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G. J. Chakrapani ¹, V. S. Subramanian ¹

Affiliations
1 School of Environmental Sciences, Jawharlal Nehru University, New Delhi-110067, IN

Abstract

Considering the enormity of sediment load transported by the Mahadnadi river (approximately 15.74∗10⁶ tonnes/year), a,study has been conducted to uncover the groinsize distribution mid clay minerals present in the suspended load which is found to be poorly sorted, mostly fine skewed and very leptokurtic. Increasing water discharge not only increases mean size but improves the sorting of sediments. Sediment size ranges from 1-25 μm and are mostly derived from the sedimentary formations in the basin. Thc Hirakud dam constructed in the Mnhanadi river basin traps coarser scdirnents. Illite is the dotninant clay mineral followed by knolinite, chlorite and montniorillonite. Futher, clays do show preferences to specific size ranges.

Keywords

Sedimentology, Mineralogy, Mahnnadi.

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R. K. Subudhi ¹, G. J. Chakrapani ¹, R. K. Saini ¹

Affiliations
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee - 247 667, IN

Abstract

A number of studies have been carried out and published in recent times on the major elemental compositions and isotopic geochemical aspects on the Ganga River, thus generating a wealth of information. The immense data confirmed the control of Himalayan Rivers, Ganga and Brahmaputra, on changing isotopic signatures of sea waters through geologic time. In a first ever attempt to monitor and study temporal variations in chemical composition of river water, at a particular location in the Ganga River in the Himalayas, we present information collected at a single location of the Ganga River in its initial stages (Rishikesh), studied daily over a four week period during non-monsoon season in the year 2004. The temporal variations in major water quality parameters have been inferred. The variations in chemical compositions at different periods of the day show variations indicating variable chemical weathering rates. The 84 samples collected and analysed for 13 chemical parameters and reported here, have thus generated a strong database for further studies. The variable compositions indicate the dissolution of rocks at different rates and hence there is a strong need to characterize the dissolution rates of various lithologies in river basins.

Keywords

Chemical weathering, Ganga River, Temporal variations, Rishikesh, Himalayas.

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Ravi K. Saini ¹, G. J. Chakrapani ¹, A. K. Sen ¹

Affiliations
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee - 247 667, IN

Abstract

The geochemical characteristics of groundwater in Saharanpur city of Uttar Pradesh have been studied with a set of fifty water samples representing shallow groundwater of the area. The samples were collected during January and April 2003 which represent a season not characterized by excessive precipitation or evaporation. The samples were analyzed for various water quality parameters such as pH, electric conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, sulphate and chloride. Five groundwater samples were analyzed for Sr isotopic composition. The water is mostly Ca-Mg-HCO₃ type and is derived from the carbonate lithology. A few rainwater samples were also analyzed. Chemical weathering process is the dominant factor in the overall water chemistry, however for some parameters like SO₄, industrial effluents and/Or atmospheric precipitation could be a major source. Dominance of carbonate lithology on water chemistry is also observed by the low Sr isotopic ratios (⁸⁷Sr/⁸⁶Sr) in waters. The high carbonate contents could lead to scale formation which is a major problem in the region for domestic and industrial uses of water.

Keywords

Groundwater, Geochemical Study, Saharanpur, Uttar Pradesh.

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A. K. Patra ¹, N. Pendkar ², G. J. Chakrapani ¹

Affiliations
1 Department of Earth Sciences, Indian lnstitute of Technology, Roorkee - 247 667, IN
2 Oil and Natural Gas Commission, Dehra Dun, IN

Abstract

The major objective of the present study has been to determine the mineralogy and chemical composition of sediments of Nainita lake, a major tounst destination situated In the Kumaun Himalayas In the present study, we have determined the mineral content In the sediments of the lake and analysed the associations of toxic metals In various chemical fractions such as, metals which are easily released to water from sediments, and metals bound to carbonates, manganese oxide, iron oxides, organic matter and residual matter Although detrital minerals quartz and feldspar are dominant, calcite, aragonite, illite and gypsum are also present in appreciable quantities Quartz and illlte are the domnant minerals in the coarse fractions of sediments, whereas calcite, aragonite and gypsum are mostly present in finer sediments Among the varrous chemical fractions, most of the metal concentrations are associated with the residual fraction, whereas, organic matter fraction is a major sink for Mn,Z n and Cu Hence, under conditions where organic matter gets oxidized, the metals may be released into the water column, thus resulting In high pollution levels in the lake waters.

Keywords

Heavy metals, Mineralogy, Nainital.

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Sabyasachi Maiti ¹, Narendra K. Meena ¹, Satish J. Sangode ², G. J. Chakrapani ¹

Affiliations
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee 247 667, IN
2 Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehra Dun 248 001, IN

Abstract

An atlas of magnetic anomalies in soils has been prepared for the first time for the city of Delhi, capital of India and one of the most populous and urbanized city in the world. The study reveals that magnetic susceptibility for Delhi top soils (0-15cm) coincide with either industrial sources of pollutants or natural anomalies. The result shows low field mass-Specific susceptiblity value ranging for different observed classes as industrial(3 02 531x10⁵ m³/kg), traffic areas (0 48 100 67 x10⁵ m³/kg) and natural sections (0 02-6 8 xx10⁵ m³/kg). Frequency dependent susceptibility shows quite high median value of 8 67% for older pit samples (depth samples), followed by 5 88% in present (top soils) and lowest for industrial samples (1 67%). The present study is a preliminary investigation on the environmental magnetic studies of soils in Delhi. More detailed rock magnetic studies and assessment of associated contaminations of soils are in progress.

Keywords

Magnetic Susceptibility, Spatial Analysis, Top Soil, Delhi.

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G. J. Chakrapani ¹

Affiliations
1 Department of Earth Science IIT, Roorkee Roorkee 247 667 Uttaranchal, IN

Abstract

No Abstract.

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