European Glacial Landscapes: Maximum Extent of Glaciations

European Glacial Landscapes: Maximum Extent of Glaciations brings together relevant experts on the history of glaciers and their impact on the landscape of the main regions of Europe. In some regions the largest recorded glaciations occurred before the Last Glacial Cycle, in one of the major glacial cycles of the Middle Pleistocene. However, the best-preserved evidence of glaciation in the landscape is from the Last Glacial Cycle (Late Pleistocene). The book also analyses these older glacial landforms that can sometimes still be seen in the landscape today. This analysis provides a better understanding of the succession of Pleistocene glaciations and the intervening interglacial periods, examining their possible continental synchrony or asynchrony of past glacier behaviour. The result of this analysis gives important new insights and information on the origin and effects of climatic and geomorphological variability across Europe.

European Glacial Landscapes: Maximum Extent of Glaciations examines the landscapes produced by glaciers throughout Europe, the geomorphological effects of glaciations, as well as the chronology and evolution of the past glaciers, with the aim of understanding the interrelationship between glacial expansion and climate changes on this continent. This book is a valuable tool for geographers, geologist, environmental scientists, researchers in physics and earth sciences.

• Provides a synthesis that highlights the main similarities or differences, through both space and time, during the maximum recorded expansions of Pleistocene glaciers in Europe
• Features research from experts in glacial geomorphology, palaeo-glaciology, palaeo-climatology and palaeo-oceanography on glacial expansion in Europe
• Includes detailed color figures and maps, providing a comprehensive comparison of the glacial landscapes of European Pleistocene glaciers

• Language: English
• Publisher: Elsevier Science
• Release date: Nov 19, 2021
• ISBN: 9780128236079

Book preview

Part I

Introduction

Outline

Chapter 1 Introduction

Chapter 2 The Quaternary ice ages

Chapter 3 Previous synthesis of European Glacial Landscapes

Chapter 1

Introduction

David Palacios¹, Nuria Andrés¹, Philip D. Hughes² and José M. García-Ruiz³,    ¹Department of Geography, Universidad Complutense de Madrid, Madrid, Spain,    ²Department of Geography, School of Environment, Education and Development, The University of Manchester, Manchester, United Kingdom,    ³Pyrenean Institute of Ecology (IPE-CSIC), Zaragoza, Spain

Abstract

The aim of this book is to synthesise the state of knowledge on the morphology and origin of European Glacial Landscapes in most of their regions and their climatic context. Following the Introduction section, Part II is devoted to the geological, geomorphological, and climatic description of the studied regions; Part III describes the main aspects determining climate variability during the Last Glacial Cycle; Part IV describes glacially sculpted landforms and associated sediments before the Last Glacial Maximum (LGM); and Part V describes landforms sculpted during the LGM. Throughout the book the different regions are grouped according to the presence or not of the European Ice Sheet Complex. At the end of Parts IV and V, a concluding chapter synthesises the overall characteristics of the glacial landscapes of each of these periods. Finally, Part VI attempts to correlate the description of the climate in Part III with the extent of the glacial landscapes in Parts IV and V. The ages described in the book and other parameters, as well as the maps, are standardised so that the glacial landforms of different regions and periods can be compared.

Keywords

European Glacial Landscapes book; structure; content of the book; standardised parameters used

Chapter Outline

Outline

1.1 The advance in knowledge of the glacial landscapes 3

1.2 Objectives of the book 4

1.3 The glaciated European regions 5

1.4 The climatic context during the sculpting of the European glacial landscapes 5

1.5 The age and characteristics of European glacial landscapes 6

1.6 Standardised ages and maps used in the book 7

References 8

1.1 The advance in knowledge of the glacial landscapes

Much of Europe, from Northern Scandinavia and Iceland to the Southern Iberian Peninsula, has been covered by valley glaciers and extensive ice sheets during long periods of the Pleistocene. Consequently, in both highlands and wide areas of the lowlands (particularly in Sweden, Finland, Northern Russia, and Central Europe) deposits of glacial origin (frontal moraines, different types of tills, lateral moraines, drumlins, and eskers) and other deposits indirectly related to glaciers (fluvioglacial terraces, lacustrine deposits, kames, and outwash plains) can frequently be found. Besides, many of the landforms (large polished surfaces, U-shaped valleys, overexcavated basins, fjords, and glacial lakes) contribute to producing spectacular landforms, which has favoured landscape heterogeneity and biodiversity in mountains and plains. The organisation of the current fluvial network in Central and Northwestern Europe is a consequence of the advance and subsequent setbacks of the huge ice sheet of Northern Europe. And the wide alpine valleys dominated at their head by magnificent cirques, and vertical cliffs are related to the activity of glacial tongues that had a great erosive capacity, transformed the relief, and favoured a massive sediment transfer. Glaciers have long dominated much of Europe and have left us traces of the interactions between glacial dynamics, climatic changes, lithology, and preglacial relief. The influence of glaciers is so great that they even condition the characteristics of cultivated areas, the distribution of the mountain meadows, the high productivity of the Central European plain, and even the distribution of forest species in relation to the presence of certain moraine deposits.

Current glaciers in Europe are restricted to cirques and valleys in many of its mountains, especially in the Alps (with some glacial tongues exceeding 10 km in length), but also in the Pyrenees, Carpathians, Balkans, and Urals. Relatively large glaciers are still preserved in the Arctic and sub-Arctic regions, such as in the Scandinavian mountains, Iceland, the Svalbard archipelago, and the island of Severny.

In Chapter 2, The Quaternary Ice Ages, we explain how glacial landscapes were discovered in the course of the 19th century, representing the impact of previous ice ages. Since then, the science has tried to explain when and how these ice ages occurred, what elements (landforms, distinct types of sediments) remain in the landscape from the persistent presence of glaciers, and what changes in climate, atmospheric dynamics, and ocean currents caused the extension and, later, the retreat and disappearance of the glaciers. The problem has been approached from numerous disciplines, such as geomorphology, palaeoclimatology, palaeoceanography, and palynology. In recent decades, scientific advances in each of these disciplines have contributed to provide a global perspective on landscape and environmental changes during the Pleistocene.

A critical step has been the knowledge of the ratio, in the ocean sediments of foraminifera shells, between the heavy oxygen isotope (¹⁸O), indicative of low evaporation in the sea, and the light isotope (¹⁶O), indicative of high evaporation. The different distribution of this ratio made possible to know the sequence of ices ages or glacial cycles, separated by interglacial periods, during the last 5 million years (see Chapter 21: An Overview of the Last Glacial Period). Each period with the same ratio is called Marine Isotope Stage (MIS), where even numbers indicate large amounts of ice on the Earth (high values of δ¹⁸O) and, therefore, low sea level, and odd numbers indicate small amounts of ice (low values of δ¹⁸O) and high sea level (see Chapter 22: Ice Volume and Sea-Level Changes During Last Glacial Cycle: Evidence From Marine Records and Chapter 23: Definition of the Last Glacial Cycle Marine Stages and Chronology). This climate variability has also been detected in air bubbles trapped in the deep Greenland ice cores for the last half a million years. In this case the climatic cycles, called Dansgaard–Oeschger (D–O) cycles, were also identified by the δ¹⁸O/δ¹⁶O ratio, although in the opposite sense that in the marine sediments (low ratios are indicative of cold periods) [see Chapter 24: Abrupt (or Millennial or Sub-Orbital) Climatic Variability: Dansgaard–Oeschger Events]. The study of marine sediments also revealed the existence of large discharges of icebergs, mainly from the Hudson Strait Ice Stream of the Laurentide Ice Sheet, which reached up to the latitude 43°N and deposited coarse-grained iceberg-rafted debris. These were called Heinrich events, which occurred up to six times during the Last Glacial Cycle (LGC) (see Chapter 25: Abrupt (or millennial or sub-orbital) climatic variability: Heinrich events / stadials).

During some of the glacial cycles of the last 800,00 years (especially during MIS 16, 12, 6, and 5d-2), large ice masses in the form of ice sheets (IS) spread across continental and marine regions. One of these huge IS directly affected Europe: from Scandinavia (Fennoscandia IS) and the Barents Sea IS to Northern and Central Europe and the North Sea, and from the British Isles IS to converge in what has been called the European Ice Sheet Complex (EISC) (Chapters 28: The European Ice Sheet Complex evolution prior to the Last Glacial Maximum and Chapter 47: European Ice Sheet Complex Evolution During the Last Glacial Maximum). The glaciers of each glacial cycle left their imprints on the landscape, although younger glacial cycles erased most of the landforms and sediments let by previous cycles. For this reason, most of Europe’s glacial landforms we can find in the current landscapes were sculpted during the LGC.

Scientists engaged in the study of palaeoenvironments have come a long way to determine the age of glacial landforms. Radiocarbon dating has been possible since the mid-20th century, although it faces two problems: (1) glacial sediments rarely contain organic matter, so only sediments indirectly related to glaciers (e.g., fluvial terraces and lacustrine sediments) can be dated, and (2) the limit for radiocarbon dating is only 60 ka. Optically stimulated luminescence methods constrain the time at which a mineral, normally quartz, contained in a moraine was last exposed to light, making possible to date sediments without organic matter. Other techniques occasionally used have been U-series dating to date sediments and landforms cemented by secondary carbonates and speleothems in cave systems under glaciated terrains, and also ⁴⁰Ar/³⁹Ar ages of volcanic tephras overlying deposits associated with glaciation. However, during the first two decades of the 21st century, the most relevant progress to date glacial landforms and events has been the widespread use of the method for dating the exposure of rock surfaces to cosmogenic radiation. This exposition generates specific isotopes of certain elements in the rocks, with ¹⁰Be and ³⁶Cl being the most widely used cosmogenic isotopes. This method makes it possible to directly determine the time of exposition to this radiation (age) in erosional and sedimentary glacial landforms, with a huge range of potential ages, from a few hundred to millions of years.

1.2 Objectives of the book

After two centuries of progress in the study of European Glacial Landscapes, we need to update the knowledge and have a global perspective on the great fluctuations experienced in the evolution of glaciers. Undoubtedly, the large number of available dates, the progress experienced by the different sciences involved in the study of palaeoglaciers, and the excellent information accumulated on glaciers in the different European regions advise us to reflect on what we know and how we should conduct our research in the future. For these reasons the aims of this book are (1) to synthesise the state of knowledge on the morphology and origin of European Glacial Landscapes in most of their regions; and (2) to place this glacial evolution in the context of climate changes and the temperature and flow characteristics of the oceans when the most important glacial events occurred.

It is noteworthy that although the main focus of the book is on glacial landforms, special emphasis is also placed on landforms and deposits indirectly related to glaciers (glaciofluvial terraces, glaciolacustrine sediments, etc.) or triggered during the retreat of glaciers (e.g., debris flows, avalanches, landslides, and collapses). The book also gives great importance to submarine glacial landforms and deposits, developed under the sea or, sometimes, in subaerial conditions and subsequently flooded by the sea level rise during deglaciation.

1.3 The glaciated European regions

The geographical characteristics of the different regions studied are presented in Part II of this book, as well as the importance of their glacial landscapes. In addition, these chapters explain how the glacial landscapes were discovered and their knowledge advanced. Most of the glaciated regions of Europe have been included in this book, with few exceptions. These regions have been divided into two groups. The first group includes the regions that have been affected by the EISC. After a common introduction in Chapter 4, The European Ice Sheet Complex, the following regions have been included within this group: Fennoscandia (i.e., Scandinavia, Denmark, and Finland; Chapter 5: Glacial Landscapes of Fennoscandia); Northern Central Europe (here Northern Germany, Northern Poland, Northern Belarus, and the Baltic countries; Chapter 6: Glacial Landscapes of Northern Central Europe); European Russia (here Pskov, Novgorod, Leningrad, Murmansk, Arkhangelsk, Moscow, Smolensk, Tver, Yaroslavl, and Vologda Russian Districts, as well as in the republics of Komi and Karelia; Chapter 7: Glacial Landscapes of European Russia); Eurasian Arctic (Barents Sea, Kara Sea, associated High Arctic islands and archipelagos, and the adjacent mainland of Arctic Russia; Chapter 8: Glacial Landscapes of the Eurasian Arctic); North Sea and Mid-Norwegian continental margin (Chapter 9: Glacial landscapes of the North Sea and Mid Norwegian Continental Margin); Britain and Ireland (Chapter 10: Glacial Landscapes of Britain and Ireland).

The second group includes mountainous regions not directly affected by the EISC: the Urals (Chapter 11: Glacial Landscapes of the Ural Mountains), with occasional invasions by the EISC; Iceland (Chapter 12: Glacial Landscapes of Iceland), which was covered by the Icelandic IS, although it always remained separated from the EISC; the Tatra Mountains (Chapter 13: Glacial Landscapes of the Tatra Mountains); the Romanian Carpathians (Chapter 14: Glacial Landscapes of the Romanian Carpathians); the Alps (Chapter 15: Glacial Landscapes of the Alps); the Pyrenees (Chapter 16: Glacial Landscapes of the Pyrenees); the Iberian Peninsula ranges, grouped in Chapter 17: Glacial Landscapes of the Iberian Mountains; the Italian Mountains, mainly the Apennines (Chapter 18: Glacial Landscapes of the Italian Mountains); the Balkans (Chapter 19: Glacial Landscapes of the Balkans); and the mountains of the Anatolian Peninsula (Chapter 20: Glacial Landscapes of the Anatolian Mountains), which despite technically being in Asia have also been included because of their fundamental contribution to the understanding of glaciers in Southeast Europe (Fig. 1.1).

Figure 1.1 The studied European regions. The regions affected by the EISC are highlighted in red: (1) Fennoscandia; (2) Northern Central Europe; (3) European Russia; (4) Eurasian Arctic; (5) North Sea (A) and Mid-Norwegian continental margin (B); and chapter (6); Britain and Ireland. The regions not directly affected by the EISC are highlighted in black: (7) Urals; (8) Iceland; (9) the Tatra Mountains; (10) the Romanian Carpathians; (11) the Alps; (12) the Pyrenees; (13) the Iberian Peninsula ranges; (14) the Italian Mountains; (15) the Balkans; and (16) the mountains of the Anatolian Peninsula. EISC, European Ice Sheet Complex.

1.4 The climatic context during the sculpting of the European glacial landscapes

As already indicated, the aim of this book is to describe the origin and importance of glacial landforms in Europe. We noted that the LGC partially erased the landforms sculpted in previous cycles. For this reason the book devotes Part III to describe the state of knowledge on the evolution of climate and ocean dynamics during the LGC, to explain their influence on the extent of glaciers, and to understand how glaciers influenced climate and ocean dynamics, in a constant feedback process.

Therefore Part III exposes the general characteristics of the LGC (Chapter 21: An Overview of the Last Glacial Period); the information provided by marine records on the ice volume and sea level changes and the MIS definition and chronology (Chapter 22: Ice Volume and Sea-Level Changes During Last Glacial Cycle: Evidence From Marine Records and Chapter 23: Definition of the Last Glacial Cycle Marine Stages and Chronology); the definition and chronology of the D–O cycles (Chapter 24: Abrupt (or Millennial or Sub-Orbital) Climatic Variability: Dansgaard–Oeschger Events) and of the Heinrich events (Chapter 25: Abrupt (or Millennial or Sub-Orbital) Climatic Variability: Heinrich Events); and the chronological identification of a key period called the Last Glacial Maximum (LGM) (from 29 to 19 ka in this book), when glaciers recorded their maximum extent. Its chronology is under discussion, as not all glaciers recorded their last maximum extent at the same time due to local reasons and to global atmospheric circulation. In this book, we have determined a time window for this period between 29 and 19 ka, an eclectic solution, looking for a common criterion. The climate of the LGM is discussed in Chapter 26, The Global Last Glacial Maximum: The Eastern North Atlantic (Marine Sediments) and the Greenland Ice-Sheet Climatic Signal, and the concept of the term and its possible chronology is discussed in Chapter 46, Concept and Global Context of the Glacial Landforms from the Last Glacial Maximum.

1.5 The age and characteristics of European glacial landscapes

The book deals with the study of European glacial landforms according to their different ages. As noted earlier, the LGC erased many of the earlier glacial landforms. Many of the glaciers reached their maximum extent in the LGC during the LGM and consequently the areas covered by glacial landforms prior to the LGM are not easy to detect and occupy very small areas. Besides, the LGM glacial landforms were partially erased during deglaciation, from 19 ka onward, resulting in an extremely complex landscape organisation. Considering these circumstances, in this Volume I we have grouped the pre-LGM glacial landforms in Part IV and the LGM glacial landforms in Part V. We have left for Volume II the landforms that were generated during the deglaciation (18.9–11.7 ka), until the beginning of the present interglacial, the Holocene.

Thus Part IV focuses on the study of glacial landforms developed before the LGM, and that were not covered by glaciers during the LGM. Some of these landforms are located beyond the areas directly eroded by glaciers during the LGM, and, therefore, they were not modified. Nevertheless, even in this situation the older glacial landforms have suffered degradation by periglacial weathering and by the inevitable passage of time and in many cases the evidence is the subject of subsurface glacial geology rather than geomorphology. In some other cases, landforms prior to LGM even survived burial by ice during the LGM, due to the local presence of cold-based, nonerosive ice. Besides, some sediments corresponding to old glacial cycles could have been covered and protected by sediments deposited by LGM glaciers, such that a thick succession of sediments report a variety of palaeoenvironmental events and sedimentary conditions, increasing the complexity of glacial environments.

Chapter 27, Concept and Global Context of the Glacial Landforms Prior to the Last Glacial Maximum, provides an overview of the pre-LGM ice ages and its current state of knowledge in Europe. Chapter 28, The European Ice Sheet Complex evolution prior to the Last Glacial Maximum, updates the evolution of the EISC prior to the LGM, and Chapters 29–34 explain the extent and main landforms in the different regions directly affected by the EISC. Landscapes originated by glaciers before the LGM outside the EISC are described in Chapters 35–44.

A similar distribution of chapters has been arranged in Part V for European landscapes affected by glaciers during the LGM. Thus Chapter 46, Concept and Global Context of the Glacial Landforms From the Last Glacial Maximum, introduces the concept of LGM and the environmental context in which it occurred, Chapters 47–53 analyse glacial landforms and extent of the EISC during the LGM, and Chapters 54–63 are devoted to LGM in the European mountains outside the EISC.

The book also seeks to synthesise the glacial evolution across Europe, trying to underline the regional trends and contrasts (Chapter 45: The European Glacial Landscapes Prior to the Last Glacial Maximum and Chapter 64: The European Glacial Landscapes From the Last Glacial Maximum, for the pre-LGM and the LGM, respectively). Finally, Chapter 65, The Importance of European Glacial Landscapes in a Context of Great Climatic Variability, examines the interrelationship between climate and glacial fluctuations, particularly during the LGC.

1.6 Standardised ages and maps used in the book

The variety of dating methods used to date glacial sediments and landforms has already been shown earlier. Each method has improved over the last decades so that ages calculated a few years ago may be somewhat different from those obtained today, even if the same dating method is used. This is especially so for radiocarbon and cosmogenic exposure dating. It is, therefore, necessary to update some previous age calculations so that they are comparable across regions.

The terrestrial ¹⁴C dates have been calibrated using the CALIB 7.1 or OXCAL programs. The marine AMS ¹⁴C dates younger than 21.786-kyr BP have been calibrated: (1) using the CALIB 7.10 program and the global marine calibration dataset (Marine13) (Hughen et al., 2004). To accommodate local effects, it was necessary to introduce the Delta R of the place where the core was retrieved following the suggestion of Reimer et al. (2013) (http://calib.org/marine/google/). (2) As an option, it was constructed the age model using the open-source software Clam 2.2 (Blaauw, 2010) (http://www.chrono.qub.ac.uk/blaauw/clam.html) implemented in the R environment (R Development Core Team, 2013), or using Oxcal program version 4.2 (Ramsey et al., 2010) (https://c14.arch.ox.ac.uk/oxcal.html). Both programs have a choice for using the Marine13 calibration dataset and introduce the Delta R for each study place (http://calib.org/marine/google/). (3) IntCal20 was available during the writing of this book and was also used.

Efforts were also made to unify cosmogenic exposure ages. This was mostly important for legacy exposure ages published more than around 5 years ago, because of newly established production rates and developments/improvements in the age calculators. CRONUScalc (Marrero et al., 2016a) was used on recalculations for the whole-rock cosmogenic ³⁶Cl ages on moraine boulders and glacially polished rock surfaces (http://cronus.cosmogenicnuclides.rocks/2.0/html/cl/). ¹⁰Be cosmogenic ages have been recalculated by using CRONUScalc (Marrero et al., 2016b) (http://cronus.cosmogenicnuclides.rocks/2.0/html/al-be/). The CREp (Cosmic Ray Exposure Program) online calculator (Martin et al., 2017; http://crep.crpg.cnrs-nancy.fr/#/) has also been used, as the result difference is less than 5% with the aforementioned calculators. With the aim of unifying the exposure age calculation for all samples, we have applied the Lifton–Dunai–Sato (LDS) scaling scheme (Lifton et al., 2014), the ERA40 atmospheric model (Uppala et al., 2005), and the geomagnetic database based on the LDS framework (Lifton et al., 2014). In some cases where topographic shielding has a major influence on exposure ages, the topographic shielding factor of each ¹⁰Be/³⁶Cl sampling site has been recalculated through the Topographic Shielding Factor through the Topographic Shielding Calculator v.2 belonging to the CRONUSCalc Program (Marrero et al., 2016b): http://cronus.cosmogenicnuclides.rocks/2.0/html/topo/. However, for those samples, field measurements of which for topographic shielding factor calculation are unreliable or unavailable, it has been obtained from the Point-based Shielding Model GIS-tool devised by Li (2018) (http://web.utk.edu/~yli32/pointshielding.zip), which implements the method proposed by Balco et al. (2008). Where not enough data have been provided to perform a recalculation, it has been indicated in the text and its relative value has been provided.

The maps in the book show common symbols so that they can be clearly compared between the different regions. The colour ramps for the topographic bases (altimetry and bathymetry) have been designed taking into account the great variety of continental and seabed reliefs. The maps have been elaborated from open data from the General Bathymetric Chart of the Oceans 2020 Global Grid (GEBCO Compilation Group, 2020), a global continuous terrain model for ocean and land with a spatial resolution of 15 arc seconds, or from the Danielson and Gesch (2011) (Danielson and Gesch, 2011) product, a global DEM available with 30-, 15-, and 7.5-arc-second spatial resolutions. To facilitate the location of the sites mentioned in the text, a KML file is included for each of the study regions. It can be viewed on Google Earth or in a GIS.

To be able to compare the extent of glaciers in the different periods and regions, tables have been drawn up in which, for each mountain region and period, glacier parameters that are easy to obtain and compare are indicated. For these mountain areas, in addition to the altitudes of the peaks, the minimum altitude of the glacier fronts and the value of the equilibrium lines altitude (ELA) have been indicated for each period. Most of the ELAs have been calculated by the Toe to Headwall Ratio (THAR) method, with a ratio of 0.4, except where another method is indicated in the chapter.

References

Balco et al., 2008 Balco G, Stone JO, Lifton NA, Dunai TJ. A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements. Quaternary Geochronology. 2008;3(3):174–195 https://doi.org/10.1016/j.quageo.2007.12.001.

Blaauw, 2010 Blaauw M. Methods and code for ‘classical’ age-modelling of radiocarbon sequences. Quaternary Geochronology. 2010;5(5):512–518 https://doi.org/10.1016/j.quageo.2010.01.002.

Danielson and Gesch, 2011 Danielson, J.J., & Gesch, D.B. (2011). Global multi-resolution terrain elevation data 2010 (GMTED2010) (p. 26). US Department of the Interior, US Geological Survey. Available from https://doi.org/10.5066/F7J38R2N.

GEBCO Compilation Group, 2020 GEBCO Compilation Group. 2020. GEBCO 2020 Grid. Available from https://doi.org/10.5285/a29c5465-b138-234d-e053-6c86abc040b9.

Hughen et al., 2004 Hughen KA, Baillie MG, Bard E, et al. Marine04 marine radiocarbon age calibration, 0–26 cal kyr BP. Radiocarbon. 2004;46(3):1059–1086.

Li, 2018 Li YK. Determining topographic shielding from digital elevation models for cosmogenic nuclide analysis: a GIS model for discrete sample sites. Journal of Mountain Science. 2018;15(5):939–947 https://doi.org/10.1007/s11629-018-4895-4.

Lifton et al., 2014 Lifton N, Sato T, Dunai TJ. Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes. Earth and Planetary Science Letters. 2014;386:149–160 https://doi.org/10.1016/j.epsl.2013.10.052.

Marrero et al., 2016a Marrero SM, Phillips FM, Caffee MW, Gosse JC. CRONUS-Earth cosmogenic 36Cl calibration. Quaternary Geochronology. 2016a;31:199–219 https://doi.org/10.1016/j.quageo.2015.10.002.

Marrero et al., 2016b Marrero SM, Phillips FM, Borchers B, Lifton N, Aumer R, Balco G. Cosmogenic nuclide systematics and the CRONUScalc program. Quaternary Geochronology. 2016b;31:160–187 https://doi.org/10.1016/j.quageo.2015.09.005.

Martin et al., 2017 Martin LCP, Blard PH, Balco G, et al. The CREp program and the ICE-D production rate calibration database: a fully parameterizable and updated online tool to compute cosmic-ray exposure ages. Quaternary Geochronology. 2017;38:25–49 https://doi.org/10.1016/j.quageo.2016.11.006.

R Development Core Team, 2013 R Development Core Team. R: A Language and Environment for Statistical Computing Vienna: R Foundation for Statistical Computing; 2013; ISBN 3–900051-07–0 http://www.r-project.org.

Ramsey et al., 2010 Ramsey CB, Dee M, Lee S, Nakagawa T, Staff RA. Developments in the calibration and modeling of radiocarbon dates. Radiocarbon. 2010;52(3):953–961 https://doi.org/10.1017/S0033822200046063.

Reimer et al., 2013 Reimer PJ, Bard E, Bayliss A, et al. IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon. 2013;55(4):1869–1887 https://doi.org/10.2458/azu_js_rc.55.16947.

Uppala et al., 2005 Uppala SM, Kållberg PW, Simmons AJ, et al. The ERA-40 re-analysis. Quarterly Journal of the Royal Meteorological Society: A Journal of the Atmospheric Sciences, Applied Meteorology and Physical Oceanography. 2005;131(612):2961–3012 https://doi.org/10.1256/qj.04.176.

Chapter 2

The Quaternary ice ages

David Palacios¹, Philip D. Hughes², José M. García-Ruiz³ and Nuria Andrés¹,    ¹Department of Geography, Universidad Complutense de Madrid, Madrid, Spain,    ²Department of Geography, School of Environment, Education and Development, The University of Manchester, Manchester, United Kingdom,    ³Pyrenean Institute of Ecology (IPE-CSIC), Zaragoza, Spain

Abstract

At the end of the 18th century, advances in natural sciences led to the discovery of fossil cold-adapted animal species that had become extinct a few thousand years ago and the existence of glacial landforms and sediments in European regions located far from mountain areas where glaciers still existed. The early 19th century saw the development of theories about the existence of ice ages during the Quaternary period, coinciding with the appearance of humans. By the end of the 19th century, the extent of glacial landscapes in Europe had been recognised. Throughout the first half of the 20th century, the main glacial landforms were delimited both in mountain ranges and in Central and Northern Europe. Since the middle of the 20th century, a progressively more accurate chronology of numerous glacial cycles has been established with the application of radiocarbon dating and the oxygen isotope analysis of foraminifera in marine sediments. Furthermore, the existence of such cycles has been related to changes in the Earth’s orbit, climatic and oceanic effects of which in the Northern Hemisphere caused the growth of ice sheets, in several pulses with an average duration of ~100 ka over the last 10 glacial cycles. When ice sheets reached a critical maximum, a complex series of reverse processes in the atmosphere and the oceans led to the rapid disappearance of the northern continental ice sheets in about 10 ka. At the end of each glaciation, warmer interglacial periods of about 15–10 ka have occurred, and have been followed by a gradual descent into a new period of glaciation.

Keywords

Ice ages; glacial cycles; Glacial Termination; Quaternary; interglacial

Chapter Outline

Outline

2.1 The discovery of the Quaternary ice ages 9

2.2 The antecedents of the Quaternary ice ages 10

2.3 Causes and characteristics of the Quaternary ice ages 12

References 16

Glaciers make up some of the most impressive landscapes on the Earth. For this reason, they have attracted the interest of visitors, artists, adventurers, and scientists. In the case of scientists, they have been interested in (1) the landforms derived from the action of glaciers, (2) the sediments deposited by glacial erosion and transport, (3) the physical dynamics of ice in a heterogeneous relief, (4) the existence of fluctuations in the extent occupied by glaciers, (5) the age of forms and sediments, and (6) the influence of glaciers and extremely cold climates on the river morphology and the current and past distribution of living organisms, among other issues. The discovery of a succession of cyclical ice ages represented a milestone for the study of the Quaternary palaeoenvironments and for explaining the different landforms related to morphoclimatic processes. This chapter makes a brief presentation of the steps that have significantly improved the knowledge about the ice ages, the existence of very old glaciations, and the causes of the great climatic cycles that explain the expansion and contraction of large ice masses.

2.1 The discovery of the Quaternary ice ages

At the end of the 18th century, when the natural sciences began to take off, two great discoveries were the main trigger for knowledge about the ice ages (Woodward, 2014; Ehlers et al., 2018). Palaeontologists found frozen mammoths and many other extinct mammals in Siberia, adapted to live under very cold climates. In addition, early glacial gemorpho-logists discovered that polished surfaces, erratic blocks, and moraines, similar to those that glaciers were then developing at their fronts, were found in the Alps, North Europe, Scandinavia, and the British Isles. They were surprised because such glacial landforms and deposits were located at long distances from the present glacial fronts or even in areas where no glaciers existed. The main conclusion was that there must have been much more extensive glaciers in such regions in the past so that the presence of these glacial landscapes could be explained (Venetz, 1821; Esmark, 1824; de Charpentier, 1841). Subsequently, the past melting of these large ice masses was linked to changes in sea level, especially in the littoral of the Scandinavian Peninsula and the British Isles (Lyell, 1835; Jamieson, 1865). Palaeontologist Cuvier (1815) formulated his catastrophist theory of the disappearance of mammoths and much of Europe’s fauna as a consequence of a major climate crisis. Hutton (1795) proposed that the current glacial relief was the result of a long process of changes, wherein many landforms were inherited from the past. A disciple of Cuvier, but based on the Huttonian uniformitarian theory, Agassiz (1840) disseminated the theory about the existence of global ice ages in the last millions of years. Throughout the second half of the 19th century, the Agassiz theory was accepted and numerous glacial landforms and major frontal moraines were described, which helped to delimit the maximum expansion of the large continental ice masses (known as ice sheets) over Europe and North America, with impressive precision (Geikie, 1894; Wright, 1889).

The current knowledge on European glacial landscapes has been achieved by overcoming four major steps, once the theory of the Ice Ages had been accepted and demonstrated and their spatial impact in Europe had been delimited:

1. The occurrence of four Ice Ages based on observations of glacial and fluvioglacial landforms in the Alps at the beginning of the 20th century. These ice ages were initially called Gunz, Mindel, Riss, and Würm (ordered from the oldest to the newest) in relation to terraces and piedmonts in rivers of the Alps, where they had been first observed (Penck and Brückner, 1901–1909). These ages were limited to the Quaternary, the last geological age determined by the existence of humans.

2. Identification, description, and delimitation of different generations of glacial landforms in the north of the continent and in most European mountains.

3. The increasing use, in the second half of the 20th century, of radiocarbon dating, particularly in sediments marginal to glacial landforms (e.g., glaciolacustrine deposits), and the publication of the first proposals for absolute glacial chronology. The geomorphological advances were, at least in part, supported by progresses in the climatology of the Quaternary, based on ¹⁸O isotopic studies in ice and marine sediment cores (see chapters 20: An overview of the last glacial period, and 21: Ice volume and sea-level changes during Last Glacial Cycle: evidence from marine records).

4. The application of new methods of dating applied directly to glacial landforms, such as optically stimulated luminescence (OSL) and cosmogenic isotope methods (see Chapter 1: Introduction). This fourth step, which is currently in full development, has been a key factor in the emergence of a new terrestrial glacial chronology, correlated with the chronology provided by palaeoclimatologists. This should be the basis for tackling the fifth step in the knowledge of European glacial landscapes: to understand why and how the climate changes in such a way that glaciers grow over long cold periods leading to ice ages, and which are the causes of sudden climate changes that result in the rapid melting of ice masses (Fig. 2.1). The influence of human activities on glacier fluctuations will also be a critical question for scientists and policy makers.

Figure 2.1 Number of times that the ice sheets have covered the European continent over the last 950 ka. The map is based on the ice sheet extents (best estimates) from MIS 2, 4, 6, 8, 10, 12, 16, and 20–24. Ice sheet boundaries during MIS 6 and LGM are highlighted. LGM, Last Glacial Maximum; MIS, marine isotope stages; NH, Northern Hemisphere; SH, Southern Hemisphere. Performed with data adapted from Batchelor, C.L., Margold, M., Krapp, M., Murton, D.K., Dalton, A.S., Gibbard, P.L., et al., 2019. The configuration of Northern Hemisphere ice sheets through the Quaternary. Nature Communications 10, 1–10. https://doi.org/10.1038/s41467-019-11601-2 (Batchelor et al., 2019).

2.2 The antecedents of the Quaternary ice ages

The Quaternary is one of the five major glacial periods in the history of our planet (Imbrie and Imbrie, 1986). The first recorded ice age occurred between 2.4 and 2.1 billion years ago, called the Huronian, because of the many outcrops of glacial sediments that emerge around Lake Huron. The second great ice age was 720–630 million years ago and was so intense that it affected the entire planet, including the equatorial zone (Snowball Earth Theory). The third one occurred between 460 and 420 million years ago and clear remnants remain in the Sahara and the Andes. The penultimate great ice age was between 360 and 260 million years ago, at the end of the Palaeozoic Era. Since then, a warm climate prevailed on the Earth, without the existence of glaciers, until 45 million years ago, when a general cooling began and the first glaciers appeared on the planet after 215 million years.

The Earth’s climate experienced its last extreme warm period ~56 million years ago, during what has been called the Palaeocene–Eocene Thermal Maximum (between 8°C and 12°C above the current average temperature of the Earth), in the complete absence of ice, even seasonal sea ice (Stokke et al., 2020) (Fig. 2.2). Since then, the climate gradually cooled, with cold and dry cycles alternating with shorter, warmer, and wetter periods. The continents gradually acquired positions close to the current ones, and in Antarctica, already located at the South Pole, began the expansion of glaciers 44.5 million years ago, whereas it developed a permanent ice sheet similar in size to the current one 35 million years ago (Ingólfsson, 2004; Barker et al., 2007). At the same time, glaciers started to be present at Greenland (Bierman et al., 2014). About 23 million years ago there was a sharp rise in temperature, followed by a period of warm stability, which led to the melting of West Antarctica, while the East Antarctic Ice Sheet survived (Gasson et al., 2016). Since 14 million years ago, an abrupt cooling of 6°C–7°C allowed the reconstruction of the entire Antarctic Ice Sheet, which has continued until now (Shevenell et al., 2004), and the Greenland Ice Sheet expanded to reach an area similar than today (Bierman et al., 2014). Since then there has been a constant cooling trend, in a general pattern of cold and dry periods alternating with warm and wet ones, and with increasingly extreme temperatures. This global cooling trend coincided with the closure of the Isthmus of Panama (Montes et al., 2015), more than 15–13 million years ago, 10 million years earlier than previously thought (cf. Burton et al., 1997). The closure of the Central American Seaway led to the formation of the Atlantic Meridional Overturning Circulation (AMOC) transporting warm and salty waters from the Caribbean to the North Atlantic and sinking carbon and nutrients into the deep ocean toward the South Atlantic, a key ocean circulation pattern for the evolution of future ice ages (Kirillova et al., 2019). Before 3 million years, there was a new warm period, lasting approximately 300 ka long, with temperatures 2°C–3°C higher than today in mid- and high latitudes, and sea level 25 m higher than today as a consequence of the lack of glaciers in the Northern Hemisphere (Goldner et al., 2014).

Figure 2.2 Evolution of the mean temperature in relation compared to present during the last 55 million years according to the δ¹⁸O record in marine sediments. The chronology of the main geological events determining the evolution of the Earth’s temperature is provided. Data from Zachos, J.C., Dickens, G.R., Zeebe, R.E., 2008. An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451 (7176), 279–283. https://doi.org/10.1038/nature06588 (Zachos et al., 2008) and adapted from Westerhold, T., Marwan, N., Drury, A.J., Liebrand, D., Agnini, C., Anagnostou, E., et al. (2020). An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science 369 (6509), 1383–1387. https://doi.org/10.1126/science.aba6853 (Westerhold et al., 2020).

2.3 Causes and characteristics of the Quaternary ice ages

The Quaternary begins 2.58 ka ago and is divided into Pleistocene (2.58–11.7 ka) and Holocene (11.7 ka to present) (Gibbard and Cohen, 2008). The most peculiar feature of the Quaternary ice ages was that great ice sheets spread se-veral or seve-ral times over the north of North America and Eurasia (Figs. 2.1 and 2.3). The information accumulated in marine sediments (ratio of δ¹⁸O in the foraminifera shells) has allowed us the identification of 41 cold periods, of which 14 left evidence that glaciers reached the oceans, although many more glaciations were confined to the interior of the continents (Ehlers et al., 2018).

Figure 2.3 Evolution of the δ¹⁸O record in marine sediments, showing the evolution of the Earth’s temperature and the proportion of water in glaciers over the last 5.5 million years. Note the increase in the length and severity of the cycles and their thermal amplitude over the last 800 ka. Data from Lisiecki, L.E., Raymo, M.E., 2005. A Pliocene-Pleistocene stack of 57 globally distributed benthic δ¹⁸O records. Paleoceanography 20 (1). https://doi.org/10.1029/2004PA001071 (Lisiecki and Raymo, 2005).

At the beginning of the 20th century, the main interest of cryosphere sciences focused on finding the causes leading to the succession of the Quaternary glacial and interglacial cycles. Following on from earlier ideas in the 19th century of Joseph Adhémar and James Croll [see review by Imbrie (1982)], Milankovitch (1941) showed how such cycles could be due to changes in summer solar radiation at mid-latitudes caused by cyclical variations in the Earth’s orbital movements (orbital effect). Milankovitch’s theory resurfaced with force when Hays et al. (1976) discovered that the temperature evolution of the Earth, obtained from δ¹⁸O in the marine sediment cores, directly reflected the frequencies of the three orbital movements: precession, with a cycle each 21 ka, obliquity with a cycle each 40 ka, and eccentricity with a cycle each 100 ka. Subsequent studies confirmed this close relationship between orbital cycles and glaciations so that Milankovitch’s theory and the contribution of Hays, Imbrie, and Shackleton remain the key to interpreting the cyclical sequence of glaciations (Maslin, 2016). However, the climate system is extremely complex and reacts, although not li-nearly, to the orbital effect (Tziperman et al., 2006; Hodell, 2016). The unresolved issue is that the Quaternary glacial cycles have not had the same duration. Early Quaternary glacial cycles lasted 41 ka, probably controlled by obliquity. In the last 1 Ma, especially since the mid-Pleistocene transition ~800 ka ago, glacial cycles have averaged 100 ka (between 80 and 120 ka in the last 10 cycles) and, at the same time, the temperature amplitude of such cycles have become more extreme (Hughes and Gibbard, 2018). However, the pattern of glacier development in each glacial cycle has not been uniform with significant differences in ice extent recorded on land between glacial cycles (see Hughes et al., 2020). While 100 ka has become the dominant approximate frequency for glacial cycles, the complexity of glacier response to global climate change in glacial cycles cannot be explained by orbital eccentricity alone. Eccentricity (cycles of 100 ka) does not have a large effect on overall global solar radiation receipt. However, precession and obli-quity do have major effects on the distribution of solar receipt across the Earth, especially between the hemispheres, and influence seasonality. It is, therefore, under debate whether each of the glacial cycles were the consequence of four or five precessional cycles (Hays et al., 1976; Cheng et al., 2016) or of two or three obliquity cycles (Huybers and Wunsch, 2005; Maslin and Brierley, 2015), or a combination of these two orbital movements (Imbrie and Imbrie, 1986; Tziperman et al., 2006; Huybers, 2011).

The reason why orbital cycles influence the genesis of ice ages in the Quaternary may be explained by the distribution of the planet’s relief and the configuration of the continents in the prelude to the Quaternary. The arrangement of large continental masses in the Northern Hemisphere; the isolation of the Antarctic continent by the opening of the Drake Passage and the formation of Antarctic Circumpolar Current; the alpine orogeny and the uplift of the great mountain ranges, like the Alps, Himalaya, Andes,… and plateaus, like the Andean Altiplano or the Tibetan Plateau, often perpendicular to the general atmospheric circulation; the great volcanic variability that accompanied this orogeny and, in particular, the closing of the Isthmus of Panama and the formation of the AMOC, have meant that small changes in the seasonal and latitudinal distribution of insolation resulting from orbital movements have great consequences on the planet’s climate (Lisiecki, 2014; Ehlers et al., 2018; van de Lagemaat et al., 2021; Starr et al., 2021).

The difference in solar radiation that the orbital movements produce in the mid-latitudes is a major cause of glaciations, just enhanced by the existence of huge continental masses in such mid-latitudes of the Northern Hemisphere (Denton et al., 2010). Indeed, the continents themselves amplify the orbital effect during glaciations. Snow that remains on continents for long periods drastically reduces albedo and contributes to lower temperatures, sea ice expands, evaporation is reduced, and vegetation cover decreases, thus reducing albedo even further. Besides, the expansion of ice on the northern continents reinforces the polar anticyclones in this hemisphere, and the polar air masses force the polar front and the Intertropical Convergence Zone to migrate south, weakening or even cancelling the Asian monsoon (Novello et al., 2017). The intensity of the large marine circulation that exchanges heat and salinity throughout the Atlantic, the AMOC, drastically declines, causing the storage of large masses of carbon dioxide (CO2) in the Southern Ocean, thus reducing its greenhouse effect on the atmosphere (Böhm et al., 2015) and, therefore, lowering the temperature on the Earth. As the continental ice masses increase, sea level decreases, evaporation is drastically reduced, the amount of dust in the atmosphere increases, further reducing the effects of solar radiation. All these feedback processes reinforce the growth of the large ice sheets in the northern continents, which advance in very unstable pulses. These include a succession of large cold (stadials) and short warm (interstadials) periods. Each stadial usually increases the area of the ice sheets more than in previous ones (Fig. 2.4).

Figure 2.4 Evolution of parameters indicating the climate evolution over the last 800 ka. (A) Stable isotope (δDeuterium) record from the EDC ice core showing the Quaternary temperature variations in Antarctica ( Jouzel et al., 2007). (B) Composite CO2 record (0–800 ka BP) for Antarctica ( Lüthi et al., 2008). (C) Dust record from the EDC ice core covering 0–800 ka BP. Measurements of dust concentration percentage using both laser and Coulter counter methods ( Lambert et al., 2008). (D) Global sea level stack ( Spratt and Lisiecki, 2016). MIS are given in italic Arabic numerals. EDC, EPICA Dome C; EPICA, European Project for Ice Coring in Antarctica; MIS, Marine isotope stages.

The growth process of the ice sheets in the northern continent is not unlimited. There is a sharp limit in terms of the ratio of frozen water stored and ice sheets’ spatial expansion. This limit is called the Maximum Critical Growth of the Northern Hemisphere Ice Sheets (Birchfield and Broecker, 1990; Imbrie et al., 1993; Raymo, 1997; Paillard, 1998; Denton et al., 2010; Abe-Ouchi et al., 2013; Deaney et al., 2017). This maximum growth causes the expansion of the ice sheets until reaching their maximum extent on the continents, which one glaciation after another tends to be very similar, with few exceptions. The Maximum Critical Growth of the ice sheets represented the maximum isostatic depression over the continents and, therefore, a large part of the ice sheets became marine-based at their maximum (Gildor et al., 2014), coinciding with minimum CO2 in the atmosphere (Shakun et al., 2012), and leading to minimum precipitation and plant cover density. Under such circumstances the amount of dust in the atmosphere was so high that it reduced the Earth’s albedo drastically and could be the main triggering factor for deglaciation (Ellis and Palmer, 2016). An increase in solar radiation during summer to 65°N due to orbital factors would quickly melt the area occupied by the large marine-based ice sheets which would collapse due to the subsequent rise in the sea level (Brook and Buizert, 2018).

The collapse of the northern continental ice sheets causes a sudden chain reaction, contrary to the processes that facilitated their growth: reduction in albedo and in the amount of atmospheric dust, rising sea levels, increased precipitation, and expansion of vegetation cover. The Asian monsoon recovers, the AMOC strengthens, and Intertropical Convergence Zone returns to the equator, all of which cause CO2 stored in the southern oceans to be released and increase dramatically in the atmosphere (Broecker, 1998; Denton et al., 2010; Deaney et al., 2017). The deglaciation process, which has been called Glacial Terminations, occurs quickly and culminates in the disappearance of the northern continent ice sheets in a few thousand years (Fig. 2.5). The sea level, which had fallen pulse by pulse over the 100 ka until it reached a minimum at the end of the glaciation, rises sharply in about 10 ka during Terminations, cycle after cycle, to stabilise in the interglacial for another 10–15 ka, until the onset of the new glaciation.

Figure 2.5 Sea level evolution over the last 250 ka. Note the parallels between the glacial cycles, with a slow growth of the Northern Ice Sheets, in particular the Laurentide Ice Sheet, as well as much of the European Ice Sheet Complex, vast size of which dominates the marine isotopic record (Hughes and Gibbard, 2018, 2020), until the onset of an abrupt melt (Termination) that ends each cycle. Data from Spratt, R.M., Lisiecki, L.E., 2016. A Late Pleistocene sea level stack. Climate of the Past 12 (4), 1079–1092. https://doi.org/10.5194/cp-12-1079-2016.

The time needed for Northern Ice Sheets to record their Maximum Critical Growth has been increasing throughout the Pleistocene (Clark et al., 2006), and successively more solar radiation was required to start Terminations. As a consequence, each glacial cycle tends to last longer than its predecessor (Tzedakis et al., 2017). The greatest extensions and durations of the Quaternary glaciations took place in the second half of the Pleistocene. Major glaciations occurred during MIS 16 (676–621 ka), MIS 12 (478–424 ka), MIS 6 (191–130 ka), and MIS 5d–2 (115–14 ka) and were interspersed with smaller glaciations, such as MIS 14 (563–524 ka), MIS 10 (374–337 ka), and MIS 8 (300–243 ka) (Hughes et al., 2020). The last two glaciations during MIS 6 and MIS 5d–2 were some of the most extreme glaciations in the Quaternary (Hughes and Gibbard, 2018). The extensive glaciers that formed in these last two glacial cycles means that the evidence of the earlier less severe glaciations (such as in MIS 10 and 8) has been eroded away, and consequently are often missing from terrestrial glacial records (Hughes et al., 2020).

European landscapes reflect only the glacier expansion of the LGCs. Strictly speaking, the concept of a glacial cycle refers to the period from the end of the previous Termination to the end of the next one and includes Interglacials (Hughes and Gibbard, 2018). However, in this book we use the term glacial cycle as analogous to the period of global glacier expansion and the major Pleistocene cold stages (i.e., MIS 6 and 5d-2). The LGC ran from the end of the Last Interglacial (Eemian) to the beginning of the present one (Holocene), from 115 to 11.7 ka. The culmination of each glacial cycle coincides with the lowest sea level, just before the start of Terminations. The most recent of these culminations is called the Last Glacial Maximum that occurred in the interval 29–19 ka. However, not all the European glacier fronts reached their maximum Quaternary expansion in this period. Some glaciers reached their maximum extents earlier in the LGC or in previous glacial cycles, particularly during MIS 6, and occasionally during MIS 12 and MIS 16. This book will analyse the glacial landforms sculpted in these cycles by the ice masses (ranging in size from from ice sheets to cirque glaciers) in the different European regions.

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Chapter 3

Previous synthesis of European Glacial Landscapes

José M. García-Ruiz,    Pyrenean Institute of Ecology (IPE-CSIC), Zaragoza, Spain

Abstract

Studies on glaciers in Europe have been developed in three phases: (1) a pioneer phase, with the descriptive observation of glacial landforms and the incipient identification of different glaciations; (2) a mapping phase, with the distribution of glacial landforms and sediments on geomorphological maps; and (3) the use of a variety of methods to date moraines and associated deposits, such as glacial terraces and glaciolacustrine deposits. A series of books, review papers, and monographic issues have contributed to provide a global perspective on the evolution of glaciers and the processes that explain the resulting landforms since at least the Middle Pleistocene until the Last Glacial Maximum.

Keywords

European glacial landscapes; last glacial maximum; pioneering glacial studies; glacial synthesis

Chapter Outline

Outline

References 22

Landscapes in Europe retain the imprints of the long-term presence of glaciers in mountains and plains, where many of the landforms and deposits are the direct and indirect result of glacial erosion at different temporal and spatial scales. Few people are aware of the areas covered by ice masses when glaciers were at their maximum extent during the Global Last Glacial Maximum (in general, 26–19-ka BP, LGM) or in previous glacial cycles. For instance, the European Ice Sheet Complex (EISC), mainly centred on the Scandinavian Peninsula and Northern Finland, was so large that it covered the Netherlands, Denmark, and the northern plains of Germany, Poland, Belarus, and Russia and occasionally made contact with the ice sheet of the British Isles, where the ice almost reached London during the most extensive glaciation. This conditioned the relief characteristics, the opportunity for soils to develop, and the structure of drainage networks so that the layout of many major European rivers aligns with the position of moraines and ice during the Pleistocene glaciations. This was the case with the rivers Elbe, Thames, and Rhine, where the latter flowed toward the Rhone until changing its course