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Demarcation of High Mineralization Zones Identified with Respect to Aquifer Type using GIS in and around Vellar Basin, Tamil Nadu, India
K. D. Madhavan
Consultant (Geomatics)
Email: gis_mad@yahoo.co.uk, madhavandhanabalan@yahoo.com
K. D. Madhavan
Consultant (Geomatics)
Email: gis_mad@yahoo.co.uk, madhavandhanabalan@yahoo.com
1 Introduction
The Mineral and Mineral resources is the gift of god. We need natural resources for all our personal needs and development. The State of Tamil nadu locate in the southern fringe of the Indian Peninsular display divergent physiographic provinces such as hill system of Western Ghats in the west, Eastern Ghats in the centre, easterly sloping low gradient plain again in the centre drained by a number of easterly Following River and the deltas and the coastal systems in the east. Because of such divergent physiographic system, the mineral resources and etc., scenario are very divergent and complex in the state of Tamil nadu, especially velar basin. However the scientist here taken up a number of programmes for targeting mineral and other resources. The art of GIS has been the proven technology in mapping all mineral resources and environmental system and also the temporal changes in mineral resources and environment, both due to various morphotechtonic and morphodynamic process. The phenomenal revolution in computer technology has provided such capabilities. Taking advantage of this technologies and also the need, the union government and state government spending substantial part of money in creating computerized data of spatial and non spatial through government and etc., organization. But, we will not go long way in achieving target yielding beneficial rule in the spare of sustainable development through that technoics with this stimulate.
2. Aims and Objective
Generally, Sedimentary rocks are formed either from the solid debris and dissolved mineral matter produced by the mechanical and chemical breakdown of pre-existing rock or, in some cases, from the remains of dead plants and animals. A sedimentary rock may be described accordingly to the type of environment in which it accumulated. A continental deposit is laid down on land (including lakes, rivers etc) by rivers, ice or wind. An intermediate deposit is laid down in an estuary or delta and a marine deposit represents material accumulation on the seashore, in shallow waters of continental shelf or in the deep ocean.
The sedimentary basins like velar multilayered aquifer system is usually dominated by arenaceious and argillaceous formation. As these sediments are buried to depth, several digenetic reactions occur as a result of increasing temperature and pressure, including dissolution of silica, calcite, and iron and clay material. When water moves from one area to other, groundwater dissolves some of the mineral constituent of the rocks it penetrates. The silica freed in a soluble from during weathering is fairly common in ground water. Sandstone and shale chiefly contain residual minerals cemented usually by calcium carbonate, silica, clay or iron oxide. The principal soluble material in these rocks being calcium carbonate, followed by magnesium carbonate, followed by magnesium carbonate, with some magnesium. In argillaceous sediments the water is usually high in dissolved solids, with sulphite and chloride content in excess of bicarbonates. Groundwater in lithified sediment deposits may vary widely from low dissolved solids content in uplands to very high concentrate of over 100,000ppm in deeply buried marine rock. The detailed study in the above line of through carried out for the higher mineralization polluted pockets in the velar basin, Tamil Nadu.
3. Methodology
The following methodology was adopted in the present study,
The area selected for such study to demonstrate the newer concepts of higher mineralization pockets is located near the east cost of Tamil nadu in and around velar basin.
The Present study area Velar basin, of Tamil Nadu state, India, in between Longitude 79Ί15 to 79Ί50 E and Latitude 11Ί05 to 11Ί55. Much importance is associated with this area because of its proximity to southeastern coast of India. Being a tropical area, rainfall distribution is uneven with an annual average rainfall of about 1200mm, received from both southwest and northeast monsoons, and has 37ΊC and 20ΊC as annual average maximum and minimum temperature respectively. The rivers that flow in the study area are Vellar and Ponniyar rivers.
5. Geology of the area
The study area is underlain by formations of Archean to recent age. Crystalline rocks are found on the Western side and Sedimentary formations of Cretaceous, Tertiary and Quaternary ages on the eastern side. The geological map of the area is shown in The Oldest formation is crystalline rocks of Archean age, which comprises charnockites, granite gneisses and pink granites. The Archean and Sedimentary formations are separated by a lineament along NNE SSW direction. The sedimentary formation include Cretaceous and Tertiary deposits consisting of clay, marls, siltstones, alluviate layers of sand and clay (fossiliferous) and the Quaternary alluvium which covers the narrow stretch of coastal area consists of sand, coastal alluvium and backwater lagoon deposits. The Tertiary (Miocene and Pliocene) formations cover a major portion of the study area.
6 Base Data for the year 1990 (DR. Sukija Report)
It has been mentioned that Vellar Ground water basin is quite complex. The basis of selection of the sampling sites has revolved around the main objectives of the study. As one of the main objectives has been to establish the area extent of principal recharge area for the confined aquifer and groundwater flow rate. We have collected a large number of samples from areas, where it is hypothesized that the well might lie in the recharge area. Another important consideration has been given to the discharge area and flow in the upper and lower confined aquifers. Unfortunately, we have very few samples, which may represent the lower confined aquifer. A large number of samples were collected from the I and II mine areas for the observation of spatial-temporal variation. In order to study the aquifer interconnections, samples were collected from different wells tapping different aquifers. A few shallow well samples were also collected in order to compare the groundwater movement with that of deeper aquifers. For regional groundwater flow study, we have utilized the isotope and chemical data for the deeper aquifers, as that has been the main concern of our study. We also have a few collections from some wells, which have shown relatively high chloride waters.
Since, the groundwater samples were collected from different aquifers wherever possible, they are respectively labeled with their tapped aquifers and accordingly classified. Based on such classification the radiocarbon results are discussed as that of
In this context, a uniform scale is very important. It has been decided to generate thematic maps on same scale. Accordingly, the same scales were used for preparation of base map. The basemap details for various themes should be uniform. Adequate ground features, as available on the topomaps were shown on the basemap for facilitation of quick ground references. There are 142 wells analyzed in different aquifer system in Vellar basin (1990). (Shown in fig)
7 Well Locations
Well Locations data were collected from existing NGRI, report. After that the latitude and longitude were marked (Point features) using arc/info software. Nearly 145 wells and have been maintained. The GIS Data base of 142 wells and hydro chemical data editing and labeling and generated using arc/info and arc view softwares.
In the present study, various GIS aquifer databases were generated for the following parameters.
7.1 Total Dissolved Soilds
Total Dissolved Solids mainly various kinds of minerals present in water. In natural water, dissolved solids are mainly composed of Carbonates, Bicarbonates, chlorides, sulphates, phosphates and Nitrates of ca, mg, Na, K, Fe, and Mn.
Concentration of Dissolved solid is an important parameter in drinking water. They given a particular taste to the water at higher concentration and reduce its possibility. Contour maps were prepared for Total Dissolved Solid for Vellar region.
7.2 Chlorides
Chloride, in the form of Chloride ion is one of the Major inorganic anions in water. Chlorides are present in all potable water supplies and in sewage, as a metallic salt. When sodium is present in drinking water, chloride concentrations in excess of 250 mg/l give a salty taste. If the chloride is present as calcium or magnesium salt, the taste detection level may be as high as 1000 mg/l chlorides.
8. Overlaying and classification of zones for high mineralization for aquifer
The thematic maps of each theme are overlaid two at a time to generate a composite map. Thus each layer representing a particular theme is overlaid on other theme to find the intersecting polygons. By this method a new map, showing. The integrated features of two thematic maps is obtained over this composite map is overlaid a third map and so on., so that a final composite map is obtained. Each polygons in the final composite map is associated with a particular set of parameter considered in the study upper confined aquifer in Total dissolved solids, Lower confined aquifer in Total dissolved solids, Upper confined aquifer in Chloride, Lower confined aquifer in Chloride Phreatic aquifer in Chloride and Phreatic aquifer in Total dissolved solids. The Evaluation of each polygon as a potential zone for High Mineralization is based on the added values of scores of various themes.
In the final composite map there are nearly 50 polygons are range into 5 classes each representing a zone namely, Very high, high, Medium, less, and very less. The final thematic map showing the potential zones for high mineralization zone from the fig, it can be seen that the area nearer to the coastal area and inland coastal area are highly mineralization zone.
9. Conclusion
A map showing five different potential zones for high mineralization has been prepared for the Vellar Basin. The final map was prepared by integrating various themes via, upper confined aquifer, lower confined aquifer and Pheratric aquifer such as Chloride, Total dissolved solids. The present study shows the the area having rapid high mineralization in between Neyveli area, vadaelore and chidambaram areas for excellent high mineralization zone. In the study area almost major portion near the coastal and inland to coastal zone are very high minealization zone. In general the eastern parts of the study area are high mineralization favorable zones. High mineralization zone covered in and around Virudachalam, Jayamkondam areas. Moderately and Low mineralization covered in and around vellar basin.
TABLES
Rank, Weight and scores for attributes for various Themes with respect to aquifer:
Reference:
Fig. 1 Study Area Vellar Basin
Fig. 2
Fig. 3
The Mineral and Mineral resources is the gift of god. We need natural resources for all our personal needs and development. The State of Tamil nadu locate in the southern fringe of the Indian Peninsular display divergent physiographic provinces such as hill system of Western Ghats in the west, Eastern Ghats in the centre, easterly sloping low gradient plain again in the centre drained by a number of easterly Following River and the deltas and the coastal systems in the east. Because of such divergent physiographic system, the mineral resources and etc., scenario are very divergent and complex in the state of Tamil nadu, especially velar basin. However the scientist here taken up a number of programmes for targeting mineral and other resources. The art of GIS has been the proven technology in mapping all mineral resources and environmental system and also the temporal changes in mineral resources and environment, both due to various morphotechtonic and morphodynamic process. The phenomenal revolution in computer technology has provided such capabilities. Taking advantage of this technologies and also the need, the union government and state government spending substantial part of money in creating computerized data of spatial and non spatial through government and etc., organization. But, we will not go long way in achieving target yielding beneficial rule in the spare of sustainable development through that technoics with this stimulate.
2. Aims and Objective
Generally, Sedimentary rocks are formed either from the solid debris and dissolved mineral matter produced by the mechanical and chemical breakdown of pre-existing rock or, in some cases, from the remains of dead plants and animals. A sedimentary rock may be described accordingly to the type of environment in which it accumulated. A continental deposit is laid down on land (including lakes, rivers etc) by rivers, ice or wind. An intermediate deposit is laid down in an estuary or delta and a marine deposit represents material accumulation on the seashore, in shallow waters of continental shelf or in the deep ocean.
The sedimentary basins like velar multilayered aquifer system is usually dominated by arenaceious and argillaceous formation. As these sediments are buried to depth, several digenetic reactions occur as a result of increasing temperature and pressure, including dissolution of silica, calcite, and iron and clay material. When water moves from one area to other, groundwater dissolves some of the mineral constituent of the rocks it penetrates. The silica freed in a soluble from during weathering is fairly common in ground water. Sandstone and shale chiefly contain residual minerals cemented usually by calcium carbonate, silica, clay or iron oxide. The principal soluble material in these rocks being calcium carbonate, followed by magnesium carbonate, followed by magnesium carbonate, with some magnesium. In argillaceous sediments the water is usually high in dissolved solids, with sulphite and chloride content in excess of bicarbonates. Groundwater in lithified sediment deposits may vary widely from low dissolved solids content in uplands to very high concentrate of over 100,000ppm in deeply buried marine rock. The detailed study in the above line of through carried out for the higher mineralization polluted pockets in the velar basin, Tamil Nadu.
3. Methodology
The following methodology was adopted in the present study,
- The base map of the study area was prepared using existing Map.
- Using GIS technique, the thematic maps have been prepared.
- Digitizing, Editing & labeling the various thematic maps, Integration and preparation of derived maps using GIS software (Arc/Info)
The area selected for such study to demonstrate the newer concepts of higher mineralization pockets is located near the east cost of Tamil nadu in and around velar basin.
The Present study area Velar basin, of Tamil Nadu state, India, in between Longitude 79Ί15 to 79Ί50 E and Latitude 11Ί05 to 11Ί55. Much importance is associated with this area because of its proximity to southeastern coast of India. Being a tropical area, rainfall distribution is uneven with an annual average rainfall of about 1200mm, received from both southwest and northeast monsoons, and has 37ΊC and 20ΊC as annual average maximum and minimum temperature respectively. The rivers that flow in the study area are Vellar and Ponniyar rivers.
5. Geology of the area
The study area is underlain by formations of Archean to recent age. Crystalline rocks are found on the Western side and Sedimentary formations of Cretaceous, Tertiary and Quaternary ages on the eastern side. The geological map of the area is shown in The Oldest formation is crystalline rocks of Archean age, which comprises charnockites, granite gneisses and pink granites. The Archean and Sedimentary formations are separated by a lineament along NNE SSW direction. The sedimentary formation include Cretaceous and Tertiary deposits consisting of clay, marls, siltstones, alluviate layers of sand and clay (fossiliferous) and the Quaternary alluvium which covers the narrow stretch of coastal area consists of sand, coastal alluvium and backwater lagoon deposits. The Tertiary (Miocene and Pliocene) formations cover a major portion of the study area.
6 Base Data for the year 1990 (DR. Sukija Report)
It has been mentioned that Vellar Ground water basin is quite complex. The basis of selection of the sampling sites has revolved around the main objectives of the study. As one of the main objectives has been to establish the area extent of principal recharge area for the confined aquifer and groundwater flow rate. We have collected a large number of samples from areas, where it is hypothesized that the well might lie in the recharge area. Another important consideration has been given to the discharge area and flow in the upper and lower confined aquifers. Unfortunately, we have very few samples, which may represent the lower confined aquifer. A large number of samples were collected from the I and II mine areas for the observation of spatial-temporal variation. In order to study the aquifer interconnections, samples were collected from different wells tapping different aquifers. A few shallow well samples were also collected in order to compare the groundwater movement with that of deeper aquifers. For regional groundwater flow study, we have utilized the isotope and chemical data for the deeper aquifers, as that has been the main concern of our study. We also have a few collections from some wells, which have shown relatively high chloride waters.
Since, the groundwater samples were collected from different aquifers wherever possible, they are respectively labeled with their tapped aquifers and accordingly classified. Based on such classification the radiocarbon results are discussed as that of
- Phreatic aquifer group
- Semi confined aquifer group
- Upper confined aquifer group
- Lower confined aquifer group.
In this context, a uniform scale is very important. It has been decided to generate thematic maps on same scale. Accordingly, the same scales were used for preparation of base map. The basemap details for various themes should be uniform. Adequate ground features, as available on the topomaps were shown on the basemap for facilitation of quick ground references. There are 142 wells analyzed in different aquifer system in Vellar basin (1990). (Shown in fig)
7 Well Locations
Well Locations data were collected from existing NGRI, report. After that the latitude and longitude were marked (Point features) using arc/info software. Nearly 145 wells and have been maintained. The GIS Data base of 142 wells and hydro chemical data editing and labeling and generated using arc/info and arc view softwares.
In the present study, various GIS aquifer databases were generated for the following parameters.
7.1 Total Dissolved Soilds
Total Dissolved Solids mainly various kinds of minerals present in water. In natural water, dissolved solids are mainly composed of Carbonates, Bicarbonates, chlorides, sulphates, phosphates and Nitrates of ca, mg, Na, K, Fe, and Mn.
Concentration of Dissolved solid is an important parameter in drinking water. They given a particular taste to the water at higher concentration and reduce its possibility. Contour maps were prepared for Total Dissolved Solid for Vellar region.
7.2 Chlorides
Chloride, in the form of Chloride ion is one of the Major inorganic anions in water. Chlorides are present in all potable water supplies and in sewage, as a metallic salt. When sodium is present in drinking water, chloride concentrations in excess of 250 mg/l give a salty taste. If the chloride is present as calcium or magnesium salt, the taste detection level may be as high as 1000 mg/l chlorides.
8. Overlaying and classification of zones for high mineralization for aquifer
The thematic maps of each theme are overlaid two at a time to generate a composite map. Thus each layer representing a particular theme is overlaid on other theme to find the intersecting polygons. By this method a new map, showing. The integrated features of two thematic maps is obtained over this composite map is overlaid a third map and so on., so that a final composite map is obtained. Each polygons in the final composite map is associated with a particular set of parameter considered in the study upper confined aquifer in Total dissolved solids, Lower confined aquifer in Total dissolved solids, Upper confined aquifer in Chloride, Lower confined aquifer in Chloride Phreatic aquifer in Chloride and Phreatic aquifer in Total dissolved solids. The Evaluation of each polygon as a potential zone for High Mineralization is based on the added values of scores of various themes.
In the final composite map there are nearly 50 polygons are range into 5 classes each representing a zone namely, Very high, high, Medium, less, and very less. The final thematic map showing the potential zones for high mineralization zone from the fig, it can be seen that the area nearer to the coastal area and inland coastal area are highly mineralization zone.
9. Conclusion
A map showing five different potential zones for high mineralization has been prepared for the Vellar Basin. The final map was prepared by integrating various themes via, upper confined aquifer, lower confined aquifer and Pheratric aquifer such as Chloride, Total dissolved solids. The present study shows the the area having rapid high mineralization in between Neyveli area, vadaelore and chidambaram areas for excellent high mineralization zone. In the study area almost major portion near the coastal and inland to coastal zone are very high minealization zone. In general the eastern parts of the study area are high mineralization favorable zones. High mineralization zone covered in and around Virudachalam, Jayamkondam areas. Moderately and Low mineralization covered in and around vellar basin.
TABLES
Rank, Weight and scores for attributes for various Themes with respect to aquifer:
| UPPER CONFINED AQUIFER IN CHLORIDE (1990) WEIGHTAGE 4 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 30 101 | 1 | 4 |
| 2 | 101 172 | 2 | 8 |
| 3 | 172 243 | 3 | 12 |
| 4 | 243 314 | 4 | 16 |
| 5 | 314 385 | 5 | 20 |
| UPPER CONFINED AQUIFER TDS(1990) WEIGHTAGE 3 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 190 373 | 1 | 3 |
| 2 | 373 556 | 2 | 6 |
| 3 | 556 739 | 3 | 9 |
| 4 | 739 922 | 4 | 12 |
| 5 | 922 1105 | 5 | 15 |
| LOWER CONFINED AQUIFER IN CHLORIDE (1990) WEIGHTAGE 4 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 0-31 | 1 | 4 |
| 2 | 31- 62 | 2 | 8 |
| 3 | 62 93 | 3 | 12 |
| 4 | 93 124 | 4 | 16 |
| 5 | 124 155 | 5 | 20 |
| LOWER CONFINED AQUIFER IN TDS (1990) WEIGHTAGE 3 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 0 114.7 | 1 | 3 |
| 2 | 114.7 229.401 | 2 | 6 |
| 3 | 229.40344.101 | 3 | 9 |
| 4 | 344.10 458.80 | 4 | 12 |
| 5 | 458.80 573.50 | 5 | 15 |
| PHREATIC CONFINED AQUIFER CL(1990) WEIGHTAGE 4 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 50 1010 | 1 | 4 |
| 2 | 1010 1970 | 2 | 8 |
| 3 | 1970 2930 | 3 | 12 |
| 4 | 2930 3890 | 4 | 16 |
| 5 | 3890 4890 | 5 | 20 |
| PHREATIC CONFINED AQUIFER TDS(1990) WEIGHTAGE 3 | |||
| S.NO | CLASS(mg/L) | RANK | RANKWEIGHT |
| 1 | 50 1760 | 1 | 3 |
| 2 | 1760 3470 | 2 | 6 |
| 3 | 3470 6180 | 3 | 9 |
| 4 | 6180 6890 | 4 | 12 |
| 5 | 6890 8600 | 5 | 15 |
| HIGH MINERALIZATION ZONE (1990) | |||
| S.NO | RANGE | SCORE | |
| 1 | 3 14 | VERY LOW | |
| 2 | 15-25 | LOW | |
| 3 | 26 36 | MEDIUM | |
| 4 | 37 44 | HIGH | |
| 5 | 45 58 | VERY HIGH | |
Reference:
- Anbazhagan S. (1994) Remote sensing based integrated terrain analysis for artificial technology in ayyar basin, Central Tamil nadu, India. Unpublished Ph.d., Thesis, School of Earth Science, Bharathidasan University, Trichy, pp149
- Babu M.N. (2002) Developing internet based geological and mineral Resources information system using Java tools and xml. Proceeding of Geomatics IT enabled spatial data services, sep 18-20,2002, Trichy, Bharathidasan University.
- Burrough P.A.(1986) Principle of Geographical Information for land resources assessment, Clarandone press, Oxford.
- Gribble C.D Rutleys Elements of Mineralogy, 27th edition , CBS publishers and distributors, NewDelhi(1991)
- Jothiprakash V. et all., Delineation of potential zone for artificial recharge using GIS , Journal of the Indian society of Remote Sensing, Vol.31. pp37.
- Parbin Singh A Text book of Engineering and general geology. Katson publishing house, Reprinted with amendment, August 1993.
- Ramasamy SM. Thillai Govindarajan and Balasubramanian T. (1995) Remote Sensing based appropriate methodology for groundwater exploration. A study of Precambrian in south India SM. Ramasamy (Ed.,) in Trends in Geological Remote sensing, Rewat Publishers , pp211-216.
- Selly R.C. An Introduction to sedimentology 2nd edition, academic press, a subsidiary of Harcourt brace javanovich, publishers, London, Newyork(1982)
- Todd D.K. A text book of Groundwater Hydrology.
- Tyrrell G.W The principle of Petrology B.I. Publishers pvt ltd., December (1929)
Fig. 1 Study Area Vellar Basin
Fig. 2
Fig. 3