Intertidal and freshwater biota have been recovered from four dated estuarine sediment sections, at Calcutta (CV type section), Dum Dum (DI), Barrackpore (BI) and Kolaghat (KI) in the Bengal Basin, India. Five regional palyno-plankton assemblage zones have been established, from four pollen diagrams. These zones are: 1. (I) Heritiera-Bruguiera-Acrostichum aureum-Fern-Ammonia, 2. (II) Avicennia- Sonneratia-Rhizophora-Ceriops-Bruguiera-Fern-Palaeocirrenalia-Ammonia, 3. (III) Ceriops-Bruguiera-Excoecaria-Avicennia-Sonneratia-Heritiera-Typha-Fern-Concentricystes rubinus (Type I), 4. (IV) Heritiera-Bruguiera-Cheno-Amaranthus-Poaceae-Typha-Fern-Concentricystes rubinus (Type I), 5. (V) Potamogeton-Heritiera-Typha-Poaceae-Fern-Gloeotrichia-Concentricystes rubinus (Type). Six environmental phases of deposition are revealed from the regional palyno-plankton assemblage zones. These are: 1. (1) Upland, arid phase characterised by "Kankar" nodule formation. 2. (2) Mixed brackish water and freshwater environment and inundation by seawater (Ammonia transgression) from 7000 to 6500 years B.P. 3. (3) Mangrove swamp with regular inundation (6500 to 6400 years B.P.). 4. (4) Mangrove tidal flat with high precipitation (6400 to 6175 years B.P.). 5. (5) Mixed brackish water/freshwater Heritiera forest and colonisation by non-littoral species (6175 to 5000 years B.P.). 6. (6) Supratidal freshwater swamp from 5000 to 2000 years B.P. and continuing until the present. The significant environmental succession,revealed through the palyno-plankton assemblage zones between 7000 to 2000 years B.P., indicated transgression of the sea between 7000 and 6175 years B.P., causing landward followed by seaward extension of the mangrove ecosystem in the depositional area. © 1990.

P K SEN

M BANERJEE

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Palyno-plankton stratigraphy and environmental changes during the Holocene in the Bengal Basin, India

Review of Palaeobotany and Palynology

Phytoliths have been proved as reliable indicators of an ecosystem's structure in both modern days as well as in the past. Quantitative phytolith studies from modern plants in India are negligible and most of the data comes from grasses excepting few pteridophytes. Data on non-grass angiospermous phytoliths in India is however completely lacking. In order to interpret the fossil phytolith assemblages and their depositional sub-environments from the deltaic Sunderbans, the largest mangrove vegetation of the world, modern analogue is a prerequisite. The objectives of this study are to establish a relationship between modern deltaic non-grass plant communities of the Indian part of the Sunderbans along salinity gradient with their predominant phytolith contents and this study is the first step in identifying the environment associated with mangrove development from phytoliths in ancient sediments and further studies would ascertain which of these phytoliths would survive erosion and burial. Modern phytolith assemblages were studied from different parts of 33 non-grass species representing 27 genera under 23 families collected from different deltaic sub-environments of the study area. Retrieved leaf phytolith assemblages were subjected to Principal Components Analysis and Cluster Analysis. Elemental analysis of some of these morphotypes done using an Energy Dispersive X-ray Spectrometer (EDX) to authenticate chemical composition of some newly described forms of phytoliths. Twenty five phytolith morphotypes identified under light and Scanning Electron microscopes represent a modern reference non-grass phytolith database of deltaic plant communities of the Sunderbans. Extracted morphotypes are described and their taxonomic and environmental implications are interpreted considering quantitative data and statistical analyses. The taxonomic implications of these morphotypes are mostly poor as observed through both Principal Components Analysis and Cluster Analysis except for monocotyledonous and few dicotyledonous families which produce distinctive morphotypes. However, their role in environmental interpretations could be established using this modern phytolith data. The data would provide a basis for identification of deltaic vegetation of an area using non-grass phytoliths.© 2013 Elsevier B.V.

Palaeogeography, Palaeoclimatology, Palaeoecology

Application of non-grass phytoliths in reconstructing deltaic environments: A study from the Indian Sunderbans

A new species of Meliolinites (fossil Meliolales) is described from the Neogene sediments of Darjeeling foothills, West Bengal, India (Lower Siwalik, Gish Clay Formation, Middle Miocene to Upper Miocene). © 2011 J. Cramer in Gebr.

Nova Hedwigia

A new species of Meliolinites (fossil Meliolales) from the neogene sediments of sub-himalayan West Bengal, India

Grasses are among the most abundant, diverse and ecologically important group of plants; their number and diversity make them a significant part of the ecosystem. The characteristic presence of opaline silica in grasses makes them a valuable tool in environmental reconstruction over other groups of vascular plants. Fifty grass taxa belonging to four different subfamilies viz., Panicoideae, Chloridoideae, Ehrhartoideae and Bambusoideae of family Poaceae were collected for phytolith analysis from different eco-vegetational zones viz., swampy mangrove or intertidal mangrove zone, tidal mangrove zone, true mangrove decline zone, zone for colonization of non-littoral species and xerophytic non-mangrove species and dry evergreen forest zone along the coastal regions of the Indian part of the Sunderbans. Predominant phytolith assemblages recovered from these grass taxa might help in discriminating different deltaic sub-environments. It was observed that the dominant grasses of the true mangrove decline zone and the zone for colonization of non-littoral species produced abundant lobate and cross morphotypes. On the other hand, a predominance of flat towers followed by short saddles, three-horned towers, two-horned towers and keeled rondels were noticed in the members of Chloridoideae growing in the xerophytic non-mangrove and dry-evergreen forest zone along riverbanks. In contrast, chloridoid members adapted to the tidal mangrove ridge forest produced spool/horned towers in the highest frequencies followed by ellipsoid rondels and two-horned towers. Grasses exclusively growing on salt marshes of the swampy intertidal mangrove zone showed a dominance of ellipsoid rondel morphotypes followed by flat tower and two-horned towers. The observations were corroborated by the results of principal components analysis (PCA) on modern phytolith data. The result may serve as a basis for the future interpretation of depositional environments of fossil phytolith assemblages recovered from deltaic regions along a salinity gradient. © 2011 Elsevier B.V.

Phytolith assemblages of grasses from the Sunderbans, India and their implications for the reconstruction of deltaic environments

Diverse plant remains recovered from an archaeological site of Chalcolithic-Early Historic age in the Bhairabdanga area of Pakhanna (latitude 23°25′N, longitude 87°23′E), situated on the west bank of the Damodar river, Bankura district, West Bengal, India, include food grains, wood charcoals, and palynomorphs. Radiocarbon dating of the recovered biological remains reveal the age of the site as (3 320 ± 400) to (2 080 ± 80) yr BP. The food grains were identified as Oryza sativa L. and Vigna mungo L, and seeds of Brassica cf. campestris L. were also found; these indicate the agricultural practice and food habits of the ancient people living at Pakhanna from the Chalcolithic to the Early Historic period. Sediments including plant remains have been broadly divided into two zones, considering archaeological findings and radiocarbon dating. Analysis of the plant remains (i.e. wood charcoals and palynomorphs) in addition to cultivated food grains has revealed that a rich vegetation cover existed in this area, with a prevailing tropical and humid climate, comprising the timber-yielding plants Shorea sp., Terminalia sp., and Tamarindus sp., with undergrowths of diverse shrubs and herbs during the Chalcolithic period (zone I) dated (3 320 ± 400) yr BP. Comparatively poorer representation and frequency of plant remains indicate a drier climate during the Early Historic period (zone II) dated as (2 110 ± 340) to (2 080 ± 80) yr BP. Comparisons of the archaeobotanical data recovered from the Chalcolithic and Early Historic period and also a principle components analysis indicate a change in the climate of the area from tropical and humid at (3 320 ± 400) yr BP to tropical and drier conditions at (2 110 ± 340) to (2 080 ± 80) yr BP. The present-day tropical, dry deciduous vegetation of the area suggests that climate change has occurred in the area since the contemporaneous past. The plant remains database has been utilized to reconstruct the settlement pattern of the community living in the site between (3 320 ± 400) and (2 080 ± 80) yr BP. The community settled near the riverbank, practicing cultivation. © 2006 Institute of Botany, Chinese Academy of Sciences.

Journal of Integrative Plant Biology

Plant remains from an archaeological site as indicators of vegetation and agricultural practice between (3 320 Â± 400) and (2 080 Â± 80) yr BP in Gangetic West Bengal, India

Journal	Review of Palaeobotany and Palynology
Publisher	-
ISSN	0034-6667