Satpura Basin Research Articles

Satpuraphyllum furcatum—a new genus and species of Peltaspermales foliage from the mid-Permian Barakar Formation of India

Satpuraphyllum furcatum gen. et sp. nov. is introduced to accommodate once- to twice-forked leaves with slender entire-margined segments containing a midrib that gives off very acute, freely dichotomizing, secondary veins. The leaves are amphistomatic, bearing incompletely monocyclic to amphicyclic stomata and diverse trichomes, papillae, and sparse multicellular low domal glands. These collective characters favour assignment to Peltaspermales and this is supported by co-preservation, in the same beds, of leaves with shield-shaped bracts bearing marginal seed scars. Satpuraphyllum furcatum is documented from the upper Barakar Formation (Kungurian) of central India and is the oldest known peltasperm from the core regions of Gondwana. Its presence in the Satpura Basin at that time signifies an early penetration of Peltaspermales into the Southern Hemisphere, possibly during the Artinskian–Kungurian Warming Event (initiating ca 287 Ma). Deepa Agnihotri [ deepa_agnihotri@bsip.res.in ] Birbal Sahni Institute of Palaeosciences, 53 University Road, Lucknow-226007, India. AK Srivastava [ srivasatava019@gmail.com ] 5/595, Vikas Nagar, Lucknow, India. Stephen McLoughlin* [ steve.mcloughlin@nrm.se ] Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, Stockholm, 10405, Sweden.

Paleomagnetism of mafic dykes in South Rewa Basin, India: Constraints to extension of Deccan volcanism

The magma source for mafic dykes from South Rewa Basin (SRB) in central India is invariably linked to Rajmahal volcanism (117 Ma) for Damodar, Raniganj-Jharia, and Bengal basin (Permian - Quaternary) to the east, and Deccan volcanism (66 Ma) for Satpura Basin to the west of SRB. However, the magmatic events linked to the SRB are not explicit. To ascertain the dyke association with these volcanic events, we performed a comprehensive paleomagnetic study on the exposed dykes and basalts from Shahdol region in SRB. Rock magnetism indicate that magnetite or titano-magnetite is the main remanence carrier mineral in these dykes. The measured directions produce a mean declination (Dm) of 338° and mean inclination (Im) of - 35° (α95= 8.4°, k = 25.3, N = 13), is close to Deccan normal directions. The calculated Pole position (λp) is at 42.02°N, and (Lp) is at 289.33°E, suggesting that the studied dykes are emplaced simultaneously along with Deccan Traps (36.96°N/78.70°W) and not of Rajmahal Traps (11.37°N/297.58°E). These dykes can be the result of multiple Deccan magma intrusions along the Narmada-Tapti lineament and intra-basinal faults in the SRB of central India.

Evolution of the Permo‐Triassic Satpura Gondwana Basin, Madhya Pradesh, India: Insights from geochemical provenance and palaeoclimate of the siliciclastic sediments

Geochemical study in the siliciclastic sediments of a basin provides an understanding of palaeoclimate, provenance and subsequently, it can be used to reconstruct the palaeo‐tectonics and evolution of the basin. Sedimentation in the Gondwana basins, worldwide, generally provides a record of climatic fluctuations and evidences of the Permo‐Triassic mass extinction. In spite of its global importance, our knowledge about the nature of sedimentation, basin development and conceptual regional tectonic model in the Satpura Basin, one of the Gondwana basins of India is limited. Major and trace element concentrations of the mudstones from the Denwa Formation along with the existing geochemical data of other formations are studied here for establishing a comprehensive idea about the palaeoclimate, tectonic settings, provenance and basin evolution. The composition of the sediments in the lowermost Talchir Formation revealed cold and dry climatic conditions at the sources, whereas the sources of the sediments for the overlying formations have experienced warm, humid and semiarid climates. The contributions of the mafic rock‐derived sediments are relatively higher in the Talchir, Barakar and Motur formations compared to the overlying formations. Approximately 60% of the sediments in the overlying Bijori, Pachmarhi and Denwa formations were derived from the felsic volcanic rocks and granites of the Sausar Mobile Belt and Betul‐Chindwara Mobile Belt (BCMB) with minor inputs from mafic volcanic rocks of the BCMB. Furthermore, the sediments of the Talchir Formation were derived from the BCMB when they became tectonically active, whereas the sediments in the younger formations have been derived from a passive tectonic setting.

Atmospheric CO2 estimates based on Gondwanan (Indian) pedogenic carbonates reveal positive linkage with Mesozoic temperature variations

CO 2 is an important greenhouse gas that is known to drive global climatic changes. Multiple studies tracking p CO 2 changes throughout the Phanerozoic have highlighted the linkage between CO 2 levels and the corresponding icehouse-greenhouse conditions. However, deviations from the above relationship due to inconsistencies in p CO 2 estimation, as well as large time-steps in existing geochemical models and gaps in proxy data suggest that the paleo- p CO 2 record is not always well-constrained. Here, we attempt to reconstruct atmospheric CO 2 concentration for parts of the late Early and Middle Triassic and Early Cretaceous from several carbonate-forming paleosols of the Indian Gondwana. We measured the carbon isotopic composition of pedogenic carbonates (δ 13 C carb ) and organic matter occluded within soil carbonates (δ 13 C org ) from Pachmarhi, Denwa, and Bagra Formation of the Satpura Basin ( n = 60) to estimate CO 2 using a pedogenic carbonate-based paleo-barometer. The late Early Triassic (Olenekian) shows low CO 2 concentrations (562 ± 426 ppmV), which is followed by an increase (822 ± 523 ppmV) in the Middle Triassic (Anisian). The Early Cretaceous is found to have the highest average concentration (1517 ± 594 ppmV). Our p CO 2 estimates are well correlated with the existing proxy record and geochemical models and suggest fluctuations in CO 2 levels that are consistent with temperature variations previously estimated for the periods. • Atmospheric CO 2 is reconstructed from Gondwana paleosols for parts of the Mesozoic. • Our pCO 2 data correlate well with geochemical models and other proxies. • Atmospheric CO 2 estimates also show excellent correlation with temperature. • Early parts of Triassic show large variations in atmospheric CO 2 concentration. • A new dynamic soil-respired CO 2 -proxy is formulated from modern soil data.

The osteology of Shringasaurus indicus, an archosauromorph from the Middle Triassic Denwa Formation, Satpura Gondwana Basin, Central India

ABSTRACT Archosauromorpha originated in the middle–late Permian and started to diversify in both non-marine and marine ecosystems dominating the world by the Triassic. The evolution of this group is poorly documented because the fossil record is limited. A detailed osteological description of Shringasaurus indicus, a non-archosaurian archosauromorph, from the Middle Triassic Satpura Basin, Central India, is provided here. The collection includes cranial bones, namely the nasal, frontals with and without horns, postfrontal, parietal, maxilla, premaxilla, quadrate, vomer, dentary, and braincase. The collection also comprises postcranial bones such as cervical, dorsal, sacral and caudal vertebrae, and girdle and limb bones. The phylogenetic study incorporates the character states from cranial as well as postcranial elements of Shringasaurus indicus. Furthermore, Malerisaurus robinsonae, another non-archosaurian archosauromorph from India, has been included in the phylogenetic analysis. The analysis reveals that both Shringasaurus indicus and Malerisaurus robinsonae are azendohsaurid allokotosaurs and Shringasaurus indicus is the sister taxon to both the species of Azendohsaurus. The detailed description of Shringasaurus indicus elucidates that the animal had a pair of supraorbital horns, was a large herbivore, and has an incongruous mixture of basal archosauromorph and dinosaurian-like character-states. Hence, the present study helps to fill the gap, to a large extent, in understanding the nature of the morphological diversity of basal archosauromorphs after the Permian–Triassic mass extinction. SUPPLEMENTAL DATA–Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

Slumping as a record of regional tectonics and palaeoslope changes in the Satpura Basin, central India

Abstract Soft-sediment deformation structures play an important role in interpreting regional tectonics and basin evolution during slumping events. The Satpura Basin is interpreted as pull-apart with a monoclinal northerly palaeoslope throughout its evolution. The basin formed as a result of sinistral strike-slip faulting, induced by the ENE–WSW-trending Son-Narmada South fault in the north and the Tapti North fault in the south. We have analysed the slump folds within the basalmost Talchir Formation and related these to regional tectonics and palaeoslope changes in the Satpura Basin. The glaciofluvial strata of the Talchir Formation, exposed in the southern part of the Satpura Basin, record intricacies of folds created during slumping. Several fold styles can be distinguished, within alternations of competent sandstone and incompetent shale layers, some of which indicate buckling. Upright folds, resulting from pure shear, underwent rotation of their axial planes and fold axes during simple shear-dominated progressive deformation when the slump moved downslope. The soft-sediment deformation structures that we have studied show refolding patterns that closely resemble comparable folds known from lithified rocks. These layers with refolded structures are overlain by unde-formed sediments, which proves that they are the product of a single ongoing slumping process, rather than of successive deformation events. Our analysis of their fold axes and axial planes, together with fold vergences and thrust directions within the slumps, suggests a mean slumping direction towards the southwest. Analyses of slump folds and their relationship with regional tectonics have allowed us to reinterpret basin evolution history. The southwesterly trending palaeoslope of the basin suggest that the slope of the basin was not uniform throughout its evolution. At the opening, the oblique slip fault, which trended NE–SW, generated due to movement along the ENE–WSW basin bounding faults, was more active and triggered slumping event within the Talchir deposits in the basin. With progressive overlapping of the basin-bounding faults, the Satpura Basin gradually tilted towards the north.

Effects of thermal maturity on biomarker distributions in Gondwana coals from the Satpura and Damodar Valley Basins, India

Organic geochemistry of Gondwana coals, especially the distribution of molecular fossils or biomarkers, is not well constrained, throughout the world. In this study, we have, therefore, evaluated biomarker signatures along with bulk organic matter and petrographic characteristics in coal samples collected from two Gondwana Basins in India – Satpura Basin (Kanhan coalfield) and Damodar Valley Basin (Jharia coalfield). From both coalfields, the samples were collected from the Lower Permian Barakar Formation, which is one of the major coal bearing strata in India. A significant variation in thermal maturity levels in the samples is indicated by Rock-Eval pyrolysis and petrographic analysis–with the Kanhan samples generally belonging to immature to early-mature stage, while the Jharia samples display characteristics of overmature coals. This variation in the thermal maturity strongly affects the biomarker distributions. Especially, the terpenoids, hopanes and steranes were considerably degraded due to thermal maturation and were below detection limit in the overmature samples. Presence of aliphatic diterpanes, ent-16α(H)-kaurane, 16α(H)-phyllocladane as well as aromatic diterpanes, retene, methylretenes, tetrahydroretene, simonellite and bisnorsimonellite in low maturity samples indicate terrestrial input, possibly, from the primitive conifers. However, the aliphatic and aromatic diterpanes were below detection limit in overmature samples making it difficult to infer their source. Distributions of polycyclic aromatic hydrocarbons (PAHs) are also controlled by thermal maturity levels, as evident from difference in PAH ratios in the low and high maturity samples.

Late Permian palynoassemblage from Borehole No. WG-22 near Sekapur, Wardha District, Maharashtra, India

The present paper deals with the palynological investigation of the Lower Gondwana sequence intersected in Borehole No. WG–22, drilled near Sekapur Village, in Wardha District, Maharashtra. The study divulges the incidence in significant proportion and with consistency of striate bisaccate palynomorphs, viz. Striatopodocarpites and Faunipollenites and non–striate genus Scheuringipollenites. The associated genera recorded include, Weylandites, Tiwariasporis, Densipollenites, Verticipollenites and Klausipollenites, though with meagre distribution. This palynoassemblage has been dated as Late Permian and affiliate closely with the palynofloral assemblages known from the basal part Raniganj Formation of East and West Bokaro coalfields, Damodar Basin, Makardhokada area of Nagpur District and vast areas of Godavari Valley. The study indicates that almost similar vegetational pattern existed in the Nagpur, Wardha–Godavari and Damodar basins however, there existed regional variations in the generic composition of the vegetation in Satpura Basin as suggested by their palynofloral contents. The mega– and microfloral studies of the Wardha Basin with particular reference to Sekapur area suggests prevalence of warm and temperate climate in this region.

Stratigraphy of the Upper Gondwana Formations around Sohagpur, Western Part of the Satpura Gondwana Basin, Central India

Abstract: The present work provides a detailed lithological map of the western part of the Satpura basin around Sohagpur and reports the presence of new archosauromorph fossil bones from that region. The study area is dominated by the Bagra Formation along with a narrow patch of the underlying upper part of the Denwa Formation. The lower Denwa and the underlying Pachmarhi formations are absent here. The presence of the Pachmarhi Formation, as a tongue shaped area, as mapped by Crookshank (1936) is discarded in this study on the basis of lithology and petrographic analyses, instead the presence of the Bagra Formation is suggested in this area. A comparison of the lithologies and the vertebrate faunas of the upper Gondwana formations between eastern and western part of the basin has been carried out for the first time. The comparison indicates that the Denwa Formation present in the western sector represents only the topmost part of the formation while the complete succession of Denwa is preserved in the eastern sector. The Bagra Formation in the western sector documents the presence of sheet-like sandstone bodies unlike the eastern part. The vertebrate fauna of the eastern part is dominated by temnospondyl amphibians while that of the western part is dominated by archosauromorph. The vertebrate fossils of upper part of Denwa Formation, found from similar lithologies in west and east though, have differences in the amount of transportation before their burial.

Petrofacies, provenance, and paleocurrent analysis of Pachmarhi sandstone (Early Triassic), Satpura basin, Central India

The Satpura Gondwana basin hosts a ∼5 km thick siliciclastic succession that unconformably overlies the Precambrian basement. The Gondwana sequence in this basin starts from Early Permian (Talchir Formation) to Lower Cretaceous (Jabalpur Formation). The aim of this study is to (1) identify the source rock (provenance) for Early Triassic Pachmarhi sediments in the Satpura Gondwana succession and (2) to understand the relative role of tectonics and climate in determining the sandstone composition. These sandstones are medium to coarse-grained, moderately to moderately well sorted, subangular to subrounded, of moderate sphericity, and composed of several varieties of quartz, feldspar, rock fragments, and micas. Petrographically, the Pachmarhi sandstones are mostly quartzarenite and subarkose. The petrofacies in Qt–F–L and Qm–F–Lt triangular diagrams show that the bulk of the Pachmarhi was derived from continental (cratonic) source, especially from craton interior. Petrofacies, together with paleocurrent data, suggest that Pachmarhi Formation was deposited by a network of braided river system, which flowed dominantly from southeast to northwest. The study suggests that the sediments were mostly derived from Precambrian granites, gneiss, and metasedimentary basement rocks straddling the southern margin of the basin. Paleocurrent data also corroborates this contention.

Petrography and Provenance of Early Triassic Pachmarhi Formation Sandstones, Satpura Gondwana Basin, Madhya Pradesh, Central India

The Pachmarhi, Denwa and Bagra Formations comprise of terrigenous sediments predominantly constitute the Mesozoic Gondwana sequence in Satpura basin of Madhya Pradesh, central India. The Pachmarhi Formation sandstones were studied with a view to understand the nature of the Satpura basin in relation to provenance and tectonic setting. Twenty representative samples of sandstone from Pachmarhi were examined for detrital mineralogy, petrofacies and tectonic implications. These sandstones are medium to coarse grained, moderately to moderately well sorted, subangular to subrounded and of moderate sphericity and composed of several varieties of quartz, feldspar, rock fragments, mica and a suite of heavy minerals. Petrographically, the Pachmarhi sandstones are quartzarenite and subarkose. The petrofacies studies reflect derivation of the sediments from continental block provenance and stable cratonic to fault-bounded basement uplift tectonic setting. The study suggests that the Precambrian granitoids occurring in the southern margin of the Satpura basin contributed sediments during Pachmarhi sedimentation.

Palynomorphs and Oribatid Mites—From the Denwa Formation, Satpura Basin, Madhya Pradesh, India

Palynological investigation of the Denwa Formation exposed along Denwa river succession at Saptadara picnic point near village Jhirpa, Satpura Basin, Madhya Pradesh, has revealed the presence of spore-pollen, fungal remains and Oribatid mites. Here, the mites are on record for the first time. Presence of fungal remains strongly depicts the prevalence of a very humid climate with high temperature and rainfall in the region. Poor occurrence of spore-pollen restricts the age determination of the studied section; hence, its age assessment is relative. Thus, an over-view of spore-pollen along with dinocysts and insects reported earlier from the subsurface strata comprising Denwa Formation, from other two localities in the nearby area of village Anhoni, is dealt herein, and that had inferred an age—range from Carnian to Rhaetic for the palynoflora and fauna.

Peltasperms in the Permian of India and their bearing on Gondwanaland reconstruction and climatic interpretation

We report on the first find of peltasperms in the Permian of Gondwana. Well-preserved leaf compressions and reproductive structures of these plants came from the Lower Permian Barakar Formation of Satpura Basin, central India, where they co-occur with diverse glossopterids. The Indian peltasperm record is evidence of floristic exchanges between Laurasia and Gondwana in the Early Permian involving a dominant group of North American–European arboreal vegetation of the time. The phytogeographic differentiation, leaf micromorphology and stratigraphic occurrence of Permian peltasperms suggest a thermophilic group appearing in central India during the transition from humid peat forming to seasonally dry redbed environments. Therefore peltasperms are unlikely invaders to high-latitude cool-temperate zone postulated for Early Permian Australindia. Instead their Satpura occurrence assigns the Indian subcontinent in the equatorial zone of mixed Laurasian/Gondwanan floristic assemblages.

Extension of Godavari Gondwana sediments underneath Trap covered region of Satpura basin as evidenced from seismic studies in Deccan Syneclise, India

We present a shallow P-wave velocity structure of the eastern part of Deccan Syneclise, central India, from the refraction and wide-angle reflection data recorded along two ∼100 km long seismic refraction profiles in east–west (E–W) and north–south (N–S) directions using travel time inversion method. In addition to the P-wave velocity model, we have derived S-wave velocity model and estimated Vp/Vs and Poisson’s ratios along the east–west profile. Travel time analysis and inversion of the data revealed three layers above the basement. The first layer with a P-wave velocity of 1.4–1.5 km s −1 represents alluvium and the thickness of this layer is varying between 100–400 m in the E–W and 30–100 m in the N–S profile. The Deccan Trap thickness is observed to be varying between 850 and 1250 m constitutes the second layer. P-wave velocity of the Deccan Traps is 4.8–5.2 km s −1. Amplitude decay and travel time skips in the first arrival refraction data in some of the record sections indicate the presence of a velocity inversion i.e. low velocity zone (LVZ) beneath the Traps. Wide-angle reflection phases from top and bottom of the LVZ (top of basement) together with basement refraction phase are identified and modeled to derive LVZ thickness. The LVZ has been interpreted to be the Gondwana sediments sandwiched between Deccan Traps and basement. These sediments are about 200–450 m thick with a P-wave velocity of 3.6 km s −1. The basement lies at about 1.60 km depth near Khandala in the west and Rajola in the north shows an upward trend towards south–east. The P-wave velocity of the basement is about 6.0–6.2 km s −1. The inferred subtrappean sediments could be the possible extension of Gondwana sediments of the Godavari graben towards the Satpura basin.

Geochemistry of Permo-Triassic mudstone of the Satpura Gondwana basin, central India: Clues for provenance

Major and trace element data of the Permo-Triassic mudstones from the intracratonic Satpura Gondwana basin, central India have been used to investigate provenance. The Satpura succession (~ 5 km thick) unconformably overlies the Precambrian basement. Sediment dispersal pattern suggests that the Precambrian rocks straddling the southern margin of the Satpura basin were the most probable source for the sediments. The lowermost unit of the Satpura succession comprises glacio-marine and glacio-fluvial deposits. The rest of the succession largely represents a variety of fluvial depositional systems with some records of fluvio-deltaic and fluvio-lacustrine sedimentation under a climatic spectrum of temperate, humid to warm, semi-arid. The present study is confined to the lower six formations namely Talchir, Barakar, Motur, Bijori, Pachmarhi and Denwa, arranged in that order from bottom to top. The oldest rocks of this sequence, the Talchir Formation, are enriched in mobile elements such as Na, Ca and Mg, depleted in alumina and have high ICV (0.93–1.29) and lower CIA values (61.82–74.89) compared to those of the younger mudstones. K 2O/Al 2O 3 ratios of the Talchir mudstones (0.24–0.28) are higher than the younger mudstones in this sequence. These results suggest that the Talchir mudstones were weathered less intensely and are thus more immature than the younger mudstones. This is consistent with the prevailing cold climate and relatively higher rate of basin subsidence. In contrast, the majority of the mudstones from the younger formations are depleted in mobile elements, have relatively low ICV (0.18–0.87) and K 2O/Al 2O 3 values (0.07–0.26), higher CIA values (76.99–92.86), and appear compositionally more mature reflecting moderate to high intensity source rock weathering. Among them, the Barakar mudstones likely have been more intensely weathered than mudstones from any of the other formations. The trace element compositions and ratios are consistent with most mudstones being derived from a felsic source with some mudstones being derived from a more mafic source. For example, La/Sc (0.805 and 0.114), La/Th (6.245, 5.072, 7.418, 6.245, and 5.072) and Eu/Eu* (1.431, 0.868, and 0.805) of some mudstones indicate mafic source. Bivariate plot of Th/Sc and Zr/Sc indicates considerable enrichment of zircon that suggests recycling from meta-sedimentary rocks. Prominent negative Eu anomaly, high LREE/HREE, and flat HREE pattern reflect sediment derivation from predominantly felsic rocks of the old upper continental crust. SiO 2/Al 2O 3 versus K 2O/Na 2O plot for the mudstones suggests that they formed in a passive margin. Also, total REE content of most of the mudstones is conformable with passive margin tectonic setting and craton interior type of provenance. Plotting in La–Th–Sc, Th–Sc–Zr/10 and La/Sc versus Ti/Zr diagrams largely indicates continental margin settings for majority of the mudstones but fails to differentiate between active and passive continental margins.

Biodiversity and palaeoclimatic interpretation of Early Cretaceous flora of Jabalpur Formation, Satpura Basin, India

The Jabalpur Formation of Jabalpur series, named after Jabalpur city in Central India, is exposed along the Narbada River, in Satpura Basin. The series is divided into the lower Chaugan and the upper Jabalpur stages. The Jabalpur beds occur between Mahadevas and Lametas at Mahadeva Hills, exhibit highest Gondwanan strata, and embody diversified flora. These beds also extend laterally to Bairam and Belkher areas in western part of central India. The highest diversity of the floral assemblage is recorded in the central portion of the basin (Sehora and Hasnapur) whereas the lowest diversity is recorded in Morand River, Parsapani and Tilaksindoor areas. The diversity in floral assemblage indicates the dominance of conifers and pteridophytes along with cycadophytes and certain pteridosperms. The palynofloral assemblage from this formation contains pollen and spores of bryophytic, pteridophytic and gymnospermic groups. The palaeovegetational diversity, biostratigraphic correlation and phytogeographic distribution of the Jabalpur flora are discussed in comparison with various coeval floras of Indian peninsula along with contemporaneous deposits of the other Gondwanan regions. The palaeogeographic analysis suggests that the flora was thriving as mixed vegetation during Early Cretaceous under seasonally hot and dry or alternating with wet and dry condition.

Pattern of sedimentation during the Late Paleozoic, Gondwanaland glaciation: An example from the Talchir Formation, Satpura Gondwana basin, central India

The Talchir Formation of Permian age is the lowermost lithostratigraphic unit of the Indian Gondwana successions preserving a record of the Late Paleozoic glaciation that affected the whole Gondwanaland. The formation unconformably overlies the Precambrian basement in all the Gondwana basins of India, and marks initiation of sedimentation after a long hiatus since the Proterozoic. The Talchir Formation of the Satpura Gondwana basin of central India shows features diagnostic of deposition under glacial regime such as the presence of diamictites, boulder pavements, bedding plane striation, faceted/striated gravels, bullet-shaped clasts, dropstone, cryoturbation, etc. The Talchir strata of the Satpura basin, in addition to tidal signatures, contain marine bivalve and trace fossils. A proglacial marine environment is thus inferred for their deposition. The dominant lithologies are conglomerate, pebbly sandstone, sandstone and shale with little limestone, which can be classified into the following major facies: • matrix-supported conglomerate, • clast-supported conglomerate, • cross-stratified, channel form pebbly sandstone, • hummocky, swaley or low-angle cross-stratified pebbly and non-pebbly sandstone, • turbidite/tempestite sheet sandstone, • massive to fissile, green to black claystone with carbonate layers and nodules. The conglomerates are interpreted as deposits of a spectrum of sub-aqueous sediment gravity flows including debris flow, hyperconcentrated/concentrated density flow and grain flow. The crossstratified pebbly sandstone bodies, on the other hand, represent braidplain delta deposits of glacial outwash origin. Hummocky, swaley, low-angle cross-stratified sediment bodies were deposited by storm-generated combined flows in a shoreface setting. In contrast, the sheet sandstone bodies are products of turbidity currents and storm-induced density currents in an inner shelf setting below fair weather wave base. The claystone facies is interpreted as a product of suspension fallout from hypopycnal sediment plumes in the outer shelf domain below storm wave base. All the lithofacies described above occur repetitively in the succession. Three facies-associations have been recognized in the Talchir Formation, representing ice-contact fandelta, outwash braidplain delta and a virtually ice-free, non-deltaic open marine realm. The different marine facies of the Talchir Formation define a number of shallowing-upward packages, which are arranged in the succession with a retrogradational trend to result in an overall fining- and deepening-upward succession. The overlying coal-bearing Barakar Formation has been interpreted to have formed in a tide-wave influenced

Pull-apart origin of the Satpura Gondwana basin, central India

The Gondwana basins of peninsular India are traditionally considered as extensional-rift basins due to the overwhelming evidence of fault-controlled synsedimentary subsidence. These basins indeed originated under a bulk extensional tectonic regime, due to failure of the attenuated crust along pre-existing zones of weakness inherited from Precambrian structural fabrics. However, disposition of the basins and their structural architecture indicate that the kinematics of all the basins cannot be extensional. To maintain kinematic compatibility with other basins as well as the bulk lateral extension, some basins ought to be of strike-slip origin. The disposition, shape and structural architecture of the Satpura basin, central India suggest that the basin could be a pull-apart basin that developed above a releasing jog of a left-stepping strike-slip fault system defined by the Son-Narmada south fault and Tapti north fault in consequence to sinistral displacement along WSW-ENE. Development of a sedimentary basin under the above-mentioned kinematic condition was simulated in model experiments with sandpack. The shape, relative size, stratigraphic and structural architecture of the experimental basin tally with that of the Satpura basin. The experimental results also provide insights into the tectono-sedimentary evolution of the Satpura basin in particular and pull-apart basins in general.

05/00944 Petrographic characteristics and depositional conditions of Permian coals of Pench, Kanhan, and Tawa Valley Coalfields of Satpura Basin, Madhya Pradesh, India

05/00944 Petrographic characteristics and depositional conditions of Permian coals of Pench, Kanhan, and Tawa Valley Coalfields of Satpura Basin, Madhya Pradesh, India

05/00545 Petrographic characteristics and depositional conditions of Permian coals of Pench, Kanhan, and Tawa Valley Coalfields of Satpura Basin, Madhya Pradesh, India

05/00545 Petrographic characteristics and depositional conditions of Permian coals of Pench, Kanhan, and Tawa Valley Coalfields of Satpura Basin, Madhya Pradesh, India