Estd.: 1981
1Department of Geology,
2Department of Applied Geology, University of Madras, Guindy Campus, Chennai-600 025, India
In the present work, the environmental conditions of foraminifera from the core samples of Alamparai Fort in Yedayanthitu Kailiveli mangroves area of Marakkanam estuary, Viluppuram district was studied. The ecological parameters such as sand-silt-clay, calcium carbonate (CaCO3%), organic matter (OM%) and trace element studies were carried out to study the distribution of foraminifera population and mangrove environment. The core was sub-divided into 18 samples. Out of which, 26 foraminifera taxa belonging to 18 genera, 12 families, 8 super families and 4 sub-orders have been identified. The genus Ammonia and Elphidium dominates the total assemblages followed by Quinqueloculina. The species viz., Ammonia beccarii, Ammonia tepida, and E. advenum are widely distributed in all the stations. The species viz., Amphistegina radiate, Cibrononium simplex, Neogloboquadrina dutertrei, Triloculina tricarinata, Helelina anderseni and Cyclifornia contorta are found only in few stations.
The core sediments in the study area are dominated with medium and fine sand. Organic matter ranges from 0.5 to 6%, while CaCO3 ranges from 6.23 to 7.37%. Top of the core is moderately to well sorted (0.70 to 0.657phi), whereas the remaining core (middle to bottom) is moderately well sorted in nature. The silty-sand and sandy-silt are more accommodative substrate for the population of foraminifera. Fe and Cr are predominant elements with minor trace element concentration in this region. Based on foraminifera studies it is observed that the top core up to 30cm show mixing environment, middle core indicates the reducing environment and the bottom core reflects the digenetic environment.
Keywords: Foraminifera, Estuary, Marakkanam, Yedayanthitu Kaliveli, Grain size, Trace elements