesses and lithologies ranging from fossiliferous sandy limestone to interbedded limestone and sandstone. These successions record a depositional shift from a carbonate platform to mixed carbonate-clastic, and ultimately, clastic-dominated environments. Lithostratigraphy suggests deposition on the underlying Wargal Limestone carbonates during a Late Permian sea-level fall on the northwest Indian margin of Gondwana. Similar Permian successions with identical lithological characteristics are documented in the Persian Gulf (Dalan Formation), Arabian Platform (Khuff Formation), and Iran (Nesen and Hambust formations). Petrographic analysis reveals deposition in the distal middle to proximal inner shelf settings of a carbonate-siliciclastic mixed, unrimmed platform. Based on identified foraminiferal assemblages, the Chhidru Formation's age is estimated to range from the late Wuchiapingian to Changhsingian stages of the Lopingian epoch.

Keywords

facies analysis / depositional setting / Chhidru Formation / Salt Range / Pakistan

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2026 Geological Society of China