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| Abbott, P. M.; Austin, W. E. N.; Davies, S. M.; Pearce, N. J. G.; Rasmussen, T. L.; Wastegard, S.; Brendryen, J.. |
| Previous studies of marine sequences from the Faroe Islands region have identified a series of coarse-grained tephra horizons deposited during Marine Isotope Stage (MIS) 5. Here we reassess the MIS 5 tephrostratigraphy of the Faroe Islands region and focus on the cryptotephra deposits preserved within the fine-grained fraction of marine core LINK 16. We also extend the record to encompass the late MIS 6 and early MIS 4 periods. A density separation technique, commonly used for tephra investigations in lacustrine settings but rarely applied to marine sediments, is utilised to explore the fine-grained material and EPMA and LA-ICP-MS are employed to determine the major and trace element composition of individual tephra shards. In total, 3 basaltic and 3... |
| Tipo: Text |
Palavras-chave: Volcanic ash; Iceland; Marine sequences; Isochrons; Palaeoclimatic synchronisation. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40096/38832.pdf |
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| Evans, E. E.; Davies, S. M.; Johnston, R. E.. |
| We present a series of soft sediment geological phantoms constructed to simulate volcanic ash deposits preserved within sediment cores. This study aimed to systematically discern which sediment components are most effectively detected and therefore characterised by X-ray microCT (μCT). Samples with low or overlapping attenuation contrast but distinct morphologies such as coarse grained (>125 μm) ash within fine mud (<4 μm) can be manually separated using analysis software, while samples with high attenuation contrast display distinct horizons that are easily segmented using attenuation thresholds. We anticipate that this work will have broader applications within Earth Science to optimise the exploration of sediment with μCT analysis. |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00389/50003/50588.pdf |
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| Svensson, A.; Andersen, K. K.; Bigler, M.; Clausen, H. B.; Dahl-jensen, D.; Davies, S. M.; Johnsen, S. J.; Muscheler, R.; Parrenin, F.; Rasmussen, S. O.; Roethlisberger, R.; Seierstad, I.; Steffensen, J. P.; Vinther, B. M.. |
| The Greenland Ice Core Chronology 2005 (GICC05) is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 ka extension of the time scale such that GICC05 continuously covers the past 60 ka. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12) at 46.9 +/- 1.0 ka b2k (before year AD 2000), the North Atlantic Ash Zone II layer in GI-15 at 55.4 +/- 1.2 ka b2k, and the onset of GI-17 at 59.4 +/- 1.3 ka b2k. The error estimates are derived from the accumulated number of uncertain annual... |
| Tipo: Text |
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| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00238/34893/33135.pdf |
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