Central Tamil Nadu Research Articles

Mapping and analysis of tectonic lineaments of Pachamalai hills, Tamil Nadu, India using geospatial technology

In the present study an updated tectonic lineament database for Pachamalai hill, a resource-rich hill of central Tamil Nadu state of India has been generated and analysed. Digital Elevation Model generated from CARTOSAT-1 satellite data have been the data source. Lineaments extracted from eight different azimuth angles were compiled together towards the generation of the lineament database, which has been subsequently analysed for their number, length, density and spatial distribution using ArcGIS software. In addition, their orientations were analysed using Rockworks software. Of the 561 lineaments of the study area, about 90% are very short and short lineaments. The total length of the lineaments is 680 sq. km and their density ranges from 0 to 3.4 km/sq. km. The diversely oriented lineaments of the hill reflect the multiple deformation events that have affected the region through geologic time. In about 30% of the hill, the lineament density is high to very high which implies higher degree of deformation, fracturing, shearing and permeability of rocks besides higher soil erodibility and groundwater yield. These high to very high density areas render themselves unsuitable for the construction of dams and reservoirs as the possibility of water leakages into the subsurface, slope and dam failures and rate of sedimentation would be higher. Further, the analysis of the lineaments clearly underlines the need to extract lineaments from different azimuth angles instead of the widely adopted practice of mapping lineaments from single azimuth angle.

Drainage morphometric analysis for assessing form and processes of the watersheds of Pachamalai hills and its adjoinings, Central Tamil Nadu, India

The present study attempts to understand the form and geomorphic/hydrologic processes of the 20 watersheds of the Pachamalai hills and its adjoinings located in Tamil Nadu State of southern India from the analysis of its drainage morphometric characteristics. Survey of India’s topographic sheets of 1:50,000 is the data source from which stream networks and watersheds of the study area were demarcated followed by the analysis of their morphometric characteristics using ArcGIS software. The results of the analysis formed the basis for deducing the form and processes of the watersheds of the study area. The form of the watersheds inferred from the analysis includes shape, length, slope steepness and length, degree of branching of streams, dissection and elongation of watersheds. The geomorphic/hydrologic processes inferred include denudation rate, potential energy, intensity of erosion, mean annual run off, mean discharge, discharge rate, rock resistivity and infiltration potential, amount of sediment transported, mean annual rainfall, rainfall intensity, lagtime, flash flood potential, flood discharge per unit area, sediment yield and speed of the water flow in the streams. The understanding of variations of form and processes mentioned can be used towards prioritizing the watersheds for development, management and conservation planning.

Occurrence of Uranium in Groundwater Along the Lithological Contacts in Central Tamilnadu, India: An Isotope Hydrogeochemical Perspective

Groundwater contributes to the highest exposure level of naturally occurring uranium (U) to biosphere, and hence, the source and concentration of uranium in groundwater needs to be monitored periodically. In the present study, groundwaters from different lithologic locations were collected and measured for uranium concentration and major ions in order to establish any possible link with the lithology on the uranium distribution in central parts of Tamil Nadu, South India. About 11% of the samples contain U in excess of the permissible limit of WHO (Guidelines for drinking-water quality, WHO, Geneva, 2011), and the contamination was limited to mostly hard rock terrain, which is granitic in nature. The correlations among U, major ions, and environmental isotopes were studied to understand the mechanism governing uranium dissolution and transport in groundwater of this region. Observations lead us to infer that the older water with near-neutral pH and oxidizing condition contains higher dissolved U compared with relatively young groundwater. The results also reflect the possible health risk to the local population through long-term consumption of uranium-containing groundwater without any pretreatment.

Yellow Vanda - <I>Vanda spathulata</I>, an Uncommon Orchid from South India

Vanda spathulata (L.) Spreng., the yellow Vanda, found in peninsular India and Sri Lanka, is an unusual species among the vandas. The morphology and ecology of this species collected from the Kolli hills of central Tamil Nadu, is enumerated here along with drawings and photograph.

Assessment of sources for higher Uranium concentration in ground waters of the Central Tamilnadu, India

The uranium concentration in groundwater has attained greater importance considering the health effects in mankind. Groundwater being the major source of uranium; sampling and analysis of groundwater for the major cations and anions along with uranium has been carried out in hard rock aquifers of Madurai district. The sampling has been carried out in varied aquifers like, Charnockites, Hornblende Biotite Gneiss, Granites, Quartzites, Laterites and sandstone. The cation and anions showed the following order of dominance Na+>Ca2+>Mg2+>K+ and that of anions are HCO3->Cl->SO42-> NO3->PO43-. Higher concentration of uranium was found along the granitic aquifers and it varied along the groundwater table condition. Further it was identified that the mineral weathering was the predominant source of U in groundwater. Tritium studies also reveal the fact that the younger waters are more enriched in uranium than the older groundwater with longer residence time.

A study on the impact of weathering in groundwater chemistry of a hard rock aquifer

Hydrogeochemistry of groundwater in hard rock terrain are mainly governed by lithology and land use practices. A study area near Madurai region of central Tamil Nadu was selected with various litho-units and a hard rock sedimentary contact with an unconformity. Land use practices in these regions are also varied with lithology. The study was conducted by collecting 54 groundwater samples spatially covering the major litho-units. Collected samples were analyzed for electrical conductivity, pH, total dissolved solids (TDS), temperature, Ca, Mg, Na, K, Cl, HCO3, NO3, H4SiO4, PO4, and SO4. The results of the samples analyzed found to vary spatially. Dominance of ion shows that the alkalies are predominant and HCO3 is the dominant anion. Piper facies show that the samples are alkali-carbonate type indicating the predominance of weathering. Most of the parameters exceed the drinking water permissible limit. Standard plots and statistical analysis also indicate weathering as the major process governing the hydrogeochemistry of the groundwater in the region. Relative mobility of cations indicates that the rate of liberation of alkalies from the lithology is more prominent.

Coastal Vulnerability Mapping Using Geospatial Technologies in Cuddalore-Pichavaram Coastal Tract, Tamil Nadu, India.

The Eustatic sea level rise due to global warming is predicted to be about 42 to 98cm by 2100 (IPCC 2013) which necessitates identification and protection of vulnerable sections of coasts. The current study area falling in the coastal zone of central Tamil Nadu from Cuddalore in the north and Pichavaram in the south along the southeast coast of India. The study aims in assessing the coastal vulnerability for the Cuddalore-Pichavaram coastal tract since the area is affected more due to 2004 Tsunami, 2008 Nisha and 2011 Thane cyclones using Remote Sensing and GIS tools. Six various terrain and physical parameters such as Geomorphology, Land use/Land cover, coastal slope, Offshore bathymetry, shoreline change (1970-2013), mean Tidal height has been considered to calculate the Coastal Vulnerability Index(CVI) based on USGS classification and they show significant variations all along the coastal tract. Based on the CVI values calculated for the study area the coast is classified as five classes of vulnerability viz., very low, low, moderate, high, very high. The present study can be used as tool for coastal disaster management for future development.

Occurrence of the radionuclides in groundwater of crystalline hard rock regions of central Tamil Nadu, India

A study was conducted to understand the occurrence of the radionuclides in groundwater of crystalline hard rock region. Samples were collected to analyze major cations, anions, U, 222Rn and stable isotopes of oxygen, hydrogen. It was inferred that few samples have U and 222Rn concentrations higher than the permissible limit of drinking water standard. High degree of weathering of granitic rocks and long contact time of groundwater with the aquifer matrix could be the reason for enhanced U and 222Rn levels in groundwater. The association of U with SO4 also proves that there exists anthropogenic influence in groundwater composition.

EXPLORATION OF MEDICINAL PLANTS USED BY THE MALAYALI TRIBES OF KOLLI HILLS, TAMILNADU, INDIA

An Ethno botanical survey was carried out among the ethnic groups in the Kolli hills, Tamil Nadu , India. Kolli Hills or Kolli Malai is a small mountain range located in central Tamil Nadu in Namakkal district of India. The mountains are about 1000 to 1300 m in height and cover an area of approximately 280 km². The present study revealed that the medicinal plants are used to cure skin diseases, stomach problems, diabetes, uri nary infections, fever, cough, cold, snakebites, ear ache, hair growth, headache, indigestion, itches, swellings, wounds and dental problems. Traditional medicinal uses of 60 plants species belonging to the various families were described in this study. The medicinal plant resou rces in Kolli hills continue to play a vital role in healthcare needs of malayali tribal community. The trad itional knowledge of local tribal people on medicinal plants was collected through questionnaires and personal interview of local traditional practitioners during field trips. The elder generation has sound knowledge about medicinal plants. The collection and documentation of their practical knowledge and traditional techniques based on the traditional use of plants is a significant step towards the preservation of the valuable knowledge by keeping in view the fading ethnic t raditions and cultures. From th is study it is obvious that more attention need to be paid to understand and prove the efficacy of traditional knowledge on medicinal plants using advanced scientific tools. Keyword: Ethno botany, Ethno medicine, Kolli hills, antidotes, skin diseases

Seasonal impact on beach morphology and the status of heavy mineral deposition – central Tamil Nadu coast, India

The aim of the present research was to investigate the seasonal impact on nearshore beach dynamics and the status of heavy mineral distribution along central Tamil Nadu coast, India. Beach profile measurements were made in 10 profiling sites between Thirukadaiyur and Velankanni on monthly and seasonal basis from January 2011 to July 2012. Using beach profile data, variation in beach width, slope and volumetric changes have been calculated. Beach slope and nearshore wave parameters were used to quantify the longshore sediment transport rate. Beaches between Thirukadaiyur and Karaikkal attained predominant transport rate in northern direction whereas, the rest of the beaches are in southern direction. The seasonal action of wind and wave currents create nearshore bar during northeast (NE) monsoon and frequent berms at tidal zone during southwest (SW) monsoon. Surface sediment samples were collected in each location for quantifying the heavy mineral weight percentage during the period of pre- and post-Thane cyclone. Sediments were also studied by X-ray diffraction (XRD) to evaluate the changes and occurrence of heavy minerals in beach sands. The XRD results show that sediments in the study area have enriched heavy mineral distribution even after strong cyclonic event. It confirms the redistribution of heavy mineral deposits present in the coast. The results suggested that monsoonal action has influenced the seasonal changes in beach morphology and it does not affect the heavy mineral distribution.

Widespread Earth Tremors in parts of Central Tamil Nadu on 12th August 2011 and its Significance

Abstract The southern part of the Indian Peninsular has started witnessing fast recurring seismicities and earth tremors with the magnitude of 3-5 in the recent years. In this context, the earthquake occurred, with a magnitude of 3.5, east of Ariyalur, Central Tamil Nadu, on 12th August, 2011 is significant. It is because, followed by the earthquake, tremors were felt in over 35-40 villages in an area of 8000 sq km along with the development of cracks and dislocations in buildings in several places. The remote sensing observations showed that while the Ariyalur epicenter is in the eastern Tertiary formations, the tremor felt villages lie in the western crystalline formations. Again the correlation of remote sensing based lineaments with Ariyalur earthquake, the related tremors and also a few past seismic events of the area showed that these epicenters mostly lie along NE-SW lineaments. The tremors related to Ariyalur event were also felt mostly in villages located again in the vicinity of NE-SW lineaments. The lineaments appear to be post collision tectonic grains related to the still on going northerly compressive force due to which only the Indian plate is buckling and fracturing now. Hence the 12th August, 2011 seismic event of Ariyalur cannot be taken as an isolated phenomenon and appears to be related to the Indian plate deformation as a whole. So it calls for in depth studies in the context of fast relapsing seismicities in peninsular India.

Geomatics Based Analysis of Predicted Sea Level Rise and its Impacts in Parts of Tamil Nadu Coast, India

The coastal zones around the world are very densely populated and hence heavily packed with related infrastructures. So, the territorial nations have obvious apprehensions against the IPCC SRES (Intergovernmental Panel on Climate Change, Special Report on Emission Scenario) predicted sea level rise, as it would cause flooding of the low lying coasts and also other related chains of environmental endangers. This has driven these nations to initiate research studies in multiple directions for scientifically evaluating the phenomenon and impacts of sea level rise using all possible technologies including the Geomatics which possesses unique credentials in geosystem mapping. But certain advanced virtues available with Geomatics technology are yet to be capitalized deservingly in this. In addition, almost all the earlier studies have focused only on the impacts of sea level rise (SLR) and not on the predicted shift of high tide line (HTL) and the related inter tidal activities, which would cause a series of environmental disaster. Hence, the present research study was undertaken in a test site of 750 km2 in central Tamil Nadu coast to visualize the areas prone to submergence due to predicted SLR and areas prone to environmental disasters/degradation viz. erosion, deposition, salination of agricultural lands, pollution of aquifers, etc. due to predicted shift of HTL, using digital elevation models derived from SRTM data (Shuttle Radar Topographic Mission), geomorphology and land use/cover maps interpreted using IRS P6 LISS IV satellite data. The paper narrates the certain newer concepts and methodologies adopted in the study and the results.

Pluralism in Indian medicine

When engaging in cross-cultural comparisons, medical anthropology has often tended to employ dichotomous typologies. This results in a reductionist analysis that obliterates the complexities within medical cultures and assimilates them into one homogenous type. This article makes a case for studying the different sources of medical knowledge within the category of ‘Indian medicine’ as they emerge from the differing ontological positions yet intersecting practices of laymen and experts. It goes on to explore the epistemological implications of this pluralism. The article explores the multiple genres of medical knowledge prevalent among people in a region in central Tamil Nadu to examine the relationship between professional, folk and lay practitioners. This analysis shows the complexity of medical knowledge and highlights the inadequacy of established dichotomies.

Coastal Placer Deposits of Central Tamil Nadu, India

ABSTRACT Placer mineral exploration has been undertaken along the beach of Central Tamil Nadu coast from Pondicherry to Vedaranyam. On the basis of the drainage network, geomorphology, and the coastal environment, the study area has been grouped into three sectors, North, Central, and South. Heavy mineral by Wt% shows a slightly higher abundance in the Northern sector, an enrichment of opaques in the Central sector from stations between Poompuhar and Karaikal, and a total depletion in the Southern sector. An abundance of heavies in the Northern sector is considered to be the result of a higher wave energy, and the cymatogenic downwarping of the basin during the present transgression. An enrichment of heavies in the Central sector from Poompuhar to Karaikal is attributable to the reworking of the beach ridges, which were submerged during the present transgression, and to the role of density sorting. A depletion of heavies in the Southern sector is accounted for by the absence of a terrigenous supply and the prevalence of wave shadow conditions throughout the year. The nature of the heavy mineral assemblage reflects the derivation of sediments principally from khondalites, granites, metamorphic rocks and paleo-sediments. Factor analysis also supplements the predominant role of a density factor in the segregation of heavy minerals in the study area. A five-stage model is proposed for the formation of placer deposits in the study region. The present study has disclosed rich concentrations of ilmenites in the central sector between Poompuhar and Karaikal that can be commercially exploited.

Gender ideologies and the formation of rural industrial classes in South India today

Major structural changes are under way today in employment in rural India. There has been a great increase in non-agricultural employment. This case study considers one form of non-agricultural employment, namely rural manufacturing industry in South India. The synthetic gem-cutting industry has been established in central Tamilnadu for decades. However, in the 1990s this rural industry has gone through extremely rapid and significant change. It is argued that this industrial transition is both impacting on, and has in turn been influenced by, rural caste and kinship relations. These transforming relations connect closely with the process of class differentiation that is under way within the various rural social groups who are associated with the industry. Within this context it is argued that two general hypotheses can be made. First, it is argued that the 'working class' is not undifferentiated, but deeply fractured along caste and gender lines. Second, it is claimed that class relations do not always stand as the primary mediator of labour relations: it is shown that for a significant part of the industrial workforce, it is in fact gender ideologies, discourses and practices that mediate labour relations.

The Kumbhabhiseka of an Aiyanar Temple-Complex of Central Tamil Nadu

The Kumbhabhiseka of an Aiyanar Temple-Complex of Central Tamil Nadu