Petrography and Lithofacies of the Siwalik Group in the Core of Hazara-Kashmir Syntaxis: Implications for Middle Stage Himalayan Orogeny and Paleoclimatic Conditions

Abstract

The present field and petrographic investigations of the Tortonian to Gelasian Siwalik Group in the southwestern region of the Hazara-Kashmir Syntaxis have been carried out to comprehend the middle stage Himalayan orogeny that resulted from the collision of Indian and Asian plates. The Chinji, Nagri, Dhok Pathan, and Soan Formations of the Siwalik Group were deposited by river meandering flood plains, braided rivers, and alluvial fan systems, respectively. The Siwalik Group is classified into seven major facies and many minor facies based on sedimentological properties. According to the petrographic analysis, the Siwalik Group sandstone is classified as litharenite and feldspathic litharenite petrofacies. The sandstone of the Siwalik Group is texturally mature, but compositionally it is immature. The data shown on the tectonic discrimination diagrams point to a recycled orogen provenance field for the Siwalik sandstone. In addition to quartz and feldspar, the sandstone includes clasts of volcanic, metamorphic, and sedimentary rock types. The igneous and metamorphic rock clasts were derived from the Lesser and Higher Himalayas. The sedimentary lithic fragments, on the other hand, are derived from both the earlier molasse and pre-molasse rocks. The presence of lithic fragments of the earlier molasse sandstone in the Siwalik sandstone indicates that the Siwalik Group sandstones were deposited during the Middle Stage of the Himalayan orogeny. The paleoclimatic conditions were semi-arid to semi-humid during the Siwalik Group’s deposition. The presence of clay minerals in the shale reveals the intense chemical weathering processes that occurred during their deposition on the flood plains of the river meandering system.

Sedimentary and Diagenetic Controls across the Cretaceous—Paleogene Transition: New Paleoenvironmental Insights of the External Ionian Zone from the Pelagic Carbonates of the Gardiki Section (Epirus, Western Greece)

“…The microfacies' definition and textural characters analysis of the carbonate rocks were defined according to Dunham [41] classification scheme, which were later modified by Embry and Klovan [42] and Flügel [43], based on the Standard Microfacies Types (SMF) in the Facies Zone (FZ) of the rimmed carbonate platform model. Depositional paleoenvironments were reconstructed based on the observed sedimentological characteristics during fieldwork and interpreted sedimentary facies analysis, and through comparison with additional outcropped data known from the existing literature on time equivalent deposits of the Ionian basin [18][19][20]44,45], as well as other environmental studies [46][47][48][49][50][51][52][53][54]. The study part of Gardiki section consists of Late Cretaceous-Early Paleocene pelagic deposits, such as pelagic limestones and radiolarian chert horizons.…”

Determination of Dynamic Properties of Fine-Grained Soils at High Cyclic Strains

“…Most of the earthquakes that affect Peshawar have their origin in the Hindu Kush region of Afghanistan or the northern areas of Pakistan [28][29][30]. The Hazara-Kashmir syntax is connected to the Punjal fault, Jhelum fault, and Main Boundary Thrust (MBT) [31][32][33]. It is a very active fault and contributes to most of the seismicity of Peshawar.…”

Sedimentological Controls on the Reservoir Characteristics of the Mid-Triassic Tredian Formation in the Salt and Trans-Indus Surghar Ranges, Pakistan: Integration of Outcrop, Petrographic, and SEM Analyses

“…The TIR comprises the Surghar Range, the Shinghar Range, the Marwat-Khisor Ranges, the Manzai Range, and the Sheikh Badin Hills. The Surghar Range (SR) marks the eastern extremity of the Trans-Indus Ranges [28,29] (Figure 1).…”