bluuebunny/crossref_metadata_2025 huggingface dataset:
Palaeocurrent Pattern and Provenance of a Part of Gondwana Succession, Talchir Basin, Orissa
Authors: Das Rajashree , Pandya K. L.
Published: November 2024

The Talchir Group and the Karharbari Formation including a Boulder Gravel Unit of Damuda Group had a predominant northerly palaeoflow with a radiating sediment dispersal pattern suggesting a transverse filling of the basin. In contrast, the Barakar sedimentation had a unidirectional northwesterly palaeoflow implying an axial filling. The sediments were largely derived from the Eastern Ghat source which occurs along the southern boundary of the basin. The Talchir Group represents a denudation phase of source area with declining relief manifested by a decreasing mean grain size and increasing complexity in the heavy mineral suite due to unroofing of low rank metamorphic rocks at the source. The Damuda Group represents a syn-and post-tectonic phase of sedimentation displaying differences in tectonic style manifested by source area uplift, basin subsidence and steepening of alluvial surface documented by upward increase in grain size, increased complexity in heavy minerals by exposure of high rank metamorphic rocks at source and post-tectonic drainage deflection towards northwest during Barakar sedimentation.
Effect of River Discharge on the Test Morphology of Benthic Foraminifera, Southeast Coast of India
Authors: Jayaraju N. , Reddi K. R.
Published: November 2024

Foraminifera, being extremely sensitive to ever changing marine microhabitat and ecosystem, can respond to and amplify even slight monsoonal rainfall fluctuations, particularly, near river mouth. The effect of river discharge on the test morphology of foraminifera has revealed high inertness of rounded symmetrical morpho-group to furious turbulences coupled with enormous fresh water influx. whereas negative trend is noticed with regard to angular-asymmetrical morpho-group. The results could be highly promising in reconstruction of paleomonsoonal history through morpho-group studies in the coastal fringe.
Chemistry of Garnet and Ilmenite from Majhgawan Diamondiferous Pipe, Panna District vis-a-vis Diamond Potential and Preservation
Authors: Mukherjee Abhijeet , Rao K. S. , Bandyopadhyay D. , Roy Gautam
Published: November 2024

The compositional trends in ilmenites from Majhgawan indicates slightly increased values of -log f02 i.e., 9.2. The divariant plots of Fe2O3 vs MgO and Cr2O3 vs MgO indicate resorption of most diamonds. The rounded-dedecahendra from indicates a preservation percentage of 65-70. The wine-red garnets from diamondiferous pipe are moderately subcalcic. The CaO vs Cr2O3 plot shows that they fall very close to the 85 percent Gurney line indicating emplacement at the craton margin having moderate diamond content. Geothermobarometry based on the co-existing pyropeknorringite and spinel geothermobarometer for the diamondiferous pipe yielded an equilibration temperature and pressure of 1160°C and 47 KbaT.
Criteria and Techniques of Detecting Site Specific Mechanisms for Artificial Recharge - A Case Study from Ayyar Basin, India
Authors: Ramasamy S. M. , Anbazhagan S.
Published: November 2024

The present paper narrates how various types of geological. structural, geomorphological and subsurface geological data have been collected and integrated in various pennutations and combinations to select suitable mechanisms for artificial recharge in Ayyar basin of Tamil Nadu.
First Record of Permian Palynofossils in Sub Surface Sediments of Cauvery Basin, India
Authors: Basavaraju M. H. , Govindan A.
Published: November 2024

A rich assemblage of radial monosaccate genera Parasaccites, Plicatipollenites, virkkipollenites.Potoneisporites associated with Trilete spores and Leiosphaeridia suggestive of Early Permian age have been recorded for the first time in well Pundi-B. Drilled in Cauvery Basin (Tanjore sub-basin).
Fluid Inclusion Study of Vein and Bedded-Type Barite of Cuddapah Basin, Andhra Pradesh
Authors: Mukherjee Abhijeet , Ballurkar Ashok
Published: November 2024

Fluid inclusion study is carried out on the vein and bedded-type barite of the Proterozoic Cuddapah basin of Andhra Pradesh. In the case of vein barite, primary inclusions are mostly monophase and liquid-rich biphase (L+ V), with their freezing temperatures indicating their composition as H2O+NaCI±KCl and density of the ore forming fluids as 0.901 to 0.944 g/cm3. The primary liquid-rich biphase (L+V) inclusions of the hydrothermal vein barite shows homogenization temperatures in the range of 230° to 260°C. The primary inclusions of the bedded (volcanogenic) barite deposits of Mangampeta are monophase carbonic with densities corresponding to 0.76 to 0.88 g/cm3. A conceptual mobilization-deposition model for the vein-type barite mineralization is given.
Numerical Classification of Coal-Bearing Cycles of Early Permian Barakar Coal Measures of Eastern-Central India Gondwana Basins Using Q-Mode Cluster Analysis
Authors: Tewari R. C.
Published: November 2024

Q-mode cluster analysis is applied to classify the fining upward cycles of Early Permian Barakar coal measures from 14 localities of eastern - central India Gondwana basins. Two distinct clusters are recognised on the basis of overall similarity of upward transition probability values of embedded Markov chain statistics. Cluster A comprise 9 localities representing fining upward asymmetrical cycles of very coarse to coarse sandstone ? interbedded fine sandstone-shale? shale ? coal ? coarse sandstone, whereas Cluster B include 5 localities represented by symmetrical cycles i.e. very coarse to coarse sandstone ? interbedded fine sandstone-shale ? shale ?coal ?shale.

The development of asymmetrical cycles together with abundance of very coarse to coarse sandstone is attributed to rapid lateral migration of braided channels, whereas the deposition of symmetrical cycles with subequal amount of coarse to medium sandstone and fine clastics including coal correspond to slow and gradual overstepping of meandering stream channels and associated subenvironments across the alluvial plain.
Gold Mineralization in Parts of Bundelkhand Granitoid Complex (BGC)
Authors: Pati J. K. , Raju S. , Mamgain V. D. , Shanker Ravi
Published: November 2024

Geological mapping in parts of Bundelkhand Granitoid Complex (BGC) reveals a number of E-W trending shear zones marked by mylonites. Synkinematic fluid activity along these shear zones is conspicuous. Anomalous gold values in the range of 5 and 1000 ppb in BGC is recorded against a background value of l to 2 ppb in most Precambrian granitoids.
Geochemistry of Late Proterozoic Sendra Granitoid Suite, Central Rajasthan, India : Role of Magma Mixing/Hybridization Process in their Genesis
Authors: Agrawal Salil , Srivastava R. K.
Published: November 2024

Cluster analysis based on major elements demonstrates existence of granite, granodiorite and tonalites as distinct natural sub-population in the Sendra granitoid suite. The peraluminous granite with limited variation in mineralogy and chemistry is characterised by higher total iron, K2O, mol. A/CNK, K2O/Na2O, Rb, Ba, Li and lower Sr as compared to the granodiorites and tonalites of the suite. Different trends for tonalites. granodiorites and granites in variation diagrams coupled with lower DI values of the granites in comparison to some of the tonalites and granodiorites, disallow interpretation of their relationship in terms of closed system equilibrium crystal fractionation or rcstite unmixing.

Principal component analysis of the data negates the possibility of the geochemical variations being controlled by a single process. The presence of mafic microgranular enclaves (MME) in the granodiorite and tonalite suggest mixing of the felsic and mafic magmas. The homogeneous nature of the granite and the absence of tonalitic and granodioritic components in the Chang pluton are due to emplacement of unadulterated granitic melt generated in the lower crustal region by basaltic underplating. The granodiorite and tonalite with variable chemical composition, represent subsequent mixing of granitic melt with the underplating basaltic magma and different degrees of thermal and chemical disequilibrium in the hybrid magma.
Some Contributions to the Lower Gondwana Stratigraphy of the Lpranhita-Godavari Valley, Deccan, India
Authors: Ray Sanghamitra
Published: November 2024

The "Infra-Kamthi" Formation is described from the central part of Pranhita-Godavari valley as an essentially sandstone rich horizon with subordinate amount of red mudstone in the lower part and highly ferruginous shale (ironstones) in the upper part of the rock succession. This formation is renamed here as Kundaram Formation, after the village Kundaram in its type area. The northwestern part of the valley has yielded the only known Late Permian reptilian fauna so far found in India.

The lithologs reveal a distinct lateral variation of the formation from the sand-dominant central Pranhita-Godavari to red mudstone rich horizon of the northwest. Ironstones are absent. Sheet sand bodies form composite complexes in the lower part of the rock succession followed upward by thick red mudstone units with small lenses of channel-fill sandstone. This package of sediments were probably deposited by anastomosing river channels.
Occurrence of Carbonatite at Chintalacheruvu, Guntur District, Andhra Pradesh
Authors: Veera Bhaskar D. , Thimmaiah M.
Published: November 2024

A new occurrence of carbonatite with significant radioactivity (0.038% eU3O8) and a conspicuous fenitised zone is being reported for the first time in the western peripheral parts of the Prakasam alkaline province, Andhra Pradesh. Besides U, the carbonatite is enriched in P, Fe, Ba, Sr, Ce and Y.
Earthquake Induced Liquefaction of Soil Near Elagiri Hills, Tamil Nadu
Authors: Pandian M. S. , Bhadra B. K.
Published: November 2024

Earthquake of magnitude 3.9 occurred in Tiruppattur area of Tamil Nadu on 31 January 1997. The epicentral location lies on a seismically active N45°E fault zone, along which many late Proterozoic alkaline intrusives are emplaced. The earthquake resulted in the opening of few fractures on the surface and as a secondary effect, induced liquefaction of soil at the base of Elagiri Hills. Excessive rainfall which preceded this event could have possibly played a role in causing the earthquake.
Sternet - A Computer Program for Stereographic Projection: With a New Algorithm for Contouring
Authors: Kutty T. S. , Joy Sojen
Published: November 2024

In the analysis of three dimensional data in geology, and their graphical representation, the use of spherical projections plays an important role. The Wulff and Schmidt nets, used commonly to plot such projections, are laborious and time consuming. Sternet is a fast, user-friendly, interactive program in Turbo C, for applications related to lower hemisphere projections. It can represent data as points or planes, rotate the data if necessary, draw the standard Pi-or Beta-diagrams, do contouring if the data is plotted as points, check for uniformity of the data and use eigenvectors and eigenvalues to draw a best-fit circle to the data if a preferred orientation exists and also provides a means to make one's own choice of a small or great circle to visually find a suitable fit for the data. The program includes a procedure for tilt correction and a few other utilities. Printer output is available for 24-pin dot-matrix printers.
Palaeomagma Chamber in the Upper Crust - Plausible Secondary Source for the Deccan Basalts of the Satpura Region in Central India
Authors: Venkata Rao K.
Published: November 2024

The Satpura ranges of Central India are mostly covered by Deccan Traps. Geophysical signatures over this region have been correlated and a crustal model has been arrived at. The areas of gravity high anomaly zones are characterized by deep depressions in the basement. 2-D gravity modelling studies indicate crustal underplating with magmatic additions in the crustal block. Modelling studies suggest the presence of high density bodies at a depth of 6 km in the gravity high anomaly zones of Khandwa and Tikaria. These bodies in the upper crust can be intermediate palaeomagma chamber/relic magma conduit forming a secondary source for the Deccan Basalts.
Flow of Groundwater in the Barind Area, Bangladesh: Implication of Structural Framework
Authors: Jahani Chowdhury Sarwar , Ahmed Mushfique
Published: November 2024

The structural framework in the Barind area, Bangladesh plays an important role in the regional flow of groundwater. The geological formations of the area are characterized by a series of faults and basement and geomorphic lineaments which form intrabasinal horsts and grabens and appear well correlated with the present day relief, topography and drainage pattern. The deeply incised eroded river valleys are grabens-representing stable and fault bounded blocks with corresponding horst blocks of the West, the Central and the Eastern Barind with different hydrogeological characteristics. The groundwater level, direction of flow and fluctuation pattern show the general trend of outflow towards the major rivers, streams and low-lying areas at the end of rainy as well as during dry season which almost follows the surface gradient of the area signify the seepage into the rivers.
Geochemistry of Granites of Jamhughoda, Panchmahals District, Gujarat and Uranium Mineralization in Champaner Group
Authors: Goyal Navin , Varughese Siby K. , Hansda P. K. , Ramachandran S. , Singh Rajendra
Published: November 2024

The Precambrian Champaner Group of rocks are intruded by Godhra granites in Jambughoda area. Significant uranium mineralisation has been located in the fractures in the dolomitic limestone of Lower Champaners with uraninite occurring as the primary uranium mineral. The geochemical features observed for the granites suggest that the granite melt, originated by the partial melting of relatively silicic crust, was further modified by fractionation processes during which uranium was concentrated in the late magmatic and subsequent hydrothermal fluids. The Champaner deformation resulted in the formation of WNW-ESE regional fracture system and crush zones, thus making the rocks highly penneable for the passage of uranium-rich hydrothermal fluids and offering open spaces for precipitation of uranium under suitable physicochemical conditions.
Crustal Reflectivity Parameter for Deciphering the Evolutionary Processes Across the Proterozoic Aravalli-Delhi Fold Belt
Authors: Tewari H. C. , Rajendra Prasad B. , Vijaya Rao V. , Reddy P. R. , Dixit M. M. , Madhava Rao N.
Published: November 2024

Deep Continental Reflection Studies along the Nagaur-Jhalawar profile across the Aravalli-Delhi Fold Belt indicate that in most of the units comprising the seismic profile the lower crust (LC) lies towards west of their present surface exposures. Based on the reflectivity characteristics of the LC. which are in general agreement with the globally accepted norms, the Nagaur-Jhalawal profile can be broadly divided into five zones: 1) the moderately reflective Marwar Basin (MB), 2) the highly reflective Delhi Fold Belt (DFB), 3) the poorly reflective Bhilwara Granite Complex (BGC), 4) the highly reflective Hindoli Group (HG) including a thrust zone, and 5) the moderately reflective Vindhyan Basin (VB). The most commonly accepted reasons for high lower crustal reflectively are: 1) presence of free fluids. 2) crustal-scale ductile shear zones and 3) mafic intrusions and underplating with partial melts derived from the upper mantle.

High reflectivity of LC in the ADFB can possibly be assigned to primary lithologic variation in the metamorphic facies layers and Precambrian shear zones that were formed during compressional phase of orogeny. The poor reflectivity of LC in the BGC. comprising the Sandmata and Mangalwar Complexes, may be due to vertically oriented igneous intrusions which have disturbed its lamellar character. The high reflectivity in the thrust zone and LC in the HG suggests that it is due to a totally different composition than that of BGC and may be related to metamorphic layering.
Calcretes : Geotechnical Appraisal and Efficacy as an Alternative Pavement Material for the Desertic Roads of Western Rajasthan
Authors: Ramakrishnan D. , Tiwari K. C.
Published: November 2024

Calcretes are widely distributed in the arid and semi-arid tracts of the Thar Desert. Strategically important roads of this desert region need a suitable, locally available paving material. Mineralogy, physical and geotechnical properties of calcretes indicate their suitability for road pavements.
Testimony of Intraformational Limestone Breccias on Lokapur-Simikeri Disconformity, Kaladgi Basin
Authors: Kale Vivek S. , Nair Sushma , Patil Shilpa
Published: November 2024

Detailed measurements of a more than 55 m wide tract of the Chikshellikeri Limestone, immediately underlying the Muchkundi Quartzite were undertaken in the Kaladgi Basin. This sequence is constituted of 3218 measured laminations from more than 1550 mudstone - packstone couplet. They are interrupted by 57 horizons of Intraformational Limestone Breccias. The distribution pattern of these horizons within the sequence is evaluated within the framework of the depositional environments which yielded the limestone sequence and they are recognised as products of events of penecontemporaneous basin-floor instability. It is shown that disconformity separating the Bagalkot Group into two Subgroups (earlier attributed to two separate transgresive events) was formed as a result of reorganisation of the basin configuration in response to synsedimentary tectonics and not as a result of a second transgression of the contemporary sea.
Saline Ground Water Management in Manda Thana of Naogaon District, NW Bangladesh
Authors: Woobaidullah A. S. M. , Ahmed K. M. , Hasan M. A. , Hasan M. K.
Published: November 2024

The study area is dependent on ground water for irrigation during the dry months of the year as sufficient surface water resources are not available. Occurrence of saline ground water in some parts of the area, particularly at Kashopara and Kasab unions. restricts the use of ground water for irrigation purposes. Ground water electrolytic conductivity (EC) monitoring and resistivity sounding show a distinct vertical ground water zoning with varying salinity, viz .. an upper zone (0-30 m) of relatively fresh Na/CaHCO3-type ground water with EC values <1000 μS/cm and a lower zone (below 30 m) of NaCI-type (brackish) ground water with EC values >2000 μS/cm. It is suggested that salinity prohlems in the affected area can be managed through minimum abstraction of saline ground water, proper selection of crops, land development and by changing methods of irrigation.
Palaeomagnetic Results from the Pleistocene-Holocene Lake Deposits of Bhimtal and Bhowali (kumaun Himalaya) and Lamayuru (Ladakh Himalaya) with Reference to the Reversal Events
Authors: Kotlia B. S. , Bhalla M. S. , Shah Nalin , Rajagopalan G.
Published: November 2024

Palaeomagnetic studies were carried out in the fluvio-Iacustrine sediments of Bhimtal and Bhowali basins (Kumaun Himalaya) and of Lamayuru basin (Ladakh Himalaya). The results were supplemented by radiocarbon dating. For the first time in the terrestrial sediments of the Quaternary-Holocene age in the Indian subcontinent, three minor reversal polarity events have been recorded at Lamayuru (ca. 35.5 ± 0.6 ka BP), Bhimtal (29.8-25.6 ka BP), and Bhowali (ca. 7.7 ± 0.13 ka BP). Since the upper most portion of the Lamayuru section indicated a reversal event, it may be significant to correlate it with the Indian Ocean event estimated as 40 ka BP. It is suggested that the Bhimtal event may be correlated with the widely known Mono Lake excursion which is fixed at 28-26 ka BP. Among the Holocene events, only a few are known, e.g., an event in the Solberga sediments (Sweden) estimated at ca. 10 ka BP; an event from Central Asia, dated at about 9 ka BP; the Erieau excursion, upper part of which has been estimated at about 7.6 ka BP; and the youngest event known as the Starno event (2.8 ka BP). The initial reports of the palaeomagnetic events, described in this paper, may be highly significant for examining several more sections as the events should he found repeatedly in sediments of same age in a given sedimentary environment.
Magnetostratigraphy of Fluviolacustrine Sediments from Pithoragarh Area, Uttar Pradesh
Authors: Bhalla M. S. , Kotlia B. S. , Subrahmanyam K.
Published: November 2024

Magnetostratigraphy of fluviolacustrine sediments from a 10 m thick section of a palaeolake near Wadda, Pithoragarh district, Uttar Pradesh bas been studied. The results indicate a prominent change in inclination of the remanent field in the age span 24 to 25 Ka, correlating with the widely known Mono lake excursion. Higher susceptibility values for the sediments of a part of the section are inferred to be due to rapid erosion rate associated with the transport of magnetite-rich sediments from the catchment area.
Calcareous Nannofossils Across the K/T Boundary and the Age of the Deccan Trap Volcanism in Southern India
Authors: Salis Katharina V. , Saxena R. K.
Published: November 2024

The distribution of calcareous nannofossils across the Cretaceous/Tertiary (K/f) boundary in well PLK-A in the Krishna-Godavari Basin of Southern India has been studied in the interval including sediments above, within and below the Deccan traps. With Micula murus present and M. prinsii missing, the presence of upper, but not uppermost Maastrichtian can be shown. The K/T boundary lies above trap flow 2 and the traps are overlain by sediments of the lower part of NP 3 (Danian). The span of volcanism has here probably lasted not more than 4 Ma.
Granites of Zoz Area, Baroda District, Gujarat and its Economic Significance
Authors: Maithani P. B. , Rathaiah Y. V. , Varughese Siby K. , Singh Rajendra
Published: November 2024

The granites around Zoz represent a differentiated, calc-alkaline, subaluminous, A-type granite with higher uranium content. The A-type affinity points to the possibility of encountering Sn, Mo, Bi, Nb, Ta and F mineralisation in the area. The low Th/U ratio also favours vein type U-deposits within granites or in adjacent metasediments.
Deformational History of Eastern Ghat Mobile Belt Around Lathore, Balangir District, Orissa
Authors: Biswal T. K. , Sanjeevan G. , Nayak B. P.
Published: November 2024

The calc-gneiss and garnet-sillimanite-gneiss of Eastern Ghat Mobile Belt around Lathore bear the imprint of multiple phases of deformtion. The folds of the first generation, F1, are isoclinal, intrafolial and vary in style from reclined to upright. This has developed a pervasive axial planar gneissosity. The second generation folds, F2 , which are coaxial with the F1 are open to tight with a planar axial surface dipping moderately to SE and varied plunging axis. At places mesoscopic plane non-cylindrical F2 sheath folds are noticed. Gentle upright folds, F3 , with NW-SE striking axial plane represent structure of third generation. Superimposition of F2 on F1 has resulted in Type 3 interference pattern and dome and basin structures are due to the interference of F2 and F3 folds. F1 and F2 folds are attributed to WNW-ESE buckling and F3 is reported to be due to shortening across it. The 'sheath folds' are due to heterogeneous simple shear aiong the axial plane of the F2 fold. The map shows a large scale southwesterly plunging overturned F2 fold. Post-exhumation deformation has resulted in brittle shearing parallel to the axial plane of F2 fold. The structure of the area points to a collisional tectonic setting like other granulite belts of Gondwanaland.
Jabalpur Earthquake of May 22, 1997: Constraint from Aftershock Study
Authors: Acharyya S. K. , Kayal J. R. , Roy A. , Chaturvedi R. K.
Published: November 2024

Macroseismic and microseismic (aftershock) investigations were carried out by the Geological Survey of India immediately after the Jabal pur earthquake (M 6.0) of May 22, 1997. The meizoseismal area of an intensity VIII (MSK) is 35 km long and 15 km wide, trending ENE-WSW. The aftershock investigation was earned out by a five-station temporary microearthquake (MEQ) network. Five felt aftershocks (M=3.0) and 23 aftershocks in the magnitude range 1.5 to < 3.0 were recorded by the network. These are mostly clustered in an elongated area, 15 ×10 krn, near the main shock epicentre. and occurred at a depth range 35-40 k.m which is compatible with that of the main shock. The fault-plane solution of the main shock and the aftershocks revealed reverse faulting with left-lateral strike-slip component The hypocentral section and the fault-plane solutions indicate that the pre-existing ENE-WSW trending Nannada South Fault is deep-rooted to mantIe depth, and has been activated at the crust-mantle boundary to produce the main shock and the aftershocks. The failure appears to be caused in response to the northward post collisional movement of the Indian plate.
Reaction Textures of Retrograde Pressure-Temperature-Deformation Paths from Granulites of Schirmacher Hills, East Antarctica
Authors: Ravikant V. , Kundu Amitava
Published: November 2024

A retrograde path inferred for the Schirmacher Hills granulites involves near ITD path following post-peak granulite facies metamorphism (M1/D1), preserved only in enclaves, followed by near IBC path, M3, post dating M2/D2 granulites facies metamorphism and deformation. Final uplift and cooling of the terrain occurred in the upper amphibolite facies metamorphic conditions, M4, syntectonic with respect to D3 deformation and emplacement of large volume of syntectonic granitoids. Fluids released during cooling and crystallization of these granitoids probably caused the large scale retrogression of granulite facies rocks to amphibolite facies gneisses.
On the Genesis of Indian Beryls
Authors: Narendra Babu K. , Sebastian Ansom
Published: November 2024

Beryl samples collected from pegmatites of Bihar, Rajasthan, Andhra Pradesh and Kerala. Showed marked correlations between chemical constituents and physical parameters. The following are the major observations of this study: (i) Specific gravity and refractive index vary with alkali elements, (ii) unit cell dimensions vary with divalent metal ions and alkali elements, (iii) Be content correlates with refractive index, unit cell dimension c and also with Li content. Beryl samples are alkali-poor and form two distinct populations with alkali concentration of 0.594-0.863 wt% and 1.468-1.871 wt%. These two chemical types of beryls possibly tally with two generations, one of primary zones and the other of late phase cleavelandite. The data also showed that the analysed beryls from Indian pegmatites contain extremely low concentrations of rare alkalies. Correlation of Al with divalent metal ions; and Be with Li signifies that both octahedral and tetrahedral substitutions can take place in these beryls. In the structural formula the sum (Al3++Me2+), in all cases, showed close proximity to 2 justifying octahedral substitution.
Stratigraphic and Sedimentologic Evolution of the Proterozoic Siliciclastics in the Southern Part of Chhattisgarh and Khariar, Central India
Authors: Datta Basudeb
Published: November 2024

The Proterozoic siliciclastic successions in the southern part of Chhattisgarh around Panduka village, Raipur dt., Madhya Pradesh and in the northern part of Khariar plateau around Nawapara, Nawapara (North Kalahandi) dt., Orissa consist of three comparable formations namely, the Lohardih, the Chaporadih and the Kansapathar Formations of the Chandarpur Group of the Chhattisgarh Supergroup. The evolution of the sedimentary successions in both the areas follows identical succession of events, i.e., an initial progradation and a subsequent transgression-regression phase. Palaeoslope of both the areas was towards south/southeast and the palaeo-shoreline trend was ENE-WSW to NNE-SSW. Marine transgression occurred from southeast. Environmental and palaeocurrent analyses suggest that the siliciclastic successions at Panduka and Khariar, separated by a wide stretch of crystallines, developed in different parts of the one and same basin, the Panduka area represents the proximal part whereas the Khariar plateau represents the distal part.
Genus Thalmannita (Foraminifera) from the Niniyur Formation (Paleocene), Ariyalur Area, South India
Authors: Malarkodi N. , Nagaraj H. M.
Published: November 2024

Thalmannita in the South Indian Paleocene, outside the West European and Tethyan biogeographic realms, is recorded for the first lime. The genus has two existing species madrugaensis and hajeezi. The following four new species are added namely, Thalmannita niniyurensis n.sp. T. adanakurchchensis n.sp., T. gowdai n.sp. and T. sastryi n.sp. The Thalmannita is a well known guide fossil of the Paleocene age.
Deformation Structures in the Subathu Rocks, Dogadda Area, Garhwal Himalaya
Authors: Agarwal K. K.
Published: November 2024

The shale-siltstone sequence of the Subathu Formation in the Dogadda area shows three main types of deformation structures, namely (i) small cleavage duplex, (ii) pencil structures, and (iii) cleavage refraction in the mesoscopic open folds. The development of these structures without a pervasive fabric and syntectonic recrystailisation of phyllosilicates could be assigned to deformation under subaerial conditions. The whole deformation pattern seems to be the result of advancement of crystalline thrust wedges over the Lesser Himalayan sedimentary rocks.
Platinum Group Elements in REE-Th-Zr-Ti-Rich Tremolite-Actinolite Rock from Vattalakki, Palghat District, Kerala
Authors: Dhana Raju R. , Vijayalakshmi S. , Mahalingam T. R. , Rao C. R. M. , Roy Madhuparna
Published: November 2024

Platinum Group Elemental (PGEs-Pt, Ir, Pd, Rh and Ru) contents, determined by ICP-MS, are reported in a rare REE-Th-Zr-Ti-rich ultrabasic tremolite-actinolite rock from Vattalakki, Kerala. Data on PGE, together with unusually high contents of REE, Th, Zr and Ti at percent level, indicate this rock as 'anomalous'.
Occurrence of Gabbro-Anorthosite Intrusive, Ramdaspeta, Anantapur District, Andhra Pradesh
Authors: Suresh G. , Srinivasan K. N. , Roopkumar D. , Rao N. V.
Published: November 2024

A linear body of gabbro-anorthosite has been recognised as a syn-to-late kinematic intrusion within the calc-alkaline granitoid suite of the Eastern Dharwar Craton, having the characteristics of layered mafic intrusion (LMI) and major oxide composition similar to massif type anorthosite.
Splenial and Vomerine Dentitions of Pycnodont Fishes from the Upper Part of the Subathu Formation (Middle Eocene), Malyuriyan, Rajauri District, Jammu and Kashmir
Authors: Thappa B. D. , Raina B. K. , Prasad G. V. R.
Published: November 2024

Intensive search for vertebrate fossils in the Eocene Subathu Formation, Kalakot, Jammu and Kashmir has resulted in the recovery of one complete vomer, two splenials (one fairly complete and one fragmentary) and a number of isolated teeth of pycnodonts, a holostean group of fishes. The vomer is the first report of its kind from the Indian subcontinent. Based on dental morphology, size and length/width proportions of the teeth on individual tooth rows, the vomer and splenials are referred to two new species of Pycnodus: P. subathuensis and P. dattai, respectively.
Geochemistry of the Metavolcanics of the Hutti-Maski Schist Belt, South India: Implications to Gold Metallogeny in the Eastern Dharwar Craton
Authors: Giritharan T. S. , Rajamani V.
Published: November 2024

The Hutti-Maski schist belt in the eastern Dharwar craton consists predominantly of mafic metavolcanics metamorphosed to amphibolite facies. The amphibolites are tholeiitic in composition with higher abundances of iron and with flat to LREE enriched rare earth patterns. Modelling of major and trace elements suggests that the tholeiitic protoliths were formed from melt enriched mantle sources by different extents of partial melting at pressures -25 kbars. The most common mafic metavolcanics in the three auriferous schist belts of eastern Dharwar craton such as the Kolar. the Ramngiri and the Hutti belts are high-iron tholeiites with LREE enriched rare earth patterns. The gold mineralization in the form of quartz-carbonate veins in the three belts is commonly hosted in high irontholeiitic protoliths. The process of formation of Fe-rich tholeiites. their metamorphism to amphibolites and their subsequent emplacement along terrane boundaries could have provided a favourable geochemical environment for gold mineralization.
A Study of Inverted Metamorphism in the Higher Himalayan Yamuna Valley, Uttarkashi District, Uttar Pradesh
Authors: Biyani A. K.
Published: November 2024

The distinctive feature of the Higher Himalaya of Yamuna Valley is that with in the hanging wall greenschist metapellitic nappe, quartzite and marble of footwall are exposed both with inverted disposition of isograds in the eyelid windows. These Barrovian type syn- to post-tectonic events of metamorphism are recorded in the rocks. Chlorite to garnet zone paragenesis in metapelitic rocks and chlorite-biotite zone paragenesis in quartzite and marble are developed by stronger earlier event of metamorphism (M1). The second event of metamorphism (M2) is mild, followed by another feeble retrogressive event (M3). While inversion of isograds in metapelites is attributed to hot slab thrust over the cold, in quartzite and marble, evidences suggest additional role of shear heating and contact effect by a sub-surface cooling igneous body.
Trace Fossils from the Cambrian of Zanskar (Ladakh Himalaya) and their Stratigraphic Significance
Authors: Parcha S. K.
Published: November 2024

The Cambrian sequences exposed in the Kurgiakh Valley of the Zanskar area of Ladakh Himalaya contain a variety of trace fossils as in other Tethyan sequences of Himalayan region. The Ichnogenera identified from this sequence belongs mostly to the traces of trilobite origin, with other traces of arthropod and of unknown origin. These include the Ichnogeneras such as Rusophycus ; Cruziana; Monomorphichnus; Phycodes; Planolites; Skolithos; Meandering trails and trilobite scratch marks. The traces mostly belong to Early Cambrian to early Middle Cambrian in age and occur below the trilobite assemblage; few traces extend above the trilobite-bearing beds. The described species have been collected from the Kurgiakh Formation. The first appearance of species of Phycodes pedum has a special bearing on the identification of the beginning of Cambrian in the sequence. The present report of trace fossils from this Formation is the first report of trace fossils from this area of Ladakh Himalayan region.
Open System Fractional Crystallization Process in the Evolution of Deccan Basalts of Pratapgarh Region, Western India
Authors: Pandit M. K. , Srivastava R. K.
Published: November 2024

The northwestern fringe of the Deccan Flood Basalt sequence is characterized by isolated occurrences of sub-horizontal tholeiitic flows. Because the flow units in this region are not traceable over large distances, the petrographic and geochemical characters have been utilized to establish nine flow units of olivine tholeiite (OT), quartz tholeiite (QT) and low calcium quartz tholeiite (LCT). The flows show striking mineralogical and chemical similarity. Low-Mg numbers and moderate to high silica content indicate the derivative nature of the magma. The flow sequence has evolved through predominant plagioclase fractionation and less significant clinopyroxene separation from a non-primary olivine tholeiite melt from which olivine had been removed earlier. Cyclic variation in geochemical signatures and prominent chemical breaks within the flow sequence indicate a periodically replenished, open system, shallow level magma chamber with gabbroic fractionation.
Fluid Inclusion Characteristics of Tin Bearing Pegmatites of Malkangiri District, Orissa
Authors: Pal D. C. , Panigrahi M. K. , Mishra B.
Published: November 2024

Stanniferous pegmatites of Malkangiri occur both in metabasics and metasediments showing signatures of deformation but very little wall rock alteration. Fluid inclusion microthermometric studies in pegmatitic quartz and quartz from quartz veins reveal the following three types of inclusions: aqueous biphase, metastable (?) monophase aqueous inclusions which do not show any thermal response, and rare halite-bearing inclusions. The CO2-free nature of the inclusions is noteworthy. Isochores of halitebearing inclusions (where Ts Nacl > Th) intersect at P-T values of 2.65 kb and 337°C, implying preservation of the magmatic fluid that separated during the late stage of felsic magmatism in the area. Additionally, the above P-T values compare reasonably well with those obtained from the intersection of halite liquidi with the corresponding isochores.

Tin-bearing pegmatites in metabasics are characterized by their low temperature of homogenization and isothermal variation in salinity. This is explained by mixing of a Sn-bearing, granite affiliated, presumably reduced fluid with a heated, less evolved oxygenated meteoric water that led to cassiterite precipitation. Interestingly, inclusions in cassiterite-bearing pegmatites within metasediments record a low temperature comparable with those from within metabasics. In contrast, barren pegmatites within the schistose metasediments preserve high temperature signature and indicate a simple cooling trend. The study reveals different styles of evolution of stanniferous and barren pegmatites at Malkangiri.
Occurrence and Origin of Water Well Methane Gas in Bangladesh
Authors: Ahmed K. M. , Hoque M. , Hasan M. K. , Ravenscroft P. , Chowdhury L. R.
Published: November 2024

Gas occurrences in irrigation wells have been reported from most parts of the country, and in some parts of the southeast region, gas occurrences have become a limiting factor for groundwater development. Methane is the main component of water well gases and is readily identified by its ignition characteristics. It has been found that conditions required for gas formation, such as the amount of total organic carbon and organic matter, depth of burial, hydrothermal gradient and degree of compaction, are all favourable for the generation of biogenic gases in the deltaic regions of the Bengal Basin. Biogenic gas from water wells contains only methane as the hydrocarbon gas and along with more than one per cent (by volume) of carbon dioxide. On the other hand thermogenic gas from deep wells contains methane and other higher hydrocarbon gases along with less than one per cent of carbon dioxide. Areas marked by high groundwater salinity generates more methane than other parts of the country and this is suggestive of estuarine environment of deposition of the aquifer materials in those areas.
Occurrence of Palladian Melonite in Jaduguda Uranium Deposit, Singhbhum Shear Zone, Bihar
Authors: Narasimhan D. , Sunilkumar T. S. , Babu E. V. S. S. K. , Krishna Rao N.
Published: November 2024

Palladian melonite, containing upto 7% palladium is reported for the first time from the uranium ores, Jaduguda Mines.
The Lead Isotope Geochemistry and the Uranium-Lead Apparent Ages of the Sandstone - Type Uraniferous Ore of Domiasiat, Meghalaya, India
Authors: Das Radha R. , Dwivedy K. K. , Mahalingam T. R. , Mathews C. K.
Published: November 2024

The relative abundance of radiogenic lead varies depending on the mineralogical characteristics of the ore. In high uranium containing coaly matter, radiogenic lead is > 80% of the total, whereas in a composite ore, as much as 60% of the total is of the initial common lead. The uranium-lead 'apparent ages' are in the range of 25 Ma to 95 Ma and are related to the mineralogical assemblage in the ore. The most recent of the uranium mineralization, of 'apparent age'-25Ma is with the coaly matter separates that contain considerable amount of pyrite. The variations in the abundance and distribution of radiogenic lead isotopes and the resultant orderly changes in 'apparent ages' of uranium mineralizations in different type of mineral separates are attributed to the existing favourable conditions in the ore for movement of uranium from the rock and preferential concentration and retention in the coaly matter, leading to more than one stage uranium mineralization.
A Prognostic Assessment of the Environmental Impact due to Open Cast Mechanised Mining of the East Coast Bauxite Deposits in Andhra Pradesh
Authors: Ramam P. K.
Published: November 2024

The East Coast Bauxite (ECB) Province of India, extending into the neighbouring States of Andhra Pradesh and Orissa, has contributed to a substantial rise in the total bauxite resource of the Indian sub-continent. Bauxite is gibbsitic and in situ. Thickness of the bauxite profiles varies from 3 to 54 m and bauxite is confined to select geomorphic expressions viz., sloping, landforms, and are amenable to open cast mechanised mining.

There are chances of accelerated recharge of the groundwater table, through coursed run-off, of the meteoric precipitation in the mining areas. In fact, tiny reservoirs of surface water can be created in the mined out areas. There is no possibility of toxicity due to Al as it is insoluble. Other toxic elements like Cr, Mn, V etc. are in negligible amounts to impart toxicity to the water regime. Human settlements in the area are sparsely populated and widely scattered. It is logical to expect employment opportunities to some of the inhabitants. Infrastructural facilities created to facilitate mining and movement of are, would contribute to improved socia-economic conditions and a rise in the per capita income.

Extensive green belt development and other mitigative measures, being practiced as a part of Environmental Management at Panchpatmali bauxite mine in Orissa is a case study to demonstrate that it is possible to maintain the eco-system of the terrain even during the mining phase. The bauxite deposits in Andhra Pradesh can be mined without causing any adverse impact on the prevailing environment.
A Petrochemical Study of the Proterozoic Alkaline Complex of Uppalapadu, Prakasam Province, Andhra Pradesh, India
Authors: Krishna Reddy K. , Ratnakar J. , Leelanandam C.
Published: November 2024

The Proterozoic Uppalapadu alkaIine complex (1348±41 Ma) in the Prakasam province of Andhra Pradesh is predominantly composed of nepheline syenite, hornblende syenite and quartz syenite, all of which represent an alkaline series. The pluton is closely associated with tholeiitic gabbro and ferrosyenite representing a sub-alkaline series. Geochemical characters suggest that the rocks of the alkaline series were formed by the differentiation of the hydrous alkaline basaltic magma under high PH2O, whereas those of the sub-alkaline series were formed by differentiation of an anhydrous olivine tholeiitic magma under low fO2 (reducing) conditions. Quartz syenite (an offshoot in the alkaline series) is formed either by fractionation of K-feldspar, ferrohastingsite and/or biotite under high PH2O conditions or by crustal contamination of critically saturated syenitic liquids.
Facies, Petrology and Depositional Environment of the Tertiary Sedimentary Rocks, Around Port Blair, South Andaman
Authors: Bandopadhyay P. C. , Ghosh M.
Published: November 2024

The Tertiary sedimentary rocks around Port Blair, South Andaman are classified into several facies and constraints on their formational environments are established.

The Oceanic Pelagic Sediments ( OPS ) are made up of bedded chert and variegated shale facies. Radiolarian tests and microcrystalline quartz are major constituents of the chert. The variable mixture of silt-size quartz, feldspar, clay minerals, pyroclacstic fragments and outosized terrigenous clasts constitute the variegated shale. The OPS were formed in continental-margin orogenic basin through suspension settling and fine grained sandy debris flow in deep water.

Paraconglomerate, tuff and mudstone constitute three major facies of the Mithakhari Group. Pebble size subrounded to rounded, disorganised and polylithologic clasts, in matrix support characterize the conglomerate facies. Pyroclastic facies are coarse grained and unstratified tuff and fine grained and well stratified tuff. They are crystal-rich tuffs of basic to intermediate composition. Massive mudstones interbedded with conglomerate and tuff are geochemically similar to sedimentary mudrocks. Conglomerates represent debris flow deposit formed in submarine channel. The tuffs are interpreted as pyroclastic debris flow deposit and primary air-fall ash turbidites. Mudstones indicate deposition of pelagic mud from basinal water.

The Andaman Flysch comprises quartzwacke sandstone and dark shale facies. Bouma sequences are conspicuous in sandstone-shale rhythmites. Angular and assorted detrital grains that constitute the framework components and also contributed to the formation of matrix, exhibit diffuse and corroded grain outlines and other textures indicative of burial diagenesis. The Andaman Aysch is interpreted as proximal turbidites formed in mid-fan environment by a combination of sandy debris flow deposition and pelagic sedimentation adjacent to an uplifted source terrane.
Depositional Environments: Inferred from Grain Size Along the Coast of Tamil Nadu
Authors: Mohan P. M. , Victor Rajamanickam G.
Published: November 2024

Between north of Pondicherry and Ennore (12°03' to 13°12' N - 79° 53' to 80° 15' E) two geomorphic units such as beach and beach ridges and their associated units (Low Water Mark (LWM). Foreshore (FS). Berm (BM). Backshore (BS), Dune (DU) and Beach Ridge (SL) are selected for the present study to understand the micro level variation in the depositional environment. The samples mostly show medium to fine size, well sorted to moderately sorted, very coarse skewed to fine skewed and platykurtic to leptokurtic nature. Graphic mean, standard deviation, skewness and kurtosis confirm that the sediments are of typical beach origin. Frequency curves indicate that the dune samples represent unimodal and others show bimodal to poly modal source of influence. Based on bivariant plots the samples of dune, berm, backshore, foreshore and low water mark with strandline deposits are classified.