Fine resolution palynostratigraphy centred on Chilka Lake is aimed at the reconstruction of history of mangrove vegetation in tidal flat, salt marsh and fresh water wetland environments. Pollen analyses of air catches, lake water, lake bottom mud and surface soil samples have been collectively used to quantify the dispersal and preservation of pollen in relation to the modern vegetation. Pollen analysis of a 5.50 m deep profile from Balugaon at the western flank of the lake in prograded delta zone has been done which provides information about the changes in vegetation and depositional environments from approximately 3,100 radiocarbon years B.P. to the present. The results obtained suggest that (i) air catches are devoid of mangrove taxa instead seasonal non-arboreals and planted trees dominate, (ii) lake water, surface sediments and lake bottom mud samples have recorded the occurrence of both core mangroves and mangrove associates to the extent of 10-33 and 50-83 per cent, respectively, and (iii) Balugaon profile portrays the existence of marine, brackish and fresh water bioassemblages. On the basis of subtle changes in the vegetation, various depositional environments, transgressive and regressive facies have been determined.
This paper presents the result of organic matter analysis from Chilka Lake, Orrisa, India. A co-ordinated attempt has been made to classify and interpret total organic matter (TOM) in relation to the depositional environment. Organo debris analysis dated back to ca 3,200 years B.P. has provided clues that ponding environment gave rise to reducing (anerobic) conditions which probably accelerated microbial activity, transforming the palynodebris into first semi-amorphous/amorphous and then into fine organic matter. Various phases of mangrove vegetation development, the factors responsible for degrading mangals land denudation have also been discussed in the light of multivariate methods of data analysis.
This paper embodies the results of diatom analysis of 54 samples covering all the lithofacies in Hirpur Locality III, Kashmir Valley. Out of 54 samples, only 16 samples have yielded diatoms whereas the rest of the samples proved barren. Diatom analysis has enabled to present two-fold comments: (i) the sediments are poor in diatoms and most of the frustules are ground, and (ii) these sediments are rich in Pennales. Furthermore, the frequency and nature of diatoms in the samples have revealed that the depositional environments were not wholly ponding rather there might have been violent floodings of the lake which perhaps hampered the growth of diatoms and their preservation too.
The paper embodies the results of fine resolution palynostratigraphy of a sediment profile dated 1,500 years B.P. from Dangmal, an area within Bhitarkanika wildlife sanctuary in Cuttack District, Orissa. It is second largest mangrove swamp in India covering an area of 142 sq. km with thickets of mangrove forest. Bhitarkanika is famous for beautiful repository of mangrove constituents wherein 61 species out of the total 67 Indian species exist signifying the mangrove diversity. The bottom samples of profile exhibited rich occurrence of palynodebris such as pollen, spores, diatoms, dinoflagellate cysts, microforaminifera, Pseudoschizaea, etc. The core mangrove taxa encountered are Rhizophora, Heritiera, Sonneratia, Avicennia, Excoecaria, Aegialitis, etc. indicating conducive environment for growth and development of mangroves. However, the frequency of both core and peripheral mangroves declined in the middle and further reduced in the upper part of the profile. It has been found that there was comparatively low degree of mangal exploitation at Dangmal as compared to other investigated areas of Mahanadi Delta, Orissa.
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