Petrology, mineral chemistry and whole-rock geochemistry of the intrusive, layered (>3.1Ga) as well as the extrusive volcanic suites of the Nuggihalli Schist Belt (NSB) are presented in this paper. The dunite-metaperiodotite, serpentinite and syngenetic-stratiform chromite association forms the lower part of the Tagadur ultramafic-mafic complex. The upper part of the intrusion is represented by meta-gabbro-meta-anorthosites with vanadiferous titano-magnetite bodies. The extrusive ultramafic rocks are represented by pillowed, spinifex textured peridotites and high-Mg basalts of komatiitic affinity. Petrological studies of the ultramafic rocks reveal primary cumulus textures exhibited by olivine and chromite and secondary alterations, low-grade metamorphism and deformation. The chromitites hosts a variety, of unusual accessory silicate phases such as corundum, diaspore, rutile, zircon, monazite and baryte in addition to olivine, serpentine and amphibole (anthophyllite), chlorite (clinochlore). Native phases such as gold, silver, copper, iron and tin and other Fe-Ni-Cr-Cu alloys are found associated with cumulus chromite grains in the massive chromitites. Trace and REE geochemistry of these ultramafic-mafic suite reveal significant LREE enrichment and depletion, negative Ce and Eu anomalies and flat to enriched HREE pattern suggestive of their derivation from parental komatiitic magmas by high degree of partial melting of a metasomatized depleted mantle source in a subduction zone environment. Trace element and PGE geochemistry of the chromitites indicate that they are PGE poor chromitites but enriched in Au and other base metal alloys, formed under changing oxidizing and reducing conditions resultant of alteration of the primary sulphides by desulphidation processes during the Mesoarchaean. The associated ultramafic (peridotitic) and mafic (basaltic) komatiites devoid of chromite and PGE represent primitive melts, most probably derived from high degrees of partial melting of a common depleted mantle source.
Geochemical Study of the Ultramafic-Mafic Plutonic and Volcanic Suites of the Nuggihalli Schist Belt, Western Dharwar Craton
₹300.00
Petrology, mineral chemistry and whole-rock geochemistry of the intrusive, layered (>3.1Ga) as well as the extrusive volcanic suites of the Nuggihalli Schist Belt (NSB) are presented in this paper. The dunite-metaperiodotite, serpentinite and syngenetic-stratiform chromite association forms the lower part of the Tagadur ultramafic-mafic complex. The upper part of the intrusion is represented by meta-gabbro-meta-anorthosites with vanadiferous titano-magnetite bodies. The extrusive ultramafic rocks are represented by pillowed, spinifex textured peridotites and high-Mg basalts of komatiitic affinity. Petrological studies of the ultramafic rocks reveal primary cumulus textures exhibited by olivine and chromite and secondary alterations, low-grade metamorphism and deformation. The chromitites hosts a variety, of unusual accessory silicate phases such as corundum, diaspore, rutile, zircon, monazite and baryte in addition to olivine, serpentine and amphibole (anthophyllite), chlorite (clinochlore). Native phases such as gold, silver, copper, iron and tin and other Fe-Ni-Cr-Cu alloys are found associated with cumulus chromite grains in the massive chromitites. Trace and REE geochemistry of these ultramafic-mafic suite reveal significant LREE enrichment and depletion, negative Ce and Eu anomalies and flat to enriched HREE pattern suggestive of their derivation from parental komatiitic magmas by high degree of partial melting of a metasomatized depleted mantle source in a subduction zone environment. Trace element and PGE geochemistry of the chromitites indicate that they are PGE poor chromitites but enriched in Au and other base metal alloys, formed under changing oxidizing and reducing conditions resultant of alteration of the primary sulphides by desulphidation processes during the Mesoarchaean. The associated ultramafic (peridotitic) and mafic (basaltic) komatiites devoid of chromite and PGE represent primitive melts, most probably derived from high degrees of partial melting of a common depleted mantle source.
| Publication Mode |
Online |
|---|---|
| Publication Author |
D. V. Subba Rao, E. V. S. S. K. Babu, V. Balaram, G. Vidyasagar |
| Publication Language |
English |
| Publication Type |
Conference Paper |
| Publication Year |
2014 |
| DOI |
10.17491/cgsi/2014/63393 |
0
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Quality Assessment of Ground Water in Coastal Maharashtra with Special Reference to Sea Water Intrusion
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168754
Palghar, Thane, Raigad, Ratnagiri, Sindhudurg and Greater Mumbai districts of Maharashtra form the Konkan Coastal belt of Maharashtra. In the coastal areas the immediate effect of high groundwater development is often sea water intrusion. Although there were sporadic studies by earlier workers (Umrikar et al., 2007, Gupta et al. 2010) into some reported isolated cases of seawater intrusion in the coastal areas, this has been a maiden attempt to decipher the extent of seawater intrusion in the entire coastal tract of Maharashtra.The area is underlain by Dharwarian meta-sediments (Lower Precambrian age), Deccan Trap lava flows (Upper Cretaceous to Lower Eocene age), Laterites (Pleistocene age) and Coastal alluvial deposits (Recent to Sub-Recent age). Groundwater occurs under phreatic condition in the Coastal and riverine alluvium, laterites and weathered/fractured rocks. The area has been covered by systematic hydrogeological surveys, reappraisal Surveys and groundwater monitoring by CGWB. in these formations depth to water levels range from 0.6 m bgl to 8.07 m bgl. Groundwater is mildly alkaline with pH range of 6.9 to 9.0. Electrical conductivity ranges from 61 to 29370 ?S/cm at 25?C. Only two Samples from Dapoli in Raigad district show EC values higher than 3000 ?S/cm at 25?C. In general, water quality is good and suitable for domestic use and irrigation. In order to confirm the sea water intrusion, ionic ratios like Na:Cl, and Cl:CO3 + HCO3, were computed. From the analysis it is found that about 2 to 10 km wide coastal belt and the inland tidal backwaters are affected by salinity intrusion. It is revealed that about 55% of the analysed samples have indicated salinity ingress. The extent of sea water intrusion is more in the southern part progressively diminishing towards northern area. The maximum effect is observed in Sindhudurg district followed by Ratnagiri, Raigad, Palghar and Greater Mumbai.Over-exploitation of groundwater in pockets and diminishing seaward freshwater flow in the rivers are the major reasons for sea water ingression. Regulation of groundwater development in the coastal area and areas adjacent to estuaries, maintaining adequate stream flow, stopping of riverbed sand mining, construction of tidal regulators at suitable places and creation of fresh water barrier through rainwater harvesting and groundwater recharge are essential to control further sea water intrusion in the area.
Groundwater Scenario, Issues and Management in Arid and Semi-Arid Rajasthan, India
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168772
Drylands of arid Rajasthan are well known for Drought and hot Desert having diversified hydro-geological conditions. Potential aquifer systems include unconsolidated (Quaternaries deposits), semi-consolidated (Tertiary Sandstone, Lathi Sandstone etc.) and fissured consolidated formations. Groundwater level is generally deep especially in western Rajasthan, where it reaches even 150m below land surface. Quality of groundwater is poor in many parts due to geogenic and anthropogenic reasons. Stage of groundwater development in the State is 139.88% with 185 blocks categorized as over-exploited. Groundwater related issues include deep and declining water levels, low groundwater recharge, over-exploitation, drying up of potential aquifer systems, high salinity, fluoride and nitrate concentration, industrial pollution, water logging and lack of appropriate water management. Management options include supply side and demand side measures i.e. water conservation, regulation, protection and especially structural measures for augmentation of resources by large scale artificial recharge of aquifers, for which financial provisions by the Government/incentives to individuals need to be introduced. Scope for artificial recharge of aquifers exists on account of availability of thick permeable geo-formations, deep & declining water levels, and availability of surplus monsoon water in northwest India, which otherwise goes waste flowing to the neighbouring country. Regulatory measures including notification of 35 block areas, mandatory provision for issuance of NOC for industries/ infrastructure/mining projects for controlled groundwater withdrawal. etc. are being taken up by Govt. organizations. State Water Policy is in place and rooftop rainwater harvesting is to be made mandatory for all buildings. State Ground Water Legislation and State Ground Water Authority need to be constituted and regulatory measures be enforced by Rajasthan Government in line with CGWA. There is need for integrated participatory approach of water management. Rajasthan being the most water deficit State in India, deserve to be given ?Special Status for Water Resources? for financial and other purposes by Government of India.
Ground Water Resources of Gujarat: Status of Development, Management Strategy and Policy
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168771
Gujarat State is located in the western part of India, it is well known for entrepreneurship of its peoples. Water resources in the state are very much unevenly distributed. There are very high rainfall areas in the southern part of state, whereas the northern and western parts face desert like climate. Hydrogeologically there are diverse aquifer systems. Some form prolific aquifer system like alluvial formations of North and Central Gujarat plains. There are also hard rock formations like Granites, Deccan Basalts which form poor aquifers. Due to frequent and persistent droughts water resources management has been a challenge in northern and western parts of the state. Total annual availability of water in the state is estimated at 51 BCM/ out of which surface water contribution is 38 BCM, whereas groundwater accounts for 13.58 BCM. The groundwater plays a very important role in agriculture as well as water supply in this drought prone state. The total annual Groundwater Recharge has been assessed as 22.37bcm and Annual Extractable Ground Water Resources as 21.25bcm. The Annual Ground Water extraction has been assessed as 13.58bcm and Stage of Ground Water extraction as 64%. There are 248 assessment units (talukas) out of which 25 Talukas have been categorized as ?Over- exploited?, 5 are ?Critical?, 11 are ?Semi-Critical?,194 as ?Safe? and 13 saline talukas in the state. A well-planned strategy is required for management of water resources in the state. Number of water conservation and augmentation measures have been taken up in the state in the form of Sujalam Suflam Yojna, Sauni Yojna, Participatory irrigation management, ATAL-JAL, Hydrology Project, Interlinking of Rivers to name a few. Further steps suggested for conservation and sustainable use of ground water can be augmentation of groundwater resources through Artificial Recharge, revival of ponds, reuse and recycling of wastewater, protection of water sources from pollution, conjunctive use of surface and ground water, etc
Ground Water Conservation and Artificial Recharge in Madhya Pradesh: A Pragmatic Approach
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168762
The increasing pace of ground water extraction in agricultural, industrial and domestic sectors during the past four decades has led to problems of continuously declining ground water levels and deterioration of groundwater quality in many areas of Madhya Pradesh. This has threatened the sustainability of many dug wells and tube wells. Depending heavily on agriculture-based economy, the State requires assured irrigation for sustainable agricultural productivity. Groundwater is the major source of irrigation, and also the sole source of drinking water. But the development of ground water is constrained due to heterogeneity of the formations, non-uniformity in degree and nature of the weathered and fractured zones of the aquifers. It is observed that there is heavy surface run-off in many areas during the monsoon period often resulting in floods, yet these very same areas face crisis of water during the summer. This flood? drought syndrome is basically resultant of improper management of available water resources. As ground water is an annually replenishable but limited resource, augmentation of the recharge to ground water is the only option left for ensuring its sustainability.The present study is aimed at identifying the areas in Madhya Pradesh suitable for artificial recharge to arrest the depletion of ground water resources on the one hand and create additional resources to cater to the domestic, agricultural and industrial needs in the State.
Ground Water Resources of Chhattisgarh: Resource Potential, Status, Management Issues and Future Strategies
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168764
The Ground Water Resources play an important role in agro-economy of the Chhattisgarh State being heavily dependent on rain?fed agriculture. The Ground water resources are controlled by normal monsoon rainfall of 1201 mm with four aquifer systems, viz a) Sandstone aquifers, b) Limestone aquifers, c) Crystalline aquifers comprising granites, gneisses schists, ultrabasics and basalts of Archean, Proterozoic and Cenozoic age respectively forming discontinuous, unconfined and semi-confined aquifers, and d). Alluvial aquifers comprising alluvium, clays, silts, laterites etc. forming thin and extensive unconfined aquifers in several isolated patches and near major river courses. These are unconsolidated formations of Quaternary age. During pre-monsoon period in the 70% area of the state groundwater level remains under 5 to 10m, 21% under 10 ? 20 m and less than 1% under more than 20 mbgl. In the Post-monsoon period, 71% area shows the groundwater level in the range of 2 to 5 m, 24% area, 5 to 10m and 2% more than 10 m bgl. In general, 23% wells show rise in the range of 0-2m, 35 % 2-4 m and 42%, > 4 m in response to rainfall. Ground water quality is bicarbonate type and suitable for all purposes. Isolated patches of Arsenic, Sulphate, Fluoride and NO3 contamination have also been reported. Ground water meets 84.5 % and 14.5 % of total irrigation and drinking water requirements respectively. The annual ground water recharge has been estimated as 11,579 MCM. The existing ground water extraction for all uses is 4691MCM. Out of 146 blocks, 41 blocks have Stage of Ground Water Extraction < 30 %, 46 blocks, between 30 to 50%, 35 blocks within 50 and 70 % and 24 blocks have > 70%. The groundwater utilization over the years has increased drastically from 5.11 % in 1990 to 44.37% in the year 2017.The immediate attention is needed on (a) Creation of additional Irrigation potential, (b) Supply of contaminant free water through alternate source, (c) Promotion of rainwater harvesting and sartificial recharge with community participation,. (d) Regulation of overuse of ground water and (e) Sensitizing Farmers through incentivizing water efficient irrigation techniques.
Surface Water Scenario in Rajasthan State, India
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168758
Surface water resources in Rajasthan are scarce and scanty owing to hot arid climatic conditions. Major parts of western Rajasthan are devoid of any major drainage system and are reeled under spells of chronic droughts. Average annual rainfall in the state is of the tune of 540mm, decreases westward and is even less than 150mm in the western most parts of Jaisalmer district. Annual Potential evapo-transpiration is also as high as 2060mm in parts of Jaisalmer district. There are 15 river basins in the state. There are also numerous natural as well as artificial freshwater lakes including Pushkar, Rajsamand, Nakki, Ana Sagar, Kayalana, Ramgarh, Foy Sagar etc. mainly in the southern and eastern parts of the state. Salt lakes include Sambhar, Kuchaman, Pachpadra, Didwana, Phalodi, Lunkaransar etc. Indira Gandhi Nahar (IGNP), Bhakara and Gang canals have been constructed to bring Himalayan water to the desert areas of western Rajasthan in addition to other major commands of Chambal, Mahi and Narmada canals etc. In Rajasthan, irrigation projects completed include 22 Major projects, 77 Medium projects, 660 Minor projects and 3139 Tanks have been transferred to Panchyat Raj Department. Usable water is of the magnitude of 16.05 BCM and the Gross Storage Capacity created is of the order of 14.547 BCM. The Live Storage Capacity created is about 11.99 BCM. Out of the total allocated share of 17.88 BCM under interstate water agreement, average annual water availability remains 12.66 BCM due to various climatic, political, institutional or hydrological reasons. In addition to various Central Government Schemes, Watershed schemes and Mukhyamantri Jal Swavlamban Abhiyan are also implemented in the state.
Ground Water Quality of Rajasthan with Special Reference to Fluoride
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168760
Among the challenges faced by the world today in the area of health care, water is the greatest challenge, and this is particularly true for the developing countries. A large proportion of the world?s population relies on ground water as primary source for drinking and domestic use. In recent years, due to increase of population, urbanization, industrialization, use of chemical fertilizers, pesticide in agriculture, there is over increasing threat to surface and ground water quality. The indiscriminate use of ground water for irrigation and other purposes has resulted in sharp decline in ground water table and in changes in the natural geochemistry of ground water. In the largest areal state of the country i.e. Rajasthan higher concentration of all the three hydrochemical parameters viz. salinity, nitrate and fluoride in ground waters have adversely affected the lives of people in general and their socio-economic status in particular. Ground water of western, north-eastern parts of Rajasthan are facing problem of salinity, nitrate and fluoride, whereas central and southern parts are generally facing an acute problem of fluoride. Therefore, immediate action for mitigating the problems at government, semi-government or social levels are required for the welfare of countrymen.
Water Resources Management in India: A Peep Through Ages
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168769
Water is essential for sustenance of life on earth. But the problem is unequal distribution of water in space and time. Ancients developed innovative ways to manage water resources to meet their essential needs like drinking water supplies and irrigation. Many parts of India, especially Rajasthan have been practicing water conservation and rainwater harvesting since historical times. Arwari water shed in Alwar district of Rajasthan has brought to focus traditional techniques of integrated water management with community participation. This paper attempts to briefly present the water management scenario in India since Vedic times.
Water Resources in Goa
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168766
Goa is drained by several rivers like Terekhol, Mandovi, Zuari, etc. and their tributaries, many of which show tidal influence and related saltwater intrusion. The surface water resources of the state have been assessed at about 8570 Mcum with 1465 Mcum utilizable resources (1125 Mcum surface water, 340 Mcum ground water). Presently, surface storages available are to the tune of 335.87 Mcum in the tanks, diversion structures such as bandharas, weirs, etc. The macro level surveys indicate ground water available is to the tune of 43.83 Mcum and utilization is to the tune of 33% which is considered as safe. Major and medium schemes like Salaulim, Tillari, Anjunem and minor irrigation schemes like Chapoli, Panchawadi, and Amthane irrigation projects cater to the agricultural needs of Goa State. The Sal-Amthane, Salauli-Kalay River Inter Linking Projects in Goa augmented the source to a tune of 156 lakh cubic meter. The paper discusses the water requirement and water resources management of Goa by 2051.
Surface Water Resources of Chhattisgarh: An Overview
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168763
The Chhattisgarh state covers a total geographical area of about 135192 Sq. Km with subtropical climate, characterized by extreme summer and moderate winter having average rainfall of about 1300 mm. Physiographically, the area is characterized by three distinct landforms namely Bastar plateau in the South, the plain of Mahanadi river and its tributaries in the central part and the hills of Chhotanagpur plateau in the northern region. The major river basins in the state are Brahmani, Godavari, Ganga, Mahanadi and Narmada . The total catchment of these river basins is about 13559 kilometers. The Mahanadi Basin is the largest basin covering an area of about 76150 square kilometers out of 141589 square kilometers, nearly 4.3 percent of total geographical area of the country. Chhattisgarh has 2 percent population and 3.2 percent of total surface water resources of the country. The utilizable surface potential in the state if properly harnessed can irrigate about 4.3 million hectares area against the existing potential of 1.38 million hectare. Due to various anthropogenic activities, urbanization, industrialization etc, the quality and quantity of water have been adversely affected. The rivers Hasdeo, Indravati, Kharun, Apra etc. are polluted due to industrialization and urbanization in various parts of the Chhattisgarh. To check the pollution, proper management of solid/liquid waste of various industries is needed. Beside these, use of biofertilizers instead of chemical fertilizers, pesticides etc should be promoted. Effective water management strategies combined with watershed treatments like soil conservation, afforestation, desilting of rivers, rainwater harvesting etc are needed to maintain the health of the river basins of Chhattisgarh. The Jal Shakti Abhiyan started by the Government of India is a highly welcome move in this direction.
Sustainable Development and Management of Groundwater of Chhattisgarh: An Overview
Conference Papers, SP-12: Water Resources of Western and Central Regions of India: Status, Issues and Strategies
SKU:
C-168765
In general, Chhattisgarh state is underlain by hard rocks with limited groundwater potentials. But decline of rainfall in most parts of the state is limiting surface water resources too. Agriculture is mostly rainfed, paddy being the main crop in the state. Groundwater is the main source of irrigation and a major source of drinking water. Cavernous limestones/dolomites form the most potential aquifers yielding up to 50 lps as in Bastar, Baloda Bazar and Bilaspur districts. Proposal for construction of energized irrigation dug/bore wells under PMKSY-HKKP-GW scheme in 109 blocks (stage of extraction within 60%) of 7 aspirational districts will enhance ground water irrigation of 7467 ha land. The stage of extraction has already escalated from 5.11% (1990) to 44.43% (2017) which will be escalated further with ongoing and future development programs. The State should undertake conservation of groundwater through regulation, protection and augmentation of the water resources by implementing rainwater harvesting and artificial recharge, along with adoption of rainfed agriculture, drip or sprinkler irrigation, pricing policy for commercial ground water extraction, exploration and planned development of yet unknown aquifers through exploratory drilling aided by remote sensing, geophysics . Based on declining groundwater level trends areas totalling 16,410 sq. km have been demarcated for rainwater harvesting and artificial recharge creating sub-surface ground water storage potential of 1030.11 MCM and an additional irrigation potential of 148430 ha. Further, groundwater pollution from geogenic and anthropogenic sources like high fluoride, arsenic, uranium, sulphate, nitrate as in Rajnandgaon, Durg, Bilaspur, Raipur and Kwardha districts is also a potential threat to the utilisable resources.This paper attempts at a holistic overview of sustainable development and management of ground water resources of the state considering the huge hydrogeological, geophysical and chemical database in the state.
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