Cretaceous stratigraphic framework and sedimentary architecture, Pakistan: signatures of rift–drift tectonics and submarine volcanism along the western continental margin of the Indian Plate

Abstract

Abstract The lithostratigraphy, biostratigraphy and depositional environments of the Cretaceous successions in Pakistan were investigated to reveal the major geological events, including local, regional and global-scale tectonics, phases of volcanism, basin condensation, emergence of structural highs and episodes of non-deposition. The succession is entirely missing at Salt Range but is excellently exposed in the Kirthar–Sulaiman Fold-Thrust belts. Such deviating nature (e.g. Hazara, Kala Chitta, Surghar and Kohat), suggesting episodical tectonic activities, is associated with inter–intra rifting and drifting of the India–Madagascar–Seychelles and Antarctica–Australian plates during the Cretaceous. Correspondingly, several unconformities within the Cretaceous succession at numerous stratigraphic intervals consistently attest to the effect of tectonics throughout the period. The recognized unconformities over Kawagarh, Lumshiwal, Parh and Fort Munro formations testify to episodic uplifts on local and/or regional scales during the Coniacian–Santonian, Coniacian–Maastrichtian, Campanian and Maastrichtian in response to the separation of Madagascar from the India–Seychelles Plate. In contrast, there was continuous sedimentation of carbonate, clastic and/or submarine volcanics in the Kirthar and Indian–Eurasian suture zone. Significant geological events in the restricted regions, e.g. local-scale submarine volcanism (Bibai Formation), ironstone deposition (Dilband Formation) and basin condensation (Khuzdar), were also associated with such rifting–drifting phases along the WNW margin of the Indian Plate.