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N. Jayaraju ¹, K. Srinivas ², K. R. Reddi ², I. Suryakumar ³

Affiliations
1 Department of Geology, Sri Venkateswara University, Tirupati-517 502 A.P., IN
2 Department of Geology, Sri Venkateswara University, Tirupati- 517 502 A.P., IN
3 Geonics (India) Pvt. Ltd., 501, Devavrata, Sector-17, Vashi, New Bombay-400 705, IN

Abstract

A total variance explaining 86% of the matrix is consituted by six factors where Florilus-Asterorotalia assemblage (46%) emerged significant. Asterorotalia-Florilus assemblage is more abundant (37%) in monsoon. These faunal assemblages were related to environmental ingredients Viz., texture of sediment substrate, the amount of locked-up organic matter content and bottom water salinity. The cross plot of first two factors for both seasons revealed the common genera found to occur in descending order i.e., Asterorotalia, Florilus, Elphidium and Ammobaculites which are confined especially in normal marine action of sea oscillations are noticed.

Keywords

Palaeontology, Foraminifera, Factor Analysis, East Coast.

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K. Sreenivas ¹, B. N. Raju ¹, Honnappa ², K. R. Reddi ¹

Affiliations
1 Department of Geology, S. V. University College, Tirupati 517502, IN
2 Department of Geology, University of Mysore, Manasa Gangotri, Mysore 570006, IN

Abstract

Thirteen Recent ostracode taxa belonging to 11 genera, 4 families and 1 suborder were identified and illustrated following the classification suggested by Morkhoven (1962-1963) with slight modifications. The species were studied for their distribution. percentage of total shells of species with reference to number of larva, juvenile, adult specimens, male, female ratios, colour pattern and to assess the nature of the estuary and its environs. An attempt has been made to calculate the percentage of biological factor, i.e., predation.

Keywords

Ostracoda, Pulicat Lake, East Coast.

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K. R. Reddi ¹

Affiliations
1 Dept. of Geology, S. V. University, Tirupati-517 502, IN

Abstract

The Pennar River cstuary (N. Lat. 14°33'3"; and 14°6' 13" E.Long. 80°11'54", Fig. 1) sediments were studied seasonally over a period of one year for their organic matter content and its distribution. It is more during monsoonal months than in summer months at the mouth and its increase gradually towards thc upperestuary indicates its derivation is more from the terrestrial sediments than from the sea. A moderate positive correlation has been obtained between organic carbon and organic nitrogen. A rough inverse relationship is noted bctween the organic carbon (or organic nitrogen) and the weight percentage of the fine fraction of the sediments.

Keywords

Sedimentology, Pennarestuary, Andhra Pradesh.

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N Jayaraju ¹, K. R. Reddi ¹

Affiliations
1 Department of Geology, Sri Venkateswara University, Tirupati-517502, IN

Abstract

A total of 180 bottom water and sediment samples each were collected both in monsoon (1990) and premonsoon (1991) periods from coastal and estuarine environments of Kovalam-Kanyakumari Tuticorin, South India. Fifty four benthic foraminiferal taxa were reported belonging to three suborders - Rotalina, Miliolina and Textularina. The fauna was thus related to ecological ingredients viz., salinity, organic matter, calcium and phosphate. Salinity showed an erratic relation whereas other parameters exhibited slight positive bearing with living crop in both the seasons. The living fauna have limited number of taxa with Ammonia beccarii and Asterorotalia dentata being dominant in both the seasons. Faunal density, diversity and distribution increases gradually towards Tuticorin. Inter play of ecological parameters coupled with substrate character could be the reason in faunal abundance and diversity along the east coast. The results lead to the conclusion that the type and size of the substrate is more important in regulating the foraminiferal density and diversity in the study area than mineralogy of the sediment. Investigations reveal that the monsoonal season is more congenial than premonsoonal season to the foraminifera. The provenance of the sediment is a metamorphic terrain dominated by Precambrian gneisses, schists and ferruginous quartzites belonging to Peninsular shield.

Keywords

Foraminifera, Environments, South India.

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N. Jayaraju ¹, K. R. Reddi ¹

Affiliations
1 Department of Geology, Sri Venkateswara University, Tirupati - 517 502, IN

Abstract

Foraminifera, being extremely sensitive to ever changing marine microhabitat and ecosystem, can respond to and amplify even slight monsoonal rainfall fluctuations, particularly, near river mouth. The effect of river discharge on the test morphology of foraminifera has revealed high inertness of rounded symmetrical morpho-group to furious turbulences coupled with enormous fresh water influx. whereas negative trend is noticed with regard to angular-asymmetrical morpho-group. The results could be highly promising in reconstruction of paleomonsoonal history through morpho-group studies in the coastal fringe.

Keywords

Palaeontology, Foraminifera, East Coast, India.

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