Record of Leaf and Pollen cf. Sloanea (Elaeocarpaceae) from the Middle Siwalik of Darjeeling sub-Himalaya, India and its Palaeobiogeographic Implications

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

“…A variation of 4‰-10‰ is observed between the δ 13 C n-alkane values of individual odd-HMW carbon homologs (Figure 3). The considerable temporal difference in δ 13 C n-alkane values in the long-chain is suggestive of variation in C 3 /C 4 plant contribution (C 3 = −34.1 ± 2.2‰ and C 4 = −18.9 ± 2.5‰; Roy et al, 2020a), which corroborates the observations made from fossil leaves recovered from the Tista valley sediments (Khan et al, 2016;More et al, 2018;Paruya, 2012). It is also important to note that the odd HMW n-alkanes of terrestrial origin are depleted (1-3‰) in 13 C relative to adjacent even carbon numbered n-alkanes (Murray et al, 1994;Tipple et al, 2011).…”

“…and invertebrate ( Globigerenoids sp .) fossil assemblages suggest a depositional period between middle Miocene and Pliocene in the Tista valley (Acharyya et al., 1979; Khan et al., 2016; More et al., 2018; Paruya, 2012). In this study, a relative depositional age of the Tista valley sequence was constrained by comparing with paleomagnetic ages of the Siwalik deposits at Muksar Khola area, eastern Nepal (∼50 km strike parallel east of present study area).…”

“…The paleo‐depositional interpretation from the invertebrate fossils was further challenged due to their limited occurrence and the possibility of its derivation from the older Himalayan tertiary rocks (Acharyya et al., 1987). Recently, efforts have been made to reconstruct the past environmental conditions using ichnofossils (Chakraborty et al., 2013; More et al., 2018; Taral et al., 2018, 2019; Ulak, 2009). Specific ichnogenera traces in pre‐requisite amounts are considered as important paleo‐environmental markers (MacEachern et al., 2008).…”

“…The preliminary sedimentological investigations provided contradictory evidence of both terrestrial and marine paleo‐depositional conditions in the eastern part of HFB (Banerjee & Banerjee, 1982; Coutand et al., 2016; Kundu et al., 2011, 2012, 2016; Mandal et al., 2014; Taral & Chakraborty, 2018; Taral et al., 2017, 2019). Pollen and leaf‐macrofossils have been widely used to suggest an exclusive terrestrial environment, although rare and punctuated occurrences of mangrove taxa have indicated coastal settings (Coutand et al., 2016; Joshi et al., 2003; Khan et al, 2016, 2019, 2016; More et al, 2016, 2018; Paruya, 2012). However, pollens can be transported from elsewhere and can also be re‐deposited from older sediments; hence their presence alone cannot be used as conclusive paleo‐environmental evidence (Keating, 1992; Wilson, 1964).…”

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

“…Ph.D. thesis, Univ. 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).…”