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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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C. J. Kumanan ¹

Affiliations
1 Centre for Remote Sensing, bharathidasan University, Tiruchrappalli - 23, 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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Pramod Singh ¹, M. G. Yadava ², Malik Z. Ahmad ¹, P. P. Mohapatra ¹, A. H. Laskar ², S. Doradla ¹, J. Saravanavel ³, C. J. Kumanan ³

Affiliations
1 Department of Earth Sciences, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Puducherry 605 014, IN
2 Geoscience Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, IN
3 Centre for Remote Sensing, Bharathidasan University, Khajamalai Campus, Tiruchirappalli 620 023, IN

Abstract

The Cauvery delta encompasses legendary farmlands for at least over the last ~2300 years BP that had supported the growth of the famous Chola and Pandya kingdoms. The chrono-stratigraphic study from six sediment cores taken from the Cauvery basin indicates Holocene evolution of the present delta in response to the past sea-level changes. It is found that at the time of lower sea level during the Last Glacial Maximum, older sediments from the present delta plain, were removed and the extent of removal in different parts was observed to have been controlled by the variation in shelf morphology. Subsequent sealevel rise during the deglaciation after the Last Glacial Maximum, led to filling of the incised valleys with the younger sediments of the Holocene. Nilgiri- Kodaikanal-Palani-Biligirirangan hills granulites and Brahmagiri regions constitute the upper catchment. Geochemistry of the sediments indicates presence of plagioclase and dominance of 2:1 clay, suggesting weathering-limited provenance of southern granulitetype rocks, the source of which is perhaps the high relief and tectonically more active Nilgiri-Kodaikanal- Palani-Biligirirangan hills mountain region rather than the Brahmagiri region. A continuous deposition since the beginning of the Holocene has resulted in the formation of fertile farmlands in the Cauvery delta region.

Keywords

Cauvery, Delta, Farmlands, Holocene Evolution, Sea-Level Change.

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Sm. Ramasamy ¹, J. Saravanavel ¹, C. J. Kumanan ¹, S. Gunasekaran ¹

Affiliations
1 Centre for Remote Sensing, Bharathidasan University, Tiruchirappalli 620 023, IN

Abstract

As the southern part of the Indian Peninsula including the state of Tamil Nadu (TN) (Figure 1 a and b) is a low easterly gradient plain, the rivers that originate from the Western Ghats and the uplands in the west seem to have flowed towards the east with stable dynamics as evidenced from their well-evolved life histories with youthful, mature and old stages. So, the mouths of these river systems provided favourable avenues for ports and the related flourishing maritime activities since historical times. The port city of Poompuhar located at the mouth of River Cauvery in TN was one such a city of glory and had a prominent maritime history attracting traders from several countries (Figure 1).

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S. M. Ramasamy ¹, J. Saravanavel ¹, K. Palanivel ¹, C. J. Kumanan ¹, D. Rajasekhar ²

Affiliations
1 Department of Remote Sensing, Bharathidasan University, Tiruchirappalli 620 023, IN
2 National Institute of Ocean Technology, Velacherry–Tambaram Main Road, Pallikaranai, Chennai 600 100, IN

Abstract

Similar to several ancient coastal/port cities of the world, the Indian subcontinent too had a number of them. The Poompuhar is one such port city established at the mouth of river Cauvery by the Chola dynasty 2000 years ago according to the literature and history. However, while later archaeological studies indicate its spread 20 km along the coast and up to 8 km inside the Bay of Bengal sea, the recent studies indicated its initial establishment over one of the Cauvery’s oldest deltas of 11,000-15,000-year-old at 30 km inside sea and the later shift to the present location. Now, the GEBCO-2019 and MBES based present study revealed the presence of a harbour and related structures in the above delta, resembling 6000-2000- year-old harbours of the world and the knowledge of the people in construction technology and marine environment.

Keywords

Ancient Port City, Offshore Region, Seabed Topography, Submerged Harbour.

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