Vandana Prasad

Vandana Prasad
Birbal Sahni Institute of Palaeobotany

PhD

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61
Publications
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Publications

Publications (61)
Article
We describe Pliocene palynological assemblages from ODP Hole 910C on the Yermak Plateau, Arctic Ocean. Analysis of high-resolution (~10 ± 3 ka) sampling allows us to detect changes in late Pliocene vegetation biomes corresponding to climatic variability between~3.4 to 2.6 Ma. Findings show that a cool temperate and mixed boreal forest (Pinus-Tsuga-...
Conference Paper
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The mid-Pliocene warm period (mPWP) during late Pliocene (3.4-2.6 Ma) epoch coincides with modern global warming trends (CO 2 - 450 ppm). Therefore, the climate-vegetation relationship recorded in the sediments deposited in the Yermak Plateau, marginal Arctic Ocean has potential to understand the global climate warming challenges in the northern he...
Article
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Organic walled dinoflagellate cysts have been utilised to reconstruct paleoclimate and paleoceanographic changes mainly from the temperate and polar region with less attention from the tropics. Information on the dinocyst taxonomy and ecological affinity from the monsoon influenced Northern Indian Ocean is still in infancy. The surface sediments fr...
Article
Marine micropaleontology concerns biostratigraphy for dating and correlation of deep time sequences as well as in palaeoceanography to understand the marine processes of the past. For this, marine micropalaeontology utilizes detailed studies on exclusively marine microbiota such as foraminifers, nannofossils, diatoms, dinoflagellates, and others. T...
Conference Paper
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The marine palynomorphs in twenty-four samples from a 41-39 m thick late Pliocene (3.53 to 2.98 Ma) sedimentary sequence in Ocean Drilling Program (ODP) Hole 910C at the Yermak Plateau in the marginal Arctic Ocean, eastern Fram Strait, have been investigated. Twelve of the samples are from sediments deposited during the mid Piacenzian Warm Period...
Article
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We reviewed the geological record of mangroves based on fossil pollen, fruits, and wood evidence of Nypa, Avicennia, Sonneratia, Rhizophoraceae, and mangrove associates to trace the origin, distribution, extinction, and range contraction of paleo‐mangroves during the Late Cretaceous–Miocene time. Our study region covers paleocoastal areas of Indo‐W...
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A new organic-walled dinoflagellate cyst Cristadinium striatiserratum sp. nov., has been reported from the modern sediments of the northern Indian Ocean. C. striatiserratum sp. nov., exhibit paratabulation in the form of parasutural crests that are septate and possess a serrated distal margin. The autophragm is surmounted with non tabular striations...
Article
Surface sediments in the Vembanad wetland system, southwest India were analyzed for metals. Assessing the extent of metal contamination in Vembanad wetland surface sediments using individual and combined metal pollution indices shows high heterogeneity of sediment characteristics, sources, sedimentary dynamics and geochemical processes and decipher...
Article
Bay of Bengal is a shallow marine basin exposed to seasonal fluctuation in precipitation and run-off. Thus, salinity, temperature, nutrient and productivity vary along the latitudinal and onshore-offshore gradient in the Bay of Bengal. These parameters directly affect primary productivity, including that of dinoflagellate cysts. The spatial distrib...
Article
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Neogene Climate, Terrestrial Mammals and Flora of the Indian Subcontinent
Article
In the above article there is an error in Table 1, page 185. The correct and complete Table is printed below. The publishers would like to apologise for any inconvenience caused. (Table presented).
Article
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Rare earth element (REE) geochemistry of sediments from Vembanad Coastal Wetland, southwest India, shows that light rare earth elements (LREEs) are the more abundant compared to middle rare earth element (MREE) and heavy rare earth element (HREE). We suggest that the textural parameters and the biochemical processes lead to the REE variation in thi...
Article
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Factors controlling the distribution of marine and terrestrial palynomorphs in a coastal ecosystem were studied from surface sediments of 17 stations of Vembanad wetland, Kerala. Marine and terrestrial organic matter, mangrove and terrestrial pollen, dino agellate cysts, diatoms, Total organic carbon, percentage of sand, silt and clay, total disso...
Article
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Dino agellates are one of the major phytoplankton groups of the marine system. The onshore-offshore trends exhibited by dino agellate cysts are important criteria to decipher palaoenvironmental and palaeo-oceanographic changes. Several studies have been carried out on the organic-walled dino agellate cyst distribution pattern in surface sediment...
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This paper presents characteristic modern pollen assemblages in relation to various vegetation types from one of the wettest regions of the world. Four characteristic modern pollen assemblages were recorded based on the major pollen taxa recovered from the surface samples. The Pinus–Tsuga–Betula–Quercus–Rhododendron–Chenopodiaceae assemblage was ob...
Article
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Uddandam P., Rai J., Prasad V., Joshi H. & Nigam R. 2015. Holocene calcareous nannoplanktons from the western continental shelf of Bay of Bengal. Geophytology 45(2): 00-00. Sixty six surface sediment samples from the northern and western Bay of Bengal were analysed for the study of calcareous nannoplanktons. The samples were also studied for the na...
Article
Two mudflat sediment cores collected from a sub-channel (S-61) and the main channel (S-60) of a tropical wetland, along central west coast of India, were investigated for recent changes in depositional environment using geochemical (sediment grain size, total organic carbon, total nitrogen, carbon/nitrogen ratio (TOC/TN), selected metals and pH) an...
Article
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The paper reports palynology and palynofacies studies of lignite-bearing sediments exposed in an opencast mine succession at Surkha, Bhavnagar District, in the coastal region of Gujarat, India. The study examined the relationships between the palynoflora, sedimentary organic matter and environment at the time of deposition of lignite and associated...
Article
A multi-proxy study on the sediments from lower Narmada valley, western India records large flooding events and high sediment influx linked to southwest monsoon variations during late Holocene. On the basis of proxy data and chronology of preserved sediments, three major environmental perturbations at 1809, 1487, and 1187 cal BP have been identifie...
Conference Paper
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Paleoecology, the study of deep time ecological history from sedimentary records, serves as a potential tool to understand patterns, causes, rates and directions of ecological changes due to climatic variability and anthropogenic activities at various temporal scales. This study aims to assess the Holocene paleoecology of the Banni Grassland in Nor...
Article
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A multi-proxy study involving palynology, phytoliths, sedimentology, clay mineralogy, carbon isotopes and magnetic mineralogy was carried out on Wadhwana Lake sediments from sub-humid zone of mainland Gujarat to determine the mid-Holocene climatic fluctuations, and its possible impact on the Harappan culture. The 1.03 m sediment profile of Wadhwana...
Article
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Geological records of early Paleogene warming are rare in low latitudinal regions. The Indian subcontinent preserves records of this global event on western and eastern margins. We attempt to decipher paleoenvironmental setup and facies architecture of the paleo-equatorial early Eocene succession at the Vastan Lignite Mine, Gulf of Cambay, western...
Article
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A multi-proxy study was carried out to address climate–culture relationship from two trenches one each from Kaj and Kanjetar (mid-Saurashtra coast) deposited in a lacustrine setting, since ∼1960 Cal BC and ∼2230 Cal BC, respectively. The salinity of aqueous soil solution (0.1 ppt) and fresh water thecamoebians in both the sites indicate fresh water...
Article
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A 2.8 m thick Holocene sediment succession of Lahuradewa lake, located on the interfluve surface of Ghaghara-Ami rivers, close to the Lahuradewa archaeological site, is studied for phytolith assemblage to reconstruct the palaeoclimate variability during the Holocene. The phytolith morphotypes of grasses (Poaceae) have been used as proxy environment...
Data
A multi-proxy study involving palynology, phytoliths, sedimentology, clay mineralogy, carbon isotopes and magnetic mineralogy was carried out on Wadhwana Lake sediments from sub-humid zone of mainland Gujarat to determine the mid-Holocene climatic fluctuations, and its possible impact on the Harappan culture. The 1.03 m sediment profile of Wadhwana...
Article
Full-text available
Formation of mudbank during summer monsoon and its dissipation during winter is a characteristic feature of the southwest coast of Kerala, South India. Both southwest (SW) and northeast (NE) monsoons play an important role in the overall run-off-related changes and sedimentation pattern in this region that governs the primary productivity in the re...
Article
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In the present write up, a synthesis of the research done in the last four years in vertebrate palaeontology, palynology, ammonoid biostratigraphy and stable isotope geochemistry is presented. SB and GVR discuss the issues relating to Cretaceous-Palaeogene (K-Pg) boundary bioevents in India and their linkage to Deccan volcanism, Jurassic and Cretac...
Article
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The lower part of the early Palaeogene deposits in the Kutch Basin, immediately overlying the Deccan Traps is generally developed as a muddy succession with lignite and rare fossils. Its age has been mostly speculative, based essentially on the age-diagnostic larger foraminiferal fauna in the carbonate horizons present several metres to tens of met...
Article
The Um Sohryngkew section of Meghalaya, NE India, located 800–1000 km from the Deccan volcanic province, is one of the most complete Cretaceous–Tertiary boundary (KTB) transitions worldwide with all defining and supporting criteria present: mass extinction of planktic foraminifera, first appearance of Danian species, δ13C shift, Ir anomaly (12 ppb)...
Article
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Rice and its relatives are a focal point in agricultural and evolutionary science, but a paucity of fossils has obscured their deep-time history. Previously described cuticles with silica bodies (phytoliths) from the Late Cretaceous period (67-65 Ma) of India indicate that, by the latest Cretaceous, the grass family (Poaceae) consisted of members o...
Article
The timing of initiation of continent-continent collision between Asia and India is controversial, but this major tectonic event is generally thought to have occurred in the Early Eocene, ca. 50 Ma. New and independent data from strontium isotopes, stable carbon isotopes, microfossil biostratigraphy, and mammal fossils from an Early Eocene marginal...
Data
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et al. 1 Supplementary Figure S1. Cladogram for the Poaceae. Based on the combined Bayesian phylogenetic analysis of molecular and morphological data using MrBayes. Posterior probability values are shown on nodes. Also illustrated are the placements of the seven fossil calibrations used in the BEAST analyses (letters a – g), the three alternative p...
Data
Full-text available
et al. 1 Supplementary Figure S1. Cladogram for the Poaceae. Based on the combined Bayesian phylogenetic analysis of molecular and morphological data using MrBayes. Posterior probability values are shown on nodes. Also illustrated are the placements of the seven fossil calibrations used in the BEAST analyses (letters a – g), the three alternative p...
Article
Full-text available
Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obtained in different laboratories, each using its own p...
Article
Full-text available
Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obtained in different laboratories, each using its own p...
Article
Full-text available
Equatorial rain forests that maintain a balance between speciation and extinction are hot-spots for studies of biodiversity. Western Ghats in southern India have gained attention due to high tropical biodiversity and endemism in their southern most area. We attempted to track the affinities of the pollen fl ora of the endemic plants of Western Ghat...
Article
Full-text available
Recent advances in Deccan volcanic studies suggest that the main phase of eruptions occurred rapidly over tens of thousands of years near the end of the Maastrichtian (Chenet et al. 2007, 2008) and may have caused the mass extinction as initially discovered in intertrappean sediments exposed in quarries of Rajahmundry, SE India. In these shallow ma...
Article
A study has been carried out to understand benthic foraminiferal and sedimentary organic matter characteristics under low dissolved oxygen conditions off the central west coast of India. Based on the strong correlation between the present-day abundance of rectilinear bi- and triserial benthic foraminifera (RBF) and low dissolved oxygen conditions i...
Article
Full-text available
Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obtained in different laboratories, each using its own p...
Conference Paper
Sedimentological, mineralogical, geochemical, biostratigraphic and paleoecological studies of the Um Sohryngkew Cretaceous-Tertiary (K-T) transition in the Khasi Hills of Meghalaya, India, reveal biotic and environmental changes about 800 km from the Deccan volcanic province (DVP). Upper Cretaceous sediments consist mainly of conglomerates, glaucon...
Article
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The lignite bearing succession (corresponding to Cambay shale) of Vastan lignite mine, Gujarat has been extensively studied in the past few years for its rich vertebrate fauna. However, no age diagnostic fossils with chronological significance are reported. In the present study, several dinoflagellate cysts from different levels in the lignite bear...
Data
Full-text available
Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow-226 007, India [*E-mail-vanprasad@yahoo.co.uk ] Central Arabian Sea region, situated off the Karwar coast, is characterized by intense mid depth (~120-1200 m) oxygen minima zone and shows preservation and accumulation of relatively high organic matter content. Palynofacies analysi...
Article
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The Kothiyakhad sedimentary sequence of Mahi estuary in mainland Gujarat, India, contains valuable information on late- to mid-Holocene climatic conditions as inferred by phytolith, palynofacies, magnetic susceptibility and clay mineralogical studies. Three distinct climatic regimes, ie, Phase I, II and III, were established. Phase I (3660—~3400 yr...
Article
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Phytolith studies were carried out on a 7.8 m profile of mid-late Holocene succession located at Itola, Dhadhar river basin that lies in the sub-humid belt bordering the semi-arid zone of western India. The exposed sediment succession consists of alternating sand, silt and clay with thin layers of terrigenous charcoal partings dated to 3960 ± 510 c...
Article
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Evidence of rice -based agriculture is recorded in the form of phytoliths from about 10 kyrs BP to present succession of Lahuradewa lake deposits, Sant Kabir Nagar district, Ganga Plain. Bulliform phytoliths are considered to be of rice, where distinction between wild rice (Oryza rufipogon) and cultivated rice (Oryza sativa) has been made using the...
Article
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The Upper Cretaceous-Palaeocene rocks of the Khasi Hills, Meghalaya have yielded rich dinoflagellate cysts assemblages recovered from the Mahadeo Formation, the Langpar Formation, lower part of the Therria Formation and lower part of the Sylhet Limestone Formation. Occurrence of several globally recognized marker dinoflagellate cyst taxa, having we...
Article
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Silicified plant tissues (phytoliths) preserved in Late Cretaceous coprolites from India show that at least five taxa from extant grass (Poaceae) subclades were present on the Indian subcontinent during the latest Cretaceous. This taxonomic diversity suggests that crown-group Poaceae had diversified and spread in Gondwana before India became geogra...
Article
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Saxena, R.K., Tripathi, S.K.M. &Prasad, Vandana 1996. Palynoflora! investigation of the Tura Formation(Palaeocene) in Nongwal Bibra area, East Garo Hills, Meghalaya. Geophytology 26(1): 19-31. A palynofloral assemblage, comprising 30 genera and 48 species, has been recorded from the Tura Formation (Palaeocene) exposed in Nongwal Bibra area in East...