Ambili, V; Narayana, A C(Cochin University of Science and Technology, October , 2010)
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Abstract:
Drainage basins are durable geomorphic features that provide insights into the long term evolution of the landscape. River basin geometry develop response to the nature and distribution of uplift and subsidence, the spatial arrangement of lineaments (faults and joints), the relative resistance of different rock types and to climatically influenced hydrological parameters . For developing a drainage basin evolution history, it is necessary to understand physiography, drainage patterns, geomorphic features and its structural control and erosion status. The present study records evidences for active tectonic activities which were found to be responsible for the present day geomorphic set up of the study area since the Western Ghat evolution. A model was developed to explain the evolution of Chaliar River drainage basin based on detailed interpretation of morphometry and genesis of landforms with special emphasis on tectonic geomorphic indices and markers.
Description:
Department of Marine Geology and Geophysics, Cochin University of Science and Technology
Reji,Srinivas; Sajan,K(Department of Marine Geology and Geophysics, School of marine Sciences, 2002)
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Abstract:
In this study, an attempt has been made to find the textural, geochemical, sedimentological characteristics of sediments and water phases of the kayamkulam estuary located in the Southwest coast of Kerala, besides the impact of gas based thermal power plant located at the northern part of the estuary. Estuaries are an important stage in the transport of the solid weathering product of the earth’s crust. These weathered products or sediments are complex mixtures of a number of solid phases that may include clays, silica, organic matter, metal oxides, carbonates, sulfides and a number of minerals. Studies on the aquatic systems revealed the fact that it posses severe ecological impairments due to heavy discharge of sediments from 44 rivers, the continued disposal of pollutants rich materials from industries, sewage channels, agricultural areas and retting yards
Priyalakshmi, G; Dr.Ravindranatha Menon,N(Cochin University of Science and Technology, September , 2008)
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Abstract:
The oceans in their expanse cover, seven - tenths of the Earth surface. Despite being restricted in size, the littoral zone or the intertidal zone (beach) has the greatest variation in environment factors of any marine area .Stemming from this variation ,a treamendous diversity of life, which may be great as or greater than that found in the more extensive sub tidal habits exist in this realm. the study beaches harbour diverse and abundant assemblage of marine organisms. Besides macro funna, microscopic organisms belonging to the lower and higher invertebrate taxa profusely inhabit these beaches. The ecological realm where these animals exist is known as the interstitial environment, which in principle includes the pore spaces in between the sand grains containing copious supply of nutrient rich oxygenated seawater. An astonishing diversity of taxa could be found within the interstitial fauna.
Ramachandran,K K; Dr.Seralathan, P(cusat, April 10, 1992)
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Abstract:
The continental shelf of southwest coast of India (Kerala) is broader and . flatter compared to that of the east coast. The unique characteristic feature of the study area (innershelf between Narakkal and Purakkad) is the intermittent appearance of 'mud banks' at certain locations during southwest monsoon. The strong seasonality manifests significant changes in the wind, waves, currents, rainfall, drainage etc., along this area. Peculiar geomorphological variation with high, mid and lowlands in the narrow strip of the hinterland, the geological formations mainly consisting of rocks of metamorphic origin and the humid tropical weathering conditions play significant role in regulating the shelf sedimentation.
A complementary pattern of distri bution is observed for clay that shows an abundance in the nearshore. Silt, to a major extent, depicts semblance with clay distribution . Summation of the total asymmetry of grain size distribution are inferred from the variation of skewness and kurtosis.Factor I implies a low energy regime where the transportation and deposition phases are controlled mostly by pelagic suspension process as the factor loadings are dominant on finer phi sizes. The second Factor is inferred to be the result of a high energy regime which gives higher loadings on coarser size fractions. The third Factor which might be a transition phase (medium energy regime) representing the resultant flux of coastal circulation of the re-suspension/deposition and an onshoreoffshore advection by reworking and co-deposition of relict and modern sediments. The spatial variations of the energy regime based on the three end-member factor model exhibits high energy zone in the seaward portion transcending to a low energy one towards the coast.From the combined analysis of granulometry and SEM studies, it is concluded that the sandy patches beyond 20 m depth are of relict nature. They are the resultant responses of beach activity during the lower stand of sea level in the Holocene. Re-crystallisation features on the quartz grains indicate that they were exposed to subaerial weathering process subsequent to thei r deposition
Description:
Marine Science Division, Centre for Earth Science Studies,
Thiruvananthapuram