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| Davies, Siwan M.; Abbott, Peter M.; Meara, Rhian H.; Pearce, Nicholas J. G.; Austin, William E. N.; Chapman, Mark R.; Svensson, Anders; Bigler, Matthias; Rasmussen, Tine L.; Rasmussen, Sune O.; Farmer, Elizabeth J.. |
| Building chronological frameworks for proxy sequences spanning 130-60 ka b2k is plagued by difficulties and uncertainties. Recent developments in the North Atlantic region, however, affirm the potential offered by tephrochronology and specifically the search for cryptotephra. Here we review the potential offered by tephrostratigraphy for sequences spanning 130-60 ka b2k. We combine newly identified cryptotephra deposits from the NGRIP ice-core and a marine core from the Iceland Basin with previously published data from the ice and marine realms to construct the first tephrostratigraphical framework for this time-interval. Forty-three tephra or cryptotephra deposits are incorporated into this framework; twenty three tephra deposits are found in the... |
| Tipo: Text |
Palavras-chave: Tephra; Cryptotephra; Tephrostratigraphy; Greenland ice-cores; North Atlantic marine cores; Iceland; Tephra correlations; Glass-shard analysis; Rapid climate changes. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40029/39255.pdf |
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| Blockley, Simon P. E.; Bourne, Anna J.; Brauer, Achim; Davies, Siwan M.; Hardiman, Mark; Harding, Poppy R.; Lane, Christine S.; Macleod, Alison; Matthews, Ian P.; Pyne-o'Donnell, Sean D. F.; Rasmussen, Sune O.; Wulf, Sabine; Zanchetta, Giovanni. |
| The comparison of palaeoclimate records on their own independent timescales is central to the work of the INTIMATE (INTegrating Ice core, MArine and TErrestrial records) network. For the North Atlantic region, an event stratigraphy has been established from the high-precision Greenland ice-core records and the integrated GICCO5 chronology. This stratotype provides a palaeoclimate signal to which the timing and nature of palaeoenvironmental change recorded in marine and terrestrial archives can be compared. To facilitate this wider comparison, without assuming synchroneity of climatic change/proxy response, INTIMATE has also focussed on the development of tools to achieve this. In particular the use of time-parallel marker horizons e.g. tephra layers... |
| Tipo: Text |
Palavras-chave: Event-stratigraphy; Tephrochronology; INTIMATE; Greenland ice cores; Palaeoenvironment; Palaeoclimate. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40028/39254.pdf |
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| Andersen, Katrine K.; Svensson, Anders; Johnsen, Sigfus J.; Rasmussen, Sune O.; Bigler, Matthias; Rothlisberger, Regine; Ruth, Urs; Siggaard-andersen, Marie-louise; Steffensen, Jorgen Peder; Dahl-jensen, Dorthe; Vinther, Bo M.; Clausen, Henrik B.. |
| The Greenland Ice Core Chronology 2005, GICC05, is extended back to 42 ka b2k (before 2000 AD), i.e. to the end of Greenland Stadial II. The chronology is based on independent multi-parameter counting of annual layers using comprehensive high-resolution measurements available from the North Greenland Ice Core Project, NGRIP. These are measurements of visual stratigraphy, conductivity of the solid ice, electrolytical melt water conductivity and the concentration of Na+, Ca2+, SO42-, NO3-, NH4+. An uncertainty estimate of the time scale is obtained from identification of 'uncertain' annual layers, which are counted as 0.5 +/- 0.5 years. The sum of the uncertain annual layers, the so-called maximum counting error of the presented chronology ranges from 4% in... |
| Tipo: Text |
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| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34497/33450.pdf |
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