DATE2018-05-19 11:53:53
IDABSTRACT20180519115353-0184
CONTACTmstyllas@gmail.com
PRESENTATIONORAL
INVITED0
IDSESSION2
TITLETHE LATEGLACIAL AND HOLOCENE GLACIAL HISTORY OF THE NORTHEAST MEDITERRANEAN MOUNTAINS INFERRED FROM IN-SITU PRODUCED COSMIC RAY EXPOSURE DATINGS OF PALEO-GLACIERS DEPOSITS. IMPLICATIONS FOR THE RELATIVE ROLES OF EXTERNAL AND INTERNAL CLIMATE FORCING.
AUTHORSMN Styllas (1), I Schimmelpfennig (2), L Benedetti (2), M Ghilardi (2), G Aumaître (2,3), D Bourles (2,3), K Keddadouche (2,3)
AFFILIATIONS
  1. GEOSERVICE LTD, Athens, Greece
  2. Aix Marseille Univ, CNRS, IRD, INRA, CoF, CEREGE, Aix-en-Provence, France
  3. ASTER Team, Aix-en-Provence, France
ABSTRACTA new glacial chronology from Mount Olympus in Greece, based on 20 36Cl in situ produced cosmic ray exposure (CRE) datings is used to complement existing CRE chronologies from the northeast Mediterranean (NEM) region. The new 36Cl ages of the glacial landforms range from 15.6 ± 2.0 to 0.6 ± 0.08 ka, spanning the Lateglacial and the Holocene. Based on the Probability Density Functions of all existing CRE ages, the Lateglacial is partitioned in three distinct phases (LG1-3): an initial phase of glacial moraine stabilization at 15.06 ± 0.53 ka with subsequent deglaciation starting at ~14 ka (LG1) evident in Mount Pelister, Sâra Range, Galicica Mountains, Mount Olympus, Rila Mountains and Mount Uludag. LG1 was followed by a transition to conditions marginal for glaciation at 13.3 ± 1.21 ka (LG2), recorded only on Mount Olympus that was characterized by enhanced aeolian activity (westerlies) and large amounts of windblown snow. Glacial conditions characterized by low temperatures and low precipitation, returned to the NEM mountains at 11.9 ± 0.56 ka (LG3), but they were not widespread as they are found on Sâra Range, Mount Uludag, Mount Chelmos and Mount Olympus. NEM glacial phases LG1-3 occurred during a period of increasing obliquity and peak eccentricity and exhibit an out-of-phase behaviour with the local solar insolation record from Duhlata Cave. Phases LG1 and LG3 occurred during solar insolation maxima and also coincided with a shutdown of the Atlantic Meridional Overturning Circulation (AMOC), whereas LG2 occurred during insolation minima with concurrent establishment of the AMOC. The Holocene glacial phases (HOL1-3) are recorded only in Mount Olympus. An early Holocene glacier stillstand (HOL1) at 9.6 ± 1.1 ka, occurred during peak obliquity, increasing solar insolation close to the record’s peak values and is locally associated with a lagged recovery of north Aegean Sea Surface Temperatures (SST’s). No glacier activity is observed during the mid-Holocene (~9.0 – 3.0 ka). The Late Holocene glacier expansions, include a moraine stabilization phase (HOL2) at 2.5 ± 0.3 ka, a period that coincides with solar insolation minima (Homeric Low), combined with a negative North Atlantic Oscillation (NAO) phase, which resulted in locally wet conditions, as recorded in Skala Marion Cave speleothem record. The last phase of glacial activity (HOL3) corresponds to the early part of the Little Ice Age (0.6 ± 0.08 ka). A link between the Holocene glaciations with the north Atlantic climatic regime is evident, as HOL1, 2 and 3 glacial phases, broadly correspond to Bond 6, 2 and 0 events. The new Lateglacial and Holocene glacial chronology emphasizes the relative controls of internal and external forcing along the headwaters of the major Northeast Mediterranean fluvial systems, is in pace with numerous regional and local terrestrial and marine proxies and establishes the basis for a source-to-sink approach to paleoenvironmental reconstrunctions.
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