Vol.:(0123456789) 1 3 Carbonates and Evaporites (2020) 35:123 https://doi.org/10.1007/s13146-020-00662-w ORIGINAL ARTICLE Sedimentological attributes of the Middle Jurassic peloids‑dominated carbonates of eastern Tethys, lesser Himalayas, Pakistan Abdus Saboor 1,2  · Muhammad Haneef 3  · Muhammad Hanif 4  · Muhammad Azhar Farooq Swati 2 Accepted: 15 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract The carbonate factories of the tropical to sub-tropical regions characterize a number of facies, attributable to biological and oceanographic variables. For this purpose, the Middle Jurassic carbonate rock unit (Samana Suk Formation) of the Upper Indus Basin of Pakistan was studied to understand the various Tethyan platform attributes. Four sections from Hazara area were chosen which were also compared with a section from the Nizampur Basin. The resultant microfacies were placed in their paleoenvironmental settings to reveal the facies distribution and geometry of the platform. The platform represents a gen- tly dipping ramp, dominated by peloidal–bioclastic–ooidal grainstones and peloidal lime mudstones. The allochems and fauna show some contrasting signatures regarding paleoclimate. These microfacies infer about existence of a relatively extended tropical climatic belt in the paleo Tethys during the Middle Jurassic. The notable presence of planktonic lime mudstone facies corresponds with global marine transgression, occurring in the middle of rock unit. The nature of ooids and types of fauna of sub-tropics to tropics advocate an extended warm climatic zone in comparison with today. The dominance of gently dipping inner-ramp shoals accompanied by lagoons to steep dipping outer-ramp planktonic lime mudstones restricted the development of least encountered middle-ramp facies. The ramp platform was struck by waves and tides of diferent strengths including low-middle amplitude storms and the overall absence of evaporites and primary dolostones designate a humid region as manifested by euryhaline conditions. The study has drawn paleoenvironmental and palaeoceanographic similarities with sections in Tanzania, western India, NW Iran, NW Afghanistan and Western Australia. The oceanic parameters compare with present day Trucial Coast of Persian Gulf, refecting an almost similar nature of paleoceanography in the paleo Tethys. Keywords Samana Suk · Jurassic · Tethys · Pakistan · Himalayas · Ooids Introduction The carbonate factories of ancient tropical to sub-tropical platforms have resulted in a wide variety of facies through geological time owing to a combined biological, geomor- phological and oceanographic variabilities. These platforms have similarities in terms of their geometry and architecture and are broadly analogous. The Cambrian life explosion is caused by development of extended carbonate platforms giv- ing rise to a variety of facies. Many researchers (e.g., Budd and Loucks 1981, Alsharhan 1993, Alsharhan and Nairn 1994, Alsharhan and Kendall 2003, Cantrell 2006, Brigaud et al. 2009, Pratt et al. 2011, Aghaei et al. 2012, Wetzel et al. 2013, Lokier and Junaibi 2016, Purkis and Harris 2017, and Wohlwend et al. 2017) have worked on diferent aspects of carbonate platforms. The aspects include facies distribution, depositional modeling, paleoenvironmental changes and sediment distribution patterns of various modern and ancient shallow-marine ooidal–peloidal carbonate platforms. Ramp platforms are important parts of many carbonate succes- sions and are widespread in the geological record, particu- larly common during Jurassic times (Burchette et al. 1990). The ramp deposits contain signifcant hydrocarbon reserves (Pierre 2010) and oolitic ramp systems form important reser- voirs such as Jurassic Smackover Formation (US Gulf Coast) * Abdus Saboor abdus.saboor@uop.edu.pk 1 School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China 2 Department of Geology, University of Peshawar, Peshawar 25120, Pakistan 3 Department of Earth Sciences, Comsats Institute of Information Technology, Peshawar, Pakistan 4 National Centre of Excellence in Geology, University of Peshawar, Peshawar, Pakistan