EuroSpeleo 2016

Paleoclimate reconstruction based on stalagmite studies from Lebanon

Oral|Mr Fadi Nader

Abstract

Since 2005, studies on speleothems have been undertaken in Lebanon, for the first time, aiming at reconstructing the paleoclimate in this special location on the Levant climate belt. The studies lead to nearly continuous curves from the last Glacial period to the Middle Ages and of the Last Interglacial period and the following glacial inception.

The general pattern of the Last Interglacial (LIG) suggests wet conditions at around 130 ka with a rather active vegetation. The δ18O increase between 125.4 ka and 122.0 ka seems to be mostly due to a ‘source’ effect, suggesting a link between Mediterranean cooling and enhanced aridity. Lower growth rates and slightly higher δ13C may reflect drier conditions related to a regional climatic deterioration. During the glacial inception, two wet periods are defined based on changing growth rates and δ18O values at 108.8 ka to 99.9 ± 0.7 ka.

A stalagmite was also retrieved from and Qadisha cave (about 1750 m above sea-level, in northern Lebanon). Initial dating revealed the age of the sample between 6482±32a and 3247±127a (before 1950). Samples having similar ages from different altitudes, yet relatively close locations from central and northern Lebanon are believed to reveal invaluable information on the paleoclimate in the Levant region and on the altitude influence. Hence, new data from Lebanon completes the picture of the Levant and provides a better regional understanding of climatic changes and associated societal evolutions.