Gondwana Sediments Research Articles

Significance of the regional lineament tectonics in the evolution of the Pranhita–Godavari sedimentary basin interpreted from the satellite data

Remote sensing studies of the Pranhita–Godavari (PG) valley helped to identify five major sets of lineaments trending NW–SE, WNW–ESE, NE–SW, E–W and NNE–SSW to N–S. Based on their spatial extent, they are classified as mega, intermediate and short types. The mega lineaments, trending NW–SE and engraved in the Dharwar and Bastar Craton, seem to be responsible for configuring the Proterozoic basin margins. The PG mega lineament, which follows the Pranhita and Godavari rivers, controlled the deposition of Proterozoic and Gondwana sediments throughout the period of development of the basin. Two NW–SE trending mega lineaments, one about 60 km southwest of the present day Pakhal exposures and the other a little to the northeast of Albaka ridge, appear to define the initial graben margin of the PG valley. Periodic reactivation of NW–SE, WNW–ESE, N–S and E–W trending lineaments appear to have developed fault-bound basins where the Proterozoic Group of rocks belonging to Pakhal, Albaka, Penganga and Sullavai were deposited and preserved. Albaka, however, remained a positive area during Gondwana deposition. The NE–SW trending lineament, uncommon in the main basin, restricted the extension of the Proterozoic basin in the southeast and could be the surface manifestation of the convergence of the Eastern Ghat Belt against the Peninsular cratons. The onset of Gondwana sedimentation seems to have taken place on block-faulted Proterozoic basins that evolved due to repeated sagging along the northwestern set and PG lineament. Pre-Gondwana fracturing of the craton witnessed extension of the NW–SE trending lineament into the Eastern Ghat and this, in association with reactivation of pre-existing NE–SW, WNW–ESE and E–W fractures of the Eastern Ghat sequence, might have been responsible for the evolution of a series of interconnected Gondwana Basins on the older Eastern Ghat.

Bouguer anomaly of the Godavari basin, India and magnetic characteristics of rocks along its coastal margin and continental shelf

The Bouguer anomaly map of the Godavari basin has delineated several transverse and median ridges that have divided this basin into several sub-basins. Modelling of a gravity profile in the central part of the basin suggests 5.0 km of Gondwana sediments and high density rocks along the shoulders which may represent upthrusted lower crustal rocks related to the Eastern Ghats orogeny. The total intensity magnetic map of the coastal part of the Godavari basin shows a well-defined magnetic anomaly of approximately 200 nT along the coast which coincides with the Kaza basement ridge. The modelling of this magnetic anomaly indicates 2–2.5 km of sediments over the Kaza ridge and 5.5–6 km thick sediments in the depressions towards the west of this ridge which are constrained from the basement configuration based on seismic sections in the surrounding region. The Kaza ridge, with a susceptibility of 10 −4 SI units, appears to be composed of basic rocks which may be part of the exposed Eastern Ghats towards the west. This magnetic map also shows several high amplitude short wavelength anomalies which are caused by sub-surface basic rocks. These basic rocks are related to the Rajahmundry trap, equivalent to the Deccan traps of late Cretaceous age, and are exposed nearby by. Modelling of the magnetic anomaly across the continental shelf, off the coast of the Godavari basin, suggests an almost 45° inclined contact away from shore at a depth of 2.5 km and having a thickness of 3.5 km. However, this magnetic anomaly could be matched only with a remanent magnetization with declination 310° and inclination −67° which corresponds to the direction of magnetization reported for the Rajmahal traps.

Delineation of shallow structure and the Gondwana graben in the Mahanadi delta, India, using forward modeling of first arrival seismic data

We derived 2-D shallow velocity structure, in order to delineate low-velocity Gondwana sediments underlain by high-velocity volcanics in the north, to determine sediment thickness in the south and to map the basement configuration along the N–S trending Konark–Mukundpur profile, Mahanadi delta, India. We applied the ray-based 2-D forward modeling technique to the first arrival seismic refraction traveltime data. The shallow velocity structure has been derived to a depth of 4 km. The main features of the model are the Konark depression (0–15 km), the Bhubaneswar ridge (15–50 km), the Cuttack depression or the Gondwana graben (50–100 km) and the Chandikhol ridge (100–115 km) along the profile. The overall structures represent alternate graben and horst features. In the south, the Konark depression is composed of three sedimentary formations with velocities of 1.75, 2.4 and 4.0 km/s and attains a maximum depth of 2.9 km at 9 km profile distance. To the north, a low velocity (4.0 km/s) layer of basinal shape, believed to be the Gondwana sediments, is delineated in the Gondwana graben using the ‘skip’ phenomenon of travel time data. This layer with a maximum thickness of 1.75 km near Cuttack lies between a thin (∼100–300 m) cover of high-velocity volcanic (5.25 km/s) and underlying basement (6.0 km/s) rocks. The model indicates upwarping of basement on either side of the Gondwana graben.

Evolution in Basin Fill Style During the Mesozoic Gondwana Continental Break-up in the Godavari Triple Junction, SE India

Consistent changes are observed in the Mesozoic sedimentary lithofacies and palaeocurrents during the transition from the continental Gondwana (NW-SE trending Chintalpudi Graben - CG) to the coastal Gondwana (NE-SW trending Krishna Godavari Coastal Basin - KGCB) in the Godavari Triple Junction (GTJ). The Mesozoic continental Gondwana sediments include the Kamthi (early Triassic), Kota (Jurassic) and Gangapur (early Cretaceous) Formations. Coastal Gondwana succession comprising the Raghavapuram (early Cretaceous) and the Tirupati (Middle to late Cretaceous) Formations transversely superimpose the continental Gondwana. The Continental Gondwana is mainly cross-stratified sandstone and fossiliferous ( Glossopteris and Ptilophyllum flora) clay assemblage of alluvial environment. Palaeocurrent is towards NW in the Kamthi Formation, WNW in the Kota Formation and centripetal in the Gangapur Formation. The Raghavapuram Formation (KGCB) comprises of grey/carbonaceous clay-sandstone association of SE flowing delta plain distributories with inter-distributory swamps and fossiliferous white clay (a mix of Ptilophyllum flora and invertebrate fauna) of prodelta / shallow marine environment. The succeeding sandstone- conglomerate facies of the Tirupati Formation (Middle to late Cretaceous) with SE palaeocurrent indicates delta progradation whereas the infratrappean clay-limestone beds (mainly invertebrate fauna of Maastrichtian age) point to delta abandonment, prior to the K/T boundary volcanism. Tectono-sedimentary model presented in this communication incorporates that the change from the continental Gondwana to coastal Gondwana had occurred in four stages. During stage-I (late Carboniferous to early Jurassic) the sediments were deposited by a north-westerly flowing alluvial system whose distal source was located in southeast beyond the east coast of India. Stage -II (Middle to late Jurassic) is marked by westerly shift in palaeocurrents attributed to an obstruction caused by an upliftment of the Mailaram high parallel to the NE-SW Eastern Ghat trend. Stage-III (early Cretaceous) is heralded by the onset of deltaic sedimentation in SE due to separation of landmass that supplied detritus to the CG until the end of the Jurassic. During stage-IV, the delta progradation is accentuated by the basement uplift (Eastern Ghat Mobile Belt). It is suggested that the change over from continental Gondwana to coastal Gondwana had occurred over a time span of about 70 my between late Jurassic to Cretaceous and controlled by phase-wise upliftment of the basement as a corollary to the Gondwana continental break-up.

Imaging of low-velocity Gondwana sediments in the Mahanadi delta of India using traveltime inversion of first arrival seismic data

The Gondwana sediment, exposed in the western part of the Mahanadi delta of India, is expected to be present below the high-velocity volcanic formation in the alluvium-covered Cuttack depression. Both near-vertical reflection profiling and first-arrival seismic refraction work have limitations to image the low-velocity sedimentary strata and underlying formations due to low penetration of seismic energy and nongeneration of critically refracted rays from the top of the low-velocity zone, respectively. However, when the thickness of the overlying high-velocity layer is very small and/or the velocity gradient is high, the velocity inversion is indicated by delays of the first arrivals. We inverted the traveltimes of first arrivals and few later arrivals into two dimensions, utilizing a priori information about the thickness of the overlying high-velocity volcanic rock from a nearby well log and estimated the thickness of the low-velocity (4.00 km/s) Gondwana sediments sandwiched between a thin (∼200 m) cover of high-velocity (5.20 km/s) volcanic rock and underlying basement (∼5.90–6.15 km/s). The Gondwana sediment, having a basinal shape, attains a maximum thickness of ∼1.50 km at the middle of the depression near Cuttack. The basement depth is 50–250 m on either side of the depression. The seismically derived shallow structure correctly explains the Bouguer anomaly observed along the seismic line. This serves as a check to validate the derived model.

Lageniculate megaspores from the Lower Gondwana sediments of Madhya Pradesh, India

Lageniculate megaspores from the Lower Gondwana sediments of Madhya Pradesh, India

Alluvial Fan-Lacustrine Sedimentation and its Tectonic Implications in the Cretaceous Athgarh Gondwana Basin, Orissa, India

Abstract The Athgarh Formation is the northernmost extension of the east coast Upper Gondwana sediments of Peninsular India. The formation of the present area is a clastic succession of 700 m thick and was built against an upland scarp along the north and northwestern boundary of the basin marked by an E-W-ENE-WSW boundary fault. A regular variation in the dominant facies types and association of lithofacies from the basin margin to the basin centre reveals deposition of the succession in an alluvial fan environment with the development of proximal, mid and distal fan subenvironments with the distal part of the fan merging into a lake. Several fans coalesced along the basin margin, forming a southeasterly sloping, broad and extensive alluvial plain terminating to a lake in the centre of the basin. Aggradation of fans along the subsiding margin of the basin resulted in the Athgarh succession showing remarkable lateral facies change in the down-dip direction. The proximal fan conglomerates pass into the sandstone-dominated mid-fan deposits, which, in turn, grade into the cyclic sequences of sandstone-mudstone of the distal fan origin. Further downslope, thick sequence of lacustrine shales occur. The faulted boundary condition of the basin and a thick pile of lacustrine sediments at the centre of the basin suggest that tectonism both in the source area and depositional site has played an important role throughout the deposition of the Athgarh succession of the present area. The vertical succession fines upward with the coarse proximal deposits at the base and fine distal deposits at the top, suggesting deposition of the succession during progressive reduction of the source area relief after a single rapid uplift related to a boundary fault movement. The NW-SE trending fault defining the Son-Mahanadi basin of Lower Gondwana sediments are shear zones of great antiquity and these were rejuvenated under neo-tensional stress during Lower Gondwana sedimentation. The E-W-ENE-WSW trending fault of the Athgarh basin, on the other hand, define tensional rupture of much younger date. In the Early Cretaceous period, there was a reversal of palaeoslope in the Athgarh basin (southward slope) with respect to the Son-Mahanadi basin (northward slope). During the phase drifting of the Indian continent and with the evolution of Indian Ocean in the Early Cretaceous period, the tectonic events in the plate interior was manifested by formation of new grabens like the Athgarh graben.

Role of Storm in Ramgarh and West Bokaro Coalfields and Its Implication in Adjacent Peninsular Gondwana Coalfields, India

The Permian Gondwana sediments in the Damodar-Koel Valley, Rajmahal and Deoghar basins were deposited on a northwest palaeoslope in broad valleys within uplands (e.g. Aravalli-Vindhyan, Chattisgarh, Chotanagpur and Santhal Parganas upland). The main winds during Permian Period were mostly the westerly winds coming from the northwest low pressure belt in the Tethys, which found no barrier between the Vindhyan and Santhal Parganas uplands and then changing its direction, moving towards east. Frequent storm activity also took place from the northwest Tethyan low pressure belt and followed the same path of wind. Possibly there was a barrier in the form of a dense rain forest or elevated land at the place of East Bokaro coalfield and its adjoining southern part, which acted as a deterrent and minimized the effect of storm towards further east of the Damodar Valley. Intense tropical hurricanes for the generation of storm generated bedforms, cannot be ruled out, which probably, in some cases, causes marine inundation/flooding deep into the landmass and also mass (?) uprooting of trees.

Tectono-sedimentary evolution of the Gondwanan Satpura Basin of central India: evidence of pre-Trap doming, rifting and pal˦oslope reversal

The Mesozoic Gondwanan Satpura Basin of central India, comprising an approximately 1300 m thick sequence of the Pachmarhi, Denwa and Bagra Formations, was subjected to at least three major tectonic events. These events are manifested by tectonic dislocation, marginal uplifts, basin subsidence and deformation, as well as by stratigraphical disposition, lithofacies assemblage, and palaeoslope and pal˦ocurrent patterns. The first tectonic event is manifested by the onset of Early Triassic Pachmarhi sedimentation, which is marked in the basal part by a sudden increase of conglomeratic, pebbly, gritty to coarsegrained cross-bedded sandstone. This contrasts with the underlying fine elastics of the Late Permian Bijori Formation. The stratigraphical relationship and lithofacies, together with pal˦ocurrent and petrographic data, reflect tectonic uplift in the source area to the southeast of the Satpura Basin during or prior to the deposition of Pachmarhi Formation. The pebbly coarse sandy facies of the Pachmarhi Formation represents a braided river assemblage, overlain by a meandering river facies of the Denwa Formation, with river systems flowing dominantly from southeast to northwest. The progressive change in lithofacies and grain size upward from Pachmarhi to Denwa implies that the source area became peneplained and that the basin stabilised. During the prolonged gap of non-deposition, following the Mid-Triassic break in sedimentation after deposition of the Denwa Formation, a second tectonic event resulted in the widespread faulting and uplift of Permo-Triassic Gondwana sediments and basement rocks, respectively, to the south and north of the Narmada-Son Lineament Zone of Peninsular India. A third tectonic event is manifested by Late Jurassic-Early Cretaceous Bagra conglomerate and sandstone-shale facies in the northern part of the Satpura Basin. This formation, which unconformably overlies the Precambrian, and Permian and Triassic Gondwana formations or abuts against faulted contacts, represents proximal and distal facies of an alluvial fan deposit in a rifted (pull-apart?) basin with uplifted highlands to the north. This tectonism, representing the termination of continental Gondwana sedimentation, preceded the widespread eruption of the Deccan Traps (65 Ma) after the break-up of India from Antarctica. As a consequence, a northward sloping, peninsular craton was tilted southward and small rift basins developed along peripheral parts to the north, west and along the east coast of Peninsular India. To the north of the study area, the doming before the Deccan volcanism and tectonic movement along the Narmada-Son Lineament caused uplift of the Palaeoproterozoic Mahakoshal/Bijawar terrane. This uplift was accompanied by a reversal of palaeoslope. Consequently, north to south pal˦currents followed the deposition of the Pachmarhi and Denwa Formations, as borne out by the alluvial fan-braided complex of the Bagra Formation.

Discovery of Gondwana plant fossils and palynomorphs of Late Asselian (Early Permian) age in the Karakoram Block

We report the discovery of Early Permian (late Asselian, ∼280–275 Ma) plant fossils and associated palynomorphs from a marine sedimentary sequence of the eastern Karakoram plate, in northern India. These specimens show affinities with those found in marine Lower Gondwana sediments of the Indian subcontinent. This supports the contention that during the Early Permian Period, the Karakoram plate was Peri‐Gondwanan. It is suggested to have had an intermediate position between the Indian plate and the Qiangtang–Lhasa microcontinents, at a latitude of about 35° south.

The problem of velocity inversion in refraction seismics: some observations from modelling results

The applicability of seismic refraction profiling for the detection of velocity inversion, which is also known as a low-velocity layer (LVL), is investigated with the aid of synthetic seismogram computations for a range of models. Our computational models focus on the inherent ambiguities in the interpretation of first-arrival time delays or ‘skips’ in terms of LVL model parameters. The present modelling results reveal that neither the measure nor even the existence of a shadow zone and/or a time shift (skip) in first arrivals is necessarily indicative of an LVL. Besides attenuation effects, the cap-layer velocity gradient is a critical parameter, determining the termination point of the cap-layer diving wave and thus the time skip. We suggest that shallow LVLs can be delineated more reliably by traveltime and amplitude modelling of coherent phases reflected from their top and bottom boundaries, often clearly observed in the pre- and near-critical ranges in seismogram sections of refraction profiling experiments with a close receiver spacing. We demonstrate the applicability of this approach for a field data set of a refraction profile in the West Bengal Basin, India. The inferred LVL corresponds to the Gondwana sediments underlying the higher-velocity layer of the Rajmahal Traps. This interpretation is consistent with the data from a nearby well in the region.

Grain-size frequency distribution in ancient depositional environment ? A case study from Lower Gondwana Sediments, Pranhita Godavari Basin, Andhra Pradesh Majumdar P. & Ganapathi S., Journal of the Geological Society of India, 1998, 52/2 (219?228)

Grain-size frequency distribution in ancient depositional environment ? A case study from Lower Gondwana Sediments, Pranhita Godavari Basin, Andhra Pradesh Majumdar P. & Ganapathi S., Journal of the Geological Society of India, 1998, 52/2 (219?228)

Recumbent flame structures in the Lower Gondwana rocks of the Jharia Basin, India — a plausible origin

A set of recumbent flame structures was found within a stacked channel complex belonging to the Raniganj Formation (Upper Permian) of the Lower Gondwana sediments of the Jharia Basin, India. The characteristics, particularly the relation with the erosional base of the overlying channel, the nature of the host layer and the geometry of the flame structures suggest that the horizontal gradient in pore fluid pressure, developed within the concealed layer, in response to the differential loading due to partial removal of the overburden during erosional incision, was responsible for triggering the static liquefaction of the sediments and the density-driven deformation of the sand–mud interface took place. Rounded excrescence of sand bulged downward into the underlying mud, which in turn was projected upward in the form of sharp flames following the trajectory of the pore fluid. Gradual bending of the flow trajectory towards the horizontal direction due to the presence of the overlying impermeable mud layer led to the development of the recumbent geometry of the flame structures.

Sequence stratigraphic analysis of pre-Tertiary succession in Ganga Basin : Singh A.K. & Singh J.N., Journal — Geological Society of India, 1997, 49/6 (629–646)

The paper defines the Pre-Tertiary stratigraphy of the Ganga Basin which is concealed beneath the thick cover of Cenozoic sediments. The sub-surface structural configuration is characterised by development of four major depressions, separated by transverse uplifts. Ganga Basin represents two main stages of geological evolution: a pre-collisional (Pre-Tertiary) stage consisting mainly of Proterozoic and Gondwana sediments, and a post-collisional (Tertiary) stage representing the Siwalik molasse. The Pre-Tertiary succession is classified into four mega sequences; three of these representing Precambrian sediments, comprising of Aravalli, Bijawar, Delhi and Vindhyan systems and one megasequence corresponding to Gondwana system in the Pumea Depression.

Sedimentary environmental model for Lower Gondwana sediments around Bellampalli, Pranhita-Godavari Basin, Andhra Pradesh : Majumdar P., Jain A. & Ganapathi S., Indian Journal of Petroleum Geology, 1996, 5/1 (97–119)

Sedimentary environmental model for Lower Gondwana sediments around Bellampalli, Pranhita-Godavari Basin, Andhra Pradesh : Majumdar P., Jain A. & Ganapathi S., Indian Journal of Petroleum Geology, 1996, 5/1 (97–119)

Structure of the crystalline basement in the West Bengal basin, India, as determined from DSS studies

SUMMARY Deep seismic sounding data were acquired in the West Bengal basin, India, along two profiles: (i) Bishnupur-Palashi-Kandi, along a line about 227 km long in the northsouth direction and (ii) Taki-Arambagh, along a line about 120 km long in the east-west direction. Seismic refraction and wide-angle reflection data were recorded by continuous profiling using two 60-channel digital seismic units (DFS-V) with an 80 m geophone group interval and 4 ms sampling rate. These data were interpreted in order to delineate the basement configuration. The 2-D models of the seismic data both indicate a five-layer velocity structure above the Archaean crystalline basement (5.9-6.2 km s-I). A low-velocity layer (4.0 km s-') is inferred immediately above the basement in the shelf region of the basin corresponding to the Gondwana sediments (Upper Carboniferous to Lower Triassic) below the Rajmahal Traps (Upper Jurassic to Lower Cretaceous) of 4.6 to 4.8 km s-' velocity, which is also confirmed from the nearby well data. The results along the Taki-Arambagh profile and the drilling results at the Jaguli (J-1) well are used to investigate whether Gondwana sediments and the Rajmahal Traps exist in the deep part of the Bengal basin. An additional layer of velocity 5.2-5.3 km s- ', delineated in the Palashi-Kandi profile overlying the basement, may correspond to the Singhbhum group of rocks of the Proterozoic. A structural contour map of the basement prepared from the present results indicates a south-easterly dip of the basement in general. The depth of the basement on the stable shelf of the basin gently increases to about 8 km and dips steeply, plunging to a maximum depth of 14 km in the deep basin. No structural high that can be related to the 'Calcutta gravity high' is found in the basement around the Hooghly River.

An unusual pycnoxylic wood from a new Upper Gondwana locality in Tamil Nadu, India

Though fossil woods assignable to the form-genus Dadoxylon or Araucarioxylon are rather common in the Upper Gondwana sediments of the Indian Peninsula, a species of Araucarioxylon collected from a hitherto unreported locality in Tamil Nadu, India, is shown to possess unusual characteristics reminiscent of ephedroid anatomy. The wood is compared with the palaeotaxon Cretaceous clusteredpits previously reported from Williams Point beds, Livingston Island, Antarctic Peninsula, to which it shows remarkable similarities. Comparisons are also made with other Araucarioxylon species mainly to emphasise the unusual features of the new wood which is designated A. mosurense Jeyasingh and Kumarasamy, sp. nov. The fact that the wood comes from a locality from where no other megafossils have been reported so far, adds colour to the report while giving clues to the age of the new fossiliferous site.

Upper Crustal Structure in the Torni-Purnad Region, Central India Using Magnetotelluric Studies.

Magnetotelluric studies were conducted over a 100 km long NS profile in the Satpura range and Tapti basin. Data were collected at 18 stations in this region with an interstation spacing of 3-10 km. The geoelectric substructure was obtained using a two dimensional modelling technique and has indicated the presence of Deccan traps and Gondwana sediments overlying a rather complex granitic basement. Two distinct layers of Deccan basalts were delineated with a total thickness varying from 2000 m in the central part to about 300-1000 m on either sides of this NS trending profile. The thickness of the Gondwana sediments below the traps was observed to vary rather strongly in the range, 300-2000 m. Two vertical conductive zones were delineated corresponding to the Khandwa lineament and the Burhanpur tear but the sensitivity studies indicated a large degree of nonuniquness associated regarding the shape and vertical extent of these conductors. An interesting finding of these studies is the presence of a prism shaped body in the central part of the survey profile in the Satpura horst region at depths between 3.5 and 14 km with a resistivity of 20 ohm-m. The body had a lateral extent of 8 km at the top and 40 km at the bottom in the NS direction. This observation is discussed along with the other geophysical results in the Satpura and Tapti regions.

Geomagnetic depth sounding over the Singhbhum and the surrounding regions of eastern India

Magnetovariational studies have been carried out in Singhbhum and surrounding regions during 1987 and 1989. Three deep-seated linear conductors have been identified. One of them is located to the north of Ranchi, Bokaro and Purulia extending in E-W direction coinciding with high heat flow region and Gondwana sediments. The trend of anomaly at Ranchi and Purulia at longer periods suggests a conductivity anomaly due to the mafic and ultramafic intrusions, considered to be responsible for the uplift of Chhotanagpur plateau. The second conductor is associated with the basin margin fault that separates the Singhbhum craton and Chhotanagpur plateau from the West Bengal basin. This conductive zone appears to extend further south and join the high heat flow region of Attri-Tarabalo. This conductor could be isolated only after eliminating the coast effect from the observed induction vectors. The third conductive zone follows the trend of Mahanadi valley located south of the Sukinda thrust. Conductive anomaly associated with the Sukinda and Singhbhum thrust zones could not be resolved due to the interference from neighbouring conductive structures. These two thrusts may not be very deep-seated structures. The Singhbhum granite batholith is found to be highly resistive and seems to extend to greater depths.

Palynological dating of Lower Gondwana sediments in Sattupalli area, Chintalpudi sub-basin, Andhra Pradesh, India

The palynological study of bore-cores GSS-1, GS-1, 2, 3 and 4 from Sattupalli area, Chintalpudi sub-basin, reveals the presence of Talchir, Barakar and Raniganj palynoassemblages. The coal seams and associated sediments present between 74.40 to 152.70 m in bore-core GSS-1, at 99.50 m in GS-1, at 371 m in bore-core GS-2, at 46-74 m in GS-3 and 181-230 m in bore-core GS-4 contain Raniganj palynofloral alongwith early appearance of Early Triassic taxa, viz., Lunatisporites, Klausipollenites, Lundbladispora, Densoisporites, Vitreisporites and Chordasporites. Talchir and Barakar palynofloras have been marked at 402 and 356.51 m in bore-core GSS-1 respectively.