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Kar, Ratan
- Major Floral Turnover at Mahadeo-Langpar Formational Boundary above K/T Iridium Layer: Is it Facies Controlled?
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Authors
Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN
1 Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow - 226 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No 2 (2006), Pagination: 180-188Abstract
The Um Sohryngkew river section at Therriaghat, Meghalaya, exposes Mahadeo (Maastrichtian) and Langpar (Danian) Formations extensively. The palynological investigation of the topmost Mahadeo and lowermost Langpar reveals an abrupt change in palynoflora at the formational boundary. The Maastrichtian index palynofossils viz. Azolla cretacea, Ariadnaesporites ariadnae, Mulleripollis bolpurensis etc. disappear at the uppermost Mahadeo. At the basal Langpar the assemblage is dominated by fungal and algal elements. On this basis the palynofacies turnover is demarcated within a 40 cm thick calcareous sandy shale underlain by the 3 cm thick highly carbonized shale. The palynological boundary corresponds with the lithological one demarcated by Pandey(1978, 1981), and is located 10 m above the foraminiferal, nannofossil, dinoflagellate boundary approximating the iridium rich level. The palynological data suggest no major catastrophic event at the iridium level with the major taxa continuing through. The major palynological break reported in this paper is at formational boundary and may be facies controlled as well.Keywords
Palynology, Mahadeo-Langpar Formations, Iridium Layer, K/T Boundary, Um Sohryngkew River, Meghalaya.
- Palynological Delimitation of the Coal Bearing Lower Gondwana Sediments in the Southern Part of Tatapani-Ramkola Coalfield, Chattisgarh, India
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Authors
Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226007, IN
1 Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 61, No 5 (2003), Pagination: 557-564Abstract
Coal and carbonaceous shale samples from bore-hole TRSS-1, located in the southern part of Tatapani Ramkola Coalfield have been palynologically analysed. Surface sediments exposed in the vicinity of the bore-hole, along Suknaiya nala, were also examined to ascertain their stratigraphic position vis-a-vis the bor' "oIe sediments. On the basis of quantitative dominance, three assemblage zones have been distinguished. which in ascending order are: (i) Parasaccites-Callumispora palynoassemblage zone, (ii) Scheuringipollenites maxim us palynoassemblage zone and (iii) Faunipollenites-Scheuringipollenites palynoassemblage zone. The first two assemblage zones have been demarcated in bore-hole TRSS-1 and represent Upper Karharbari and Lower Barakar palynozones respectively. The third assemblage zone has been recorded in Suknaiya nala and represents Upper Barakar palynozone.Keywords
Palynology, Gondwana Sediments, Palynomorphs, Assemblage Zones, Tatapani-Ramkola Coalfield, Chattisgarh.- National Conference on Climatic Changes During the Quaternary: Special Reference to Polar Regions and Southern Ocean
Abstract Views :180 |
PDF Views:118
Authors
Rahul Mohan
1,
Ratan Kar
2
Affiliations
1 NCAOR, Goa, IN
2 BSIP, Lucknow, IN
1 NCAOR, Goa, IN
2 BSIP, Lucknow, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 75, No 2 (2010), Pagination: 447-448Abstract
No Abstract.Full Text
- Late Pleistocene and Early Holocene Climate of Ny-Alesund, Svalbard (Norway): A Study based on Biological Proxies
Abstract Views :201 |
PDF Views:2
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
- AHLMANN, H. W. (1953) Glacier variations and climatic fluctuations. New York: Amer. Geog. Soc., Bowman memorial lectures, 51p.
- ALLEY, R.B. and AGUSTSDOTTIR, A.M. (2005) The 8k event: Cause and consequences of a major Holocene abrupt climate change. Quarternary Sci. Rev., v.24, pp.1123-149.
- ALLEY, R.B., MAYEWSKI, P.A., SOWERS, T., STUIVER, M., TAYLOR, K.C. and CLARK, P.U. (1997) Holocene climatic instability: A prominent, widespread event 8200 yr ago, Geology, v.25, pp.483-486.
- ANDERSON, P.M. (1985) Late Quaternary vegetational change in the Kotzebue Sound area, northwestern Alaska. Quarternary Res., v.24, pp.307-321.
- BARBER, D. C., DYKE, A., HILLAIRE-MARCEL, C., JENNINGS, A. E., ANDREWS, J. T., KERWIN, M. W., BILODEAU, G., MCNEELY, R., SOUTHON, J., MOREHEAD, M.D. and GAGNON, J.-M. (1999) Forcing of the cold event of 8,200 years ago by catastrophic drainage of Laurentide lakes, Nature, v.400, pp.344-348.
- BENESTAD, R.E., HANSSEN-BAUER, I., SKAUGEN, T.E. and FORLAND, E.J. (2002) Associations between sea-ice and the local climate on Svalbard. Oslo: Norwegian Meteorological Institute Report No. 07/02, pp.1-7.
- BIRKS, H.H. (2003) The importance of plant macrofossils in the reconstruction of Late glacial vegetation and climate: examples from Scotland, western Norway, and Minnesota, USA. Quarternary Sci. Rev., v.2, pp.454-473.
- BIRKS, H.H. and BIRKS, H.J.B. (2000) Future uses of pollen analysis must include plant macrofossils. Jour. Biogeog., v.27, pp.31- 35.
- CLEMENT, A.C. and PETERSON, L. C. (2008) Mechanisms of abrupt climate change of the last glacial period. Rev. Geophys., v.46, RG4002. doi:10.1029/2006RG000204.
- COMISO, J.C. and PARKINSON, C.L. (2004) Satellite-observed changes in the Arctic. Physics Today, v.57, pp.38-44. doi:10.1063/1.1801866.
- COMISO, J.C., PARKINSON, C.L., GERSTEN, R. and STOCK, L. (2008) Accelerated decline in the Arctic sea ice cover. Geophys. Res. Lett., v.35, No. L01703. doi:10.1029/2007GL031972.
- DANSGAARD, W., JOHNSEN, S.J., CLAUSEN, H.B., DAHL-JENSEN, D., GUNDESTRUP, N. S., HAMMER, C.U., HVIDBERG, C. S., STEFFENSEN, J. P., SVEINBJÖRNSDOTTIR, A.E., JOUZEL, J. and BOND, G. (1993) Evidence for general instability of past climate from a 250-kyr ice-core record, Nature, v.364, pp.218-220.
- EIDE, W. (2003) Plant macrofossils as a terrestrial climate archive for the last 11,000 years in south and central Norway. Ph. D. thesis. University of Bergen, Bergen.
- EPICA COMMUNITY MEMBERS (2006) One-to-one coupling of glacial climate variability in Greenland and Antarctica. Nature, v.444, pp. 195-198.
- FAEGRI, K. and IVERSEN, J. (1989) Textbook of pollen analysis. John Wiley & Sons, Chichester. (Fourth edition, revised by Fægri, K., Kaland, P.E., Krzywinski, K.).
- FREDSKILD, B. and WAGNER, P. (1974) Pollen and fragments of plant tissue in core samples from the Greenland ice cap. Boreas, v.3, pp.105-108.
- GUTHRIE, R.D. (2001) Origins and causes of the mammoth steppe: a story of cloud cover, woolly mammoth tooth pits, buckles, and inside-out Beringia. Quarternary Sci. Rev., v.20, pp. 549- 574.
- HATTESTRAND, M. (2008) Vegetation and climate during Weichselian ice free intervals in northern Sweden: interpretations from fossil and modern pollen records. Ph.D. thesis, Department of Physical Geography and Quaternary Geology, Stockholm University.
- HELAMA, S., LINDHOLM, M., TIMONEN, M., ERONEN, M. (2004) Dendrochronologically dated changes in the limit of pine in northernmost Finland during the past 7.5 millennia. Boreas, v.33, pp.250-259.
- HELMENS, K.F., JOHANSSON, P.W., RASANEN, M.E., ALEXANDERSON, H. and Eskola, K.O. (2007a) Ice-free intervals continuing into Marine Isotope Stage 3 at Sokli in the central area of the Fennoscandian glaciations. Bull. Geol. Soc. Finland, v.79, pp 17-39.
- HELMENS, K.F., BOS, J.A.A., ENGELS, S., VAN MEERBEECK, C.J., BOHNCKE, S.J.P., RENSSEN, H., HEIRI, O., BROOKS, S.J., SEPPÄ, H., BIRKS, H.J. B. and WOHLFARTH, B. (2007b) Present-day temperatures in northern Scandinavia during the Last Glaciation. Geology, v.35, pp.987-990.
- HICKS, S., AMMANN, B., LATALOWA, M., PARDOE, H. and TINSLEY, H. (Eds.), 1996. European Pollen Monitoring Programme: Project description and guidelines. University of Oulu, 28p.
- HICKS, S., TINSLEY, H., PARDOE, H. and CUNDILL, P. (1999) European Pollen Monitoring Programme: supplement to the guidelines. University of Oulu, 4p.
- HOUGHTON, J.T., DING, Y., GRIGGS, D.J., NOGUER, M., VAN DER LINDEN, P.J., DAI, X., MASKELL, K. and JOHNSON, C.A. (2001) Climate change 2001: the scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press, 881 pp.
- HOUMARK-NIELSEN, M., KRUGER, J. and KJÆR, K. (2005) De seneste 150.000 år i Danmark. Geoviden, 2.
- HUMLUN, O., ELBERLING, B., HORMES, A., FJORDHEIM, K., HANNSEN, H.O. and HEINEMEIER, J. (2005) Late-Holocene glacier growth in Svalbard, documented by subglacial relict vegetation and living soil microbes. The Holocene, v.15(3), pp.396-407.
- KNUTTI, R., FLUCKIGER, J., STOCKER, T.F. and Timmermann, A. (2004) Strong hemispheric coupling of glacial climate through freshwater discharge and ocean circulation. Nature, v.430, pp.851-856.
- KONIGSSON, L.-K. (1992) The recent pollen rain in some alpine and sub-alpine environments in the southern parts of the Scandinavian mountains and its bearing on investigations of Holocene forest-line shifts. Acta Bota. Fenni., v.144, pp.19- 34.
- KULLMAN, L. (1995) New and firm evidence for mid-Holocene appearance of Picea abies in the Scandes Mountains, Sweden. Jour. Ecol., v.83, pp.439-447.
- KULLMAN, L. (1996) Norway spruce present in the Scandes Mountains, Sweden at 8000 BP: new light on Holocene tree spread. Glob. Ecol. Biogeog. Lett., v.5, pp.94-101.
- KULLMAN, L. (1998a) The occurrence of thermophilous trees in the Scandes Mountains during the early Holocene: evidence for a diverse tree flora from macroscopic remains. Jour. Ecol., v. 86, pp.421-428.
- KULLMAN, L. (1998b) Non-analogous tree flora in the Scandes Mountains, Sweden, during the early Holocene -macrofossil evidence of rapid geographic spread and response to palaeoclimate. Boreas, v.27, pp.153-161.
- KULLMAN, L. (2000) The geographical history of Picea abies in northern Sweden and adjacent parts of Norway. A contrarian hypothesis of postglacial tree immigrations patterns. Geo-Öko, v. 21, pp.141-172.
- KULLMAN, L. (2001) Immigration of Picea abies into north-central Sweden. New evidence of regional expansion and tree-limit evolution. Nordic Jour. Botany, v.21, pp.39-54.
- LAMB, H.H. (1977) Climate present, past and future. Vol. 2 Climatic history and the future. London: Methuen, 835p.
- LUNKKA, J.P., MURRAY, A. and KORPELA, K. (2008) Weichselian sediment succession at Ruunaa, Finland, indicating a Mid Weichselian ice-free interval in eastern Fennoscandia. Boreas, v.37, pp.234-244.
- MANGERUD, J., DOKKEN, T., HEBBELN, D., HEGGEN, B., INGOLFSON, O., LANDVIK, J.Y., MEJDAHL, V., SVENDSON, J.I. and VORREN, T.O. (1998) Fluctuations of Svalbard-Barents Sea Ice Sheet during the last 150,000 yrs. Quarternary Sci. Rev., v.17, pp.11-42.
- MEIER, W., STROEVE, J., FETTERER, F. and KNOWLES, K. (2005) Reductions in Arctic sea ice cover no longer limited to summer. EOS,Trans., Amer. Geophys. Union, v.86, pp.326- 327.doi:10.1029/2005EO360003.
- PELTO, M.S., HIGGINS, S.M., HUGHES, T.J. and FASTOOK, J.L. (1990) Modelling mass-balance changes during a glaciations cycle. Anna. Glaci., v.14, pp.238-241.
- RIGOR, I.G., and WALLACE, J.M. (2004) Variations in the age of Arctic sea-ice and summer sea ice extent. Geophys. Res. Lett., v.31: No. L09401. doi:10.1029/2004GL019492.
- SCHWEGER, C.E. (1982) Late Pleistocene vegetation of eastern Beringia: pollen analysis of dated alluvium. In: D.M. Hopkins, J.V. Matthews, C. E. Schweger Jr and S.B. Young Paleoecology of Beringia (Eds.), Academic Press, New York, pp.95-112.
- SERREZE, M.C., WALSH, J.E., CHAPIN, F.S. III, OSTERKAMP, T., DYURGEROV, M. and ROMANOVSKY, V. (2000) Observational evidence of recent change in the northern high-latitude environment. Climatic Change, v.46, pp.159-207. doi:10.1023/A:1005504031923.
- SERREZE, M.C., MASLANIK, J.A., SCAMBOS, T.A., FETTERER, F., STROEVE, J., KNOWLES, K.(2003) A record minimum arctic sea ice extent and area in 2002. Geophys. Res. Lett., v.30, No.1110, doi:10.1029/2002GL016406.
- STROEVE, J., SERREZE, M., DROBOT, S., GEARHEARD, S., HOLLAND, M., MASLANIK, J., MEIER, W. and SCAMBOS, T. (2008) Arctic sea ice extent plummets in 2007. EOS, Trans. Amer. Geophys. Union, v.89, pp.13-20. doi:10.1029/2008EO020001.
- TELLER, J.T. and LEVERINGTON, D.W. (2004) Glacial Lake Agassiz: A 5000 yr history of change and its relationship to the d18O record of Greenland. Geol. Soc. Amer. Bull., v.116, pp.729- 742.
- UKKONEN, P., ARPPE, L., HOUMARK-NIELSEN, M., KJAER, K.H. and KARHU, J.A. (2007) MIS 3 mammoth remains from Swedenimplications for faunal history, palaeoclimate and glaciations history. Quarternary Sci. Rev., v.26, pp.3081-3098.
- VAN MEERBEECK, C.J., RENSSEN, H. and ROCHE, D.M. (2009) How did Marine Isotope Stage 3 and Last Glacial Maximum climates differ? - Perspectives from equilibrium simulations. Clim. Past, v.5, pp.33-51.
- WALKER, D.A. (2000) Hierarchical subdivision of Arctic tundra based on vegetation response to climate, parent material and topography. Glob. Change Biol., v.6, pp.19- 34.
- WOHLFARTH, B. (2009) Report Ice-free conditions in Fennoscandia during Marine Oxygen Isotope Stage 3? Technical Report TR- 09-12, Department of Geology and Geochemistry, Stockholm University, April 2009.