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Farooqui, Anjum
- Middle to Late Holocene Palaeoenvironmental Changes: Evidence from the Sediments, Pollen and Radiocarbon Dates, Adyar, Chennai
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Authors
Affiliations
1 Birbal Sahni Institute of Palaeobatany, 53, University Road, Lucknow - 226 020, IN
2 Centre for Geoscience and Engineering, Anna University, Chennai - 600 090, IN
1 Birbal Sahni Institute of Palaeobatany, 53, University Road, Lucknow - 226 020, IN
2 Centre for Geoscience and Engineering, Anna University, Chennai - 600 090, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No 2 (2006), Pagination: 230-238Abstract
In this paper, we present Middle to Late Holocene chronostratigraphy and palynology data analyzed from three insitu cores - sedimentary profiles retrieved along the Adyar river and the Adyar estuary zone, Chennai. These cores offered excellent cross-sections along the east - west direction. Our data reveals that the mangrove vegetation that existed until Middle Holocene (4180 ±130 Yrs. BP) became extinct since the Late Holocene. The tidal influx influenced the estuary 10 km west inland (at Saidapet) from the present shoreline until Middle Holocene providing congenial environment for mangroves. The reasons for decline in mangroves since the Late Holocene (last 2000 Yrs. BP) is attributed to the relative sea level and coastal configuration change enhanced by the anthropogenic pressure. The palynological evidences from Saidapet (Chennai) and Sulurpet (playa of the Pulicat lagoon) indicate the transgressive phase of middle Holocene in Palar Delta. Although mangroves were abundant during Middle Holocene in both the areas, it faced complete extinction or acutc degradation since the Late Holocene.Keywords
Palynology, Estuarine Sediments, Mangroves, Late Holocene, Coastal changes, Radiocarbon dates, Adyar, Chennai, Tamil Nadu.
- Thecamoebians and Palynological Assemblage in Gautami-Godavari River Mouth, India: Environment and Sea Level Since 3000 Years
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Authors
Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN
2 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN
2 Department of Geology, Andhra University, Visakhapatnam - 530 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 75, No 6 (2010), Pagination: 841-850Abstract
Palaeoclimate and palaeoecological study was carried out using palynological and thecamoebian evidences buried in ∼4 m vertically exposed sediment section (12 km inland from the present shoreline) of Late Holocene age along the banks of Gautami-Godavari River and from three shallow cores from its Nilarevu tributary, Andhra Pradesh. Inferred climatic periods include (1) a basal cold/arid period (∼3000-2000 yrs BP) with dominance of Botryococcus and other fresh water algal remains coupled with abundance of 25 species of thecamoebians indicating shallow and lentic ecosystem during most of the period and (2) a relatively Warm/Wet conditions (since ∼2000 yrs BP) reveal lotic fresh water ecosystem characterized by the evidences of tree palynotaxa and low percentage of thecamoebians. The three shallow cores (0.5 -1 m) near the mouth (∼8 km stretch) of the Nilarevu tributary reveal fluvio-marine deposition in the top 50-80 cm sediment unlike the deeper fresh water depositional environment suggesting sea water ingression in the recent decades. The study illustrates that the Gautami-Godavari River delta gradually prograded since ∼3000 yrs BP until 100-150 yrs unlike the intermittent relative sea level rise and fall recorded during the same period in the contemporary south-east deltaic areas.Keywords
Palynology, Thecamoebians, Gautami-Godavari River, Sea Level, Climate.- Late Pleistocene and Early Holocene Climate of Ny-Alesund, Svalbard (Norway): A Study based on Biological Proxies
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Authors
Vartika Singh
1,
Anjum Farooqui
1,
Naresh C. Mehrotra
1,
Dhruv Sen Singh
2,
Rajni Tewari
1,
Neerja Jha
1,
Ratan Kar
1
Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow – 226 007, IN
2 Centre for Advance Studies in Geology, Lucknow University, Lucknow – 226 007, IN
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow – 226 007, IN
2 Centre for Advance Studies in Geology, Lucknow University, Lucknow – 226 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 78, No 2 (2011), Pagination: 109-116Abstract
Subsurface sediments of a 120 cm deep trench from Ny-Alesund, Svalbard, were analysed for pollenspores and other organic matter contents. This study is supported by two AMS 14C dates (27, 200 yrs BP and 8,762 yrs BP) at the bottom and topmost litho-unit of the trench, respectively. The pollen record provides an evidence of a warm interval at about 27,200 yr BP (Late Weichselian and MIS 3) and cooling episode around 8,762 yr BP. This is also supported by the amount and type of organic matter as well as sediment type and depositional history of the trench sediments.Keywords
Biological Proxies, Trench Section, Late Weichselian, Ny-Alesund, Svalbard.References
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