Mid- to late Holocene climate response from the Triloknath palaeolake, Lahaul Himalaya based on multiproxy data

    Mid-to late Holocene climate response from the Triloknath palaeolake, Lahaul Himalaya based on multiproxy data Rameshwar Bali, Imran Khan, S.J. Sangode, Amit K Mishra, S Nawaz Ali, Saurabh K. Singh, Jayant K.Tripathi, Dhruv Sen Singh, Purnima Srivastava PII: DOI: Reference:

S0169-555X(16)30999-0 doi: 10.1016/j.geomorph.2016.10.028 GEOMOR 5815

To appear in:

Geomorphology

Received date: Revised date: Accepted date:

5 May 2016 16 October 2016 19 October 2016

Please cite this article as: Bali, Rameshwar, Khan, Imran, Sangode, S.J., Mishra, Amit K, Ali, S Nawaz, Singh, Saurabh K., K.Tripathi, Jayant, Singh, Dhruv Sen, Srivastava, Purnima, Mid-to late Holocene climate response from the Triloknath palaeolake, Lahaul Himalaya based on multiproxy data, Geomorphology (2016), doi: 10.1016/j.geomorph.2016.10.028

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ACCEPTED MANUSCRIPT Mid-to late Holocene climate response from the Triloknath palaeolake, Lahaul Himalaya based on multiproxy data

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Rameshwar Balia*, Imran Khana, S.J.Sangodeb, Amit K Mishraa, S Nawaz Alic,d , Saurabh

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K. Singhe, Jayant K.Tripathie, Dhruv Sen Singha and Purnima Srivastavaa Centre of Advanced Study in Geology, University of Lucknow, Lucknow-226007, India

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Department of Geology, Savitribai Phule Pune University, Pune- 411007, India

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Birbal Sahni Institute of PalaeoSciences, 53 University Road, Lucknow- 226007, India

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Physical Research Laboratory, Ahmedabad -380009. India

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School of Environmental Sciences, Jawaharlal Nehru UniversiSSty, New Delhi-110067 India

*Corresponding author. Tel.: +919415111803

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E-mail addresses: [email protected]

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Abstract

A 2.13-m-thick palaeolake sequence deposited between the right lateral moraine and the valley

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wall of Triloknath glacier, has been studied at high resolution to understand the past climatic changes in Lahaul Himalaya. The OSL and AMS 14C chronology suggests that the lake building

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activity was initiated post-cooling phase since ~6484 cal. YBP. The combination of sedimentological, geochemical, and environmental magnetic parameters helped to infer five first-order climatic zones. The influx of magnetic minerals along with a notable increase in antiferromagnetic mineralogy (appearance of hematite) and higher chemical index of alteration (CIA) values during ~5925 cal. YBP to 5676 cal. YBP suggests warm and wet conditions owing to enhanced Indian Summer Monsoon (ISM) precipitation corresponding to the mid- Holocene warming. Further, reduction in the magnetic mineral concentration with few peaks of antiferromagnetic mineralogy and higher CIA values suggests warmer episodes within an overall cold climate, and the finer ferrimagnetic grain size suggests intermittent low energy and ponding conditions during ~ 3904 cal. YBP to 2365 cal. YBP. This was followed by fluctuating cold arid 1

ACCEPTED MANUSCRIPT conditions in response to reduced ISM precipitation during ~ 2365 cal. YBP and 1758 cal. YBP. Further, between 1758 cal. YBP to the present, episodic warming, pedogenic enhancement, and

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increased monsoon precipitation have been recorded. A major warm episode (Medieval warm

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period) as depicted from enhanced antiferromagnetic mineralogy and higher CIA values has

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been recorded between ~ 742 cal.yrs. BP and 593 cal. YBP. The sudden drop in the magnetic mineral concentration as well as the CIA value, around ~ 300 cal. YBP (A.D. 1650) is likely because of colder conditions prevailing during the Little Ice Age (LIA). The study illustrates

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glaciated regime of the Triloknath glacier.

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high sensitivity of the lake sediment sequence to witness the climatic episodes experienced in the

Keywords: Triloknath palaeolake; Lahaul Himalaya; Holocene palaeoclimate; multiproxy data Introduction

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1.

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The high mountain glaciers are one of the most sensitive recorders of climate changes (Kääb et al., 2007; Schaefer et al., 2008) because they have the tendency to respond to the

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combined effect of snowfall and temperature (Pratt-Sitaula et al., 2011).

The Himalayan

mountain chain extending for almost 2400 km has more than 12,000 valley/mountain glaciers all

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along its length (Raina and Srivastava, 2008; Sangewar and Shukla, 2009). Mountain glaciers develop landforms and provide valuable evidence of cryosphere evolution (Bali et al., 2003; Schaefer et al., 2008; Zhao et al., 2009; Yao et al., 2012; Singh, 2014; Singh et al., 2016). Himalayan glaciers are mostly nourished by moisture from two major weather systems viz., Indian Summer Monsoon (ISM) and the Mid-Latitude Westerlies (MLW) (Owen et al., 1996; Benn and Owen, 1998; Yang et al., 2008; Juyal et al., 2009; Ali and Juyal, 2013; Ali et al., 2013; Sati et al., 2014). A large part of the southern, central, and eastern Himalaya receives summer precipitation from the ISM, and hence the glaciers present in these regions are referred to as summer accumulation type glaciers. From west to east, the Himalayan range has a decreasing influence of the MLW and an increasing influence of the ISM (Bookhagen et al., 2005), leading 2

ACCEPTED MANUSCRIPT to distinct precipitation regimes on glaciers depending on their location. At present, the glaciers in the extreme western Himalaya, Trans-Himalaya, and Tibetan Plateau are mainly fed by winter

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precipitation, the moisture being supplied by the MLW (Benn and Owen, 1998; Ali and Juyal,

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2013).

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Long-term precipitation data are lacking for having a proper understanding of moisture sources for glaciers falling on the southern and the northern slopes of Pir Panjal Range acting as an orographic barrier. Some of the recent studies suggest that the orographic barrier ranging in

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altitude between 4000 and 6600 m is responsible for the existence of entirely two different

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precipitation regimes in the Lahaul Himalaya (Wulf et al., 2010). The studies of temporal and spatial moisture gradients of the northwestern Himalaya (Weiers, 1995; Wulf et al., 2010; Azam

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et al., 2014; Pandey et al., 2016) suggest that although the MLW and the ISM contribute to the

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average annual precipitation, the northern face of the orographic barrier receives nearly 80% of winter precipitation from the northern westerlies, whereas the southern face receives most of its

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precipitation from the Indian Summer Monsoon. Further suggestions have been made that in spite of the present-day dominance of westerly derived moisture, sporadic heavy monsoonal

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rainstorms dominate the fluvial sediment flux in the orogenic interior (Wulf et al., 2010). During intensified monsoon phases in late Pleistocene and Holocene time, moisture migrated into the high arid parts of the northwest Himalaya compared to present-day weaker monsoon conditions (Gasse et al., 1991; Bookhagen et al., 2005a,b, 2006). Climatic reconstruction and correlation of the palaeoclimatic variations in the high-mid-latitude and the low latitude tropical regions have shown that the different climatic systems have reacted to the same cause like the solar output variations either independently or via teleconnections (Bond et al., 2001; Haug et al., 2001; Johnsen et al., 2001; Anderson et al., 2002; Gupta et al., 2003; Hong et al., 2003; Soon et al., 2014). The palaeoclimatic reconstructions in several peripheral ISM regions do not clearly indicate if the variation in moisture availability was exclusively linked to the change in ISM or 3

ACCEPTED MANUSCRIPT to the altered winter westerly precipitation (Menzel et al., 2014). Gupta et al. (2003) while suggesting a link between North Atlantic climate and the Asian monsoon have opined that most

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recent cycles in the North Atlantic have counterparts in the Asian southwest monsoon. While

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synthesising the climatic variability data of the Indian subcontinent, Dixit and Tandon (2016)

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suggested that the Warm Eurasian landmass during the Medieval Warm Period (MWP) has contributed to increased transport of warm water to the North Atlantic, in turn warming the ocean and the adjacent landmass. This intensified the thermal gradient between the Indian Ocean

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and Eurasian landmass resulting in stronger ISM during MWP. Westerlies brought less rain

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during the MWP period, and the Westerlies rainfall strengthened significantly in the western Himalayas during the LIA. The mechanism proposed is that the western disturbances are

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intensified over NW India by the intensification of the Asian westerly jet stream over the Middle

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East during positive phase of a North Atlantic Oscillation (NAO) and intensification of the Asian

2009).

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jet to the lower latitudes during the warm phase of El Nino-Southern Oscillation (ENSO; Yadav,

Emphasis is being placed on an urgent need for accurate reconstruction of the former

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extent of glaciers in the Himalayan region during the Quaternary as the same would provide valuable data for palaeoenvironmental modelling (Owen et al., 1997; Zheng, 1989). However, it is further observed that the glacial chronologies bracket the major phases of climatic events (Barnard et al., 2004; Owen, 2009; Ali and Juyal, 2013; Bali et al., 2013) as other geological proxies for climate change are sparse (Mayewski et al., 2004). This is the reason that compilation of data for rapid climatic change during the Holocene shows major gaps in the Himalayan region. Although the paucity in palaeoclimatic data is particularly because of lack of the logistics and harsh terrain as well as weather (Owen, 2009; Bali and Srivastava, 2010), during the recent past some good results have been generated. Glacial deposits are considered to be valuable indicators of the past environment, nonetheless palaeoclimatic interpretation based 4

ACCEPTED MANUSCRIPT on moraines is subject to major temporal and spatial gaps. The proglacial lakes on the other hand preserve a relatively more continuous record of past climatic changes. The present study has

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been carried out on lateral basinal lake sediments in the Triloknath glacier valley of Lahaul

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Himalaya. The study area is lying in the transition zone of the ISM-dominated south and the

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MLW-dominated north and northwest Himalaya.

The number of multiproxy parameters including palynology, environmental magnetic, dendrochronology, isotope analysis, and geochemistry, etc., have been recently used to infer the

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Holocene climatic record of the Himalaya (Gupta and Khandelwal, 1982; Chauhan and Sharma,

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1996; Chauhan et al., 1997; Kotlia et al., 1997, 2010; Owen and Lehmkuhl, 2000; Phadtare 2000; Singh and Yadav, 2005; Yadav, 2011; Bali et al., 2015; Rawat et al., 2015a, 2015b). The

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present study also aims at understanding the pattern of climate changes in and around the

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Triloknath glacier valley located in the Lahaul Himalaya using sedimentological, geochemical,

2. Study Area

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and environmental magnetic parameters.

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Triloknath glacier is a ~6.5 km long, northeasterly flowing valley glacier located between 32º39'25.51" N to 32º36´19.57" N latitude and 76 º39'32.71"E to 76 º36'09.14" E longitude, in the fifth-order south Chenab basin, falling in the Lahaul district of Himachal Pradesh, India (Fig. 1A). Two mountain ranges, Pir Panjal and the Great Himalaya, develop the NW-SE orography with peaks more than 6000 m of altitude dividing the Lahaul valley with the frontal monsoon fed Himalaya. Landscapes formed during the Quaternary have been shaped mostly by glacial and fluvial activities (Owen et al., 1996; Adams et al., 2009). Triloknath glacier valley is presently occupied by two tributary glaciers that were joined at ~3900 m asl until the recent past (Swaroop et al., 2001). These glaciers receive dominant nourishment through snow/ice avalanches. Geologically, the study area is constituted of metasediments and is disposed closely north of the 5

ACCEPTED MANUSCRIPT Rohtang Gneissic Complex (Islam and Gururajan, 1997). The lithology in the area includes schists, phyllites, shales, quartzite, and related metasediments. The contour map of the area

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drawn using the ASTER data shows the distribution of various geomorphic features, including

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with the Chandrabhaga/Chenab river in the study area (Fig. 1B).

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the moraines, present-day snout position of the glacier, the location of the excavated pit along

In the Lahaul valley, climate varies in terms of altitude and geographic location with a strong N-S precipitation gradient varying from the monsoonal southern slopes of the Himalaya.

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Lahaul is particularly an important region located at an altitude of ~3500-5000 m asl as it marks

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the junction between the monsoon-influenced southern flank of Pir Panjal and the Greater Himalaya. Therefore, Lahaul is sensitive to the fluctuations of the ISM within the Himalayas

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(Owen et al,. 1997). During the time of reduced monsoons, the moisture is hardly able to

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penetrate in this part of the region (Owen, 2009; Wulf et al., 2010). The general climate of the area is predominantly dry as it is located in the rain shadow

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zone of the Himalayan region. The maximum temperature ranges between 7°C and 23°C and the minimum temperature ranges from -10°C to 10°C in the months of July and February,

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respectively. Snowfall begins in December, and it remains on the ground until the end of April. The western disturbances during the winter season cause solid precipitation, mainly up to 6 m and even more on the higher altitudes (CGWB, 2014). A large part of the mountains remain covered with perpetuating snow during most of the year, except during the brief spell of the rainy season when the ice in the lower elevation melts out. Cloudy days in one year account for merely 60 days. Owing to the high elevation of the area, the vegetation is scanty. Rainfall in the region is insufficient, and it varies between 100 and 400 mm annually (CGWB, 2007).

3. Methodology 6

ACCEPTED MANUSCRIPT 3.1.

Sample collection After carrying out a systematic geomorphological investigation of the area, a palaeolake

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site (Figs. 2 A,B) was discovered between the right lateral moraine and the valley wall (lateral

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basinal lake) of the Triloknath valley (Lat. 32º39'57'' N, Long. 76º40'29'' E). A 2.13-m-deep

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trench was excavated at the site. The lithological details of the trench profile are shown in Fig. 3. A closer view of the sediment profile reveals that the site is largely characterised by varying

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proportions of sand-, silt- and clay sized sediments. It is observed that from base up to 153 cm depth, a continuous 60-cm sequence of subangular cobble, pebble-rich, matrix-supported layer is

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present. This is followed by alternate bands of the medium sandy layer, sandy/silty layer, silty/clayey layer with specks of peat, and clay and silty layers. Prominent peaty layers of

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appreciable thickness are located at 21, 30, 77 and 90 cm depth (Fig. 3). Further trenching below

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213 cm was not possible because of the presence of large boulders. Samples weighing about 500 g each were collected at an interval of 3 cm for multiproxy analysis. Two samples for OSL

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dating and two bulk samples from organically rich horizons were collected for AMS 14C dating. For the environmental magnetic analysis, samples were collected at 2-cm regular intervals in 2

3.2.

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cm3 nonmagnetic plastic containers throughout the upper 153-cm sediment profile. Chronology

The chronology of the pit was established by OSL dates obtained from Physical Research Laboratory (PRL), Ahmadabad, India, and by AMS 14C dates from Beta Analytical Inc, USA. A total of four samples (two each for OSL and AMS

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C) were collected and dated. The OSL

samples were collected in 4-cm diameter stainless steel pipes from medium sand to silty layer at a depth of 150 cm (OSL-1) and 55 cm (OSL-3). The AMS from the peat layers located at 18 and 90 cm depths (Fig. 3).

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14

C dating samples were collected

ACCEPTED MANUSCRIPT The optical dating of the samples was carried out on quartz grains. Samples were sequentially pretreated in the laboratory with 1N HCl and 30% H2O2 to remove carbonates and

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organic matter respectively and then oven dried and sieved to obtain the 150−210 µm grain size

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fraction. Extracting of pure quartz from the pretreated sample was done by using a Frantz

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magnetic separator followed by 40% HF etching for 80 minutes and a 12N HCl treatment for 30 minutes. Optical measurements were made using an automated Risø TL-OSL-DA-20 reader (Bøtter-Jensen et al., 2010). The samples were stimulated using a blue diode (470 ±20 nm) and

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detection optics comprises an EMI 9835QA photomultiplier tube coupled with a 7.5-mm Hoya

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U-340 filter (emission 330 ±35 nm). Beta irradiations were carried out using an on-plate 90Sr/90Y beta source. The elemental concentrations of uranium, thorium, and potassium for environmental

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dose rate estimation were carried out using the high purity Germanium detector (model No.

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GC2518, Canberra, Australia). The errors of elemental measurement, systematic and statistical uncertainties, are <5% (Shukla et al., 2002). An average water content of 10 ±5 % was used, and

(1994).

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cosmic ray contributions to dose rates were calculated using the method of Prescott and Hutton

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The equivalent doses (De) were measured using a modified single aliquot regeneration (SAR) protocol (Murray and Wintle, 2000; Banerjee et al., 2001) with preheat of 240°C for 10 s and cut heat of 200°C. Dose growth curves were constructed using five regeneration dose points, including one point to estimate the recuperation and another point to estimate the reliability of the sensitivity correction (recycling ratio). Only those aliquots in which recycling ratios were within 10% of unity were considered for age estimation. Because over dispersion of De values in the present case is <25%, we used the central age model (CAM) for the computation of ages (Galbraith et al., 2005; Jacobs et al., 2006, 2008; Arnold and Roberts, 2009). 3.2.1. Age depth model

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ACCEPTED MANUSCRIPT All these dates were interpolated using statistical techniques to reconstruct the chronological framework for the whole samples collected at different heights from the vertical

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pit profile. The linear regression method of age–depth model, created on the basis of four

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available chronologies, shows three trends of sediment accumulation. The coefficient of

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determination shows strong linear correlation (R2 = 0.95). The above ages have been taken into account to calculate sedimentation rates at different depths (Fig. 4). For the lower part of the pit, the OSL age 6300 ±400 yr BP at 150 cm depth and AMS age of 2430 ±30 yr BP at 89 cm depth

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have been used, and the sediment accumulation rate for the horizon is 63.4 yr/cm. For the middle

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part, the AMS dates 2430 ±30 yr BP at 89 cm depth and OSL age of 2300 ±20 yr BP at 57 cm depth have been considered, and for this horizon the sedimentation rate is 4.06 yr/cm. For the

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upper part, the solitary AMS date 890 ±30 yr BP at 18 cm depth has been considered, and after

Grain size analysis

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3.3.

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extrapolating the age up to the surface, the sedimentation rate is 36.15 yr/cm.

Grain size is the most fundamental physical property of the sediment. It is effectively

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used to analyze the surface process and dynamic conditions of transportation and deposition and energy level of the depositional environment (Reineck and Singh, 1980). Climate controls the energy level of the depositional environment of a lacustrine deposit, thus the granulometric analysis of a sediment profile provides useful information about the climate existing at the time of deposition. The sediment grain size studies have been carried out to analyse the dynamics of the sedimentary environment (Singh and Singh, 2005). The present analysis has been carried out using a Laser Particle Size Analyzer (LPSA Cilas 1190) in the Centre of Advanced Study in Geology, University of Lucknow, Lucknow, India. The percentages of sand, silt, and clay have

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ACCEPTED MANUSCRIPT been plotted against depth and age (Fig. 5). A total of 51 samples from the top to a depth of 153 cm, collected at a regular interval of 3 cm, have been subjected to sediment grain analysis. Environmental magnetism

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3.4.

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Environmental magnetism links the magnetic properties of mineral assemblages to the environmental process. Environmental changes, including climate, that occur over variable time scales can influence the mode of sediment transport, deposition, and digenetic reactions (Liu et

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al., 2012, and references therein). The environmental magnetic parameters therefore have control over characteristics of the depositional setting because of the ubiquitous presence of iron oxides

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in sediments and their sensitivity to climate which can be measured using well established methods (Thompson et al., 1980; Thompson and Oldfield, 1986; Oldfield, 1991; Verosub and

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Roberts, 1995; Dekkers, 1997; Maher and Thompson, 1999; Evans and Heller, 2003; Sangode et

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al., 2007). The oxides of iron are sensitive to climate with a short response time and once

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produced can preserve stable records over longer geological times. The qualitative and quantitative estimates of iron minerals have been carried out using environmental magnetic methods, which also allows discrimination and quantification of

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different modes of authigenic and detrital iron oxides. The estimation of inherent mineral characteristics in response to a variety of magnetic fields of known direction and intensity is the basis for environmental magnetism. Weakly magnetic sediment samples are also analysed and characterized suitably by amplification using the high intensity magnetic fields (Thompson and Oldfield, 1986; Collinson, 1987; Dunlop and Ozdemir 1997; Maher and Thompson, 1999; Evans and Heller, 2003). The mineral magnetic parameters that are observed depend on the size, shape, and concentration of these minerals. Ratios of different magnetic properties are specific to grain size (domain size), mineralogy, and/or concentration; whereas, coercive force distributions can be used to discriminate between different magnetic minerals (Robertson and France, 1994; 10

ACCEPTED MANUSCRIPT Kruiver et al., 2001). These techniques are rapid, nondestructive, grain size sensitive and allow analysis without physical separation. Also, a large number of samples can be analysed within a

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short time.

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The magnetic parameters commonly used for inferring the palaeoclimatic changes

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include low field magnetic susceptibility (lf) and its frequency dependency (fd), anhysteretic remanent magnetisation (ARM) and its susceptibility, isothermal remanent magnetisation (IRM) and their derivatives and ratios (Dekkers, 1997; Evans and Heller, 2003; Peters and Dekkers,

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2003).

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The environmental magnetic studies were conducted at Rock Magnetic Laboratory of Department of Geology, Savitribai Phule Pune University, Pune, by measuring a total of 75 samples from the top to a depth of 153 cm. The samples were air dried and tightly packed into 2

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cm3 nonmagnetic cubes for analysis. The magnetic susceptibility (κ) was measured using a Bartington MS-2B laboratory sensor in 0.465 kHz low frequency and 4.65 kHz high frequency.

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The κ values were mass normalised and then represented as χ. Low field magnetic susceptibility (lf) is one of the most fundamental and widely used parameters at room temperature that

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provides bulk estimation for ferrimagnetic concentration (e.g., magnetite-titanomagnetites and maghemite). The susceptibility can also reflect the effects of weak antiferromagnetism or the dilution because of negative susceptibilities from many diamagnetic minerals. It is also an important discriminative parameter when used as a ratio with other hysteresis parameters for the entire sampled profile (Thompson and Mortan, 1979; Dearing, 1999; Liu et al., 2012). The ARM was developed by placing the samples in known alternating fields with a small superimposed biased field using an Agico alternating field demagnetizer and the remanence was measured using a Minispin fluxgate spinner magnetometer. The ARM is normalized by the bias field to express the susceptibility of ARM (ARM). The IRM was produced by inducing forward magnetic fields of 25, 50, 100, 300, 500, 800, 1000, 1200, 1500, and 2000 mT in an Impulse 11

ACCEPTED MANUSCRIPT magnetizer and measured using a Minispin fluxgate spinner magnetometer. Further, the back fields of -10, -20, -50, -75, -100, and -300 mT were applied to demagnetize the samples. The

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IRM spectra for each sample were further used to analyse various parameters including

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saturation and coercivity. Finally, various standard ratios and parameters were calculated (e.g.,

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fd, B(0)CR, S-Ratio, SIRM/χlf, HIRM, SoftIRM, χARM/SIRM, and χARM/χlf) to estimate the qualitative and semiquantitative information from the studied profile (Liu et al., 2012). Saturation isothermal remanence magnetization (SIRM) reveals the magnetic mineral

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concentration when the magnetic grain size and the mineralogy remain relatively constant

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(Peters and Dekkers, 2003). During the present analysis, the majority of SIRM has been observed to be achieved below IRM2000mT (SIRM = IRM2000mT). All ferrimagnetic mineral was

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saturated well below IRM300mT, whereas antiferromagnetic minerals might have required higher

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fields for saturation (France and Oldfield, 2000; Rochette et al., 2005). Hard isothermal remanent magnetization (HIRM = SIRM + IRM-300mT/2) and soft isothermal remanent

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magnetization (Soft IRM = SIRM - IRM20mT)/2) have been analyzed for the estimation of antiferromagnetic minerals (hematite and goethite) and ferrimagnetic minerals (magnetites and

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maghemites) respectively (Thompson and Oldfield, 1986; Evans and Heller, 2003; Liu et al., 2007, 2012; Lyons et al., 2010). The coercivity of isothermal remanent magnetization (B0(CR)) has been computed after reversing the applied field to reduce the SIRM to zero (Thompson et al., 1980). It is an important parameter that helps in distinguishing amongst the ferrimagnetic and antiferromagnetic assemblages and their granulometric relation (Dunlop and Ozdemir, 1997). The ferrimagnetic multidomain (MD) grains (˃15 µm) generally show very low B0(CR) (˂20mT), whereas the ferrimagnetic single domain (SD) grains (˂0.03 µm) depict B0(CR) values in the range of 20–50 mT. The canted antiferromagnetic mineral hematite shows B0(CR) values > 100 mT, and very high values are shown by goethite (Sangode, et al., 2007, Liu et al, 2012). The S-ratio is defined 12

ACCEPTED MANUSCRIPT as S = (IRM_0.3T/SIRM) (King and Channel, 1991). The S-ratio is a measure of the relative abundance of high-coercivity minerals in a mixture with ferrimagnetic minerals (e.g., magnetite

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and maghemite). When ferrimagnetic minerals are dominant, S-ratio approaches unity. However,

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when the concentration of hematite/goethite increases, S-ratio decreases gradually. When 100

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mT backfield is applied, high negative S-ratios (IRM-0.1T S M˃ 0.75) are indicative of MD ferrimagnetic particles followed by less negative ratios (~ 0. 5 to

0.5) for SD–PSD grains.

Very low S-ratios approaching zero indicate admixtures of ferrimagnetic and antiferromagnetic

to stoichiometric substitution and magnetocrystalline anisotropy within

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are related

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oxides. The positive values (0 to 0.3) indicate pure antiferromagnetic minerals and higher values

antiferromagnetic grains (Dekkers, 1997; Evans and Heller, 2003; Peters and Dekkers, 2003). The ratios SIRM/χlf, χARM/SIRM, and χARM/χlf have also been calculated to distinguish amongst

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the magnetic grain size (domain size). The χARM/SIRM is a grain-size-dependent ratio sensitive to the particles that carry stable magnetisation, i.e., those with SD and PSD grain sizes

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(Snowball, 1991; Roberts and Turner, 1993; Roberts, 1995). The χARM is sensitive to the concentration of SD grain size, therefore normalising it with concentration parameter χlf can be

3.5.

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used for relative variation of the concentration of SD grains (Maher, 1988).

Geochemical analysis X-ray fluorescence (XRF) spectrometry was used to determine the major and trace

element chemistry of sediment samples (see supplementary Table 1). The analysis of the sediment samples was done on a WD-XRF make of PANalytical, Axios. The pressed sample pellets were made using movial solution as binder (for details see Watson, 1996; Takahashi, 2015). Samples collected from the field, as discussed in section 3.1, were air dried and crushed to -200 mesh grain. Sample processing for chemical analysis by WD-XRF was kept the same for standards and samples for any particular set of analysis (Tripathi et al., 2007). During the major 13

ACCEPTED MANUSCRIPT and trace elements analysis, international rock standards were run as unknown after the calibration of the instrument with international standards (BHVO-2, MBH, GSP-2, SDC, SDO,

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SCO, MAG) to check the precision of the given set of analysis. The total volatile content of the

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sediment samples was determined by ignition at 1000ºC and is expressed as ‘loss on ignition’

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(Lechler and Desilets, 1987). The precision of the analysis was better than 10% for major and 5% for trace elements analysis.

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The degree of chemical weathering of rocks and sediments was obtained from the major elements geochemical data. The Chemical Index of Alteration (CIA; Nesbitt and Young, 1982)

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calculated using the following formula:

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is an important geochemical tool to understand the extent of weathering and its trend. The CIA is

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where CaO* represents the CaO in the silicate fraction only. The geochemical data are also used to know the weathering trend of rocks containing aluminosilicate minerals using the A-CN-K diagram (Nesbitt and Young, 1984, 1989). The weathering trend of lake sediments has been

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displayed on an A-CN-K (Al2O3-‘CaO*+Na2O’-K2O) triangular plot (Fig. 6).

4.

Results The Triloknath glacial-palaeolake formed within the right lateral moraine, and the valley

wall received the sediments from the surrounding area under different climatic conditions. The basal 60-cm unit comprised of subangular, matrix-supported till layers is exposed from 213 up to 153 cm depth of the profile. This is followed by a silty layer, silty sandy layer, gritty/sandy layer, and silty layers with peat at different intervals (Fig. 5). The textural analysis of the sediment profile reveals that the lithology is basically silt dominated. The percentage of the silt 14

ACCEPTED MANUSCRIPT is maximum (87.2%) at a depth of 6 cm, and minimum (59.5%) at a depth of 114 cm. The fraction of sand is maximum of 32.4% at a depth of 114 cm and is absent at 90, 93, and 144 cm

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in the profile. The clay percent is maximum (17.0%) at 36 cm and minimum (8.0%) of 114 cm.

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The mean grain size varies from 3φ to φ, i.e., from very fine sand to fine silt. The dominance of

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silt fraction indicates the low energy condition at the depositional site. The silt percentage varying from 59.5 to 86.6 indicates the consistent sedimentary environments with some fluctuations as indicated by the increasing and decreasing percentage of sand and clay. The

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increasing percent of the silt and sand is possibly governed by the detrital influx as a result of

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enhanced precipitation / energy conditions. On the other hand, the higher clay fraction and low silt indicates low influx from the surrounding area, suggesting a stagnant ponding environment

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under lower energy conditions. The XRD analysis of the sediment samples mainly indicated the

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presence of quartz, K-feldspar, biotite, and chlorite minerals (unpublished data). Based on the variability of environmental magnetic parameters, the 153-cm profile has

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been subdivided into five zones from the bottom (zone I) up to the top (zone V; Fig. 7). Each of these zones appears to have been governed by changes in depositional environments in response

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to the changes in the Triloknath glacial conditions. The low χlf (mean: 1.33 x 10-8 m3/kg, median: 1.35, minimum: 0.9, and maximum: 1.66) depicts a low ferrimagnetic concentration for the entire sampled profile. The low standard deviation as well as close distance between mean and median values infer a unimodal source besides its low variability. This low variability in the lithogenic parameters therefore is conducive to recording the climogenic signatures witnessed by the Triloknath glacial system. The weak susceptibilities do not permit the use of frequency dependency, which is within the instrumental noise. In this instance, we used only the high values (>5%), carefully considering the relatively higher susceptibilities and the trend lines. The low values of SIRM further endorse 15

ACCEPTED MANUSCRIPT the lower concentration of ferrimagnetic composition with low variability. The mean value of Sratio(-0.1T) of ~-0.3 with variability between -0.5 and 0.02 depicts single domain (SD) to pseudo

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single domain (PSD) ferrimagnetic mineralogy with admixtures of antiferromagnetic minerals in

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places. The mean coercivity of remanence (B(0)CR) of 47 mT within a range from 36 to 110 mT

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indicates a majority of SD (hard) ferrimagnets with the presence of antiferromagnetic (hematite bearing) mineralogy in some horizons. The other parameters like SIRM/χLF, HIRM, and Soft-

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IRM substantiate the above inferences.

Positive correlation of χARM with χlf indicates that the bulk concentration and hence

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susceptibility is controlled by the stable SD ferrimagnetic grains. Further, the significant positive correlation between χARM and SIRM substantiate the above inferences. The significant positive

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correlation amongst SIRM, χARM, soft-IRM, and their ratios indicates variability within the SD-

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PSD ferrimagnetic range.

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We have observed that the gross variation in mineral magnetic parameters is largely independent of lithologic variability (see Fig. 7). The parameters thus appear to be faithful to magnetic mineral control of the depositional environments favoured by the regional glaciogenic

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climatic regimes. With a small internal fluctuation, the magnetic susceptibilities show a bellshaped curve at a depth of 111 cm from the top (marked as zone I in Fig. 7). The SIRM shows a similar trend to that of χlf in this zone with small fluctuations in SIRM/χlf. The coercivity of remanence (B(0)CR), however, does not coincide with the lithologic boundary and remains notably constant across the boundary, clearly indicating no change in mineralogy. This bellshaped curve therefore indicates the gradual change in concentration rather than mineralogy in zone I. The B(0)CR and S-ratio on the other hand show a peak at 143 cm, depicting the change in mineral composition. The value of ~80 mT for B(0)CR and near-zero values for S-ratio indicate a mixed mineralogy of possibly SD ferrimagnetic with traces of antiferromagnetic minerals. In 16

ACCEPTED MANUSCRIPT this glacial lake system, such conditions may arise from a warmer episode within a cold regime. The antiferromagnetic component (hematite) therefore suggests a brief warm climate episode at

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this interval with a peak at 143 cm. Further, during 111 to 71 cm, an apparent increase in

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ferrimagnetic concentration followed by two peaks of antiferromagnetic mineralogy at 85 and 71

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cm within the ferrimagnetically dominating mineralogy, is noticed. The finer ferrimagnetic grain size (majority of stable SD) depicts the ponding nature of the depositional environment with low detrital influx. The SD-dominating mineralogy suggests less oxidative nature with the two peaks

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of change at 85 and 71 cm as noted above, indicative of a warmer episode. Excessive melting

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because of warming would raise the lake levels resulting in less oxygenated bottom waters at the depositional site. This zone from 111 to 71 cm is therefore depicted as zone II. Farther upward,

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gritty sandstone appears in the lithology, although the mineral magnetic parameters do not show

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any notable change. After 71 cm, significant changes in mineralogy mark the beginning of zone III. This zone also shows very little change in mineralogy except by an increase in the χfd%

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corresponding to the clay-rich facies suggesting pedogenic environments. This pedogenic phase may be attributed to the catchment stability because of low sediment flux. However the B(0)CR

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and S-ratio do not indicate any significant change in mineralogy (such as warmer conditions), and the climate remains unaltered till the end of this zone. Further, zone IV is noticed for the change in mineralogy toward a more antiferromagnetic nature depicting a major warm episode. This is followed by zone V with a similar warm episode. Zones IV and V indicate pedogenic enhancement under warmer climate (reflected from Xfd%, B(0)CR, S-ratio, and IRMafm). Thus, the studied profile records an overall cold climate regime with the small warm episode at 143 cm, followed by cold conditions until 71 cm. Zone III again shows a cold climate with pedogenic stability in the catchment. Zones IV and V show two major warming episodes changing the regional glacial regime. 17

ACCEPTED MANUSCRIPT Geochemical analysis of the sediment record shows that the sediments of the lake were sourced from an average granite-granodiorite rock composition (Fig. 6). The lithology in the

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area includes schists, phyllites, shales, quartzite, and related metasediments. Their erosion from

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the catchment and then their mixing before their deposition can give rise to an average upper

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crustal rock composition.

The CIA values of lake sediments and its trend on the A-CN-K and A-CNK-FM

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triangular plots (Fig. 6) have been used to understand the intensity and nature of weathering in the area and corresponding changes in sediment chemistry with time as recorded in the lake

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sediment section. We have found that the CIA of all the samples ranges between 69 and 73 (Fig. 8). They plot together in the A-CN-K diagram but stretched to a limited extent on the weathering

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trend along the A-CN line. The CIA and its trend in the A-CN-K diagram signify that the

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samples are very less to moderately weathered, and they have not undergone any major postdepositional change (such as K enrichment; Fedo et al., 1995). Therefore, from the weathering

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trend, we found that sediments were sourced from an average granite-granodiorite lithology. The presence of rock types of schists, phyllites, and shales in the catchment indicate that the present

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value of CIA of the sediments was inherited from the original initial CIA of the source as well as the limited extent of weathering in the catchment. The source rock may already have some initial higher CIA values.

As far as the elemental changes through the depth of the lake are concerned, we have grouped the geochemical data, based on their trends (see supplementary Table 1) into two sets: the first set includes Ti, Al, Fe, Mg, Ba, V, Cr, Co, Ni, Cu, Zn, and Rb; while the second set has Si, Ca, Na, K, Sr, Zr, and Mo. Elements within one set mostly behave synchronously, except for the divergences in the patterns in zone V, which indicates more complex environmental conditions (Fig. 8) after 890 ±30 yr BP. 18

ACCEPTED MANUSCRIPT 5.

Discussion High resolution magnetic, geochemical, and sediment textural studies on the palaeolake

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profile have been used as a major tool to understand the late Quaternary climatic changes. Study

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of various parameters (Fig. 7) led us to assign major zones of variability based on the

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concentration and distribution of the magnetic minerals, relative proportion of the ferrimagnetic and antiferromagnetic minerals, magnetic grain size (domain size), nature of detrital influx, the

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presence of pedogenic environments, and oxidising or reducing conditions. We have demonstrated that the ferri- and antiferromagnetic mineral assemblages in different

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concentrations at various depths/age help in inferring diverse environmental conditions controlling their genesis, transportation, and deposition (Rawat et al., 2015b).

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The geochemical data helped us to understand the composition of source lithology,

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distribution of primary and secondary minerals, weathering status (index) of sediments, and weathering trend through time, using the A-CN-K diagram (Nesbitt and Young, 1984,

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1989; Fedo et al., 1995; Azam and Tripathi, 2016). The major and trace element distribution through time in the lake sediments also helps to understand biogeochemistry of the lake and

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depositional conditions (Azam and Tripathi, 2016, and references therein). The systematic sampling enabled closely spaced environmental magnetic data for the palaeolacustrine profile located almost 1.5 km downstream of the present day snout in the Triloknath glacier valley to reconstruct five first-order climatic zones. Based on limited chronology, ages have been extrapolated for the pit profile. The study has revealed different environmental conditions and variation in mineral magnetic parameters largely independent of lithologic variability from ~6824 cal. YBP to present (Fig. 4), whereas variation in the geochemical composition has been used to decipher environmental conditions experienced in the lake catchment. 19

ACCEPTED MANUSCRIPT The Lahaul Himalaya has recorded two phases of cold events at ~8.8 to 8.1 ka BP and ~7.4 to 6.7 ka BP with an intermittent warm and moist climate (Rawat et al., 2015a). Very likely

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the 60 cm of coarser angular glacial till sediments encountered at the base of the pit profile from

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213 to 153 cm depth represents the morainic material over which the ponding was initiated at

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around 6484 cal. YBP. Alternatively, if the lake existed during this time, the sediments were deposited during the cold event when the lake must have been shrunk under a frozen state and the hillslope debris must have provided the coarser material. Close examination of the profile

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suggests the presence of erosional contact at this junction, indicating that the surface was

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exposed to weathering. This was followed by the deposition of alternating layers of clay, silt, and sand under moderate energy conditions during ~6300 cal. YBP. Initially, the higher

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percentage of silt seems to be because of the influx of sediments from adjoining areas during

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enhanced precipitation. Further, the lower percentage of silt but a higher percentage of sand explains the continuation of the enhanced precipitation with some fluctuations. Based on the

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palynological studies of the Tso kar lake lying to the north of the present area of investigation, Demske et al. (2009) suggested a weaker summer monsoon and the accompanying enhancement

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of the winter westerly flow from ca. 9.2 to 4.8 ky BP. This possibly resulted in the winter precipitation of snow that led to freezing conditions of the Triloknath lake. Wunnemann et. al. (2010) suggested a major rise of the Tso kar lake at around 7.0 ka BP in response to increased glacial melt. A similar expansion of lake and enhanced melting resulted in the subsequent deposition of the relatively finer sediments post ~6484 cal. YBP in zone I. Climatic zone I, demarcated between ~6484 and 3904 cal. YBP, shows an initial maximum influx of magnetic minerals. A conspicuous increase in antiferromagnetic minerals, including the appearance of hematite during ~5925 cal. YBP to 5676 cal. YBP has been observed. The high CIA values in zone I support an erosion limited condition (Fig. 8). Therefore, a warm and wet climate with increased ISM intensity seems to be very likely for the 20

ACCEPTED MANUSCRIPT basal part of zone I, which corresponds to the mid-Holocene warming. This is further supported by the presence of broad-leaved birch (Betula) forests along with Quercus, Corylus, Carpinus,

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Rhododendron, etc. between ~6300 and 5379 cal. YBP (Bali et al., 2016). Other workers

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(Bhattacharyya, 1988; Phadtare, 2000; Demske et al., 2009; Trivedi and Chauhan, 2009; Rawat

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et al., 2015a,b) have reported mid-Holocene climatic warming in other Himalayan basins between ~6000 and 4500 cal. YBP. However, in the same zone, a decrease in ferrimagnetic and antiferromagnetic mineral concentration from ~5426 and 3904 cal. YBP, suggests a reduced

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monsoon season with less warm climatic conditions as compared to the earlier period. The CIA

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shows a decreasing trend until the transition phase of zone I - zone II. The decrease in CIA values is indicative of the supply of less weathered material from the provenance, which was

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because of the changing phase toward colder and dryer conditions. This decreasing weathering

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trend of CIA has been supported by the decreasing trend of set I elements and the increasing trend of Si, Na, K, Ca, and Sr of set II elements. Reduction in ISM precipitation has been

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reported during this period widely in terrestrial and marine sediments (Phadtare, 2000; Chauhan, 2003; Sharma et al., 2004; Demske et al., 2009; Leipe et al., 2013). Reduction in magnetic

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mineral concentration between ~5770 and 3172 cal. YBP has also been reported from the Chandra Pit bog (Rawat et al., 2015b) suggesting a decrease in ISM and a less warm climate as compared to the early Holocene. The reduced moisture supply post 6 ky BP seems to be associated with a general decrease in monsoon activity as a result of a decrease in summer insolation and a continuous southward retreat the of Inter-Tropical Convergence Zone (ITCZ; Fleitmann et al., 2007; Demske et al., 2009). Also in zone II, during ~3904 to 2365 cal. YBP, the presence of two peaks of antiferromagnetic minerals (hematite) suggests brief warmer episodes during ~2421 and 2361 cal. YBP within overall cold conditions (Fig. 7). The finer ferrimagnetic grain size (SD) and low energy environments depict enhanced ponding conditions resulting from high lake levels 21

ACCEPTED MANUSCRIPT because of excessive melting. The SD ferromagnetic dominating mineralogy suggests a less oxidative nature with two peaks during the same period. After 111 cm corresponding to around

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3900 cal. YBP, the percentage of sand suddenly lessens (from 22.82% to 0%) with a

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corresponding increase in the percentage of silt (between 77.25 and 85.77 %). This too is

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suggestive of a low influx of sediments at the site because of high lake levels. Further, the higher clay percent, ranging from 10.02% to 16.23%, supports the low energy stagnant ponding conditions. The magnetic and the corresponding pollen data suggest cold conditions and high

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snow precipitation. The pollen data (Bali et al., 2016) suggest that during this time frame the

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area had less diversification of herbaceous taxa, the spread of conifers, and reduction in broad leaved elements implying cold conditions and reduced SW monsoon. As indicated by the

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weathering trend (Fig. 8), zone II (although initially having cold conditions) turned towards a

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humid phase by 2430 yr BP. During this phase Ca, Na, and Sr show a decreasing trend supporting the CIA trend. However, K along with set I elements show an increasing trend. The

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affinity of K with Ti, Mg, Fe, and Ba supports an increased contribution of biotite and other clay minerals from the source region. From the CIA excursion, we found that the end of zone II was

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supported by cold, dry conditions.

Zone III, representing a time span between ~2365 and 1758 cal. YBP, shows very little change in mineralogy except for an increase in the Xfd% corresponding to the clay-rich facies, suggesting pedogenic enhancement. From the CIA excursion, we can infer that this zone was initiated with a warm and humid phase. This pedogenic phase may be attributed to the catchment stability because of low sediment flux. The B(0)CR and S-ratio do not indicate any significant change in mineralogy (such as warmer conditions) and the climate remains unaltered until the end of this zone. The textural data suggest a relatively higher percentage of sand and clay (max. 23.83 and 15.90% respectively) with moderate amounts of silt (66.04 to 84.16%). The variation 22

ACCEPTED MANUSCRIPT in grain size is indicative of episodic rain with the fluctuating climate in the region. Weak SW monsoons have been reported from the Chandra valley during ~2032 and 1158 cal. YBP (Rawat

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et al., 2015a, b) as well as from the Ganga plain between 3200 and 1200 cal. yr BP (Trivedi et

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al., 2013). Reduction in the monsoonal precipitation and a prevalence of dry climate around 2 ky

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BP has also been recorded in the Kinnaur Himalaya (Chakraborty et al., 2006). Prasad et al. (2014) suggested that ENSO and the shifts in the position of the Indo-Pacific Warm Pool (IPWP) were responsible for the prolonged droughts during 2.0-0.6 cal yr BP in central India.

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This seems to have caused a reduction in intensity of the SW monsoon in the Himalayan region

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as well.

Further, zone IV (corresponding to ~1758 to 1107 cal. YBP) and zone V (representing a

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time span from ~1107 cal. YBP to present) represent an increase in the concentration of

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magnetic minerals as a result of a major warm episode with enhanced monsoonal precipitation. The magnetic parameters suggest mineralogical change toward an antiferromagnetic dominant

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phase, implying a major warm episode during ~742 to 593 cal. YBP. Pedogenic enhancement has been observed under warmer climatic condition reflected from χfd%, B

S-ratio, and

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IRMafm.

(0) CR,

The changes in weathering index indicate the presence of a cold, dry pulse around 2.3 ka BP, followed by a continuous increasing weathering trend through zones III and IV until around 890 yrs BP. Around this time, the CIA reached a higher range (Fig. 8), indicating very supportive weathering conditions (i.e., warmer and humid) in the catchment. The elements Ti, Fe, Mg, K, Ba, V, and Ni have been found in agreement with the CIA and enrichment in the supplied sediments to the lake. Maximum expansion of broad-leaved birch (Betula) forests and some coeval improvement of coniferous forests around 2228 to 962 cal. YBP suggest that a warm and humid climatic condition prevailed in the region owing to enhanced monsoon 23

ACCEPTED MANUSCRIPT precipitation (Bali et al., 2016). This event within zone V could be correlated with the Medieval warm conditions (A.D. 900 to 1300) encountered globally (Singh et al., 2015). The climate

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turned warm and more humid with the initiation of a more active SW monsoon as manifested by

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a further increase in broad-leaved birch (Betula) forests and a contemporary reduction of

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coniferous forests around 962 to 300 cal. YBP (Bali et al., 2016). The CIA values of the sediments also declined by around 300 cal. yrs BP, indicating less weathering in the catchment. This could be because of limited weathering conditions during the Little Ice Age; as a result, the

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sediments with lower CIA values were supplied to the lake. Since the LIA until present, the

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northern face of the orographic barrier in the western Himalaya receives precipitation dominantly during winter through westerlies (Benn and Owen, 1988; Wulf et al., 2010). This

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along with the present day weaker monsoon conditions (Bookhagen et al., 2005) seems to be the

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reason for the lake still receiving a less weathered sediment supply. Possibly, the short time range of 200-400 years has not been sufficient to produce weathered material in the lake

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catchment. We have observed that Ca and P show a good correlation through zone V, indicating availability of Ca-phosphate minerals such as apatite, through physical weathering in the

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catchment.

Other ISM-influenced Himalayan basins also have records of this warm and humid climate phase (Von Rad et al., 1999; Chauhan et al., 2000, 2010; Sarkar et al., 2000; Chauhan, 2006; Rawat et al., 2015a,b; Singh et al., 2015). Further, an overall decrease in χlf, SIRM, HIRM, and soft-IRM has been observed at ~300 cal. YBP (A.D. 1650) possibly representing colder climate prevailing during the LIA. Signatures of the LIA have also been found in Chandra valley (Rawat et al., 2015a) from ~852 to 239 cal. YBP along with other parts of the Himalaya (Bhattacharyya, 1988; Mazari et al., 1995; Chauhan et al., 2000, 2010).

24

ACCEPTED MANUSCRIPT 6.

Conclusions High resolution environmental magnetic, sedimentological, and geochemical studies

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based on systematic sampling of the 213-m Triloknath palaeolake profile has enabled the

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reconstruction of palaeoenvironmental conditions of the region since ~6484 cal. YBP. The

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present study seems to be significant as no such records of climatic reconstruction are available from this part of the Lahaul Himalaya. Lake building activity, very likely was initiated at ~6500

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cal. YBP and has subsequently been influenced by the climatic conditions, the ISM strength, and the western disturbances. An erosional contact observed at ~6484 cal.yrs. BP suggests surface

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exposure of the lake. During ~5925 to 5676 cal. YBP, an increase in antiferromagnetic content, marked by the appearance of hematite and increased CIA depicts a warm and wet climate with

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increased ISM intensity, very likely corresponding to the mid-Holocene warming. At ~2421 and

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~2361 cal. YBP, two warmer episodes have been observed within cold conditions, and the presence of a finer grain size and low energy conditions of the sedimentation depict the ponding

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nature of a deposition with a low detrital influx of sediments with higher CIA values. Between ~2365 and 1758 cal. YBP, clay-rich facies and an increasing trend of CIA suggest pedogenic

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enhancement and catchment stability, reflecting low sediment flux during a weaker ISM. Also except for around 300 cal YBP, during ~1758 cal. YBP to present, warm episodes with an enhanced monsoon as well as pedogenic enhancement have been observed. The decrease in temperature at ~300 cal. YBP (A.D. 1650) is likely to be influenced by the Little Ice Age. Since then, the sediments have shown a decrease in CIA because of weathering-limited cold conditions, likely under the influence of westerlies. Acknowledgements Authors are thankful to the Head, Centre of Advanced Study in Geology, University of Lucknow, Lucknow, and the Director, Birbal Sahni Institute of Palaeosciences, Lucknow, for 25

ACCEPTED MANUSCRIPT providing working facilities. JKT thanks Dean, School of Environmental Sciences, Jawaharlal Nehru University, for providing lab and analytical facility. RB thanks the Department of Science

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and Technology, Government of India, New Delhi, for funding the project (project no. SR/DGH-

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38/2012). SJS acknowledges the funding for the lab from DST, New Delhi grant SR/S4/ES-

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409/2009 and DST FIST grant SR/FST/ESII-101/2010 to the Department of Geology, SPPU. We also thank and acknowledge all the reviewers whose valuable suggestions have helped to

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improve the manuscript.

REFERENCES

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Adams, B., Dietsch, C., Owen, L.A., Caffe, M.W., Spotila, J., Haneberg, W.C., 2009. Exhumation and incision history of Lahaul Himalaya, northern India, based on (U/Th)/He

thermochronometry

and

terrestrial

cosmogenic

nuclide

methods.

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Geomorphology 107 (3), 285-299.

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Ali, N.S., Juyal, N., 2013. Chronology of late Quaternary glaciations in Indian Himalaya: a critical review. Jour. Geol. Soc. Ind. 82, 628-638.

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Ali, N.S., Biswas, R.H., Shukla, A.D., Juyal, N., 2013. Chronology and climatic implications of late Quaternary glaciations in the Goriganga valley, central Himalaya, India. Quat. Sci. Rev. 73, 59-76.

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Anderson, D. M., Overpeck, J. T., Gupta, A. K., 2002. Increase in the Asian southwest monsoon during the past four centuries. Science 297, 596–599. Arnold, L.J., Roberts, R.G., 2009. Stochastic modelling of multi-grain equivalent dose (De) distributions: implications for OSL dating of sediment mixtures. Quat. Geochronol. 4, 204-230. Azam, M.F., Wagnon, P., Vincent, C., Ramanathan, A.L. Favier, V., Mandal, A., Pottakkal, J.G., 2014. Processes governing the mass balance of Chhota Shigri Glacier (western Himalaya, India) assessed by point-scale surface energy balance measurements. The Cryosphere 8 (6), 2195-2217. Azam, M.F., Ramanathan, A. L., Wagnon, P., Vincent, C., Linda, A., Berthier, E., Sharma, P., Mandal, A., Angchuk,T., Singh, V.B. Pottakkal, J,G., 2016. Meteorological conditions, seasonal and annual mass balances of Chhota Shigri Glacier, western Himalaya, India. Ann. Glac. 57, 328 – 338. 26

ACCEPTED MANUSCRIPT Azam, M. F., Tripathi, J. K., 2016. Recent contributions in the field of sediment geochemistry. Proc. Ind. Nat. Sci. Acad. 82, 805-816. Bali, R. Srivastava, D., 2010. Urgent need to develop manpower for glaciological investigation.

T

Curr. Sci. 99 (9), 1159.

IP

Bali, R., Awasthi, D.D., Tiwari, N.K., 2003. Neotectonic control on the geomorphic evolution of the Gangotri Glacier Valley, Garhwal Himalaya, Gond. Res. 6 (4), 829-838.

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Bali, R., Agarwal, K. K., Ali, N.S., Rastogi, S.K., Krishna, K., Srivastava, P., 2013. Chronology of Late Quaternary Glaciation in the Pindar valley, Alaknanda Basin, Central Himalaya (India). Asian Jour. Ear. Sci. 66, 221-233.

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Bali, R., Nawaz, A. S., Bera, S. K., Patil, S. K., Agarwal, K. K., Nautiyal, C. M., 2015. Impact of Anthropocene vis-a-vis Holocene climatic changes on Central Indian Himalayan

MA

Glaciers. Springer Int. Pub. Switzerland G. Lollino (Ed.). In Eng. Geol. for Soc. and Territ. 1, 467- 471.

Bali, R., Chauhan, M.S., Mishra, A.K., Ali, N.S., Tomar, A. P., Khan. I., Singh, D.S.,

D

Srivastava, P., 2016. Vegetation and climatic changes in the temperate belt of Himachal

TE

Pradesh since 6300 CAL. Years BP, Inferred from pollen evidence of Triloknath palaeolucastrine deposit. Quat. Int. http://dx.doi.org/10.1016/j.quaint.2016.07.057.

CE P

Banerjee, D., Murray, A.S., Botter-Jensen, L., Lang, A., 2001. Equivalent dose estimation using a single aliquot of polymineralfine grains. Radiat. Meas. 33, 73-94. Barnard, P.L., Owen, L.A., Sharma, M.C., Finkel, R.C., 2004. Late Quaternary (Holocene) landscape evolution of a monsoon-influenced high Himalayan valley, Gori Ganga, Nanda

AC

Devi, NE Garhwal. Geomorphology. 61, 91-110. Benn, D.I., Owen, L.A., 1998. The role of the Indian summer monsoon and the mid latitude westerlies in Himalayan glaciation: review and speculative discussion. Jour. Geol. Soc. 155, 353-363. Bhattacharyya, A., 1988. Vegetation and climate during postglacial period in the vicinity of Rohtang Pass, Great Himalayan Range. Pollen Spores 30 (3-4), 417–427. Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., LottiBond, R., Hajdas, I., Bonani, G., 2001. Persistent solar influence on North Atlantic climate during the Holocene. Science 294, 2130-2136. Bookhagen, B., Rasmus, C.T., Strecker, M.R., 2005a. Abnormal monsoon years and their control on erosion and sediment flux in the high, arid northwest Himalaya. Ear. Plan. Sci. Lett. 231, 131–146. 27

ACCEPTED MANUSCRIPT Bookhagen, B., Thiede, R.C., Strecker, M.R., 2005b. Late Quaternary intensified monsoon phases control landscape evolution in the northwest Himalaya. Geology 33 (2), 149–152. Bookhagen, B., Fleitmann, D., Nishiizumi, K., Strecker, M.R., Thiede, R.C., 2006. Holocene

T

monsoonal dynamics and fluvial terrace formation in the northwest Himalaya, India:

IP

Geology 34, 601-604.

Bøtter-Jensen, L., Thomsen, K.J., Jain, M., 2010. Review of optically stimulated luminescence

SC R

(OSL) instrumental developments for retrospective dosimetry. Radiat. Meas. 45, 253257.

Central Ground Water Board, 2007. Ground Water Information Booklet Lahaul & Spiti District

NU

Himachal Pradesh. Northern Himalayan Region Dharmsala.

Central Ground Water Board, 2014. Ground Water Information Booklet Lahaul & Spiti District

MA

Himachal Pradesh. Northern Himalayan Region Dharmsala. Chakraborty, S., Bhattacharya, S.K., Ranhotra, P.S., Bhattacharyya, A., Bhushan, R., 2006. Palaeoclimatic scenario during Holocene around Sangla valley, Kinnaur northwest

D

Himalaya, based on multi proxy records. Curr. Sci. 91 (6), 777–782.

TE

Chauhan, M.S., 2006. Late Holocene vegetation and climate change in the alpine belt of Himachal Pradesh. Curr. Sci. 91 (11), 1562–1567.

CE P

Chauhan, M.S., Sharma, C., 1996. Pollen Analysis of Mid-Holocene Sediments from Kumaon Himalaya. Geol. Sur. Ind. Spec. Pub. 21, 257-269. Chauhan, M.S., Sharma, C., Rajagopalan, G., 1997. Vegetation and climate during LateHolocene in Garhwal Himalaya. Palaeobotanist 46, 211-216.

AC

Chauhan, M.S., Mazari, R.K., Rajagopalan, G., 2000. Vegetation and climate in upper Spiti region, Himachal Pradesh during late Holocene. Curr. Sci. 79, 373–376. Chauhan, M.S., Pokharia, A.K., Srivastava, R.K., 2015. Late Quaternary vegetation history, climatic variability and human activity in the Central Ganga Plain, deduced by pollen proxy records from Karela Jheel, India. Quat. Int. 371, 144-156. Chauhan, O.S., 2003. Past 20,000 years history of Himalayan aridity: evidence from the oxygen isotope record of Bay of Bengal. Curr. Sci. 87, 90–93. Chauhan, O.S., Vogelsang, E., Basavaiah, N., Kader, U., 2010. Reconstruction of the variability of the southwest monsoon during the past 3 ka, from the continental margin of the southeastern Arabian Sea. Jour. Quat. Sci. 25 (5), 798–807. Collinson, D.W., 1987. Methods in Rock Magnetism and Palaeomagnetism: Techniques and Instrumentation. Chapman & Hall, London. 503 pp. 28

ACCEPTED MANUSCRIPT Dearing, J., 1999. Environmental Magnetic Susceptibility Using the Bartington MS2 System. second edition. Chinese Publications, Kenilworth. Dekkers, M.J., 1997. Environmental magnetism: An introduction. Geol. Mijnbouw 76, 163–182.

T

Demske, D., Tarasov, P.E., Wünnemann, B., Riedel, F., 2009. Late glacial and Holocene

IP

vegetation, Indian monsoon and westerly circulation in the Trans-Himalaya recorded in

Palaeoclimt. Palaeoecol. 279 (3-4), 172-185.

SC R

the lacustrine pollen sequence from Tso Kar, Ladakh, NW India. Palaeogeogr.

Dixit, Y., Tandon, S. K., 2016. Hydroclimatic variability on the Indian subcontinent in the past millennium: Review and assessment. Ear. Sci. Rev. 161, 1–15.

NU

Dunlop, D.J., Ozdemir, Ö., 1997. Rock Magnetism: Fundamentals and Frontiers. Cambridge University Press. 488 pp.

MA

Evans, M.E., Heller, F., 2003. Environmental magnetism: principles and applications of enviromagnetics. Academic press, International Geophysical Series. 293 pp. Fedo, C. M., Nesbitt, H. W., Young, G. M., 1995. Unravelling the effects of potassium in

sedimentary

rocks

and

palaeosols,

with

implications

for

D

metasomatism

TE

palaeoweathering conditions and provenance. Geology 23, 921-924. Fleitmann, D., Burns, S.J., Mangini, A., Mudelsee, M., Kramers, J., Villa, I., Neff, U., Al-

CE P

Subbary, A.A., Buettner, A., Hippler, D., Matter, A., 2007. Holocene ITCZ and Indian monsoon dynamics recorded in stalagmites from Oman and Yemen (Socotra). Quat. Sci. Rev. 26 (1-2), 170-188.

France, D.E., Oldfield, F., 2000. Identifying goethite and hematite from rock magnetic

2795.

AC

measurements of soils and sediments. Jour. Geophys. Res. Solid Earth 105 (B2), 2781–

Galbraith, R.F., Roberts, R.G., Yoshida, H., 2005. Error variation in OSL palaeodose estimates from single aliquots of quartz: a factorial experiment. Radiat. Meas. 39, 289-307. Gasse, F., Arnold, M., Fontes, J.C., Fort, M., Gibert, E., Huc, A., Li, B.Y., Li, Y.F., Lju, Q., Melieres, F., Van Campo, E., Wang, F.B., Zhang, Q.S., 1991. A 13,000-year climate record from Western Tibet. Nature 353, 742-745. Gupta, A.K., Anderson, D.M., Overpeck, J.T., 2003. Abrupt changes in the Asian southwest monsoon during the Holocene and their links to the North Atlantic Ocean. Nature 421, 354–357. Gupta, H. P., Khandewal, A., 1982. Late Holocene palynology from the lake in the sat Tal valley, district Nainital, Kumaun Himalaya, UP: Geophytology. 2 (2), 313-321. 29

ACCEPTED MANUSCRIPT Haug, G.H., Hughen, K.A., Sigman, D.M., Peterson, L.C., Rohl, U., 2001. Southward migration of the intertropical convergence zone through the Holocene. Science. 293, 1304–1308. Hong, Y.T., Hong, B., Lin, Q.H., Zhu, Y.X., Shibata, Y., Hirota, M., Uchida, M., Leng, X.T.,

T

Jiang, H.B., Xu, H., Wang, H., Yi, L., 2003. Correlation between Indian Ocean summer

IP

monsoon and North Atlantic climate during the Holocene. Ear. Plan. Sci. Lett. 211, 371– 380.

SC R

Islam, R., Gururajan, N.S., 1997. Geochemistry and petrogenesis of Lower Palaeozoic meta granites of Lahaul-Spiti region, Himachal Pradesh, India. Geochem. Jour. 31 (1), 1-16. Jacobs, Z., Duller, G.A.T., Wintle, A.G., 2006. Interpretation of single grain De distribution and

NU

calculation of De. Radiat. Meas. 41(3), 264-277.

Jacobs, Z., Wintle, A.G., Roberts, R.G., Duller, G.A.T., 2008. Equivalent dose distributions

MA

from single grains of quartz at Sibudu, South Africa: context, causes and consequences for optical dating of archaeological deposits. Jour. Arch. Sci. 35, 1808-1820. Johnsen, S.J., Dahl-Jensen, D., Gundestrup, N., Steffensen, J.P., Clausen, H.B., Miller, H.,

D

Masson-Delmotte, V., Sveinbjornsdottir, A.E., White, J., 2001. Oxygen isotope and

TE

palaeotemperature records from six Greenland ice-core stations: camp century, Dye-3, GRIP, GISP2, Renland and North GRIP. Jour. Quat. Sci. 16, 299–307.

CE P

Juyal, N., Pant, R.K., Basavaiah, N., Bhushan, R., Jain, M., Saini, N.K., Yadava, M.G., Singhvi, A.K., 2009. Reconstruction of Last Glacial to early Holocene monsoon variability from relict lake sediments of the Higher Central Himalaya, Uttrakhand, India. Jour. Asian Ear. Sci. 34, 437-449.

AC

Kӓӓb, A., Frauenfelder,

.,

oer, ., 200 . On response of rockglacier creep to surface

temperature increase. Global Planet Change.56, 172-87. King, J., and Channell, J.E.T., 1991. Sedimentary magnetism, environmental magnetism, and magnetostratigraphy, in U.S. National Report to the International Union of Geodesy and Geophysics, AGU, Washington, D. C. 29, 358–370. Kotlia, B.S., Shukla, U.K., Bhalla, M.S., Mathur, P.D., Pant, C.C., 1997. Quaternary fluviolacustrine deposits of Lamayuru basin, Ladakh Himalaya: preliminary multidisciplinary investigations. Geol. Mag. 134 (6), 807-812. Kotlia, B.S., Sharma, C., Bhalla, M.S., Rajagopalan, G., Subrahmanyam, K., Bhattacharyya, A., Valdiya, K.S., 2000. Palaeoclimatic conditions in the Late Pleistocene Wadda Lake, eastern Kumaun Himalaya (India). Palaeogeogr. Palaeoclimt. Palaeoecol. 162, 105-118.

30

ACCEPTED MANUSCRIPT Kotlia, B.S., Sanwal, J., Phartiyal, B., Joshi, L.M., Trivedi, A., Sharma, C., 2010. Late Quaternary climatic changes in the eastern Kumaun Himalaya, India, as deduced from multi proxy studies. Quat. Int. 213, 44-55.

T

Kruiver, P.P., Dekkers, M.J., Heslop, D., 2001. Quantification of magnetic coercivity

IP

components by the analysis of acquisition curves of isothermal remanent magnetization. Ear. Plan. Sci. Lett. 189, 269–276.

SC R

Lechler, P. J., Desilets, M. O., 1987. A review of loss on ignition as a measurement of total volatiles in whole rock analysis. Chem. Geol. 63, 341-344.

Leipe, C., Demske, D., Tarasov, P.E., 2013. A Holocene pollen record from the northwestern

NU

Himalayan lake Tso Moriri: implications for palaeoclimatic and archaeological research. Quat. Int. 348, 93-112.

MA

Liu, Q., Roberts, A.P., Torrent, J., Horng, C.S., Larrasoaña, J.C., 2007. What do the HIRM and S-ratio really measure in environmental magnetism? Geochem. Geophys. Geosyst. 8, Q09011. http://dx.doi.org/10.1029/2007GC001717.

D

Liu, Q., Roberts, A.P., Larrasoana, J.C., Banerjee, S.K., Guyodo, Y., Tauxe, L., Oldfield, F.,

TE

2012. Environmental magnetism: principles and applications. Rev. Geophys. 50, RG4002. http://dx.doi.org/10.1029/2012RG000393.

CE P

Lyons, R., Oldfield, F., Williams, E., 2010. Mineral magnetic properties of surface soils and sands across four North African transects and links to climatic gradients. Geochem. Geophys. Geosyst. 11, Q08023. http://dx.doi.org/10.1029/2010GC003183. Maher, B.A., 1988. Magnetic properties of some synthetic sub-micron magnetites. Geophys.

AC

Jour. Int. 94, 83–96.

Maher, B.A., Thompson, R., 1999. Quaternary Climates, Environments and Magnetism. Cambridge University Press. Mayewski, P.A., Rohling, E.E., Stager, C.J., Karlén, W., Maasch, A., Meeker, L.D., Meyerson, E.A., Gasse, F., Van Kreveld, S., Holmgren, K., Lee-Thorp, J., Rosqvist, G., Rack, F., Staubwasser, M., Schneider, R.R., Steig, E.J., 2004. Holocene climate variability. Quat. Res. 62, 243-255. Mazari, R.K., Bagati, T.N., Chauhan, M.S., Rajagopalan, G., 1995. Palaeoclimatic records of last 2000 years in Trans-Himalaya Lahaul-Spiti region. In: Proceedings Nagoya IGBPPages/REP-II Symposium. 262-268. Menzel, P., Gaye, B., Mishra, P.K., Anoop, A., Basavaiah, N., Marwan, N., Plessen, B., Prasad, S., Riedel, N., Stebich, M., Wiesner, M.G., 2014 Linking Holocene drying trends from 31

ACCEPTED MANUSCRIPT Lonar Lake in monsoonal central India to North Atlantic cooling events. Palaeogeogr. Palaeoclimt. Palaeoecol. 410, 164-178. Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using an improved single-

T

aliquot regenerative-dose protocol. Radiat. Meas. 32, 57-73.

IP

Naidu, P.D., 2006. Link between western Arabian Sea surface temperature and summer monsoon strength and high-latitude abrupt climate events. Jour. Geol. Soc. Ind. 68, 379-

SC R

385.

Nesbitt, H. W., Young, G. M., 1982. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites. Nature 299, 715-717.

NU

Nesbitt, H.W., Young, G.M., 1984. Prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations. Geochim.

MA

Cosmochim. Acta 54, 1523–1534.

Nesbitt, H.W., Young, G.M., 1989. Formation and diagenesis of weathering profile. Jour. Geol. 97, 129-147.

D

Oldfield, F., 1991. Environmental magnetism - A personal perspective, Quat. Sci. Rev. 10, 73–

TE

85. doi:10.1016/0277-3791 (91) 90031-O. Owen, L.A., 2009. Latest Pleistocene and Holocene glacier fluctuations in the Himalaya and

CE P

Tibet. Quat. Sci. Rev. 28, 2150-2164. Owen, L. A., Lehmkuhl, F., 2000. Late Quaternary glaciation and palaeoclimate of the Tibetan plateau and bordering mountains. Quat. Int. 65/66, 212. Owen, L.A., Benn, D.I., Derbyshire, E., Evans, D.J.A., Mitchell, W.A., Richardson, S., 1996.

AC

The Quaternary glacial history of the Lahul Himalaya, Northern India. Jour. Quat. Sci. 11 (1), 25-42.

Owen, L.A., Bailey, R.M., Rhodes, E.J., Mitchell, W.A., Coxon, P., 1997. Style and timing of glaciation in the Lahul Himalaya, northern India: A framework for reconstructing the late Quaternary palaeoclimatic change in the Western Himalayas. Jour. Quat. Sci. 12 (2), 83– 109. Pandey, P., Ali, N.S., Ramanathan, A.L., Venkataraman, G., 2016. Regional representation of glaciers in Chandra basin region, western Himalaya, India. Geosci. Front. http://dx.doi.org/10.1016/j.gsf.2016.06.006. Peters, C., Dekkers, M.J., 2003. Selected room temperature magnetic parameters as a function of mineralogy, concentration and grain size. Phys. Chem. Ear. Parts A/B/C 28 (16), 659– 667. 32

ACCEPTED MANUSCRIPT Phadtare, N.R., 2000. Sharp decrease in summer monsoon strength 4000–3500 cal yr BP in the Central Higher Himalaya of India based on pollen evidence from alpine peat. Quat. Res. 53, 122–129.

T

Prasad, S., Anoop, A., Riedel, N., Sarkar, S., Menzel, P., Basavaiah, N., Krishnan, R., Fuller, D.,

IP

Plessen, B., Gaye, B., Rohl, U., Wilkes, H., Sachse, D., Sawant, R., Wiesner, M.G., Stebich, M., 2014. Prolonged monsoon droughts and links of Indo-Pacific warm pool: A

SC R

Holocene record from Lonar Lake, Central India. Ear. Plan. Sci. Lett. 391, 171-182. Pratt-Sitaula, B., Burbank, D.W., Heimsath, A.M., Humphrey, N.F., Oskin, M., Putkonen, J., 2011. Topographic control of asynchronous glacial advances: A case study from

NU

Annapurna, Nepal. Geophys. Res. Lett. 38. doi:10.1029/2011GL049940. Prescott, J.R., Hutton, J.T., 1994. Cosmic ray contributions to dose rates for luminescence and

MA

ESR dating: large depths and long-term time variations. Radiat. Meas. 23, 497-500. Raina, V.K., D. Srivastava. 2008. Glacier atlas of India. Bangalore, Geol. Soc. Ind. 316 pp. Rawat, S., Gupta, A.K., Sangode, S.J., Srivastava, P., Nainwal, H.C., 2015a. Late Pleistocene–

D

Holocene vegetation and Indian summer monsoon record from the Lahaul, North-west

TE

Himalaya, India. Quat. Sci. Rev. 114, 167–181. Rawat, S., Gupta, A.K., Srivastava, P., Sangode, S.J., Nainwal, H.C., 2015b. A 13,000 year

CE P

record of environmental magnetic variations in the lake and peat deposits from the Chandra valley, Lahaul: Implications to Holocene monsoonal variability in the NW Himalaya. Palaeogeogr. Palaeoclimt. Palaeoecol. 440, 116–127. Reineck, H.E., Singh, I.B., 1980. Depositional Sedimentary Environments. Springer Verlag,

AC

Heidelberg. 549 pp.

Roberts, A.P., 1995. Magnetic properties of sedimentary greigite (Fe3S4). Ear. Plan. Sci. Lett. 134 (3), 227–236. Roberts, A.P., Turner, G.M., 1993. Diagenetic formation of ferromagnetic iron sulphide minerals in rapidly deposited marine sediments, South Island, New Zealand. Ear. Plan. Sci. Lett. 115, 257–273. Robertson, D. J., France, D.E., 1994. Discrimination of remanence-carrying minerals in mixtures, using isothermal remanent magnetisation acquisition curves, Phys. Ear. Plan. Inter. 82, 223–234. doi: 10.1016/0031-9201(94)90074-4. Rochette, P., Mathé, P.E., Esteban, L., Rakoto, H., Bouchez, J.L., Liu, Q., Torrent, J., 2005. Non-saturation of the defectmoment of goethite and fine grained hematite up to 57 Tesla. Geophys. Res. Lett. 32, L22309. http://dx.doi.org/10.1029/2005GL024196. 33

ACCEPTED MANUSCRIPT Sangewar, C.V., Shukla, S.P., 2009. Inventory of the Himalayan glaciers (An updated edition). Geol. Sur. Ind. Spec. Pub. 34. Sangode, S. J., Sinha, R,. Phartiyal, B., Chauhan, O. S., Mazari, R. K., Bagati, T. N., Suresh, N.,

T

Mishra, S., Kumar, R., Bhattacharjee, P., 2007. Environmental magnetic studies on some

IP

Quaternary sediments of varied depositional settings in the Indian sub-continent. Quat. Int. 159, 102–118.

SC R

Sarkar, A., Ramesh, R., Somayajulu, B.L.K., Agnihotri, R., Jull, A.J.T., Burr, G.S., 2000. High resolution Holocene monsoon record from the eastern Arabian Sea. Ear. Plan. Sci. Lett. 177, 209–218.

NU

Sati, S.P., Ali, N. S., Rana, N., Bhattacharya, Falguni, Bhushan, Ravi, Shukla, A.D., Sundriyal, Y.P., Navin, J., 2014. Timing and extent of Holocene glaciations in the monsoon

MA

dominated Dunagiri valley (Bangni glacier), central Himalaya, India. Jour. Asian Ear. Sci. 91, 125-136.

Schaefer, J.M., Oberholzer, P., Zhao, Z., Ivy-Ochs, S., Wieler, R., Baur, H., Kubik, P.W.,

D

Schlüchter, C., 2008. Cosmogenic beryllium-10 and neon-21 dating of late Pleistocene

TE

glaciations in Nyalam, Monsoonal Himalayas. Quat. Sci. Rev. 27, 295-311. Sharma, S., Joachimski, M., Sharma, M., Tobschall, H.J., Singh, I.B., Sharma, C., Chauhan,

CE P

M.S., Morgenorth, G., 2004. Late glacial and Holocene environmental changes in Ganga Plain Northern India. Quat. Sci. Rev. 23, 145–159. Shukla, A.D., Bhandari, N., Shukla, P.N., 2002. Chemical signatures of the Permian-Triassic

454. Singh,

D.S.,

AC

transitional environment in Spiti valley, India. Geol. Soc. Amer. Special paper 356, 445-

2013.

Causes

of

Kedarnath

Tragedy

and

Human

Responsibilities.

Jour. Geol. Soc. Ind. 82 (3), 303-304. Singh, D.S., 2014. Surface Processes during flash floods in the glaciated terrain of Kedarnath, Garhwal Himalaya and their role in the modification of landforms, Curr. Sci. 106 (4), 594-597. Singh,

D.

S.,

Singh,

I.B.,

2005.

Facies

architecture

of

the

Gandak

Megafan,

Ganga plain, India. Palaeon. Soc. Ind. Spec. Pub. 2, 125-140. Singh, D.S., Gupta, A.K., Sangode, S.J., Clemens, S.C., Prakasam, M., Srivastava, P., Prajapati, S.K., 2015. Multiproxy record of monsoon variability from the Ganga Plain during 400– 1200 AD. Quat. Int. 371, 157–163.

34

ACCEPTED MANUSCRIPT Singh, D. S., Tangri, A. K., Kumar, D., Dubey, C, A., Bali R., 2016. Pattern of retreat and related morphological zones of Gangotri Glacier, Garhwal Himalaya, India. Quat. Int. http ://dx.doi.org/10.1016/j.quaint.2016.07.025.

T

Singh, J., Yadav, R. R., 2005. Spring precipitation variations over the western Himalaya, India

IP

since AD 1731 as deduced from tree rings, Jour. Geophys. Res., 110, D01110, doi:10.1029/2004JD004855.

SC R

Snowball, I.F., 1991. Magnetic hysteresis properties of greigite (Fe3S4) and a new occurrence in Holocene sediments from Swedish Lappland. Phy. Ear. Plan. Int. 68, 32–40. Soon, W., Velasco Herrera, V.M., Selvaraj, K., Traversi, R., Usoskin, I., Chen, Ch.T.A., Lou,

NU

J.Y., Kao, S., Carter, R.M., Pipin, V., Severi, M., Becagli, S., 2014. A review of Holocene solar-linked climatic variation on centennial to millennial timescales: Physical

MA

processes, interpretative frameworks and a new multiple cross-wavelet transform algorithm. Ear. Sci. Rev. 134, 1-15.

Swaroop. S., Shukla. S. P., Oberoi. L. K., Siddiqui. M. A., Bejarniya. B. R., 2001. Short term

D

runoff and abliation characteristic of Triloknath glacier. Lahul and Spiti district. Geol.

TE

Sur. Ind. Special Pub. 53, 91- 96.

Takahashi, G. 2015. Sample preparation for X-ray fluorescence analysis III. Pressed and loose

CE P

powder methods. Rigaku Jour. 31, 26-30. Thompson, R., Oldfield, F., 1986. Environmental Magnetism. Allen & Unwin London. 227 pp.

Thompson, R., Mortan, D.J., 1979. Magnetic susceptibility and particle size distribution in

AC

recent sediments of Loch Lomond drainage basin, Scotland. Jour. Sed. Pet. 49, 801–812. Thompson, R., Stober, J.C., Turner, G.M., Oldfield, F., Bloemendal, J., Dearing, J.A., Rummery,T.A., 1980. Environmental applications of magnetic measurements. Science 207, 481–486. Tripathi, J. K., Ghazanfari, P., Rajamani, V., Tandon, S. K., 2007. Geochemistry of sediments of the Ganga alluvial plains: Evidence of large-scale sediment recycling in the foreland basin of the Himalaya. Quat. Int. 159, 119-130. Trivedi, A., Chauhan, M.S., 2009. Holocene vegetation and climate fluctuations in North-west Himalaya based on pollen evidence from Surinsar Lake, Jammu region, India. Jour. Geol. Soc. Ind. 74 (3), 402–412.

35

ACCEPTED MANUSCRIPT Trivedi, A., Chauhan, M.S., Sharma, A., Nautiyal, C.M., Tiwari, D.P., 2013. Record of vegetation and climate during Late Pleistocene - Holocene in Central Ganga Plain, based on multiproxy data from Jalesar Lake, Uttar Pradesh, India. Quat. Int. 306, 97-106.

T

Verosub, K., Roberts, A.P., 1995. Environmental magnetism: past, present and future. Jour.

IP

Geophy. Res. 100, 2175–2192.

Von Rad, U., Schulz, H., Riech, V., den Dulk, M., Berner, U., Sirocko, F., 1999. Multiple

SC R

monsoon-controlled breakdown of oxygen-minimum conditions during the past 30,000 years documented in laminated sediments off Pakistan. Palaeogeogr. Palaeoclimatol. Palaeoecol. 152 (1), 129–161.

NU

Watson, J. S. 1996. Fast simple method of powder pellet preparation for X-Ray fluorescence analysis. X-Ray Spectrometry 25, 173-174.

MA

Weiers, S., 1995. Zur Klimatologie des NW-Karakorum und angrenzender Gebiete. Bonner Geogr. Abh. 92, p. 168.

Wulf, H., Bookhagen, B., Scherler, D., 2010. Seasonal precipitation gradients and their impact

D

on fluvial sediment flux in the Northwest Himalaya. Geomorphology 118, 13-21.

TE

Wünnemann, B., Demske, D., Tarasov, P., Kotlia, B.S., Reinhardt, C., Bloemendal, J., Diekmann, B., Hartmann, K., Krois, J., Riedel, F., Arya, N., 2010. Hydrological

CE P

evolution during the last 15 kyr in the Tso Kar lake basin (Ladakh, India), derived from geomorphological, sedimentological and palynological records. Quat. Sci. Rev. 29 (910), 1138-1155.

Yadav, R.R., 2009. Tree ring imprints of long-term changes in climate in western Himalaya.

AC

India. Jour. Bio. Sci. 34, 699–707. Yadav, R.R., 2011. Tree-ring evidence of 20th century precipitation surge in monsoon shadow zone

of

western

Himalaya,

India.

Geophys.

Res.

Lett.

116,

D02112,

http://dx.doi.org/10.1029/2010JD014647. Yang, B., Brauning, A., Dong, Z., Zhang, Z., Keqing, J. 2008. Late Holocene monsoonal temperate glacier fluctuations on the Tibetan Plateau. Glo. Pla. Chan. 60, 126-140. Yao, T., Thompson, L., Yang, W., Yu, W., Gao, Y., Guo, X ., Yang, X., Duan, K., Zhao, H., Xu, B., Pu, J., Lu, A., Xiang, Y., Dambaru B., Kattel, B. D., Joswiak, D ., 2012. Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings. Nature Climate Change 2, 663–667. Zhao, J., Liu, S., He, Y., Song, Y., 2009. Quaternary glacial chronology of the Ateaoyinake River Valley, Tianshan Mountains, China. Geomorphology 103, 276-284. 36

ACCEPTED MANUSCRIPT Zheng, B., 1989. Controversy regarding the existence of a large ice sheet on the Qinghai–Xizang (Tibetan) Plateau during the Quaternary period. Quat. Res. 32, 121–123.

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Caption of Figures

Fig. 1. (A) Location map of the study area. (B) Contour map of the area showing

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distribution of major landforms and location of the pit (after Bali et al., 2016). Fig. 2. (A) Synoptic view of the Triloknath Glacier valley. ( B) Location of Triloknath

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palaeolake between the right lateral moraine and the valley wall. Fig. 3. Litholog of the Triloknath palaeolake deposit (after Bali et al., 2016). The inset

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shows the presence of an organic layer within the pit profile. Fig. 4. Age-depth model for the studied profile at Triloknath palaeolake deposit

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(modified after Bali et al., 2016).

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Fig. 5. Grain size distribution graph against litholog (the climatic zones are based on environmental magnetic parameters).

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Fig. 6. A-CN-K (Al2O3-‘CaO*+Na2O’-K2O; see text for explanation) diagram showing lake sediment samples plotting in a very narrow stretch of the moderately weathered chemical index of alteration (i.e., A component) range. The projection

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from the ‘plagioclase–feldspar join’ suggests evolved upper crustal composition, i.e., between the granite and granodiorite, for the provenance.

Fig. 7. Environmental magnetic parameters plotted against litholog. Fig. 8. Variations of major (in weight %) and trace elements (in ppm) in the Triloknath palaeolake sediments deposit with depth. The CIA (in %) trend with depth has been plotted to understand the weathering trend and the likely climatic situation in the catchment of the lake.

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Highlights

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The paper presents high resolution palaeoclimatic record from Triloknath Palaeolake

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deposit located in north- western part of Lahaul Himalaya. The integration of magnetic and sedimentological and eochemical studies has helped in having a better understanding of climatic fluctuations since mid-Holocene. It is and thus likely to help in building better climatic

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models. OSL and AMS 14C chronology suggests that that lake building activity was initiated at

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~ 6500 cal.yrs. BP and has subsequently been influenced by the climatic conditions, strength of the ISM as well as the intensity of the west disturbances. Based on integration of multiproxy

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data, five climatic zones have been delineated since Mid- Holocene time. The magnetic minerals

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during ~ 5925 cal. yrs. BP to 5676 cal. yrs. BP suggests warm and wet conditions due to enhanced Indian Summer Monsoon (ISM) precipitation corresponding to the Holocene Climate

CE P

Optimum (HCO). Similarly imprints of Medieval Warm Period as well as Little Ice Age (LIA)

AC

as recorded in other parts of the Himalaya have been recorded in the present area of study

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