Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

S. Kumar ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226 007, IN

Abstract

Nine samples of sparry magnesite and five samples of dolostone of the Mesoproterozoic Gangolihat Dolomite (Formation) of the Chandak area, Pithoragarh are analysed for stable isotopes of carbon and oxygen. δ¹⁸O for dolostone varies from -10.8‰ to -9.0‰ (SMOW) with mean as -10.1‰ (SMOW) and for magnesite it varies from -16.8‰ to -11.8‰ (SMOW) with mean as -14.0‰ (SMOW). δ¹³C for dolostone varies from -1.6‰ to 0.6‰ (PDB) with mean as -0.0‰ (PDB) and for magnesite it varies from -2.2‰ (PDB) to 0.1‰ (PDB) with mean as -1.0‰ (PDB). Thus, magnesite and dolostone show distinctly different isotopic signatures and hence magnesite must have formed from isotopically different fluids than those which produced dolostones. Magnesite is not syndepositionally produced but must have formed at some later stage by hydrothermal solutions.

Keywords

Economic Geology, Magnesite, Dolostone, Mesoproterozoic, Isotopes, Uttar Pradesh.

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V. J. Gupta ¹, P. C. Bisaria ¹, D. K. Chadha ¹, G. Mahajan ¹, S. Kumar ¹, S. R. Kashyap ¹, N. Kochhar ¹, N. S. Virdi ¹

Affiliations
1 Centre of Advanced Study in Geology, Panjab University, Chandigarh, IN

Abstract

No Abstract.

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I. B. Singh ¹, S. Kumar ¹

Affiliations
1 Geology Departrnent, Lucknow University, Lucknow-226007, IN

Abstract

The lower Vindhyan sediments of Chitrakut area (Chitrakut Formation-Semri Group of Son Valley) are deposits of a tidal swept shallow sea, mainly in tidal flats under extremely stable conditions. They represent a special case of condensation horizons (condensed deposit) under conditions of exceptionally low rates of deposition and negligible sinking of the basin. The stromatolite assemblage suggests lower Riphean age and can be correlated to the Kajrahat limestone of Son Valley area. A marked depositional hiatus is established at the base of Kaimur at Sangrampur hill. Variation in the facies and absence of time plane index-horizons makes the correlation in the Chitrakut area very difficult. It is too early to suggest a generalized lithostratigraphy for the Chitrakut Formation.

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S. Kumar ¹, K. K. Tandon ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow, IN

Abstract

Well preserved Ichnogenus Ophiomorpha Lundgren and Thalassinoides Ehrenberg are recorded from the Mottled Nodular Sandstone Member of the Lameta Formation. The Thalassinoides type burrows are also quite common in the Upper Limestone Member and Upper Sandstone Member. On the basis of the presence of trace fossils and primary sedimentary structures it is concluded that the Jabalpur Formation and Green Sandstone Member of the Lameta Formation are fluvial deposits.

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S. Kumar ¹, V. C. Tewari ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow-226007, IN

Abstract

This paper records the occurrence of Conophyton garganicus from the Gangolihat Dolomites of the Calc Zone of Pithoragarh. On the basis of the presence of Conophyton garganicus, the correlation of Gangolihat Dolomites is discussed.

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S. Kumar ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226 007, U.P., IN

Abstract

The Lower Vindhyan stromatolites are dominantly made up of dolomite while the Upper Vindhyan stromatolites are made up of calcite. Sr shows sympathetic relationship with CaO and K₂O with Al₂O₃. Three distinct assemblages of stromatolites belonging to the Kajrahat Limestone, the Fawn Limestone and the Bhander Formation show different trace element distribution.

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S. Kumar ¹, Purnima Srivastava ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow, IN

Abstract

The black bedded-chert at the base of the Lower Vindhyan succession in Chitrakut area, exposed at the southern face of Sangrampur Hill shows good preservation of microorganisms in the petrographic thin sections. The chert is not associated with stromatolites. Unusually large coccoid Trachysphaeridium sp. Timofeev and filamentous forms showing branching are recorded.

Keywords

Vindhyan Basin, Chitrakut, Uttar Pradesh, Palaeontology, Proterozoic.

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S. Kumar ¹, Vibhuti Rai ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226007, IN

Abstract

Well preserved microfossils are reported from petrographic thin sections of the bedded black chert from the Krol 'A' Member of the Krol Formation near Solan. Himachal Pradesh. Filamentous forms comparable to Eomycetopsis Schopf, Siphonophycus Schopf, Obruchevella Reitlinger and coccoid forms represented by acritarchs and spheroid colonies showing resemblance with living cyanobacteria Microcystis Kutzing are recorded. The presence of forms comparable to Obruchevella suggests Upper Riphean to Vendian age to the Krol 'A' Member.

Keywords

Precambrian, Microbiota, Krol-Belt, Krol Formation, Obruchevella.

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Ashok K. Srivastava ¹, S. Kumar ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow - 226 007, IN

Abstract

Trace fossils namely, Arenicolites, Monocraterion, Planolites,lchnogenus A, and trails are recorded from the Muth Quartzite of the Malla Johar area of the Kumaon Himalaya. The trace fossils are recorded dominantly from the middle unit i.e., Muth B Member. On the basis of ethology and preservational conditions it has been interpreted that during the deposition of the Muth B Member, the benthonic community was dominated by molluscs and polychaetes. The organisms producing trace fossils are dominated by feeding or feeding-dwelling habitat.

Keywords

Trace Fossils, Muth Quartzite, Himalaya, Palaentology.

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S. Kumar ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow, U.P., IN

Abstract

In the Tirohan Limestone (Formation), collophane is associated with stromatolite-bearing horizon near Janaki Kund, Chitrakut area, Madhya Pradesh. It occurs as pellets, stromatolite laminae and as an envelope around stromatolites. The collophane is identified as carbonate fluorapatite which is confirmed by cell dimensions with a (Å) = 9.3638 and c (Å)= 6.8934. The C0₂ content is 1.80%, δ¹³C (organic), value for collophane is -21.99 PDB. The apatite does not show any correlation with any major or minor elements except with Ca with which it has poor positive correlation. It is envisaged that the apatite must have been formed on the stromatolite surfaces below sedirnent/water interface by the activity of microorganisms dominated by sessile bacteria.

Keywords

Geochemistry, Phosphatic Carbonates, Chitrakut Area, Vindhyan Supergroup, Central India, Stromatolite.

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R. K. Samadder ¹, S. Kumar ², R. P. Gupta ¹

Affiliations
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee - 247 667, IN
2 National Institute of Hydrology, Roorkee - 247667, IN

Abstract

Study of aquifer geometry is essential for proper development and utilization of groundwater resources. In this study, a systematic approach has been made in the analysis of shallow aquifer geometry in the western Ganga Plains, Uttar Pradesh, by integrating the well-Log and remote sensing data. The study includes mapping of neotectonic lineaments from remote sensing data, and determination of aquifer depth and lithological details from the well-Log data. The well-Log data indicate that the region has varying thickness of alluvium composed of alternating sand, kankar and clay strata. By integrating the remote sensing and well-Log data sets, sub-Surface geological sections have been developed to interpret the aquifer geometry. The aquifers are found to show significant variation in nature and geometry from place to place. At some places, the lineaments on remote sensing images are in conformity with faults interpreted from well-Log data, whereas at others, buried faults have been interpreted. The aquifers formed by paleochannels is particularly striking, being unconfined in nature and mainly consisting of medium to coarse sand, along with pebbles, cobbles and kankar.

Keywords

Well-Log, Remote Sensing, Aquifer Geometry, Buried Faults, Lineaments, Paleochannel, Ganga Plains, Uttar Pradesh.

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S. Kumar ¹, A. Saxena ²

Affiliations
1 Centre of Advanced Study in Geology, University of Lucknow, Lucknow - 226 007, IN
2 SMEC India Pvt. Ltd., Gurgaon - 122 002, IN

Abstract

In the central part of Indo-Gangetic alluvium in the Unnao district, Uttar Pradesh there are many pockets where groundwater shows high fluoride content. Drinking of fluorinated ground water has effected a large population and in many villages more than 80% of the population is suffering from fluorosis. The source of this fluoride appears to be the alluvial sediments deposited in the geological past as no hard rock terrain is present in the nearby areas. The area is dominantly made up of mud with pockets of sand. The sand fraction is made up of quartz, plagioclase, microcline, muscovite and biotite along with some accessory minerals like garnet, epidote, chlorite, tourmaline, hornblende, kyanite and a few opaque minerals. Moreover, the fluoride content in the groundwater varies both spatially and with depth indicating a sporadic occurrence. The surface water is devoid of high content of fluoride but is reported in hand pumps and in the dug wells. This paper deals with the geochemical study of the sediments up to a depth of 45m as most of the hand pumps are up to this depth to understand the source of fluoride. ¹⁴C dates of calcretes have suggested that the 45 m thick succession must have been formed in about 45000 years.

Two different location sites were selected; one showing higher concentration of fluoride (Marksnagar village) while at other site which is about 4 km east of Marksnagar, the fluoride content was minimal (Durgajkhera village). Major elements and 24 trace elements were determined using XRF and it was found that when major elements are normalized with respect to upper continental crust (UCC) there is an enrichment of Si in all the samples. Na shows depletion where as Ti and K show enrichment. Fe and Mn show enrichment probably due to the formation of clay minerals. Si, and K enrichment is due to weathering of feldspar while Mg, Fe and K may have been released by the weathering of biotite. The CIA for the ancient sediments ranges from 54-64 while for the modern sediments of the Ganga River it varies from 50-64 indicating that there is no change in the rate of weathering in both modern and ancient sediments. The rate of weathering at all the sample locations was compared with that of UCC. The CIA values also suggest that there is an incipient weathering and indicate that the weathering of biotite is more progressive than muscovite. There is also a positive correlation between CIA values and the fluoride content in the ground water. Higher percentage of biotite and chlorite (altered biotite) was found at Marksnagar in comparison to Durgajkhera. It appears that the fluoride content in the ground water is due to dissociation/alteration of mica minerals mainly biotite.

Keywords

Groundwater, Chemical Weathering, Fluoride, Uttar Pradesh.

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