Impact of Climate on the Evolution of Vegetation in Tectonically Active Karewa Basin, Kashmir Himalayas

J. Earth Syst. Sci. (2021) 130:93 Ó Indian Academy of Sciences

https://doi.org/10.1007/s12040-021-01586-2 (0123456789().,-volV)(0123456789().,-volV)

Impact of climate on the evolution of vegetation in tectonically active Karewa basin, Kashmir Himalayas

1, 1 1 1 ANJUM FAROOQUI *, SURESH KPILLAI ,DEEPA AGNIHOTRI ,SALMAN KHAN , 1 1 1 1 RAJNI TEWARI ,SUNIL KSHUKLA ,SAJID ALI ,ANJALI TRIVEDI , 2 1 3 1 SKPANDITA ,KAMLESH KUMAR ,GDBHAT and RAJESH AGNIHOTRI 1Birbal Sahni Institute of Palaeosciences, 53, University Road, Lucknow 226 007, India. 2Department of Geology, University of Jammu, Jammu 180 006, India. 3Directorate of Geology and Mining, Jammu and Kashmir Government, Srinagar, India. *Corresponding author. e-mail: afarooqui˙[email protected]

MS received 8 September 2020; revised 19 January 2021; accepted 22 January 2021

The rise of the Himalayas governed the Indian Summer Monsoon in Karewa basin during Plio-Pleistocene. A palynological study is presented to delineate the climate-vegetation relationship using an 8.5-m thick Cuvio-lacustrine sequence of the Hirpur Formation (2.4–2.1 Ma). Our results suggest that the sediment sequence is mainly comprised of two units, namely, Unit 1 and Unit 2. Unit 1 shows the dominance of sub-tropical to broad-leaf temperate vegetation when mean annual temperature (MAT) was *17°C and mean annual precipitation (MAP) was 1025 mm. The subsequent increase in sand followed by a thin lignite layer with Trapa megafossil (fruits) demarcates Cuvial adjustments, suggesting a low altitude Cuvio-lacustrine ecosystem. Conversely, Unit 2 shows a decline in rainforest pollen with a steady increase in conifers. The abrupt dominance of diatom species Tetracyclus lacustris and related species with MAT and MAP reducing to 10°C and 770 mm reveal a colder climate with the lacustrine ecosystem. This change of tropical to cool temperate vegetation could be attributed to the altitudinal rise of the Pir Panjal Mountains and consequent obstruction of the south-west monsoon, which resulted in lower precipitation and temperature during *2.4–2.1 Ma. Hence, the relic tropical Cora of Palaeogene/Neogene transformed to Himalayan temperate Cora sometime *2.1 Ma. Keywords. Palynology; diatoms; sponge spicules; sediment texture; Karewa; Indian summer monsoon.

1. Introduction (Kashmir valley, India), Kathmandu basin (Cen- tral Nepal) and Heqing basin (Yunnan, China) in A series of upliftment in Himalayas following the the Himalayan region (Fujii and Sakai 2002; collision of Indian and Tibetan plates during late Goddu et al. 2007). The organic matter buried in Cenozoic time period had a profound impact on these lacustrine sediments indicates climatic vari- global climate and also in the region through ability and landscape changes primarily inCuenced mechanical, thermal and weathering eAects (Prell by Quaternary glacial and interglacial cycles (Fujii and Kutzbach 1992; Raymo and Ruddiman 1992). and Sakai 2002; Mampuku et al. 2004). The chan- The few sedimentary archives that provide the ges in Plio-Pleistocene climate, tectonics in Pir records of climate–vegetation relationship of Plio- Panjal Range of Himalaya played a key role in the Pleistocene time period are the Karewa Group geomorphic evolution of Karewa Lake in Kashmir 93 Page 2 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 1. (a–d) The evolution of Karewa basin since 4 Ma to present and the location of the study site (modiBed after Dar et al. 2014b).

Table 1. Lithology of 8.5 m river-cut section of Lower Karewa beds along Ningle Nala, Butapathri, Kashmir. Sample no. Depth Group Formation (Buta-Pathri) (cm) Colour Lithology Chronology Recent Sand Clay Gravel Holocene Karewa Nagum Formation Gravel, sand marl, sandy clay, silt, Early clay Pleistocene Hirpur Formation 12 (TOP) 541–626 Light grey Clay with parallel lamination (Lower Karewas) containing pinch and swell structures 11 494–541 Light brown Sand 10 456–494 Light greenish Corser sand with parallel yellow lamination containing pinch and swell structures 9 446–456 Black Coal (lignite) 8 422–446 Grey/light Very Bne clay/mudstone with yellow parallel lamination 7 397–422 Light grey Clay 6 355–372 Light yellow Parallel laminated clay 5 315–323 Black Coal (lignite) 4 255–315 Black Lignite band with sand 394–147 Green Clay with parallel lamination 260–80 Grey Carbonaceous shale with lignite band 1 (Bottom) 0–50 Greenish light Silty clay grey ...... Unconformity...... Panjal Volcanics (permo-Carboniferous/Triassic Limestone) J. Earth Syst. Sci. (2021) 130:93 Page 3 of 21 93 valley (Burbank 1983; Agrawal et al. 1989; Dar Dodia et al. 1984; Gupta et al. 1985; Sharma et al. et al. 2014a, b). Studies reveal that the sedimen- 1985; Sharma and Gupta 1985; Gupta and Khan- tary sequence of the Hirpur Formation (Lower delwal 1986; Dodia 1988). The faunal records also Karewa) is known to represent the Brst interglacial support the low altitude warmer climate (Sahni period of the Quaternary period (DeTerra and and Kotlia 1983, 1985; Kotlia 1985). Paterson 1939; Wadia 1976). The most compre- The rainforest Cora that occupied the entire hensive chronology of sedimentary deposits from Indian sub-continent during the Palaeogene/Neo- the Kashmir basin has been earlier discussed in gene is now conBned to South-Western Ghats and detail by Singh (1982), Burbank (1982) and Bur- north-eastern part of India because of relatively bank and Johnson (1983). Recently, a palaeomag- high rainfall only in these regions (Prasad et al. netic data between 4.4 and 0.77 Ma was recorded 2009; Farooqui et al. 2010). An overall tendency of from Romushi river cut section (Basavaiah et al. increasing dry climate and downfall of the rain- 2010). These Bndings suggest Indian Summer forest from Tertiary to the late Pleistocene has Monsoon (ISM) weakened over the Kashmir valley been observed and these go well with Bndings in after *1.95 Ma. The remains of Cora from Hirpur Siwalik sediments of northwest India, Karewa Formation (Lower Karewa Lake sediments) are deposits of Kashmir valley and lacustrine deposits scant but indicate low altitude, tropical rainforests of Tibetan Plateau (Basavaiah et al. 2010; Singhvi pollen and diatoms (Gandhi and Mohan 1983; et al. 2011). The ISM variability during the Qua- ternary period has been studied earlier (An et al. 2011; Saraswat et al. 2014 and references therein). However, the details of the vegetation in equilib- rium with the Quaternary climatic spasms are

Figure 2. Lithology details of the Ningle Nala section, Figure 3. A comparative account of chronology and lithology Butapathri, Kashmir. of the Ningle Nala section, Butapathri. 93 Page 4 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 4. Palynological spectrum and climatic phases of Ningle Nala section, Butapathri, Kashmir.

Figure 5. Relative percentages of freshwater diatoms and sediment texture of Ningle Nala section, Butapathri, Kashmir.

scant (Krishnamurthy et al. 1986; Agrawal et al. subsequent shift in Indian Summer Monsoon in 1989; Farooqui et al. 2014) from the Indian the Himalayan region during early–middle sub-continent. Scant palynological records (Nair Pleistocene. 1960; Mohan and Vora 1987) are only available from the exposed sedimentary sections of Lower Karewa. Therefore, here we provide an extensive 1.1 Stratigraphic background of the study area record of more than 80 taxa of subtropical to temperate rainforest diversity, diverse diatom and The Kashmir valley is an intermontane basin in the freshwater sponge species and sediment Western Himalayas of Indian sub-continent. On depositional environment responding to the rise of the west, it is Canked by Tethyan belt and the Pir Pir Panjal mountain ranges and the time period of Panjal mountain ranges, and on the eastern side by J. Earth Syst. Sci. (2021) 130:93 Page 5 of 21 93

Figure 6. Relative percentages of freshwater sponges (microscleres and gammoscleres) of Ningle Nala section, Butapathri, Kashmir.

Figure 7. Cumulative record of different proxies and climatic/ecological interpretations of Ningle Nala section, Butapathri, Kashmir. the Greater Himalayas (Bgure 1a). Around 4 Ma intercalated lignite beds and unconsolidated con- ago, the Kashmir basin was Blled with a massive glomerates (Bhatt 1975, 1976; Singh 1982). lake (Bgure 1b) and later on the lake boundary was Stratigraphically, Karewa Group is divided into pushed against the Himalayan Cank (Bgure 1c) due two formations namely, older Hirpur Formation to ongoing orogenic eAects of Pir Panjal mountain and younger Nagum Formation separated by an ranges (Godwin-Austen 1864; Lydekker 1878; angular unconformity (table 1) and the type sec- Drew 1975). The orogenically uplifted lake sedi- tion is exposed in Hirpur area. The Hirpur For- ments came to be known as Karewa Group mation has been divided into older Dubjan (Bgure 1d). The entire sedimentation in Karewa Member (600 m) followed by Rembiara Member Group is controlled by the tectonics (Burbank (200 m) and the top Methawoin Member (400 m) 1982; Burbank and Johnson 1983). About 1300-m (Bhatt 1989). The sedimentation in the Karewa thick Karewa Group is made of clays, sands with basin has been punctuated by conglomerate 93 Table 2. Vegetation type inCuenced by climate and tectonic changes in two units of Ningle Nala sedimentary section, Butapathri, Kashmir.

Early Pleistocene epoch (Lower Karewa Formation)

Unit 1 Unit 2 21 of 6 Page Assemblage type Phase 1 Phase 2 Phase 3 Phase 4 1. Warm temperate Alnus, Betula, Juglans, Quercus, Ulmus, Acer, 17.3 16 9.7 9.7 Fagus, Carpinus, Corylus, Larix, Salix 2. Cool temperate Pinaceae type 11.5 14.7 77.9 77 Abies pindrow, Abies sp., Cupressus, Juniperus, (Pinus Picea, Abie, 65%) Pinus roxburghii, P. wallichiana, Picea sp., Rhododendron 3. Rain forest Arboreal Pollen 3.7 2.7 (Rosaceae) 4 4 Ericaceae, Meliaceae, Ilex, Sapindus, Toona, All Palaquium, Caraya, Proteaceae, Rosaceae, Symplocos, Annonaceae, Prinsepia utilis, Turpinia, Mallotus, Randia, Malvaceae Shrubs/herbs 12.45 10.7 (Celastrus, Rubus, 3.1 – Ainsliaea latifolia, Anemone, Anthriscus Anthriscus, (Anemone, Asteraceae, caucalis, Asteraceae,Campanula, Celastrus, Chenopodiaceae, Chenopodi–aceae,

Chenopodiaceae, Chrysanthemum type, Asteraceae, Impatiens) Sci. Syst. Earth J. Clematis montana,Clematis puberula, Portulacacaeae) Desmodium Coribundum, Holmskioldia sanquinea, Impatiens, Ligustrum compactum, Liliaceae, Lonicera myrtillus, O. speciosa, Oenanthera linearis, Phoenix, Plantago, Portulacaceae, Streptopus simplex, Rhus parviCora, Rubus, Rumex, Silene, Taraxacum, Xanthium, Lonicera quinquilocularis (2021) 130:93 Aquatic 10.6 13.4 – 3.0 Lemna, Ludwigia, Nuphar, Persicaria Nuphar lapathifolium, Persicaria vaccinifolia, Potamogeton Aratisporites banksi, Cicatisporites, \0.01 –– – Fungal Spore 3.5 0.8 – 0.1 .ErhSs.Sci. Syst. Earth J. Table 2. (Continued.)

Early Pleistocene epoch (Lower Karewa Formation) Unit 1 Unit 2 Assemblage type Phase 1 Phase 2 Phase 3 Phase 4 4. Diatom –– – – C. cistula –– – + (2021) 130:93 C. proxima –– – – C. simonsenii –– – + Coconeis scutellum 8.6 8.8 – 10.9 Cymbella brehmii – 6.9 – + Cymbella lacustris 17.7 9.7 7.3 15.1 Diatoma vulgare 11.8 11.3 9.2 12.5 Ellerbeckia arenaria 7.5 7.3 10.5 15.4 Epithemia turgida 17 9.3 9.4 + Gomphonema acuminatum – 7.3 – + Stauroneis phoenicenteron 16.2 6.8 9.3 + Surirella ovalis 10.3 ––+ Tabellaria fenestrata ––12 –– Tetracyclus lacustris 7.1 18.9 + 5. Sponge Spicules –– – – Astrose forms 0.8 0.8 9 + Birrotule 4.7 14.1 –– Corvohetero meyenia –– – – Corvospongilla 13.5 – 11.9 + Dosilia plumosa 19.7 –13.2 15.9 + Ephydatia Cuviatilis 9 14.1 15.9 + Ephydatia meyeni –– – – Radiospongilla crateriformis 10.7 13.1 14.9 – S. loricatus 11 – 14.9 – Spongilla lacustris 16.3 15.2 –– Spongilla lacustris – 12.3 –– Trochospongilla variabilis 15 –– 21 of 7 Page + Stray presence of Palynomorphs, À Palynomorphs were not found in the studied macerals. 93 93 Page 8 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 8. Light microscopic photographs of pollen/spores comprising Ulmus (1); Juglans (2–4); Alnus (5 and 6); Betula nana (7); B. pubescens (8); Corylus (9); Carpinus (10); Quercus (11 and 12); Fagus sylvaticus (13); Acer (14); Rumex (15); Plantago (16); Salix (17); Silene (18); Phoenix (19); Cuppressoides (20 and 21); Juniperas (22); UnidentiBed (23); Pinus (24 and 25); Pinus roxburghii (26); P. wallichiana (27); Pinus (28); Abies pindrow (29); Abies (30); Picea smithii (31); Podocarpus (32); Rhododendron (33); Ericaceae (34); Ongoekia (35 and 36); Poaceae (37 and 38); Cyperaceae (39); Campanula (40); Taraxacum (41); Asteraceae (42 and 43); Mallotus (44); Solanaceae (45); Turpinia nepalensis (46); and Viola biCora (47). (All scales = 10 lm.) J. Earth Syst. Sci. (2021) 130:93 Page 9 of 21 93

Figure 9. Light microscopic photographs of pollen/spores of Prinsepia utilis (1); Clematis montana (2); Clematis puberula (3); Stranvaesia glaucescens (4); unidentiBed (5); Liliaceae (6); Ainsliaea latifolia (7); Anemone rupicola (8); Plantago (9); Caucalis anthriscus (10); Oenanthe linearis (11); Chenopodiaceae (12 and 13); Randia (14); Lonicera quinquilocularis (15); Malvaceae (16); Impatiens (17 and 18); Impatiens balsami (19); Impatiens racemosa (20); Nuphar (21); Lemna (22); Potamogeton (23); Ludwigia (24); Polygonum lapathifolium (25); Polygonum vaccinifolum (26); Myriophyllum (27); Symplocos (28); Annonaceae (29); Rosaceae (30 and 31); Celastraceae (32); Ranunculus (33); Proteaceae (34); Meliaceae (35); Toona ciliata (36); Palaquium ellipticum (37); Ilex (38); Ligustrum compactum (39); Caryophyllaceae (40); Portulacaceae (41); Rhus parviCora (42); Euphorbia (43); Desmodium Coribundum (44); Streptopus simplex (45); and Holmskioldia sanquinea (46). horizons at about 3.5–3.0, 2.7, 2.1 and 1.7 Ma Methawoin Member in the Hirpur Formation (Burbank and Johnson 1982). Two conglomerate (Bhatt 1989). Another stratigraphic section of beds (A and B) occur at about 200 m (Bed A) and Hirpur Formation is developed in the Ningle Nala 350 m (Bed B), respectively, above the base of near Gulmarg, where lower two members (Dubjan 93 Page 10 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 10. Light microscopic photographs of pollen/spores of Polypodium (1 and 2); Cyclosorus interruptus (3); Selaginella microspore (4); Lycopodium (5); Polypodiaceae (6); Asplenium (7); Polypodium juglandifolium (8); Asplenium alternans (9); Polypodium (10); Polypodium occulum (11); Gleicheniaceae (12 and 13); Adiantum (14–16); Adiantum venustum (17); Aspidium marginatum (18); Pteris subquinata (19); Pteridophytic spore (20); Lycopodium spore (21); Aratisporites banksi (22); and Cicatricosisporites (23). and Rembiara) are partly exposed (Bhatt 1989). Desai 1974; Singh 1982; Bhatt 1989). Here only a The depositional environments are Cuvioglacial, 75-m thick succession of lower part of Methawoin Cuvio-lacustrine and lacustrine (DeTerra and Member comprising of sand, sandy clay, clay and Patterson 1939; Wadia 1948, 1976; Farooqui and thinner bands of lignite is exposed (Singh 1982; J. Earth Syst. Sci. (2021) 130:93 Page 11 of 21 93

Figure 11. Algal/fungal spores of Botryococcus sp. (1); Botryococcus braunii (2); Anthoceros punctatus type (bryophytic spore) (3); Ascospores (4–9); Chlamydospore or conidium (10); Tetraploa (11); UnidentiBed (12); Ascospores (13–19); Nigrospora type (20); Papulospores (21–25); Tilletia (26); Mycrothyriaceous fungi (27–30); Basiodiospore type (31); non-septate branched spinate hyphae of basidiomycetes fungi (32); unidentiBed (33); Graminaceous epidermal cells along with stomata and short celled phytoliths (34 and 38); Phragmothyrite type (39–40). All scales=20 lm. 93 Page 12 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 12. Different diatom species of Ellerbeckia arenaria (Ralfs ex Moore) Crawford (1); Diatoma vurgare Bory de St. Vincent (2); Tabellaria fenestrata (Lyngbye) Kutzing (3); Tetracyclus lacustris Ralfs (4); Cymbella brehmii Hustedt (5); Cymbella simonsonii Krammer (6); Cymbella cistula (7); Cymbella proxima Reimer (6); Cymbella amphicephala var. bercynica (Schmidt) Cleve (9); Cymbella lacustris (Agardh) (10); Gomphonema acuminatum Ehr. (11 and 12); Cocconeis scutellum Ehrenberg (13); Sellaphora pupula (14); Stauroneis phoenicenteron (Nitzsch) Ehrenberg (15); Epithemia turgida (Ehr.) Kutzing (16); Diploneis smithii (Breb.) Cleve (17); Diploneis didyma (Ehrenberg) Cleve (18); Surirella ovalis Brebisson (19).

Bhatt 1989). Other lithounits of Lower Karewa and 2.3 ± 0.3 Ma (Kusumgar et al. 1985) have been (Methawoin Member) from Ningle, Baramulla and marked by Zircon Bssion track age of volcanic ash Rembiara sections have been studied earlier (Singh horizon at the top of Rembiara Member (Basava- 1982), but the vegetational record is scant. The iah et al. 2010). This ash is thought to have its two time-brackets as 2.4 ±0.3 Ma (Burbank 1985) source in Dacht-e-Navar volcanic complex in J. Earth Syst. Sci. (2021) 130:93 Page 13 of 21 93

Afghanistan (Johnson et al. 1982) and is also Acer, Pittosporum, Mallotus, Myrsine, Ficus, etc., recorded in Siwaliks (Bhat et al. 2008; Patnaik which is palynologically similar to bottom sedi- 2003). No ash or conglomerate bed was observed in ments of Unit I-phase 1 in the studied sec- the present studied lithosection exposed at Buta- tion. Hence, on the basis of chronology, texture and pathri (elevation 2796 m amsl, lat. 34°04027.700N, biotic proxy-records of lithounits in the present long. 74°18020.700E, covered under SOI survey sheet studied section is assigned to lower Methawoin no. 43J/6) area of Gulmarg, Kashmir (Bgure 1a). Member of Hirpur Formation. The conglomerate deposition took place during late Pliocene (*2.7 Ma) forming the top of Rembiara 2. Materials and methods section and subsequently an ash layer was deposited *2.4 Ma and further another conglomerate On the basis of lithological changes, 12 samples bed is reported at 2.1 Ma (Burbank 1985). Both the were collected from 8.5-m thick exposed nala-cut evidences are not observed in the studied section section at Butapathri (Gulmarg), where the bot- (Bgure 3) and therefore, we assign the studied tom and the topmost samples are numbered 1 and lithosection between 2.4 and 2.1 Ma with pollen 12, respectively (Bgures 2 and 3). evidences of tropical to subtropical climate. The conglomerate beds are known to have deposited during upliftment of Pir Panjal Mountain ranges 2.1 Pollen and spores inducing altitudinal rise and therefore the lower sedimentary section of Methawoin shows a For palynological study, 10 grams of sediment sequence of silty clay, clay, sand and intercalated samples were air-dried and processed following lignite layers having megafossils of Trapa fruit Erdtman (1943) and Halbritter et al. (2018). The (Bgure 2) deposited in mild Cuvial to lacustrine processed sample was made 5 ml by volume in 50% ecosystem. Bhatt (1989) reported lignite layers in glycerin medium. A drop of sample from this Methawoin Member about 30 m upsection from the homogenized aliquot was mounted on the glass contact with underlying Rembiara Member in the slides in glycerin jelly medium and the pollen/ Ningle Nala section. The only time marker horizon spores were counted ([200) which represents the in the upper part of Rembiara Member is the vol- pollen sum (Bgure 4). The pollen grains grouped in canic ash (2.4 Ma) in contact with younger ecological perspective constitute semi-evergreen Methawoin Member. As there is no ash layer and broad leaf deciduous vegetation acclimatized to conglomerate bed in an 8.5-m thick sediment, the warm-temperate climate. The conifers represent studied section is bracketed between 2.4 and 2.1 cold-temperate climate. The sub-tropical ever- Ma in the lower Methawoin Member. A compara- green/semi-evergreen represents low seasonality tive account of sedimentary sequences of Lower and high rainfall sub-tropical vegetation Karewas studied from different river-cut sections (strengthened ISM) at low altitudes. Poacaeae/ has been given in Bgure 3 in order to correlate the Cyperaceae pollen grains are meager and aquatic lithounits and micro-biotic remains with the pollen taxa are included in the pollen sum. The chronology of the dated Hirpur Formation. Singh reference slides in BSIP herbarium and standard (1982) studied the sedimentological characteristics literature such as Gupta and Sharma (1986) were of the sediments of Karewa Group at different referred for pollen identiBcation. For diatoms and localities in Kashmir and concluded that these sponge spicules, the sediment processing and slide sediments have been deposited in Cuvio-lacustrine preparations for analysis were performed following settings. the techniques described by Batterby (1986). The The palynoCoral record shows evidences of wil- results are the relative percentage of diatoms lows, alders, spruce, silver Br, blue pine, deodar, (Bgure 5) and sponge spicules (Bgure 6) each in 2 g etc., along with pollen of Nelumbo nucifera from of samples. The cumulative account of relative contemporary Ningle section at lat. 34°40, long. percentages of all the biotic proxy records includes 74°190 in Butapathri at an elevation of 3,200 m ‘total sum’ of pollen, diatoms, trilete/monolete amsl (Gupta 1992). However, nearby the Liddar- spores and freshwater sponge spicules (Bgure 7). marg Cora (lat. 33°480; long. 74°390) lies at an ele- The diatoms were identiBed using Round et al. vation of 3,500 m amsl and is blackish clay similar (2007). All the photographs were taken with to Ningle Nala sediment and is also composed of Olympus BX-51 (camera DP-26) microscope and tropical sub-Himalayan rainforest Cora such as graphical Bgures made in Tilia software (Grimm 93 Page 14 of 21 J. Earth Syst. Sci. (2021) 130:93

Figure 13. Fresh water sponge spicules comprising megasclere of Dosilia plumosa (1); Spongilla sp. (2); megasclere of Trochospongilla sp. (2–5); microsclere of Spongilla lacustris (Rosette of microspines) (6); Radiospongilla crateriformis – microsclere (7–9); R. crateriformis gammosclere (10 and 11); gammosclere Anheteromeyenia argyrosperma (12); gammosclere of Corvoheteromeyenia heterosclera (13); Spongilla loricata gammoscleres (14 and 15); Ephydatia Cuviatilis birotule gammoscleres with smooth and spiny oxeas (17); Ephydatia sp. gammoscleres (18 and 19); Trochospongilla variabilis gammosclere (Both the rotules turned outwords) (20); Ephydatia meyeni (21); Biorotule (22) microsclere of Dosilia (23); Nettle cell of Hydra (24); broken sponge spicule (25); and Astrose microsclere of Dosilia (26). J. Earth Syst. Sci. (2021) 130:93 Page 15 of 21 93

Figure 14. Schematic diagram of past and present Karewa basin modiBed after Valdiya 2001.

1987) and (CONISS) cluster analysis helped to with de-ionized water prior to measurements. broadly demarcate two climatic units (I and II) Microscopic inspection of selected samples was with four ecological phases (1À4). carried out to verify the successful removal of components that might create hindrance during the analysis. The grain size distributions were 2.2 MAT and MAP analysis determined using a laser diAraction particle size analyser Beckman Coulter LS I3 320 at the BSIP, For the quantitative reconstruction of temperature Lucknow, India. and precipitation, the coexistence approach (CA) of the vegetation cover was employed (Mosbrugger and Utescher 1997). The modern distribution of all 3. Results nearest living relative (NLR) taxa, which were used for the analysis was extracted from Champion The relative abundances of pollen/spores, diatoms, and Seth (1968), Hooker (1872–1897), Dar et al. sponge spicules and their statistical analysis (2014a, b), Blatter (1928À1929), Ara et al. (1995), revealed two distinct units of depositional envi- and Singh et al. (1998) in relation to their geo- ronment. Unit I comprised of phases 1–2 and Unit graphic distribution. The climatic tolerance of the II comprised of phases 3–4. The climatic variations species was determined from the Climatological have been inferred in terms of temperature (MAT) Tables of Observatories in India (1931–1960) and precipitation (MAP) variation in each of these which contains the climatological normal data of 30 units (table 3). Whereas, the depositional envi- years taken from 235 climate stations distributed ronment and the ecology of the ecosystem are all over the country. Six parameters of temperature explained in detail with the help of sediment tex- and precipitation were estimated, i.e., MAT = ture, pollen/spores, diatoms and freshwater sponge mean annual temperature, WMT = warmest mean spicules. The details are given below. The pho- temperature of the month, CMT = coldest mean tographs of biotic forms used in the study are temperature of the month, MAP = mean annual provided in Bgures 8–13. precipitation, HMP = humid mean precipitation of the month, and LMP = lowest mean precipitation 3.1 Unit I of the month (table 3). Phase 1: Total percentage of thermophillous broad 2.3 Grain size analysis leaf pollen taxa is 17.3 comprising 12% of Alnus, Betula, Ulmus, Quercus and Juglans (Bgure 4) and A total of 10 samples were selected (leaving two 5.3% of Corylus, Carpinus, Salix, Larix, Acer and lignite sample numbers 5 and 9) to study grain size Fagus. Out of the total count, the cool temperate distributions of the detritus fraction (Bgure 5). pollen taxa constitute 11.5% that include Cupres- About 3–5 g of sample was taken in 50 ml cen- sus, Juniperus, Pinus roxburghii, P. wallichiana, trifuge tube. Calcium carbonate and organic Picea sp., Abies sp., Abies pindrow, and Rhodo- material were removed with acetic acid and dendron (table 2). Out of these, 19.8% constitute hydrogen peroxide (10%), followed by a triple rinse the pollen of rainforest. The arboreal pollens (AP) 93 Page 16 of 21 J. Earth Syst. Sci. (2021) 130:93 constitute 3.7% (table 2). The shrubs and herbs Birotules include about 14.1% and Astrose type to constitute 12.45%. The aquatic pollen and fungal 0.8%. spores constitute 10.6% of the total count and among these are Nuphar with highest percentage (5.5) followed by Persicaria lapathifolium (2.2%), 3.2 Unit II and Persicaria vaccinifolia (2.0%). Others like Lemna, Potamogeton, and Ludwigia constitute Phase 3: Total percentage of broad leaf warm *0.8% and fungal spores show low percent (0.4). temperate (thermophillous) pollen taxa is rela- Stray presence of the Pliocene palynomorphs tively quite low (9.7). These are in low diversity (\0.01%) such as Cicatisporites and Aratisporites and comprise of only Alnus, Ulmus and Juglans. banksi (Bgure 10) were recorded in the bottom Out of the total count, the cooler temperate pollen sediments along with 3.5% of diverse fungal spores taxa constitute 77.9% dominated by Pinaceae (Bgure 11) out of total count of pollen/spores family. About 3.1% constitute the sub-tropical (Bgure 7). herbaceous pollen such as Anemone, Chenopodi- Seventeen diatom species were recorded, but aceae, Impatiens and Asteraceae. The aquatic most of these were broken frustules that could be pollens constitute 14.6% of the total count. identiBed. The highest percentage was of Cymbella A high percentage of diatoms (Bgure 5) comprised lacustris (17.7) and Stauroneis phoenicenteron of Tetracyclus lacustris (18.9%), Epithemia turgida (16.2) followed by Diatoma vulgare (11.8), Surirella (9.4%), Ellerbeckia arenaria (10.5%), Stauroneis ovalis (10.3), Coconeis scutellum (8.6%), Tetracy- phoenicenteron (9.3%), Diatoma vulgare (9.2%) and clus lacustris (7.1) and Ellerbeckiaarenaria (7.5). Cymbella lacustris (7.3%) was recorded. The rest Rest 17% constituted Epithemia turgida, Gom- comprised ranging from 0.4 to 5% (table 2). phonema acuminatum, Cymbella brehmii, C. prox- In this phase, the dominant freshwater sponges ima, C. simonsenii and C. cistula ranging between are Ephydatia Cuviatilis (15.6%), Ephydatia meyeni 1 and 4% (Bgure 12). (15.9%), Spongilla lacustris (14.9%), Dosilia plu- Nine species of freshwater sponges (Bgures 6 and mosa (11.9%), and Spongilla loricatus (9.6%). The 13) were unidentiBed. The dominant forms con- rest 23% constitute four species. About 9.0% of stitute Dosilia plumosa (19.7%), Corvospongilla Birotules were recorded. (13.5%), Spongilla lacustris (16.3%), S. loricatus Phase 4. Total percentage of broad leaf ther- (11.0%) and Radiospongilla crateriformis (10.7%). mophillous pollen taxa is 9.7. Out of the total count, Other species given in table 2 were also recorded. the relative percentage of cool temperate pollen was Phase 2. The total percentage of thermophillous high (77%). The only aquatic pollen Nuphar con- broad leaf pollen is 16.0. The cool temperate pollen stitutes 3.0% and fungal spores account to 0.1%. constitutes 14.7%. About 12.7% constitute the sub- The dominant diatom forms were Ellerbeckia tropical evergreen to semi-evergreen rainforest pol- arenaria (15.4%), Cymbella lacustris (15.1%), Di- len that are relatively less diverse than in Phase 1. atoma vulgare (12.5%), Coconeis scutellum (10.9%) The aquatic pollen and fungal spores constitute and Epithemia turgida (9.4%). Rest *37% com- 13.4% of the total count. The fungal spores were prised of nine species (table 2). In this phase, the low (0.8%). The dominance of Tetracyclus lacus- freshwater sponges, which show less diversity both tris (12%) and Diatoma vulgare (11.3%) was quantitatively as well as qualitatively constitute recorded. Other species given in table 2 were also four species. recorded in a range from 7 to 9%. Other minor percentages of seven species (table 2) constitute 3.3 Grain size *20%. The total count of freshwater sponges shows Broadly, Unit I and Unit II of sediment deposi- about nine identiBable species (Bgure 6) on the tional environment were recorded with two inter- basis of gammoscleres and some unidentiBed forms. mittent sandy layers (Bgure 2). The average sand, The dominant forms are Spongilla lacustris silt and clay percentage was 28.9, 63.6 and 7.4, (15.2%), Ephydatia meyeni (14.1%), Ephydatia respectively, in Unit I-phase 1 (Bgure 5). An abrupt Cuviatilis (13.2%), Spongilla loricatus (13.1%), and increase of 62% of sand in phase 2 of Unit I com- Trochospongilla variabilis (12.3%). Rest four spe- prised only 22% of silt and clay followed by a layer cies constitute 18% of the total count. The of coal/lignite deposit showing abundance of Trapa J. Earth Syst. Sci. (2021) 130:93 Page 17 of 21 93

fruits as megafossils (Bgure 2). Subsequent to this, 83% of reduction in sand was recorded with an increase in percentage of silt in Unit II, phase 3. A P: Humid sandy layer in Unit II-phase 4 with decrease in silt and clay followed by a thin lignite layer which was again bearing fossilized Trapa fruits was recorded. The highest percentage of silt was recorded in phase 4 with the lowest sand percentage. Overall biotic and sediment texture indicates that the lake transformed from deeper to shallower bathymetry.

4. Discussion

The three orogenic activities in the Kashmir region are Karakoram, Simurian and Siwalikian phase during Middle Cretaceous, Oligocene–Miocene and late Pliocene to Middle Pleistocene, respectively (De Terra 1934). The Karewa Formation is one of the sedimentary sections that was deposited during late Pliocene–Pleistocene epoch inCuenced by orogenic activity of the Pir Panjal mountainous range in the south of Karewa basin playing a crucial role in monsoon regulation in the region. Sahni (1936) and Valdiya (2001) opined that the Karewa lake- bed Formation in Gulmarg–Baramulla occurred at lower altitude several 100 m lower than present and was never at an altitude where it is found at C) MAP (mm) HMP (mm) LMP (mm) ° present (Bgure 14). The sedimentary record in the Hirpur Formation shows that the sedimentation started within an extensive lake basin during lower part (Dubjan Member) followed by a major regressive phase during which Rembiara Member Conglomerates were deposited (Singh 1982) possi- bly due to orogenic upliftment around Neo- 2.75 19.6 25.6 22.6 373 1206 789.5 44 143 93.5 93.5 8 31.5 1.85 17.5 28.3 22.9 422 1162 792gene 217–Quaternary 143 180 180 boundary. 45 615.5 This was followed by – – tectonic quiescence up to 1.95 Ma (Basavaiah et al. C) WMT ( ° 2010) which resulted into a transgressive phase

C) and precipitation (mm) based on vegetation succession Lower Karewas. after 2.4 Ma leading to the deposition of Metha- ° woin Member. Singh (1982) while working on the sedimentological characteristics of Karewa sedi- 13.3 7.8 11.5 7.8 13.3 15.6 15.6 17.5 28.5 23 373 1162 767.5 217 293 255 255 8 26.5 – – – ments concluded that the Methawoin Member was deposited primarily in a shallow lake that was fed by major river system which built up birdfoot type delta system with numerous distributaries into the C) CMT (

° lake. The thin lignitic mud was deposited in the swamps developed along the margin of the lake. MAT ( Min Max Average Min Max Average Min Max Average Min Max Average Min Max Average Min Max Average Estimated atmospheric temperature ( 4.1 Unit I

The studied section is the lower Methawoin member Zone Table 3. 1Note. MAT: Mean annual temperature;months CMT: mean Coldest precipitation months 18.5 (monsoonal); mean temperature; LMP: WMT: Lowest Warmest month months mean mean 16.1 temperature; precipitation MAP: (post-monsoonal). Mean annual precipitation; HM 17.3 13.1 13.1 13.2 24.9 25.6 25.25 996 1053 1024.5 217 293 293 255 8 26.5 2 0 16.1 8.05 3 4.4 16.1 10.25 4 0 21.7 10.85 (youngest sedimentary unit of Lower Karewa Basin) 93 Page 18 of 21 J. Earth Syst. Sci. (2021) 130:93 bracketed between 2.4 and 2.1 Ma. The top of the 4.2 Unit II Rembiara section below the Methawoin member is marked by ash layer dated 2.4 Ma and conglomerate The Unit II shows a drastic reduction in the sub- bed in the Methawoin Member. Hence, the studied tropical vegetation to 0.2% along with other biotic section is bracketed as lower part of Methawoin forms, such as temperate pollen (28.9%), herbs/ Member as both the marker beds of ash and con- shrubs (7.8%), aquatic pollen (8.9%), fern spores glomerates are not present in the section. The earlier (6.6%) and sponge spicules (4.6%). A significant records of fossil (plant remains) from contemporary increase of diatoms by 43.0% in relation to other Gulmarg–Baramulla region (Middlemiss 1911; biotic forms was observed. An overall dominance of Wodehouse and de Terra 1935; Sahni 1936; Puri diatom such as Tetracyclus lacustris suggests 1948) revealed low-level lake basin in milder climate. lacustrine depositional environment in cool climate Our results are in conformation with the above as as these are reported from freshwater sediments in out of the total count, Unit I revealed 4.6% of sub- acidic lacustrine conditions mainly limited to tropical taxa (Ilex, Sapindus, Toona, Palaquium, northern/alpine region (Round et al. 2007). Earlier, Careya, Proteaceae, Rosaceae, Symplocos, Turpinia Mohan and Vora (1987) recorded Tetracyclus and Mallotus, etc.), 39.5% of sub-Himalayan to japonica from the contemporary Karewa beds. Alpine forests, 16.8% of herbs/shrubs, 14.7% of Other records of freshwater diatom assemblages aquatic vegetation (Nuphar, Lemna, Potamogeton, from the Lower Karewa beds in the Kashmir valley Ludwigia, Persicaria lapathifolium and Persicaria also indicate cold climate and lacustrine environ- vaccinifolia), 11.2% of fern spores, 7.4% of diatoms ment (Gandhi et al. 1986; Gupta and Khandelwal and 5.6% of sponge spicules. The quantitative data 1986). An increase in Pinaceae pollen also supports a thus reveals more terrestrial sediment inCux during rise in altitude and cooler climate. Thus, it is inferred milder climate with 17°C (MAT) and 1000 mm that during this time period, the climate had ame- (MAP) indicating strengthened Indian Summer liorated from warmer to cooler climatic conditions Monsoon (ISM) in the region. Evidence of Impatiens with a sharp decline in MAT (*10°C) and MAP pollen in Unit I indicate frost-free winters (Ellenberg (760 mm). Very Bne grain sediments during this 1988). Similar biotic assemblages such as the broken phase also support low clastic from nearby drainage diatom frustules and sub-tropical pollen taxa along system. The phase 4 in Unit II shows a very scant with the aquatic pollen were recorded in muddy record of biotic forms in the Bne textured layers of sediments (Gupta and Khandelwal 1986) along the sediment. Very low occurrence of diatoms and Rembiara river in southern area above the volcanic aquatic pollen during this phase relates to shrinking ash (dated 2.4 Ma). The studied Ningle section also of a swampy ecosystem. The sponge spicules too shows similar abundances of identiBable broken reduced in percentage. Similar sequence of deposi- frustules of diatoms and tropical pollen taxa along tional environment and vegetation succession has with broadleaf temperate plants in Unit I. The been recorded from the Palaeo-Kathmandu Lake gammoscleres derived from the sponge gammules that perhaps initiated at around 2.1 Ma and was are known to form in the scarcity of water during its Blled with black organic mud, the Kalimati Clay life-cycle (Pronzato et al. 1993; Manconi and Pron- (Fujii and Sakai 2002). Therefore, it is inferred that zato 1994) indicates seasonality in climate which is the legacy of rainforest which began during Palaeo- analyzed by MAT where the mean coldest month gene inCuenced by dominance of monsoon system in was 138C. Therefore, low seasonality (7À8 months of the Indian sub-continent existed until *2.0 Ma in rainfall in a year) with moderate temperature was the Kashmir valley. This is in conformation with the supporting low altitude sub-tropical rainforest veg- palaeomagnetic data (Basavaiah et al. 2010) and etation in Unit I, phase 1 which tends to decline palynological/biotic evidences buried in Karewa Formation, Kashmir basin. gradually in phase 2. Earlier records also reveal that the Kashmir valley and the Pir Panjal mountain range in the south were of low altitude between 2.4 and 2.1 Ma (DeTerra and Paterson 1939; Wadia 5. Conclusions 1948; Kotlia 1985). The moist climate and low altitude of this stage are also attested by the prevalence The late Pliocene–early Pleistocene record of of primitive Elephas hysudricus, hippopotamus, *80 plant species, abundant fungal and algal bovids and crocodiles (Patnaik and Nanda 2010). spores, 18 diatom species and 7 freshwater sponge J. Earth Syst. Sci. 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