Glaciations on Ophiolite Terrain in the North Pindus Mountains, Greece: New Geomorphological Insights and Preliminary 36cl Exposure Dating

Abstract

In this paper we provide a glacial geomorphological analysis of three valleys on Mt Mavrovouni, North Pindus Mountains, Greece alongside a pilot study using cosmogenic 36 Cl to date ophiolite surfaces of glacial boulders.  At least three distinct glacial phases have been identified. Special focus is given to a sequence of younger glacial/periglacial sediments within a well-developed cirque near the highest peak of the mountain. The presented preliminary chronology of moraines and pronival ramparts is based on the new 36 Cl ages and is supported by local and regional morphostratigraphic correlations. The stabilisation of the most extensive Late Pleistocene glaciers took place at 26.6 ± 6.6 ka whereas the presence of pronival ramparts at 20.0 ± 5.0 ka suggests cold and arid conditions persisting after the Last Glacial Maximum. Older, still undated glacial deposits exist lower in the valleys which can be attributed to the Middle Pleistocene major glaciation phases (MIS 12 / MIS 6), based on their relative morphostratigraphic position within the glacial sedimentary sequence. The ages presented here are consistent with the 36 Cl-based chronologies of limestone-derived moraines on Mt Tymphi and Mt Chelmos providing an independent test to the inherent calculation uncertainties related to the estimation of erosion correction factors in carbonate lithologies. In turn, this validates the suitability of 36 Cl dating for ophiolites which has not been yet fully characterised. Overall, this study fills a geographical, methodological and temporal gap much needed to provide an improved understanding of Late Pleistocene climate oscillations and glacier dynamics in Greece and beyond.

Keywords: glacial geomorphology, Greece, ophiolites, cosmogenic 36Cl exposure age dating