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Roberts, N.
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- PublicationRestrictedTephrostratigraphy, chronology and climatic events of the Mediterranean basin during the Holocene: An overview(2011-02)
; ; ; ; ; ; ; ; ; ;Zanchetta, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Sulpizio, R.; University of Bari, Italy ;Roberts, N.; University of Plymouth, UK ;Cioni, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Eastwood, W. J.; University of Birmingham, UK ;Siani, G.; CNRS - Université Paris-Sud XI, France ;Caron, B.; University of Pisa, Italy and CNRS-Université Paris-Sud XI, France ;Paterne, M.; Laboratoire des Sciences du Climat et de l'Environment, France ;Santacroce, R.; University of Pisa, Italy; ; ; ; ; ; ; ; The identification and characterisation of high-frequency climatic changes during the Holocene requires natural archives with precise and accurate chronological control, which is usually difficult to achieve using only 14C chronologies. The presence of time-spaced tephra beds in Quaternary Mediterranean successions represents an additional, independent tool for dating and correlating different sedimentary archives. These tephra layers are potentially useful for resolving long-standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives. Known major tephras of regional extent derive from central and southern Italy, the Hellenic Arc, and from Anatolia. A striking feature of major Holocene tephra deposition events in the Mediterranean is that they are clustered rather than randomly distributed in time. Several tephra layers occurred at the time of the S1 sapropel formation between c. 8.4 and 9.0 ka BP (Mercato, Gabellotto-Fiumebianco/E1, Cappadocia) and other important tephra layers (Avellino, Agnano Monte Spina, ‘Khabur’ and Santorini/Thera) occurred during the second and third millennia BC, marking an important and complex phase of environmental changes during the mid- to late-Holocene climatic transition. There is great potential in using cryptotephra to overlap geographically Italian volcanic ashes with those originating from the Aegean and Anatolia, in order to connect regional tephrochronologies between the central and eastern Mediterranean.187 25 - PublicationRestrictedMultiproxy record for the last 4500 years from Lake Shkodra (Albania/Montenegro)(2012)
; ; ; ; ; ; ; ; ; ; ;Zanchetta, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Van Welden, A.; Geological Survey of Norway (NGU), Trondheim, Norway ;Baneschi, I.; IGG-CNR sez. Pisa, Pisa, Italy ;Drysdale, R. N.; Department of Resource Management and Geography, University of Melbourne, Victoria, Australia ;Sadori, L.; Dipartimento di Biologia Ambientale, Università ‘La Sapienza’, Rome, Italy ;Roberts, N.; School of Geography, Earth and Environmental Sciences, University of Plymouth, UK ;Giardini, M.; Dipartimento di Biologia Ambientale, Università ‘La Sapienza’, Rome, Italy ;Beck, C.; Laboratoire de Géodynamique des Chaînes Alpines, Université de Savoie, Le Bourget du Lac, France ;Pascucci, V.; Dipartimento Scienze Botaniche, Ecologiche e Geologiche University of Sassari, Sassari, Italy ;Sulpizio, R.; Dipartimento Scienze della Terra e Geoambientali, University of Bari, Bari, Italy; ; ; ; ; ; ; ; ; A multi-proxy record is presented for approximately the last 4500 cal a BP from Lake Shkodra, Albania/Montenegro. Lithological analyses, C/N ratio and δ13C of the organic and inorganic carbon component suggest that organic matter and bulk carbonate are predominantly authigenic. The δ18O record of bulk carbonate indicates the presence of two prominent wet periods: one at ca. 4300 cal a BP and one at ca. 2500–2000 cal a BP. The latter phase is also found in southern Spain and Central Italy, and represents a prominent event in the western and central Mediterranean. In the last 2000 years, four relatively wet intervals occurred between ca. 1800 and 1500 cal a BP (150–450 AD), 1350–1250 (600–700 AD), 1100–800 (850–1150 AD), and at ca. 90 cal a BP (1860 AD). Between ca. 4100 and 2500 cal a BP δ18O values are relatively high, with three prominent peaks indicating drier conditions at ca. 4100–4000 cal a BP, ca. 3500 and at ca. 3300 cal a BP. Four additional drier events are identified at 1850 (ca. 100 AD), 1400 (ca. 550 AD), 1150 (800 AD) and ca.750 cal a BP (1200 AD). The pollen record does not show changes in accordance with these episodes owing to the poor sensitivity of vegetation in this area, which is dominated by an orographic rainfall effect and where changes in altitudinal vegetation belts do not affect the pollen rain in the lake catchment. However, since ca. 900 cal a BP a significant decrease in the percentage arboreal pollen and in pollen concentrations suggest major deforestation produced by human activities. Copyright © 2012 John Wiley & Sons, Ltd.186 17