Quaternary International 629 (2022) 65–73 Available online 29 January 2021 1040-6182/© 2021 Elsevier Ltd and INQUA. All rights reserved. Paleomonsoonal shifts during ~13700 to 3100 yr BP in the central Ganga Basin, India with a severe arid phase at ~4.2 ka Shweta Singh a , Anil K. Gupta b, *, 1 , Suman Rawat a , Ajoy K. Bhaumik c , Pankaj Kumar d , Santosh K. Rai a a Wadia Institute of Himalayan Geology, 33 General Mahadeo Singh Road, Dehradun, 248001, India b Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India c Department of Applied Geology, Indian Institute of Technology (Indian School of Mines) Dhanbad, 826004, India d Inter University Accelerator Center (IUAC), New Delhi, India A R T I C L E INFO Keywords: Indian monsoon Lilaur lake Grain size El Ni˜ no ITCZ Vegetation change ABSTRACT We present a multiproxy record of grain size and stable carbon isotope from the Lilaur lake, Ganga Basin, India to understand the history of lake formation linked to changes in Indian monsoon precipitation during ~13714 to 3073 calibrated year before Present (cal yr BP). A comparison is made between Lilaur lake proxy record with those from other parts of South Asia as well as North Atlantic to understand extent and causes of monsoon variability and its influence on the fauna and flora of the region. Chronology of lake core was constrained using AMS 14 C and optically stimulated luminescence (OSL) dates. This study suggests a transition from river to lake during ~5800 to 5189 cal yr BP which is supported by reduced precipitation with weakening of the Indian summer monsoon (ISM). This river to lake transition culminated in a severe arid phase during 4250 to 4050 cal yr BP (4.2 ka event), corresponding to enhanced El Ni˜ no activity, southward shift of the Inter-Tropical Convergence Zone, and aridification of India when the ISM was weak. 1. Introduction The world’s thickest Quaternary sediments have been deposited in the Ganga Basin (Indo-Gangetic plain), which are highly fertile for agriculture productivity, catering to the monsoon governed economy of the Indian subcontinent (Bhattacharya and Banerjee 1979; Srivastava et al., 2001; Sinha et al., 2007; Singh and Awasthi 2011a; Singh et al., 2015; Saxena et al., 2017). Geomorphologically, from north to south the Ganga Basin consists of four diverse regions, e.g., i) Bhabar Belt (adja- cent to the Himalaya), ii) Terai Belt (characterized by development of wide-range of ponds, and swamps), iii) Central Alluvial Plain (located between Bhabar and Terai, marked by SE direction of drainage system) and iv) Marginal Alluvial Plain (adjacent to Peninsular craton) (Singh et al., 1996; Singh and Singh, 2005). The Terai region is characterized by numerous lakes formed due to channel relinquishment owing to changes in the course of major river channels and tectonic activities during the early-middle Holocene (~8–5 ka) as well as beginning of an arid phase in the late Holocene (Srivastava et al., 2003; Singh et al., 2015; Saxena et al., 2017; Dixit et al., 2014; Dutt et al., 2018; Trivedi et al., 2019). Thus these lakes preserve prominent archives of Holocene climate his- tory, tectonic activity and channel shifts in the Ganga Basin (Srivastava et al., 2003). Numerous high-resolution studies have been carried out to recon- struct monsoon variability using marine records from the Arabian Sea (Schulz et al., 1998; Overpeck et al., 1996; Anderson et al., 2002; Gupta et al., 2003), lake records from the Himalaya (Kotlia and Joshi 2013; Rawat et al., 2015; Dutt et al., 2018), speleothem records from Oman and Indian Himalaya (Fleitmann et al., 2003; Sinha et al., 2005; Sanwal et al., 2013; Dutt et al., 2015; Kathayat et al., 2017) and tree rings in South Asia (Yadava et al., 2004; Shah et al., 2007). However, only a few large-scale high resolution studies have been carried out from fresh water lakes located in the Ganga Basin which produced excellent lacustrine archives to constrain changes in the Indian monsoon and their impact on major river channels leading to lake for- mation in the region (Chauhan et al., 2015; Trivedi et al., 2019). To fill this gap, we selected two sites in the Lilaur lake (LIL-1, LIL-2) and collected top 50 m sediment cores from these two sites to analyze grain size and stable carbon isotope ratio (δ 13 C) to understand past monsoon * Corresponding author. IIT Campus, Indian Institute of Technology, Kharagpur, 721302, India. E-mail address: anilg@gg.iitkgp.ac.in (A.K. Gupta). 1 Formerly at Wadia Institute of Himalayan Geology, Dehradun, India. Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint https://doi.org/10.1016/j.quaint.2021.01.015 Received 19 June 2020; Received in revised form 14 January 2021; Accepted 20 January 2021