Geochemical Characteristics of Mudbank Environment - A Case Study from Quilandy, West Coast of India

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.