eChapters

24. IGNEOUS ROCKS

Introduction : Petros = rocks and logos = science

Petrology means the science of rocks. It deals with the mode of occurrence composition, classification and origin of rocks and their relation to geological processes and history of the earth.

Rocks can be studies in two ways : The study of rocks as specimens in the laboratory is called Petrography which places emphasis on the purely descriptive part from textural mineralogical and chemical point of view. Petrogenesis deals with the origin and processes of formation of rocks. Petrology is a broader term which includes both petrography and petrogenesis.

Igneous rocks are formed by cooling and solidification of magma, either underneath the earth’s surface or above the earth’s surface.

Abstract

An unprecedented tsunami hit the Andaman and Nicobar Islands and the coasts of Andhra Pradesh, Tamil Nadu, Pondicherry and Kerala on the 26^th of December 2004. The loss of life and property, though wide spread in all these areas, was very severe in thickly populated low lying coasts, such as Nagapattinam in Tamil Nadu. Survey of India, in association with the Department of Science and Technology, Govt. of India, New Delhi has taken-up the task of carrying out post-tsunami Mapping of the entire east coast of Tamil Nadu using Digital aerial stereo images acquired immediately after the tsunami. The project aims to generate ortho-rectified photographs on 1: 8000 scale, which are to be used for preparing damage assessment maps of the affected coastal areas. This paper discusses various issues related to Control Surveying, Digital Photogrammetry and Large Scale feature extraction that are involved in the mapping process in general and its credibility for tsunami damage assessment in particular.

Keywords: Tsunami, Digital Photogrammetry, Tsunami damage assessment in India.

9. WEATHERING

The general process of production of rock waste partly by mechanical breaking and partly by chemical decomposition is known as weathering. The resulting products of weathering accumulate in the same place from which they are derived and there is no transport involved in the process.

Agents and types of weathering : The agencies which are involved in the process of weathering are atmosphere, water and organisms. The whole process of weathering may be conveniently divided into two types : mechanical or physical weathering and chemical weathering. Mechanical weathering involves those processes which bring about disintegration of rocks and minerals without any chemical activity. Chemical weathering involves various chemical processes which slowly decompose the rocks and minerals. In nature two processes are intimately associated and only under extreme conditions, they do occur as a separate entities. Mechanical weathering breaks down the rock creating more surface area and facilitates chemical weathering. Chemical weathering weakens the rock and makes it more susceptible to mechanical break down. Thus the two processes are always complementary to each other.

Introduction

India is having very rich sources of inland water bodies in the form of river, lakes and reservoirs. The reservoirs are constructed by impounding the river system. The reservoirs are constructed for effective utilisation of water for irrigation, power generation and flood control. Reservoir fishery in India is also important from socio-economic point of view as it has the potential of providing employment to about two million people, Kaushal and Sharma (2001). Total area under the reservoirs in India is 3:1 million ha and it is expected to double by 2020. This includes 19,000 small reservoirs with a total water surface area of 14,85,557 ha and about 180 medium and 56 large reservoirs of 5,27,541 and 11,40, 268 ha area respectively.

The Maharashtra is endowed with an area of 1,79,430 ha under reservoir and the Maharashtra produces 516 tonnes of fish through reservoirs. The state fisheries corporation was operating in 6,272 ha of reservoirs and marketing the catches.

Abstract

The seaquake on 26^th December 2004 with its epicenter at Sumatra triggered a tsunami, which had a major impact on South East Asian countries. During that incident, the average height of the tsunami wave was 7-10 m and the penetration of seawater was up to 1-1.5 km. The surface water resources meant for irrigation and other drinking purposes got affected by the ingress of seawater in many areas. The direct environmental impacts of the tsunami have more impact along the entire east coast and caused more damages in coastal systems. The physical and chemical perturbations caused in the coastal zone by the tidal waves are discussed. In order to assess the environmental impact on coastal system, it is suggested that significant physical and biogeochemical factors could be framed to quantify the problems.

Keywords: Tsunami, Physical and Chemical Alterations, Coastal zone.

Stress is force per unit area. When matter is subjected to stress; it may undergo changes in size, shape and displacement. Plants are grown in open environment and are likely to experience stress due to environmental conditions or when subjected to pests and diseases. The stress experienced by plants due to environmental conditions is called abiotic stresses. These include stresses caused by weather factors and climatic conditions and include moisture stress and thermal stress. The plants may also experience stress due to strong winds, dryness and as well as humid conditions (Fig.8.1).
The plants are generally classified into three types depending upon the ability to cope up with moisture stress as exhibited by-
• Drought resistance
• Drought tolerance
• Drought adaptations
The moisture stress may be to shortage of Water Compared to its requirements for evapotranspiration and metabolic activities. The plants may also suffer moisture

This chapter introduces plant analysis as a means of determining crop nutrient status and diagnosing nutritional deficiencies. It explains the selection of representative plant tissues at suitable stages of growth, followed by washing, drying, grinding, digestion and elemental estimation. Recommended tissues and sampling stages are provided for cereals, pulses, oilseeds, fibre crops, vegetables, ornamentals and fruit crops. Procedures are included for estimating nitrogen, phosphorus, potassium, sulphur, boron, zinc, iron, copper and manganese in plant samples. The chapter stresses that reliable interpretation depends on correct tissue selection, careful sampling and freedom from contamination. It thereby connects laboratory measurements with crop nutrition and fertilizer management.

Abstract

Jasrota Wildlife Sanctuary (JWS) in Jammu and Kashmir (J&K) Union Territory is floristically less explored. Between 2018 and 2019, field surveys and exploration tours were undertaken to obtain information from local people residing around JWS through open interviews, semi-structured questionnaires and group discussion. Total 113 informants were contacted and data collected by means of ‘snowball method’. A total of 138 species of 60 medicinal plant families were documented subjected to preliminary investigation, which includes 47.10% herbs, 28.26% trees, 19.57% shrubs, 4.35% lianas, and 0.72% parasites. Most dominant families were Fabaceae (11 gen. and 12 spp.), Lamiaceae (6 gen. and 8 spp.), Asteraceae (8 gen. and 8 spp.), Moraceae (2 gen. and 6 spp.), Caesalpinaceae (4 gen. and 6 spp.), Rosaceae (5 gen. and 5 spp.), Euphorbiaceae (4 gen. and 5 spp.), Solanaceae (4 gen. and 4 spp.) and Malvaceae (4 gen. and 4 spp.). Some of the common high valued medicinal plants were Ajuga integrifolia, Aloe barbadensis, Asparagus adscendens, Boerhavia diffusa, Cassia fistula, Lantana camara, Murraya koenigii, Ocimum tenuiflorum, Tinospora cordifolia, Zingiber officinale and several other plants. Traditionally lesser used plants were Abrus precatorius, Acacia catechu, Commelinabenghalensis Cyperus rotundus, Silene vulgaris, Robinia pseudoacacia, Urtica dioica and Ziziphus mauritiana. These medicinal plants are used in treatment of obesity, anti-helminthic, liver infection, diabetes, intestinal infections, rheumatism, tumours, stomachache, insomnia, nerve troubles, skin infection, aphrodisiac, memory related disorders, dermatological problems and asthma. Species with high frequency index should be analyzed for pharmacological research and for discovering of new medicines. It has been observed that lots of medicinal plants grows in this protected area and this sanctuary need proper conservation and management planning.

Abstract

Herbal healthcare forms the most favored system for curing various ailments of the people residing in remote areas of Himalayan region. Gujjar and Bakerwal tribes inhabit the hilly areas of Pir Panjal region of J&K along with their livestock and rely on the surrounding bio-wealth for their healthcare needs. But, proper documentation of traditional knowledge about the medicinal plants has been poorly attempted in this part of J&K. In order to develop a data base of plants being used by Gujjar and Bakerwal tribes of district Poonch, present attempt has been made. The present compilation recorded one hundred forty five plant species belonging to 133 genera and 76 families which are used by the tribal people to cure various ailments like rheumatism, diarrhea, dysentery, skin and gastric problems, wound healing etc. These medicinal plants comprise of 25 trees, 27 shrubs, 82 herbs and 11 climbers. Of the total, 44 species are native to Himalayan region and 101 are non native.

Keywords: Indigenous knowledge, Medicinal plants, Healthcare, Gujjar, Bakerwal

Abstract

The recent earth movements and the related seismicities in the Southern part of the Indian Peninsula has been a matter of enigma for a century and more. While one school was strongly holding the opinion that the southern Indian Peninsula is free from recent earth movements as it is a shield area, the other school has narrated the possibilities for the ongoing earth movements. Under these circumstances, the various anomalies observed from satellite data and ground based information on geomorphology, subsurface lithology, geophysics, hydrogeology, geochemistry etc. have suggested a possible Pleistocene / Holocene graben along Pondicherry in the northeast and Cumbum Valley in the southwest in the southern tip of the Indian Peninsula.

Abstract

The tectonics of the geological past from Archaeozoic to early part of Cenozoic era has been studied due to their penetrative documentation in the form of folds and faults. But the tectonic history of the latter part of the Cenozoic era (i.e Pleistocene period) has remained a matter of conjecture owing to the poor response of the rocks to Pleistocene movements. In the present study the authors presented a model for the Pleistocene earth movements of South India through the study of river migration, coast line changes and lineament fabric derived from the space borne photographs.

In the area of study, the northerly migration of Paleru and Pennar and southerly shift of Palar, Ponnaiyar and Cauvery rivers, marine regressions restricted within this segment and the closely spaced crest line fractures suggest a lineament controlled E-W trending Quaternary upwarping along Mangalore-Madras alignment. Similar E-W cymatogeny is inferred in the southern tip of the Peninsular India on the basis of once again such observations. Such E-W trending Pleistocene arching phenomenon suggests a N-S oriented regional compression which could be related to the collision of Indian plate with Tibetan plate.

ABSORPTION (of light): A process by which light is taken-up by another material. Examples include soot consisting of tiny black particles, which absorb all visible light; and nitrogen dioxide, a pollutant mostly from diesel and gasoline engines, that absorbs blue light resulting in air with a brown tint.

2.1 Introduction

Precipitation is the general term for all forms of moisture emanating from clouds and then ultimately falling on the land surface. It is the total supply of water derived from the atmosphere in the forms of rain, snow, hail, mist, dew, sleet, fog etc. The liquid form of precipitation is called as rainfall whereas the frozen forms of precipitations are snow, hail and sleet. Of all the different forms of precipitation, rain and snow are the two dominant factors that contribute maximum amount of water. In Indian condition, rainfall is the most important form of precipitation that contributes the highest amount of water causing stream flow. Unless otherwise stated, the term rainfall will be used in this book synonymously with precipitation. It is the primary input vector of the hydrologic cycle. Generally it is expressed as the depth water on a horizontal surface over any specified time interval. If the specified time interval is day, then the amount of precipitation is called as daily precipitation. Similarly, the precipitation being contributed over time interval of a month, season and year is termed as monthly, seasonal or annual precipitation. Its form and quantity are influenced by the action of different climatic factors such as wind, temperature and atmospheric pressure. The study of precipitation forms a major portion of the subject of the hydrometeorology.

The major source of water supply on the earth is precipitation. The water received at the earth’s surface from the atmosphere either in solid or liquid form is called precipitation. The water received in solid form may be snow or hail. The precipitation is seasonal in character in many parts of the world. The precipitation may occur due to –
• Conventional physical process
• Orographic effect and
• Convergence of air masses
3.1. Conventional Physical Process
It occurs when the air on the surface of the earth and few metres above the surface of the earth is heated by absorbing long wave radiation emitted by the earth’s surface. As the air is heated, it becomes lighter. The water vapour formed due to evaporation from the soil surface or water bodies will mix with the air and the air will be moist. When the moist air gets heated it becomes lighter and rises vertically upwards. After reaching certain height, the air gets cooled enough to get saturated with water vapour. The moisture in the saturated air will condense on small solid particles to form tiny drops. These solid particles may be dust or smoke or solid particles suspended in the atmosphere and are called aerosols.

Abstract

The social and economic development of any state is interlaced with the manner of its natural resource management. The unplanned use and overexploitation of resources are results in various kinds of land degradation, biomass deterioration and siltation of tanks. In addition, the low per capita availability of land, erratic and uneven distribution of rains, undulating topography, improper management, traditional cropping programmes and recurrence of droughts having cumulative effect leading to low productivity and high risk particularly in dryland farming. Further, developing dry land agriculture through sectoral approach did not bring in the desired results, as the efforts were not integrated. However, in nature all the resources are inter-linked and thus, the integrated developmental approach is the best solution for optimal development of any area. Further, development based on administrative units such as district, taluk, block and village have resulted in imbalance and sometimes, no overall development in some areas. Considering this, natural resources management through Geo- informatics tools like, remote sensing, GIS, GPS and other sensor based techniques are the possible ways for making agriculture sustainable. The paper mainly highlights theimportance of application of latest technologies in agriculture along with some field level case studies.

Keywords: Remote sensing, GIS, Watershed, CAPE, Precision agriculture

Agriculture sector alone uses nearly seventy per cent of fresh water in the world. Therefore, water use economy in the agriculture sector is becoming a necessity. Increasing flood production is possible reducing water used for irrigation if we can adopt precision irrigation (Fig.11.1).
The precision irrigation has to be practiced by providing water to the crop plants in its root zone to meet the water requirements. The precise irrigation can result in-
• Water saving
• Avoid weed control
• Preventing loss of water due to infiltration
• Preventing loss of water due to surface evaporation from the soil
• Minimise salinity problems
• Improving water use efficiency of crops
Traditionally farmers were practicing flood irrigation. It is a method of watering crops delivering to a field and allowing it to flow over the ground among the crops. It is a simple and inexpensive technique followed in less developed areas. Flood irrigation is not very efficient way as nearly 50 per cent of the water applied in the field will be lost through run-off, soil evaporation and other factors. Flood irrigation is only suitable in wet climates and not effective in sandy soils. It leads to water logging in clay soils. There are several types of flood irrigation such as basin, border, furrow and contour irrigation. Although flood irrigation is not very efficient, the water wastage can be avoided to some extent using some techniques

Principle

Standard solutions are the solutions of accurately known concentrations. There are two types of standard solutions viz., primary and secondary.

A known quantity of the substances is dissolved in a volumetric flask and the volume is made upto the mark. Standard solutions prepared in this way are known as primary standard. This method can be used for preparation of standard solutions of substances which satisfy the following conditions.

Principle

Equal volumes of all acids / bases containing their gram equivalent weights per litre of the solution react completely with each other.

More often, if the reagent is not a primary standard, a secondary standard solution must be prepared. The chemical is dissolved and made up or diluted to the desired concentration and then it is standardized against a primary standard or against another reliably known secondary standard solution. Such solutions are called as secondary standard solutions.

ABSTRACT

The chemical characteristics of the groundwater in and around the Valapadi taluk of Salem district have been studied to evaluate the suitability of water for domestic and irrigation uses. Twenty three groundwater samples representing the shallow and deep aquifer of the area were collected and analyzed for pH, TDS, Ca, Mg, Na, K, HCO3, CO3, SO4 and Cl. It is observed that the quality of the groundwater is suitable for domestic use with some exception. The observed high quantity of Cl, SO4 and Mg at some places require immediate attention and detailed study. The value of EC and SAR indicate good to medium q of water for irrigation.