bluuebunny/crossref_metadata_2025_split huggingface dataset:
Petro-Palynological Study of Churcha Seam, Sohagpur Coalfield (M.P.), India
Authors: Navale G. K. B. , Tiwari R. S. 
Published: November 2024

Abstract
Microscopic examination of polished pellets of Churcha coals reveals the nature of microfragmental constituents comprising mostly Durains. Petrological analysis has been made so as to assess the nature and distribution of different microconstituents. The miospore assemblage in this seam is a diversified one, consisting of 36 genera of triletes, monoletes, monosaccates, disaccates and others. The percentage frequencies of various genera have been determined. Petro-palynological constituents of this coal have been compared with those of other comparable beds in the Lower Gondwana of India.
Tertiary Sedimentation in the Andaman-Nicobar Geosyncline
Authors: Karunakaran C. , Roy K. K. , Saha S. S. 
Published: November 2024

Abstract
Andaman orthogeosyncline is continuous with Assam-Burma in the north and Indonesian geosyncline in the south. Andaman-Nicobar group of islands constituting the non-volcanic outer arc of the East Indian Orogen, has a more or less continuous history of Sedimentation throughout the Tertiary era commencing from sometime in the Upper Cretaceous right on to the Recent. The sedimentation gradually changed character with the tectonic development of the geosyncline through geologic time.
Euxinic sediments consisting of black pyritous shales with minor amount or dark impure limestone and gritty sandstones represent the earliest episode of geosynclinal sedimentation in the restricted basins formed by submarine ridges and valleys due to emplacement of ophiolites.
These ophiolites were subaerially denuded to some extent; and during Palaeocene-Lower Eocene, algal limestone and conglomerate and subsequently more finer fractions such as tuffaceous basic wacks and serpentinous and chloritic clay beds followed. Subsidence of the geosyncline which commenced with sedimentation of the Euxinic beds produced a uniform configuration of the geosyncline during Middle Eocene (Kirthar). Andaman flysch consisting of altetnatcly bedded graywackes, siltstone and grey illitic clay beds were deposited throughout the length and breadth in this regular geosynclinal basin till Upper Oligocene when a major orogenic movement overcame sedimentation.
Shallower basins formed within and in the outer margins of the rising emhryonic island arc were filled up during Lower Miocene with foraminifcrallimcstone and shale, and radiolarian and foraminiferal chalk beds.
Middle Miocene witnessed another major orogenic movement which brought out the present configuration of the island arc. Fossiliferous clays and limestones were deposited in peripheral basins during the Pliocene-Pleistocene which are partly raised during quite recent times.
The Koyna Earthquake
Authors: Gupte R. B. 
Published: November 2024

Abstract
A large part of Western Maharashtra experienced a severe earthquake on 11th December 1967. The earthquake caused great anxiety as the epicentre lay very close to the Koyna Dam of the vital Koyna Hydro Electric Project. Though the dam and other structures of the project suffered little damage, Koynanagar, the construction colony and Villages Within 25 km were devastated. The earthquake has puzzled all, as it took place in a region supposed to be stable; and It has become very difficult to offer a satisfactory explanation because of very imperfect knowledge of the geology of the earthquake area.
Layered Gabbro of the Igneous Complex of Phenai Mata, Gujarat State
Authors: Sukheswala R. N. , Sethna S. F. 
Published: November 2024

Abstract
Phenai Mata hill (Lat. 22°8'N., Long. 73°55'E.), believed to be a composite plug, is successively filled by basalt, gabbro, granophyre and nepheline syenite. The paper focusses attention on the layered character of the gabbro. Rhythmic layering is due to the repetition of thick anorthositic and gabbroic layers. Cryptic layering is marked by extreme variation in anorthite content of plagioclase. The differentiation trend is established by the chemical and petrographic studies of samples collected at regular intervals. Up to 600 feet the enrichment is towards both iron and alkali, after which the gabbro (tholeiitic) differentiates to a granitic residuum.
Pelitlc Hornfels Xenoliths in the Garnetiferous Granulites and Granitlc Rocks of the Kondavidu Area, Guntur District, Andhra Pradesh
Authors: Sadashiyatah M. S. , Subbarayudu G. V. 
Published: November 2024

Abstract
The geological setting, petrography and petrochemistry of the pelitic hornfels xenoliths of the Kondavidu area and the mineral transformations observed in them form the subject of this account. Based on mineralogy, the hornfelses have been classified into six types, and the minerals found in these types are garnet, andalusite, sillimanite, cordierite, corundum, anthophyllite and spinel. The instability of the almandine garnet of the composition Alm69+5 Py25+9 Sp2+3 And2+3 found in the pelitic hornfels is a dominant feature and it is attributed to the superimposition of thermal metamorpnism over regionally metamorphosed pelitic rocks in which the garnet is a stable mineral.
The mineralogical transformations, especially, the breakdown of almandine garnet to aggregates of cordierite, corundum, spinel and magnetite, and the formation of pseudomorphs of cordierite after garnet are attributed to the Oxidation of the garnet. The formation of fibrolite from cordierite, garnet, anthophyllite, corundum and even from potash felspar is due to metasomatism of alumina-rich solutions associated with the later injection metamorphism.
The chemical data indicate that the hornfelses are pelitic in composition and they belong to the pyroxene hornfels facies of contact metamorphism. The pelitic hornfelses owe their origin to the thermal metamorphism of the regionally metamorphosed pejites by the parent magma of the intermediate charnockites.
Cluster Analysis Approach to the Problem of Facies Classification of the Carbonate Rocks in the Krol Series
Authors: Gundu Rao C. 
Published: November 2024

Abstract
The Krol series in the Sub-Himalayas, include six lithological units, namely Infra Krol, Krol A.B.C.D. and E. Among these, A.C.D. and E. incorporate increasing thicknesses of carbonate rocks from A to E, with minor shale intercalations. Cluster analysis of 150 carbonate samples drawn from these four formations in five stratigraphic profiles between Mussoorie and Lansdowne, based on six petrographic attributes, has shown that the samples cluster into four meaningful groups. Interpretation of these groups reveals that the carbonate rocks of the Krol series fall into two broad facies or depositional mechanisms, one Krol A+C, of micrites and sparites, and the other, Krol D+E of calcicdolo and dolocalcicmicrites, and their variants. The earlier classification of Krol carbonates into four lithological units, A.C.D and E, from a facies point of view, seems to be unjustified. The depositional mechanism of A+C is succeeded by Krol D+E in the vertical profile. This supports the earlier view of Rao that the Krols represent a phase in the development of a basin centre evaporite sequence.
Petrochemistry of a Hornblende Porphyrite from Chityal, Andhra Pradesh
Authors: Soma Yajulu P. V. , Reddy M. N. 
Published: November 2024

Abstract
An isolated oval body of hornblende porphyrite occurring three km SE of Chityal, Nalgonda District, A.P. shows typical porphyritic texture both megascopically and microscopically. Euhedral primary hornblende occurs as pnenocrysts in a mesostasis of secondary actinolite and altered plagioclase. With the development of diopside at the expense of hornblende, the rock has acquired a granulitic texture while retaining the porphyritic habit.
Chemically the rock is characterised by low alumina and high magnesia and calcium. Among the trace elements, the high concentration of Cr, Cu, V and Co are in sympathetic relation with the major elements. The somewhat high values of Li, Sr and Rb, are thought to be partly due to introduction through water-enriched magmatic fluids which have metamorphosed the primary members of the rock. Tne rock appears to have suffered first a retrograde and then a prograde metamorphism.
Metamorphic Belts in Singhbhum, Manbhum and Chhota Nagpur, E. India
Authors: Ray S. , Gangopadhyay P. K. 
Published: November 2024

Abstract
Earlier studies on metamorphic zones in the metamorphic belts of Singhbhum, Manbhum and adjoining parts of Chhota Nagpur around longitude 86°E and between latitudes 22°45 Nand 23°40 N have been synthesised. Maps of Barrovian zones delineated by different workers in small areas have been coordinated into a regional zonal map.
Broad structural data of earlier workers plotted on the map depict that the pattern of extension of the zones over the whole region has a direct correlation with the plunges of the regional fold axes; higher grade zones occupy anticlinal cores with the lower grade ones succeeding them in the direction of the stratigraphic younging.
Granites, late syntectonic with tbe major folds on S" accompany most sillimanite zone outcrops. Andalusite occurs (i) across the chlorite to the kyanite zones along the southern fringes of the Dalma basic volcanics, and (ii) also sporadically. within sillimanite zone schists in association with sillimanite and kyanite.
Copper Mineralisation in the Bijawar Series Around Sonrai, District Jhansi, U. P
Authors: Singh K. K. , Goyal R. S. 
Published: November 2024

Abstract
The carbonate members of the Bijawar series (Precambrian) which are faulted against the Bundelkhand granites, show copper mineralisation at several localities between Sonrai and Tori. The ore bodies are highly oxidised and are chiefly localised along the fault and shear zones. Both primary and secondary wall rock alterations have been observed. Chalcocite, cuprite and malachite are the main copper ore minerals, with minor amounts of covellite, tenorite and chalcopyrite. Goethite along with malachite forms the conspicuous mineralogical guide for prospecting on the surface. The present surface studies indicate that the copper mineralisation is epigenetic and suffered deep oxidation along weak zones. The possibility of supergene sulphide enrichment is poor due to presence of reactive carbonate wall rork.
Karstic Limestones in Parts of Raipur District, Madhya Pradesh and their Groundwater Possibilities
Authors: Adyalkar P. G. , Phadtare P. N. 
Published: November 2024

Abstract
The southernmost parts of the Raipur district, covering about 5,600 sq km of area between the north latitudes 20°30' and 21°30' and the east longitudes 81°30' and 82°15' and forming part of the extensive saucer-shaped Raipur basin of the Chhattisgarh region of Madhya Pradesh, has been studied by systematic geohydrological work.
The limestones of the area have high secondary permeability and are observed to be rich in groundwater potential. The large vertical thickness and considerable lateral extension of carbonate rock aquifers indicate scope for development of groundwater.
Mineralogy and Origin of the Rajahuan Bauxite Deposits, Uttar Pradesh, India
Authors: Swarup Prem 
Published: November 2024

Abstract
Deposits of bauxite were discovered by the Directorate of Geology & Mining, U.P. on the bed rock of Upper Vindhyan sandstone at Rajahuan, district Banda, Uttar Pradesh in the year 1965. This paper deals with the mineralogical studies done on the laterite profile of Rajahuan with the help of X-ray diffraction method. A brief description of the members of the profile along with the development and distribution of chemical constituents and minerals is given. In the bauxite, gibbsite is the chief mineral with subordinate boehmite, sometimes with minor diaspore. Anatase is fairly high. On the basis of field and laboratory data it is concluded that the Rajahuan laterite profile represents an in-situ residuum formed in a regular weathering profile with the bauxite forming in the zone of aeration, which is underlain by cavernous laterite developed in the zone of fluctuation of water table, and the basal lithomarge formed within the zone of saturation. It is suggested that the parent rocks of this residuum were a sandstone-shale sequence.
Time-Relation of Poly Metamorphic Recrystallisation in the Precambrian Rocks of the Sonapet Valley, Eastern India
Authors: Bhattacharyya D. S. 
Published: November 2024

Abstract
Three phases of high grade metamorphism are recognised here. These are dated with reference to the four phases of deformation recognised in this area. It is concluded that the index minerals are progressive in time and space; the metamorphisms are also synkinematic to post-kinematic. Zonal patterns are analysed and it is seen that these show synchronous fold shapes. Folding of the geoisothermals seems to be the best explanation for the metamorphic episodes.
Copper Mineralisation in Karnataka, India
Authors: Radhakrishna B. P. 
Published: November 2024

Abstract
The known occurrences of copper ore in Karnataka are grouped under five main groups (1) those associated with ultrabasic complexes (2) those associated with quartzites and quartz schists of Lower Dharwars (3) those associated with shear zones in the greenstone schists-volcanic assemblages comprising pillow lavas, agglomerates and tuffs (4) hydrothermal lode deposits and (5) those associated with major fault zones.
Targets for further search for copper are indicated to be the layered ultrabasic complexes, quartzitic sediments of Lower Dharwars, shear zones in submarine volcanic assemblages of andesitic composition, metamorphosed shales and graphitic schists, brecciated and mylonitized zones associated with major faults of great horizontal and vertical extent.
Tipam Group in the Subsurface of Upper Assam Valley, South of Brahmaputra
Authors: Shrivastava P. K. , Ganeshan S. , Ray D. 
Published: November 2024

Abstract
The Tipam group in the subsurface of Upper Assam valley is discussed in this paper. The group is divisible into four formations in'ascending order: the Geleki sandstone, the Lakwa clay, the Nazira sandstone, and the Girujan clay. Within the Geleki sandstone a basal member, the Safrai, and Teok sandstone member within the Girujan clay are mappable. These rock-stratigraphic units are systematically described. The group unconformably overlies the Barail group, and is overlain unconformably by the Namsang formation. The problem of the Surma group in the area is discussed and it is concluded that this group is not developed here. Its age equivalents form a part of the Geleki sandstone. The age of the Tipam group ranges from Middle Miocene to Pliocene. The present subcrop Tipam rocks were formed by fluvial processes in an intermountain continental basin. Commercial accumulation of oil in these rocks and older formations has fed to extensive deep drilling which provided data for the present study.
Structural History of the Saladipura Pyrite-Pyrrhotite Deposit and Associated Rocks, Khetri Copper Belt, Rajasthan
Authors: Ray Sumit Kumar 
Published: November 2024

Abstract
Elucidation of the structural geometry and structural history of the area around Saladipura in the southern part of the Khetri copper belt, Rajasthan, helps in precise dating of formation of the massive sulphide deposit with respect to the different phases of deformation affecting the area. The pyrite-pyrrhotite deposit of Saladipura occurs almost along the contact of two lithological units and is traceable over a strike length of about 7 km. Rocks of the Delhi group exposed in this area have been folded into a series of normal, upright to inclined folds F1 with NE-SW trend. Formation of sulphides in the area can be dated to be earlier than the first recognisable phase of deformation F1 folding. Sulphides of the ore body bear imprints of all the phases of deformation affecting the associated metasediments of the Delhi group and distribution of sulphides within the ore body often define stratification. All these evidences indicate syngenetic primary nature of the sulphides, which have undergone textural modification, mineralogical reconstruction and (re)mobilisation in the course of regional metamorphism and deformation.
Geochemistry and Origin of the Peninsular Gneisses of Karnataka, India
Authors: Divakara Rao V. , Naqvi S. M. , Satyanarayana K. , Hussain S. M. 
Published: November 2024

Abstract
Major and trace element analyses of gneisses from parts of the Karnataka State, reveal heterogeneity in their chemical, modal and normative compositions. On the basis of chemical differences it is suggested that the parent material for these gneisses was pelitic/arkosic in nature. Heterogeneity in their composition is attributed to their age difference, degree of granitisation and migmatisation to which the pelitic/arkosic parent material was subjected.
Quantitative Evaluation of Bouguer Anomalies in Puranpur Area of the Ganga Basin
Authors: Datta A. N. , Trehan D. K. , Choudhury S. K. 
Published: November 2024

Abstract
Bouguer gravity data of the Ganga basin could not be interpreted earlier quantitatively, as it was believed that the isostatic effect of the Himalayas masked all the local anomalies. The present work, however, suggests that the contribution of substantially thick low density post-unconformity sediments is more in masking the local anomalies than the isostatic effect.
The gravity data in Puranpur area of the Ganga basin have been interpreted in terms of basement depths after removal of the effect of the post-unconformity sediments, whose disposition is fairly well known from the seismic data. In the Puranpur depression the maximum sedimentary thickness is about 6000 metres. The pre-unconformity sediments in this depression may be different from those in the adjoining areas, to the west and south. The northeastern limit of this depression is a basement ridge on which interesting structural features are located.
In the northern part of the area the basement structures exhibit a WNW-ESE trend indicating that this area probably belongs to the Krol basin. In the southern part, the trend is dominantly E-W, but is disturbed by a number of NE-SW trending features. The former is probably governed by the basement rocks belonging to the Bundelkhand massif while the latter are due to the continuance of the Aravalli trend of the peninsular area.
Geochemistry of the Precambrian Alkaline Rocks and Carbonatites of India-Gaps in our Knowledge
Authors: Sethna S. F. 
Published: November 2024

Abstract
The carbonatites in India are closely associated with alkaline rocks, and are restricted to the stable continental area along major deep-seated faults. The detailed structural settings of all the carbonatite-alkaline complexes are yet to be worked out. Alkali metasomatism (fenitisation) that commonly accompanies carbonatite eruption also remains to be studied for most of the carbonatites so far discovered. Very little geochemical work has been done to prove or disprove the concept of associational major and minor element characteristics of the alkaline rocks and carbonatites. Whereas highly diagnostic isotope ratios have been reported for the igneous carbonate rocks from various parts of the world, only very few determinations have been done on the Indian carbonatites. Since experimental data have proved the magmatic origin of carbonatites and it is presumed that carbonatites are secondary magmas out of either kimberlitic or alkali-basaltic magmas, the ultrabasic rocks associated with the alkaline rocks and carbonatites of India need to be studied from the point of view of establishing the parent magma. Carbonatites have proved to be hosts for numerous economic mineral deposits. It is, therefore, necessary to undertake extensive geochemical surveys of the known outcrops as well as of the soils overlying and surrounding the outcrops.
Geology and Mineralisation in the Southern Parts of Bundelkhand in Lalitpur District, Uttar Pradesh
Authors: Prakash Ravi , Swarup Prem , Srivastava R. N. 
Published: November 2024

Abstract
The rocks of the Archaean basement complex and the overlying sedimentary sequences in the southern parts of the Bundelkhand in Lalitpur-Jhansi region, Uttar Pradesh are divided into tectonic blocks, within which broad but distinct stratigraphic units are recognised and classified. Recent mapping suggests that the entire area was subject to two major phases of sedimentary-volcanic process before regional granitisation during the Archaean. Granitisation, in preferred tectonic block, led to the development of an intra-cratonic belt controlled between lineaments, within which the younger Bijawar-Vindhyan basins developed.
The results of exploration done so far suggest that base-metals, gold, uranium and possible nickel mineralisation occurs within the different stratigraphic-tectonic environments recognised in this area.
Genesis of the Barakar Sediments of North Karanpura Coalfield, India as Revealed from Petrography and Provenance Study
Authors: Mukhopadhyay P. K. 
Published: November 2024

Abstract
The petrographic and provenance study of the sediments of Barakar Formation in North Karanpura Coalfield reveals the presence of cyclic sedimentation from coarse to fine clastics, coal and clay arkose. The evidences indicate that the sediments were deposited in a broad river channel with intermittent flooding.
Metamorphism and Petrogenesis of the Dalli-Rajhara and Ari Dongri Iron Formations, Madhya Pradesh
Authors: Mukharya I. L. 
Published: November 2024

Abstract
The minerals present in the iron formations are divided into oxides, silicates and sulphides. Hematite occurs in all the three stratigraphic members and magnetite is present mainly in Ari Dongri. Sulphides are present only in the Ari Dongri Iron Formation. The amphibole group is predominant amongst the silicates. Stilpnomelane and minnesotaite are also present.
The rock types are phyllites, schists, talcose and ferruginous shales, iron-formation, amphibolites, traps, granites and gneisses. The iron-formation consists of banded hematite-quartzites, shales and banded magnetite-quartzites, The unaltered banded hematite-quartzites are of two types-granular and non-granular or slaty. The latter is more common than the former. The rocks which are associated with the ore deposits are ferruginous shales and banded hematite-quartzites. The amphibolites are considered to be metabasites. The basic intrusives are predominant at Ari Dongri.
The silicates are secondary derived by diagenetic or low grade metamorphic effects. Metamorphism increased the grain size in case of hematite and magnetite. There is no coincidence of the metamorphic zones with the boundaries of the stratigraphic units. The cross-cutting relations of the acidic and mafic rocks are thought to be probably related to the last stages of metamorphism.
Carbonatite Alkali Complex of Samalpatti Dharmapuri District, Tamil Nadu
Authors: Subramaniam V. , Viladkar S. G. , Upendran R. 
Published: November 2024

Abstract
Dunites, pyroxenites, alkali syenites and carbonatites form the complex. The complex intrudes in a discordant fashion, hornblende gneisses which form the country rock.
The carbonatites are distributed mainly in pyroxenite as fracture fillings and to a lesser extent as dykes in syenites. The carbonatite bodies form a distinct but discontinuous ring. The calcite-dolomite carbonatite and para-ankerite carbonatite are the main types. Varieties having mica, monazite, riebeckite and ilmenite are identified. Quartz-baryte-galena veins, pegmatites of syenitic composition and albitites are associated with the carbonatites. Evidences for fenitisation are not much. Feldspathoids, normally associated with carbonatite activity are absent. Xenoliths of gneisses, pyroxenite and syenite in carbonatites, compositional banding and primary foliation, are some of the features of the carbonatites. On the basis of mineral assemblage, the temperature of formation of this complex is assigned 325°C. Analyses indicate relatively high values for barium, cerium, yttrium, zirconium, vanadium and boron.