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At the Last Glacial Maximum (LGM), Britain and Ireland were covered by the British–Irish Ice Sheet (BIIS): a dynamic ice mass that comprised the southwestern extremity of the much larger European Ice Sheet Complex. However, our understanding of the extent of the BIIS has changed dramatically in recent years from a previously established view of a more restricted ice sheet, located mostly on the present-day landmass, and with significant ice-free enclaves, to an extensive marine-terminating ice sheet. Deciphering the extent and chronology of the BIIS is critical for understanding landscape evolution. It is now clear that the LGM was just one phase of an evolving ice-sheet complex, with evidence for asynchronous maximum extents across the ice-sheet sectors. Based on the lateral extents of the BIIS, the ice mass must have been sufficiently thick to completely submerge the highest terrain in the interior of the ice sheet. The widespread presence of trimlines and strongly weathered mountain summits is now mostly interpreted as evidence of nonerosive cold-based ice, rather than as LGM ice thickness markers in the landscape. Deciphering landscape history using geomorphology alone (in the absence of geochronology) is therefore complicated and can be problematic. Our understanding on the evolution of the ice sheet through time has been dramatically improved in recent years by comprehensive geochronological programmes involving BRITICE-CHRONO and other teams.

GW gratefully acknowledges the financial support provided by The University of Chester. Exploring the mode and tempo of millennial-scale climate variability under evolving boundary conditions can provide insights into tipping points in different parts of the Earth system, and can facilitate a more detailed understanding of climate teleconnections and phase relationships between different Earth system components. Here we use fossil diatom and stable carbon and oxygen isotope analysis of lake sediment deposits (core I-284) from the Ioannina basin, NW Greece, to explore in further detail millennial-scale climate instability in southern Europe during Marine Isotope Stage 6 (MIS 6; ca. 185‒130 ka). This interval correlates with the Vlasian Stage in Greece and the Late Saalian Substage in northern Europe, which were both characterised by extensive glaciations. The new dataset resolves at least 18 discrete warmer/wetter intervals, many of which were associated with strong Asian Monsoon events and North Atlantic interstadials. A number of cooler/drier intervals are also identified in the I-284 record, which are typically associated with weaker Asian Monsoon events and North Atlantic stadials, consistent with a variable Atlantic Meridional Overturning Circulation. Unlike the subdued changes in tree populations that are observed at Ioannina during mid-to-late MIS 6, the diatom record contains frequent high-amplitude oscillations in species assemblages, pointing to its sensitivity at a time when the lake system must have been close to environmental thresholds. Millennial-scale variability in diatom species assemblages continues into late MIS 6 at Ioannina, contributing important evidence for an emerging picture of frequent and persistent climate instability even at times of high global ice volume. Publisher PDF

Since the recognition in the mid-19th century that glaciers had been considerably more extensive than at present, the Quaternary (Pleistocene and Holocene series) has been synonymous with glaciation of the mid-latitudes. Today evidence from both the land and ocean-floor sediment sequences demonstrates that the major continental glaciations occurred repeatedly over what are now temperate regions of the Earth’s surface. The climatic variation that characterizes the Earth’s climate during the late Cenozoic, and indeed before, is controlled by variations of the Earth’s orbit around the Sun that therefore controlled the receipt of solar energy at the Earth’s surface. These Milankovitch variations, named after the Serbian mathematician, their discoverer, are responsible for the cyclic climate changes that characterize the Quaternary and indeed much of Earth’s history. One of the most critical ways in which the Milankovitch climate cyclicity is expressed is through the development of ‘Ice Ages’ or periods when glaciation extended across large areas of the Earth.

Ice is a major geomorphological agent. Glacial and periglacial processes have been responsible for shaping large areas of the Earth′s surface during the Quaternary – especially during Pleistocene cold stages – and are still important today at high latitudes and in mountain regions from the tropics to the poles. Glacial and periglacial landforms and sediments are important for understanding climate histories and have long been an integral part of Quaternary and Pleistocene records. In particular, recent advances in dating techniques have revitalized glacial geomorphology, and its role in reconstructing past environments is as prominent as ever. This chapter summarizes the current state of glacial knowledge around the world and selects some of the key highlights and debates.

The Atlas Mountains display evidence of extensive Pleistocene glaciations. The largest ice fields and valley glaciers formed in the Toubkal massif where multiple glacial advances are recorded. A limited number of preliminary 10 Be analyses from the oldest moraines have yielded exposure ages as old as 76 ka, intermediate moraines have yielded an age of 24 ka, whilst the youngest Pleistocene moraines correlate the Younger Dryas (12.9–11.7 ka).

The mountains of Greece contain evidence for multiple phases of ice build-up and decay during the Middle and Late Pleistocene. On Mount Tymphi, the record has been dated by applying uranium-series methods to secondary carbonates in tills. The most extensive glaciation occurred before 350 ka and is correlated with MIS 12 (Skamnellian Stage). Successively, smaller glaciations occurred during MIS 6 (Vlasian Stage), and the last glacial cycle (MIS 5d-2) or Tymphian Stage. These glaciations had major impacts on sediment and water fluxes to the fluvial system downstream. Slackwater sediments in the Voidomatis River basin record the rapid shift in river system behaviour during the last-glacial-to-interglacial transition.

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.