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| Lowe, John J.; Blockley, Simon; Trincardi, Fabio; Asioli, Alessandra; Cattaneo, Antonio; Matthews, I. P.; Pollard, M.; Wulf, S.. |
| The first part of this paper presents a review of the problems that constrain the reliability of radiocarbon-based age models with particular focus on those used to underpin marine records. The reasons why radiocarbon data-sets need to be much more comprehensive than has been the norm hitherto, and why age models should be based on calibrated data only, are outlined. The complexity of the probability structure of calibrated radiocarbon data and the advantages of a Bayesian statistical approach for constructing calibrated age models are illustrated. The second part of the paper tests the potential for reducing the uncertainties that constrain radiocarbon-based age models using tephrostratigraphy. Fine (distal) ash layers of Holocene age preserved in... |
| Tipo: Text |
Palavras-chave: Radiocarbon-based age models; Tephrochronology; Volcanic event stratigraphy; Lago Monticchio record; Bayesian method; WDS geochemical data; Discriminant function analysis (DFA). |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00039/15025/12429.pdf |
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| Manighetti, B; Palmer, A; Eden, D; Elliot, M. |
| We identify c. 7000 cal yr BP Tuhua Tephra in a marine sediment core from offshore eastern North Island, New Zealand. Its mineral assemblage includes aegirine, which is diagnostic for the Tuhua (Mayor Island) Volcanic Centre, and electron microprobe analyses of glass shards yield compositions close to published analyses of the tephra onshore, closer to the source. Associated radiocarbon ages on planktonic foraminifera from the core show that its age lies within the range previously determined for the caldera-forming event that generated Tuhua Tephra. This occurrence, >380 km southeast of the source, indicates that the dispersal of the ash was bi-directional, and that earlier estimates of this tephra's volume may be conservative. |
| Tipo: Text |
Palavras-chave: Mayor Island; Tephrochronology; Holocene; Tuhua Tephra; Isopach. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00225/33656/32097.pdf |
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| Rutledal, Sunniva; Berben, Sarah M.p.; Dokken, Trond M.; Van Der Bilt, Willem G.m.; Cederstrøm, Jan Magne; Jansen, Eystein. |
| Geochemically distinct volcanic ash (tephra) deposits are increasingly acknowledged as a key geochronological tool to synchronize independent paleoclimate archives. Recent advances in the detection of invisible (crypto) tephra have led to the ongoing establishment, development and integration of regional tephra lattices. These frameworks offer an overview of the spatial extent of geochemically characterized tephra from dated eruptions – a valuable tool for precise correlation of paleorecords within these areas. Here, we harness cryptotephra analysis to investigate the occurrence of two well-known tephra markers from the Last Glacial Period (i.e. FMAZ II-1 (26.7 ka b2k) and NAAZ II (II-RHY-1) (55.3 ka b2k)), in marine sediment cores from the Nordic,... |
| Tipo: Text |
Palavras-chave: Tephrochronology; Cryptotephra Tephrostratigraphy; Tephra isochrons; FMAZ II; NAAZ II; Geochemistry; Paleoceanography; Marine sediment cores Quaternary; North Atlantic Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00614/72659/71665.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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| Weller, D. J.; Miranda, C. G.; Moreno, P. I.; Villa-martinez, R.; Stern, C. R.. |
| Correlations among and identification of the source volcanoes for over 60 Late Glacial and Holocene tephras preserved in eight lacustrine sediment cores taken from small lakes near Coyhaique, Chile (46 degrees S), were made based on the stratigraphic position of the tephra in the cores, lithostratigraphic data (tephra layer thickness and grain size), and tephra petrochemistry (glass color and morphology, phenocryst phases, and bulk-tephra trace element contents determined by ICP-MS). The cores preserve a record of explosive eruptions, since similar to 17,800 calibrated years before present (cal years BP), of the volcanoes of the southernmost Andean Southern Volcanic Zone (SSVZ). The suggested source volcanoes for 55 of these tephras include Hudson (32... |
| Tipo: Text |
Palavras-chave: Andean volcanism; Tephra; Tephrochronology; Hudson volcano; Chile. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00497/60839/64295.pdf |
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