Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

S. M. Ramasamy ¹, Manohar Sinha ¹, C. Devaprasad ¹

Affiliations
1 Geological Survey of India, IN

Abstract

Stress environment of Ishwarakuppam dome area, Cuddapah Basin, has been interpreted through micro-lineament analysis. The strain history suggests deformation under horizontally disposed maximum and least principal stress axes having WNW-ESE and NNE-SSW orientations.

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P. C. Bakliwal ¹, S. M. Ramasamy ¹

Affiliations
1 Geological Survey of India, Jaipur, IN

Abstract

No Abstract.

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S. M. Ramasamy ¹, S. Anbazhagan ¹

Affiliations
1 Centre for Remote Sensing, School of Earth Sciences, Bharathidasan University, Tiruchirappalli - 620 023, IN

Abstract

The present paper narrates how various types of geological. structural, geomorphological and subsurface geological data have been collected and integrated in various pennutations and combinations to select suitable mechanisms for artificial recharge in Ayyar basin of Tamil Nadu.

Keywords

Remote Sensing, Artificial recharge, Groundwater, Tamil Nadu.

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S. Anbazhagan ¹, S. M. Ramasamy ²

Affiliations
1 Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai - 400 076, IN
2 Centre for Remote Sensing, Bharathidasan University, Tiruchirappalli-620 023, IN

Abstract

The paper presents an approach of selecting suitable areas for artificial groundwater recharge structures through remote sensing and integrated terrain analysis by statistical method. The study area "Ayyar basin" is an aquifer system of gneisses and charnockite litho-Units in Tiruchirappalli district, Tamil Nadu. The area has witnessed a steady decline in groundwater table. Hence, the scope for artificial groundwater recharge was studied in this area with the help of Tamil Nadu State Council for Science and Technology (TNSCS&T). Numerical database was generated for water level, lineament density, slope, drainage density, soil type, thickness of soil, thickness of weathered zone, thickness of fractured zone and depth to bedrock through remote sensing and hydrogeological study. These nine variables were used as input parameters and factor analysis with varimax rotation was carried out. In the factor analysis, the factor in which the variables loaded significantly were considered for further analysis. Using factor scores, the domains where the water level was deeper with decrease of slope and drainage density, and increase of lineament density, thickness of soil, thickness of weathered zone, thickness of fractured zone and depth to bedrock were buffered out. The buffered domains derived from each factor were finally integrated and thus the entire study area was fragmented into a number of domains suitable for artificial recharge. Such statistical output has not only helped to identify the suitable locations for artificial recharge but also indicated their controlling terrain characteristics, thus leading to the prioritization of area for specific method of cost effective recharge.

Keywords

Artificial Recharge, Remote Sensing, Lineaments, Statistical Modeling, Ayyar Basin, Tamil Nadu.

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S. M. Ramasamy ¹

Affiliations
1 Centre for Remote Sensing, School of Geosciences Bharathidasan University, Khajamalai Campus, Tiruchirappalli- 620 023, Tamil Nadu, IN

Abstract

Overall geological histories of the Quaternary deltas of all over the world have been studied considerably to understand the evolution, Eustatic-Isostatic changes, Land-Ocean interactive phenomenon, resources, environment etc. But tectonic signatures of these deltas have been less studied, though these have significance in understanding the natural resources, environment and evaluation of natural disasters. In this context, as the state of Tamil Nadu is a low easterly gradient plain, all the easterly flowing rivers have developed well evolved geomorphic features related to youthful, mature and old stages. Such old stages of the rivers are marked by the spectacular development of deltas. These deltas of Tami1 Nadu have been studied in detail for understanding the tectonics with the help of visibly seen tectonic and geomorphic features in satellite based remote sensing and ground based data sets.

The study has revealed that the upper age limit/ages of these deltas are probably of Middle to Late Holocene and the various tectonic and geomorphic anomalies observed in these deltas obviously indicate the tectonic processes/phenomena that prevailed during Middle Holocene-till date. The Proto Cauvery delta of Chennai region is witnessing ongoing NE-SW sinistral, NW-SE dextral and E-W vertical tectonic activities. The streams in Ponnaiyar delta are showing persistent southerly migration due to the probable ongoing land subsidence along NE-SW faults in the southern part of the delta. The Cauvery river which has originally developed a broad Bird-Foot Shaped-Arcuate delta, has undergone a phase of anticlockwise rotational migration and stabilized in the northern rim of the delta as Coleroon river during 2300-750 Y B P due to the ongoing tectonic emergence in the south of the delta almost since the last 6000 years or so. The Vellar river, in deltaic regime, shows northerly migration due to E-W grabening in the northern part of the delta Vaigai and Manimuttar rivers are again migrating northerly in their deltaic regions due to the probable land arching to the south of their present day flow Thus, the paper discusses the post deltaic/Middle-Late Holocene geological processes of Tamil Nadu deltas which are predominated by tectonic activities.

Keywords

Remote Sensing, Holocene Tectonics, Tamil Nadu Deltas.

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S. M. Ramasamy ¹, J. Saravanavel ¹, R. Selvakumar ¹

Affiliations
1 Centre for Remote Sensing, School of Geosciences, Bharathidasan University, Tiruchirappalli - 620 023, IN

Abstract

The Cauvery delta is a major Bird-Root shaped delta with its apex located east of Tiruchirappalli with the mother channel Cauvery flowing along Thanjavur- Kumbakonam - Kaveripoompaitinam. The distributary drainages are radialing over an arc towards east from its apex with a fan shape and finally debouch into the sea from south of Tiruthuraipoondi in the south to Kaveripoompattinam in the north. All these distributary drainages are now seen as palaeochannels including the mother channel Cauvery. which is now called as "Palam Cauvery". The present day flow of Callvery river is confined to the northernmost rim of the delta as river Coleroon. On he basis of the archaeological, epigraphic and historical data analysed earlier and the ¹⁴C dating carried out recently, the present authors infer that the age of the delta may vary from 2300 Y.B.P. (Years Before Present) to 750 Y.B.P. and the age of the palaeochannels are also younging from 2300 Y.B.P. in the south to 750 Y.B.P. in the north. In the southern part of the Cauvery delta, the Mio-Pliocene Sandstone of Pattukottai-Mannargudi area is undergoing upliftment along N-S faults. On the basis of the rapid land progradation during 6085±233 Y.B.P. - 1020±80 Y.B.P. in Vedaranniyam coast, it is visualized that the Mio-Pliocene Sandstone must be undergoing upliftlnenl significantly since 6 100 Y.B.P. onwards. On the basis of the occurrence of older palaeochannels in the south, the gradual younging palaeochannels towards the north and the land emergence in the south of the Cauvery delta in Pattukottai - Mannatgudi area, i t is concluded that the distributary drainages of river Cauvery would have become sequentially defunct/shifted from south to north and linally the mother channel Cauvery also would have been pushed towards north to reach the present tract of Coleroon river. The thinner palaeochannels in the south and the gradual wider palaeochannels in the north of the delta further indicate that as the land was already undergoing emergence in the south even before the river Cauvery had entered into Thanjavur plains, the river could not comfortably spread its distributaries in the south. Hence the southern distributaries, alter a brief flow, would have started drying sequentially from south to north during 2300-750 Y.B.P. thereby the floodwater of each of the southern distributary channel would have been pushed to its successive northern counterpart, i.e. the southern distributary (say 1 ) , pushing its water to its immediate northern counterparl (say 2). then the combined flow of 1 and 2 pushing the water to 3 and so on. The anomalous eyed drainage and its modifications during the last 50-60 years and compressed meanders in Coleroon river. deflected drainages in Palam Cauvery, truncation and punctuation of beach ridges by the E-W faults along the N-S coast and such faults acting as pathways for the sub parallel creeks indicate vibrant Late Holocenc geological history predominated by the tectonic movements in Cauvery delta.

Keywords

Remote Sensing, Geomorphic Anomalies, Post Deltaic Geological Events, Late Holocene Tectonics of Cauvery Delta.

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S. M. Ramasamy ¹, C. J. Kumanan ¹, J. Sakavanavel ¹

Affiliations
1 Centre for Remote Sensing, School of Geosciences, Bharathidasan University, Tiruchirapalli - 620 023, IN

Abstract

No Abstract.

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S. M. Ramasamy ¹, C. J. Kumanan ¹, J. Saravanavel ¹, R. Selvakumar ¹

Affiliations
1 Centre for Remote Sensing, School of Geosciences, Bharathidasan University, Tiruchirappalli-620 023, IN

Abstract

The recent disastrous tsunami of December 26, 2004, has not only alarmed the administrative and the planning machinery to have tsunami mitigation strategies for India, but also signalled the geoscientists to have a deeper look on the phenomenon of tsunami and the vulnerabilities of the Indian coasts. In this context, the authors have conducted a study primarily to evaluate the responses of the coastal geosystems to the tsunami mundations, as it is a very vital component in framing strategies for mitigating the effect of tsunami. The study has revealed that the central coastal parts of Tamil Nadu, namely Cuddalore-Nagapattinam districts, which were worst affected by the recent tsunami, expose a combination of landforms of tectonic, fluvial, fluvio-Marine and marine processes. These different landforms have responded differently to the recent tsunami viz as facilitators, carriers, accommodators, absorbers, barriers etc. On the basis of the same, different eco-Friendly, cost effective and result oriented methods are suggested to mitigate the effects of tsunamis.

Keywords

Coastal Tectonics and Geomorphology, Tsunami Mitigation, Tamil Nadu.

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