Contrasting mineralogy and strain partitioning across N-S oriented Sitampundi - Kanjamalai Shear in Sitampundi Anorthosite Layered Complex

Sitampundi Anorthosite Layered Complex (SALC) is a complexly folded and metamorphosed terrain that shows different metamorphic grade separated by a regional linear divide. In the north-eastern part of the complex, the anorthosites contain green-colored clinozoisites that are strikingly absent in the western part of the limb. Based on the presence of the clinozoisites, the entire SALC can be divided into two zones. The Sitampundi-Kanjamalai shear zone (SKSZ) separates mega crystals of clinozoite bearing anorthosites from clinozoisite free anorthosites. To add furthermore, strain analysis of different samples of anorthosite on either side of the zones was conducted by employing Flinn method. In general, anorthosites fall into the flattening field. The clinozoisite free anorthosites are more flattening and clinozoisite bearing anorthosites exhibit a slight difference in their strain ratio, ie., it is comparatively less flattening. Geochemistry of clinozoisites was studied using EPMA & XRD methods. The percentage of oxides obtained from EPMA coincides with that of epidote. But, XRD confirms the mineral to be clinozoisite indicating the transition phase of epidote to clinozoisite. Zoning has had occurred in clinozoisites with aluminium oxide rich core and FeO rich rim. This could be related to a retrogression corresponding to a shearing event.

A Preliminary Study on Microplastic Occurrences in Surface Waters of Ousudu Lake, Pondicherry, India.

Microplastics (MP) in both freshwater and marine ecosystem is the next issue that has been recently the fore. However, freshwaters are the potential source and pathway to transport MPs to the marine environment. There is a lack of understanding about the presence and analysis of MP in the freshwater system in India, one of the leading global plastic producers and consumers responsible for 5.6 million tonnes of waste every year. The present attempt is the first in Ousudu Lake, Puducherry, Tamil Nadu, to study the MPs occurrence and examine its properties in the surface water of the largest lake and an important wetland. The concentration range of MP in Ousudu Lake was 0.0039 particles/m2. Fibre was dominant, homogenous with the size fraction of ≤100µm comprised of total MPs collected in Lake. Raman spectroscopy identified plastics with polyethylene as a homogenous component. This study indicated that the presence of MP in water might influence the environment.

Assessment of seasonal groundwater quality using CHIDAM software in Virudhunagar district of Tamil Nadu.

Hard rock aquifer is the most predominant in the southern peninsula exclusively in Tamil Nadu, India. Virudhunagar district is situated in the South west part of Tamil Nadu, mostly of hard rock topography. Groundwater plays a major role in this area contributing to domestic, irrigation and industrial practices. Running down of groundwater by extreme consumption and less recharge in the study area has reduced the level of groundwater. On the other hand, intensive domestic, agriculture and industrial practices impacts the quality of quality of groundwater as well. Hydro geochemistry plays an important role in evaluation of suitability of groundwater for its usage in several purposes. A total of 72 samples from North East Monsoon (NEM) and Post Monsoon (POM) has been analyzed hydrochemically. The irrigation quality parameters such as sodium adsorption ratio (SAR), %Na, Residual Sodium Carbonate (RSC), Kelley’s index and Magnesium hazard were calculated using CHIDAM software 2020 in conjunction with USSL and Doneen diagrams. During NEM, EC and TDS ranges from 273 to 5869 mg/L and 194 to 4159 mg/L and during POM is from 235 to 6850 mg/L and 233.8 to 6916 mg/L. The hydrogeochemical facies represents that Ca-HCO3 and mixed Ca-Mg-Cl facies are predominant during NEM and Na-Cl and mixed Ca-Mg-Cl are predominant during POM. The higher concentration of TDS and EC in the samples reflects the unsuitability of groundwater in both seasons.

Investigation of Submarine Groundwater Discharge using Thermal Satellite and Radon mapping along the East Coast of the Tamil Nadu and Pondicherry Region, India

Submarine groundwater discharge (SGD) demarcated as a significant component of hydrological cycle found to discharge greater volumes of terrestrial fresh and recirculated seawater to the ocean associated with chemical constituents (nutrients, metals, and organic compounds) aided by downward hydraulic gradient and sediment-water exchange. Delineating SGD is of primal significance due to the transport of nutrients and contaminants due to domestic, industrial, and agricultural practices that influence the coastal water quality, ecosystems, and geochemical cycles. An attempt has been made to demarcate the SGD using thermal infrared images and radon-222 (222Rn) isotope. Thermal infrared images processed from LANDSAT-8 data suggest prominent freshwater fluxes with higher temperature anomalies noted in Cuddalore and Nagapattinam districts, and lower temperature noted along northern and southern parts of the study area suggest saline/recirculated discharge. Groundwater samples were collected along the coastal regions to analyze Radon and Physico-chemical constituents. Radon in groundwater ranges between 127.39 Bq m-3 and 2643.41 Bq m-3 with an average of 767.80 Bq m-3. Calculated SGD fluxes range between -1.0 to 26.5 with an average of 10.32 m day-1. Comparison of the thermal infrared image with physio-chemical parameters and Radon suggest fresh, terrestrial SGD fluxes confined to the central parts of the study area and lower fluxes observed along with the northern and southern parts of the study area advocate impact due to seawater intrusion and recirculated seawater influence.

Experimental Investigation of Lightweight Wall Panel Using Cenosphere Incorporated with Ground Granulated Blast Furnace Slag

The secondary form of waste is the major outcome of the various industries. Likewise, Cenosphere and Ground Granulateds Blast Furnace Slag (GGBS) are the waste material obtained from thermal power plants and the steel industry. This waste requires a large land area for disposal. In such cases, these can be used in the construction field. This paper investigated the lightweight wall panel made with cenosphere and GGBS as a replacement for cementitious material. Cenosphere was replaced at 5%, 10%, 15%, 20%, 25% and 30% respectively by weight of cement and GGBS was at 15% constant replacement of cement. The properties of wall panels such as compressive strength, flexural strength, and water absorption have been studied. The flexural behavior was carried out by inhibition of fiber into the matrix. The samples were tested at 7, 14, and 28 days respectively. The SEM analysis of the cenosphere has been carried out. The results infer an increase in the percentage of cenosphere does not impart strength to the mix. Therefore, 15% of constant replacement of GGBS to the mass of cement stabilize the strength which was lost due to the addition of the cenosphere. On an overall view, it was recommended that the strength loss of mixture due to the addition of the cenosphere can be alleviated by GGBS and nevertheless a secure value of strength can be gained.

Assessment of sources and distribution metals in groundwater of Pondicherry region, India

The proposed study investigates the seasonal variation in the concentration and the source of the heavy metals like Mn, Cu, Pb, Zn and Fe in the groundwater samples of Pondicherry region. The study results reveal that, the heavy metal concentration is high during South West Monsoon season (SWM) compared to that of North East Monsoon season (NEM). The pH was near neutral and metal load representing most of the samples were low during NEM. Statistical analysis shows that the 63.7 % of the total variance is observed during NEM and 68.9% during SWM. Geographic information system (GIS) tool was considered for the study to understand the environmental pollution status of the groundwater systems of the study area and to identify the groundwater quality parameters. The multivariate statistical analysis explains that the source of trace metal in the groundwater is derived from natural origin except copper and lead as these contaminants were derived from anthropogenic activities. Based on the output of WATEQ4F, several species of heavy metals exist, in which the dominant species are Mn, CuCl2, PbCO3, Fe and Zn.

Fold pattern analysis around Kanjamalai Salem district Tamilnadu

Kanjamalai one of the fascinating location in Southern Granulite Terrain (SGT) for studying Archaean geology and structures as the entire hill is made up of variety of rock types like two pyroxene granulite, amphibolites, quartzo - feldsapthic gneisses, banded iron formation, and intrusive rocks like dunite, peridotite and pegmatite and beautifully carved structures. The entire hill resembles a canoe shape with doubly plunging fold structure with E-W elongation. The entire hillock seems to sit pretty on mylonitised hornblende biotite gneisses which also have a common N70-95 degree trend and sub vertical dip with NE plunge which is in contradiction to centrally plunging lineations of the hill. The SW part of Kanjamalai near Chinasrirangapadi was displaying beautiful fold structures, with interference pattern out of which six domains were selected for detailed study and analysis. The multiple generation folded structure will have a clue in reconstructing the deformation history of this Kanjamalai. The observed f1, f2 and f3 folds show significant Type III interference pattern as that of Ramsay and 01 and 03 type folds of Bernhard Grasemann. Wavelength –amplitude analysis was made to generalize and regroup the observed folds in to high amplitude, high wavelength or open folds, low wavelength and Mesoscopic folds. And visual harmonic analysis was made to analyse the symmetry of the folds and analyze the geometry, symmetry and harmony and genesis of the fold in terms of relative timing of the events.

Targeting groundwater potential zones using Electrical resistivity and GIS techniques in Kadavanar Sub-basin, South India

Geographical Information System techniques are widely used to determine suitable sites for groundwater recharge through artificial recharge techniques. The present research work is to identify suitable locations for constructing artificial recharge structures in the Kadavanar Sub-basin, South India. People in the Sub-basin mainly depend on the groundwater resources for drinking and irrigation purposes. Groundwater resources are often overexploited in many parts of this Sub-basin to meet the water demand leading to groundwater consumption. A lot of surfaces and sub-surface information and criteria are required for mapping the groundwater recharge zone. This is where the geographic information system [GIS] provides the right impetus besides the groundwater prospective zone to harness multilayered spatial data so that multi-criteria analysis is possible. This analysis integrates historic rainfall data analysis, groundwater level fluctuation, stream network, aquifer thickness, land use/land cover and basin slope. Drainage map, slope map and land use/land cover maps were prepared from satellite imageries. Vertical electrical sounding (VES) geophysical survey with Schlumberger electrode configuration was also conducted in the basin at 50 locations to map the aquifer thickness. Spatial variation maps for groundwater level and aquifer thickness were generated using GIS. Weighted aggregation method was used in this study to obtain groundwater recharge maps. Finally, multi-criteria analysis has been carried out to identify and assess the potential sites for groundwater recharge according to the associated weightages. It is established that GIS is best suited for the mapping of groundwater recharge zones. A similar study can be extended to any other hard-rock region facing water crises.

Occurrence of Uranium in Groundwater from Cuddalore District Tamil Nadu Aided by Geospatial and Statistical Techniques

An attempt has been made to examine uranium distribution in groundwater from Cuddalore district, Tamil Nadu, India. Groundwater occurs under porous sedimentary, fractured, and weathered hard rock formations ranging in age from recent sediments to the oldest Archean formations. A total of 186 groundwater samples were collected during Pre- Monsoon (May) and Post-monsoon (January) and analyzed for major cations, anions, and uranium using standard procedures. Major anions and cations follow the order Cl- >H4SiO4>HCO3- >NO3- > Na+> Ca2+> Mg2+>K+>SO42- > F-> PO43- irrespective of seasons. Uranium in groundwater ranges from 0.1 micro gram per liter (µg/l ) to 24.67 µg/l with average 1.82 µg/l. The spatial representation maps isolated areas of higher and lower uranium and statistical analysis inferred uranium sources to the groundwater environment.

Estimating groundwater inputs from Sankarabarani River Basin, South India to the Bay of Bengal evaluated by Radium (226Ra) and nutrient fluxes

Sankarabarani river basin gains significance due to presence of major industrial, agricultural, urban development and tourist related activities has influenced the water quality in the estuarine environment. Investigations about river water quality has been attempted but not more studies focus about the evaluation of groundwater discharge a significant process that connects groundwater and the coastal seawater have been attempted. For the present study, radium (226Ra) a naturally occurring isotope was measured at three locations and used as effective tracers for estimating the groundwater discharge along with nutrient inputs to the Bay. Groundwater samples representing north east monsoon (December, 2017) has been collected during tidal variation in three locations (Location A- away from the coast towards inland, Location B-intermediate between Location A and the coast and Location C-at the estuary). 226Ra mass balance calculated groundwater fluxes irrespective of tidal variations were 2.27×108 m3/d, 2.19×108 m3/d and 5.22×107m3/d for A, B and C locations respectively. The nutrients like Dissolved inorganic nitrogen (DIN), Dissolved inorganic Phosphate (DIP) and Dissolved Silica (DSi) were found to be influencing the coastal groundwater by contributing fluxes to the sea of about 679.33 T mol/day. The study suggests increasing radium and nutrient fluxes to the Bay altering the coastal ecosystems would result in surplus algal blooms creating hypoxia.