36Cl exposure-age chronology of Late Pleistocene glaciations on Mount Tymphi, Pindus Mountains, northwest Greece
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Date
2019-07-27
Journal Title
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Publisher
International Union for Quaternary Research (INQUA)
Abstract
The mountains of Greece and the wider Balkans were glaciated during the Pleistocene. The most extensive glaciations occurred during the Middle Pleistocene when large ice caps and glaciers formed in several ranges including the Dinaric Alps and the Pindus Mountains. The Late Pleistocene in the Balkans, however, was characterised by smaller ice masses with glaciers restricted to the highest mountains. Nevertheless, these glaciers were important in shaping much of the high mountain landscapes that we see today and they supplied many rivers with outwash sediments. Here we present preliminary results from 36Cl terrestrial cosmogenic nuclide analyses. From samples collected in summer 2017, we have calculated exposure ages from moraine boulders and glaciated bedrock in the uppermost valleys and cirques of Mount Tymphi massif (2497 m) in northwest Greece. We address both a significant geographical gap in Mediterranean glacial chronologies and the temporal gap in the glacial history of this region by targeting the previously undated Late Pleistocene glacial record. Coupled with published U-series ages from lower elevation moraines, this is the first glacial chronology in the east-central Mediterranean based on multiple dating methods.
On the southwest side of the massif, 18 exposure ages obtained from 3 moraines in the cirque and mouth of the Laccos Megalon Litharion valley and the mouth of the western cirque of Tsioumako (2155 m), indicate moraine formation between 1700 m and 2050 m a.s.l. during the Late Pleistocene. This complements previous U-series ages obtained from secondary calcites in glacial sediments below 1700 m (and elsewhere in the Balkans), which demonstrate more extensive glaciations dating to the Middle Pleistocene. At ~1430 m a.s.l. in the Laccos cirque on the northeast side of the massif, 6 exposure ages (5 boulders, 1 bedrock) from a pair of end moraines represent the first dates from this side of Mount Tymphi. They suggest small cirque glaciers persisted until at least the end of the Late Pleistocene, facilitated by avalanching snow and shading from the cliffs of Goura (2467 m). Understanding where, when and why glaciers reached their maxima during the last glacial cycle is not only important for understanding the dynamics of the glacial climate in this region, but also for the timing of sediment and meltwater delivery to river systems; the dynamics of Mediterranean refugia; and has implications for understanding the environmental context of nearby Middle and Upper Palaeolithic archaeological records.
Description
Keywords
Quaternary period, Pleistocene epoch, Age estimation, Geomorphology, Moraines, Glaciers, Greece, Mountains, Alps, Snow
Citation
Allard, J., Hughes, P., Woodward, J., Fink, D., Simon, K., & Wilcken, K. (2019). 36Cl exposure-age chronology of Late Pleistocene glaciations on Mount Tymphi, Pindus Mountains, northwest Greece. Paper presented to the 20th INQUA Congress 25th - 31st July 2019, Dublin, Ireland. Retrieved from: https://virtual.oxfordabstracts.com/#/event/public/574/submission/2205