Philip D. Hughes

The glacial history of the Pindus Mountains, Greece

Geomorphological evidence for Pleistocene glaciation has been mapped in the Pindus Mountains of northwest Greece, and the chronology of glaciation in this area has been established through soil profile analysis and U‐series dating of secondary carbonates (calcite) formed within glacial deposits. Three glacial stages are evident in the sedimentological and geomorphological records. The earliest and most extensive recorded glaciation predates 350,000 yr B.P. and was characterized by extensive valley glaciers and ice fields. A more recent glaciation occurred before the last interglacial and was characterized by glaciers that reached midvalley positions. The last phase of glaciation in Greece is recorded by small cirque glacier moraines and relict periglacial rock glaciers. The glacial and periglacial sequence on Mount Tymphi has been used in conjunction with a reference parastratotype, the long lacustrine sequence at Ioannina, to provide a chronostratigraphical framework for cold‐stage deposits in Greece. The three glacial stages are formally defined: the Skamnellian Stage, equivalent to the Elsterian Stage of northern Europe and marine isotope stage (MIS) 12; the Vlasian Stage, equivalent to the late Saalian Stage of northern Europe and MIS 6; and the Tymphian Stage, which is equivalent to the Weichselian/Würmian stages of northern Europe and the Alps, respectively, and MIS 5d‐2. This is the first formalized chronostratigraphical framework based on the glacial record to be established for cold stages in the Mediterranean and provides a new platform for paleoclimatological investigations in the region.

Response of a montenegro glacier to extreme summer heatwaves in 2003 and 2007

Abstract. The Debeli Namet glacier in the Durmitor massif, Montenegro, is one of the lowest altitude glaciers (2050–2300 m) at this latitude (42–44°N) in the northern hemisphere. The glacier survives well below the climatological equilibrium line altitude because of substantial inputs from avalanching and windblown snow. The glacier survived two of the hottest summers on record in 2003 and 2007, although it experienced significant retreat. However, during the intervening years (2004–2006) the glacier increased in size and advanced, forming a new frontal moraine. This rapid advance was primarily in response to much cooler summer temperatures, close to or cooler than average, and a marked increase in winter precipitation. The rapid growth and decay of the Debeli Namet glacier in response to inter‐annual climate variability highlights the sensitivity of small cirque glaciers to short‐term climate change.

Twenty-first Century Glaciers and Climate in the Prokletije Mountains, Albania

Abstract At least four active glaciers are present in the Prokletije Mountains of northern Albania. These glaciers exist at altitudes between 1980 and 2420 m a.s.l.—well below the regional equilibrium line altitude—on shaded northeast-facing slopes prone to avalanche. Glacier-climate modeling suggests that these glaciers require annual accumulation of between 4137 and 5531 mm (water equivalent) to balance melting. A significant proportion of this accumulation is likely to be sourced from windblown snow and, in particular, avalanching snow. It is estimated that the total accumulation needed to balance melting is potentially up to twice the value received from direct precipitation. The presence of these glaciers—some of the southernmost in Europe—at altitudes well below the regional equilibrium line altitude, highlights the importance of local controls on glacier development.

A GIS tool for automatic calculation of glacier equilibrium-line altitudes

A toolbox for the automated calculation of glacier equilibrium-line altitudes (ELAs) using the Accumulation Area Ratio, Area-Altitude Balance Ratio, Area-Altitude and Kurowski methods is presented. These are the most commonly-used methods of ELA calculation in palaeo-glacier reconstructions. The toolbox has been coded in Python and runs in ArcGIS requiring only the reconstructed surface of the palaeo-glacier (a DEM) as input. Through fast and automatic calculation this toolbox simplifies the process of ELA determination and can successfully work both for a single glacier and for large datasets of multiple glaciers. We describe Equilibrium Line Altitude calculation methods for palaeoglaciers.We examine suitability of each method for different glacier types.We present a toolbox for automatic ELA calculation on AAR and AABR methods.Toolbox is coded in Python and runs in ArcGIS.Toolbox use and operation are described.

Quaternary glaciation in the Atlas Mountains of North Africa

Glacial and periglacial features, formed during the Quaternary, are present throughout the Atlas Mountains in Morocco and Algeria. Moraines, U-shaped troughs, roche moutonee, riegels and cirques all provide evidence of former glacier occupation in these mountains. At least three discrete glaciations have been identified, the most recent of which occurred during the Soltanian. During the most extensive recorded phase of Pleistocene glaciation, snowlines were lowered to c. 3300 m a.s.l. in the High Atlas. Snowlines were progressively lower from the southwest of the range to the northeast with snowlines of c. 2400–2500 m a.s.l in the Middle Atlas and c. 1900–2100 m a.s.l in the Algerian Tell. This difference can probably be attributed to a precipitation gradient from north to south, with greatest levels over the Mediterranean coastal mountains of the Algerian Tell.

GlaRe, a GIS tool to reconstruct the 3D surface of palaeoglaciers

Glacier reconstructions are widely used in palaeoclimatic studies and this paper presents a new semi-automated method for generating glacier reconstructions: GlaRe, is a toolbox coded in Python and operating in ArcGIS. This toolbox provides tools to generate the ice thickness from the bed topography along a palaeoglacier flowline applying the standard flow law for ice, and generates the 3D surface of the palaeoglacier using multiple interpolation methods. The toolbox performance has been evaluated using two extant glaciers, an icefield and a cirque/valley glacier from which the subglacial topography is known, using the basic reconstruction routine in GlaRe. Results in terms of ice surface, ice extent and equilibrium line altitude show excellent agreement that confirms the robustness of this procedure in the reconstruction of palaeoglaciers from glacial landforms such as frontal moraines. GlaRe is a tool for palaeoglacier 3D surface reconstruction from bed topography.GlaRe is coded in Python and runs in ArcGIS as a toolbox.The theory of perfect plasticity equilibrium glacier profile is considered.Interpolation methods for glacier 3D surface creation are described and discussed.GlaRe is tested with two extant glaciers, showing a small, acceptable error.

Quaternary glaciation in the Mediterranean mountains: a new synthesis

Abstract The Mediterranean mountains were repeatedly glaciated during the Pleistocene. Glaciers were present in most of the major mountains areas from Morocco in the west to the Black Sea coast of Turkey in the east. Some mountains supported extensive ice caps and ice fields with valley glaciers tens of kilometres long. Other massifs sustained only small-scale ice masses, although this was the exception rather than the norm. Glaciers still exist today and there is evidence that small glaciers were a common sight in many regions during the Little Ice Age. The Mediterranean mountains are important for palaeoclimate research because of their position in the mid-latitudes and sensitivity to changes in the climate regimes of adjacent areas including the North Atlantic. These mountains are also important areas of biodiversity and long-term biological change through the Quaternary ice age. All of this provided challenges and opportunities for Palaeolithic societies. This paper reviews the history of the study of glaciation in the Mediterranean mountains from pioneer nineteenth century observations through to the detailed geomorphological mapping and advanced geochronological datasets of recent times. We also review the current state of knowledge to frame the contributions presented in this volume. Lastly, this new synthesis then identifies outstanding research problems and assesses the prospects for new studies of glaciation in the Mediterranean mountains.

Catastrophic rock avalanches in a glaciated valley of the High Atlas, Morocco: 10Be exposure ages reveal a 4.5 ka seismic event

Surface modification processes leading to large debris accumulations in high-relief mountain areas are important for understanding landscape evolution, especially in some of Earth’s most active orogens. The Arroumd rock avalanche at the foot of the NW face of Mount Aksoual (3912 m above sea level [masl]) in the Jebel Toubkal area of the High Atlas, Morocco, represents one of the largest mass movement landforms in North Africa. The age and origin of this extensive feature have been contested for over a century. Late Pleistocene moraines are also present in the same valley, adjacent to the avalanche debris. The mean of six 10 Be cosmogenic exposure ages shows that a series of catastrophic rock slope failures occurred at 4.5 ± 0.5 ka, while a set of eight exposure ages from two of the three mapped moraines has a far larger spread from 1.5 to 7.5 ka. This suggests that the avalanche events were effective agents in modifying the true surface exposure age of the Pleistocene moraines in the Arroumd valley. This has resulted in similar mean 10 Be apparent exposure ages for the preexisting Late Pleistocene moraine surfaces and Holocene catastrophic rock slope failures. Similar rock avalanche deposits are present in other glaciated valleys in the High Atlas. We conclude that the trigger for collapse was seismic activity related to proximity of the major Tizi n’Test fault. These findings have important implications for interpreting and dating glacial landforms in tectonically active settings.

Middle Pleistocene glacier behaviour in the Mediterranean: sedimentological evidence from the Pindus Mountains, Greece

Detailed sedimentological analyses of diamicton sequences in two areas of the Pindus Mountains, Greece, indicate multiple episodes of glacier advance and retreat during cold stages of the Middle-Pleistocene. These glacial sequences represent some of the most southerly in Europe and are important archives of regional and global climate change. The Pindus glaciers were relatively small by world standards and would have been highly responsive to changes in air temperature and precipitation. On Mount Tymphi, at least three phases of glacier advance are recorded within deposits assigned to the Skamnellian Stage (MIS 12). Further north on Mount Smolikas, a thick multiple diamicton sequence records evidence for multiple glacier advances during both the Skamnellian Stage and the Vlasian Stage (MIS 6). These records highlight the dynamic nature of glacier behaviour in the Mediterranean mountains during the Middle Pleistocene and provide new evidence for unstable cold stage climates.

Glacial history of Mt Chelmos, Peloponnesus, Greece

Abstract Mt Chelmos in the Peloponnesus was glaciated by a plateau ice field during the most extensive Pleistocene glaciation. Valley glaciers radiated out from an ice field over the central plateau of the massif. The largest glaciations are likely to be Middle Pleistocene in age. Smaller valley and cirque glaciers formed later and boulders on the moraines of these glacial phases have been dated using 36Cl terrestrial cosmogenic nuclide exposure dating. These ages indicate a Late Pleistocene age with glacier advance/stabilization at 40–30 ka, glacier retreat at 23–21 ka and advance/stabilization at 13–10 ka. This indicates that the glacial maximum of the last cold stage occurred during Marine Isotope Stage 3, several thousand years before the global Last Glacial Maximum (Marine Isotope Stage 2). The last phase of moraine-building occurred at the end of the Pleistocene, possibly during the Younger Dryas.