bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineralogical and Chemical Characteristics of the Serpentinites from Boula-Nausahi Igneous Complex, Orissa
Authors: Mohanty J. K. , Sahoo R. K.
Published: November 2024

The ultramafic rocks of Boula-Nausahi igneous complex have undergone extensive alteration resulting in the development of serpentinites. Petrographic and mineralogical observations have led to the recognition of two stages of mineral formation. The first stage (retrograde metamorphism) is characterised by complete transformntion of magmatic olivine to lizardite and the second stage (prograde metamorphism) in the formation of antigorite and alteration of accessory chrome spinels. Mineral assemblages indicate serpentinization to be a low temperature oxidation phenomenon. Formation of magnetite, ferritchromit and sulphide minerals is controHed by oxygen and sulphur fugacities prevalent during the process of serpentinization. Mineralogy, chemistry and geological setting of the serpentinites indicate an isochemical nature of the serpentinization process.
A Lower Proterozoic Palaeosol at BGC-Aravalli Boundary in South-Central Rajasthan, India
Authors: Banerjee D. M.
Published: November 2024

A metamorphosed palaeosol surface separates the upper part of the Archaean Banded Gneissic complex from the basal Proterozoic Debari Formation of the Aravalli Supergroup. Mineralogical and petrological studies reflect presence of two mineralogical assemblages namely, quartz-feldspar-white mica-sericite-biotite-chlorite-calcite and quartz-kyanite-white mica-garnet. Geochemistry of the rocks collected along vertical profiles through the palaeosol units show high CIA indices in comparison to low CIA values of less altered basement gneisses. From bottom to the top, in the basement rocks as well as the palaeosol unit, a perceptible increase in Al2O3, SiO2, and TiO2, contents could be seen. Iron shows gradual upward increment in the assemblage-I while assemblage-2 contains very little iron. Na2O shows upward decrease while K2O shows quantum jump in abundance. K-Al correlation is strong and significant. Another iron-rich palaeosol unit is described between the basement gneisses and the Matoon dolomites. Based on the identification and characterization of the palaeosol units, the geological conditions prevailing before the onset of Aravalli sedimentation has been discussed. Diagenetic and metamorphic imprints on the palaeosols, now occuring as metamorphosed rock units have been defined and interpreted. This study has been utilised for reflecting the atmospheric conditions dominating during the early Proterozoic time.
Palaeocurrent Pattern, Textures and Depositional Environment of Miliolitic Limestone of Diu, Western India
Authors: Mahender Kotha
Published: November 2024

The present work deals with the palaeocurrent pattern and the textural attributes of the miliolitic limestone of Diu and their application for the interpretation of its origin and depositional mechanisms. The palaeocurrent pattern indicate a north to northeasterly direction of sediment transport which is similar to the present day wind pattern along Saurashtra coast. The limestone is fine to medium grained, moderate to better sorted, fine-skewed and leptokurtic to mesokurtic in nature. The study suggests a variable coastal marine beach to dune (eolian) environment of the limestone, representing the fluctuating sea levels of the Pleistocene Period. The constituent particles of the limestone. derived from the exposed beach and shallow-marine environments during lower sea levels, have been reworked by the prevailing wind and rain waters leading to limestone deposition.
Evaluation of REE Determination in Geological Samples by Inductively Coupled Plasma Emission Spectrometry
Authors: Rathi M. S. , Khanna P. P. , Mukherjee P. K. , Saini N. K.
Published: November 2024

Rare earth elements were separated from ten intemational geological reference samples by the classical ion-exchange chromatographic technique. Concentrations of ten rare earth elements were measured by inductively coupled plasma emission spectrometry. Comparison with the conensus values show a fairly good accuracy (<10%) for all the elements except for Lu. REE data for MB-H a metabasic reference sample and G-2, a granite reference sample have been compiled to determine the long term precision. A RSD value of 5-8% for La, Ce, Nd, Sm, Eu, Gd, Dy, Er and Yb indicates good reproducibility of our values. RSD for Lu was found to be high and it reaches up to 22% in G-2. The high RSD and poor accuracy for Lu in some samples is mainly attributed to low abundance level of this element which is very close to its detection limit. Ce, Gd and Sm are preferred to be analysed against a separated REE fraction of a rock standard having similar matrix to avoid the interferences. However, rest of the REEs can be comfortably measured against a salt standard.
Intra-Crustal Structure Inferred from Aeromagnetics in a Part of the Eastern Dharwar Craton and its Significance in Kimberlite Exploration
Authors: Atchuta Rao D.
Published: November 2024

Kimberlites, in addition to being the principal source of industrial and precious diamonds, also serve as windows into the earth's mantle. Therefore, their discovery has academic and economic importance. Power spectral analysis of the aeromagnetic data of a part of the Eastern Dharwar Craton, comprising the western part of the Cuddapah basin and the adjoining crystallines, has brought out upwarping (anticlise) and downwarping (syneclise) of intra-crustal magnetic interface. The known kimberlite diatremes at Wajrakarur and Chigicherla are principally concentrated in zones overlying the domal upwarps of the magnetic interface and these zones perhaps delineate two distinct kimberlite fields. Exploration in such zones (zones overlying upwarp of magnetic interface) is recommended for verifying the validity of the relationship and location of additional kimberlites.
Sedimentary Structures and Texture of the Warkalli Sandstone (Mio-Pliocene) at Cherunniyoor, Kerala
Authors: Padmalal D.
Published: November 2024

The Quarry at Cherunniyoor, 3 km east of the Varkala town exposes a section of Warkalli beds of Mio-Pliocence age. The Sedimentary structures like channel fills, cross bedding, lenticular bedding, convolute lamination, clay galls, water escape structure and trace fossils are noticed in the section. The Warkalli sandstone at Cherunniyoor is composed mainly of coarse to medium grained, poorly to moderately sorted, angular to subangular grains with platy-to-mcso-kurtosis and nearly symmetrical skewness. The sedimentary structures together with the textural characteristics as well as the fining upward nature of lithological units point to a fluvial (meandering river) origin for the sandstone and hence for the Warkalli beds at Cherunniyoor.
Biogeochemical Studies in Some Copper Rich Areas of Singhbhum Copper Belt, Bihar, India
Authors: Venu P. , Chand Gyan
Published: November 2024

Forty eight plant species (528 plant samples) from the Singhbhum copper belt were examined and their relationships with soil copper gradient were assessed. Syzygium cumini, Woodfordia fruticosa, Cleistanthus collinus and Buchanania lanzan are observed to grow in very high soil copper concentration maintaining remarkably moderate levels of copper in their bioparts. Results of Student's 't' test suggests that some species exhibit preferential concentration of copper in different bioparts. Copper levels estimated in Anogeissus latifolia, Butea frondosa, Cleistanthus collinus, Croton roxburghii, Syzygium cumini, Mitragyna parvifolia, Gardenia gummifera, Nyctanthes arbortristis. Shorea robusta and Terminalia crenulata showed significant relationships with that of soil copper. However, none of the plants examined can be graded as 'hyperaccumulators'or 'accumulators".
Influence of Geomorphometric Factors on Satellite Snow Covered Area vs Snowmelt Runoff Relationship in the Punjab Himalaya
Authors: Gupta R. P. , Sinha R. , Roohani M. S.
Published: November 2024

In the Himalayas, snowmelt runoff makes a dominant contribution to the total annllal stream flow. An early prediction of the amount of runoff to be derived from the snow pack is, therefore, of great importance for proper management of water resources. The area selected for the present investigation is the Punjab Himalayas comprising three major catchments of the Beas, Ravi, and Chenab rivers. Landsat imageries have been used to map snow cover in these three catchments. Data from a number of discharge gauging stations on the Beas, Ravi and Chenab rivers have been used to yield snowmelt runoff. Unique relationships between satellite snow cover and snowmelt runoff have been obtained for each of the sub-catchments. The studies show that geomorphometric parameters have a systematic influence on the relationship between snow cover area and subsequent runoff. The relationships are interpreted for their physical implications.
Chemistry of Clinopyroxenes from Subalkaline and Alkaline Rocks of Phenai Mata Igneous Complex, Baroda District, Gujarat, Western India
Authors: Kumar Santosh
Published: November 2024

The predominant tholeiitic gabbro-microgranite/granophyre suite has been found in close association with subordinate alkali gabbro-syenite suite at Phenai Mata Igneous Complex (PMIC) (65 Ma). The pyroxene compositions from the selected tholeiitic and alkaline lithotypes of PMIC have been classified and compared to those from alkaline rocks of adjoining complexes. The results indicate that pyroxenes were crystallized in diverse tholeiitic and alkaline parental magmas undergoing differential oxygen fugacity (fO2) and silica activity (aSiO2). The fractionation trend of pyroxenes from tholeiitic rocks of PMIC follows the trend transitional between Ca-poor and Ca-rich augite-ferroaugite trends, though limited iron-enrichment, formed under low fO2. Whereas pyroxenes in alkaline rocks follow the Ca-rich salite-ferrosalite trend at relatively higher fO2 and can be related to those of volcanic and subvolcanic alkaline rocks of adjacent alkaline complex probably representing an analogous alkaline pulse. The pyroxenes of alkaline rocks of PMIC and adjoining area can also be distinguished from those of tholeiitic rocks, having higher Ti and Al contents. An early and strong partitioning of Cr in crystallizing diopside, magnetite and probably chromspinel of tholeiitic and alkaline parental magmas impoverished the pyroxenes (Mg/Mg+Fe1<0.700) of microgranite and syenite in this element during the late stage of crystallization.
P-T Conditions of Metamorphism of Supracrustal Rocks in the Sandur Schist Belt, Dharwar Craton, Southern India
Authors: Hanuma Prasad M. , Krishna Rao B. , Vasudev V. N. , Basavalingu B.
Published: November 2024

Compositions of co-existing mineral pairs, viz., (a) cordierite- gedrite- garnet- biotite, (b) staurolite-biotite-garnet-muscovite-chlorite and (c) andalusite-staurolite-biotite-gamet in metapelites, and (d) amphibole-plagioclase pair in metabasalts of the Sandur schist belt in the eastern block of the Dharwar craton, Southern India, yield metamorphic temperatures and pressures in the range of 550°-600° C and 4-5.2 kbar, respectively. Textural relationships of the minerals in the above mineral assemblages suggest the development of cordierite, gedrite, garnet, staurolite and biotite during the main-fabric forming event (regional metamorphism). Increase in the grade of metamorphism from greenschist to amphibolite facies associated with the main deformational event is observed from the central to the peripheral portions of the belt; this can be attributed to the steep thermal gradient produced by the syntectonic granitoids. Andalusite post-dates all the other metamorphic minerals and its development outlasts the main deformational episode in the belt. Andalu~ite is a product of thermal metamorphism, superimposed on regional metamorphism and its growth coincides with the upliftment of the terrain during the emplacement of Iate- to post-kinematic granitoids, which, under comparatively low pressure regime (~3.75 kbar), maintained earlier peak metamorphic temperatures.
Termite Mound as a Biogeochemical Tool for Mineral Exploration : An Example from the Mangampeta Barite Mining Area, Cuddapah District, Andhra Pradesh
Authors: Raghu V. , Prasad E. A. V.
Published: November 2024

In the Mangampeta barite mining area, physical (organic matter and bulk density) and physico-chemical (pH and electrical conductivity) properties, and the concentration of trace elements viz., Ba, Sr, Cu, Zn, and Mn were determined for three types of termite mounds viz., barren (devoid of any vegetation), monophytic (colonised by a single plant species), and polyphytic (colonised by more than one plant species) and their adjoining ground surface soils.

A biogeochemical parameter called "Biological Absorption Coefficient" (BAC) [ratio of concentration of the element in the termite mound (C18) to that of its adjoining soils (C88)] of these mounds is computed which helps in the evaluatioo of the mounds in biogeochemical orientation surveys. These studies reveal that the mounds exhibit indicator characteristics for Ba, Cu, Zn, and Mn for use as tool in mineral exploration.
Insolubility and Volatilization of Elements in Biogeochemical Analysis of Soils and Termite Soils
Authors: Jayarama Gupta M. , Prasad E. A. V.
Published: November 2024

In order to study the biogeochemical interactions under the influence of organic matter, seven elements, namely Fe, Mn, Pb, Zn, Cu, Ni and Co, in termite soils and their adjoining ground surface soils of Ramagiri goldfield were analysed on both ash weight and dry weight bases.

A biogeochemical parameter, called "coefficient of apparent organic binding (CAOB)", is computed as the ratio of the concentration of an element in ignited sample and of the same element in dried sample. The variations in this parameter are due to insolubility of certain elements in the digested medium and volatilization of certain others on ashing.

The elemental concentration estimated on ash weight basis was converted into dry weight basis by recalculation taking organic matter into consideration. On this basis different degrees of insolubility or volatilization of different elements have been estimated.
Quaternary Geology and Geomorphology of a Part of Ghaghara-Rapti-Gandak Sub-Basins of Indogangetic Plain, Uttar Pradesh
Authors: Dwivedi G. N. , Sharma S. K. , Prasad Surendra , Rai R. P.
Published: November 2024

The Quaternary sediments of the Indogangetic plain in eastern part of Uttar Pradesh, can broadly be subdivided into two groups lithostratigraphically, viz. the Older Alluvium and the Newer Alluvium. The former is subdivided into basal Banda Older Alluvium (BOA) comprising of variegated clays and clastic sediments of Chitrakoot Formation encountered in the boreholes in the southern part and its equivalent Upper Siwalik in the northern part and an upper Varanasi Older Alluvium (VOA) and Palaeo Bhur deposits. The Newer Alluvium includes Bhat Alluvium, GhagharalRapti/GandakiChhoti GandaklChhoti Sarju Terrace Alluvium and their Recent Alluvia. The lithounits correspond to two broad geomorphic units, viz. an upland - the Bhangar surface and a low lying area demarcating the flood plains - the Khadar surface. The former consists of a piedmont zone of alluvial fans and an alluvial plain. while the later consists of terraced valley. The evolutionary history of Quaternary sedimentation commenced with a change in the configuration of Middle Siwalik basin converting it into much wider one by transgressing southward further over Bundelkhand gneissic complex and Vindhyan basement probably, during Upper PliocenelLower Pleistocene with sediment supply in the southern part from the Peninsular provenance constituting the Banda Older Alluvium and with sediments derived from Himalaya in northern part of the basin to constitute the Upper Siwalik. This was followed by a break in sedimentation caused due to upliftment during Middle Pleistocene resulting in a new basin formation superimposed over previous one, with sediment influx from the north, to the deposition of Varanasi Older Alluvium. The Upper Pleistocene glaciation brought an end to this sedimentation phase. The gradual warming up and retreat of glaciers accompanied with a large amount of sediment supply led to the formation of Bhat Alluvium in piedmont zone. A number of fluvial regimes, namely Ghaghara, Rapti, Gandak etc. carved out their new, narrow basins with warming up and increased precipitation during Holocene represented by their terraces. The ongoing phase of sedimentation is restricted to within the present active flood plain in response to reduced discharge and sediment supply.
Review of Precambrian Porphyry Cu ± Mo ± Au Deposits With Special Reference to Malanjkhand Porphyry Copper Deposit, Madhya Pradesh, India
Authors: Sikka Deshbandhu , Nehru C. E.
Published: November 2024

Precambrian porphyry type Cu±Mo±Au deposits are present in many parts of the world including Australia, Brazil, Canada, China, Finland, India, Namibia, Russia, Sweden, and Zambia. Most of them are associated with calc-alkaline or alkaline subduction zone volcanics or granitoids of the I-type. Precambrian deposits range in age from 33l4±6 Ma to 561±9 Ma. The majority of the deposits fall into four age groupings with peaks around 3300±100Ma, 2700±100Ma, 1900±100 Ma. and 1100 ± 100 Ma which are indicative of major tectonic and magmatic episodes in different parts of the world. Precambrian deposits have many similarities with the younger porphyry copper deposits in the Phanerozoic. Some outstanding examples include Malanjkhand deposit (789 Mt x 0.83% Cu; 0.004% Mo: 0.2 gm/T Au; 6 gm/T Ag) and Tongkuangyu, China (380 Mt x 0.67% Cu) are in production. The Troilus Lake deposit, Quebec, Canada (42.9 Mt x 0.12% Cu; 1.4 gm/t Au; 1.4 gm/ t Ag) and Haib River, Namibia (600 Mt x 0.3% Cu) are being considered for exploitation.

After a review of the salient features of porphyry Cu±Mo±Au deposits in general and those of the Precambrian porphyry Cu±Mo±Au age in particular, it is suggested that Precambrian terrains should be good targets for exploration.
Lithostratigraphy and Hydrocarbon Prospects of the Olpad Formation of Paleocene-Early Eocene Age in Ahmedabad-Mehsana Tectonic Block, Cambay Basin
Authors: Samanta M. K. , Gavarshetty C. P. , Kumar Ashish
Published: November 2024

The Olpad Formation of Paleocene-Early Eocene age represents the oldest Tertiary clastic deposits. in the Mehsana area, North Cambay Basin. This unit is characterised by its heterogeneous lithologic association of volcanic conglomerate, volcanic wacke, trapwash, siltstone and shale, deposited by alluvial fan systems along fringes of palaeohighs and lacustrine to brakish water condition in the existing palaeolows. Recent exploratory drilling proved the occurrence of hydrocarbons in this formation. This significant find has prompted the necessity of identifying potential hydrocarbon reservoirs. The formation has been subdivided into three lithostratigraphic units (Unit I - III in descending order) based on sedimentary facies and well log characteristics. The reservoir characteristics of the sediments of Olpad Formation has been worked out based on sedimentological, SEM and XRD studies.

Lithostratigraphic correlation, structural configuration and thickness variation have been discussed. The study reveals that the distribution of different lithostratigraphic unit is controlled by tectono-sedimentation factors and the volcanic wacke lithofacies of Unit-I and III constitute the reservoir rock in the Olpad Fonnation. The study led to the identification of Umiwa. Khambel and Gamanpura as prospective areas for future exploration for structural-cum-stratigraphic traps.
Aseismicity of the Andaman Subduction Zone and Recent Volcanism
Authors: Dasgupta Sujit , Mukhopadhyay Manoj
Published: November 2024

The Barren Island volcano in central Andaman Sea erupted afresh on March 29, 1991, since its last eruptions in 1789 and 1832. Tectonic framework of the Barren Island volcano is delineated by a set of seismically mapped faults, including the West Andaman Fault, which. connects to the Semangko Fault in Sumatra. The morphology of Andaman Benioff zone as seen on a vertical section reveals a seismic gap at 90-110 km depth. Spatially it relates to the zone of current volcanism of the Barren and its neighbouring Alcock Seamount in a structurally depressed area. The seismic gap in the Benioff zone is interpreted as a zone of partial melting in the descending Indian Ocean lithosphere which prevents stress accumulation owing to the decreased viscosity. Best double couple solutions for the Barren Island earthquakes of October 10 and December 25, 1990, which preceded the volcanism suggest that rupturing through normal dip-slip faulting prevailed in the overriding Burma plate prior to the recent volcanism. Pronounced back-arc seismicity at shallower depths is seen further to the east and southeast of the Alcock Seamount; this relates to back-arc rifting under the Andaman Sea.
Carbon Isotope Thermometry in Marbles of Ambasamudram, Kerala Khondalite Belt, Southern India
Authors: Satish Kumar M. , Santosh M. , Wada H.
Published: November 2024

Calcite-graphite isotope exchange thermometer is a useful tool in elucidating the peak metamorphic temperatures in regionally metamorphosed marbles, for which normal cation exchange thermometers are not available.
Geothermometric and Oxygen Fugacity Studies of Mayurbhanj Basic Igneous Complex
Authors: Das S. K. , Mukherji S.
Published: November 2024

The basic igneous complex of Mayurbhanj is a differentiated suite composed of harzburgite, gabbronorite, leucogabbronorite and anorthosite. EPMA of the coexisting oxides in the rock samples reveal that magnetite-ilmenite have re-equilibrated between 770°C and less than 500°C and fo2, of 10-16 to less than 10-25. Ilmenite granules and thick lamellae have identical composition and approach pure FeTiO3. The chrominn spinel-olivine geothermometry in harzburgite suggests a temperature of 1263°C. The pyroxene geothermometric data in gabbroic rocks indicate equilibration temperature range of 819° C to 1071° C. The thermometric data indicate that the magnetite and ilmenite equilibrated at lower temperature than the coexisting pyroxenes for a particular rock sample.
Isotopic Signature of Pan-African Rejuvenation in the Kerala Khondalite Belt, Southern India: Implications for East Gondwana Reassembly
Authors: Unnikrishnan-Warrier C.
Published: November 2024

Sm-Nd isotope systematics on mineral separates from sillimanite-and cordierite-bearing metapelite (khondalite), and garnet-and biotite-bearing gneiss (leptynite) from the Kerala Khondalite Belt (KKB), southern India, yielded mineral isochron ages (wr-feld-bio-gar) of 537 ± 27 Ma (MSWD = 0.9) and 534 ± 26 Ma (MSWD = 1.23) respectively. Rb-Sr systematics in the same samples gave wr-feld-bio mineral isochron ages of 437 ± 9 Ma (MSWD = 0.67) and 467 ± 9 Ma (MSWD = 0.76), These results provide the first mineral isochron ages for the regional metasedimentaries in the KKB. The e (Nd T) values at 550 Ma for Khondalite and leptynite are -22.7 and -21.8 respectively. These results demonstrate a complete rejuvenation of the crust during Pan-African times. Coeval alkaline plutons emplaced along fault-lineaments in this area suggest an extensional tectonic regime. Geochronologic correlations with the Lutzow-Holm Bay Complexes in East Antarctica, and the Highland and Southwestern Complex of Sri Lanka show that a similar Pan-African tectonothermal event manifested in all the East Gondwana crustal fragments.
Fossil Wood in Tertiary Cuddalore Sandstones near Tiruvakkarai, South Arcot District, Tamil Nadu
Authors: Subramanian K. S. , Renganathan M. , Kanishkan B.
Published: November 2024

In the CuddaIore sandstones of Mio-Pliocene age in the east coast of Tamil Nadu, the lignite horizon in Neyve1i is succeeded by pebbly sandstones with petrified tree trunks in Tiruvakkarai. Obviously, fluctuations in climate during Mio-Pliocene gave rise to different environments of deposition of sediments and vegetal matter, resulting in the carbonisation of vegetal matter in Neyveli and siliceous petrification of tree trunks in Tiruvakkarai.
Textural Parameters, Discriminant Analysis and Depositional Environments of the Tcri sands, Southern Tamil Nadu
Authors: Joseph Sabu , Thrivikramaji K. P. , Anirudhan S.
Published: November 2024

Results of analysis of size data by frequency curves and multi-group discriminat analysis (MGDA) indicate that inland Teri Deposits (ITDs) are very much similar to colluvium, formed by mass-wasting and fluvial processes, whereas Coastal Teri Deposits (CTDs) Very likely originated in mixed environments i.e., beach and dune. further, it is proposed that the ancestral sediments of present day CTDs would have originated from the vast reservoir of shelf sand that remained subaerially exposed during the low sea leval stands which coincided with Late Pleistocene glaciation.
Basin Evolution Study of the Machundri River, Southern Saurashtra Coast, Gujarat
Authors: Rakshit Prabal , Sinha A. K.
Published: November 2024

The Neogene/Quaternary boundary is reported to be erosional. The Pleistocene miliolite limestone shows the development of a sequence of palaeo-beach-dune complexes with the gradual fall of sea level. The late Pleistocene-Holocene stratigraphic units comprise different generations of deltaic sediments aggrading older tidal marshes and backswarnps. The late Holocene sea-level fall helped in delta progradation and the development of different accretionary units all along the coast.
Occurrence of Rare Earth Elements in Panchpatmali Bauxite Deposit and Red Mud, Koraput District, Orissa
Authors: Subrahmanyam A. V. , Singh Jagmer
Published: November 2024

The geochemistry reveals LREE enrichment, high degree of fractionation, positive Ce anomalies and negative Eu anomalies in the samples. Red mud contains 18 to 29% of heavy minerals; and thus the red mud could be an alternative source to beach sands.
Petrology and Geochemistry of the Granitoids of Central Gneissic Complex in the Kameng district, Arunachal Pradesh
Authors: Dikshitulu G. R. , Dhana Raju R.
Published: November 2024

Petrology and geochemistry (major, minor and trace elements including REE) of the different granitoids from Central Gnessic Complex indicate that, (a) the dominant Palaeoproterozoic migmatite, hornblende granite gneiss, two-mica granite and augen gneiss are syn-kinematic, autochthonous, peraluminous, low-Ca granodiorite, with the first three being of S-type formed by highdegree (>50%) anatexis of sediments of psammopelitic composition, whereas the augen gneiss is I-type formed by partial melting of a basic rock of mantle affinity coupled with notable crustal contamination and affected by soda metasomatism; (b) the minor Mesoproterozoic Salari granite is late-kinematic, allochthonous, metaaluminous, epidote-bearing, high-Ca monzogranite of I-type formed by partial melting of basic rock from crustal depth; (c) the youngest (ca. 30 Ma) tourmaline granite is post-kinematic, allochthonous, strongly peraluminous, high-level syenogranite of S-type, with its parental melt derived from a peraluminous granitoid by anatexis induced by large volume of volatiles and fluids, and (d) tectonically, these granitoids are of 'syn-collision' type.
Recognition of Paleo Pennar Delta: Assessment of Aquifer Parameters and Environmental Constraints
Authors: Radhakrishna I.
Published: November 2024

A fan-shaped paleodelta existed during Quaternary period with buildup of paleochannels along major lil1eament~. This paleodelta region is characterised by thick fluviatile granular sediments, low electrical conductivity and chloride levels. Ground water flow paths, subsurface aquifer geometry and transmissivity trends for paleo Pennar delta region are presented and discussed.
Structural Appraisal of Parts of Archaeans, Satpuras and Chhattisgarh Basins Around Mandala - Raipur Districts, M.P., India, Using Total Magnetic Field Data
Authors: Singh V. P. , Singh O. P. , Singh C. L.
Published: November 2024

Detailed ground magnetic surveys over parts of Archaeans. Satpuras and Chhattisgarh basins belonging to different ages around Mandala-Raipur has been carried out. Detailed investigations provide depth of magnetic sources, basement structural trend. nature of intrusive bodies and thickness of sediments in the basins. The basement structural trend along the five profiles in Archaeans (AA'and BB'), Satpuras (CC') and Chhattisgarh (DD' and EE') have been derived which ranges from 1.5 to 3.5 km. The Archaean and Chattisgarh basins show two dyke like features at depth of 0.28 and 1.26 km. It also reflects upwarping of the basement along the profiles.
A Record of Algal Oncolites of Lower Permian Age in Cauvery Basin, Tamil Nadu, India
Authors: Yadagiri K. , Govindan A.
Published: November 2024

A conventional core abstracted above the basement in an exploratory well PUNDI-A in the western part of Tanjore sub-basin, indicated the presence of algal oncolites of Lower Permian age inferred from palynofloral assemblage in the under/overlying Shales.
A Laboratory Study of the Flocculation of Dissolved Heavy Metals in Kali RiverDuring Estuarine Mixing, West Coast of India
Authors: Balakrishna K. , Manjunatha B. R. , Shankar R.
Published: November 2024

River water-sea water mixing experiments were carried out to study the time dependence of flocculation process, the flocculation behaviour of dissolved Cu, Pb, Zn, Ni, Co, Mn, Cr and Fe in the Kali estuary. Flocculation appears to be maximum at high salinities (>25‰) and is rapid, about 7 to 60% of the dissolved metal content flocculating within half an hour of mixing. This brings out the role of sea water as a powerful flocculating agent for the dissolved load of river water.
Subaqueous-Dune in the Miliolite Limestone of Saurashtra, India
Authors: Gharia S. S.
Published: November 2024

This paper describes the occurrence of sedimentary structures characteristic of shallow-marine environment, dominated by tidal currents occasionally superimposed by storm and windinduced currents in the Miliolite limestone of Saurashtra.
Elemental Chemistry of Ilmenite - An Indicator of Provenance?
Authors: Bhattacharyya Samit , Sengupta Ranadhir , Chakraborty Manas
Published: November 2024

Elemental chemistry of ilmenite has been determined with a view to studying the applicability of the parameter in determination of provenance of the placer minerals. While the values of Mn/Mg ratio conform to the already determined provenance of the east coast occurrence, the west coast ilmenites have lower values for this ratio suggesting a basic rock dominated provenance rather than chamockite/khondalite/migmatitic source. Present study recommends a fresh look at provenance study of the west coast placers vis-a-vis examination of applicability of Mn/Mg values of ilmenite in relation to the provenance.
Stratigraphy and Tectonic Setting of the Trans-Aravalli Neoproterozoic Volcanosedimentary Sequences in Rajasthan
Authors: Chore S. A. , Mohanty M.
Published: November 2024

At least three formations in Punagarh Group and two in Sindreth Group are identifiable on the basis of varied lithoassemblages. The geochemical parametres of the mafic (mainly pillowed) and felsic volcanics suggest that their effusion is linked to the deep seated fractures responsible for the formation of intracratonic grabens. The association of bimodal volcanics and coarse clastics in linear grabens suggest the development of retroarc basins as a consequence of subduction of South Delhi Oceanic-transitional crust under the western Marwar continental crust. The Trans-Aravalli region in Rajasthan contains Neoproterozoic sequences of Punagarh and Sindreth groups occurring in isolated linear basins.
Conditions of Metamorphism of the Garnet-Cordierite Gneisses from Malai Mahadeswara Hills, South India and the Origin of Zn-Cr-Rich Spinel
Authors: Fonarev V. I. , Janardhan A. S. , Konilov A. N.
Published: November 2024

A spinel phase with unusually high ZnO (8.8-11.0) and Cr2O3 (13.2-15.8%) contents is found in garnet-cordierite-sillimanite bearing migmatised pelitic bands interbedded with tonalitic charnockites of Malai Mahadeswara (MM) Hills. The textural and microprobe data indicate that this spinel phase is associated with late iron-rich garnet (rim)-cordierite-sillimanite assemblage.

P-T conditions of cordierite-garnet assemblages vary from peak metamorphic conditions of greater than 8 kbar and 750°C to 6.7±1.4 kbar and 685 ±20°C. The last retrograde phase of metamorphism took place at P of 4.5 kbar and at T of 580°C. The formation of Zn and Cr rich spinel phase must have taken place during this waning stages of metamorphism by the activity of hydrothermal fluids.
On the Intrusive Suite from Biharpur, Madhya Pradesh
Authors: Ghosh Kaushik K. , Ray Jyotisankar , Nandy Keya
Published: November 2024

The intrusive suite comprises gabbro, dolerite (with hornblende-bearing variant), diorite and granitoids with both porphyritic and non-porphyritic types. A calc-alkaline character, on the acid intrusives is evident. Genetic link amongst the gabbro-dolerite-diorite intrusive members is suggested. The granitoid intrusives, on the other hand. appear to have no direct genetic lineage.
Petrology of the Proterozoic Alkaline Carbonatite Complex of Samalpatti, District Dharmapuri, Tamil Nadu
Authors: Srivastava Rajesh K.
Published: November 2024

The gneissic rocks of Samalpatti area are intruded by the Proterozoic carbonatites, alkaline rocks, pyroxenites and minor dunites. Mineralogically carbonatites show wide variations in their composition but chemically most of them are silico-carbonatites. Presence of hornfelsic textures and metamorphic minerals like chlorite, scapolite, diopside and grossularite, suggest metamorphism of the present carbonatites. Alkaline rocks are either syenites or lamprophyres. Both carbonatites and alkaline rocks are generally enriched in large-ion lithophile elements (LILE) and high-field strength elements (HFSE) relative to the primordial mantle. Although carbonatite samples have lower concentration of LILE and HFSE than the average values of known carbonatites, they fall within the range of magmatic carbonatite concentrations. Lower concentrations of these elements are a result of hydrothermal metamorphism by hot fluids.

Carbonatites are also enriched in d13C and d18O-values. The Rayleigh fractionation together with post-magmatic secondary processes, particularly exchange with magmatic fluids of high d18O content, are the best explanation for the C and 0 isotope enrichments. The carbonatites and alkaline rocks have probably crystallized from the carbonate and silicate melts separated from a postulated carbonated nephelinitic magma by Iiquid immiscibility at shallow levels.
FTIR Study of Lower Gondwana Coal from Talcher, Orissa
Authors: Misra S. K. , Mohanty J. K. , Nanda B.
Published: November 2024

Functional groups and mineral matters in Talcher coal have been identified with the help of FTIR. Oxygen bearing functional group mostly hydroxyl is common in bulk as well as different lithotypes. Minerals such as kaolinite, quartz, goethite etc. have been identified from the spectra. The functional groups data have been used to interpret the conditions of formation of the different lithotypes.
Kyanite-Phlogopite-Clinochlore Association in the Pelitic Rocks of the Vaikrita Group and the Haimanta Formation, Satluj Valley, Himachal Himalayas
Authors: Vir Pushpendra , Misra Jai K. , Mukhopadhyay Dilip K.
Published: November 2024

We report an unusual association of kyanite-phlogopite-clinochlore from the psammo-pelitic rocks occurring in the Higher Himalayas along the Satluj river between Shongtong and Morang, Himachal Pradesh. These rocks supposedly belong to the Vaikrita Group and the Haimanta Formation.
Co-Existing Pyroxenes from the Ferrosyenites of Sivamaiai, Tamil Nadu, South India
Authors: Ratnakar J. , Leelanandam C.
Published: November 2024

The ferrosyenites of Sivamalai (Tamil Nadu, South India) contains ortho- and clinopyroxenes in addition to fayalitic olivine, quartz, palgioclase, orthoclase perthite and opaques. The orthopyroxene occurs as (a) submicroscopic rim around fayalite, (b) exsolved (001) and (100) lamellae within clinopyroxene and (c) discrete blebs close to clinopyroxene. The composition of orthopyroxene among the analysed samples varies from eulite to orthoferrosilite and that of clinopyroxene from ferroaugite to ferrohedenbergite. The ortho- and clinopyroxenes individually exhibit systematic intraspecimen and intralintergranular variations of Fe and Mg, with a restricted range of Ca. The Fe/(Fe+Mg) ratios in the pyroxenes (0.966-0.722) indicate their consistency iron-rich nature, and the orthopyroxenes, in particular. are among a few extremely iron-rich ones reported.

The occurrence of orthopyroxene lamellae within clinopyroxenes of ferrosyenites of Sivamalai is a diagnostic feature of slow cooling of a tholeiitic magma. The two compositional trends defined by the pyroxenes in the quadrilateral suggest strongly fractionated nature of the liquid. The mineral assemblage fayalite+quartz+ferrosilite-rich orthopyroxene suggests a minimum P of 6 kb. The Sivamalai pyroxenes are considered to have formed at -740°C and 7 kb. These pyroxenes are presumably crystalllized from a Fe-rich acidic liquid under low fO2, moderate to high P and increasing SiO2.
Characteristics of Manganite (?-MnOOH) in Manganese-Rich Gangpur Group of Rocks, Orissa
Authors: Mohapatra B. K. , Nayak B. R.
Published: November 2024

Manganite ?-MnOOH, in the manganese-rich rocks of Precambrian Gangpur Group, Sundargarh district, Orissa, shows dissimilar fabrics and belongs to three generations but has more or less similar chemical composition. It occurs as patchy inclusions, accicular crystallites, egg-shaped micro-nodules, medium to coarse-grained mosaics, vein and fissure fillings and as wedge-shaped linings. The manganite is either formed froin Mn-oxide (jacobsite and vredenburgite) phases through retrogressive metamorphic transformation (Ma1) or generated through pseudomorphic replacement of Mn-sillicate (rhodonite and tcphroite) or Mn-carbonate (rhodochrosite) by chemical weathering under supergene conditions (Ma2). The vein filling type is the latest in its paragenesis (Ma3). Despite different mineral lineages, manganites are chemically similar though crystallites located in veins and fissures are relatively pure.
Planktic Foraminiferal Biostratigraphy and Biochronology of the Post-Miogypsina Neogene of Bombay Offshore Basin
Authors: Dave Alok
Published: November 2024

Neogene planktic foraminiferal events and biostratigraphy of four deep well sections viz. D1-A-1, SS-1, R-13-1 and D-4-1 in the Bombay Offshore Basin have been established. A pronounced and regiona lunconformity separates the post-Miogypsina (post Zone N10 or N12, Middle Miocene) clay/claystone succession from the underlying carbonates. In most of the studied wells the hiatus covers a time span of 6.5 Ma (or 9.7 Ma) involving part of Middle Miocene and entire Late Miocene except in well D-4-1 where its span is greatly reduced. Three planktic foraminiferal datums viz. LAD of Globigerina nepenthes (3.78 Ma), LAD of Dentoglobigerina altispira (2.6 Ma) and LAD of Globigerinoides fistulosus (1.6 Ma) have been demarcated in the Pliocene. A comparison of these biochronologic datums with those recorded from the DSDP sites in northern Indian Ocean is made. The delayed Last Occurrence of Globoquadrina dehiscens in Bombay Offshore is attributed to its reworking in Pliocene.
Stratigraphy and Palichnology of Nimar Sandstone, Bagh Beds of Jobat Area, Jhabua District, Madhya Pradesh
Authors: Kundal P. , Sanganwar B. N.
Published: November 2024

Medium to fine grained Nimar Sandstone has yielded abundant ichnofossils comprising sixteen ichnospecies shared among eleven ichnogenera. These are: Annetuba chapdiensis, Cylindrichnus sp., Granularia yelamensis, Gyrochorte comosa, Imponoglyphus kevadiensis, Keckia annulata, Laevicyclus mongraensis, Palaeophycus heberti, P. intermediatus, P. tubularis, Planolites annularis, P. beverleyensis, P. montanus, Rosselia socialis, Thalassinoides paradoxicus and T. suevicus. Five species, namely, Planolites annularis. P. beverleyensis, Rosselia socialist Thalassinoides paradoxicus and T. suevicus are new additions to our knowledge of the ichnofauna of the Bagh Beds. Palaeophycus intermediatus is the solitary ichnospecies described herein as new.
Incipient Diapirism Coeval to Bhuban Sedimentation: A New Hydrocarbon Exploration Play in Cachar Fold Belt, Assam
Authors: Palakshi K. , Rao C. G. , Ramprasad B. P. , Subrahmanyam D.
Published: November 2024

Reflection seismic facies analysis pertaining to southern part of Katakhal syncline, Cachar Fold Belt, Assam, has brought out an anomalous zone of chaotic reflections bounded by high amplitude, continuous, correlatable reflection events. This anomalous zone displays an elliptical shape in plan view and is aligned with the associated folds. The genesis of this anomaly, developed along the eastern flank of the syncline, bracing the synclinal axis is assigned to the non piercement type of shale diapirism within Middle Bhuban Formation of Middle Miocene age. The geological model envisaged has further led to the delineation of supra and lateral diapiric traps in the overlying Upper Bhuban and Bokabil Formations of Mio-Pliocene age. The reconstruction of structural evolution has brought out a phase of inversion during Plio-Pleistocene where the anticlines within Miocene and Mia-Pliocene sequences turned into synclines. The delineated supra and lateral diapiric traps have not been obliterated during inversion episodes. The identified prospects are new type of plays to be tested in Cachar Fold Belt, and form a step forward in focusing the thrust areas of exploration on the gentler synclinal flanks
Record of Well Preserved Trilobites from the Cambrian of Zanskar
Authors: Kumar Ashok
Published: November 2024

Trilobites are important fossils ranging from Cambrian to Permian in age while they are stratigraphically significant in the Lower Palaeozoic. Well preserved trilobites discovered from the Kurgiakh area of the Kunzam La Formation of Zanskar Basin including Ptychoparia consocialis, P. pervulgata, Ptychoparia sp., Lyriaspis spitiensis, Lyriaspis sp., Anomocarella resseri, Anomocaraspis hundwarense. Anomocare sp., Hundwarella transversa, Hundwarella cf. convexa, Hundwarella personata, Hundwarella sp., Elrathia cf. chuwansis, Eymekops hermias. Lisania sp., Damesella sp., Lorenzella sp. Yuehsienszella sp. are reported.
Mudbank Dynamics: Physical Properties of Sediments
Authors: Manoj Kumar P. , Narayana A. C. , Tatavarti R.
Published: November 2024

Surface sediment particle sizes, their spatial distribution and their geotechnical characteristics in the Ambalapuzha-Purakkad Mudbank were studied, based on field observations during pre-monsoon and monsoon seasons. The study revealed that sediments in the mudbank are clayey silts in both the seasons. The magnitude of the fine silt and clay contents blanketing the ocean bed were however, observed to be more in the pre-monsoon season indicating the possibility of fine silt and clay going into suspension during the monsoon season. Geotechnical properties of surface sediments revealed that they are highly plastic, with high liquid limits. Organic carbon, fine silt and clay minerals play an important role in the behaviour of mudbank sediments.
Petrography and Geochemistry of the Mesozoic Granite at Mashhad, Khorasan Province, Northeastern Part of Iran
Authors: Iranmanesh Jalil , Sethna S. F.
Published: November 2024

A petrographic and geochemical study of the Mashhad granite in the northeastern part of I.R. Iran reveals that it is of two main varieties - the major body of S-Type continental collisionlsyncollision biotite/muscovite granite and pegmatites; the other of I-Type, Mthin plate/post collision uplift - homblende-hedenbergite/green biotite granite with the latter intrusive into the former. The homblendehedenbergite-compared to the biotite-granite, shows appreciable enrichment in the high field strength (HFS) and rare earth elements. One peculiar character in these granites is the negative correlation of Si02 and distinct positive correlation of CaO against the HFS and RE elements, and the latter character is attributed to the presence of large amounts of sphene and apatite in the homblende-hedenbergite granite.
Airborne Magnetic Lineament, Groundwater Potentiality and Basement Structures in S-E Part of Vindhyan Basin
Authors: Mishra D. C. , Gupta S. B. , Prabhakar Rao M. R. K.
Published: November 2024

Airborne total intensity magnetic survey flown at a height of approximately 152 m in central India has delineated several linear magnetic anomalies of 200-400 nT aligned together to form a large magnetic lineament approximately 1 km wide and 100 km long. The nature of magnetic anomalies suggest the lineament to be a fracture zone with basic intrusives at places. Magnetic and resistivity surveys on ground provide large magnetic (600-800 nT) and low resistivity anomalies along this lineament suggesting a fracture zone with basic intrusive rocks at places and very good groundwater potentiality along it.. Existing wells close to the lineament yield good amount of water, while those away from it show poor yield. Water table contour map of the area shows contours parallel to the lineament indicating pumping of more water from this zone causing lateral flow of groundwater.

This lineament does not find reflection in the ground gravity survey; instead it delineated some second order small dome and basin structures around Damoh and Jabera which are not recorded in the airborne total intensity map referred to above. This suggests that while linear features are better reflected in the airborne magnetic surveys small-scale three-dimensional basement structures are better reflected in the ground gravity surveys. This indicates the need for an integrated airborne and ground exploration programme for delineating subsurface structures/tectonics and to quickly assess the groundwater resources of a region.
Electron Microprobe Dating of Monazite from Spinel Granulite in the Eastern Ghats Belt, India
Authors: Rao A. T. , Fonarev V. I. , Konilov A. N. , Romanenko M.
Published: November 2024

Electron microprobe dating method is same as chemical aging method of U-Th minerals used in geochronology. The Th-U-Pb concentrations obtained from a single electron probe analysis allow calculation of geologically meaningful age. Based on this method monazite from spinel granulite of Visakhapatnam in the Eastern Ghats Belt (EGB) gave ~1,000 Ma, corroborating the late Proterozoic metamorphism and charnockite emplacement, established in parts of the EGB and Antarctica. Microgeochronology of commonly occurring accessory mineral such as monazite in granulite variants is recommended for quick reconnaissance correlation in Gondwanian fragments in East Gondwanaland.
Estimation of Parameters of an Extensive Aquifer - A Case Study
Authors: Thangarajan M. , Singh V. S.
Published: November 2024

With the growing needs of water, particularly in developing countries, groundwater resources are being exploited indiscriminately. Evolution of pumping schemes for the development of groundwater resources has become an imperative need to minimise the environmental hazards. This, in turn, requires a reliable estimation of hydrogeological parameters and quantitative appraisal of interference between wells. Pumping tests using a distributed battery of wells may give a representative estimate of aquifer parameters valid over a large area.

One such study was carried out in the Neyveli basin, Tamil Nadu (India), using pumping test data on wells distributed over a total distance of about 2 km. The spread of observation wells was about 4 km. The pumping was continued till a steady state condition was achieved which was monitored through continuous recording of water levels in the observation wells. The drawdowns at any observation point due to pumping of a number of wells is calculated using the principle of superposition. Forward modelling has been employed for the estimation of aquifer parameters through comparison of computed and observed drawdowns. This approach, besides enabling estimation of hydrogeological parameters, can also provide a first-order basis to design an optimal spatial pattern of wells and pumping rate to achieve a specified drawdown in a certain area.