In this paper, the depositional environment, age, and tectonic context of the Sub-Himalayan Kuldana Formation are discussed in detail. To determine the Kuldana Formation’s depositional environment, age, and tectonic setting, sedimentological, palaeontological, and petrographic investigations have been conducted accordingly. The Kuldana Formation lithologically consists of both siliciclastic and carbonate rocks. Petrographically, the Kuldana Formation’s sandstone is divided into litharenite and feldspathic litharenite petrofacies. The sandstone plots on the QtFL and QmFLt suggest that the sandstone of the Kuldana Formation derived from a recycled orogen provenance field that developed during the collision of the Indian and Eurasian plates in the Lesser and Higher Himalayas. The plots in the diamond diagram further demonstrate that the detritus of the Kuldana Formation was derived from low and middle-to-upper rank metamorphic rocks of the Himalayas. Throughout the deposition of sandstone, paleo-climate conditions were semi-humid to semiarid. Dolostone and limestone are the two main types of carbonate rocks found in the Kuldana Formation. According to Dunham’s Classification, the Kuldana Formation limestone is classified as mudstone, wackstone, and packstone. These petrofacies suggest that the limestone was deposited in an inner-outer ramp setting. The bioclasts include bivalves, brachiopods, crinoid, gastropods, Globigerinoides spp., Lockhartia pustulosa, miliolids, Nummulites atacicus, Nummulites discorbina, Nummulites mamillatus, Nummulites djodjokartae, Nummulites vascus, and ostracods suggesting that the age of Kuldana Formation is Middle Eocene-early Oligocene. The Kuldana Formation was deposited during the initial stages of the Himalayan Orogeny as a result of the Ceno-Tethys Ocean’s regression and transgression, as revealed by a succession of siliciclastic and non-clastic rocks.

The present study provides a detailed compilation and analysis of the bulk density and magnetic susceptibility of the rocks from the northwest Himalayas, Pakistan. The area is tectonically extremely complex and comprises sedimentary, metamorphic, and igneous rocks. These rocks range in age from Early Proterozoic to Recent. During the fieldwork, 476 rock samples were collected for density measurements and 410 for magnetic susceptibility measurements from the major rock units exposed in the study area. The measured physical parameters reveal a significant difference in the density and susceptibility of the rocks present in the investigated area. The sedimentary rock units belonging to the Indian Plate show the lowest mean values for bulk density, followed by metasedimentary rocks, Early Proterozoic rocks, igneous and metaigneous rock units of the Indian Plate, Indus Suture Melange Zone, and Kohistan Island Arc rocks, respectively. The magnetic susceptibility of sedimentary rock units of the Indian Plate has the lowest mean values, followed by metasedimentary rocks of the Indian Plate, igneous and metaigneous rock units of the Indian Plate, Early Proterozoic rocks of the Indian Plate, Kohistan Island Arc rocks, and Indus Suture Melange Zone. In brief, the sedimentary rocks of the Indian Plate have the lowest bulk density and magnetic susceptibility values, whereas the Kohistan Island Arc rocks have the highest values. Overall, the bulk density and magnetic susceptibility of rock units in the study area follow those predicted for different types of rocks. These measurements can be used to develop possible potential field models of the northwest Himalayas to better understand the tectonics of the ongoing continental-to-continental collision, as well as for many other geological analyses.