J. Earth Syst. Sci. (2017) 126: 25 c Indian Academy of Sciences DOI 10.1007/s12040-017-0809-z

Permian macro- and miofloral diversity, palynodating and palaeoclimate implications deduced from the coal-bearing sequences of Singrauli coalfield, Son– Basin, central

Kamal Jeet Singh, Srikanta Murthy, Anju Saxena∗ and Husain Shabbar Birbal Sahni Institute of Palaeosciences, 53, University Road, Lucknow 226 007, India. ∗Corresponding author. e-mail: anju [email protected]

The coal-bearing sequences of Barakar and Raniganj formations exposed in Bina and Jhingurdah open-cast collieries, respectively, are analysed for their macro- and miofloral content. The sediment suc- cessions primarily comprise of sandstones, shales, claystones and coal seams. In addition to the diverse glossopterid assemblage, four palynoassemblage zones, namely Zones I and II in Bina Colliery and Zones III and IV in Jhingurdah Colliery, have also been recorded in the present study. The megafossil assemblage from the Barakar strata of Bina Colliery comprises of three genera, namely Gangamopteris, Glossopteris and cf. Noeggerathiopsis. Palynoassemblage-I is characterised by the dominance of non-striate bisac- cate pollen genus Scheuringipollenites and subdominance of striate bisaccate Faunipollenites and infers these strata to be of Early Permian (Artinskian) age (Lower Barakar Formation). The palynoassemblage has also yielded a large number of naked fossil spore tetrads, which is the first record of spore tetrads from any Artinskian strata in the world and has a significant bearing on the climatic conditions. The palynoassemblage-II is characterised with the dominance of Faunipollenites over Scheuringipollenites and is indicative of Kungurian age (Upper Barakar Formation). The megafossil assemblage from the Raniganj Formation of Jhingurdah Colliery comprises of five genera with 26 species representing four orders, viz., Equisetales, Cordaitales, Cycadales and Glossopteridales. The order Glossopteridales is highly diversi- fied with 23 taxa and the genus Glossopteris, with 22 species, dominates the flora. The mioflora of this colliery is represented by two distinct palynoassemblages. The palynoassemblage-III is correlatable with the palynoflora of Early Permian (Artinskian) Lower Barakar Formation. The assemblage suggests the continuity of older biozones into the younger ones. The palynoassemblage-IV equates the beds with com- position V: Striatopodocarpites–Faunipollenites–Gondisporites assemblage zone of Tiwari and Tripathi (1992) of Late Permian (Lopingian) Raniganj Formation in Damodar Basin. The FAD’s of Alisporites, Klausipollenites, Falcisporites, Arcuatipollenites pellucidus and Playfordiaspora cancellosa palynotaxa in this assemblage enhance the end Permian level of the Jhingurdah Top seam, as these elements are the key species to mark the transition of Permian into the Lower Triassic.

1. Introduction in the states of and . The coalfield has 10 opencast collieries The Singrauli coalfield lies in the north-western of which coal-bearing sequences of nine collieries part of Son–Mahanadi Master Basin and spreads (Dudhichua, Jayant, Kakri, Bina, Krishnashilla,

Keywords. Macroflora; Palynology; Barakar; Raniganj; Permian; Singrauli coalfield.

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Amlohri, Khadia, Block B and Nigahi) belong to 2. Geology of the area the Barakar Formation, whereas Jhingurdah Col- liery is in Raniganj Formation. All the nine col- The Singrauli coalfield (figure 1) lies at the lieries of Barakar Formation have three coal seams, northern-most boundary of the Son–Mahanadi i.e., the lowermost Turra seam, middle Purewa bot- Master Basin that stretches from the east coast tom and the uppermost Purewa top coal seam. to the centre of Peninsular India. This coalfield Jhingurdah Colliery situated in the north-eastern embodies the last deposits of the Gondwana sedi- part of Singrauli coalfield has two coal seams, Jhin- mentation. Therefore, no sediments of Gondwana gurdah Top and Jhingurdah Bottom. It has the period occur beyond this coalfield area in the northern part of Peninsular India. It lies between thickest coal seam (Jhingurdah) in India (130 m). ◦ ◦ ◦ ◦ The Talchir Formation is mostly exposed in the latitudes 23 47 –24 12 and longitudes 81 48 –82 52 northern and eastern parts of the coalfield. and is located in the drainage area of Son and Rihand rivers. The total geographical area of this In comparison to the other coalfields of the coalfield is around 2200 km2; approximately 80 km2 Son–Mahanadi Basin, the Singrauli coalfield has not comes in the of Uttar Pradesh received much attention as far as the macrofloral State, and the rest fall in of studies are concerned. However, the coalfield has Madhya Pradesh State. been well investigated for its palynological (bore- The coalfield is structurally divided into two core data) and petrological aspects in the past by tectono-sedimentary sub-basins: (i) Moher sub- many workers (Trivedi 1950; Pareek 1969, 1970; basin on the north-eastern side and (ii) the Sin- Tiwari 1969, 1971; Sinha 1969, 1972; Bharadwaj grauli main sub-basin to the west. There is no and Sinha 1969a, b; Tiwari and Srivatsava 1984; clear cut demarcation between these two sub- Tiwari and Ram-Awatar 1989; Mishra and Singh basins because all the Lower Gondwana formations 1990; Singh and Mishra 1991; Vijaya et al. 2012; are exposed uninterruptedly in these sub-basins. Singh and Singh 2014; Saxena et al. 2016a). Bar- The sediments of Permian representing Talchir, ring the initial investigations by Lele (1966) and Barakar, Barren Measures and Raniganj forma- Lele et al. (1968) who reported the glossopterid tions are extensively exposed in the Moher sub- mega plant fossils in the Talchir and Barakar sedi- basin, whereas the Triassic sediments belonging to ments exposed in the eastern part of the coalfield, Panchet (Pali) and Mahadeva (Parsora) formations and the comprehensive morphotaxonomic studies are mainly confined to the Singrauli main sub- carried out on Raniganj Formation of the Jhingur- basin. The only difference between both the sub- dah Colliery (Singh and Saxena 2015) and on the basins lies in the number of coal reserves found Barakar Formation of Bina Colliery (Saxena et al. in them. All the ten working opencast mines of 2016b), no other megafloral studies have been Singrauli coalfield, viz., Dudhichua, Jayant, Kakri, attempted so far. Bina, Krishnashilla, Amlohri, Khadia, Block B, The aim of the present communication is to Nigahi and Jhingurdah come under Moher sub- ascertain the palynostratigraphic status and age basin. Barring Jhingurdah, the rest of the col- of the studied strata and to envisage the signifi- lieries are in Barakar Formation and have three cant changes in floral composition, and associated coal seams, i.e., the lowermost Turra seam, middle climatic conditions responsible for the floristic evolu- Purewa bottom and the uppermost Purewa top. tion through the Permian time in Singrauli coalfield All these seams reserve good quality of coal. The based on the macro- and miofloral investigations. Barakar sediments mainly consist of medium to To address this issue, the macrofloral and palyno- coarse grained, light grey, feldspathic sandstones, logical observations derived from the Barakar and shales, clays and coal seams. Jhingurdah Colliery Raniganj sediments of Bina and Jhingurdah col- is in Raniganj Formation and has the thickest coal lieries have been taken into consideration. Detailed seam (134 m) in India. It also has the deepest systematic descriptions of the megafloral assem- basinal area among all other collieries of this coal- blages of both the collieries have already been pub- field. The Raniganj sediments consist of medium to lished elsewhere (Singh and Saxena 2015; Saxena coarse-grained sandstone, grey shale, carbonaceous et al. 2016b: Singh et al. 2016). Herein, the dataset shale, claystone and coal seams. of these recently analysed megafloral assemblages, Based on the surface and subsurface data acquired studies based on the macrofloral remains of the so far, the generalised stratigraphic succession deve- Talchir and Barakar outcrops of loped in the Singrauli coalfield is given in table 1. (Lele 1966; Lele et al. 1968) and the present palyno- logical investigations on the different coal seams of both these collieries are used to decipher the grad- 3. Material and methods ual and gradational changes in mega and miofloral composition and development of Glossopteris flora The material described and discussed in this paper throughout the Permian in this coalfield. comprises megafossils and palynological samples J. Earth Syst. Sci. (2017) 126: 25 Page 3 of 16 25

Figure 1. Location map of Singrauli coalfield showing Bina and Jhingurdah collieries (after Raja Rao 1983). collected from the Barakar and Raniganj formations horizons and respective lithologs are shown in of Bina and Jhingurdah collieries, respectively. figures 2 and 3. The plant fossil assemblage of Bina Colliery is Well-preserved plant macrofossils were procured recorded from its Purewa Bottom and Turra coal from the grey shale and mudstone units of a seams. The Purewa bottom seam has yielded good coal-bearing sequence, viz., Jhingurdah Top seam fossil assemblage, whereas from the Turra seam, belonging to Raniganj Formation (Lopingian) from only rootlets are procured. For the palynologi- the Jhinguirdah Colliery and includes impres- cal analyses, three samples (BC/TS-0, BC/TS-1 sions of leaves, equisetalean axes and in-situ pre- and BC/TS-2) were collected from a section of served roots. The photograph of the section and the Turra Seam and another set of three samples corresponding lithology containing Glossopterid (BC/PB-1, BC/PB-2 and BC/PB-3) were collected remains, stems and in-situ preserved Vertebraria from the Purewa Bottom seam. The fossiliferous roots along with palynological samples are shown 25 Page 4 of 16 J. Earth Syst. Sci. (2017) 126: 25

Table 1. General stratigraphic succession of Singrauli coalfield (after Vijaya et al. 2012). Age Formation/group Thickness General lithology Recent Alluvium Cretaceous Basic intrusive Dolerite dykes and sills Late Triassic Parsora (Mahadeva) 500 m+ Medium-to-coarse grained ferruginous quartzose sandstone Early Triassic Pali (Panchet) 700 m+ Greenish yellow to reddish yellow, medium-to-coarse grained sandstone with variegated siltstone and clay Late Permian Raniganj 215–400 m Fine-to-medium grained dirty to buff coloured subarkosic to feldspathic wacke with alternation of thin lamination of grey and carbonaceous shale along with impersistent coal seams Middle Permian Barren Measures 110–300 m Dark brown to brownish yellow to greenish grey, medium-to-coarse grained flaggy sandstone with thin grey clay bands in between Early Permian Barakar 325–550 m Dirty white fine-to-coarse grained sub-arkosic to arkosic sandstone along with siltstone, shale, carbonaceous shale and coal seams Early Permian Talchir 75–230 m Dark greenish grey to grey shale, fine grained sandstone diamictite, siltstone pebbly sandstone and boulder bed Unconformity Precambrian Mahakoshal Granite, gneiss, quartzite, phyllite, schist and pegmatite

in figure 4. Three palynological samples (JC/JB-1, prepared and pollen spores were observed under JC/JB-2, JC/JB-3) were collected from the Jhin- the transmitted light microscope (Olympus-BX- gurdah Bottom coal seam and two palynological 61); the photographs were taken using Digital samples (JC/JT-1, JC/JT-2) were collected from Olympus camera (DP-20). Jhingurdah Top coal seam (figure 4). Based on the quantitative and qualitative rep- For the megafloral analysis, around 215 specimens resentation of the palynomorphs, different paly- were studied and identified up to genus and noassemblages are identified which are correlated species level. Their morphotaxonomy and detailed with the standard assemblage zones established description have already been dealt (Singh and by Tiwari and Tripathi (1992) and further the Saxena 2015; Saxena et al. 2016b; Singh et al. age bracket assigned by the GSSP sections to the 2016), wherein the combined data set of both the Permian Period as correlated and discussed by collieries is used to assess the change in floral Mukhopadhyay et al. (2010) for the interbasinal composition through the Permian. correlation of different formations in Indian Gond- For the palynological analyses, sediments are wana basins. A Late Palaeozoic portion of the processed using standard maceration technique. stratigraphic correlation chart and respective ages Each sample, weighing 50 g of sediments, was based on Mukhopadhyay et al. (2010) is given in crushed and treated with 40% hydrofluoric acid table 2. for 3–4 days to remove silica material, and then followed by treatment with nitric acid for 5–6 4. Megafloral observations days for digestion of humic matter. Thereafter, they were treated with 5% potassium hydrox- 4.1 Talchir megafloral assemblage ide to release all the humus. The macerals were mounted on the slides using polyvinyl alcohol and The floral composition recovered from the Talchir Canada balsam. Five slides from each sample were Formation (Early Permian = Asselian–Sakamarian) J. Earth Syst. Sci. (2017) 126: 25 Page 5 of 16 25

Figure 2. (a) Photograph showing measured section of a part of Turra Seam, Bina Colliery, Singrauli coalfield. (b)Litho- column depicting different lithounits of a part of Turra Seam. ∗ indicates the position of palynological samples.

Figure 3. (a) Photograph of the section of a part of Purewa Bottom coal seam of Bina Colliery depicting megafossil and palynological horizons. (b) Litholog of the section yielding megafossil and palynological assemblages. 25 Page 6 of 16 J. Earth Syst. Sci. (2017) 126: 25

Figure 4. (a) Panoramic view of Jhingurdah Top coal seam of Jhingurdah Colliery, ‘star’ indicates the position of figure 4(b). (b) Photograph of the section yielding megafossil and palynological assemblages. (c) Generalised litholog of the section of Jhingurdah Top coal seam. Star indicates megafossil-bearing horizons and triangle mark denotes the position of palynological samples.

Table 2. Correlation of Late Palaeozoic Gondwana basins (after Mukhopadhyay et al. 2010).

has revealed the occurrence of Noeggerathiopsis– 4.2 Barakar megafloral assemblage Gangamopteris assemblage (Lele 1966; Lele et al. 1968). The flora is completely devoid of the genus The megafossil assemblage recovered from the Glossopteris.ThetaxonNoeggerathiopsis hislopii coal-bearing sequence of the Barakar Formation is the most abundant element followed by Gang- of Bina Colliery is mostly represented by leaves amopteris cyclopteroides, G.cf.major and Gang- belonging to three genera, namely Gangamopteris, amopteris sp. Besides, seeds of Samaropsis cf. S. Glossopteris and cf. Noeggerathiopsis. Among these, goraiensis and stem casts were also reported in the the genus Glossopteris dominates with eight species Talchir assemblage (table 3). namely, Glossopteris browniana, Glossopteris cf. J. Earth Syst. Sci. (2017) 126: 25 Page 7 of 16 25

Table 3. A list of complete megafossil assemblages recovered from Talchir, Barakar and Raniganj formations of Singrauli coalfield. ∗ Talchir Formation Barakar Formation Raniganj Formation

Gangamopteris cyclopteroides *Gangamopteris cf. G. angustifolia McCoy Paracalamites sp. Zalessky Feistmantel (1876) (1875) G.cf.G. major *G. cyclopteroides Feistmantel (1876) Euryphyllum sp. Feistmantel (1879) Feistmantel (1879) *G. cyclopteroides var. areolata Gangamopteris sp. McCoy Feistmantel (1879) Macrotaeniopteris cf. M. feddenii (1847) Gangamopteris sp. Feistmantel (1876) Noeggerathiopsis hislopi Glossopteris browniana Brongniart (1828) (Bunbury) Feistmantel *Glossopteris communis Feistmantel (1876) Glossopteris angustifolia Brongniart (1879) G.cf.G. cordatifolia Feistmantel (1890) (1828) Samaropsis cf. S. goraiensis *G. indica Schimper (1869) G. arberi Srivastava (1956) Surange and Lele (1957) G. gigas Pant and Singh (1971) G. barakarensis Kulkarni (1971) Stem casts G. leptoneura Bunbury (1861) G. browniana Brongniart (1828) G. nakkarea Chandra and Surange (1979) G. communis Feistmantel (1879) G. pantii Chandra and Surange (1979) G. conspicua Feistmantel (1881) G. recurva Pant and Singh (1974) G.cf.G. cordatifolia Feistmantel (1890) *G.sp.cf.taeniopteroides G. gigas Pant and Singh (1971) G. tenuifolia Pant and Gupta (1968) G. giridihensis Pant and Gupta (1971) Glossopteris sp. G. gondwanensis Pant and Gupta (1971) cf. Noeggerathiopsis sp. G. indica Schimper (1869) G. karharbariensis Chandra and Surange *Samaropsis sp. G¨oeppert (1864) (1979) *Cordaicarpus sp. Geinitz (1862) G. linearis McCoy (1847) G. mohudaensis Chandra and Surange ∗Coniferous shoot (?Buriadia) (1979) ∗Equesetalean stem G. nimishea Chandra and Surange (1979) ∗Notched leaf G. oldhamii Pant and Singh (1974) G. stenoneura Feistmantel (1881) Rooting structures G. stricta Bunbury (1861) Stem casts G. subtilis Pant and Gupta (1971) Stem axes (impression) G tenuifolia Pant and Gupta (1968) Bifurcating/branching axes G. zeilleri Pant and Gupta (1968) Seeds Glossopteris sp. Brongniart (1828) Scale leaf Vertebraria indica Royle (1839) Fertile structures Ruptured/assorted meshes Thin slender axes Stem axes Root branches

Note. ∗ indicates contributions from Lele (1966).

G. cordatifolia, G. gigas, G. leptoneura, G. nakkarea, A close examination of the entire Barakar G. pantii, G. recurva and G. tenuifolia,whereasthe assemblage reveals the dominance of Glossopteris remaining genera are represented by one species over the genus Gangamopteris.Moreover,the each (table 4, figure 5). Many ill-preserved impres- leaves of Glossopteris are fairly medium to large sions representing scale leaves, seeds, fertile struc- in size (1.9–14.8 cm in length and 1.2–5.3 cm in tures, branching axes/roots and stem casts have width) and mostly are middle to broad mesh forms. also been found in this assemblage. In addition The flora is devoid of the groups lycopodiales, to Bina flora, Lele et al. (1968) had also reported filicales, sphenophyllales, cycadales and gingkoales. the presence of Gangamopteris cf. G. angustifo- lia, G. cyclopteroides, G. cyclopteroides var. are- 4.3 Raniganj megafloral assemblage olata, Glossopteris communis, G. indica, G.sp. cf. G. taeniopteroides and seeds of Samaropsis Complete flora of Raniganj Formation, as recovered and Cordaicarpus. A coniferous shoot (?Buriadia) from the Jhingurdah Top seam of Jhingurdah Col- and few equisetalean axes were also reported in this liery, consists of five genera with 26 species represen- assemblage (table 3). ting four orders, viz., Equisetales (Paracalamites), 25 Page 8 of 16 J. Earth Syst. Sci. (2017) 126: 25

Table 4. Relative percentages of various Glossopteris species Coniferales are completely missing in the Raniganj recovered from Raniganj Formation of Jhingurdah Col- Formation of this coalfield. liery (dominant: >10%; sub-dominant: 4–10%; rare: 2–4%; extremely rare: 0–2%). 5. Palynological observations Name of Sl. no. Glossopteris species Percentages The yield of palynomorphs in the samples is rich. Dominant In addition to this, palynodebris such as cuticle, 1 G. sp. 24.09 wood flinters, structured and unstructured organic 2 G. tenuifolia 14.45 materials and amorphous matter are also present. Sub-dominant The preservation of palynomorphs is fair to good. 3 G. nimishea 8.43 Based on the qualitative and quantitative analyses 4 G. arberi 7.22 of the spores and pollen taxa, four distinct paly- 5 G. communis 6.02 noassemblages have been identified in the Barakar 6 G. stricta 4.81 and the Raniganj formations (two in each forma- 7 G. browniana 4.81 tion) (table 5). The relative occurrences of the taxa Rare vary from rare (less than 1%), common (1–5%), 8 G.cf.G. cordatifolia 3.61 fair (5–10%) to abundant (11–25%) and to domi- 9 G. stenoneura 3.61 nant (>25%) in an assemblage (figure 7, frequency 10 G. indica 3.61 chart). The details of each palynoassemblage are 11 G. barakarensis 2.4 given below and the important palynotaxa are 12 G. giridihensis 2.4 shown in figures 7 and 8. 13 G. zeilleri 2.4 14 G. linearis 2.4 5.1 Palynoassemblage I Extremely rare 15 G. karharbariensis 1.2 Sample nos. BC/TS-0, BC/TS-1 and BC/TS-2 16 G. angustifolia 1.2 from Turra coal seam. 17 G. oldhamii 1.2 All the three samples have yielded very rich 18 G. mohudaensis 1.2 assemblage of the palynomorphs. An unusual 19 G. gondwanensis 1.2 occurrence of naked spore tetrads was recorded in 20 G. subtilis 1.2 the sample no. BC/TS-0. The palynological details 21 G. conspicua 1.2 are given below as the following: 22 G. gigas 1.2 Dominant: Scheuringipollenites Total 99.86 Sub-dominant: Indotriradites and Parasaccites Other taxa: Faunipollenites, Striatopodocarpites, Verticipollenites, Densipollenites, Weylandites cir- Cordaitales (Euryphyllum), Cycadales (Macrotae- cularis, Tiwariasporis simplex, Sahanites sp., niopteris) and Glossopteridales (Glossopteris and Distriatites bilateris Vertebraria) (table 3). The order Glossopteridales Trilete spore: Microfoveolatispora foveolata is highly diversified with 23 taxa and the genus Age marker taxa: Indotriradites, Faunipollen- Glossopteris with 22 species dominates the flora, ites varius, Rhizomaspora indica, Arcuatipollenites whereas the remaining genera have one species each ovatus and Callumispora sp. (table 4). Barring the genus Vertebraria, the other Palynodating: The assemblage is rich in having genera namely Paracalamites, Euryphyllum and zonate trilete spores. The occurrence of pollen taxa Macrotaeniopteris have rare occurrence (figure 6). Scheuringipollenites, Parasaccites and Striatopodo- Most of the Glossopteris species found in Raniganj carpites and spore taxon Callumispora in abundance Formation are either narrow mesh forms or along with other species, viz., Indotriradites, medium mesh forms and are relatively smaller Microfoveolatispora, Rhizomaspora and Densipol- in size. Glossopteris tenuifolia is the most dom- lenites in this palynoassemblage is similar to that inant species (14.45%) of this genus followed by known from the lower part of the Barakar For- G. nimishea (8.43%) and G. arberi (7.22%). The mation in the Damodar Basin, in having abun- group Glossopteridales is a dominantly preserved dance of Scheuringipollenites, Parasaccites and group. The assemblage of Jhingurdah Colliery is Faunipollenites along with the age marker species. mostly dominated by medium mesh forms of the Palynoassemblage-I can be correlated with Scheu- genus Glossopteris. In association with the leaf ringipollenites barakarensis Assemblage-I of Tiwari impressions, a large number of vertically pre- and Tripathi (1992). The recovered palynocomposi- served Vertebraria roots (65 specimens, accounting tion place these beds at the transition of Karhar- for 41.6%) are also found. The groups Lycopo- bari Formation and Lower Barakar Formation diales, Filicales, Sphenophyllales, Ginkgoales and and date them as late Early Permian (Artinskian). J. Earth Syst. Sci. (2017) 126: 25 Page 9 of 16 25

Figure 5. Relative percentages of various genera and Glossopteris species from Barakar Formation of Bina Colliery.

Figure 6. Relative percentage of various genera/groups collected from the Raniganj Formation of Jhingurdah Colliery.

In addition to these palynomorphs, an unusual and already established (Saxena et al. 2016a). dominance of spore tetrads is recorded in the Apart from the spores-pollen content, the pre- sample no. BC/TS-0, which are assignable to dominance of cuticle and amorphous matter, plant the dispersed microspore genera Indotriradites, tissues is also noted in this assemblage. Microbaculispora and Microfoveolatispora.Tetrads form a sizeable chunk, about 17% of the total paly- 5.2 Palynoassemblage-II noassemblage consisting of 15 spore/pollen genera. This is the first record of tetrads from any Artin- Sample nos. BC/PB-1, BC/PB-2 and BC/PB-3 skian strata in the world. Their significance and from Purewa Bottom coal seam role of being a possible indicator of the intense Dominant: Faunipollenites climatic regime (extreme cold) has been envisaged Sub-dominant: Scheuringipollenites 25 Page 10 of 16 J. Earth Syst. Sci. (2017) 126: 25

Table 5. Palynoassemblage zones derived from the Barakar and Raniganj formations, interpreted ages and important palynotaxa. Age inferred on the basis Palynoassemblage Assemblage zone of palyno- zones Composition identified Formation assemblages

Palyno- Dominance of Striatopodocarpites and Gondisporites Raniganj Late assemblage-IV subdominance of Faunipollenites along raniganjensis Permian with Scheuringipollenites and non-striate (Striatopodocarpites– bisaccate such as Alisporites, Faunipollenites) Falcisporites, etc. and stratigraphically age marker taxa are Crescentipollenites, Arcuatipollenites, Klausipollenites, Playfordiaspora, Striasulcites, Hamiapollenites and Striamonosaccites. Triletes are poor, represents Foveolatispora, Calamispora. Palyno- Dominance of Faunipollenites followed by Scheuringipollenites Raniganj Early assemblage -III Scheuringipollenites and lesser number barakarensis Permian of Striatopodocarpites Palyno- Dominance of Scheuringipollenites along Scheuringipollenites Barakar Early assemblage-II with fair presence of Laviegatospore. barakarensis Permian Other taxa rare in presence are: Faunipollenites, Striatopodocarpites, Rhizomaspora, Verticipollenites, Dicapipollenites, Parasaccities, Barakarites, Densipollenites and Foveolatispora Palyno- Dominance of Scheuringipollenites and Scheuringipollenites Barakar Early assemblage-I tetrad spores and sub-dominance of barakarensis Permian Parasaccites followed by Rhizomaspora, Striatopodocarpites, Verticipollenites, Faunipollenites Indotriradites, Arcuatipollenites with dark amorphous matter and woody flinters.

Other taxa: Densipollenites, Barakarites, 5.3 Palynoassemblage-III Parasaccites, Striatopodocarpites and Rhizomaspora. The recovery of spore pollen varies on an average Sample nos. JC/JB-1, JC/JB-2 and JC/JB-3 from from low to medium. Besides these palynomorphs, Jhingurdah Bottom Coal Seam woody shreds, plant tissues and organic matter In this coal seam, the sample nos. JC/JB-1 was were abundant. Qualitative analysis of the paly- found to be unproductive. noassemblage suggests an age younger than Lower Dominant: Scheuringipollenites Barakar in having characteristic palynomorphs Sub-dominant: Faunipollenites namely, Faunipollenites and Scheuringipollenites Other taxa: Striamonosaccites ovatus, Cres- in fair occurrence, followed by the presence of centipollenites, Hemiapollenites, Striatites, Vertici- Densipollenites pollen. The other stratigraphically pollenites, Corriasaccites, Barakarites, Dicappi- important pollen grains are Barakarites, Parasac- pollenites and Rhizomaspora cites, Striatopodocarpites and Rhizomaspora.The Trilete: Callumispora, Microfoveolatispora, triliete spores are scarce and are represented by Laevigatosporites Microfoveolatispora and Varietrilites. Age marker taxa: Scheuringipollenites baraka- Palynodating: This assemblage compares well rensis, Microbaculispora barakarensis, Horri- with the Faunipollenites varius Assemblage Zone ditriletes curvibaculosus and Barakarites indica. of Tiwari and Tripathi (1992) and dates Purewa Palynodating: Assemblage-III compares well Bottom Seam as Upper Barakar (Kungurian) in with the Scheuringipollenites barakarensis Assem- age having the dominance of Faunipollenites over blage Zone of Tiwari and Tripathi (1992) in the Scheuringipollenites. having the dominance of Scheuringipollenites and J. Earth Syst. Sci. (2017) 126: 25 Page 11 of 16 25

Figure 7. Palynomorphs recovered from the Barakar Formation of Bina Colliery, Singrauli coalfield. 1. Callumispora fungosa Balme (1973); 2. Microfoveolatispora sp.; 3, 4. Indotriradites korbaensis Tiwari (1964); 5. Indotriradites mamillatus Bhard- waj and Tiwari (1977); 6. Indotriradites sp.; 7. Indotriradites sparsus Tiwari (1964); 8. Parasaccites obscures Tiwari (1965); 9. Parasaccites korbaensis Bhardwaj and Tiwari (1964); 10. Densipollenites invisus Bharadwaj and Salujha (1964); 11. Densipollenites magnicorpus Tiwari and Rana (1981); 12. Striamonosaccites ovatus Bharadwaj (1962); 13. Distriamono- colpites ovalis Bharadwaj and Salujha (1969); 14. Playfordiaspora cancellosa; 15. Scheuringipollenites tentula Tiwari (1973); 16. Scheuringipollenites maximus Tiwari (1973); 17. Scheuringipollenites barakarensis Tiwari (1973); 18. varius Bharadwaj (1962); 19. Striatopodocarpites decorus Bharadwaj (1964). 25 Page 12 of 16 J. Earth Syst. Sci. (2017) 126: 25

Figure 8. Palynomorphs recovered from the Raniganj Formation of Jhingurdah Colliery, Singrauli coalfield. 1. Crescentipollenites fuscus Bharadwaj, Tiwari and Kar (1974); 2. Verticipollenites oblangus Bharadwaj (1962); 3. Rhizomaspora indica Tiwari (1965); 4. Rhizomaspora radiata Wilson (1962); 5. Distriatites bilateris Bharadwaj (1962); 6. Arcuatipollenites sp.; 7. Arcua- tipollenites ovatus Tiwari and Vijaya (1995); 8. Arcuatipollenites pellucidus Tiwari and Vijaya (1995); 9. Klausipollenites staplainii Jansonicus (1962); 10. Alisporites; 11. Alisporites australis de Jersey (1962); 12. Alisporites ovalis Kumar (1973); 13. Satsangisaccites nidpurensis Bharadwaj and Srivastava (1969); 14. Alisporites splendens (Leschick) Foster (1979); 15. Falcisporites mulhallensis Balme (1970); 16. Dicappipollenites crassus (Sinha) Tiwari and Vijaya (1995); 17. Crustae- sporites globosus Leschick (1956); 18. Weylandites minutes Bharadwaj and Srivastava (1969); 19. Laevigatosporites plicatus Kar (1968). J. Earth Syst. Sci. (2017) 126: 25 Page 13 of 16 25 sub-dominance of Faunipollenites along with other of the Glossopteris flora, i.e., Gangamopteris and age marker taxa. It is dated as late Early Permian Noeggerathiopsis, which are considered to be the (Artinskian) in age. Apart from spores-pollen, cuti- pioneer elements of the earliest Permian (Asselian) cle, amorphous matter and other plant tissues were time. also observed. In comparison to the prolific occurrence of the macrofloral remains in the Raniganj Formation, 5.4 Palynoassemblage-IV the presence of such remains is remarkably less in the Barakar Formation (table 3). However, the Sample nos. JC/JT-1 and JC/JT-2 from Jhingurdah leaves of the Barakar assemblage are quite big in Top Coal Seam size and medium to broad mesh forms, as com- Dominant: Striatopodocarpites pared to relatively smaller and narrow-medium Sub-dominant: Faunipollenites mesh leaves of the Raniganj Formation (Lele 1966; Other taxa: Scheuringipollenites, Alisporites, Saxena et al. 2016b). The richness, as well as the Falcisporites, Hamiapollenites, Striamonosaccites diversity, of the megaflora in Bina Colliery is and Distriatites. Triletes are poor, represented with comparatively very low, however, they have been Microfoveolatispora and Callumispora. observed quite high in the Barakar Formation of Age marker taxa: Crescentipollenites, Arcu- other coalfields namely, Talcher (Saxena et al. atipollenites, Klausipollenites, Playfordiaspora and 2014), Ib-River (Singh et al. 2006) and Korba Striasulcites. (Singh et al. 2011) of the Son–Mahanadi Basin. Palynodating: The Palynoassemblage IV is Further, none of the megafossils is preserved with very similar to the known palynoflora recovered cuticle, suggesting the complete oxidation of the from lower part of the Raniganj Formation in carbon content of the preserved fossils at least in Damodar Basin. Dominance of striate bisaccate these facies. On the contrary, the species diversity taxon Striatopodocarpites and sub-dominance of of the genus Glossopteris is very high in the Rani- Faunipollenites followed by Distriatites, Striamo- ganj floral assemblage as compared to its diversity nosaccites palynomorphs equates these beds in the Barakar assemblage. The Glossopteris plants with Palynoassemblage Zone-V, viz., Striatopodo- were seemingly deciduous as is evidenced by the carpites–Faunipollenites–Gondisporites Assemblage fact that a large number of its leaves are found pre- Zone of Tiwari and Tripathi (1992), and dates served singly/individually in different layers of sed- them as Late Permian (Lopingian) in age. FAD’s of iments of Jhingurdah Top seam. There are around Alisporites, Klausipollenites, Falcisporites, Arcu- 156 specimens of various taxa (table 3) in the atipollenites pellucidus and Playfordiaspora cancel- present Raniganj assemblage; most of them are well losa palynotaxa enhance the end Permian level, preserved with minor distortion, indicating that as these elements are the key species to mark the deposition site of the vegetal matter was not very transition of Permian into the Lower Triassic. far from the original growing site and deposition took place in a low energy environment. Moreover, in addition to the leaves and equisetalean axes pre- 6. Discussion served as impressions, the Raniganj flora of this coalfield comprises very well preserved in-situ Ver- The macro- and miofloral studies of the Lower tebraria roots, which are not reported from the Gondwana sequences belonging to the Talchir, Barakar and Talchir formations of this coalfield. Barakar and Raniganj formations of Singrauli Generally the climate during the deposition of coalfield, have been carried out to assess the Raniganj/Lower Kamthi Formation was warm and palynostratigraphic status and age of the studied humid with intermittent rainfall that resulted in starta; significant changes that had occurred in the development of dense forests of Glossopterid floral composition and in the associated climatic trees having medium-to-large sized leaves; and conditions responsible for the floristic variations small herbs and shrubs belonging to Pteridophytes through the Permian time in the Singrauli coalfield and other gymnosperms used to grow underneath basin. The macroflora recovered from the Talchir these plants (Chandra and Chandra 1988; Chandra (Early Permian) strata has revealed the occur- and Singh 1992; Goswami and Singh 2013). Such rence of Noeggerathiopsis–Gangamopteris complex, climatic conditions also favoured the production of which is completely devoid of the genus Glos- diverse fructifications as evidenced by the occur- sopteris. The Barakar Formation is represented by rence of these in the sediments along with the ster- diverse Gangamopteris–Glossopteris assemblage, ile leaves (Maheshwari 1965; Chandra and Singh whereas the flora of Raniganj Formation (Lopin- 1992). The occurrence of comparatively small- gian) is typically Glossopteris dominated flora that sized leaves of various species of Glossopteris and completely lack the genus Gangamopteris.The also the complete absence of fructifications in the Talchir flora consists of the earliest representatives Jhingurdah Top seam of this colliery advocates the 25 Page 14 of 16 J. Earth Syst. Sci. (2017) 126: 25 existence of warm and semi-arid conditions in Palynoassemblage-II, from the Purewa Bottom this area that possibly did not allow these plants seam, with Faunipollenites as the dominant taxon, to blossom and produce fructifications and also followed by Scheuringipollenites, Densipollenites, restricted their ability to bear normal leaves. Barakarites, Parasaccites, Striatopodocarpites and The macrofloral assemblages recovered from all Rhizomaspora seems to be quite similar to the Fau- the three formations are completely devoid of the nipollenites varius Palynoassemblage Zone-VI of plant groups Lycopodiales, Sphenophyllales, Fili- Tiwari and Tripathi (1992) and also to the Palyno- cales and Ginkgoales suggesting that the Moher composition III (B) of Tiwari and Tripathi (1987), Sub-basin area might not be adequately cool and which signifies the existence of moderately warm humid to facilitate the growth of these shade- climate with high humidity. Based on the palyno- loving, under-storied plants. composition of this assemblage, the beds can be It is very difficult to date the sediments precisely placed in late Early Permian (Kungurian) Upper on the mere basis of macroflora, however, the Barakar Formation. mioflora as well as the fauna always acted as a better Palynoassemblage-III from the Jhingurdah Bottom proxy for determining the precise dates. We have Seam has dominance of taxon Scheuringipollen- correlated and dated the studied sections with ites followed by Faunipollenites, Verticipollenites, the help of palynology. Four distinct palynoassem- Barakarites, Crescentipollenites, Corriasaccites, blages, namely I and II from Bina Colliery and Laevigatosporites and is comparable with the Scheu- III and IV from Jhingurdah Colliery have been ringipollenites barakarensis Assemblage Zone-V of recorded and interpreted to assess the biostrati- Tiwari and Tripathi (1992) and can be assigned graphic status of the studied strata (table 5). The Early Permian (Artinskian) age (Lower Barakar). entire strata including coal seams of Bina and However, the miospore assemblage recovered from Jhingurdah collieries have been broadly kept in the bore-core of Jhingurdah seam (top and bot- the Barakar and Raniganj formations, respectively tom) had a close affinity with the palynoassem- (Raja Rao 1983). However, the present palynolog- blage of Upper Barakar Formation (Bharadwaj ical investigations carried out on the known coal and Sinha 1969b). In a subsequent reappraisal, the seams in these collieries resulted in the confirma- mioflora of Jhingurdah seam was re-examined and tion of the sediments of Lower Barakar and Upper found to be closely comparable with the known Barakar in Bina Colliery and of Lower Barakar miofloras of Raniganj Formation (Tiwari and and Raniganj Formation in Jhingurdah Colliery. Srivatsava 1984). In the present study, the paly- The identified palynoassemblages have been noflora of Jhingurdah bottom seam shows affinities strictly correlated with the known and established with the palynoflora of Lower Barakar, whereas the palynoassemblage zones of Tiwari and Tripathi Palynoassemblage-IV from Jhingurdah Top seam (1987, 1992) based on the stratigraphical impor- is closely comparable with the mioflora of Raniganj tance of the age marker taxa, and their relative Formation. Such ambiguity in the palynodating occurrence along with other associated significant needs further thorough re-investigations to resolve species. this issue. The dominance of the taxon Scheuringipollenites Palynoassemblage-IV from the Jhingurdah Top followed by Indotriradites and Parasaccites in asso- Seam is characterised by the dominance of striate ciation with Faunipollenites and other taxa in bisaccate Striatopodocarpites and Faunipollenites Palynoassemblage-I from the Turra seam corre- in association with stratigraphically important taxa, lates these beds with Early Permian (Artinskian) namely Alisporites, Arcuatipollenites, Playfordias- Lower Barakar Formation. This palynoassemblage pora, Striasulcites, Klausipollenites and Densipolle- resemblesverywellwiththeScheuringipollenites nites. The Palynoassemblage-IV is compared with the barakarensis Palynoassemblage Zone-V of Tiwari Striatopodocarpites–Faunipollenites–Gondisporites and Tripathi (1992) and also with the Palynocom- Assemblage Zone of Tiwari and Tripathi (1992) position III (A) of Tiwari and Tripathi (1987), in Damodar Basin, thus assigning a Late Permian which indicates the prevalence of a cool climate (Lopingian) age. This assemblage is also compara- with high humidity during this period in Singrauli ble with the Assemblage-III of East Bokaro coal- coalfield. The palynoassemblage-I is also compa- field (Vijaya et al. 2012) and palynoassemblage-II rable with the Lower Barakar palynoflora of the of Sohagpur coalfield (Ram-Awatar et al. 2004). northern part of Singrauli coalfield (Vijaya et al. The presence of Alisporites, Klausipollenites, Fal- 2012), as well as other basins of India (Bharadwaj cisporites, Arcuatipollenites and Playfordiaspora and Srivastava 1973; Srivastava 1973; Tiwari palynotaxa along with other Late Permian paly- 1973; Bharadwaj et al. 1974; Tiwari et al. 1981; nomorphs in the Jhingurdah Top seam also place Srivastava and Jha 1992, 1996; Murthy et al. 2010; these beds at the transition of Late Permian and Vijaya et al. 2011). Lower Triassic. J. Earth Syst. Sci. (2017) 126: 25 Page 15 of 16 25

7. Conclusions Acknowledgements

• Earliest Permian (Asselian) Talchir Formation The authors are thankful to Prof. Sunil Bajpai, witnessed the lowest plant diversity in Moher Director, BSIP, Lucknow for the kind permission sub-basin of Singrauli coalfield (total five taxa to publish this work (BSIP/RDCC/16/2016-17/). representing three genera, viz., Gangamopteris, Sincere thanks are also due to Mr T K Nag, CMD Noeggerathiopsis and Samaropsis). The complete and Mr Niranjan Das, Director (Technical/Project and Planning), Singrauli coalfield, and also to the absence of the forms having a midrib, i.e., Glos- CGMs and GMs of Bina and Jhingurdah collieries sopteris in this formation may be attributed to for their help and permission to collect the plant extreme cold conditions with very low humid- fossils. We also appreciate the help from Mr V P ity in Talchir time (Tiwari and Tripathi 1987) Singh of BSIP during sample collection in the field. that probably restricted the development of such midrib possessing Glossopterids. • The moderately warm climate with high humid- References ity during the deposition of Barakar Formation (Tiwari and Tripathi 1987) has resulted in the Bharadwaj D C and Sinha V 1969a Some new miospores development of diversified macrofloras includ- from Lower Gondwana Coals, In: Sen Memorial Vol- ing forms with well-defined midrib representing ume (eds) Santapau H et al., Bot. Soc. Bengal, Calcutta, six genera (?Buriadia, Gangamopteris, Glos- pp. 7–16. sopteris,cf.Noeggerathiopsis, Samaropsis and Bharadwaj D C and Sinha V 1969b Sporological succession and age of Jhingurdah Seam, Singrauli coalfield, M.P., Cordaicarpus)and17taxa. India; Palaeobotanist 17 275–287. • The flora further evolved and diversified in the Bharadwaj D C and Srivastava S C 1973 Subsurface Raniganj Formation as evidenced by the occur- palynological succession in Korba coalfield, M.P., India; rence of five genera with 26 species in the Jhin- Palaeobotanist 20 137–151. Bharadwaj D C, Navale G K B and Prakash Anand 1974 gurdah Top seam of Jhingurdah Colliery. The Palynostratigraphy and petrology of Lower Gondwana genus Glossopteris with 22 species tops the diver- coals in Pench–Kanhan coalfield, Satpura Gondwana sity scale, however, the relatively smaller size of Basin, M.P., India; Geophytol. 4 7–24. leaves of various species of Glossopteris and also Chandra S and Chandra A 1988 Vegetational changes and the complete absence of the fructifications in this their climatic implications in coal-bearing Gondwana; Palaeobotanist 36 74–86. seam advocates the preponderance of warm and Chandra S and Singh K J 1992 The genus Glossopteris from semi-arid conditions in this area that possibly the Late Permian beds of Handapa, Orissa, India; Rev. did not allow these plants to grow normally and Palaeobot. Palynol. 75 183–218. produce fructifications. Goswami S and Singh K J 2013 Floral biodiversity and • geology of the Talcher Basin, Orissa, India during the Identification of Scheuringipollenites barakaren- Permian–Triassic interval; Geol. J. 48 39–56. sis and Faunipollenites varius Palynoassemblage Lele K M 1966 Studies in the Talchir flora of India-4; Quest Zones in the Turra and Purewa Bottom seams of for the early traces and subsequent development of the Bina Colliery, respectively, have led to the assign- Glossopteris flora in the Talchir Stage, Symposium on floristics and stratigraphy of Gondwanaland, Birbal Sahni ment of an Early Permian (Artinskian–Lower Institute of Palaeobotany, Lucknow, pp. 85–97. Barakar) age to Turra seam and late Early Per- Lele K M, Swarup P and Singh J N 1968 Occurrence of plant mian (Kungurian–Upper Barakar) age to Purewa fossils in the Lower Gondwana sucession of Singhrauli Bottom coal seam. coalfield, U.P.; J. Palaeontol. Soc. India 11 8–17. • Maheshwari H 1965 Studies in the Glossopteris flora of India- The occurrence of Scheuringipollenites 23; On two fructifications from the Raniganj stage of the barakarensis Palynoassemblage Zone in the Raniganj coalfield, Bengal; Palaeobotanist 13 144–147. Jhingurdah Bottom coal seam of Jhingurdah Mishra B K and Singh B D 1990 The lower Permian coal Colliery is unbelievable as this seam otherwise seams from Singrauli coalfield (M.P.), India: Petrochemi- cal nature, rank, age and sedimentation; Int. J. Coal Geol. belongs to Raniganj Formation, however, Jhingur- 14 309–342. dah Top seam certainly is of Late Permian Mukhopadhyay G, Mukhopadhyay S K, Roychowdhury M (Lopingian) age because of the occurrence of and Paraui P K 2010 Stratigraphic correlations between Striatopodocarpites–Faunipollenites–Gondisporites different Gondwana basins of India; J. Geol. Soc. India Palynoassemblage Zone in it. 76 251–266. Murthy S, Chakraborty B and Roy M D 2010 Palynodat- • The FAD’s of Alisporites, Klausipollenites, ing of subsurface sediments, Raniganj coalfield, Damodar Falcisporites, Arcuatipollenites and Playfordia- Basin, West Bengal; J. Earth Syst. Sci. 119(5) 701–710. spora palynotaxa observed in the Jhingurdah Pareek H S 1969 Petrological study of coals from Singrauli coalfield, M.P.; Rec.Geol.Sur.India97 87–90. Top seam enhance the end Permian level and Pareek H S 1970 Petrology of coal, burnt coal and parva also place these beds at the transition of Late lava from Singrauli coalfield, M.P. and U.P; J. Geol. Soc. Permian and Lower Triassic. India 11 333–347. 25 Page 16 of 16 J. Earth Syst. Sci. (2017) 126: 25

Raja Rao C S 1983 Coalfields of India, Vol. III; Coal Sinha V 1972 Sporae dispersae from Jhingurdah Seam, resources of Madhya Pradesh, Jammu and Kashmir; Bull. Singrauli coalfield – (M.P.); Palaeobotanist 19 175–201. Geol. Surv. India, Series A 45 75–80. Srivastava S C 1973 Palynostratigraphy of the Giridih Ram-Awatar, Mukhopadhyay A and Adhikari S 2004 Paly- coalfield; Geophytol. 3 184–194. nostratigraphy of sub surface Lower Gondwana, Pali Srivastava S C and Jha N 1992 Palynostratigraphy of sediments, Sohagpur coalfield, Madhya Pradesh, India; Permian sediments in area, Godavari Graben, Palaeobotanist 53 51–59. , In: Proceedings of Birbal Sahni Birth Saxena A, Singh K J, Murthy S, Chandra S and Goswami Centenary Palaeobotanical Conference (eds) Venkatachala S 2016a Spore tetrads, possible indicators of intense V S, Jain K P and Awasti N; Geophytol. 22 103–110. climatic regimes: Case study from an early Permian Srivastava S C and Jha N 1996 Palynology of sub-surface stratum of Singrauli coalfield, Son–Mahanadi Basin, Permian sediments in Kothagudem area, Godavari India; Geol. Mag. 153 426–437. Graben, Andhra Pradesh; Geophytol. 25 131–136. Saxena A, Singh K J, Shabbar H. and Prakash A 2016b Tiwari R S 1969 Sporological succession in Purew Seam, Sin- Macrofloral assemblage from the Early Permian Barakar grauli coalfield, M.P; J. Sen Memorial Volume, Botanical Formation of Singrauli coalfield, Son–Mahanadi Basin, Society of Bengal, Calcutta, pp. 93–100. India; Palaeobotanist 65 139–150. Tiwari R S 1971 Sporological succession in Kota and Turra Saxena A, Singh K J and Goswami S 2014 Advent seams, Singrauli coalfield (M.P.), India; Palaeobotanist and decline of the genus Glossopteris Brongniart in 18(3) 264–269. the Talcher coalfield, Mahanadi Basin, , India; Tiwari R S 1973 Palynological succession in the Barakar type Palaeobotanist 63 157–168. area; Geophytol. 3 166–183. Singh B D and Mishra B K 1991 The variable nature of Tiwari R S and Srivatsava S C 1984 Palynological dating the coal types, rank and formation of some of the Lower of Jhingurdah Seam, Singrauli coalfield: A reappraisal; Gondwana coals in Son valley, Central India; Minetech. Palaeobotanist 31 263–269. 12 43–59. Tiwari R S and Tripathi A 1987 Palynological zones and Singh K J and Saxena A 2015 End Permian (Lopin- their climatic inference in the coal bearing Gondwana of gian) floral diversity in Singrauli coalfield: Evidences peninsular India; Palaeobotanist 36 87–101. from Jhingurdah Colliery, Son–Mahanadi Basin, India; Tiwari R S and Tripathi A 1992 Marker assemblage zones J. Paleontol. Soc. India 60 97–112. of spore and pollen species through Gondwana Palaeo- Singh K J, Goswami S and Chandra S 2006 The genus Glos- zoic and Mesozoic sequence in India; Palaeobotanist 40 sopteris from Lower Gondwana formations of Ib-River 194–236. coalfield, Orissa, India; J.Palaeontol.Soc.India51(2) Tiwari R S, Srivastava S C, Tripathi A and Singh V 81–107. 1981 Palynostratigraphy of Lower Gondwana sediments Singh K J, Goswami S and Srivastava G 2011 Palaeodiver- in Jharia coalfield, ; Geophytol. 11 220–237. sity in the genus Glossopteris from the Lower Gondwana Trivedi B S 1950 Megaspores from Lower Gondwana of rocks of the Korba coalfield, State, India; Singrauli coalfield District ; Curr. Sci. 19 126. J. Palaeontol. Soc. India 56 39–59. Vijaya Srikanta M, Chakraborty B and Roy J S 2011 Singh K J, Saxena A and Goswami S 2016 In-situ occur- Palynological dating of subsurface coal bearing horizon rence of Vertebraria roots in the Raniganj Formation of in East Bokaro coalfield, Damodar Basin, ; Singrauli coalfield and its palaeoecological significance; Palaeontogr 288 41–66. Curr. Sci. 110(3) 299–301. Vijaya Tripathi A, Roy A and Mitra S 2012 Palynostrati- Sinha V 1969 Some “Acritarchs” and other microfossils from graphy and age correlation of subsurface strata within the Barakar stage of Lower Gondwana, India; Palaeobotanist sub-basins in Singrauli Gondwana Basin, India; J. Earth 17 326–331. Syst. Sci. 121(4) 1071–1092.

MS received 10 May 2016; revised 8 September 2016; accepted 23 October 2016

Corresponding editor: Pratul K Saraswati