Vindhyan Supergroup Research Articles

Palaeolithic investigations at Morpani, Central Narmada Basin, India

Morpani is a recently discovered Palaeolithic complex in the central Narmada Basin (Madhya Pradesh, India), discovered during the course of field investigations carried out by the Narmada Basin Palaeoanthropology Project. This site is situated in a region of the Gondwana Supergroup formations, south of the Narmada River. Regions to the north of the river, dominated by rock outcrops of the Vindhyan Supergroup formation present a multitude of Palaeolithic sites, in stark contrast to the southern region, dominated by the Gondwana Supergroup and Deccan Trap formations. This site is one of the few Palaeolithic sites in this southern region, and this paper reports on the recent Palaeolithic investigations undertaken at the site and the results of the lithic analyses of the recovered lithic assemblage. These investigations were carried out to qualify the nature of the Palaeolithic occupation in this region, as well as probe into the possible factors for the underrepresentation of the archaeological record here, especially when juxtaposed to the rich archaeological context noted to the north of the river. Lithic analyses indicates that Morpani represents an expedient lithic assemblage, located along the banks and bed of an ephemeral stream channel, and in regions where suitable raw material clasts are available. More work and collections are needed to securely characterise and attribute the technological features of this Palaeolithic site.

Geochemistry of Neoproterozoic arenites from the Murwara area, Katni District, Madhya Pradesh: Implications for provenance, weathering and Tectonic Setting

Geochemical analysis in terms of major, trace and rare earth elements of the Neo-Proterozoic arenites of Rewa and Bhander Groups of the Vindhyan Supergroup from Murwara, Katni district, M.P., has been carried out to determine the provenance, weathering and tectonic setting. The arenites are rich in SiO2 content but less in Na2O, K2O and CaO contents, suggesting the dominance of quartz and less amount of feldspars and rock fragments. Geochemically, these rocks are classified as quartz arenites to sub litharenite to sub-arkose. The CIA (75-98) and PIA values for these arenites and A-CN-K diagram indicates a high intensity of weathering in the source area. High LREE/HREE ratios, negative Eu anomaly and La/Sc, Th/Sc, Th/Co and Cr/Th ratio values suggest felsic source of these arenites. The discriminant diagram for these arenites indicates a quartzose sedimentary provenance. Ni vs TiO2 and Th/Sc vs Sc bivariate plots indicate that the felsic rocks have been the source rock for these arenites. The discrimination diagrams based on log (K2O+Na2O) vs SiO2 and Fe2O3+MgO vs TiO2 contents show a passive margin setting. Whereas the results of new discriminant function multi-dimensional diagram for the high silica arenites reveals a change from collision to continental rift setting

Seismic-aseismic impact on marine depositional dynamics and sedimentary architecture: Study on multilayer-multiscale SSDS in Proterozoic Rohtas Limestone, India

The present study explores a diverse suite of soft-sediment deformation structures (SSDSs) preserved at multiple levels within the Mesoproterozoic carbonate succession of Rohtas Limestone in the Vindhyan Supergroup of India. The carbonate succession shows lithological heterogeneity, characterized by a sharp change of facies association and depositional environment. Three layers of SSDS, traced over 57 km, demarcate the lower lagoonal from upper open shelf deposits. Contorted laminae, load casts and flame structures, convolute laminae, ball and pillow structures, accordion folds and pillar structures within the limestone beds infer liquefaction-fluidization and plastic deformation. The lateral continuity, vertical repetition and confinement of SSDS beds at the interface of lagoon and open shelf deposits indicate the role of seismicity on facies succession. The SSDS beds show lateral variation in thickness and structures, depending on the distance from epicenter. The seismic trigger was accompanied by sudden deepening of the depositional environment and related marine transgression. The coarsening up packages within the lagoonal succession comprise load cast and flame structures, syn-sedimentary faults and intraclastic conglomerates. The open shelf succession shows several fining up cycles, with multiple load and flame structures with intraclastic conglomerate at the top. Origin of SSDS in association of the coarsening up sequence, and fining up cycle infers that intrabasinal tectonics and storms were the triggering agents for lagoon and open shelf successions respectively. The seismite in the studied succession not only reveals the seismicity during the Proterozoic, but also changed the sedimentary facies association, which may use as a diagnostic criterion for the identification of seismite. This study also highlights that seismic and aseismic impacts on sedimentary architecture and paleoceanography evolution.

Geochemistry of Palaeoproterozoic Kajrahat Limestone, Vindhyan Supergroup, central India: insights into depositional conditions and sources of rare earth elements

Geochemistry of Palaeoproterozoic Kajrahat Limestone, Vindhyan Supergroup, central India: insights into depositional conditions and sources of rare earth elements

Bijoliya Vindhyan Supergroup Sandstone Region of Rajasthan, India: Conservation of Geoheritage and Geotourism

Bijoliya Vindhyan Supergroup Sandstone Region of Rajasthan, India: Conservation of Geoheritage and Geotourism

A synergistic approach to morphotectonic evolution for watershed management in the Bearma River Basin, Central India

Abstract Environmental catastrophes on a global scale have prompted a thorough evaluation of river morphology for sustainable basin development methods. Geomorphological investigations of river basins can provide significant information regarding Quaternary tectonic deformations. The present investigation intends to reveal tectonic imprints in the Bearma River Basin (BRB). Bearma is a significant river in central India that flows through Vindhyan Supergroup, Lameta, and Deccan Trap and contributes to developing the architecture of the marginal Gangetic plain. The digital elevation data has been utilized to obtain the morphotectonic indices, tectonic activity classes, and topographic characteristics. Bearma is an elongated basin with uplifted topography, continuously migrating channels, high hypsometric integral, and several stream length-gradient anomalies, indicating tectonically controlled. According to the tectonic activity index, 15.33%, 38.99%, and 46.55% areas of the BRB have high, moderate, or low tectonic activity, respectively. In conjunction with field investigations, the topographic and lineament study of the BRB has revealed significant relief variations and the importance of tectonic activity over erosion and depositional processes in determining the landscape. Reactivation of basement faults and subsurface lineaments caused by Himalayan tectonics and the Narmada Son North Fault have resulted in the recent deformation and development of the hydrographic network.

Exploring Acheulean biface diversity in the central Narmada Valley, Madhya Pradesh, India

Central India occupies a pivotal place in the study of the Indian Palaeolithic. It is rich in Lower Palaeolithic records, with over 300 occurrences reported, and the region's antiquity is at least 800 Ka or older. The central Narmada Valley remains one of the crucial regions in Central India with a high frequency of Acheulean sites, which are primarily observed in the regolith deposits derived from the Vindhyan Supergroup. It is observed that most of the Acheulean sites are to the north of the Narmada River, and with fewer sites to the south. One possible reason could be that multiple hominin populations occupied this region, and the central Narmada Valley acted as a corridor for multidirectional movement in the past. This paper presents preliminary research on different lithic bifacial forms at various Acheulean sites in the central Narmada Valley. This study presents an analysis of 733 bifaces which are typologically divided into cleavers (57.1%), handaxes (35.1%) and miscellaneous (7.8%) specimens. The spatial distribution of these biface forms shows that cleavers are prominently present in the Northern zone, while handaxes are more prevalent in the Central zone. This research discusses various technological aspects of Acheulean bifacial technology in the central Narmada Valley and provides broad implications regarding the hominin occupation in the Indian Subcontinent.

High primary productivity in an Ediacaran shallow marine basin influenced by strong seasonal to perennial upwelling

AbstractA significant area of late Neoproterozoic–early Cambrian seafloor hosted a ferruginous to euxinic condition as a result of expanded primary productivity-driven pumping of organic matter into subsurface water column and weak water column mixing in the concomitant sea. However, the cause and extent of increased marine primary productivity during this time interval remain unknown. To estimate the primary productivity in a late Neoproterozoic sea, this study investigated the Sirbu Shale, Vindhyan Supergroup, for trace elements, organic carbon isotopes and total organic carbon (TOC). Among the trace elements, cadmium (Cd), known for extremely low concentration in crustal rocks but higher abundance in biogenic organic matter, was the key parameter in the palaeoproductivity estimation. The Cd enrichment in the Sirbu Shale samples is comparable to that in modern marine sediments of the oxygen minimum zones in Chilean margins, Arabian Sea and Gulf of California characterized by high primary productivity and seasonal upwelling. In terms of Cd enrichment, the lower section of the Sirbu Shale was deposited under suboxic conditions, while the upper section was deposited under a relatively less reducing condition. Cd/Mo ratios > 0.36 in the shale sample indicate that the palaeoproductivity was strongly influenced by the nutrient supply through sea-shelf upwelling. Using non-detrital enrichment of Cd in Sirbu Shale samples, we calculated that the TOC exported to the floor of Sirbu Shale palaeodepositional setting through primary productivity ranged from 0.71 to 10.16%.

Biotic vs abiotic origin of unusual features from Mesoproterozoic of Vindhyan Supergroup, India

Biogenic signatures in Precambrian rocks are often difficult to confirm and debatable. We present some unusual features associated with microbial-mat related structures (MRS) from the freshly-exposed rippled bed surface of 1.6 Ga old Chorhat Sandstone, Vindhyan Supergroup, India. The features discussed here, are present within intertidal to supratidal environments often affected by storms. One of the features includes ridge-groove couplets that run across the ripple crests. Locally, the ridge-groove couplet forms a braid-like pattern. Along the ripple troughs, the ridges are considerably long and maintain a uniform width on the mm scale. Another feature shows meandering grooves bordered by ridges. The grooves swerve, form loops, cut across older grooves, and branch up. None of them have comparable equivalents in the Precambrian record described thus far. The invariably uniform width of the ridges for both the two features cannot be compared with undersurface gas bubble migration, and the swerving and reversing nature of the grooves denies passive movement of any inorganic/organic masses under the influence of an external force. They seem to have been created by movement through a microbiota-rich surficial sediment. Such unusual features raise questions about the biosphere and biotic structures during the Boring Billion (1.8–0.8 Ga).

Dickinsonia tenuis reported by Retallack et al. 2021 is not a Fossil, Instead an Impression of an Extant ‘fallen beehive’ by S.K. Pandey, Shamim Ahmad and Mukund Sharma. Jour. Geol. Soc. India, v.99, 2023, pp.311-316

Abstract We consider existing reliable data indicate the depositional age of the uppermost sandstone (Maihar Sandstone) of the Vindhyan Supergroup to be closer to 1000 Ma. We consider the penultimate statement by Pandey et al. (2023) “… the Maihar Sandstone is deposited within the Ediacaran Period” (our italics) is erroneous. In this note, we address both the dubious geochronology and the dubious biostratigraphy called on by Pandey et al. (op. cit.), and comment on the impropriety of changing extant stratigraphy on the basis of either.

Soft-sediment deformation structures in the Mesoproterozoic Kaimur Sandstone, Vindhyan Supergroup (Central India), and their seismotectonic implications

The unequivocal identification of soft-sediment deformation structures (SSDS) is a significant attribute to constrain the effect of transient geological events in the spatio-temporal evolution of ancient sedimentary basins. This paper reports and discusses, for the first time, the occurrence of several cm- to dm-scale SSDS within sandstone successions of the Mesoproterozoic Kaimur Group (Vindhyan Supergroup), exposed at the Hanumandhara Hill of Chitrakoot-Satna border region, Madhya Pradesh State, India. The SSDS are confined to a deformed interval comprising seven individual sedimentary units of variable composition and texture, which are sandwiched between nearly horizontally undeformed sandstone beds. The SSDS consist of load structures (load casts, flame structures, pseudonodules and ball-and-pillow structures), contorted lamination, convolute lamination, boudins and pinch-and-swell structures, deformed cross-stratification, slump structures, clastic injections, fluid escape structures, and syn-sedimentary fractures/faults. The present study suggests that the formation of these SSDS is essentially related to a combination of processes (gravitational instability, liquefaction, fluidization, and fluid escape) predominantly induced by seismic shocks. In addition, the restricted occurrence of fractures/faults in these deformed layers emphasizes the passage of seismically-induced Rayleigh waves. Considering the observed types of SSDS, their lateral homogeneity and geographic distribution along with the geodynamic framework of the Vindhyan Basin, the whole area can be tentatively attributed to having experienced moderate- to high-magnitude (M ≥ 5) seismicity. The present study combined with earlier reports of seismically-induced SSDS, from other regionally disposed formations belonging to the Lower (e.g., Kajrahat Limestone, Chopan Porcellanite, Koldaha Shale, Rohtas Limestone, and Glauconitic Sandstone of the Semri Group) and Upper (e.g., Bhander Limestone of the Bhander Group) Vindhyan Supergroup, respectively, provides evidence for the constant regional-scale seismo–tectonic activity within the Paleo-Mesoproterozoic Vindhyan Basin. Importantly, this observation further suggests that the intracratonic basins can be active tectonically contrary to the earlier propositions.

Recent basement fault reactivation and fluvial drainage modification in an intraplate setting, eastern Bundelkhand Craton, Madhya Pradesh, India

North-central India is underlain by three northeast-trending paleo-topographic ridges of Precambrian Indian basement, bounded by lithospheric-scale basement faults. The Pokhara Fault defines the eastern edge of the Faizabad paleo-topographic ridge, which exposes the Archean Bundelkhand Craton. Near Panna, Madhya Pradesh, the Pokhara Fault coincides with a monocline developed in the Proterozoic Vindhyan Supergroup rocks along the Bundelkhand cratonic margin. Fluvial morphology of basins along the monocline, as well as a deeply incised abandoned meander preserved where the Ken River flows through the monocline, are investigated using longitudinal stream profiles and other geomorphic data along the length of the monocline to assess potential linkages with active basement fault reactivation.Normalized steepness indices in analyzed channel profiles along the monocline increase significantly downstream, with some channels exhibiting convex, over-steepened segments. Normalized steepness indices, knickpoint elevations, and incision depths are on average much higher in streams along the southwest segment of the monocline compared to streams along the northeast segment. Most channel profiles exhibit a knickpoint with slope-break morphology. The obtained longitudinal channel profiles exhibit characteristics of a fluvial system in a transient state subjected to an increase in rock uplift that intensifies to the southwest over a reactivated basement fault. Using previously published relationships between erosion rates and channel steepness, we conservatively estimate the onset age of monocline growth to be Plio-Quaternary. Fluvial geomorphic features preserved near Panna also suggest that the Ken River is an antecedent river. The incised meander feature near the crest of the monocline appears to be the abandoned river valley of a former Ken River course that was orphaned during the evolution of the landscape by what is now the present-day Ken River.Our study supports growing evidence that Indian basement faults such as the Pokhara Fault are long-lived and have recorded multiple periods of reactivation. Recent fluvial modification in the Panna region demonstrates that Indian basement faults are also active on the south side of the Ganga Basin, far south of the Himalayan deformation front, and may be linked to intraplate seismicity and active tectonic modification of the landscape.

A new palaeobiological assemblage from the Son Valley Bhander Group and its implications on the age of the upper Vindhyans of India

The present study discusses the biostratigraphically significant new fossil assemblage recovered from the three stratigraphic units of the Bhander Group of the Vindhyan Supergroup, exposed in the Son Valley, India. The assemblage comprises vase-shaped like microfossils (possible VSMs) — Cycliocyrillium simplex, C. torquata, Bonniea pytinaia, B. dacruchares, scale microfossils, and cyanobacterial forms recorded in black bedded/lensoid chert associated with the Bhander Limestone. Late Ediacaran Leiosphere Palynoflora (LELP) and other associated organic-walled microfossils (Leiosphaeridia spp., such as L. jacutica, L. crassa, L. tenuissima, L. minutissima, and Ostiana microcystis) are noted in the Sirbu Shale. Charniodiscus-like Ediacaran megafossil is recorded in the Maihar Sandstone the youngest litho-unit of the Bhander Group. An assemblage of possible VSMs, acritarchs, and Ediacaran-like megafossil compliments the previous reports of the Ediacaran-aged fossils, such as Arumberia banksi, Beltanelliformis minuta and other fossils recovered from the Bhander Group and used to constrain the age of the Bhander Group. The biostratigraphic significance of the fossil assemblage has been discussed. The present study provides a better age constraint of the Bhander Group suggesting that this group continuously received sediments for deposition into the Ediacaran Period (635–538 Ma).

Geochemistry of an intercalated unit of arkose and shale of the Dhandraul Formation belonging to the Vindhyan Supergroup, Eastern India: Insights from provenance, depositional environment, and geodynamic set-up

Geochemistry of an intercalated unit of arkose and shale of the Dhandraul Formation belonging to the Vindhyan Supergroup, Eastern India: Insights from provenance, depositional environment, and geodynamic set-up

Petrography and diagenesis of Neoproterozoic Bhander Sandstones, Vindhyan Supergroup, Southeastern Rajasthan, India: Implications for provenance and reservoir characteristics

Petrography and diagenesis of Neoproterozoic Bhander Sandstones, Vindhyan Supergroup, Southeastern Rajasthan, India: Implications for provenance and reservoir characteristics

Paleoproterozoic thick-skinned tectonics in the Central Indian Tectonic Zone: implications on the tectonic reconstructions of cratonic nuclei

ABSTRACT The Satpura Mountain Belt, or the Central Indian Tectonic Zone (CITZ), is a Paleoproterozoic mountain belt of Central India, with Mesoproterozoic and Neoproterozoic rejuvenation history. Structural studies carried out in the southern margin of this ancient orogenic belt have identified a two-phase evolution. The documentation of mapped fold interference of Type 2 ‘boomerang-shaped’ pattern and the spread of early lineations over the hinge area of second-generation folds provide an estimate of ~40-43° angle between the regional axial directions of the folds of the two orogenic episodes. The map patterns indicate the presence of basement-involved recumbent fold nappes placed above the sedimentary cover sequence. The identified décollement structure on the surface provides information regarding the deformation of the upper crust in ductile manner. The patterns of the deep crustal reflectors mapped through previous deep seismic reflection study interpreted during the present investigation brought out the thick-skinned deformation in the region as well as identification of crustal low-velocity zones of lower strength and a domal geometry of the lower crust. The regional thrusts are found to deform deeper crustal layers, one thrust affecting the crust-mantle boundary. The behaviours of the upper and lower crust in terms of rheological layering have been used to interpret the regional structural style of the lithosphere. The structural features of the region do not support the argument regarding the status of the Central Indian Shear as a suture, but indicate it to be the outermost emergent thrust towards the foreland side. The patterns of dip of the thrusts and thrust transport directions indicate a northward dip of the South Indian Block during the subduction stage and the position of the collisional suture of the Satpura orogen to the north of the Sausar belt. A tectonic model has been proposed here to explain the formation of the Satpura Mountain Belt or CITZ involving subduction-collision at ~2250 Ma, followed by erosion, stretching and basin development between 2100 and 1500 Ma. A collisional event in the eastern and western craton margins of India, at ~1500 Ma, caused the second uplift of the Satpura Mountain Belt and its northern margin, developing a temporal unconformity of ~300 Ma gap between the Semri and Kaimur Groups (Vindhyan Supergroup). A third event in the region at ~950 Ma was similar to the second event. No continental amalgamation took place along the CITZ during the tectonothermal events at ~1500 Ma and ~950 Ma; these involved reactivation of old thrusts and basal accretion which were the effect of far-field stresses emanating from the orogenic events at the eastern margin of the Bastar Craton and western margin of the Aravalli Craton.

Unravelling Source Area Composition for the Paleoproterozoic Basal Conglomerate (Vindhyan Supergroup) around Dalla, Sonbhadra District, Central India

Abstract The present investigation reveals that the Basal Conglomerate is ~ 2-3 m thick forming basal part of the Vindhyan Supergroup in the Sonbhadra district, central India. The Basal Conglomerate consists of fragments of different rock types supported by the sandy matrix. It contains pebble-sized clasts of quartzite, jasper, phyllite and slate dominated by the quartzite clasts.The matrix is composed of sandy material that is rich in quartz, chert and iron oxides. The occurrence of quartzite clasts suggests its derivation from the Chhotanagpur Granite Gneiss Complex (CGGC) and the phyllite, slate and jasper suggest their derivation from the Mahakoshal Group. The presence of polycrystalline and monocrystalline quartz suggests their derivation from Chhotanagpur Granite Gneiss Complex and the presence of chert suggests its derivation from the Mahakoshal Group. The iron oxides were produced as a result of leaching of iron during chemical weathering. The X-ray diffractometry of the matrix suggest ubiquitous presence of quarz, muscovite and kaolinite. The kaolinite has formed due to alteration of feldspars under warm and humid conditions. This is also supported by the presence of ferruginous matter in the matrix.

Geomorphic Analysis of Baghain River, Yamuna Basin, and its Implication for Drainage Characteristic and Tectonics using Remote Sensing and GIS Techniques

Abstract The present study aims to access the geomorphic analysis of the Baghain river basin and its implication on landscape evolution. Baghain river originates from the Panna hill, and flows through marginal and central Ganga plain. It empties itself in to Yamuna river near Chilla village, Banda district, Uttar Pradesh. The river basin comprises of three major geological units associated with this basin: Bundelkhand gneissic complex, Vindhyan Supergroup (hard rock terrain known as Panna hill) and Alluvial deposit (marginal Ganga plain and central Ganga plain). The current work focuses on study of morphometric parameters and geomorphic indices of Baghain river basin using digital elevation model (DEM) and topographic maps (1:50,000 scale). This basin exhibits four types of drainage patterns: dendritic, parallel, trellis and rectangular. Bifurcations ratio (4.82) of river basin suggest that the most part of the basin is not influenced by any geological structures. The elongation ratio (0.50) suggests that the basin is moderately elongated. The drainage density (0.62) and stream frequency (0.22) also suggest that the basin has moderate to high permeable and easily erodible alluvium terrain. The escarpment height is low in the proximal part (Panna Hill) and high in the middle and distal parts of the basin (marginal Ganga plain and central Ganga plain, respectively. Asymmetric factor (52) shows a leftward tilt of the basin. The region lies under marginal Ganga plain, and Bundelkhand plateau. The sharp bend present is probably due to the lithological variation. It reflects moderate gradient in the upper part (Panna hill), steep gradient in the lower part (Panna hill), and low gradient in the marginal to central Ganga plain.

Newly discovered ca. 1.6 Ga K-bentonite layers from the Lakharpata Group in Nepal Lesser Himalaya: Implications for basin evolution during the Columbia breakup

• Zircon U-Pb age for newly discovered K-bentonite (ca. 1.6 Ga) constrained the deposition time of the Lakharpata Group. • The Lakharpata Group in Nepal Lesser Himalaya is coeval sediment with the Lower Vindhyan in India. • The Lakharpata Group was deposited in a passive continental margin basin during the Columbia breakup. The Lakharpata Group, a set of marine sediments with a thickness of over 5000 m, occupies the middle part of the Lesser Himalayan sequence and records important tectono-sedimentary evolution in the northern margin of the Indian continent. However, the duration of deposition and tectonic background of the Lakharpata Group are poorly defined. This study presents zircon U-Pb ages and Hf isotopes, as well as petrochemical data for the newly discovered K-bentonite layers in the Aru Formation, the upper part of the Lakharpata Group. Integrating the detrital zircon ages of the underlying metasedimentary rocks and the sedimentation rate of dolomite in the South China Block, we suggest that the Lakharpata Group was deposited during the late Paleoproterozoic to early Mesoproterozoic (ca. 1680–1580 Ma) rather than from Mesoproterozoic to Early Paleozoic as previously presumed. Stratigraphic correlations show the Lakharpata Group in Nepal Lesser Himalaya correlates to the Lower Vindhyan Supergroup, as well as to the Deoban and Rautgara formations in Kumaun Lesser Himalaya and the Baxa Group in Sikkim Lesser Himalaya, India. The Lakharpata Group comprises two depositional sub-sequences that record two transgression-regression sedimentary processes, which are comparable to the Lower Vindhyan. Geochemical and sedimentological studies suggest that the Lakharpata Group may represent the deposition of a passive continental margin basin during the breakup of the Columbia supercontinent.

Organic Matter (OM) Associated Uranium Mineralisation in Kaimur Group of Vindhyan Supergroup near Maha-Rampura, Gwalior District, Madhya Pradesh, India

Abstract The Proterozoic Vindhyan Supergroup overlying Bundelkhand Granite Complex (BGC) presents an ideal environment for exploration of uranium mineralisation. Recent exploratory drilling in Kaimur Group of sandstone overlying unconformably the basement Bundelkhand granite at Maha Rampura area has revealed a significant correlatable uranium mineralisation. The mineralisation hosted by subfeldspathic arenite with reddish/ greenish shale intercalations enriched with organic matter is delineated. The subfeldspathic arenite has a definite marker bed with 1-2 m thickness located ~ 30 m to 40 m above the unconformity. Organic matter (OM) is disseminated in subfeldspathic arenite and occurs within intergranular spaces as rounded globules. Uranium occurs within the subfeldspathic arenite as primary minerals i.e. uraninite and coffinite as well as in adsorbed form on organic matter and clay within the marker horizon. Significant correlatable uranium mineralisation with primary uranium minerals in Maha Rampura area thus opens up a broad exploration target in the entire Vindhyan Basin.