Neotectonic and climatic impressions in the zone of Trans Himadri Fault (THF), Kumaun Tethys Himalaya, India: A case study from palaeolake deposits

Neotectonic and climatic impressions in the zone of Trans Himadri Fault (THF),

Kumaun Tethys Himalaya, India: A case study from palaeolake deposits

Bahadur S. Kotlia and Lalit M. Joshi

with 4 figures and 1 table

Summary. Late Quaternary tectonic activity on a NW-SE trending fault within the Trans Hi-madri Fault (THF) zone in lower reaches of the Milam glacier (Indian Tethys Himalaya) result-ed in development of a lake around 23 ka BP. The remnants of the ancient lake are preserved inform of a 25.6 m thick lacustrine profile, consisting of muds and sands. The palaeolake seems tohave breached around 11 ka BP possibly due to revival of a further event of neotectonic activi-ty. The geomorphic consequences of the tectonic movements in the fault zone are manifest inform of palaeo-landslide cones, unpaired terraces, fault facets, soaring waterfalls, deep gorgesand slope failures etc. The soft sedimentary structures, e. g., micro-faulting and flame structuresin the exposed profile also point to a possible reactivation of the THF in the Late Pleistocene.We present the first palynological results from otherwise a totally unexplored area in the easternpart of the Indian Tethys Himalaya. The preliminary results indicate that the area experiencedcold desertic climatic conditions from ca. 22.9 to 15.7 ka BP covering a period of Last GlacialMaximum (LGM) and during which the sediment accumulation rate was also extremely slow.This phase was followed by deglaciation together with amelioration of climate between ca. 15.7and 14.5 ka BP. A dry period from ca. 14.5 to 13.8 ka BP can be associated with the Older Dryas.The area underwent wetter/moist conditions from ca. 13.8 to 12.8 ka BP, followed by a centuryscale dry event (ca. 12.8 to 12.7 ka BP) which may be linked to the Younger Dryas episode.

Key words: Trans Himadri Fault, Tethys Himalaya, Neotectonics, Palynological investiga-tions

1 Introduction

The Indian Himalaya has witnessed the intense Quaternary tectonic movements inthe zones of intracrustal boundary faults/thrusts, resulting in damming of rivers andformation of lakes. In the Indian Tethys Himalaya, a number of such tectonicallyformed lakes have been studied from Ladakh (Burgisser et al. 1982, Fort et al. 1989,Kotlia et al. 1997, 1998, Shukla et al. 2002, Upadhyay 2003), Spiti (Mohindra &Bagati 1996, Sangode et al. 2007, Singh & Jain 2007, Phartiyal et al. 2009), Kashmir (Burbank & Johnson 1982) and Kumaun sector (Heim & Gansser 1939,Kotlia & Rawat 2004, Basavaiah et al. 2004, Juyal et al. 2004, 2009, Pant et al.2006, Rawat & Kotlia 2006). Based on the extensive studies, three prominent pulses

Zeitschrift für Geomorphologie Vol. 57,3 (2013), 289–303 Articlepublished online February 2013

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of tectonic activity have been established at ca. 35, 21 and 10 ka BP throughout theIndian Himalaya (Kotlia et al. 2000, 2010) that were responsible for either forma-tion of lakes or closure of some of them (Kotlia et al. 2008). Here, we concentrateon a palaeolake at Burfu village (30° 22� 00.32� N: 80° 11� 01.24� E; altitude 3,275 m) inlower reaches of the Milam glacier (Uttarakhand State, see fig. 1, inset) in the KumaunTethys Himalaya. The lake was formed by the blockade of the Gori River due to reac-tivation of the Trans Himadri Fault (THF) at the confluence of the Gori River andKharkan Kwalta stream. This area is bounded by Main Central Thrust (MCT) in thesouth and THF at the study site (fig. 1a), the later was reactivated in the Late Qua-ternary period (Valdiya 2005) and has been prone to some major earthquakes in thelast about 100 years (see fig. 1b). At least three relict lakes along THF have beennoticed in the eastern Kumaun sector (fig. 1a) and from east to west, these are Gar-byang (Kotlia & Rawat 2004, Basavaiah et al. 2004, Juyal et al. 2004), Burfu (Pantet al. 2006, present work) and Goting (Juyal et al. 2009). In our studied sector, theTHF marks a tectonic boundary between the Great Himalayan Crystalline Complexand Late Proterozoic to Late Cretaceous sedimentary cover of the Tethys domain(Valdiya & Kotlia 2001). The Burfu village and surroundings fall within the rocksof the Martoli Formation (fig. 1a) which rests over the crystalline rocks. It consists ofsteeply dipping biotitic sericite schists, calc-phyllites and quartzitic sandstones, thelater have preserved the sedimentary structures, e. g., graded and cross bedding(Sinha 1989). The arenaceous component is medium to unsorted fine grained sandwith graded and cross bedding structures. The rocks of the Martoli Formation standerect with high angles of dip, indicating irregular deformation patterns. The dip of thehost rocks across the Gori River around Burfu village is steep. The Gori River incisesinto the relict lacustrine deposits exposed on the western bank at Burfu and these arecapped by rock falls and fanglomerates.

2 Examples of neotectonic activity

A number of studies have proved that active tectonics along the boundary thrusts/faults as well as the subsidiary faults/thrusts, provides evidences of recent move-ments. Displaced terraces, alluvial fans, triangular fault facets, high water falls, hugelandslides, entrenched meandering etc. are potential evidences of active tectonics(Nakata 1972, Valdiya 1993, 1999, 2005, Kotlia et al. 2000, 2010). The neotecton-ics is one of the most important agents for triggering the landslides in the Himalayawith immediate risk of flooding the down valleys (Weidinger 1998). Huge landslides(� 1,000 m3) along the THF are frequent and are dominantly controlled by foliationin the metamorphic rocks (Barnard et al. 2004). The THF shows pronounced dipslip movements and the imprints of the neotectonic movements left by these can berecognized in form of the geomorphic rejuvenation of terrain such as deep gorges(fig. 2a), heavy landslide debris (fig. 2b), ancient lake deposits (fig. 2c), formation ofriver terraces (fig. 2d), step-wise vertical and steep waterfalls (fig. 2e) and braided riverchannels (fig. 2f). The braiding Gori River, joined by several fluvial channels down-stream becomes very wide near Rilkot (fig. 2f).

Even today, the tectonically triggered landslides in the Birahi Ganga (east of GoriGanga basin) in western Nepal are responsible for blocking the river course, resultingin the formation of temporary dams (Weidinger 1998). A number of landslides in-

Bahadur S. Kotlia and Lalit M. Joshi290

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Neotectonic and climatic impressions 291

Fig. 1. a. Geological and tectonic map of the study area (After Valdiya 2005). The palaeo-lakes formed along the THF are shown by open circles and Burfu palaeolake is shown by star.b. Digital elevation model of the Gori valley and adjoining areas and seismotectonic maparound study area (earthquake data from 1900 AD onwards from various sources, e. g., IMD,ISC and USGS). Star denotes the Burfu palaeolake.

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Fig. 2. Neotectonic imprints in the THF zone. a. River Gori flowing in deep gorge whilecrossing THF. b. Landslide debris along the course of the river. c. Palaeolake deposits at Burfuvillage. d. Unpaired fluvial terrace along the river. e. Step-wise towering water fall within thefault zone downstream the river between Rilkot and Lilam. f. Braiding of the river downstreamnear Rilkot.

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clude several million cubic meters of debris and are intensely eroded. The channelbars, generally observed during the meandering of the river, consist of cobbles, sandsand silts mainly of glacial origin. In addition, the slope failures are widespread withinthe present-day river bank. The major landslides and rock falls, generally occurringduring the monsoon period, cause partial or complete blockade of the drainage. Allthese geomorphic features suggest strong tectonic movements and nearly all suchstructures are observed around the present study area.

3 Lithology of lake sequence, chronology and soft sediment deformationalstructures

A 25.6 m thick lake profile, showing upward fining sequence, is mainly composed offinely laminated mud, silt and medium-coarse grained sand. The basal most part con-sists of unconsolidated and unsorted gravel with mostly coarse grained sand andangular rock fragments as matrix (fig. 3). In general, the silt horizons show parallel tosub-parallel mm-cm scale laminations. The mud sequence is made up of cm scale lam-inated darker and lighter horizons and gives appearance of the varvites. The sands andsilts in the lower horizons display cross bedding. The upper mud horizons also haveburrow structures. Three OSL dates are available (table 1) to determine the age of theclimatic zones. A rather heterogeneous nature of the deposits and chronologicaluncertainties do not allow us to precisely calculate the mean sedimentation rate.However, the approximate rate of sediment accumulation can be estimated by cali-brating the dates as in Stuiver et al. (1998). By extrapolating dates, we assume anaccumulation rate as 1 m/2,308 yrs between 22 ka BP to 16 ka BP and 1 m/221 yrsbetween 16 ka BP to 11 ka BP. The likely ages of the boundaries of various vegeta-tional zones which are significant in this work, may be assumed ca. 22.9 ka BP (basalmost part), ca. 15.7 ka BP (4.1 m level), ca. 14.5 ka BP (9.9 m level), ca. 13.8 ka BP(12.8 m level), ca. 12.8 ka BP (17.3 m level) and ca. 12.7 ka BP (18.0 m level). Remark-ably slow sediment accumulation in the lowermost part may be due to less erosion inthe lake catchment as a result of less availability of vegetation under the glacial cli-matic conditions.

Presence of soft sediment deformational structures especially in the lowermostsand bed, intercalated with mm-cm scale silty clay horizon indicates the depositionaldisorder soon after the formation of the Burfu lake. Between 35–60 cm level, thedeformed structures occur within undeformed sediment units. Identified as the flamestructures, they are developed in fine sand overlain by silty clay (fig. 3). The flamesof about 3–5 cm length are smooth to sub-angular at the terminal part where they


Table 1. Luminescence (BGSL/OSL) dates from Burfu lake sediments.

Height from Material BGSL/OSL Referencebase (m)

25.6 Carbonaceous mud 11,000 � 100 Pant et al. 20063.0 Silty clay within sand 16,000 � 200 Pant et al. 20060.4 Clay layer within sand 22,000 � 100 Chougaonkar et al. 2004

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appear rising into the underlying sediment layer. They are deformed plastically giv-ing appearance of convolute structures with alternate synclines and anticlines (fig. 3).The deformation is in form of protruding into the underlying silty clay layer. Genet-ically, the flame structures are developed due to the mechanical instability within the sediment layers (Kelling & Walton 1957). From the Burfu profile, Pant et al.(2006) have also reported micro-faulting. Nevertheless, this area has been consideredas seismically very active (Bilham & Gaur 2000, Banerjee & Bürgmann 2002,Paul et al. 2004) and a number of earthquakes of M 5.5 or more have struck the regionsince 1900 (see fig. 1b). We may further mention here that some of the thrusts/faultsin and around Burfu area show evidence of recurrent seismicity (Valdiya 1999,Kotlia et al. 2000, Paul et al. 2004). However, in the present study, it is unclear ifthe structures are a result of seismicity or the tectonics.

4 Methodology and palynological investigations

The Burfu area falls under the alpine zone (3,000–4,500 m) with the hillsides coveredwith bamboo thickets and mixed rain forests and very scanty vegetation. The highalpine forests are composed mainly of silver fir (Abies pindrow), blue pine (Pinusexcelsa), spruce (Picea morinda), Cypress (Cupressus torulosa), deodar (Cedrus deo-dara), birch (Betula utilis), Rhododendron epidotum, Oak (Quercus) and dwarf bamboo (Arundinaria falcate). The birch forests are sustained by Westerlies in thewinters and by Indian Summer Monsoon (ISM) rainfall in summers. The main shrubsbelong to Fabaceae, whereas, the major herbs are Poaceae, Ranunculaceae and Lin-guliflorae. The ISM provides the annual precipitation of 1,550 mm between June andAugust (Indian Meteorological Department 1989) and about 20% of the annual pre-cipitation is contributed by the winter rains (Westerlies) in form of snow. The land-scape is shaped mainly by glaciers.

For pollen study of palaeolake profile, the methodology was taken from Fae-gri & Iverson (1975). A total of 59 out of 80 samples yielded pollen and spores. Allthe pollen samples, as a whole, were poor in pollen content and the uppermost sam-ples were found barren. 50 gm of each sample was boiled in 10% KOH solution for5–10 minutes and stirred to remove any lumps, followed by filtering through a sieve(100 mesh) to remove particles bigger than the pollen grains and the deflocculatedsample (filtrate) was then centrifuged to obtain clear liquid. Thereafter, the liquid wasdecanted and kept in 35–40% hydrofluoric acid for 7–8 days and later washed andkept in centrifuge. This residue was washed with glacial acetic acid and again cen-trifuged. This was followed by acetolysis and heating. The samples then were re-washed and filtered through 500 micron sieve. Finally, the material was stored in vialtubes containing 50% glycerine and a few drops of phenol were added. The pollendiagram was constructed based on the pollen sum of the total terrestrial pollen count.Based on the occurrence of pollen, five zones (Zone-I to Zone-V) in ascending ordercan be described as below.

Zone-I (0–4.1 m). Except Abies, most trees (e. g., Juglans, Betula, Ulmus, Picea,Carpinus, Alnus) are very poorly represented in this zone. Among shrubs, Fabaceae(1–10%) has sporadic occurrence. Artemisia is absent and marshy elements such asPoaceae (up to 20%) also do not show significant development. Cyperaceae has


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insignificant appearance. Both monolete and trilete ferns (less than 10%) are also veryfeebly represented. However, this zone is dominated by Chenopodiaceae (up to45%) and fungal spores.

Zone-II (4.1 m–9.9 m). An abrupt rise in both arboreal and non-arboreal pollen characterizes this zone. A number of trees (e. g., Abies, Pinus, Quercus, Betula, Jug -lans, Ulmus etc.), shrubs (e. g., Fabaceae), marshes (Poaceae), considerable number ofherbs as well as ferns may have formed a luxuriant vegetation during this period.Interestingly, Poaceae (up to 40–45%) registers the maximum values and perennialherbs (Moriceae, Urticaceae) shows rising tendency. Artemisia appears in this zone,whereas, Chenopodiaceae is nearly absent. Fabaceae (up to 30%) and both types offerns show increasing trend. The fungal spores exhibit declining tendency, comparedto that in the preceding zone.

Zone-III (9.9 m–12.8 m). A gradual decline in the arboreals is noticed in this zone.Abies and Pinus show sweeping declining trend, whereas, Quercus has sluggishdecrease and a gradual decline is exhibited by Betula, Juglans and Ulmus. In generalthis zone seems to represent only a few trees elements. Among non-arboreals,Poaceae is significantly declined and Fabaceae is disappeared. Other herbs, such asTubuliflorae and Moriceae are present in insignificant amount. Similarly, the fernspores are also reduced. However, Chenopodiaceae (up to 25%) re-appears in thiszone which is also characterized by the first appearance of Ranunculaceae althoughwith very low frequency.

Zone-IV (12.8 m–17.3 m). This is another distinct zone showing expansion and goodquality growth of trees as well as herbs. Among trees, rapid rise in Abies, Quercus,Juglans, Pinus, Ulmus, Betula and Carpinus makes this zone almost occupied by arboreal pollen. Similarly, Poaceae and Ranunculaceae and Artemisia also show im-proved frequencies. The monolete and trilete ferns are persistent and Chenopodiaceaeis nearly missing. The fungal spores are common, although with variable values.

Zone-V (17.3 m–18.0 m). This zone is characterized by constant decline of tree ele-ments including the disappearance of Abies, Juglans and Alnus. Quercus, Betula,Carpinus and Ulmus exhibit diminishing trend. Similar declining tendency is ob -served in Poaceae and Artemisia. Among other herbs, Ranunculaceae, Urticaceae andTubuliflorae are vanished. Moreover, the fungal spores are also decreased. The fernsare more or less disappeared.

5 Discussion

Based on the available chronology, the pollen spectrum seems to span between ca.22.9 and 12.7 ka BP. Although the chronology of the lake profile is weak and the paly-noflora are fewer to reconstruct the palaeoclimate, yet this study becomes significantto understand the past vegetation in such an unexplored part of the Indian TethysHimalaya.

In the zone-I (ca. 22.9–15.7 ka BP), extremely low frequencies of most trees,near absence of the steppe vegetation (e. g., Artemisia), low values of marshy elements


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(e. g., Poaceae), poor representation of shrubs (e. g., Fabaceae) and extremely highervalues of Chenopodiaceae clearly indicate a desertic climate perhaps under cold con-ditions. This may represent the widespread unfavourable conditions during the LastGlacial Maximum (LGM). Extremely slow rate of sediment accumulation rate dur-ing this period may be a result of the desertic conditions during the LGM.

The global LGM, spanning from ca. 24–18 ka BP is considered as the mostrecent prolonged cold phase in the Earth’s history, yet the terrestrial proxy evidencessuggest significant regional variation in the degree of climate change during thisperiod (Allen et al. 2007). In the most High Himalayan and Tibetan regions, glaciersreached to their maximum extent early in the Last Glacial cycle (Owen 2009). WithinAsia itself, the advance of glaciers from one region to other are asynchronous (Gille-spie & Molnar 1995, Benn & Owen 1998), some of them reached their maximumextent early in the last glacial cycle, around 25 ka BP (Owen et al. 2008). Since thefluctuations in the Himalayan glaciers are controlled by variations in both IndianSummer Monsoon (ISM) and the mid-latitude Westerlies (Owen et al. 2008), it isobvious that the duration of LGM in Tethys Himalaya may differ from that in thelow-lying humid valleys. The so called less humid conditions from ca. 18.2 ka BPonwards in the humid Central Himalaya (Kotlia et al. 2000) may be linked with thepart of the LGM. The cold and drier episode of LGM, spanning between ca. 20.0–18.0 is also reported from the low altitudes (ca. 1,600 m) in the eastern IndianHimalaya (Kotlia et al. 2010). A relatively weak ISM intensity representing the gla-cial and arid conditions (Van Campo 1986, Sarkar et al. 1990) has been recordedfrom Arabian Sea between 20.0 and 19.3 ka BP (Sirocko et al. 1996). Therefore, weassume that the effect of the LGM was longer in the Tethys Himalaya compared tothat in the Lesser Himalaya and Indian Peninsula.

The Zone-II (ca 15.7 to 14.5 ka BP) is characterized by suddenly elevated dis-tribution of the arboreal as well as non-arboreal taxa. The expansion of trees (e. g.,Pinus, Betula, Ulmus, Abies, Carpinus, Quercus), abundant growth of herbaceousplants, highest frequency of marshy vegetation (e. g., Poaceae), shrubs (e. g., Faba -ceae) and herbs (e. g., Tubuliflorae), and increasing trend in Urticaceae, appearance ofsteppe vegetation, abrupt rise in fern spores and disappearance of Chenopodiaceaeclearly point to the onset of climatic amelioration. This scenario also indicatestowards soil moisture and shady habitat in the vicinity of lake. This duration can beascribed to the post-LGM warming responsible for luxuriant growth of vegetationand availability of the soil. A large part of the sediments were perhaps supplied to thelake during this humid phase as is evident by the larger sediment accumulation rate.The post-LGM warming in the Spiti-Lahaul (Baralacha Pass) Himalaya is confirmedby organic enrichment in the lake, reduced mineral phase, intense chemical weather-ing, raised precipitation and high lake level (Bohra 2010). In Kashmir, the deglacia-tion began at ca. 15.0 ka BP (Singh & Agrawal 1976), whereas, Ladakh witnessedpost-LGM warmth at around 15.8 ka BP (Bhattacharyya 1989). In the low lyingCentral Himalaya, a period around ca. 18.5–14.3 ka BP has been recognized as warm/wet/moist during which the precipitation was greatly improved especially at ca.15.2 ka BP (Kotlia et al. 2010).

The high proportion of Chenopodiaceae in the Zone-III (ca 14.5 to 13.8 ka BP)points to the desertic conditions. The appearance of Ranunculaceae may indicate coldclimatic conditions as most of the members of this family are found in the colder


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regions of the world. The diminution of Artemisia further proves that the area didnot support the steppe flora during this period. Above all, the decrease in marshy ele-ments and herbaceous plants together with fern spores proves that this age bracketaround Milam and surroundings experienced cold and desertic conditions. Spanningfor a few centuries, this episode may be interpreted as the Older Dryas (OD) whichis commonly documented as the dry/cold phase. This event has also been docu-mented in the eastern Central Himalaya at ca. 14.3–13.8 ka BP (Kotlia et al. 2010).

A return to the amelioration of the climate may have taken place in the area fromca. 13.8 to 12.8 ka BP (Zone-IV) during which the trees, shrubs, herbs and ferns wereregenerated. On one hand, the desertic taxa (e. g., Chenopodiaceae) became insignif-icant and on other hand, the steppe vegetation (e. g., Artemisia) grew generously. Anumber of arboreals such as Abies, Quercus, Juglans, Betula, Ulmus etc. were im -proved and the marshy elements (e. g., Poaceae) were also rapidly increased.

Pollen zone-V (ca. 12.8 to 12.7 ka BP), representing a century scale dry event ischaracterized by a sharp decline in most trees and Poaceae as well as the absence ofherbs. This short spike seems to be connected with the Younger Dryas (YD) whichis known globally as a cold and dry event. In the Himachal Tethys Himalaya, thepollen records from Chandra peat deposits have captured signatures of this event atca. 12.8 ka BP, coinciding with termination of the Allerød interstadial and beginningof the cold climate (Rawat et al. 2012). In the Trans Himalaya, an age bracket of ca. 12.5–11.3 ka BP is characterized by low Kaolinite, LOI, SiO2, high Muscovite, K,Ti, Fe, MgO, TiO2, Na2O, and positive δ13C values in a varve sequence-all indicatinglow weathering and cold/arid conditions during the YD (Bohra 2010). This event isalso consistent in the low lying humid valleys of the Indian Himalaya, for example,in eastern part, prevalence of cold/dry conditions between ca. 13.0–12.5 ka BP cor-respond to the increased δ18O values in a stalagmite (Sinha et al. 2005), suggestingweak precipitation. A cold/dry episode around 12.5 ka BP has been assigned as YDin the western continental margin of India (Chauhan et al. 2000) and is also consis-tent in the Ganga Plains (Sharma et al. 2004) with the age uncertainties.

6 Conclusions

A number of lakes were either formed or disappeared at ca. 21 ka BP due to a promi-nent tectonic activity throughout the Lesser Himalaya (Kotlia et al. 2008, 2010). Itseems that this event was also felt in the Kumaun Tethys Himalaya when the Burfulake was formed due to damming of the Gori river as a result of the tectonic move-ments in the zone of the THF. The lake may have breached around 11 ka BP due toa further event of tectonics leaving behind a 25.6 m thick upward fining lake sequence,composed of sand, silt and alternating mud. Extremely reduced sedimentation rate inthe lower part of the palaeolake profile may have been a result of the glacial environ-ment. There are examples that some of the Himalayan lakes were partially closedaround this time (see Kotlia et al. 2000). The triangular fault facets, large scale massmovements, landslides incorporating huge debris, gorges and unpaired fluvial ter-races around the area are the imprints, left by the tectonic activity and landscape reju-venation. Supporting Valdiya (2005), we suggest that the area, especially the THFzone has undergone the recent tectonic movements. Micro-faulting and loading (asreported by Pant et al. 2006) and flame structures in the lake sequence may also be


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attributed to either neotectonic activity or to drag exerted by the fast-flowing mass.The preliminary palynological results show that the most of the pollen grainsrecorded in the study site are from the surrounding areas as most of the pollen sporesin the lake profile belong to the local flora.

Based on the palaeo-vegetational investigations, we suggest that during LGM,the Burfu and surrounding areas were generally devoid of vegetation and received lessmoisture under the desertic regime. The deglaciation initiated around 15.7 ka BPwhich is roughly similar to that in Kashmir (e. g., Singh & Agrawal 1976) and some-what later than in the Himalayan valleys (e. g., Kotlia et al. 2000). Following Benn &Owen (1998), we suggest that around LGM, the glacial advances were indeed notsynchronous throughout the Himalaya. A cold spike of the Older Dryas event isfound from ca. 14.5 to 13.8 ka BP. The luxuriant growth of vegetation under wetterand warmer setting prevailed from ca. 13.8 to 12.8 ka BP. The area further accom-plished cold and desertic climate between ca. 12.8 to 12.7 ka BP during which mostarboreals and non-arboreals were nearly vanished. These climatic oscillations mayhave helped in driving the major landscape changes in the Gori river basin.

Acknowledgements

We are thankful to Dr. Chayya Sharma, Birbal Sahni Institute of Palaeobotany, Lucknow forhelping in precise identification of pollen spores. Thanks are due to the Centre of AdvancedStudy in Geology and Uttarakhand Centre on Climate Change, Kumaun University for pro-viding necessary facilities. We also express gratitude to the University Grants Commission,New Delhi for financial support.

References

Allen, R., Siegert, M. J. & Payne, A. J. (2007): Reconstructing glacier-based climates of LGMEurope and Russia – Part 2: A dataset of LGM climates derived from degree-day mod-eling of palaeo glaciers. – Climate Past Discussions 3: 1167–1198.

Banerjee, P. & Bürgmann, R. (2002): Convergence across the Northwest Himalaya fromGPS measurements. – Geophysical Research Letters 29(13): 30–34.

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, GoriGanga, Nanda Devi, NE Garhwal. – Geomorphology 61: 91–110.

Basavaiah, N., Juyal, N., Pant, R. K., Yadava, M. G., Singhvi, A. K. & Appel, E. (2004):Late quaternary climate changes reconstructed from mineral magnetic studies fromproglacial lake deposits of Higher Central Himalaya. – Journal of Indian GeophysicalUnion 8(1): 27–37.

Benn, D. I. & Owen, L. A. (1998): The role of the Indian summer monsoon and the mid-lati-tude westerlies in Himalayan glaciation: review and speculative discussion. – Journal ofthe Geological Society of London 155: 353–363.

Bhattacharyya, A. (1989): Vegetation and climate during the last 30,000 years in Ladakh. –Palaeogeography Palaeoclimatology Palaeoecology 73: 25–38.

Bilham, R. & Gaur, V. K. (2000): Geodetic contribution of the study of seismotectonics inIndia. – Current Science 79(9): 1259–1269.


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Bohra, A. (2010): Palaeoclimatic Changes Using Varve Deposits around Baralachala Pass,Great Himalayan Range, Northwest Himalaya. – Unpublished Ph. D. Thesis, KumaunUniversity, Nainital, 156 p.

Burbank, D. W. & Johnson, G. D. (1982): Intermontane-basin development in the past 4 Myrin the north-west Himalaya. – Nature 298: 432–436.

Burgisser, H. M., Gansser, A. & Pika, J. (1982): Late glacial lake sediments of the Indus val-ley area, northwestern Himalaya. – Eclogae Geologae Helveticae 75: 51–63.

Chauhan, O. S., Sukhija, B. S., Gujar, A. R., Nagabhushanam, P. & Paropkari, A. L.(2000): Late-Quaternary variations in clay minerals along the SW continental margin ofIndia: evidence of climatic variations. – Geo-Marine Letters 20(2): 118–122.

Chougaonkar, M. P., Basavaiah, N. & Kotlia, B. S. (2004): Geological dating of a Hima -layan palaeolake sequence using blue light stimulated luminescence. – Proceedings ofInternational conference on Luminescence and its Applications, 189–192.

Faegri, K. & Iversen, J. (1975): Textbook of Pollen Analysis. – 3rd edition, Scandinavian Uni-versity Books, Copenhagen, 294 p.

Fort, M., Burbank, D. W. & Freytet, P. (1989): Lacustrine sedimentation in a semiaridAlpine setting: An example from Ladakh, northwestern Himalaya. – Quaternary Re -search 31: 332–350.

Gillespie, A. & Molnar, P. (1995): Asynchronous maximum advances of mountain and con-tinental glaciers. – Reviews of Geophysics 33: 311–364.

Heim, A. & Gansser, A. (1939): Central Himalaya, Geological Observations of the SwissExpedition in 1936. – Memoires de la Societe Helvetique Sciences Naturelles 73: 1–245.

Indian Meteorological Department (1989): Climate of Uttar Pradesh. – Government ofIndia Publication, New Delhi, 372–375 pp.

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 vari-ability from relict lake sediments of the Higher Central Himalaya, Uttarakhand, India. –Journal of Asian Earth Sciences 34: 437–449.

Juyal, N., Pant, R. K., Basavaiah, N., Yadava, M. G., Saini, N. K. & Singhvi, A. K. (2004):Climate and seismicity in the higher Central Himalaya during 20–10 ka: evidence fromthe Garbayang basin, Uttaranchal, India. – Palaeogeography, Palaeoclimatology, Palaeo -ecology 213: 315–330.

Kelling, G. & Walton, E. K. (1957): Load cast structures, their relationship to upper surfacestructures and their mode of formation. – Geological Magazine 94: 481–490.

Kotlia, B. S., Hinz-Schallreuter, I., Schallreuter, R. & Schwarz, J. (1998). Evolutionof Lamayuru palaeolake in the Trans Himalaya: Palaeoecological implications. – Eis -zeitalter und Gegenwart, 48: 23–36.

Kotlia, B. S. & Rawat, K. S. (2004): Soft sediment deformation structures in the Garbyangpalaeolake: Evidence from the past shaking events in the Kumaun Tethys Himalaya. –Current Science 87(3): 377–379.

Kotlia, B. S., Sanwal, J. & Bhattacharya, S. K. (2008): Climatic record between ca. 31 and22 ka BP in east-central Uttarakhand Himalaya, India. – Himalayan Geology 29(1): 25–33.

Kotlia, B. S., Sanwal, J., Phartiyal, B., Joshi, L. M., Trivedi, A. & Sharma, C. (2010): LateQuaternary climatic changes in the eastern Kumaun Himalaya, India, as deduced frommulti-proxy studies. – Quaternary International 213: 44–55.

Kotlia, B. S., Sharma, C., Bhalla, M. S., Rajagopalan, G., Subrahmanyam, K., Bhat-tacharyya, A. & Valdiya, K. S. (2000): Paleoclimatic conditions in the late PleistoceneWadda lake, eastern Kumaun Himalaya (India). – Palaeogeography, Palaeoclimatology,Palaeoecology 162: 105–118.


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Kotlia, B. S., Shukla, U. K., Bhalla, M. S., Mathur, P. D. & Pant, C. C. (1997): Quaternaryfluvio-lacustrine deposits of the Lamayuru basin, Ladakh Himalaya, preliminary multi-disciplinary investigations. – Geological Magazine 134(6): 807–812.

Mohindra, R. & Bagati, T. N. (1996): Seismically induced soft sediment deformation struc-tures (seismites) around Sumdo in the Lower Spiti valley (Tethys Himalaya). – Sedimen-tary Geology 101: 69–83.

Nakata, T. (1972): Geomorphic history and crustal movements of the foothills of theHimalayas. – Scientific Report of Tohoku University Japan, 7th series (Geography) 22:39–177.

Owen, L. A. (2009): Latest Pleistocene and Holocene glacier fluctuations in the Himalaya andTibet. – Quaternary Science Reviews 28: 2150–2164.

Owen, L. A., Caffee, M. W., Finkel, R. C. & Seong, Y. B. (2008): Quaternary glaciation of theHimalayan–Tibetan orogen. – Journal of Quaternary Science 23(6–7): 513–531.

Pant, R. K., Juyal, N., Basavaiah, N. & Singhvi, A. K. (2006): Later Quaternary glaciationand seismicity in the Higher Central Himalaya: Evidence from Shalang basin (Gori-ganga), Uttaranchal. – Current Science 90(11): 1500–1505.

Paul, A., Wason, H. R., Sharma, M. L., Pant, C. C., Norwan, A. & Tripathi, H. B. (2004):Seismotectonic implications of data recorded by DTSN in the Kumaun region ofHimalaya. – Journal of Geological Society of India 64: 43–51.

Phartiyal, B., Sharma, A., Srivastava, P. & Ray, Y. (2009): Chronology of relict lakedeposits in the Spiti river, NW Trans Himalaya: Implications to late Pleistocene-Holo -cene climate-tectonic perturbations. – Geomorphology 108: 264–272.

Rawat, K. S. & Kotlia, B. S. (2006). Some examples of flame structures from the Garbyangpalaeolake, Kumaun Tethys Himalaya. – Journal of Geological Society of India 68: 639–647.

Rawat, S., Phadtare, N. R. & Sangode, S. J. (2012): The Younger Dryas cold event in NWHimalaya based on pollen record from the Chandra Tal area in Himachal Pradesh,India. – Current Science 102(8): 1193–1198.

Sangode, S. J., Sinha, R., Phartiyal, B., Chauhan, O. S., Mazari, R. K., Bagati, T. N.,Suresh, N., Mishra, S., Kumar, R. & Bhattacharjee, P. (2007): Environmental mag-netic studies on some Quaternary sediments of varied depositional settings in the Indiansub-continent. – Quaternary International 159: 102–118.

Sarkar, C., Ramesh, R., Bhattacharya, S. K. & Rajagopalan, G. (1990): Oxygen isotopeevidence for a stronger winter monsoon current during the last glaciation. – Nature 343:549–551.

Sharma, S., Joachimski, M., Sharma, M., Tobschall, H. J., Singh, I. B., Sharma, C.,Chauhan, M. S. & Morgenroth, G. (2004): Late glacial and Holocene environmentalchanges in Ganga plain, northern India. – Quaternary Science Reviews 23: 145–159.

Shukla, U. K., Kotlia, B. S. & Mathur, P. D. (2002): Sedimentation pattern in a trans-Himalayan Quaternary lake at Lamayuru (Ladakh), India. – Sedimentary Geology 148:405–424.

Singh, G. & Agarwal, D. P. (1976): Radiocarbon evidence for deglaciation in northwesternHimalaya, India. – Nature 260: 233.

Singh, S. & Jain, A. K. (2007): Liquefaction and fluidization of lacustrine deposits fromLahaul-Spiti and Ladakh Himalaya: Geological evidences of palaeoseismicity alongactive fault zone. – Sedimentary Geology 196: 47–57.

Sinha, A., Cannariato, K. G., Stott, L. D., Li, H. C., You, C. F., Cheng, H., Edwards,R. L. & Singh, I. B. (2005): Variability of southwest Indian summer monsoon precipita-tion during the Bølling–Ållerød. – Geology 33(10): 813–816.

Sinha, A. K. (1989): Geology of the Higher Central Himalaya. – John Wiley and Sons, Chi-chester, 219 p.


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Sirocko, F., Grabe-Schonberg, D., McIntyre, A. & Molfino, B. (1996): Teleconnection1996 between subtropical monsoon and high-latitude climates during the last glacia-tion. – Science 272: 526–529.

Stuiver, M., Reimer, P. J., Bard, E., Beck, J. W., Burr, G. S., Hughen, K. A., Kromer, B.,Mccormac, F. G., Plicht, J. & Spurk, M. (1998): Radiocarbon calibration programmereview. – Radiocarbon 40(1/2): 1041–1083.

Upadhyay, R. (2003): Earthquake-induced soft-sediment deformation in the lower Shyokriver valley, northern Ladakh, India. – Journal of Asian Earth Sciences 21: 413–421.

Valdiya, K. S. (1993): Uplift and geomorphic rejuvenation of the Himalaya in the Quaternaryperiod. – Current Science 64(11/12): 875–885.

Valdiya, K. S. (1999): Reactivation of faults, active folds and geomorphic rejuvenation in east-ern Kumaun Himalaya: wider implications. – Indian Journal of Geology 1–2: 53–63.

Valdiya, K. S. (2005): Trans Himadri Fault: tectonics of a detachment system in Central sec-tor of Himalaya, India. – Journal of Geological Society of India 65: 537–552.

Valdiya, K. S. & Kotlia, B. S. (2001): Fluvial geomorphic evidence for Late Quaternary reac-tivation of a synclinally folded nappe in Kumaun Lesser Himalaya. – Journal of Geolog-ical Society of India 58: 303–317.

Van Campo, E. (1986): Monsoon fluctuations in two 20,000 yr BP oxygen isotope pollenrecord of south-west, India. – Quaternary Research 26: 376–388.

Weidinger, J. T. (1998): Case history and hazard analysis of two lake-damming landslides inthe Himalayas. – Journal of Asian Earth Sciences 16: 323–331.

Manuscript received: August 2012; accepted: November 2012.

Address of the authors: Centre of Advanced Study in Geology, Kumaun University, TheDurham, Nainital, India, 263002; Corresponding author: [email protected]


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Neotectonic and climatic impressions in the zone of Trans Himadri Fault (THF), Kumaun Tethys Himalaya, India: A case study from palaeolake deposits

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