bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iron-Formation of the Chiknayakanhalli Greenstone Belt, Karnataka, India
Authors: Devaraju T. C. , Anantha Murthy K. S. , Khanadali S. D. 
Published: November 2024

Abstract
The iron-formation of the Chiknayakanhalli (CN Halli) greenstone belt constitutes the youngest lithological unit of the late Archaean supracrustal geosynclinal sequence (3 to 2.4 b.y. old) which unconformably overlies the older (3 b.y.) granitic gneisses. They are consistently located in the core parts of the synclinal fold structures and occur over-lying either carbonates or chlorite schists. There are four main sedimentary facies, viz., oxide - (OF), mixed oxide-silicate - (MOSF), mixed oxide.silicate carbonate-(MOSCF), . and carbonate-facies-(CF) constituting the iron-formation, All the facies types are strongly banded on metre to micron scale and frequently show small to large scale fold structures of both depositional and tectonic origin. While the lighter bands account for 43 to 57 per cent of the rocks and contain either silica (chert to quartz) and lor silicate (grunerite), the dark bands are chiefly made up of hematite, magnetite and goethite in OF, magnetite in MOSF, siderite and magnetite in MOSCF and ankerite-ferroan ankerite in CP. Although some of hematite and goethite could be interpreted as secondary after magnetite, a good proportion of these and the bulk of magnetite are syngenetic sedimentary. Grunerite appears to have been derived by the metamorphism of the precursor minnesotaite. The striking simplicity in chemical composition and distinctly low minor and trace element contents .are in accordance with the formation of eN Halli Iron-Formation through the process of inorganic chemical deposition. The carbonates underlying the iron-formation show upward iron enrichment and the iron-formation is interpreted as terminal phases of chemical sedimentary carbonate deposition in an essentially 'quiet' and' closed' environment.
Main Features of the Precambrian Banded Iron-Formations of Finland
Authors: Laajoki Kauko 
Published: November 2024

Abstract
Precambrian banded (cherty) Iron-Formations are encountered in Finland in four main rock associations: 1) Late Archaean (c.2800 Ma) occurrences hosted either by greenstones or turbiditic schists in eastern and northern Finland. 2) Early Proterozoic (Lapponi) (&gt;2200 Ma) iron-formations associated closely with metavolcanics in Central Lapland. 3) Early Proterozoic (Karelia) (c. 2050 Ma) metasedlment-hosted occurrences in Kainuu. 4) Early Proterozoic (Svecofennia) (c. 1900 Ma) occurrences hosted either by metavolcanics or metasediments in southern and central Finland.
The occurrences are mostly relatively small and of low grade (Fetot mostly below 30%). With the exception of central Lapland, the occurrences are relatively highly metamorphosed. representing the medium grade as revealed by the fact that grunerite or other iron-rich amphiboles and garnet are commonly present; pyroxene is encountered in only one locality. The low grade Kittila occurrences in Lapland are distinguished by stilpnomelane, biotite, Fe-chlorite and carbonate with minor minnesotaite.
Chemically, the Finnish occurrences are like the iron-formations described from the other Precambrian shields. The Kainuu occurrences and at least a part of the Lapponi occurrences are. however, unusually rich in phosphorus; the average P205, content being c. 2.5% at Puolaoka. Phosphorus occurs as discrete phosphorite (apatite) bands some millimetres thick. Manganese-bearing types are encountered in Kittila and Kainuu.
Proterozoic Conglomerates of Bar, Debari, Umra and Jaisamand in South Central Rajasthan - A Study in Strain Analysis
Authors: Bhattacharya P. , Banerjee D. M. 
Published: November 2024

Abstract
Dunnet's matching curve technique has been applied for evaluating the finite strain of basal conglomerate clasts occurring at the base of Delhi as well as Aravalli rock formations. The study revealed that deformation shown by the enclosing clasts are close to the theoretical values.
Secondary and Primary Growths in the Zircons from Paragneisses and Migmatites of Arvika (Sweden) and Nelaug (Norway) Regions
Authors: Gupta L. N. 
Published: November 2024

Abstract
Secondary growths which include overgrowths, outgrowths, and multiple growths are formed during metamorphism and partial melting. Primary growths include growth twins and parallel growths. Twinning may occur during the early crystallization of zircon in magmatic rocks. The process of synneusis may result in parallel growths or attachment of zircons that have initially undergone separate growth histories.
The occurrence of primary growths in paragneisses and migmatites is due to their derivation from magmatic sources and their survival during mechanical transportation and crushing of the samples at the time of separation.
Seismicity of the North-East India Region Part II: Earthquake Swarms Precursory to Moderate Magnitude to Great Earthquakes
Authors: Gupta Harsh K. , Singh H. N. 
Published: November 2024

Abstract
Since 1897, ten earthquakes of M ≥ 7½ have occurred in north-east India region and its vicinity including the great earthquakes of June 12, 1897 and August 15, 1950, both of M 8.7. The last earthquake belonging to this category, occurred on August 17, 1952. With the exception of three earthquakes, others are found to be associated with the epochs of background/normal seismicity, precursory swarm, quiescence and mainshock (and the associated foreshocks and aftershocks). In our investigations, the earthquake data have been critically examined and taking due care of prevalent location - capabilities and other parameters. The mainshock magnitude (Mm) is related to the magnitude of the largest events in the swarm (̅Mp) and the time interval Tp (in days) between the beginning of the swarm and the main shock. The regression equations are:
Mm = 1.37 ̅Mp - 1.41
and Mm = 3 log10 Tp - 3.27
Installation of the World Wide Standard Seismograph Network during 1962-63 improved the earthquake detection and location capabilities considerably in the northeast India region and all earthquakes of mb ≥ 4.5 are being located. Consequently, for the period 1963 through 1985, we have investigated all events of mb ≥ 6.1 for occurrence of precursory swarms. Ten such events have occurred, four of which in a quick succession in the Arakan Yoma fold belt within a time span of six months only, and constitute a well defined swarm. Two other earthquakes are possibly gap events of Arakan Yoma swarm. Out of the remaining four, three are found to be associated with epochs of normal/background seismicity, precursory swarm, quiescence and main. shock (and the associated foreshocks and aftershocks). The latest killer earthquake in northeast India of Dec. 30, 1984 of mb 5.6, which occurred in the vicinity of the Arakan Yoma fold belt and Shillong Plateau, was preceded by a well-defined precursory swarm and seismic quiescence.
The most important thing is to recognize the precursory swarms and quiescence in real time, before the occurrence of the main shock. We believe to have recognized one such sequence in the vicinity of Arakan Yoma fold belt. On the basis of Mp and Tp values, lateral extent of the swarm activity and the fact that no event of mb ≥ 6.1 has occurred since 1975 in the preparation zone defined by the 1963-65 swarm, we estimate that an earthquake of M 8 ½ could occur any time from now in an area bound by 21°N and 25½°N latitudes and 93°E and 96°E longitude, with a focal depth of 100±40km.
We have also recognized a region in Eastern Syntaxis where repeated swarms have occurred during 1968, 1977 and 1980. The largest events in these swarms, however, were only of mb 5 and the swarms were very localized. These may have been caused by magmatic emplacement at shallow crustal depths.
A Note on Fossil Bovids from Nittur, District Bellary, Karnataka
Authors: Sathe V. G. , Salahuddin  , Badam G. L. 
Published: November 2024

Abstract
A rich fossil bovid assemblage recovered from Nittur in Karnataka in association with Lower Palaeolithic tools is one of the very few fossil discoveries made from the Krishna basin. The antiquity of man-animal relationship in the area is pushed back to the Late Pleistocene times. The discovery has also a bearing on the palaeoecological conditions obtaining around Nittur during Late Pleistocene period.
Dolomitisation of Micritic Limestones in Deeper Water Proterozoic Limestone-Shale Alternations, Larji Window, Lesser Himalayas, Northwest, India
Authors: Gundu Rao C. , Sharma Dwijendra K. 
Published: November 2024

Abstract
The dun pink micritic limestone and purple shale alternations unit resemble the deeper Water carbonates. The dull pink micritic limestones of the unit give a weak 1:4 dilute acid reaction and negative test for Mann's stain solution for dolomite. Despite this, the samples showon XRD Charts, a prominent peak for ordered dolomite (104) 2.88 Å to the total exclusion of calcite. The important point of the present example is, despite complete dolornitisation, the resulting dolostone neither shows change in porosity nor in size and shape of the micritic particles. The kind and intensity of dolomitisation observed in the present example are difficult to explain in terms of the existing dolomitisation models for deeper water limestones.
REE Geochemistry and Petrogenesis of Ultramafic Rocks of Chalk Hills, Salem
Authors: Kutty T. R. N. , Murthy S. R. N. , Anantha Iyer G. V. 
Published: November 2024

Abstract
REE geochemistry of plagioclase-free, plagioclase-bearing and titanoclinohumite-bearing ultramafic suite of Chalk Hills is presented. The rare earth elements are determined by spark source mass-spectrography combined with a preanalytical chemical concentration reaching ± 4 accuracy and 0.01 ppm detection limit. Plagioclase-free ultramafics are 10 times LREE depleted. while HREE abundance is 1-2 times those of chondrite. Since the samples are not serpentinised, these REE patterns are considered to be primary and compare well with those of high temperature peridotites, particularly on CeN-YbN diagram. The plagioclase-bearing ultramafics and the gabbros have LREE contents 4-22 times chondritic, while the HREE varies from 2-12. The REE patterns of ultramafics from the smaller body show uniform increase in (La/Yb)N ratios from 7 to 15. Higher abundance levels of incompatible alkali elements which do not correlate with the MgO contents, may suggest metasomatic introduction of these elements into the smaller body.
Petrogenetic modeling, based on partial melting of spinel peridotites as the source rocks with 2 times chondritic abundance, points towards the residual nature of the plagioclase-free ultramafics after extracting 8-10% of the melt. On the other band, the observed REE patterns of the plagioclase-bearing ultramafics and the gabbros not only indicate the absence of rocks more siliceous than syenogabbros but also suggest that they represent compositions of a depleted parent melt from which they originated. Thus the ultramafic association of Chalk Hills is distinctly different from the igneous suites associated with ophiolites and alpine peridotites.
Proto-Penner River Course and its Role in the Distribution of Alluvial Diamonds: An Evidence from Landsat Data
Authors: Chetty T. R. K. , Satyanarayana Rao R. 
Published: November 2024

Abstract
A possible Proto-Penner river course, running in a NNE direction from the elbow of capture near Penna Ahobilarn and joining the river Tungabhadra near Kurnool, in Andhra Pradesh, has been inferred from a Satellite Remote Sensing based geomorphic study. Occurrence of lag-gravel and diamonds, remnant alluvial tracts, anomalous drainage pattern, etc. are cited as evidences. Some potential areas such as remnant alluvial patches along Proto-Penner river course and alluvial plains along adjacent streams and topographic depressions are indicated as possible areas for alluvial diamond exploration. Various geomorphic features occurring in Archaean denudational hill province and Cuddapah structural hill province are delineated.
A Note on the Lower Miocene and Recent Species of the Ostracode Genus Loxoconchella from India
Authors: Khosla S. C. , Nagori M. L. 
Published: November 2024

Abstract
Three taxa of the ostracode genus Loxoconchella are described and illustrated. Of these, two species - L. multibullata n. sp, and Loxoconchella sp. - are recorded from the Quilon beds (Lower Miocene) of Kerala and one species - L. dorsobullataokhaensis n. subsp, - from the shallow water near Okha Port, Gulf of Kachchh.
Satellite Magnetic Map and Tectonic Correlation
Authors: Mishra D. C. 
Published: November 2024

Abstract
The satellite magnetic data (MAGSAT) over India is analysed with reference to the major tectonic elements of the country. The recorded magnetic anomaly varies from +6 gamma over the eastern part of the Indian shield to -9 gamma over the Himalayas. Deccan Trap is characterized by 'nosing' of the magnetic contours. Tibet plateau and Shillong massif show distinct magnetic anomalies. The magnetic crust derived from this data depicts a variation from 30 km under the Cambay basin and the western part of the Narmada-Son lineament to 40 km under the Aravallis and 42 km under the-Singhbhum and the Dharwar cratons. The general thickness of the magnetic crust under the Himalayas is 35-36 km with a thickening of 2-4 km under the Tibet plateau and the Shillong massif.
Non Penetrating Wells for Characterising Aquifer Constants
Authors: Gupta S. K. 
Published: November 2024

Abstract
Hydraulics of flow in cavity wells can be aproximated to unsteady state flow in spherical coordinates. The equation proposed by Chauhan et al (1975) can be used for non-leaky aquifer conditions placing the piezometer at a distance exceeding 20 times the radius of the cavity. Solutions to the equation can be found graphically by match point technique or using inverse 'lerfc' function. Solutions are yet to be developed for finite radius wells in leaky aquifer conditions or when source boundaries are present.
Global Hydrogeological Cyclicity
Authors: Bogomolov Yu. G. , Usenko V. S. , Beletsky S. S. 
Published: November 2024

Abstract
An in-depth analysis of the origin of the lithosphere and hydrosphere from a global perspective indicates a close relationship between the geotectonic rhythms and hydrogeological cycles corresponding to the Caledonian, Hercynian and Alpine Orogenies. The processes of evolution of the hydrogeological cycle are the result of the unique properties of water. The beginnings of water circulation in the earth's history are elucidated using the fundamental concepts of geological and hydrogeological processes. Some of the practical conclusions that emerge from such a study are: (i) After the hydrosphere had appeared on the earth's surface, two unique stages are conspicuous: first an increase in the volume of oceans and later an increase in river waters as a result of addition from groundwater discharge. (ii) The hydrological cycle may be viewed as an independent natural mechanism in the upper shells of the earth.
Aquifer - Water Table Aquitard Model for Hard Rock Areas
Authors: Sridharan K. , Mohan Kumar M. S. , Lakshmana Rao N. S. 
Published: November 2024

Abstract
Two layered models are gellerally accepted to represent groundwater flow in fractured media. This paper presents a rigorous numerical analysis of an aquifer - water table aquitard system, which may be applied for hard rock areas. In this study, the water table aquitard considered is compressible and the system is of two-layered nature. The model is quasi three dimensional and takes into account the vertical variations of head in the aquitard. The water table is treated as an unknown boundary.
A new iterative scheme for analysing aquifer-water table aquitard system has been presented. It has been found that rigorous analysis may be necessary in the well field solutions while approximate methods are sufficient for a regional study in hard rock areas.
Application of Kriging Techniques in Groundwater Hydrology
Authors: Marsily Ghislain de , Ahmed Shakeel 
Published: November 2024

Abstract
Many common parameters of groundwater hydrology are found to be "regionalized variables", i.e. they are highly variable but exhibit a certain spatial structure. Geostatistics, which has been developed for the estimation of the grade of ore bodies, is found to be equally applicable to groundwater problems as well.
The basic principles of a geostatistical estimation are outlined, and the usual kriging equations given. The extension of kriging to multivarliate problems is also described. An example is given of the use of these methods for the estimation of the transmissivity using a limited number of observations, both pumping test and specific capacity data. The study was carried out on the chalk aquifer (3000 km2) lying partly in northern France and partly in western Belgium. Both values of transmissivity (72 data points) and specific capacity (235 data points) show a log-normal distribution. All the three methods of cokriging, kriging combined wlth linear regression and kriging with the mean as a function of another variable yielded same results for the transmissivity values estimated.
Record of Cyclolobus walkeri from the Base of Member-C Zewan formation, Kashmir
Authors: Kalia Prabha , Pande Prabhas 
Published: November 2024

Abstract
The Upper Permian index species Cyclolobus walkeri is recorded and described from the base of C-Member, Zewan Formation, Guryul ravine, Sri nagar, Kashmir. On the basis of the present record of the Upper Permian C. walkeri (Diener, 1903), C-Member is correlated with the mid-Dzulfian Chhidruan Stage. By extension, the units above and below belong to the Dzulfian series though the existing record of fauna is inconclusive regarding the age of the members B and D.
Crustal Structure and Delineation of Gondwana Basin in the Mahanadi Delta Area, India from Deep Seismic Soundings
Authors: Kaila K. L. , Tewari H. C. , Mall D. M. 
Published: November 2024

Abstract
A Gondwana graben with a maximum sedimentary thickness of about 2.8 km has been mapped in the Cuttack-Kendrapara area of the Mahanadi basin. This graben is bounded by faults towards its north and south. The velocities which are about 3.9 km/sec around Cuttack change to 3.4 to 3.2 km/sec towards Kendrapara. South of the Gondwana graben lies the shallow basement area, the shallowest part of which is at a depth of about 200 metres under alluvium (velocity 1.6 to 2.0 km/sec). This basement high probably formed the barrier northwest of which the Gondwana graben was formed. Southeast of this, in the coastal area and in the adjacent offshore region, new basins developed during Tertiary period which received Tertiary and younger sediments. Two coastal depressions which may be extending into the Bay of Bengal have been identified: the Konarak depression which received a maximum sedimentary thickness of about 2400 metres on land and the Paradip depression which has a maximum sedimentary thickness of 2200 metres on land. These depressions are fault-controlled and the velocity over the major part is 2.4 km/sec followed by a deeper layer with velocity 4.2 km/sec in the Konarak depression which may be represented by limestone formations or basalt flows.
In the crustal depth sections, there are velocity discontinuities at average depths of 6.0, 17.5, 20.5 and 34.5 km along various profiles which have been mapped fairly weIl. The crustal velocity model in the Mahanadi delta area shows a velocity of 1.6 km/sec at the top which is followed by a velocity of 2.45 km/sec at about 0.3 km depth. The velocity in the basement is 5.9 km/sec at a depth of 1.1 km which changes to 6.45 km/sec at 6.0 km depth. A low velocity layer about 3.0 km thick with velocity 6.0 km/ sec is indicated at 17.5 km, velocity changing to 7.1 km/sec at 20.5 km depth. The velocity at the Moho depth 34.5 km, changes to 8.1 km/sec. The crustal thickness in this area is found to be 30-34 km which is smaller than that in the Indian shield (40 km) and in the Narmada-Son lineament area (37-42 km).
Distribution, Factor Analysis and Ecology of Benthic foraminifera within Inner Shelf Regime of Vengurla-Bhatkal Sector, West Coast, India
Authors: Nigam Rajiv 
Published: November 2024

Abstract
One hundred and two taxa of benthic foraminifera are reported from the neritic environment (15-60 m) of Vengurla-Bhatkal area. Q-mode factor analysis reveals 6 important foraminiferal assemblages accounting for 92% of the information given in original data matrix. The assemblages are - Nonion - Bulimina Ammobaculites, Bolivina, Bulimina - Nonionella - Ammobaculites Nonionella - Bulimina and Ammonia. Based on the ecology of the fauna it is concluded that a general hyposalinal environment prevails in the study area. Geographical distribution of well-known hyposalinaI species/assemblage can be used to study the spread of brackish water along the coastal area.
Lonar Lake and Co-Linear Carbonatites of Western India
Authors: Mishra Satya Prakash 
Published: November 2024

Abstract
The carbonatites of Mer Mundwara and Sarnu in Rajasthan and the Lonar lake of Maharashtra are located on a NW-SE trending straight line. This, when extrapolated further. meets the shore line of the Peninsular Shield of India where it turns sharply from N-S to NE-SW direction. This geometric alignment extends through Mt. Abu pluton, ultramafic bodies of Abu Road and Jobat areas, the Pb-Zn-Cu deposit of Ambaji and Pb-Cu occurrences of a part of Agnigundala belt and a group of thermal springs in Maharashtra. The line is sub-parallel to the join of Precambrian volcanic vent of Mandli and the Newania carbonatite of Rajasthan along the extension of Godavari graben. The empirical pattern signifies that the Lonar is located along a line of possibly deep tectonic significance.
Influence of Coastal Processes Along the Modern Delta Front of Godavari in Andhra Pradesh
Authors: Sambasiva Rao M. 
Published: November 2024

Abstract
Studies reveal that during sw monsoon period, the beach is subjected to erosion and during the NE monsoon period there is more addition of material. The reasons for the same have been analysed based on the movement of currents and water discharge into the sea through various distributaries of river Godavari. Overall there is deposition of material than erosion along the present delta front. The present rate of progradation is about 2.5km over a period of 40 years at the confluence of Gautami Godavari. This does not depict the overall growth of the delta front. The progradation along the present front however, is not uniform and depends upon the dominating processes within the region.
Geomorphic Evolution of Shetrunji Estuarine Delta, Saurashtra
Authors: Ganapathi S. , Merh S. S. 
Published: November 2024

Abstract
The various geomorphic features point to a sequence of transgression (+20 m), regression (-10 m), transgression (+6 to +8 m) and regression (present-day sea-level) which acted over a coastline, which also showed differential movement along the Shetrunji Fault.