Biomarker and Carbon Isotopic Evidence of Marine Incursions in the Himalayan Foreland Basin During Its Overfilled Stage

Abstract

Peripheral foreland basins, an elongated trough between linear contractional orogenic belts and stable cratons, are developed due to downward flexural subsidence of the cratonic lithosphere driven by thrustsheet loading of the overriding mountain range (DeCelles, 2012;DeCelles & Giles, 1996;Lyon-Caen & Molnar, 1985). The difference in thrust loading across the fold-thrust belt results in the spatial and temporal variation of sedimentation within the foreland basins (DeCelles & Giles, 1996;Flemings & Jordan, 1989;Kumar et al., 2003a;Waschbusch & Royden, 2007). During the initial underfilled stage, sediments from marine and deltaic settings are commonly deposited in the foreland basins. Eventually, in the overfilled stage, the marine deposits are replaced by the fluvial-dominating environments with sediments sourced

Asian monsoon and vegetation shift: evidence from the Siwalik succession of India

“…Calcutta, 2012;Khan et al 2016;More et al 2018). However, recent works based on lithostratigraphy, magnetostratigraphy and sub-basin correlation assigned the age of the Lower (Gish Clay Formation) and Middle (Geabdat Sandstone Formation) Siwalik of Darjeeling to the middle Miocene and late Miocene-Pliocene, respectively (Acharyya, 1994;Taral et al 2017;Chakraborty et al 2020;Roy et al 2021).…”

“…The sediments of the western and central regions are exclusively terrestrial and were deposited by meandering and braided rivers (DeCelles et al 1998;Nakayama & Ulak, 1999;Kumar et al 2003aKumar et al ,b, 2011. However, the depositional environment of the eastern Siwalik has some marine influence (Mitra et al 2000;Chirouze et al 2012;Coutand et al 2016;More et al 2016;Taral et al 2017;Roy et al 2021). This dissimilarity is referable to the fact that the eastern region of India was not connected to Eurasia in the way that the western and central regions were before middle Miocene time (Sinha et al 1982;Ranga Rao, 1983).…”

Provenance Shifts During Neogene Brahmaputra Delta Progradation Tied to Coupled Climate and Tectonic Change in the Eastern Himalaya

“…Debnath et al (2021) proposed a significant marine incursion between deposition of the Upper and Middle Siwalik sub-Groups based on interpretation of complex bedforms in sandstone and siltstones associated within Upper Siwalik conglomerates. Recent carbon isotope analyses, however, argue against marine incursions of the Himalayan foreland after the Pliocene (Roy et al, 2021). Generally, the Upper Siwalik has been interpreted to reflect Pleistocene foreland progradation of wet alluvial fans fed by transverse river drainages (Burbank, 1992;Lang et al, 2016).…”

Carbon reservoir perturbations induced by Deccan volcanism: Stable isotope and biomolecular perspectives from shallow marine environment in Eastern India

“…The marine Units 2 and 3 are marked by only ~0.6‰ higher δ 13 C org value compared to underlying paleosol Unit 1 (Figure 5b). The δ 13 C org values of modern marine OM is usually 3‰ to 4‰ higher compared to coeval land plants (Roy et al, 2021). Since OM in shallow marine sediments is sourced from both marine and terrestrial environments, higher amount of terrestrial OM contribution can lead to lowering in the δ 13 C org values of bulk OM in marine sediments, especially during low autochthonous production.…”