Stratigraphy and Sedimentation of the Jurassics in North-Eastern Baluchistan

Abstract

Northeastern Baluchistan may be conveniently divided into two major structural zones, a northern imbricated allochthonous zone characterized by extensive thrust faults and a southern autochthonous fold belt which is mainly comprised of simple folds. The Jurassic sediments exposed in these two zones differ structurally as well as lithologicaly. In the allochthonous zone the imbricate structure has resulted in repetition and thickening of beds as well us cropping out of Triassic and earlier strata. In this zone the Jurassics are mainly comprised of thick to thin bedded limestone interbedded with shales. In the allochthonous zone, such as the Ziarat-Harnai region, an undisturbed thick succession (133 m plus.) of Jurassic strata comprising the Mazar Drik Formation, the Chiltan Limestone and the Shrinab Formation is seen in the core of major anticlines. The Mazar Drik Formation is exposed in the Mehrab Tangi, south of Ziarat, but in the Khalifat Range it is missing due to a major Late Jurassic unconformity. In this paper the stratigraphy, sedimentary structures, and palaeogeography of the Jurassics of the Ziarat area have been described.