Paleomires of Eocene lignites of Bhavnagar,Saurashtra basin (Gujarat), western India: Petrographic implications

The Tertiary basins of Gujarat have always been a potential target for their hydrocarbon resources. The lignite resources of the region have also been an important field of research. The present paper presents the results of the petrological study carried out on the lignites of the Saurashtra basin. For this purpose samples were collected from lower and upper lignite seams from the Surkha lignite mine of Bhavnagar, Saurashtra. These samples were subjected to detailed petrographic analysis (both maceral and microlithotype). The study reveals that these lignites are dominantly composed of huminite group macerals while liptinite and inertinite group macerals occur in subordinate amounts. These lignites have attained a thermal maturity up to 0.28-0.30 percent vitrinite reflectance (VRr) which classifies them as ‘low rank C’ coals. Moreover, Bhavnagar lower lignite seam shows relatively less gelification as compared to the upper seam which suffered relatively more biochemical degradation. These lignites are characterized by high gelification index (GI) and low tissue preservation index (TPI).With the help of petrography based facies models an attempt has been made to reconstruct the environment of the paleomire of these lignites.     

受红河断裂控制的晚第三纪走滑松弛盆地——以漠沙盆地为例

中新世以来,受青藏高原造山隆起产生的侧向推挤,滇西及邻区发生向南东的哪构造逸脱,红河断裂发生右行走滑运动,在漠沙、逸萨等断裂弯曲地段由于应力松弛发生下陷,形成小型走滑松弛盆地,其特征有别于拉分盆地.本文以漠沙盆地为例,通过砂岩薄片粒度分析及砂岩碎屑组分定量分析,综合野外及室内地质研究,对此类盆地的岩石学特征、沉积环境、物源和构造特征等进行了详细的研究,并对其形成机制进行了初步的探讨.     

Sedimentological characteristics and facies of the evaporite-bearing Kirmir Formation (Neogene), Beypazari Basin, central Anatolia, Turkey

A thick sedimentary sequence comprising fluvial, lacustrine and volcano-sedimentary rocks is present in the Neogene Beypazari Basin, central Anatolia. These units display considerable lateral facies variation and interfinger with alkaline volcanic rocks along the north-eastern margin of the basin. The uppermost Miocene Kirmir Formation contains numerous evaporite horizons. The evaporite sequence is up to 250 m thick and may be divided into four lithofacies. In ascending stratigraphical order these are: (1) gypsiferous claystone facies, (2) thenardite-glauberite facies, (3) laminar gypsum facies and (4) crystalline gypsum facies. These facies interfinger with one another laterally along a section from the margins to central parts of the basin. The lithological and sedimentological features of the Kirmir Formation indicate fluvial, saline playa mudflat, hypersaline ephemeral playa lake and very shallow subaqueous playa lake depositional environments, which probably were influenced by alternating semi-arid and evaporative conditions.     

西藏札达盆地上新统一早更新统河湖相地层多重地层划分与对比

根据札达盆地河湖相地层实测剖面中的接触关系、沉积旋回、沉积体系、岩相、岩性、古生物特征和ESR、古地磁测年结果,笔者对札达盆地上新统一早更新统河湖相地层进行了重新划分和时代确定。结合该套河湖相沉积的岩石地层、生物地层、年代地层、磁性地层、层序地层和地质构造事件,对札达盆地上新统一早更新统河湖相地层进行了多重地层的划分与对比。将札达盆地河湖相地层划分为3个组、4个沉积相、7个沉积亚相、11个岩性段。由新到老划分为：早更新统香孜组（Qp^1-1X）、上新统古格组（N22g）和上新统托林组（N2^1t）。     

Zeolites in Tertiary coal from the Çayirhan mine, Beypazari, Turkey

The study focuses on the mineralogy of the upper coal seam accumulated at the top of the Çoraklar Formation (Miocene), Beypazari, Turkey. This coal seam is laterally extensive and averages 3.0 m thick, varying from 1.0 to 4.9 m. Analcime and clinoptiolite comprise up to 80% of the mineral matter (which also includes feldspars, quartz and pyrite and traces of dolomite, clay minerals and apatite) in the coal from the Cayirhan mine. Zeolites were formed when sodium-rich solutions altered aluminosilicate epiclastic material derived from contemporaneous volcanic activity. The allocthonous organic matter accumulated as a result of detrital plant and epiclastic material from an adjacent fresh-water environment being washed into a saline lake in sufficient quantities to form peat with a high mineral matter content (29.7% mean mineral matter content in raw coal). Subsequent syngenetic alteration of the volcanic glass incorporated into the peat resulted in zeolite formation. Alteration of sodium-rich epiclastic material by sodium-rich solutions resulted in the formation of analcime, whilst alteration of calcium-rich epiclastic material by sodium-rich solutions resulted in the formation of clinoptilolite.     

Distribution and geochemistry of selected trace elements in the lignites of Cambay basin,Gujarat, western India

In the present investigation all the working lignite seams of Cambay basin of Gujarat have been studied to see the distribution and geochemistry of selected major/minor elements like Fe, Ca, Na, K, Mg, and Mn and trace elements like Cu, Co, Cr, Cd, Ni, Pb and Zn. The vertical variation of these elements along the seam profiles has been studied to see the pattern of distribution of these elements and also to know the horizons of their enrichment and the probable cause. Further, these elements have been correlated among themselves and also with organic and inorganic matter of lignite. The correlation study indicates that in Tadkeshwar upper seam Fe has its affinity with huminite while Mg and Na have their affinity with liptinite and in Tadkeshwar lower seam Na has an affinity with liptinite. In Vastan upper seam Mn and Cu are associated with inertinite and Na with huminite while in Vastan lower seam Cu relates to huminite and Cd to liptinite and huminite. In Rajpardi seam Ca and Co are associated with huminite. The study provides information on the mode of occurrence of elements of less studied lignites of western India.     

Depositional environments of Late Eocene lignite-bearing strata, east-central Texas

Late Eocene lignites in the Brazos River Valley area occur in parasequence-scale cycles containing mostly marine sediments. Lignite is present at the base of the marine interval and forms the base of the cycle in a majority of cases. Less frequently, lignite is underlain by a thin interval of nonmarine deposits that form the base of the cycle. In both situations, the lignite is part of a thin transgressive interval. Cycles are separated by an exposure surface, usually marked by plant rooting and/or development of a paleosol in the top of the underlying sediments. Peat accumulated on top of these exposure surfaces and lignite is preserved where marine flooding allowed ocean waters to cover the peat deposits with fine grained sediments, producing high-ash lignite horizons of great lateral extent but variable thickness and quality. This strandplain model of lignite occurrence provides a better understanding of Late Eocene lignites in Texas than the deltaic or fluvial-deltaic models previously used. The strandplain model of lignite occurrence is appropriate for most of the Yegua-Jackson lignites (Middle-Late Eocene) of Texas and should be considered when evaluating depositional conditions of Paleogene lignites in the northern Gulf Coast region. A re-evaluation of Late Eocene stratigraphy of the Brazos Valley area accompanies the documentation of depositional environments.     

Sedimentology,stratigraphy and palynological occurrences of the late Cretaceous Erlian Formation,Erlian Basin,Inner Mongolia,People's Republic of China

The Erlian Basin is one of the non-marine Cretaceous basins of north-east China that developed during the late Mesozoic continental extension in eastern Asia. This basin experienced two major tectonic events: (i) a syn-rift stage that was dominated by a fluvial–lacustrine depositional environment and (ii) a post-rift stage that was dominated by a fluvial environment. A new sedimentological study performed on Erlian Formation drill cores has led to the determination of an architectural model and to the subsequent characterisation of the stratigraphic evolution of this sedimentary unit during the late Cretaceous. The palynological occurrences that were identified in samples provided a possible stratigraphical age for the Erlian Formation.Sediments of the Erlian Formation occur at the top of the Cretaceous stratigraphic column of the Erlian Basin and were deposited during the post-rift stage. Facies architecture and the ideal succession of facies that were identified for this formation exhibit two different members, both dominated by a fluvial depositional environment: (i) the lower member, which is dominated by channels of a braided river system and (ii) the upper member, which is dominated by overbank deposits. The lower member expresses a tectonically induced uplift as indicated by channels clustering under negative accommodation, whereas a period of stratigraphic base-level rise that is associated with an increase of accommodation is identified in the upper member. Therefore the Erlian Formation highlights an alternation of short uplifts that were dominated by braided fluvial channel deposits with periods of stratigraphic base-level rise that were dominated by overbank deposits. This sedimentological architecture has significant metallogenic implications for the origin of confined permeable sandstone layers, which represent adequate host-rocks for roll front-type uranium deposits.The palynological assemblage Exesipollenites, Ulmipollenites/Ulmoideipites, Buttinia and Momipites that were recognised in two samples of the Erlian Formation has revealed a post-late Campanian age therefore more likely indicating a late Cretaceous age of deposition for the sediments of the Erlian Formation.     

Sedimentology of the upper Karoo fluvial strata in the Tuli Basin, South Africa

The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) may be grouped in four stratigraphic units: the basal, middle and upper units, and the Clarens Formation. This paper presents the findings of the sedimentological investigation of the fluvial terrigenous clastic and chemical deposits of the upper unit. Evidence provided by primary sedimentary structures, palaeontological record, borehole data, palaeo-flow measurements and stratigraphic relations resulted in the palaeo-environmental reconstruction of the upper unit.The dominant facies assemblages are represented by sandstones and finer-grained sediments, which both can be interbedded with subordinate intraformational coarser facies. The facies assemblages of the upper unit are interpreted as deposits of a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the upper unit, the climate was semi-arid with sparse precipitation resulting in high-magnitude, low-frequency devastating flash floods. The current indicators of the palaeo-drainage system suggest flow direction from northwest to southeast, in a dominantly extensional tectonic setting.Based on sedimentologic and biostratigraphic evidence, the upper unit of the Tuli Basin correlates to the Elliot Formation in the main Karoo Basin to the south.     

Petrographic characterization of Khadsaliya lignites,Bhavnagar district,Gujarat

The petrological studies on Khadsaliya lignites from Bhavnagar district have been carried out for their microconstituent’s characterization. Quantitative estimation of macerals reveal, due to high amount of macerals of huminite group, that this lignite deposits has formed from forest dominated vegetation in a fast subsiding basin, experiencing almost uniform environmental conditions, with slight intermittent fluctuations. The rank based on R_{o max} % values indicates that lignites are less mature and have not reached the sub-bituminous stage of coalification as those of the lignites from Panandhro (Gujarat) and Neyveli (Tamil Nadu) fields. High pyrite content in the Khadsaliya lignite makes it not much suitable for combustion purpose.     

Cenozoic basin evolution of the Central Patagonian Andes: Evidence from geochronology,stratigraphy, and geochemistry

The Central Patagonian Andes is a particular segment of the Andean Cordillera that has been subjected to the subduction of two spreading ridges during Eocene and Neogene times. In order to understand the Cenozoic geologic evolution of the Central Patagonian Andes, we carried out geochronologic(U-Pb and⁴⁰Ar/³⁹Ar), provenance, stratigraphic, sedimentologic, and geochemical studies on the sedimentary and volcanic Cenozoic deposits that crop out in the Meseta Guadal and Chile Chico areas(～47°S). Our data indicate the presence of a nearly complete Cenozoic record, which refutes previous interpretations of a hiatus during the middle Eocene-late Oligocene in the Central Patagonian Andes. Our study suggests that the fluvial strata of the Ligorio Marquez Formation and the flood basalts of the Basaltos Inferiores de la Meseta Chile Chico Formation were deposited in an extensional setting related to the subduction of the Aluk-Farallon spreading ridge during the late Paleocene-Eocene. Geochemical data on volcanic rocks interbedded with fluvial strata of the San Jose Formation suggest that this unit was deposited in an extensional setting during the middle Eocene to late Oligocene. Progressive crustal thinning allowed the transgression of marine waters of Atlantic origin and deposition of the upper Oligocene-lower Miocene Guadal Formation. The fluvial synorogenic strata of the Santa Cruz Formation were deposited as a consequence of an important phase of compressive deformation and Andean uplift during the early-middle Miocene. Finally, alkali flood basalts of the late middle to late Miocene Basaltos Superiores de la Meseta Chile Chico Formation were extruded in the area in response to the suduction of the Chile Ridge under an extensional regime. Our studies indicate that the tectonic evolution of the Central Patagonian Andes is similar to that of the North Patagonian Andes and appears to differ from that of the Southern Patagonian Andes, which is thought to have been the subject of continuous compressive deformation since the late Early Cretaceous.     

Fluvial sedimentation in the lower carboniferous of Clew Bay,County Mayo,Ireland

A succession of about 300 m of fluvial sediments from the Lower Carboniferous of northwest Ireland is described and interpreted. A lower, mainly red, formation contains fluvial channel deposits dominated by flat laminated sandstone. These are separated by interbedded sandstones and mudrocks with local caliche horizons and abundant mudcracks interpreted as levee and flood basin deposits. An upper, mainly non-red, formation contains fluvial channel deposits with common trough cross-stratification and epsilon cross-stratification also separated by interbedded sandstones and mudrocks. Evidence of desiccation is less common in the uppermost beds which pass transitionally upwards into marine sediments.The change in fluvial channel style is interpreted as due to increasing sinuosity and permanence of flow which may have been partly temporally and partly spatially controlled. The predominance of coarse sediments is thought to be largely controlled by limited subsidence. The Lower Carboniferous transgression was the major overall control of alluviation.     

Facies pattern of the middle Permian Barren Measures Formation, Jharia basin, India: The sedimentary response to basin tectonics

In the Lower Gondwana succession of the Jharia basin of eastern India, the Barren Measures Formation is characterized by the cyclic disposition of fine-grained lacustrine deposits and relatively coarse-grained fluvial deposits. The cyclic variation in the rate of coarse clastic input is attributed to the sedimentary response to basin tectonics. The sandstone-shale alternations of the Barren Measures succession can be correlated with the tectonic cyclothems developed on the hangingwall dip-slope and adjoining trough in a continental half-graben setting. Enhancement of the gradient of the hangingwall dip-slope during reactivation of the basin margin faults led to progradation of the existing fluvial system towards the half-graben trough and deposition of the coarser clastics on the fine-grained lacustrine deposits of the trough. Peneplanation of the hangingwall slope and slow increase in the lake level caused lacustrine transgression and retrogration of the fluvial system on the hangingwall block. The fluvial sediments were onlapped by the fine-grained lacustrine deposits. Episodic rejuvenation of the basin margin faults thus caused development of tectonic cyclothem on the hangingwall block. The paleocurrent pattern indicates that a persistent northward paleoslope was maintained during Barren Measures sedimentation. The inferred depositional settings were much more extensive than the present limit of the outcrop. The faults, presently defining the northern limit of the Barren Measures Formation, were possibly emplaced after Barren Measures sedimentation. The final movement along these fault planes caused preservation of the downthrown hangingwall block and the Barren Measures sediments on the footwall block were eroded during subsequent denudation. The Southern Boundary Fault came into existence after the deposition of the Barren Measures sediments.     

The Late Triassic Sequence-Stratigraphic Framework of the Upper Yangtze Region, South China

In the transitional period between the Middle and the Late Triassic, the Indochina orogeny caused two tectonic events in South China: (1) the formation and uplift of the Qinling-Dabie orogenic belt along the northern margin of the South China Plate, due to its collision with the North China Plate; and 2) the development of a 1300-km-wide intra-continental orogen in the southeastern part of the South China Plate, which led to a northwestward movement of the foreland thrust-fold zone. These tectonic events resulted in the ending of the Yangtze Platform, and were a stable paleogeographic factor from the Eidacaran to the end of the Middle Triassic. This platform was characterized by the widespread development of shallow-water carbonates. After the end of the Yangtze Platform, the upper Yangtze foreland basin (or Sichuan foreland basin) was formed during the Late Triassic and became a accumulation site of fluvial deposits that are composed of related strata of the Xujiahe Formation. In western Sichuan Province, the Xujiahe Formation overlies the Maantang Formation shallow-water carbonate rocks of the Xiaotangzi Formation siliciclastic rocks (from shelf shales to littoral facies). The sequence-stratigraphic framework of the Upper Triassic in the upper Yangtze foreland basin indicates a particular alluvial architecture, characterized by sequences composed of (1) successions of low-energy fluvial deposits of high-accommodation phases, including coal seams, and (2) high-energy fluvial deposits of low-accommodation phases, including amalgamated river-channel sandstones. The spatial distribution of these fluvial deposits belonging to the Xujiahe Formation and its relative strata is characterized by gradual thinning-out, overlapping, and pinching-out toward both the east and south. This sedimentary record therefore expresses a particular sequence-stratigraphic succession of fluvial deposits within the filling succession of the foreland basin. The sequence-stratigraphic framework for the Upper Triassic in the Upper Yangtze region provides a record of the end of the Yangtze Platform and the formation of the upper Yangtze foreland basin.     

Palaeoenvironmental significance of the clay mineral composition of Olduvai basin deposits,northern Tanzania

Quaternary deposits in the southeastern part of the Olduvai basin, northern Tanzania, consist of lake margin deposits, followed by a series of fluvial sediments. The clay mineral fraction of the lake margin deposits (Bed I and lower part of Bed II) is composed of smectite and subordinate illite. All smectite is largely dioctahedral and shows indications for a limited degree of irregular interstratification by illite. In the overlying fluvial deposits (Beds II–IV), illite is the most abundant clay mineral. Smectite only occurs in lower parts of the fluvial deposits (up to the middle of Bed III), where it generally shows a high degree of irregular interstratification. Differences in clay mineral composition between the lake margin deposits and the fluvial deposits record differences in sediment source area and degree of alteration. Dioctahedral smectite in the lake margin deposits and the oldest fluvial deposits is derived from a region with volcanic material extending to the east and south of the basin, which also supplies a certain amount of illite. Illite in the fluvial deposits of Bed IV originates from an area with a metamorphic bedrock to the west and north. Alteration of detrital clay minerals resulted in Mg-enrichment of dioctahedral smectite in part of the lake margin deposits and partial illitization of smectite in the older fluvial deposits. Formation of clay minerals during diagenesis or soil development is not documented by analysis of the total clay fraction.     

西藏札达盆地上新统古格组和托林组的厘定与层序地层划分

根据札达盆地剖面中地层的接触关系、沉积旋回、沉积体系和岩相岩性特征,可将上新统河湖相地层划分为2个组、5个沉积相、8个岩段。古格组(N22g)一岩段为砾岩,属河流相沉积;二、三、五岩段以细碎屑岩为主,属浅湖相沉积;四岩段以含粘土质细碎屑岩为主,属深湖相沉积。托林组(N21t)一、二、三岩段为一套砾岩、含砾中粗粒钙质长石岩屑砂岩和中细粒砂岩的碎屑岩,为典型冲(洪)积扇沉积物。ESR法和古地磁法测年结果表明,古格组形成时代为上新世晚期(4.40～2.47Ma);托林组形成时代为上新世早期(5.44～4.40Ma)。札达盆地为一同生断陷盆地,在上新世时期的构造运动过程中,盆地演化经历了水进体系域—湖泊扩张体系域—湖泊收缩体系域3个发展阶段。     

Geochemistry of Quaternary sediments of the Jeongokri archaeological site,Korea: implications for provenance and palaeoenvironments during the Late Pleistocene

The geochemical characteristics of an approximately 6‐m‐long sediment core collected from the Jeongokri archaeological site (Hantan River, Korea) were examined to determine the provenance of the sediments and to reconstruct the palaeoenvironment of the study area during the Late Pleistocene (200–127 ka). The core sediments were subdivided into two parts based on grain size: an upper (0–380 cm depth) and lower part (>380 cm depth). The lower part was deposited primarily by fluvial processes during an interglacial period [marine isotope stage (MIS) 7] with warm and humid conditions. Conversely, the upper part was mainly deposited by aeolian processes during a cold and dry glacial period (MIS 6). Geochemical characteristics, represented by major, trace and rare earth element (REE) compositions, and textures of the Jeongokri core sediments show distinct differences between the upper and lower parts. The mineralogy and major, trace and REE compositions indicate that the influence of felsic source rocks (e.g. granite) was dominant in the lower sediments, which were derived from the Hantan River. In contrast, increased quartz content and the very fine and homogeneous grain size in the upper sediments indicate an aeolian origin. REE ratios and distribution patterns, and geochemical signatures indicate that these sediments were derived predominantly from Chinese loess deposits and partially from local sediments from the Korean Peninsula; the possible source area of the upper sediments is the northern part of the Yellow Sea basin. The Yellow Sea basin, having mixed geochemical signatures between Chinese loess and Korean‐derived sediments, was exposed because of low sea levels during MIS 6. The exposed Yellow Sea basin was located in the path of winter‐monsoon winds, which may have carried a great deal of airborne sediments from the basin to the Jeongokri area. Copyright © 2011 John Wiley & Sons, Ltd.     

Stratigraphy and architecture of the Upper Triassic Ischigualasto Formation,Ischigualasto Provincial Park,San Juan,Argentina

The Ischigualasto Formation in northwestern Argentina contains abundant fluvial channel sandstones, overbank mudstones, and paleosols that were deposited in a northwest-trending continental-rift basin during Late Triassic time. In the study area the formation progressively thins from ～700 m in the west to ～400 m in the east, over a distance of 7 km. This thinning is accompanied by a relative decrease in the abundance of fluvial channel sandstones and an increase in mud-rich overbank deposits and paleosols. While preserved channel deposits in the formation are highly variable in terms of their size and stratigraphic distribution, four general channel forms can be recognized based on their overall cross sectional geometry and internal sedimentary structures. Of these, the dominant channel-body types are interpreted as the deposits of sandy multi-channel fluvial systems. The internal stratigraphic architecture of the Ischigualasto Formation indicates that during deposition, the central part of the basin was the location of a long-lived, north flowing, fluvial channel belt that received relatively continuous channel and proximal overbank deposition. To the east, however, channel-related deposition was more infrequent, resulting in enhanced pedogenic modification of alluvial deposits. The overall thickness and facies trends observed in the Ischigualasto Formation most likely correspond to variations in fault-related accommodation development within the basin during the time of deposition.     

华北地台区古近纪—新近纪岩相古地理特征

华北地台区古近系—新近系在渤海湾盆地非常发育,在南华北地区也有较大厚度,而在鄂尔多斯盆地则不甚发育,仅在西北部有少量沉积。渤海湾盆地古近纪以断陷型沉积为主,主要为滨浅湖相沉积,物源来自多个方向,如北部的燕山褶皱带、西部的太行山隆起、南部的鲁西隆起、东部的辽东隆起区以及盆地内部的沧县隆起和埕宁隆起等。南华北地区古近纪发育大小不一多个沉积中心,以河流相沉积为主;鄂尔多斯盆地古近纪仅在西北部出现沉积,发育河流相,缺失古新统—始新统沉积。新近系沉积区主要位于渤海湾盆地、南华北地区以及鄂尔多斯盆地外围的地堑中,主要为河流相和滨浅湖相沉积。新近纪早期渤海湾盆地大面积隆升,导致湖盆收缩,部分地区遭受剥蚀夷平,中晚期盆地整体形成统一坳陷,主要为河流相沉积,局部发育滨浅湖相;南华北地区进入裂谷期后坳陷发育阶段,大面积接受沉积,主要发育河流相沉积。华北地台区西部沿鄂尔多斯盆地周缘形成了一套以河流相与滨浅湖相为主的山前盆地沉积。华北地台区古近纪—新近纪油气的有利勘探区域为渤海湾盆地。     

Evidence of lacustrine sedimentation in the Upper Permian Bijori Formation, Satpura Gondwana basin: Palaeogeographic and tectonic implications

The Upper Permian Bijori Formation of the Satpura Gondwana basin comprising fineto coarse-grained sandstone, carbonaceous shale/mudstone and thin coal bands was previously interpreted as the deposits of meandering rivers. The present study documents abundance of wave ripples, hummocky and swaley cross-stratification and combined flow bedforms in the Bijori Formation, suggesting that a significant part of the formation was deposited in a wave-agitated environment. Evidence of near-emergent depositional conditions provided by repeated occurrence of rootlet beds and hydromorphic paleosols, local flooding surfaces denoting rapid fluctuation of water level, occurrences of temnospondyl vertebrate fossils, and absence of tidal signatures and marine fossils suggest a lacustrine rather than marine depositional regime. Five facies associations recognised within the Bijori Formation are inferred to represent fluvial channels and associated floodplains (FA1), lake shorelines (FA2), subaqueous distributary channels and associated levees (FA3), waveand storm-affected delta front (FA4), and open lacustrine/lower shoreface (FA5) deposits. The planoconcave fluvial channel-fill sandbodies with unidirectional cross-beds are clearly distinguishable from the delta front bars that show a convexo-plan or bi-convex sandbody geometry and dominance of wave and combined flow bedforms. Some of the distributary channels record interaction of fluvial and wave-dominated basinal processes. Major distributary sandbodies show a north to northwest flow direction while wave-affected delta front sandbodies show very complex flow patterns reflecting interaction between fluvial discharge and wave processes. Wave ripple crest trends show that the lake shoreline had an overall east-northeast to west-southwest orientation. The lack of documented contemporaneous lacustrine or marine sediments in the Satpura Gondwana basin posed a major problem of basin-scale palaeogeographic reconstruction. The existence of Bijori lake solves the problem and the lake is inferred to have acted as repository for the contemporaneous alluvial drainage. Development of the large Bijori lake body implies generation of accommodation space exceeding the rate of sediment supplied and thus represents locus of high tectonic subsidence. Transition of fluvial sediments with red mudstone and calcareous soil profile in the lower part of the succession to carbonaceous shale and coal-bearing lacustrine sediments in the upper part, denote a change from a warm semi-arid climate with seasonal rainfall to a more humid one.