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Papers by rajkumar p

Coastal areas, the place where the water of the sea meet the land are indeed unique places in our... more Coastal areas, the place where the water of the sea meet the land are indeed unique places in our global geography. Coastal zones are dynamic interfaces between land and water and are common locations of high-density development. Monitoring shoreline changes help to identify the nature and processes that caused these changes in any specific area, to assess the human impact and to plan management strategies. Remote sensing data could be used effectively to monitor the changes along the coastal zone, including shoreline with reasonable accuracy it has been taken up. The study area is the district of Pondicherry, which is the first largest among the four regions ,and it has an area of 293 km 2 .The study area falls in the Survey of India Topographic Map nos. of 58M/13 and 58P/16 on 1:50,000 scale. Detailed geomorphological was done based on mapping has been done using IRS P5 (2011) data and Survey of India Topographic map. In the present study, detailed coastal geomorphologic landforms of fluvial, coastal and uplands were studied.

Coal fines production and structural collapse during waterflooding process was widely observed an... more Coal fines production and structural collapse during waterflooding process was widely observed and reported in several coalbed methane (CBM) fields. Besides, fines migration also plays a major role in the destruction of coal cleats and consequently, declining the gas recovery. This paper presents the coal fines production in lignite core as a function of kaolinite. Actually, it is a clay fine particle that rests on coal surface under the dominances of the four forces, namely, lift, drag, gravity, and electrostatics. Under hydrodynamic and thermodynamic forces these fines detach from the rock surface and migrate in the porous interspace, and at a certain point it is captured, and thereby deteriorating the well productivity and structural collapse as well. Many researchers have investigated these fines migration mechanisms in anthracite and bituminous coals, but to best of our knowledge till date this research was not carried out in lignite coals. In order to successfully demonstrate this mechanism in lignite, three sets of coreflood experiments have been conducted under ambient conditions for analyzing the coal and kaolinite fines transport and their impact on gas recovery. Lignite samples are procured from Neyveli Mines at Cauvery Basin in Southern India and then the simulated version is used for the analysis. The coreflood results revealed that the gas recovery increases for increasing PVI and that there is an observation of pressure drop across the core for increasing PVI and this phenomenon is attributed to enhancing concentration of fines. Additionally, the water flow velocity elevates the velocity of coal fines and the microstructural analysis indicated the presence of kaolinite flakes among coal fines. The entire experimental model was tested against the statistical model in SPSS and showed good agreement. Overall, it is understood that even lignite reservoirs are prone to fines migration and permeability decline.

Madurai Block belt is the largest high among the crustal fragments of the Southern Granulite Terr... more Madurai Block belt is the largest high among the crustal fragments of the Southern Granulite Terrane. Our study focuses on the southeastern part of the Madurai Block which falls in the Thoothukudi District of Tamil Nadu. The geomorphology of the area is represented by high and mid-land regions with prominent hillocks and associated valleys. This region chiefly comprises of crystalline basement rocks that experienced granulite facies metamorphism. The southeastern region has been mapped, and the major rock types observed were identified as charnockite, hornblende-biotite gneiss, pyroxene granulite, quartzite, granite, pink granite and pegmatite. Massive garnet bearing charnockite exists as hills and which are intermixed with banded and migmatised hornblende-biotite gneiss. Diorite occurs as boudins and small enclaves within the charnockite. The charnockite occurs as both massive and foliated rocks in outcrops. A 5 km long intrusive body of pyroxene granulite is identified during the field study which trends NW-SE. Due to intense weathering they are found as boulders of varying size and shape.

In the current revision, to examine analytical hierarchy system has been apply toward the describ... more In the current revision, to examine analytical hierarchy system has been apply toward the describe groundwater potential founded on incorporated Geographic Information System (GIS) with Remote Sensing methods in Nagavathi Sub Basin, India. At initial the climatic reason, topographic factors, water related factors, geological factors, hydro geological factors and other ecological factor for instance land use or land cowl plus soil depth were caused by the spatial geodatabase. Secondly, the 29 groundwater facts among high possible yield value of C 40 m 3 /h were composed and map in GIS. Out these, 20 cases (70 %) were arbitrarily elected for models training, and the remaining 9 cases (30 %) were used for the validation purposes. Then, the assigned weights of the mastic layers based totally on professional information have been normalized by using eigenvector technique of AHP. To organize groundwater potential guide, Weighted Linear Combination scheme was functional in GIS. Eventually the receiver running characteristic (ROC) curve become drawn for groundwater capacity map and the vicinity underneath curve (AUC) turned into computed. Results showed to the rainfall with slope percent aspect enclose the most and least weights respectively. Evaluation of results illustrate to facilitate the AHP technique (AUC = 75.20 %) execute good predication accuracy. Result of this revision could be valuable for better board of water resources in study area and give planners with decision maker to prepare appropriate groundwater investment plans for sustainable environment.

We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples... more We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples collected from Meluri district Nagaland, Naga Hills Ophiolite belt (NHO) and it consists of the Flysch Naga-Arakan-Yoma trough beyond the Indo-Myanmar border. It reflects one of the many components of the Himalayan Orogenic systems of Tethyan oceanic crust discovered in Nagaland at Meluri district of India and they have very well-preserved studies and can be identified to Upper Jurassic (Kimmeridgian-mid-Tithonian). As well as a continuous sequence of Kimmeridgian-mid-Tithonian, five radiolarian assemblages have been identified in this study. This is so far the first recovery of pelagic sediment assemblages (Radiolarians) from the Naga Hills Ophiolite complex. Samples of Naga Hills Ophiolite belts fell in the Sublitharenite, Litharenite, and Fe-shale Fe-sand area, and the A-CN-K diagram indicates that these sediments in the source region were exposed deep to moderate weathering conditions. In the discriminant plot, the Naga Hill-Ophiolite-Chert samples occupy the field of origin of the sediment quartzose, and the log (K 2 O/Na 2 O) versus SiO 2 samples fall into the active continental marginal

A detailed petrographic study was carried out in various rock types in Mettupalayam-Bhavani Compl... more A detailed petrographic study was carried out in various rock types in Mettupalayam-Bhavani Complex in the northern parts of Southern Granulite Terrain, Tamil Nadu. Petrographic analysis aided in the identification of textural and mineralogical components present in the different rock types in the study area. Petrographical features of the rock types facilitated in the characterization of lithologies which composed the study area. Based on the present study, the rocks types in the region is mainly classified into gneissic rocks and granulitic rocks. The gneissic rock, the major composition of the study area, is identified as hornblende-biotite gneiss and biotite gneiss in the region. Granulite rocks involves the rock types of gabbro, ultramafic rocks and charnockite. Amphibolite rocks exhibit as foliated. Granites are identified as felsic rich domains. Quartzite rocks are composed of magnetite inclusions. Granulitic rocks often manifest the distinctive textural characters of geologic processes. The present study suggest that the petrographic characters of granulites and gneisses deduce the igneous and metamorphic activities in the formulation of the Mettupalayam-Bhavani Complex manifesting the distinctive textural characters of geologic processes.

The Kadavur massif-type anorthosite, which intruded the basement of the Madurai Block in southern... more The Kadavur massif-type anorthosite, which intruded the basement of the Madurai Block in southern India, comprises anorthosite, leucogabbro, and (noritic) gabbro with minor Fe-Ti oxide ores. The U-Pb zircon SIMS dating indicates that the magmatism occurred during the Neoproterozoic period (Tonian), i.e., noritic gabbro (790.4 ± 5.1 Ma), gabbro (793.0 ± 4.1 Ma), leucogabbro (784.9 ± 4.1 Ma), and anorthosite (790.7 ± 4.3 Ma). Combined with the published age data from the coeval charnockite and A-type granite, we conclude that the anorthosite-charnockite-rapakivi granite suite was emplaced during ca. 785-805 Ma. In-situ zircon Hf-O isotopic data of the Kadavur gabbros and anorthosite provide insights on the source and evolution of the parental magmas of the massif-type anorthosites. Zircons from the anorthosite are characterized by ancient crustal ε Hf (T) values (−11.4 to −6.5) and higher δ 18 O values (5.92 to 6.4‰). In contrast, zircons from the coarse-grained gabbro have relatively primitive ε Hf (T) values (−6.3 to −2.3) and mantle-like δ 18 O values (4.86-5.73‰). Moreover, zircons from the noritic gabbro and leucogabbro have ε Hf (T) values (−11.1 to −3.7) and δ 18 O values (5.35 to 6.77‰) distributed between those of the anorthosite and coarse-grained gabbro. The new zircon Hf-O data demonstrate that the parental melt of the anorthosite was subjected to crustal contamination during the early evolution stages, producing an evolved magma with crustal isotope and trace element signatures. In contrast, the gabbros show less crustal influence and like to represent original magma source of the Kadavur Complex. The zircon Hf-O isotope compositional array from the primitive gabbros to the more-evolved anorthosite demonstrates that the parental magmas were derived from partial melting of the upper mantle with varying crustal input, which can be up to 30-40% for the anorthosite formation. Contamination of the ponded basaltic magmas by the felsic crust can effectively increase the SiO 2 , Al 2 O 3 , Na 2 O, and Sr contents in the magmas, which was likely essential for enormous plagioclase fractionation in the massif-type anorthosites.

Mumbai is surrounded by many wetlands, including mudflats, mangroves, saltpans, creeks, freshwate... more Mumbai is surrounded by many wetlands, including mudflats, mangroves, saltpans, creeks, freshwater lakes, and estuaries. Because the city is so developed, the greatest threat to the wetland ecology is population growth and urbanisation.Thane Creek is more important than the others in those wetlands because it borders the most valuable mangroves and mudflats. Thane Creek (also Thana Creek) is an inlet in the Arabian Sea shoreline that connects Mumbai (Bombay) to the Konkan region of India.Sentinel 2b data was used to map the distribution of wetland habitats in the study area. This study identified four separate units: creek, mangrove, mudflats and urban from a supervised classification using Sentinel 2b data. The classification is based on the defined spectral signatures for the supervised representative samples required for each land cover class. Thane is the most significant creek in the Mumbai region. 55.5 km 2 area was classified as the creek, around 30 % of the total study area. Similarly, 43.5 km 2 area was classified as the mangroves, which is around 23 %. When classifying mudflats, they covered 51 km 2 area, around 27 % of the total study area. Urban growth is rapid in this part. As a result, 37.73 km 2 area was classified as a metropolitan area. Mudflats in the study area are in massively unsafe conditions because of urbanisation. This study confirmed that the Mangrove area is more stable because of strict orders of the High Court compared to the past, though they are under threat by urbanisation.

Kanyakumari is the southernmost coastal district of India and the state of Tamil Nadu. Due to the... more Kanyakumari is the southernmost coastal district of India and the state of Tamil Nadu. Due to the rapid increase in the population, the district's land use and land cover areas experience enormous changes in the past few years. So, the study of Land Use and Land Cover Changes in the district is much required for the current scenario. Landsat 8 images were used for the supervised classification. The cultivable cropland, barren land, beachface landcover and dune cover vegetation decrease in their area because of the rapid growth of urbanisation. The Fallow land, the plantation, saltpans, built-up area and the beach mining areas show an increasing trend in their areas in the study area. The plantation, the fallow land and the beach mining only increase a little in their area, but the saltpans and the built-up areas increase rapidly. The rapid increase of the saltpans and the built-up area show rapid urbanization in the study area. The unfettered changes in the LULC feature are alarming the coastal vulnerability in the Kanyakumari districts coastal villages. This study offers pilot information for sustainable coastal management and suggests planning to decrease coastal regions' risk and vulnerability.

Mumbai is richly surrounded by unique types of wetlands such as mudflats, mangroves, saltpans, cr... more Mumbai is richly surrounded by unique types of wetlands such as mudflats, mangroves, saltpans, creeks, freshwater lakes, and estuaries.As the city is highly developed, population explosion and the urbanization are the greatest threat for the wetland ecosystem. Wetland mapping and classification were carried out using the sentinel 2b data for Mumbai and the adjoining areas.Sentinel 2b data from 28th May 2019 was used in this study.The data was processed in the SNAP (Sentinel Application Platform) toolbox.Classification of wetlands has carried out in both pixel-based and index-based techniques.Six different classes were defined in the pixel-based classification they are Backwater, Mangroves, creek water & inland waters, urban area, Forest, and sea.Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Modified Soil-adjusted Vegetation Index (MSAVI2) were calculated in the index-based classification. As per the pixel-based classification results, the percentage of the backwater is 8.54 in the study area, which is 137.077 km 2. 67.089 square kilometers are classified as Mangroves.Creeks and Inland water are occupying 6.89% of the total study area with the 110.58 km 2 .Saltpans and the Mudflats are the other wetlands found in the study area.Saltpans in Mumbai are around 20km 2, and it is difficult to classify. Mudflatsare mainly found, and around the Thane creek,and the total area of the Mudflat in the Thane creek is classified as 51 km 2 .For the reliability of the result and validating the remote sensing classification, the error matrix technique was carried out.The overall accuracy of the supervised classification result of the study area is found as 0.92. With the overall accuracy of 0.92, the study proved that the sentinel data is more capable of mapping wetlands though it shows less accuracy for classifying the water bodies.The study shows thatSaltpans and Mudflats are massively in unsafe conditions. This study confirmed that the Mangrove area is found to be more stable,maybe because of strict orders of the High Court when compared to the past, though they are under threat by urbanization.

A study to identifying the varied coastal geomorphic characteristics along the coast of the Kanya... more A study to identifying the varied coastal geomorphic characteristics along the coast of the Kanyakumari district has been attempted. Geomorphic features resulting from diverse coastal and landward processes define the study region. According to the evolution process, the coastal landforms in the Kanyakumari district are classified into four main classifications 1) marine landforms, 2) fluviomarine landforms, 3) fluvial landforms, 4) aeolian landforms. Sea level fluctuations and land-sea interaction combine to create diversified coastal geomorphology along the coast. The sandy beaches, dune system, intertidal deposits, Teri sand dunes, wave-cut notches, beach terraces, rocky shores, estuaries, beach berms and cusps, sand bars are described in detail and the significance of their occurrence. The coastal geomorphology of the study area proves sea level changes and fluctuations in climatic conditions in this section of the coast.

Phyllosilicates, specifically, the kaolinite clay mineral (Al 2 Si 2 O 5 (OH) 4), which is a laye... more Phyllosilicates, specifically, the kaolinite clay mineral (Al 2 Si 2 O 5 (OH) 4), which is a layered silicate mineral with one silica tetrahedral sheet connected with oxygen atoms to one alumina octahedral octahedral sheet is ubiquitous and abundant in sedimentary basins, especially sandstone formations. This particular type of clay mineral fine particles can easily and rapidly cause reservoir formation damage in high temperature aquifers, geothermal, and petroleum reservoirs by detaching from the porous rock surface and migrate, and plug the pore-throats of the rock matrix. Several factors such as, reservoir temperature, pressure, geochemical alteration, permeating fluid, reactive flow, and multi-phase flow are attributed to the permeability decline of the porous rocks and subsequent fluid flow reduction, and consequently, leading to well productivity loss. Therefore, this paper presents laboratory modeling of fines transport in the hot porous sedimentary aquifer. This type of aquifer is located in sedimentary basins with the elevated heat flow and having a characteristic of a shallow depth and a high volume, which indicates a high natural porosity and permeability. In this work, we have conducted three sets of coreflood experiments in the temperature ranges of 125 • C 150 • C, and 175 • C. Kaolinite suspension water has been injected into the porous sandstone core at these temperatures to investigate the feasibility of a permeability and injectivity decline. The major experimental results revealed that there is an increase in water saturation and heat transfer rates. The concentration of fines surges with increasing PVI and permeability declines with increased time. Pressure soars with increasing Pore Volume Injection (PVI), but it stabilized after some time. Actually, PVI is a ratio of cumulative water injection to each pore chamber volume of the rock core. Importantly, the water discharge rate decreases with increasing suspension injection and on the other side, with fresh water injection, the rate of water discharge rises steadily. Furthermore, the experimental and mathematical models were tested against statistical model, multiple linear regression for validation. The modelling results showed good agreement and, therefore, this paper has explicated the significance of fines transport in aquifers under hot sedimentary basins.

Rapid combustion of fossil fuels in huge quantities resulted in the enormous release of CO 2 in t... more Rapid combustion of fossil fuels in huge quantities resulted in the enormous release of CO 2 in the atmosphere. Subsequently, leading to the greenhouse gas effect and climate change and contemporarily, quest and usage of fossil fuels has increased dramatically in recent times. The only solution to resolve the problem of CO 2 emissions to the atmosphere is geological/ subsurface storage of carbon dioxide or carbon capture and storage (CCS). Additionally, CO 2 can be employed in the oil and gas fields for enhanced oil recovery operations and this cyclic form of the carbon dioxide injection into reservoirs for recovering oil and gas is known as CO 2 Enhanced Oil and Gas Recovery (EOGR). Hence, this paper presents the CO 2 retention dominance in tight oil and gas reservoirs in the Western Canadian Sedimentary Basin (WCSB) of the Alberta Province, Canada. Actually, hysteresis modeling was applied in the oil and gas reservoirs of WCSB for sequestering or trapping CO 2 and EOR as well. Totally, four cases were taken for the investigation, such as WCSB Alberta tight oil and gas reservoirs with CO 2 huff-n-puff and flooding processes. Actually, Canada has complex geology and therefore, implicate that it can serve as a promising candidate that is suitable and safer place for CO 2 storage. Furthermore, injection pressure, time, rate (mass), number of cycles, soaking time, fracture half-length, conductivity, porosity, permeability, and initial reservoir pressure were taken as input parameters and cumulative oil production and oil recovery factor are the output parameters, this is mainly for tight oil reservoirs. In the tight gas reservoirs, only the output parameters differ from the oil reservoir, such as cumulative gas production and gas recovery factor. Reservoirs were modelled to operate for 30 years of oil and gas production and the factor year was designated as decision-making unit (DMU). CO 2 retention was estimated in all four models and overall the gas retention in four cases showed a near sinusoidal behavior and the variations are sporadic. More than 80% CO 2 retention in these tight formations were achieved and the major influencing factors that govern the CO 2 storage in these tight reservoirs are injection pressure, time, mass, number of cycles, and soaking time. In general, the subsurface geology of the Canada is very complex consisting with many structural and stratigraphic layers and thus, it offers safe location for CO 2 storage through retention mechanism and increasing the efficiency and reliability of oil and gas extraction from these complicated subsurface formations.

Microplastics (MPs) have received widespread attention as an emerging environmental pollutant. Th... more Microplastics (MPs) have received widespread attention as an emerging environmental pollutant. They are ubiquitous in the freshwater system and have caused a global environmental issue. The terrestrial component of the Noyyal River sediments microplastic is poorly understood due to a lack of quantification of sources, stores, and fluxes. We have presented catchment-wide patterns of microplastic contamination, classified by type, Shape, size, and color, in channel bed sediments from 15 sites in Coimbatore's urban river catchments. In this research, we identified the concentrations of MPs ranging from 500 to 6500 n/m 3 at river mouths (dried sediments). In sediments, microplastics are found in a variety of shapes, colors, and compositions, with green, blue, white, transparent, and other colors predominating. MPs components were identified and analyzed by ATR-FTIR (PP, PET, PS, LDPE, and PVAC). The present study is the first comprehensive study of western Tamilnadu, and the findings raise public awareness of the risks of microplastic pollution. This study also discusses the technique used, as well as the impacts and effects of MPs on the environment. Future perspectives are also thoroughly discussed in this study.

Coastal areas, the place where the water of the sea meet the land are indeed unique places in our... more Coastal areas, the place where the water of the sea meet the land are indeed unique places in our global geography. Coastal zones are dynamic interfaces between land and water and are common locations of high-density development. Monitoring shoreline changes help to identify the nature and processes that caused these changes in any specific area, to assess the human impact and to plan management strategies. Remote sensing data could be used effectively to monitor the changes along the coastal zone, including shoreline with reasonable accuracy it has been taken up. The study area is the district of Pondicherry, which is the first largest among the four regions ,and it has an area of 293 km 2 .The study area falls in the Survey of India Topographic Map nos. of 58M/13 and 58P/16 on 1:50,000 scale. Detailed geomorphological was done based on mapping has been done using IRS P5 (2011) data and Survey of India Topographic map. In the present study, detailed coastal geomorphologic landforms of fluvial, coastal and uplands were studied.

Coal fines production and structural collapse during waterflooding process was widely observed an... more Coal fines production and structural collapse during waterflooding process was widely observed and reported in several coalbed methane (CBM) fields. Besides, fines migration also plays a major role in the destruction of coal cleats and consequently, declining the gas recovery. This paper presents the coal fines production in lignite core as a function of kaolinite. Actually, it is a clay fine particle that rests on coal surface under the dominances of the four forces, namely, lift, drag, gravity, and electrostatics. Under hydrodynamic and thermodynamic forces these fines detach from the rock surface and migrate in the porous interspace, and at a certain point it is captured, and thereby deteriorating the well productivity and structural collapse as well. Many researchers have investigated these fines migration mechanisms in anthracite and bituminous coals, but to best of our knowledge till date this research was not carried out in lignite coals. In order to successfully demonstrate this mechanism in lignite, three sets of coreflood experiments have been conducted under ambient conditions for analyzing the coal and kaolinite fines transport and their impact on gas recovery. Lignite samples are procured from Neyveli Mines at Cauvery Basin in Southern India and then the simulated version is used for the analysis. The coreflood results revealed that the gas recovery increases for increasing PVI and that there is an observation of pressure drop across the core for increasing PVI and this phenomenon is attributed to enhancing concentration of fines. Additionally, the water flow velocity elevates the velocity of coal fines and the microstructural analysis indicated the presence of kaolinite flakes among coal fines. The entire experimental model was tested against the statistical model in SPSS and showed good agreement. Overall, it is understood that even lignite reservoirs are prone to fines migration and permeability decline.

Madurai Block belt is the largest high among the crustal fragments of the Southern Granulite Terr... more Madurai Block belt is the largest high among the crustal fragments of the Southern Granulite Terrane. Our study focuses on the southeastern part of the Madurai Block which falls in the Thoothukudi District of Tamil Nadu. The geomorphology of the area is represented by high and mid-land regions with prominent hillocks and associated valleys. This region chiefly comprises of crystalline basement rocks that experienced granulite facies metamorphism. The southeastern region has been mapped, and the major rock types observed were identified as charnockite, hornblende-biotite gneiss, pyroxene granulite, quartzite, granite, pink granite and pegmatite. Massive garnet bearing charnockite exists as hills and which are intermixed with banded and migmatised hornblende-biotite gneiss. Diorite occurs as boudins and small enclaves within the charnockite. The charnockite occurs as both massive and foliated rocks in outcrops. A 5 km long intrusive body of pyroxene granulite is identified during the field study which trends NW-SE. Due to intense weathering they are found as boulders of varying size and shape.

In the current revision, to examine analytical hierarchy system has been apply toward the describ... more In the current revision, to examine analytical hierarchy system has been apply toward the describe groundwater potential founded on incorporated Geographic Information System (GIS) with Remote Sensing methods in Nagavathi Sub Basin, India. At initial the climatic reason, topographic factors, water related factors, geological factors, hydro geological factors and other ecological factor for instance land use or land cowl plus soil depth were caused by the spatial geodatabase. Secondly, the 29 groundwater facts among high possible yield value of C 40 m 3 /h were composed and map in GIS. Out these, 20 cases (70 %) were arbitrarily elected for models training, and the remaining 9 cases (30 %) were used for the validation purposes. Then, the assigned weights of the mastic layers based totally on professional information have been normalized by using eigenvector technique of AHP. To organize groundwater potential guide, Weighted Linear Combination scheme was functional in GIS. Eventually the receiver running characteristic (ROC) curve become drawn for groundwater capacity map and the vicinity underneath curve (AUC) turned into computed. Results showed to the rainfall with slope percent aspect enclose the most and least weights respectively. Evaluation of results illustrate to facilitate the AHP technique (AUC = 75.20 %) execute good predication accuracy. Result of this revision could be valuable for better board of water resources in study area and give planners with decision maker to prepare appropriate groundwater investment plans for sustainable environment.

We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples... more We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples collected from Meluri district Nagaland, Naga Hills Ophiolite belt (NHO) and it consists of the Flysch Naga-Arakan-Yoma trough beyond the Indo-Myanmar border. It reflects one of the many components of the Himalayan Orogenic systems of Tethyan oceanic crust discovered in Nagaland at Meluri district of India and they have very well-preserved studies and can be identified to Upper Jurassic (Kimmeridgian-mid-Tithonian). As well as a continuous sequence of Kimmeridgian-mid-Tithonian, five radiolarian assemblages have been identified in this study. This is so far the first recovery of pelagic sediment assemblages (Radiolarians) from the Naga Hills Ophiolite complex. Samples of Naga Hills Ophiolite belts fell in the Sublitharenite, Litharenite, and Fe-shale Fe-sand area, and the A-CN-K diagram indicates that these sediments in the source region were exposed deep to moderate weathering conditions. In the discriminant plot, the Naga Hill-Ophiolite-Chert samples occupy the field of origin of the sediment quartzose, and the log (K 2 O/Na 2 O) versus SiO 2 samples fall into the active continental marginal

A detailed petrographic study was carried out in various rock types in Mettupalayam-Bhavani Compl... more A detailed petrographic study was carried out in various rock types in Mettupalayam-Bhavani Complex in the northern parts of Southern Granulite Terrain, Tamil Nadu. Petrographic analysis aided in the identification of textural and mineralogical components present in the different rock types in the study area. Petrographical features of the rock types facilitated in the characterization of lithologies which composed the study area. Based on the present study, the rocks types in the region is mainly classified into gneissic rocks and granulitic rocks. The gneissic rock, the major composition of the study area, is identified as hornblende-biotite gneiss and biotite gneiss in the region. Granulite rocks involves the rock types of gabbro, ultramafic rocks and charnockite. Amphibolite rocks exhibit as foliated. Granites are identified as felsic rich domains. Quartzite rocks are composed of magnetite inclusions. Granulitic rocks often manifest the distinctive textural characters of geologic processes. The present study suggest that the petrographic characters of granulites and gneisses deduce the igneous and metamorphic activities in the formulation of the Mettupalayam-Bhavani Complex manifesting the distinctive textural characters of geologic processes.

The Kadavur massif-type anorthosite, which intruded the basement of the Madurai Block in southern... more The Kadavur massif-type anorthosite, which intruded the basement of the Madurai Block in southern India, comprises anorthosite, leucogabbro, and (noritic) gabbro with minor Fe-Ti oxide ores. The U-Pb zircon SIMS dating indicates that the magmatism occurred during the Neoproterozoic period (Tonian), i.e., noritic gabbro (790.4 ± 5.1 Ma), gabbro (793.0 ± 4.1 Ma), leucogabbro (784.9 ± 4.1 Ma), and anorthosite (790.7 ± 4.3 Ma). Combined with the published age data from the coeval charnockite and A-type granite, we conclude that the anorthosite-charnockite-rapakivi granite suite was emplaced during ca. 785-805 Ma. In-situ zircon Hf-O isotopic data of the Kadavur gabbros and anorthosite provide insights on the source and evolution of the parental magmas of the massif-type anorthosites. Zircons from the anorthosite are characterized by ancient crustal ε Hf (T) values (−11.4 to −6.5) and higher δ 18 O values (5.92 to 6.4‰). In contrast, zircons from the coarse-grained gabbro have relatively primitive ε Hf (T) values (−6.3 to −2.3) and mantle-like δ 18 O values (4.86-5.73‰). Moreover, zircons from the noritic gabbro and leucogabbro have ε Hf (T) values (−11.1 to −3.7) and δ 18 O values (5.35 to 6.77‰) distributed between those of the anorthosite and coarse-grained gabbro. The new zircon Hf-O data demonstrate that the parental melt of the anorthosite was subjected to crustal contamination during the early evolution stages, producing an evolved magma with crustal isotope and trace element signatures. In contrast, the gabbros show less crustal influence and like to represent original magma source of the Kadavur Complex. The zircon Hf-O isotope compositional array from the primitive gabbros to the more-evolved anorthosite demonstrates that the parental magmas were derived from partial melting of the upper mantle with varying crustal input, which can be up to 30-40% for the anorthosite formation. Contamination of the ponded basaltic magmas by the felsic crust can effectively increase the SiO 2 , Al 2 O 3 , Na 2 O, and Sr contents in the magmas, which was likely essential for enormous plagioclase fractionation in the massif-type anorthosites.

Mumbai is surrounded by many wetlands, including mudflats, mangroves, saltpans, creeks, freshwate... more Mumbai is surrounded by many wetlands, including mudflats, mangroves, saltpans, creeks, freshwater lakes, and estuaries. Because the city is so developed, the greatest threat to the wetland ecology is population growth and urbanisation.Thane Creek is more important than the others in those wetlands because it borders the most valuable mangroves and mudflats. Thane Creek (also Thana Creek) is an inlet in the Arabian Sea shoreline that connects Mumbai (Bombay) to the Konkan region of India.Sentinel 2b data was used to map the distribution of wetland habitats in the study area. This study identified four separate units: creek, mangrove, mudflats and urban from a supervised classification using Sentinel 2b data. The classification is based on the defined spectral signatures for the supervised representative samples required for each land cover class. Thane is the most significant creek in the Mumbai region. 55.5 km 2 area was classified as the creek, around 30 % of the total study area. Similarly, 43.5 km 2 area was classified as the mangroves, which is around 23 %. When classifying mudflats, they covered 51 km 2 area, around 27 % of the total study area. Urban growth is rapid in this part. As a result, 37.73 km 2 area was classified as a metropolitan area. Mudflats in the study area are in massively unsafe conditions because of urbanisation. This study confirmed that the Mangrove area is more stable because of strict orders of the High Court compared to the past, though they are under threat by urbanisation.

Kanyakumari is the southernmost coastal district of India and the state of Tamil Nadu. Due to the... more Kanyakumari is the southernmost coastal district of India and the state of Tamil Nadu. Due to the rapid increase in the population, the district's land use and land cover areas experience enormous changes in the past few years. So, the study of Land Use and Land Cover Changes in the district is much required for the current scenario. Landsat 8 images were used for the supervised classification. The cultivable cropland, barren land, beachface landcover and dune cover vegetation decrease in their area because of the rapid growth of urbanisation. The Fallow land, the plantation, saltpans, built-up area and the beach mining areas show an increasing trend in their areas in the study area. The plantation, the fallow land and the beach mining only increase a little in their area, but the saltpans and the built-up areas increase rapidly. The rapid increase of the saltpans and the built-up area show rapid urbanization in the study area. The unfettered changes in the LULC feature are alarming the coastal vulnerability in the Kanyakumari districts coastal villages. This study offers pilot information for sustainable coastal management and suggests planning to decrease coastal regions' risk and vulnerability.

Mumbai is richly surrounded by unique types of wetlands such as mudflats, mangroves, saltpans, cr... more Mumbai is richly surrounded by unique types of wetlands such as mudflats, mangroves, saltpans, creeks, freshwater lakes, and estuaries.As the city is highly developed, population explosion and the urbanization are the greatest threat for the wetland ecosystem. Wetland mapping and classification were carried out using the sentinel 2b data for Mumbai and the adjoining areas.Sentinel 2b data from 28th May 2019 was used in this study.The data was processed in the SNAP (Sentinel Application Platform) toolbox.Classification of wetlands has carried out in both pixel-based and index-based techniques.Six different classes were defined in the pixel-based classification they are Backwater, Mangroves, creek water & inland waters, urban area, Forest, and sea.Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Modified Soil-adjusted Vegetation Index (MSAVI2) were calculated in the index-based classification. As per the pixel-based classification results, the percentage of the backwater is 8.54 in the study area, which is 137.077 km 2. 67.089 square kilometers are classified as Mangroves.Creeks and Inland water are occupying 6.89% of the total study area with the 110.58 km 2 .Saltpans and the Mudflats are the other wetlands found in the study area.Saltpans in Mumbai are around 20km 2, and it is difficult to classify. Mudflatsare mainly found, and around the Thane creek,and the total area of the Mudflat in the Thane creek is classified as 51 km 2 .For the reliability of the result and validating the remote sensing classification, the error matrix technique was carried out.The overall accuracy of the supervised classification result of the study area is found as 0.92. With the overall accuracy of 0.92, the study proved that the sentinel data is more capable of mapping wetlands though it shows less accuracy for classifying the water bodies.The study shows thatSaltpans and Mudflats are massively in unsafe conditions. This study confirmed that the Mangrove area is found to be more stable,maybe because of strict orders of the High Court when compared to the past, though they are under threat by urbanization.

A study to identifying the varied coastal geomorphic characteristics along the coast of the Kanya... more A study to identifying the varied coastal geomorphic characteristics along the coast of the Kanyakumari district has been attempted. Geomorphic features resulting from diverse coastal and landward processes define the study region. According to the evolution process, the coastal landforms in the Kanyakumari district are classified into four main classifications 1) marine landforms, 2) fluviomarine landforms, 3) fluvial landforms, 4) aeolian landforms. Sea level fluctuations and land-sea interaction combine to create diversified coastal geomorphology along the coast. The sandy beaches, dune system, intertidal deposits, Teri sand dunes, wave-cut notches, beach terraces, rocky shores, estuaries, beach berms and cusps, sand bars are described in detail and the significance of their occurrence. The coastal geomorphology of the study area proves sea level changes and fluctuations in climatic conditions in this section of the coast.

Phyllosilicates, specifically, the kaolinite clay mineral (Al 2 Si 2 O 5 (OH) 4), which is a laye... more Phyllosilicates, specifically, the kaolinite clay mineral (Al 2 Si 2 O 5 (OH) 4), which is a layered silicate mineral with one silica tetrahedral sheet connected with oxygen atoms to one alumina octahedral octahedral sheet is ubiquitous and abundant in sedimentary basins, especially sandstone formations. This particular type of clay mineral fine particles can easily and rapidly cause reservoir formation damage in high temperature aquifers, geothermal, and petroleum reservoirs by detaching from the porous rock surface and migrate, and plug the pore-throats of the rock matrix. Several factors such as, reservoir temperature, pressure, geochemical alteration, permeating fluid, reactive flow, and multi-phase flow are attributed to the permeability decline of the porous rocks and subsequent fluid flow reduction, and consequently, leading to well productivity loss. Therefore, this paper presents laboratory modeling of fines transport in the hot porous sedimentary aquifer. This type of aquifer is located in sedimentary basins with the elevated heat flow and having a characteristic of a shallow depth and a high volume, which indicates a high natural porosity and permeability. In this work, we have conducted three sets of coreflood experiments in the temperature ranges of 125 • C 150 • C, and 175 • C. Kaolinite suspension water has been injected into the porous sandstone core at these temperatures to investigate the feasibility of a permeability and injectivity decline. The major experimental results revealed that there is an increase in water saturation and heat transfer rates. The concentration of fines surges with increasing PVI and permeability declines with increased time. Pressure soars with increasing Pore Volume Injection (PVI), but it stabilized after some time. Actually, PVI is a ratio of cumulative water injection to each pore chamber volume of the rock core. Importantly, the water discharge rate decreases with increasing suspension injection and on the other side, with fresh water injection, the rate of water discharge rises steadily. Furthermore, the experimental and mathematical models were tested against statistical model, multiple linear regression for validation. The modelling results showed good agreement and, therefore, this paper has explicated the significance of fines transport in aquifers under hot sedimentary basins.

Rapid combustion of fossil fuels in huge quantities resulted in the enormous release of CO 2 in t... more Rapid combustion of fossil fuels in huge quantities resulted in the enormous release of CO 2 in the atmosphere. Subsequently, leading to the greenhouse gas effect and climate change and contemporarily, quest and usage of fossil fuels has increased dramatically in recent times. The only solution to resolve the problem of CO 2 emissions to the atmosphere is geological/ subsurface storage of carbon dioxide or carbon capture and storage (CCS). Additionally, CO 2 can be employed in the oil and gas fields for enhanced oil recovery operations and this cyclic form of the carbon dioxide injection into reservoirs for recovering oil and gas is known as CO 2 Enhanced Oil and Gas Recovery (EOGR). Hence, this paper presents the CO 2 retention dominance in tight oil and gas reservoirs in the Western Canadian Sedimentary Basin (WCSB) of the Alberta Province, Canada. Actually, hysteresis modeling was applied in the oil and gas reservoirs of WCSB for sequestering or trapping CO 2 and EOR as well. Totally, four cases were taken for the investigation, such as WCSB Alberta tight oil and gas reservoirs with CO 2 huff-n-puff and flooding processes. Actually, Canada has complex geology and therefore, implicate that it can serve as a promising candidate that is suitable and safer place for CO 2 storage. Furthermore, injection pressure, time, rate (mass), number of cycles, soaking time, fracture half-length, conductivity, porosity, permeability, and initial reservoir pressure were taken as input parameters and cumulative oil production and oil recovery factor are the output parameters, this is mainly for tight oil reservoirs. In the tight gas reservoirs, only the output parameters differ from the oil reservoir, such as cumulative gas production and gas recovery factor. Reservoirs were modelled to operate for 30 years of oil and gas production and the factor year was designated as decision-making unit (DMU). CO 2 retention was estimated in all four models and overall the gas retention in four cases showed a near sinusoidal behavior and the variations are sporadic. More than 80% CO 2 retention in these tight formations were achieved and the major influencing factors that govern the CO 2 storage in these tight reservoirs are injection pressure, time, mass, number of cycles, and soaking time. In general, the subsurface geology of the Canada is very complex consisting with many structural and stratigraphic layers and thus, it offers safe location for CO 2 storage through retention mechanism and increasing the efficiency and reliability of oil and gas extraction from these complicated subsurface formations.

Microplastics (MPs) have received widespread attention as an emerging environmental pollutant. Th... more Microplastics (MPs) have received widespread attention as an emerging environmental pollutant. They are ubiquitous in the freshwater system and have caused a global environmental issue. The terrestrial component of the Noyyal River sediments microplastic is poorly understood due to a lack of quantification of sources, stores, and fluxes. We have presented catchment-wide patterns of microplastic contamination, classified by type, Shape, size, and color, in channel bed sediments from 15 sites in Coimbatore's urban river catchments. In this research, we identified the concentrations of MPs ranging from 500 to 6500 n/m 3 at river mouths (dried sediments). In sediments, microplastics are found in a variety of shapes, colors, and compositions, with green, blue, white, transparent, and other colors predominating. MPs components were identified and analyzed by ATR-FTIR (PP, PET, PS, LDPE, and PVAC). The present study is the first comprehensive study of western Tamilnadu, and the findings raise public awareness of the risks of microplastic pollution. This study also discusses the technique used, as well as the impacts and effects of MPs on the environment. Future perspectives are also thoroughly discussed in this study.