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

K. K. Ramachandran ¹

Affiliations
1 Centre for Earth Scince Studies Trivandrum, IN

Abstract

No Abstract.

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K. K. Ramachandran ¹

Affiliations
1 Centre for Earth Science Studies, Trivandram - 695 031, IN

Abstract

No Abstract.

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K. K. Ramachandran ¹

Affiliations
1 Marine Science Division, Centre for Earth Science Studies, Akkularn, Trivandrurn 695031, IN

Abstract

Aerial variatron of SiO₂, Al₂O₃, MgO, CaO, TiO₂, K₂O and Na₂O in the Mudbank sediments off Quilandy are discussed. A comparative study of textural classes versus the elemental concentration revealed a size dependence factor on the elemental speciation. Chemical variability depicted from cluster analysis suggests three interrelated elemental groups, such as (I) Al₂O₃, Fe₂O₃, Na₂O and MgO probably controlled by hydrous aluminosilicates in the finer fractions, (2) TiO₂, CaO and SiO₂ with coarser materials especially CaO with shell fragments, (3) lone element K₂O influenced by both hydrous aluminosilicates and feldspars.

Mudbanks are conspicuous with high load suspension. Initial triggering which brought the sediments into suspension is explained in terms of convulsive physical action during the onset of southwest monsoon. It has been found that mudbank sediments are enriched with alumina and ferric oxide. Salinity reduction in the nearshore waters due to monsoonal precipitation is an ideal condition (optimum electrolitic concentration) to defloculate and disperse the sediments into suspension in the presence of phosphate as a natural peptizer. Hence apart from the physical mechanism of suspension, dispersion as a chemical mechanism for the sustenance of suspension is suggested.

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M. Samsuddin ¹, K. K. Ramachandran ¹, G. K. Suchindan ¹

Affiliations
1 Marine Science Division, Centre for Earth Science Studies, P. O. Box No. 7250, Akkulam, Trivandrum, 695 031, IN

Abstract

The cyclicity in the erosional and accretional pattern is monsoon controlled. The erosion during monsoon (May-August) and accretion during pre-monsoon (January-April) and post-monsoon (September-December) are well defined. The transport trends derived from the progressive changes in the grain-size characteristics show relatively better correlation with the measured trends where they are not influenced by the input of sediments from multiple sources. The obliquely approaching swell waves which generate intense northerly longshore currents during non-monsoon season favour accretion of the beaches. The foreshore in the accreted zones are gentler and are characterized by finer and negatively skewed sediments. This zone exhibits a higher period for the breaking waves. The converse is true in the beaches where erosion is prevalent during the monsoon season.

Keywords

Sedimentology, Grain-Size, Sediment Transport, Beach Stability, Kerala Coast.

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M. Samsuddin ¹, K. K. Ramachandran ¹, Y. L. Dora ²

Affiliations
1 Marine Science Division, Centre For Earth Science Studies, Trivandrum 695 031, IN
2 Nagarjuna University, Nagarjuna Nagar 522510, A.P., IN

Abstract

SEM analysis of quartz grain surfaces from the strand plain show many of the characteristic textures that are produced under sub-aqueous environments with second generation features of wind action. It is inferred that the initial stage of deposition of the strand plain sediments was associated with a wave dominated environment. With emergence of this coast, the strand plain sediments were exposed to sub-aerial action, thus registering both sub-aqueous and sub-aerial action features.

Keywords

Sedimentology, Coastal Geomotphology, Kerala Coast.

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