Sedimentology and Geochemistry of the Early Cambrian Hazira Formation in the Haripur Region, Lesser Himalayas, Pakistan

Sedimentology, petrography, and major and trace element analysis are explored in the early Cambrian Hazira Formation, Haripur, Lesser Himalayas, North Pakistan, to ascertain the paleoenvironment, origin, paleo-weathering intensity, and tectonic settings. Greywacke sandstone, siltstone, shale, argillite, claystone, limestone, and coarsening are the main geological features of the Hazira Formation. These rocks likely exhibit varying diagenetic grades, influenced by differences in burial history and diagenetic processes. Geochemical analysis of the early Cambrian Hazira Formation was conducted to determine its origin and tectonic setting. The analysis also provides insights into the source region weathering and its implications for the depositional environment. Quartzose sedimentary source rocks with a range of compositions from felsic to intermediate are indicated by major element chemistry. Plots of the Hazira Formation’s principal element composition on tectonic setting discrimination diagrams indicate that the Hazira Formation was deposited on the passive continental margin. The analysis of the SiO2 wt.% vs (Al2O3 + K2O + Na2O) wt.% bivariate diagram values of the analyzed samples indicate that there was considerable chemical weathering in the source region that led to the production of mature sandstone. The cyclic pattern of sedimentation is represented by the alternating sandstone, siltstone, shale, argillite, and mudstone, reflecting fluctuations in depositional energy. Coarser materials are deposited in higher-energy environments (e.g., turbidity currents), while finer materials accumulate in low-energy conditions (e.g., quiet marine deposition). These cycles likely result from fluctuations in sea level or sediment supply, indicating a dynamic depositional environment. It has been established by thorough sedimentary facies analysis that the sequence was deposited in a shallow to deep marine environment. The petrographic data indicate that 60–70% of the sandstone unit is composed of quartz. According to the QFR diagram, the sandstone is categorized as mature quartz sandstone, consistent with the geochemical analysis showing a quartzose provenance. The higher amount of quartz in the sandstone and siltstone suggests that it has a weathered felsic provenance.