Pleistocene glaciation in the Mediterranean: extent, timing and climatic significance

  • James Allard

Student thesis: Phd

Abstract

The Mediterranean mountains were glaciated during cold stages of the Pleistocene. This glacial record is often well preserved, providing an important archive of past temperature and moisture conditions that extends deep into the Middle Pleistocene. The most extensive glaciations occurred during the Middle Pleistocene, when large ice caps developed in the upland karsts of the Balkans. It is now clear that glaciers were present throughout the Late Pleistocene across the Mediterranean. Some small glaciers remain today, sustained by favourable topoclimatic factors, although many have declined in recent decades due to rising global temperatures. This thesis presents an up-to-date meta-analysis of the geochronological record for the Mediterranean, which highlights greater complexity in the timing of Pleistocene glaciation across the region than hitherto recognised. Key aspects of the glacial record lie outside the moraines in downstream river systems and in marine settings. Despite a wealth of dates for the Late Pleistocene, the timing of glacier maxima and deglaciation in the Balkans is poorly understood. New geomorphological mapping, 52 36Cl terrestrial cosmogenic nuclide exposure ages, and palaeoglacier modelling address a geographical gap in the Mediterranean record and a temporal gap in the previously undated Late Pleistocene and Holocene records at two sites in Greece and Montenegro. Late Pleistocene glaciers were restricted to the upper valleys and cirques at Mount Tymphi in the Pindus Mountains of northwest Greece and in the Durmitor Massif, in the Dinaric Alps of northern Montenegro. The timing of moraine formation and glacier retreat at Mount Tymphi is consistent with the Voidomatis River record downstream and the Ioannina basin pollen record. Glaciers were present in the high cirques of the Durmitor Massif during the Younger Dryas. In contrast, evidence of Younger Dryas glaciation is absent from Mount Tymphi. At Durmitor, Late Holocene moraines that pre-date the Little Ice Age have been identified for the first time in the Dinaric Alps and correspond with the Late Antique Little Ice Age at c. 600 CE. This research also examines the Late Pleistocene terrestrial cosmogenic nuclide (TCN) record for the wider Mediterranean region and demonstrates that mountain glaciers responded to repeated temperature and precipitation changes in the North Atlantic during the Late Pleistocene. While 36Cl dating has enhanced our understanding of the Late Pleistocene and Holocene record, challenges still remain that inhibit our geochronological and palaeoclimatic interpretations. A key conclusion from this research is that it is preferable to use multiple radiometric and relative dating methods in limestone glaciokarst settings.
Date of Award1 Aug 2022
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorJamie Woodward (Supervisor) & Philip Hughes (Supervisor)

Keywords

  • Greece
  • Pindus Mountains
  • Moraine
  • Montenegro
  • Durmitor
  • Cosmogenic surface exposure dating
  • Geomorphology
  • Geochronology
  • Pleistocene
  • Glaciation
  • Quaternary
  • Holocene
  • Mediterranean

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