The project area, nestled in Azad Jammu and Kashmir’s District Poonch, between Khirik and Thorar, as delineated by Pakistan’s Geological Survey toposheet no. 43G/9, boasts coordinates between latitudes 33˚49'30"N and 33˚52'00"N and longitudes 73˚39'00"E and 73˚45'00"E, with an elevation of 1638 meters above sea level (Yasin et al., 2017) . Renowned for its breathtaking beauty, Rawalakot, one of Kashmir’s most picturesque valleys, lies 80 kilometers equidistant from Rawalpindi and Islamabad, also known as “PEARL VALLEY”. The climate in Rawalakot is characterized by four distinct seasons: spring, summer, fall, and winter, with summer temperatures averaging between 25 to 35 degrees Celsius and winter lows dropping to 60 degrees Celsius (Shaheen et al., 2017; Malkani, 2020; Dar & Dubey, 2022) .

Geologically, the project region is situated in the Hazara Kashmir Syntaxis (HKS)’s eastern limb, with the Early Miocene Kamlial Formation being a prominent stratigraphic unit in the area (Khan et al., 2024b) . The region also features the marine sequence of the Eocene era, housing the Rawalpindi group, a part of the Neogene molasse sequence of the Kohat Plateau. Tectonic forces have led to the tight folding of rocks, resulting in narrow ridges (Hussain et al., 2021) . Noteworthy formations in the area include the Chinji, Nagri, Dhok Pathan, and Soan formations of the Siwalik Group, alongside the Murree and Kamlial formations of the Rawalpindi Group, all exposed in the Himalayan foreland Basin (Zaheer et al., 2022) .

The Rawalpindi Group, present in the study region, comprises formations like sandstone, siltstone, shales, and conglomerates, indicating less than 18 million years of river deposition, linked to the ancient Indus River (Ali et al., 2019) . The Miocene Murree and Kamlial Formations exhibit interbedded shales and sandstones, with distinct color variations and the presence of calcite veins in the sandstone (Javed et al., 2021; Khan et al., 2024a) . Petrological studies by (Mughal et al., 2018) have delved into the Murree Formation’s petrology, focusing on sandstone and shale characteristics, distinguishing between upper and lower Murree Formations based on grain size.

Previous studies have investigated various sandstone formations in Pakistan, aiming to understand their petrography (Ullah et al., 2006; Abbasi & Yasin, 2017) . (Khan et al., 2024c) conducted a detailed petrographic analysis of the Lumshiwal Formation in the Samana Range, Northwestern Pakistan, highlighting provenance, diagenesis, and depositional environments. Similarly, (Abbasi & Yasin, 2017) explored the petrography and diagenetic history of the Nagri Formation sandstone in District Bagh and Muzaffarabad, Pakistan, emphasizing the impact of diagenetic processes on sandstone reservoir quality. Furthermore, (Zaheer et al., 2022) investigated the sandstone petrology and provenance of the Siwalik Group in northwestern Pakistan and western-southeastern Nepal, providing insights into Neogene sedimentary succession and provenance attribution (Khan et al., 2023) .

While these studies contribute valuable insights into sandstone petrology and sediment provenance in Pakistan, they primarily focus on mineralogical analysis and diagenetic processes (Larsen & Chilingarian, 2010; Hashmi et al., 2018; Khan et al., 2024a) . In contrast, our research aims to extend this knowledge by conducting a comprehensive petrographic and geochemical analysis of sandstone samples from the Kamlial Formation. By integrating advanced analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and quantitative X-ray diffraction (QXRD), our study offers a detailed characterization of mineralogical composition, diagenetic processes, and sediment provenance in the Kamlial sandstone. This approach enables us to provide a more thorough understanding of the depositional history and hydrocarbon potential of the Kamlial Formation, contributing to the advancement of petroleum geology in Pakistan.

The project area exposes the geological age of molasse deposits. This stratigraphic profile is thoroughly detailed in Table 1 and comprehensively described as follows:

The research area lies in the eastern limb of Hazara-Kashmir Syntaxes (HKS) and represents the northwestern Himalayas as shown in Figure 1. The Himalayas are formed because of collision between Indian and Eurasian plates (Zhang et al., 2012) . The HKS is located to the south of Kohistan constitute a great regional bend which has caused inflection of the rocks of the western Himalayas and Hindu Kush (Ali et al., 2016) . The HKS is characterized by Panjal Thrust, Main Boundary Thrust, Jhelum fault and Kashmir Boundary Thrust as shown in Figure 1. The tectonic elements of the HKS are described below.

Only sedimentary rocks were included in the petrographic analysis. Sandstone samples, both new and representative, were collected from well-exposed rock units within the study area. In the lab, the thin sections were produced and examined under a microscope. Tables 2-4 give the modal mineralogical data of rocks. The texture of the sandstone in the Rawalpindi Group and Siwalik is fine to medium-grained. The color varies from greenish grey to grey. The sandstone is thinly laminated, thin to medium bedded. In primary structures, load casts,

potholes, hematite layers and worm burrows (as shown in Figure 8) are found in Kamlial Formation. Calcite concretion (as shown in Figure 9), hematite concretion (as shown in Figure 6), and filled and unfilled mud cracks are also found in the sandstone of the Kamlial Formation. Massive sandstone and shale

beds and conglomerates, micro conglomerates between sandstone beds, and laminated sandstone (as shown in Figure 5) and slump folding in sandstones (as shown in Figure 4). Local anticlines near Chappri Bazar are found in the Kamlial Formation. Intraformational clasts such as quartzite clast (as shown in Figure 7) are also found in the Kamlial Formation.

In the detailed analysis conducted on the sandstone sourced from the Kamlial Formation, an exhaustive investigation into its provenance has been precisely carried out, revealing invaluable insights into its geological origins. The diverse range of quartz grains, showcasing a spectrum of morphologies from sub-angular to sub-round, interspersed with occasional angular and stretched features, serves as pivotal evidence shedding light on the sedimentary processes that have shaped the sandstone over time. Notably, the observations of both strained and unstrained grains further deepen our understanding of the dynamic depositional environment that influenced the sandstone’s formation. Furthermore, the identification and characterization of feldspar minerals within the sandstone, including the discernment of plagioclase, perthite, and microcline, offer significant indications of the diverse array of source rock compositions contributing to the sandstone’s genesis. Through this comprehensive mineralogical analysis, we gain valuable insights into the complex interplay of geological factors that have culminated in the formation of sandstone.

Moreover, the recognition of various rock fragment types, spanning a wide spectrum of sedimentary, metamorphic, and igneous origins, is paramount for unraveling the intricate depositional history of the sandstone and elucidating its provenance. The presence of accessory minerals such as tourmaline, hornblende, epidote, chlorite, hematite, sericite, and opaque minerals further enriches the analysis, serving as critical indicators of the geological processes and source materials involved in the sandstone’s formation (Khan et al., 2024c) . Additionally, the identification of calcite and hematite as primary cementing materials provides illuminating insights into the diagenetic processes responsible for the consolidation of the sandstone, thereby augmenting our comprehension of its post-depositional alterations.

Comparing provenance analysis with QFL analysis reveals distinct approaches and perspectives in understanding sedimentary rocks’ origins. Provenance analysis focuses on deciphering the source regions of sedimentary deposits by examining mineralogical composition, rock fragment types, and accessory minerals (Cheng et al., 2019; Khan et al., 2024c) . This method provides detailed insights into the geological processes and environments responsible for sediment formation. In contrast, QFL analysis primarily quantifies the relative abundance of quartz, feldspar, and lithic fragments in sedimentary rocks, offering a simplified yet quantitative assessment of sediment composition (Huber & Bahlburg, 2021) . While provenance analysis offers a more comprehensive understanding of depositional history and source materials, QFL analysis provides a quick and standardized method for characterizing sedimentary rocks, particularly in large-scale studies or when detailed mineralogical data is not required (Hussain et al., 2021) . Each approach has its advantages and limitations, making them complementary tools in sedimentary geology research.

In conclusion, our study of the Kamlial Formation’s sandstone has yielded several significant insights into the geological dynamics of the Sub-Himalayan Hazara Kashmir Syntaxis. We have identified a gradual transition between Siwalik and Rawalpindi group formations in the Khirik and Thorar districts of Poonch, along with the absence of key formations in the project region. The presence of intraformational microconglomerates and hematite concretions suggests a shift towards arid and semiarid environmental conditions in the Himalayan foreland basin. Tectonic forces have played a crucial role, formed a thorium anticline and influencing regional geological structures. Our detailed petrological analysis has delineated distinct lithic wacke and lithic arenite facies, providing valuable insights into their composition and origin. Additionally, the diversity in quartz grain shapes indicates a complex sedimentary history, with contributions from both proximal and distal sources. The presence of interformational and intraformational clasts further emphasizes the composite nature of sedimentary deposition in the region. Moving forward, our findings have implications for broader geological and environmental studies in the Himalayan foreland basin. Future research efforts could focus on refining provenance analysis techniques and exploring the wider implications of these discoveries for understanding the dynamic geological processes shaping the region.

This work was supported by the National Natural Science Foundation of China (41830752, 42071033).

The authors declare no conflicts of interest regarding the publication of this paper.

Mehmood, E., Lv, H. S., Gao, P., & Qamar, S. (2024). Petrology and Petrographic Delineation of Kamlial Formation Sandstone Mong and Thorar Village, Northern Pakistan. Journal of Geoscience and Environment Protection, 12, 302-324. https://doi.org/10.4236/gep.2024.125017