bluuebunny/crossref_metadata_2025 huggingface dataset:
Polyphase Folding Deformation in the Hutti-Maski Schist Belt, Karnataka
Authors: Roy Abhinaba
Published: November 2024

Three phases of folding deformation (F1, F2 & F3) are recognised in the Hutti-Maski schist belt. The first two phases (F1 and F2) are quite pronounced producing regional folds whereas the last one (F3) is of mild intensity. F1 folding is accompanied by the development of schistosity (S1) in metabasalt and metasedimentaries, mylonite banding (Sd) in gold quartz veins and minor folds on bedding plane (So) and vein quartz. Two major F1 folds, viz., a syncline and an anticline could be traced in the area on the basis of orientation of pillow structure in metabasalt. Gold mineralisation in Hutti-Maski schist belt is mainly controlled by first phase of folding (F1) and associated regional metamorphism. F2 fold shows clear evidence of superposition on F1. F1 axial trace is folded by F2 folds. F2 folding is accompanied by the development of crenulation or slip cleavage (S2), minor folds on S1 and Sd and shear fractures and faults. F2 fold is represented by two major folds, viz., an antiform and a synform having axial traces along NNW-SSE to NW-SE direction and plunge around 45° to 50° towards Nw to NNW. A time gap between F1 and F2 is marked by the intrusion of a granodiorite body. F3 is developed on the limbs of F2 folds, and is accompanied by the development of S3 cleavage and kink band or chevron folds. Axial plane of F3 fold trends N75°E-S75°W (approx.) with vertical dip. Fold axis (F3) shows very steep westerly plunge.
Copper Mineralization in Padar-ki-Pal, Dungarpur District, Rajasthan
Authors: Degaonkar Satish , Panchapakesan V. C. , Sahu K. C.
Published: November 2024

Copper mineralization in Padar-ki-pal is localised along a N25°E striking phyllite-quartzite contact, transected by three sets of steeply dipping joint planes. Mineralization is in the form of veins, disseminations and permeations of chalcopyrite and other related sulphides. Textures and other related structures reveal the replacement nature of the deposit. Fluid inclusions indicate an aqueous transport of ore elements by a brine undersaturated with respect to highly soluble salts which boiled off at least at the end stage of mineralization. The filling temperature of the inclusions showed signs of entrapment of a homogeneous liquid solution, ranging from 200° to 270°C.
Freshwater Xenacanthid (=Pleuracanth) Shark Fossils from the Upper Triassic Maleri Formation, India
Authors: Jain S. L.
Published: November 2024

Xenacanth (=pleuracanth) shark fossils are exclusively known from the freshwater deposits from late Devonian up to the Upper Triassic. Triassic occurrences are sporadic and have so far not been supported by skull material. Teeth and skull material from the Upper Triassic Maleri Formation consists of well preserved characteristic' Diplodus' type teeth and a few calcified cartilages of the skull region. It shows affinity with the Australian X. parvidens from the Lower Wianamatta Series of New South Wales and X. moorei from the Keuper of Somersetshire (England) and Wurtemberg (Germany). Being the first record from India, the material is assigned to X. indicus sp. nov. The three species viz., X. parvidens, X. moorei and X. indicus represent the last survivors of the family Xenacanthidae in the Upper Triassic.
Application of Aerial Photographs and Landsat Imagery for Geological Mapping Around Chandrapur (Maharashtra)
Authors: Subbarao B. V. , Alasingrachar M. A. , Shah S. D.
Published: November 2024

Linear quartzite ridges were established in the NE part of the imagery, from the aerial photointerpretation and later ground check. The extreme eastern part of the imagery has distinct evidences of faulting within the folded strata. Other structural features such as fault planes and doubly plunging synclinal features are also established. Three major formations such as granites, quartzites, and granite gneisses and schists could be delineated on the photogeological map along with the dolerite dykes of later origin. Numerous water bodies with N-S and NNW-SSE alignment are suggestive of the presence of hidden basement faults. Also the Wainganga river's older courses could be clearly marked, besides establishing the structurally controlled flow of Penganga, Wardha and Wainganga rivers. Dissimilar rock units are differentiated from the interpretation of colour composites.
Discovery of Late Palaeozoic Brachiopod in the Upper Krol of the Nainital Hills, Kumaun Himalaya
Authors: Valdiya K. S.
Published: November 2024

Discovery of Linoproductus sp. in the upper part of the Upper Krol Limestone near Nainital indicates Upper Palaeozoic, probably late Carboniferous or Early Permian age not only of the lithostratigraphic unit, but also of the assemblage of stromatolites having distinctive morphology and restricted vertical distribution.
Lamprophyres from Indian Gondwanas - K-Ar Ages and Chemistry
Authors: Sarkar Amitabha , Paul D. K. , Balasubrahmanyan M. N. , Sengupta N. R.
Published: November 2024

Lamprophyric dyke rocks occurring in the Indian Gondwanas (Permian-Lower Cretaceous) form a consanguinous suite ranging from ultrabasic mica-peridotite to micro-syenitic assemblages. Chemical characters include low SiO2 (ca. 40% or less), high (FeO+MgO) and high MgO/FeO and K2O/Na2O ratios. The petrographic and chemical characters have been discussed in a broad framework after Rock (1977). K-Ar radiometric ages on four biotite separates and one whole rock from three different localities range from 105 to 121 Ma and are believed to represent true crystallisation ages.
On the Phase Transformation of Bauxite Phutkapahar Bauxite Deposit, Madhya Pradesh, India
Authors: Ghosh K. P.
Published: November 2024

Optical, X-ray, D.T.A. and Scanning Electron Microscopic studies on the gibbsitic bauxite samples of Phutkapahar bauxite deposits, Madhya Pradesh are presented. Natural gibbsite changes to boehmite -----? ? A1203 --- --? a A1203 in response to variable thermal kinetics. The transformation is topotactic, diffusion controlled and is largely defined by both homogeneous and inhomogeneous mechanisms of dehydration.
Electron Microscopic Studies of Clay Minerals from Three Bauxite Profiles
Authors: Balasubramaniam K. S. , Paropkari A. L. , Nagarajan R.
Published: November 2024

Laboratory studies of three bauxitic profiles from Maharashtra and Tamil Nadu suggest that plagioclase feldspar alters to gibbsite via halloysite and not from kaolinite. The alteration characteristics of feldspars and the morphological aspects of clays leading to the genesis of bauxites were studied under electron microscope.
Petrological Study of Ghuneri Lignito-Bituminous Coal, District Kutch, Gujarat, Western India
Authors: Pareek H. S.
Published: November 2024

The Umia Beds (Wealden) exposing a seam of Iignito-bituminous coal 75 cm in thickness near Ghuneri in Kutch, is of Cretaceous age. The coal is high in moisture (8.09-12.15%), ash (11.61-23.81 %), and sulphur (1.91-3.04%) contents, and is lustrous, banded and vitrain-rich. It is composed dominantly of collinite, and commonly of telinite, showing microstructural details of the secondary wood palmoxylon (?) flora. Fusinite is common and shows cell lumen occupied by carbonized resins or a dark coaly matter possibly bituminite. Fusinized resins occur as traces and are similar to those in the Gondwana coals. Fungal sclerotia is recorded and is similar to that in the Tertiary lignites.

The coal is distinct and different from the Gondwana coals or Tertiary lignites, but shows greater resemblance in petrological characters to the Permian coals of Damodar Valley.
Stratigraphy and Structure of the Precambrian Banded Iron Formation and Chromite-Bearing Ultramafic Rocks of Sukinda Valley, Orissa
Authors: Chakraborty K. L. , Chakraborty T. L. , Majumder Tapan
Published: November 2024

The Sukinda Valley of Orissa is underlain by the banded iron formation (BlF) and chromite-bearing ultramafic rocks of Precambrian age. Besides these, local exposure of a quartz-arenite bed with basal conglomerate is correlated with the Kolhans. A basal quartzite horizon is conformably overlain by the BIF. lhe quartz-arenite (Kolhans?) with a conglomerate at the base lies with a local disconformity over the BIF. Chromitebearing ultramafites are pre-kinematic intrusives into the iron formation and have been co-folded with the older sediments. Orthopyroxenite and granitic rocks are intrusive into the chromiferous ultramafites. Occasional intrusive dolerite dykes in the valley may be correlated with the Newer Dolerites of Singhbhum.

The regional structure of the Precambrian rocks of the Sukinda Valley, as established by the present authors, is a cross-folded doubly plunging syncline with the culminated fold axis striking ENE-WSW which is parallel to the main fold axis of the Eastern Ghats Orogenic belt. The plunge of the main fold axis is towards NE and wsw. The cross-folded axis, lying between Tungaisuni and Champajhar villages, trends NNW-SSE and is subparallel to the cross-folded axes of the Eastern Ghat Orogenic belt.
Gondwana Type of formation with Phosphatic Rocks in S.E. Nepal
Authors: Bashyal R. P.
Published: November 2024

A new Formation called the Barahakshetra Formation is recognised in Southeastern Nepal. It is separated from the Siwaliks (Tertiary) to the south by the MBT and has a tectonic contact with the Sanguri Formation (Lower Palaeozoic ?) and the Metamorphic Series (Precambrian ?) to the north.

The basal part of the Formation is marine with radiolaria, glauconite and with a penecontemporaneous trachyte-keratophyre volcanism. A glacio-marine episode is represented by the pebbly shales in the eastern part of the basin. The continental character and the regressive nature of the upper part of the Formation is indicated by the detrital materials with coal and plant fossils. The sediments were deposited in a epicontinental basin of paralic type. Littoral zones (intertidal-supratidal) are indicated by many sedimentary features.

The volcanic sandstones and the conglomerates of the region are feebly phosphatic. The Barahakshetra Formation is compared with corresponding units of the Gondwana Formations of the Himalaya. It is noticed that lithostratigraphically the Barahakshetra Formation is similar to that of Darjeeling-Sikkim area. The Gondwana affinity is confirmed by the presence of plant fossils. The geological significance of this Formation is discussed.
Middle Eocene Benthonic Foraminifera from the Vinjhan-Miani Area, Kutch-Palaeoecological Significance
Authors: Jauhari A. K.
Published: November 2024

An attempt has been made to discuss the palaeoecologic significance of the foraminiferal assemblage recorded from the Middle Eocene rocks exposed around the villages Vinjhan and Miani. The interpretation leads to the conclusion that the Middle Eocene rocks were deposited in inner-to mid-neritic environment characterized by warm water conditions.
Redlichid Fauna from the Cambrian of Kashmir
Authors: Shah S. K. , Raina B. K. , Razdan M. L.
Published: November 2024

The redlichid fauna from the Lower Cambrian of northwestern Kashmir is described. In addition to Redlichia noetlingi (Redlich), it includes R. cf. knjazevi Repina and Tungllsella obesa Repina, not recorded from India so far. Inarticulate brachiopods, Botsfordia granulata (Redlich) and? Neobolus are also described from the same zone. The fauna corresponds to Botomian and represents upper middle part of Lower Cambrian.
Geology and Geochemistry of Paragneisses from the Javanahalli Schist Belt, Karnataka, India
Authors: Naqvi S. M. , Narayana B. L. , Rama Rao P. , Ahmad S. M. , Uday Raj B.
Published: November 2024

The lowermost member of the Javanahalli schist belt consists of meta-arkoses/ paragneisses with interbedded epidote-quartzite and calc-silicate bands. These meta-arkoses exhibit relict current-bedding, arkosic texture and grain-to-grain variation in anorthite content within the same sample. Plagioclase is subordinate to K-feldspar and is relatively more weathered and sericitized. Orthoclase predominates over microcline in the total K-feldspar content and the quartz/feldspar ratio is generally very low. The meta-arkoses appear to be first-cycle sediments.

The composition of these paragneisses is unusual for Archaean metasediments. They are enriched in K, Si, Fe, Mg, Th, Rb, Ni, Cr and Co and depleted in Na, AI, Sr and often in Ca. The meta-arkoses of Javanahalli schist belt may be the product of strong and/or rapid chemical disintegration of Archaean tonalitic gneisses and basic and ultrabasic rocks. all of which were prominent components of the continental crust at the time the Javanahalli belt formed. If the meta-arkoses have not undergone major metasomatism, then their high abundance of K and Rb may indicate intense chemical leaching of these tonalitic source areas. Most of the saIt of the primitive oceans might have been derived from this intense leaching of the ancient cratonic tonalite gneisses.
A Tectono-Stratigraphic Model of the Chitradurga Schist Belt, Karnataka, India
Authors: Mukhopadhyay Dhruba , Baral Mohan Chand , Ghosh Debashish
Published: November 2024

The regional structure within the Chitradurga schist belt consists of a central antiform flanked by two synclines on either side. The central antiform is a second generation struc:ture which has refolded an earlier syncline whose axial trace is now exposed on either side of the central antiform. The second generation antiform shows regional plunge culminations and depressions along its axis. The earlier syncline had originally curved fold axis and was a canoe shaped fold. In the southern part of the schist belt a tectonic slide has cut off the lower limb of the early syncline. This came into existence before the second phase of folding. The stratigraphic sequence within the schist belt has been worked out taking into account this structural framework.
Heavy Minerals in the Sediments on the Outer Continental Shelf between Vengurla and Mangalore on the West Coast of India
Authors: Kidwai R. M. , Nair R. R. , Hashimi N. H.
Published: November 2024

Fifty-eight sediment samples from the outer continental shelf between Vengurla and Mangalore were analysed for heavy mineral content. The heavy minerals consist of principally opaques, hornblende, epidote, garnet, sillimanite, hypersthene and zircon, with minor amounts of andalusite, augite, kyanite, monazite, muscovite and tremolite-actinolite. This mineral assemblage and the distribution pattern define four heavy mineral provinces on the continental shelf from Vengurla to Mangalore. Further, the mineral assemblage suggests derivation from mixed metamorphic and igneous terrain with a predominant contribution from metamorphic rocks.
The Structural Set up of Apart of the Malangtoli Iron Ore Deposit, Orissa
Authors: Chatterjee A. K. , Mukherji P.
Published: November 2024

The paper describes the localisation of iron ore bodies in the Malangtoli group forming the southeastern end of the Bonai Synclinorium comprising Singhbhum-Keonjhar-Sundergarh group of iron formations. Three fold systems affect the area. Barring a few instances which are due to facies changes, the overall pattern of Occurrence of iron ore bodies is fairly conformable with the tectonic set up and the behaviour of such ore bodies are continuous with the structural pattern. The distribution of iron ore body/bodies in space is/are controlled by the superposed fold systems, the ore body reaching maximum depths in structural basins and/or canoes and minimum depths (occasionally base rock outcropping) in structural highs, i.e., domes and inverted canoes. Certain conclusions arising out of this are analysed.
Polyphase Deformation of Ajabgarh Stage Rocks, Delhi Group, Around Narnaul, Mohindergarh District, Haryana, India
Authors: Bhola Anand Mohan , Varadarajan S.
Published: November 2024

A detailed study and analysis of all the planar and linear elements in the lithic units of the area, in both meso and macro scale reveal that they bear the impress of three phases of folding, F1 F2 and F3. The most dominant phase is the second phase resulting in open asymmetric folding with high wave length/amplitude which express in mesoscale crenulations on the planar surface of F1 folding. The F1 phase is responsible for the regional foliation S1 which is parallel to lithic banding S0. The tight isoclinal folds develop appressed surface which act as form-surface of F2. The F1 and F2 are generally co-axial. The last phase of folding F3appear as broad open cross-folds broadly warping the pre-existing foliation. This phase can distinctly be observed on map scale.

Distinction between each phase and the associated structures is based on the overprinting relations, in particular the bending of axial surface foliation and other interference patterns between the existing phases. Structural analysis of the area indicates operation of a predominantly sub-horizontal NW-SE oriented stress.
Grain Size Variation in the Sediments off Tuticorin Harbour, Tamil Nadu
Authors: Venkatesh K. V. , Ray I.
Published: November 2024

The size parameters of the near shore sediments off Tuticorin vary as follows: inclusive graphic mean from 1.41 to 2.22 phi; standard deviation 0.58 to 0.91 phi; skewness - .07 to - .37 and kurtosis 0.91 to 1.15. Decrease in the values of mean size towards southwest indicates the movement of sand in that direction which is largely aided by the wind induced currents. A close correlation between mean grain size and sorting is mferred. Sporadic occurrences of coarser sand nestled by finer ones noticed closer to the site of break-waters speaks of the low transporting ability of the back wash. The important mode of transport is through saltation and traction.
Manganese Silicate-Carbonate Protore (Queluzite) from the Srikakulam Manganese Belt, Andhra Pradesh
Authors: Krishna Rao S. V. G. , Bhattacharyya Samit , Sarma K. J.
Published: November 2024

Manganese silicate-carbonate protore (queluzite) and a rare manganese olivine (knebelite) are being reported for the first time from India. The protore is comparable to the 'Queluzite Type' and occurs as conformable bands in close association with manganese ore body as well as different members of the Khondalite Group of rocks. So far, the knebelite is reported to occur in association with other manganese minerals, particularly in iron-manganese ore deposits and their associated skarns. It is surmised that the protore represents metamorphic equivalent of carbonate-silica-bearing manganiferous sediments.
The Deoban Structural Belt of the Garhwal Himalaya
Authors: Ganesan T. M. , Verma R. N.
Published: November 2024

The Deoban structural belt is a WNW-ESE trending autochthonous belt and exposes some of the oldest sediments of the Lesser Himalaya. The Deoban Group represents a thick pile of carbonate sequence of Riphean age deposited in a stable shelf environment. It is succeeded by the geosynclinal sequence' of the Simla Group in the central and southern parts of the basin. In the northern part it is succeeded paraconformably by eugeosynclinal sediments of the Jaunsar Group comprising argillaceous and argillocalcareous rocks with associated volcanics and lenticular conglomerate and boulder bed at places. The Jaunsar Group is welded to its basement in the northern part, while in the south it rides over the Simle Group (some times the Deoban) which is now marked by the Tons thrust. The Pharat and Bidalna windows expose the Simla Group rocks beneath tbe Chandpur Formation of the Jaunsar Group in a tectonic window of the Krol superficial nappe over the Simla Group

The Shali and the Barahat-Pithoragarh structural belts are the continuation of the Deoban structural belt in the west and east respectively, beneath the veneer of the Jaunsar or the Jaunsar-Jutogh thrust sheets.
Geochemistry of the Precambrian Magmatic Rocks of Mayurbhanj District, Orissa
Authors: Iyengar S. V. P. , Kresten P. , Paul D. K. , Brunfelt A. O.
Published: November 2024

In the Mayurbhanj area, Orissa, Badampahar group of rocks formed the cratonic block for younger Dhanjori Group. From the composition of the chilled facies of the gabbro-anorthosite, the parent magma is believed to be low in potash and alumina. The chondrite normalised REE pattern of the ultrabasic rock of Badampahar Group is unfractionated. In contrast, the gabbro-anorthosites have fractionated REE pattern with Eu anomaly. The degree of fractionation increases in the granite-granophyres. Th/U ratios systematically increase with the total REE content. It is suggested that the source region of the magmatic rocks is anomalous in respect of the large ion lithophile elements.
Petrophysical Studies on Metabasics of the Sanko-Kargil Area, Kashmir Himalaya
Authors: Gogte B. S. , Sarma K. V. L. N. S. , Ramana Y. V.
Published: November 2024

Petrologically, the metabasites comprise of metavolcanics (metabasalt, spilitic basalt, metadolerite, spilitic diabase and trachybasalt), green schists, amphibolites and meta-greywackes, and of these the meta volcanics are the most predominant. The physical properties of these rocks are: density (2.77-3.00 g cm-3), porosity (0.2-1.9%), compressional velocity (5-7 km sec-1), shear velocity (3-4km sec-1), P-anisotropy (up to 7.6%), compressive strength (700-2800kg cm-2), tensile strength (70-190 kg cm-2), Young's modulus (6.5-11.5 × 10-11 dynes cm-2), and Poisson's ratio (0.14-0.29). These variations in the physical parameters are due to (i) Metamorphic effects (low to moderate P and T conditions, green schist-amphibolite facies), (ii) The serpentinization of the phenocryst minerals, (iii) The glassy nature of the groundmass, and (iv) The differences in the groundmass/phenocryst ratios.

In general, the physical parameters of these crustal rocks from the Himalayas are higher than those of Deccan basalts even at ambient conditions. This is due to (i) Differences in their mineralogical characters, and (ii) The mode of their occurrence, the former being associated with highly folded, disturbed and tectonically affected eugeosynclinal zones, whereas the latter are of the fissure eruption type, relatively free from metamorphic effects and large scale tectonic activity.
Statistical Analysis of the Minor Fold Axes in a Part of Dudhatoli Synform Around Thalisain, Garhwal Himalaya, U. P
Authors: Khanduri H. C. , Srivastava R. K. , Dave V. K. S.
Published: November 2024

Within the Dudhatoli Group in the southern limb of Dudhatoli synform four mappable units have been recognised viz., the Dudhatoli granitoids, Dudhatoli schist, Flaggy quartzite and the Manila phyllite. In the area under study two generations of minor folds are recognised. Statistical analysis of minor fold axes has been carried out. It is concluded that the axes of two fold generations are not randomly distributed, they have different mean plunge direction with 2 and 196 degree of freedom. The folds of first generation (F1 have little or poor clustering while folds of second generation (F2) have close clustering. It is also envisaged that F1 and F2 folds have been formed under different tectonic environment.
Superposed Rivers Flowing Along Older Structures
Authors: Subramanyan V.
Published: November 2024

Superposed river-valleys have all along been generally classified as transverse valleys in geomorphic literature. A study of some unquestionably superposed rivervalleys reveals that this transverse relation to the exhumed geological structure is not always necessary. How a river-valley, which originates on a covermass, gets superposed on the older rocks, after cutting through the former, will depend on the orientation of the exhumed features vis-a-vis the river-valley that is getting superposed on them. If the superposition takes place onto ancient valleys that are themselves structure controlled, the superposed river-valleys will then be aligned along these older structures and not transverse to them. A few such significant cases are discussed.
Neospathodus Praekummeli-A New Species of Conodont from Lower Triassic of Spiti
Authors: Bhatt D. K. , Joshi V. K. , Arora R. K.
Published: November 2024

The paper describes a new species of the conodont form-genus Neospathodus Mosher, under the specific name N. praekummeli sp. nov. The presently recorded new species has a close morphologic and biostratigraphic relation with the well-known Dienerian guide-species N. kummeli Sweet.

In the Lower Triassic sequence of Spiti the first appearance of N. praekummeli sp. nov. marks the base of Ophiceras bed. It is likely that N. kummeli Sweet has evolved from N. praekummeli sp. nov. near the base of Ophiceras bed.
Sulphur Isotope Abundance Variations in Sulphides of the Dharwar Craton-Part III: Hutti
Authors: Menon A. G. , Venkatasubramanian V. S. , Vasudev V. N. , Ananta Iyer G. V.
Published: November 2024

The d34S values of pyrrhotite and arsenopyrite samples from the gold bearing quartz-sulphide reefs of Hutti have been measured. A narrow range of mantle-meteoritic values is observed indicating a magmatic-hydrothermal origin of the ores. An attempt is made to evaluate the solution parameters by the Ohmoto procedure, as outlined in Parts I and II.
Petrochemical Studies of the Lansdowne Granite Gneiss, Lesser Himalaya, India
Authors: Elsdon R. , Gupta L. N.
Published: November 2024

Petrochemical studies on fourteen representative samples of the Lansdowne Granite Gneiss indicate close compositional uniformity. Most of the analyses fall within the field of granodiorite, and lie close to the low-pressure ternary minimum in the system Qz-Or-Ab-H2O. Inter-element relationships indicate an initial magmatic origin, with pronounced gneissosity due to later deformation.
On the Depositional Environment of the Nagthat Quartzite, Lesser Himalaya
Authors: Singh Indra Bir
Published: November 2024

Nagthat quartzite shows well-developed sequences of a shallow tidal sea, and represents deposits of coastal sand bar/shoal complex and mixed flats. The sand bar deposits show large-scale cross-bedding of bar type, mega-ripple bedding and abundant planes of discontinuity. The mixed flat deposits show lenticular and flaser bedding, wavy bedding, tidal bedding, small ripple bedding, parallel bedding and laminated mud. Ripples showing characteristics of shallow-water and falling water-level environments are commonly present. In a typical Nagthat quartzite, sand bar deposits and mixed flat deposits alternate with each other in a cyclic manner. The Nagthat quartzite denotes deposit of a stable shelf association.
Occurrence of Paired-Metamorphic Belts in the Himalaya
Authors: Virdi N. S.
Published: November 2024

The Indus Suture Zone in Eastern Ladakh shows two metamorphic belts, a northern low pressure belt and the southern high pressure belt. The two belts to be referred to as Pongong and Zildat-Sumdo metamorphic belts respectively are now separated by the Ladakh batholith and post-batholith Indus flyschoidal sediments. Postmetamorphic thrusting has narrowed the width of the two belts though they can be traced for over 100km in the Indian territory before they extend into Tibet. The Pongong belt shows andalusite-kyanite-sillimanite type metamorphism accompanied by andesitic and rhyolitic volcanism and granitic activity. The Zildat-Sumdo belt is characterized by glaucophanitic metamorphism accompanied by abundant basites and ultra-basites. The two belts do not differ much in age though the high-pressure belt may be slightly younger. They have developed due to subduction and accompanying regional metamorphism.
Induced Polarisation Surveys for Sulphide Bearing Gold Lodes in the Kolar Gold Field, Kolar District, Karnataka
Authors: Menon A. K. , Bose R. N.
Published: November 2024

Induced Polarisation (Time Domain) surveys were carried out in different blocks of the Kolar Gold Fields for the delineation of sulphide bearing auriferous lodes. In the Mysore Mine area (McTaggart and Edgar Shaft area) three zones of I. P. anomaly were outlined with chargeability highs of the order of 10 to 20 milliseconds with a corresponding fall in the apparent resistivity values by about 100 ohm-metres, Exploratory trenches over the eastern anomaly zone exposed the mineralised band which helped in fixing borchole locations. A strike length of about 250 metres bctween Mysore Mine magazine and the black rock dumps has proved to be interesting as a possible economic potential zone for gold.
Incompatible Trace Element Geochemistry of Archaean Metavolcanic Rocks from the Bababudan Volcanic-Sedimentary Belt, Karnataka
Authors: Bhaskar Rao Y. J. , Drury S. A.
Published: November 2024

Data on the incompatible trace elements Ti, Rb, Sr, Ba, Zr, Nb, Y, rare-earth elements, Sc, Hf, Ta and Th are presented for basalts, andesites and rhyodacites from the Archaean Bababudan greenstone belt. All samples are genetically related and show general calc-alkaline affinities. The parent magma is proposed to have been formed by about 15 per cent partial melting of mantle at shallow depths. The source mantle is shown to have been enriched in light REE and Zr relative to primitive mantle with 2-3 times chondritic abundances. The parent magma evolved by progressive fractionation of, first olivine and pyroxene to produce incompatible element-enriched alld Cr, Ni and Co depleted tholeiites, which were then accompanied by plagioclase feldspar and possibly magnetite to generate the andesites and rhyodacites. Standard tectonic characterization parameters do not give consistent results for this suite, and until more is known about overall structure, stratigraphy and relative ages within the South Indian Archaean craton, a precise setting cannot be ascribed.
Paleoflow Analysis of Late Paleozoic Gondwana Deposits of Giridih and Adjoining Basins and Paleogeographic Implications
Authors: Tewari R. C. , Casshyap S. M.
Published: November 2024

The Late Paleozoic Gondwana rocks underlying the Giridih, Jainty and Saharjuri basins, and Dhakoi outlier of south Bihar comprise Talchir, Karharbari and Barakar Formations. The Talchir strata exhibit a facies change from conglomeratic in the Dhakoi outlier in the south to dominantly sandy, shaly to silty in the Giridih and other basins towards north. The Karharbari abounds in pebbly, very coarse, coarse to medium sandstone (~85% by volume) with thin interbeds of shale (~7%) and coal (~8%). In contrast, the succeeding Barakar is characterised by more of shale (~36%) and coal (~21 %) than sandstone (~43%) which is largely medium to coarse grained. Paleoflow analysis based on cross bedding and other directional attributes reveals a gradual shift with time in paleodrainage in that it was directed towards west-northwest (297 ±46°) during Talchir, northwest (343 ±42°) in Karharbari and towards north (359 ±: 50°) in Barakar. The uniformity of northerly paleoflow during Karharbari and Barakar times in the given area and in the adjoining Gondwana basins to the south is suggestive of a unified Gondwana basin in this part of peninsular India. It is inferred that the outlet of Gondwana streams in this part was dominantly northward.
Trace Element Studies and Origin of Magnetite-Quartzites of Tamil Nadu, India
Authors: Subba Reddy N. , Prasad C. V. R. K.
Published: November 2024

Magnetite-quartzites of Tamil Nadu associated with pyroxene granulites and gneisses occur in the Precambrian high grade granulite terrain. A study of distribution of ferride group of trace elements in separated magnetites suggests that the magnetite-quartzites and pyroxene granulites may have differrent modes of origin-metasedimentary and metavolcanic respectively. However, a volcano-sedimentary process for the magnetite-quartzites may have to be considered in view of the close association of metavolcanics.
Iron Formations in Archaean Granulite-Gneiss Belts With Special Reference to Southern India
Authors: Prasad C. V. R. K. , Subba Reddy N. , Windley B. F.
Published: November 2024

In Archaean granulite-gneiss belts there are banded iron formations (BIF) less than 20m thick which are weakly banded magnetite quartzites occurring in a supracrustal sequence of quartzites, mica schists, marbles and metavolcanic amphibolites. This sequence forms stratigraphic markers within voluminous intrusive tonalitic to trondbjemitic gneisses. These rocks are highly folded and metamorphosed to high amphibolite or granulite facies at 7-12 kb pressure in the lower Archaean crust. Such iron formations are well represented in Tamil Nadu, Southern Karnataka, Kerala and Andhra Pradesh in South India; in Hebei Province in China; Kola Peninsula, Stanovoy Range, and Ukraine in USSR; Kambui schists of Sierra Leone; Nimba series of Liberia; Limpopo belt of southern Africa; Imataca complex of Venezuela; Uivak gneisses of Labrador; and Amitsoq gneisses of West Greenland. They are obviously different in type and environment from the Proterozoic Superior type of BIF; it is shown here how they are different from the Archaean Algoma type of BIF. They were deposited in a quartzite-pelite-carbonate association and they lack the silicate-carbopate-sulphide facies of the Algoma-type which, in contrast, was deposited with a greywacke-flyschconglomerate- shale association in subsiding basins (Greenstone belts). Because they are dissimilar to the Algoma-type of BIF in both their sedimentary facies and tectonic environment (the granulite-gneiss belts are not highly metamorphosed greenstone belts), they should be given a separate status and we tentatively suggest they be termed the Tamil Nadu type.
Dehydroxylation and Dehydration as Parameters for Characterisation of Clays Part I: Montmorillonite, Attapulgite and Illite
Authors: Venugopal J. S. , Hirannaiah B. V. , Majumder S. K.
Published: November 2024

An improved TG and DTG method for identification of montmorillonite, i11ite and attapulgite has been described. The effect of the modified experimental conditions on individual dehydration pattern and the Bouncing dehydration phenomena have been discussed. New thermal parameters for clay characterization have been elucidated. This technique involves a simple instrument design which could be fabricated indigenously and can be used for species identification or even routine quality control work in laboratories which Jack sophisticated and expensive instrumentation.
Interpretation of Landsat Imagery of a Part of the Son Valley and its Correlation With Bouguer Gravity and Airborne Magnetic Anomaly Data
Authors: Gupta Arindam
Published: November 2024

A belt of volcano-sedimentary formations extending from the south-western margin of the area towards ENE along the Son valley has been traced on the LANDSAT imageries. These formations, which are considered to be the homotaxial equivalents of the 'Bijawar Series' occurring south of the Bundelkhand granite massif, rest on granite gneiss in the central and eastern parts of the area and are overlain towards north and south by the members of the Vindhyan and Gondwana Supergroups respectively. The significant litho-stratigraphic, structural and metamorphic features of the belt of volcano-sedimentary formations suggest that it may be classified as a 'Greenstone belt'.

Probable occurrence of the volcano-sedimentary formations and sub-crustal basic rocks beneath the Vindhyan and Gondwana Formations have been inferred in certain sections based on the interpretation of Bouguer gravity and airborne magnetic anomaly data.
The Khondalites of Orissa, India - A Case Confusing Terminology
Authors: Banerji P. K.
Published: November 2024

The paper traces the progressive metamorphosis of the term 'Khondalite' from 1902 to 1975 from a specific rock name to the collective group name of a suite of high grade metamorphic and metasomatic rocks and presents examples of the extent of compositional variations of these rocks from Dhenkanal, Angul and Tikarpara areas of Orissa. It is recommended that prevalent usage of the term 'Khondalite' as a mapping unit should be discontinued by general consensus, since the term can now be used only in the sense of a 'group'.
Cambrian Trace Fossils from the Spiti Valley, Himachal Himalaya
Authors: Bhargava O. N. , Kumar Gopendra , Gupta S. S.
Published: November 2024

Trace fossils Diplichnites spp., ? Dimorphichnus, Monomorphichnus spp., trilobite scratch marks, Gyrochorte, Gordia, ? Astropolithon, ? Scolicia, Planolites, Skolithos are reported from the Kunzam La Formation of the Haimanta Group of the Parahio section, Spiti valley. This fossil assemblage occurs 460m below the Middle Cambrian trilobite zone and 1620 m above Precambrian-Cambrian acritarch zone and may represent late Lower to Early Middle Cambrian age. These occur in sediments laid in a low energy environment.
Structural Studies Around Kathar, Udaipur Rajasthan
Authors: Mohanty Saradaprasad
Published: November 2024

The deceptively simple map pattern of quartzite, marble, and phyllite and mica schist, with nearly NS 'generalized strike' and steep dips of beds around Kathar in the Udaipur district, Rajasthan, conceals folds of two generations in large scale and structures of two additional phases in smaller scales. The folds of the first set (F1) are isoclinal with a pervasive axial plane cleavage (S1), which has largely blurred stratification in the more schistose rocks. These are buckle folds modified extensively by flattening. The S1 cleavage and F1 axial planes have been involved in tight to isoclinal upright folding on nearly NS-striking axial planes (F2). These folds have extensively reoriented the F1 axes and axial planes, but because of the style and orientation of the folds of the two systems, both the sets of axial planes have subparallel strikes in a major part of the area. Hook-shaped folds with double closures and orthogonal relation of stratification and S1 cleavage point to the presence of F1 folds. The F2 folds are also flattened parallel folds formed by a maximum compressive strain in a horizontal EW direction. Rare F3 folds with subhorizontal axial planes are gravity-induced. The F4 kinks with WNW-striking axial planes may represent structures formed by longitudinal shortening in the last stage of deformation.
Mode of Occurrence and Origin of Manganese Ores of Shimoga District, Karnataka
Authors: Krishna Rao B. , Srinivasan R. , Ramachandra B. L. , Sreenivas B. L.
Published: November 2024

Four types of manganese ores are distinguished: 1. Reworked metasedimcntary ore in Precambrian banded manganese formation; 2. Sedimentary oolitic/pisolitic ore associated with claystone; 3. Cavity filling/replacement type ore in weathered Precambrian phyllitic schists and laterites; 4. Bouldery-pebbly float ore in soils and laterite. The reworked metasedimentary ore is low in silica (~6%), high in Fe content (~26%) and its Mn/Fe ratio varies between 0.75 and 1.2. The oolitic/pisolitic ore on the other hand is high in silica (~14%), low in Fe ( ~17%) and Mn/Fe ratio of 1.7 and 2.1. Supergene processes, during Tertiary-Quaternary (7) have contributed significant quantities of sedimentary oolitic/pisolitic ore and minor amount of cavity filling/replacement type ore. The surficial exposures of reworked metasedimentary and oolitic/pisolitic ores have been subjected to mechanical disintegration and detrital accumulation with repeated breaks leading to extensive development or float ore in both laterite and soil profile.
Origin of Miliolite Rocks of Kutch-Microfaunal Evidences
Authors: Desai Geeta , Hardas M. G. , Patel M. P. , Merh S. S.
Published: November 2024

Miliolites occur within the Kutch highlands as thin horizontal sheets occupying topographic depressions or as obstacle dunes resting against the slopes of big hills. Sheet deposits of the low-lying ground, reveal a marine origin and are seen to consist of pellets and microfossils embedded in a micritic to fine sparry matrix. These valley-fill sheet deposits are characterised by a faunal assemblage typical of warm, clear, shallow, carbonate-rich sea, where terrigenous influx was poor. On the other hand, the obstacle dunes typically comprise aeolinites and appear to have developed during the regression of the sea, the strong winds having lifted the exposed carbonate sands and dumped them against the nearby hillsides. The higher strand line indicated by these marine miliolites could be related to one of the Quaternary transgressions.
Rare Minerals in Rajpura-Dariba Ores-Some Further Comments
Authors: Deb M.
Published: November 2024

Thirteen rare sulfides, sulfo-salts and native metals: geocronite, owyheeite, bournonite, polybasite/pearceite, native arsenic, enargite, electrum, aurostibite, pyrargyrite, argentite, argentopyrite, gudmundite, stannite (?l) have been identified in the Rajpura-Dariba ores on the basis of their optical properties including quantitative spectral reflectance. The localisation of these rare minerals in remobilised veins of massive chalcopyrite or galena-tenantite along with their crystallisation history suggests that most of the rare minerals formed by mobilization of the metals involved during regional metamorphism under amphibolite facies conditions.
Computer Modelling for Regional Groundwater Simulation and Estimation of Irrigation Potential For Vedavati River Basin* - Summary of Findings
Authors: Achutha Rao A. , Sridharan K.
Published: November 2024

Vedavati River drainage basin covering an area of 24,200 km2 falls in the monsoon depression zone and is prone to frequent drought conditions. The study is mainly directed to get as near a physical definition of the actual basin which would enable a systematic mathematical treatment. A mathematical model has been formulated and on the basis of this, a computer program was developed. The model was calibrated using field data and it is found useful in making reliable forecast of groundwater potential, for safe yield in order to prevent over exploitation.
Structure and Evolution of a Prograding Reservoir Delta in the Damodar River, India
Authors: Ray Pulak K.
Published: November 2024

The Damodar River is an ephemeral river with a braided stream pattern in many sections during the flood stage. Flood discharge is concentrated during summer monsoons. Damming of this river has produced two deltas, one corresponding to the live storage level ('upper delta') and the other at flood storage level ('lower delta'). The progradation of the upper delta over the topset beds of the lower delta coupled with fluctuations in lake level has produced a cyclic progradational deltaic sequence in the reservoir.

A significant zoning of the sedimentary structures is observed in the different parts of the delta. Parallel lamination is the major structure in the bottomset area; cross-stratification, ripple drift lamination and deformational structures predominate the foreset area; and horizotal and cross-stratification charactcrize the topset area. Cyclic sedimentation units with their characteristic sedimentary structures and grain size arc also characteristic of the topset area. The alluvial valley section is dominated by multiple units of a variety of cross-stratifications and some upper flow regime flat beds.
Ferroan Ankerite from the Chiknayakanhalli Schist Belt, Karnataka
Authors: Devaraju T. C. , Anantha Murthy K. S.
Published: November 2024

Mineralogy of ferroan ankerite with the composition (Fe, Mn)0.67 (Mg)0.38 (Ca)0.93 C2O6 is discussed with the aid of X-ray, DTA, and chemical data. The mineral typically occurs in the iron-enriched carbonate bands, which are either closely associated or enclosed within the iron formation. Available evidence suggests syngenetic chemical sedimentary origin for the mineral.
Anorthositic Enclaves in the Gneisses Around Holenarasipur Schist Belt, Hassan District, Karnataka
Authors: Hussain S. M. , Ahmad S. M.
Published: November 2024

Two occurrences of anorthosite enclaves in the 3.4 b.y. old gneisses surrounding the Holenarasipur schist belt are reported. The Mandagere enclave has An92 whereas, Arkalgud enclave has An83. Both the bodies are metamorphosed to higher amphibolite facies and exhibit granoblastic texture. They are associated with ultramafic enclaves. These occurrences along with the lunar type anorthosites of Holenarasipur Group greenstone belts are significant in early crustal evolution models.
Paleohydrology of Permian Gondwana Streams in Bokaro Basin, Bihar
Authors: Casshyap Satyendra M. , Khan Zahid A.
Published: November 2024

The clastic assemblage of Lower Permian Karharbari (70 m thick) and Barakar (800 m thick) Formations of the East Bokaro Basin shows a progressive upward decrease in grain size and scale of cross-bedding, illustrating a fining upward mega-cycle. A paleo-flow analysis reveals that the Gondwana sediments were deposited by streams which flowed towards north-northwest. The azimuthal variability is 2240 for Karharbari, 3304 for Lower Barakar and 4429 for Upper Barakar. Empirical relationships from modern streams are used to estimate various channel morphological and hydraulic attributes of ancient Karharbari and Barakar streams. Results indicate a progressive decrease in channel width and depth, channel slope. flow velocity and Froude number, with consequent increase in sediment load parameter, channel sinuosity for the Gondwana streams. as sedimentation continued from Karharbari through Lower to Upper Barakar. It is suggested that amelioration of climate through time possibly had a great control on river metamorphosis and sedimentation than tectonism.
Study of Beach Sand Movement by Fluorescent Tracer at Coondapur, S. Kanara District, Karnataka
Authors: Venkatesh K. V.
Published: November 2024

Three fluorescent tracer tests were carried out in the swash zone on a strip of the beach, south of Ganguli light house. An analysis of the tracer dispersion pattern reveals that generally the predominant vector of sand movement is along shore in a southerly direction. The grain velocity varies from 0.7 to 1.23m/min. It is observed to be higher in the finer sized grains than in the coarse grains. The computed rate of sand depletion for the first ten minutes is 1.99 kg/min. The result of the size analysis data shows that the sand grains tend to undergo differential motion with the coarser sized ones moving towards the shore and the finer ones seawards.
Geochemistry of Some Thermal and Cold Waters of Godavari Valley
Authors: Saxena V. K. , Gupta Mohan L.
Published: November 2024

Results of chemical analyses of fifteen thermal and cold waters of Godavari valley are reported. Agnigundala (Bhadrachalam) thermal water is of Na-Cl type and the rest are of Na-Ca-HCO3-SO4 type. It is likely that the Agnigundala geothermal system is associated with Archaean gneisses and is characterised with a reservoir temperature around 170°C. Other warm waters of the valley show low concentrations of dissolved solids and are similar to those which are associated with sedimentary rocks. It appears that the groundwater after movement to appropriate shallow depth, got heated up to moderate temperature (around 80-90°C). Thereby the basic chemical character of the water has not changed much due to movement, both downward and upward, through the same type of rocks.
A Note on the Burial Diagenesis of Clay Minerals in the Bengal Fan
Authors: Dilli Kailas , Rao C. N.
Published: November 2024

A thick (770m) pelitic section ranging in age from Quaternary to Middle Miocene encountered at the DSDP site 218 in the Bengal Fan has been investigated for the burial diagenesis of clay minerals based on x-ray diffractometry and partial chemical analysis. The clay minerals are dominated by illite, with minor amounts of montmorillonite, chlorite and kaolinite. All the clay minerals are descrete and detrital derived from the Himalayan hinterland. The clay mineral transformations are largely confined to compaction attendant on the escape of pore water and adsorption of K and Mg in the interlayer positions resulting in better organised illite, montmorillonite-illite and montmorillonite-chlorite mixed layers at depth. The sediments are considered to be in the early diagenetic stage of Dunoyer de Segonzac (1970).