Abrupt climate changes of the last deglaciation detected in a Western Mediterranean forest record

Type Article
Date 2010
Language English
Author(s) Fletcher W. J.1, 2, Goni M. F. Sanchez1, Peyron O.3, Dormoy I.3
Affiliation(s) 1 : Univ Bordeaux 1, Ecole Prat Hautes Etud, CNRS, EPOC,UMR 5805, F-33405 Talence, France.
2 : Goethe Univ Frankfurt, Inst Geosci, D-60438 Frankfurt, Germany.
3 : Univ Franche Comte, CNRS, UMR 6249, Lab Chronoenvironm, F-25030 Besancon, France.
Source Climate Of The Past (1814-9324) (Copernicus Gesellschaft Mbh), 2010 , Vol. 6 , N. 2 , P. 245-264
DOI 10.5194/cpd-5-203-2009
WOS© Times Cited 125
Abstract Abrupt changes in Western Mediterranean climate during the last deglaciation (20 to 6 cal ka BP) are detected in marine core MD95-2043 (Alboran Sea) through the investigation of high-resolution pollen data and pollen-based climate reconstructions by the modern analogue technique (MAT) for annual precipitation (P-ann) and mean temperatures of the coldest and warmest months (MTCO and MTWA). Changes in temperate Mediterranean forest development and composition and MAT reconstructions indicate major climatic shifts with parallel temperature and precipitation changes at the onsets of Heinrich stadial 1 (equivalent to the Oldest Dryas), the Bolling-Allerod (BA), and the Younger Dryas (YD). Multi-centennial-scale oscillations in forest development occurred throughout the BA, YD, and early Holocene. Shifts in vegetation composition and (P-ann reconstructions indicate that forest declines occurred during dry, and generally cool, episodes centred at 14.0, 13.3, 12.9, 11.8, 10.7, 10.1, 9.2, 8.3 and 7.4 cal ka BP. The forest record also suggests multiple, low-amplitude Preboreal (PB) climate oscillations, and a marked increase in moisture availability for forest development at the end of the PB at 10.6 cal ka BP. Dry atmospheric conditions in the Western Mediterranean occurred in phase with Lateglacial events of high-latitude cooling including GI-1d (Older Dryas), GI-1b (Intra-Allerod Cold Period) and GS-1 (YD), and during Holocene events associated with high-latitude cooling, meltwater pulses and N. Atlantic ice-rafting. A possible climatic mechanism for the recurrence of dry intervals and an opposed regional precipitation pattern with respect to Western-central Europe relates to the dynamics of the westerlies and the prevalence of atmospheric blocking highs. Comparison of radiocarbon and ice-core ages for well-defined climatic transitions in the forest record suggests possible enhancement of marine reservoir ages in the Alboran Sea by 200 years (surface water age 600 years) during the Lateglacial.
Full Text
File Pages Size Access
Publisher's official version 20 1 MB Open access
Top of the page