Geoconservation

The detailed descriptions of the physical geography in the previous chapters show the rich geodiversity of north-western Europe, reflected in its many geological landscapes (landscapes without the biological and cultural ‘furnishing’). The various geological forces, acting in time and space have created the foundation for this richness. The landscape’s framework has mainly been designed by such endogenic processes as tectonics, orogenesis, and volcanism, while its details have been sculptured by such exogenic processes as weathering, gravity, and glacial-, fluvial-, aeolian-, and marine activities. These modelling processes resulted in a very diverse geology, geomorphology, and pedology. The long scientific tradition and the rich geodiversity made north-western Europe one of the classical areas for geological research. It therefore includes many of the international case studies in earth sciences and became the cradle of numerous international reference localities such as Emsian (Rheinland-Pfalz, Germany), Dinantian (Ardennes, Belgium), Aptian (Provence, France), Danian—Dane is Latin for Denmark (Stevens Klint), Tiglian (Middle Limburg, The Netherlands), Eemian (river in western Netherlands), etc. The chronological division of glacial and fluvioglacial features is primarily based on type localities (villages, rivers, etc.) in Denmark, northern and southern Germany, and The Netherlands. Moreover, a multitude of Tertiary and Pre-Tertiary stages of the standard geological timetable have been named after type localities of geological and prehistoric sites in France. Geological landscapes such as the Maare system of the Eifel, the volcanoes on the Massif Central (France), the Saalian and Weichselian ice-pushed ridges of Germany, The Netherlands, and Denmark as well as the impressive dunes along the coast from France to the northernmost tip of Denmark have been subjects of detailed research. These geological landscapes form a unique geological patchwork. The activities of humans, especially in the last century, have damaged or destroyed many of these landscapes and sites of geological interest. However, selected sites and areas representing the geogenesis of the earth should be preserved for the benefit of science, education, and human welfare. In all European countries attention is given to landscape preservation; however, policy and practice have mainly been based on specific biological, historical-cultural, and visual landscape qualities.

French and Belgian Uplands

The French Uplands were built by the Hercynian orogenesis. The French Massif Central occupies one-sixth of the area of France and shows various landscapes. It is the highest upland, 1,886 m at the Sancy, and the most complex. The Vosges massif is a small massif, quite similar to the Schwarzwald in Germany, from which it is separated by the Rhine Rift Valley. Near the border of France, Belgium, and Germany, the Ardennes upland has a very moderate elevation. The largest part of this massif lies in Belgium. Though Brittany is partly made up of igneous and metamorphic rocks, it cannot be truly considered as an upland; in the main parts of Brittany, altitudes are lower than in the Parisian basin. Similarities of the landscape in the French and Belgian Uplands derive from two major events: the Oligocene rifting event and the Alpine tectonic phase. The Vosges and the Massif Central are located on the collision zone of the Variscan orogen. In contrast, the Ardennes is in a marginal position where primary sediments cover the igneous basement. Four main periods are defined during the Hercynian orogenesis (Bard et al. 1980; Autran 1984; Ledru et al. 1989; Faure et al. 1997). The early Variscan period corresponds to a subduction of oceanic and continental crust and a highpressure metamorphism (450–400 Ma) The medio- Variscan period corresponds to a continent–continent collision of the chain (400–340 Ma). Metamorphism under middle pressure conditions took place and controlled the formation of many granite plutons: e.g. red granites (granites rouges), porphyroid granite, and granodiorite incorporated in a metamorphic complex basement of various rocks. The neo-Variscan period (340–320 Ma) is characterized by a strong folding event: transcurrent shear zones affected the units of the previous periods and the first sedimentary basins appeared. At the end of this period, late-Variscan (330–280 Ma), autochthonous granites crystallized under low-pressure conditions related to a post-collision thinning of the crust. Velay and Montagne Noire granites are the main massifs generated by this event. Sediment deposition in tectonic basins during Carboniferous and Permian times occurred in the Massif Central and the Vosges: facies are sandstone (Vosges), shale, coal, and sandstone in several Stephanian basins of the Massif Central, with red shale and clay ‘Rougier’ in the south-western part of the Massif Central.

Peatlands, Past and Present

Peatlands are fascinating wetland ecosystems. They provide a habitat for a wide range of highly adapted plant and animal species. In addition to the floristic and ornithological richness, peatlands have been recognized for many other values. For instance, drained peatland soils often have good agricultural properties, and peat has been and still is in some places extensively used as fuel. In coastal wetlands peat has even been used for salt extraction. Furthermore, peat is an interesting material for science, as it contains information on the palaeoecological environment, climate change, carbon history, and archaeology. In north-western Europe, peatlands were once quite extensive, covering tens of thousands of square kilometres. However, most of them have been strongly exploited by humans during past centuries. Many peatlands have been cultivated for agriculture and forestry, or have been exploited by commercial or domestic peat extraction for fuel. As a result, only a very small part of north-western Europe’s peatlands remains today in a more or less natural state. This chapter focuses on the peat deposits and peatlands in north-western Europe that have formed since the Late Glacial (c.13 ka BP). First, the most common concepts in peatland terminology are explained, and the distribution of peatlands is described. Next, processes of peat formation and the relationship between peatforming processes and climate, hydrology, vegetation, and other factors are discussed. In the following section, frequently used classification methods are presented. A historical overview of the cultivation and exploitation of peatlands is given and the present land use and characteristics of peatland soils are discussed. The following section deals with methods of conservation and rehabilitation of the remaining mires. The importance of peatlands as palaeoecological archives is examplified. Finally, the role of peatlands as a source and/or sink of CO2 and the relations with climate change are briefly explained. Peat is the unconsolidated material that predominantly consists of slightly decomposed or undecomposed organic material in which the original cellular and tissue structures can often be identified. Peat forms in lakes and mires under waterlogged, anaerobic conditions.

Aeolian Environments

The literature on aeolian processes and on aeolian morphological and sedimentological features has shown a dramatic increase during the last decade. A variety of textbooks, extensive reviews, and special issues of journal volumes devoted to aeolian research have been published (Nordstrom et al. 1990; Pye and Tsoar 1990; Kozarski 1991; Pye 1993; Pye and Lancaster 1993; Cooke et al. 1993; Lancaster 1995; Tchakerian 1995; Livingstone and Warren 1996; Goudie et al. 1999). However, not surprisingly the majority of these studies discuss aeolian processes and phenomena in the extensive warm arid regions of the world. The results of aeolian research in the less extensive, but still impressive, cold arid environments of the world are only available in a diversity of articles. At best they are only briefly mentioned in textbooks on aeolian geomorphology (Koster 1988, 1995; McKenna-Neuman 1993). Likewise, the literature with respect to wind-driven deposits in western Europe is scattered and not easily accessible. The aeolian geological record for Europe, as reflected in the ‘European sand belt’ in the north-western and central European Lowlands, which extends from Britain to the Polish–Russian border, is known in great detail (Koster 1988; van Geel et al. 1989; Böse 1991). Zeeberg (1998) showed that extensive aeolian deposits progress with two separate arms into the Baltic Region, and into Belorussia and northernmost Ukraine. Recently, Mangerud et al. (1999) concluded that the sand belt extends even to the Pechora lowlands close to the north-western border of the Ural mountain range in Russia. Sand dunes and cover sands are widespread and well developed in this easternmost extension of the European sand belt. The northerly edges of this sand belt more or less coincide with the maximal position of the Late Weichselian (Devensian, Vistulian) ice sheet, while the southern edges grade into coverloams or sandy loess and loess (Mücher 1986; Siebertz 1988; Antoine et al. 1999). However, along these southern edges the dune fields and sand sheets regionally are derived from different sources, such as the sands of the Keuper Formation or the floodplains of the Rhine and Main rivers.

Quaternary Climatic Changes and Landscape Evolution

The last 2–3 Ma have witnessed climatic changes of a scale unknown to the preceding 300 Ma. In the cold periods vegetation was reduced to a steppe, giving rise to large-scale aeolian deposition of sand and loess and river sands and gravels. In the warm stages, flora and fauna recolonized the region. Parts of Europe were repeatedly covered by mountain glaciers or continental ice sheets which brought along huge amounts of unweathered rock debris from their source areas. The ice sheets dammed rivers and redirected drainage towards the North Sea. They created a new, glacial landscape. This chapter presents an outline of the climatic history, and in particular the glacial processes involved in shaping the landscapes of western Europe. By convention, geologists generally tend to draw stratigraphical boundaries in marine deposits because they are more likely to represent continuous sedimentation and relatively consistent environments in comparison to terrestrial sediments. However, marine deposits from the period in question are relatively rarely exposed at the surface. According to a conclusion of the International Geological Congress 1948 the Tertiary/Quaternary boundary was defined as the base of the marine deposits of the Calabrian in southern Italy. In the Calabrian sediments fossils are found that reflect a very distinct climatic cooling (amongst others the foraminifer Hyalinea baltica). This climatic change roughly coincides with a reversal of the earth’s magnetic field; it is situated at the upper boundary of what is called the Olduvai Event. Consequently, it is relatively easy to identify; its age is today estimated at 1.77 Ma (Shackleton et al. 1990). However, in contrast to the older parts of the earth’s history, the significant changes within the Quaternary are not changes in faunal composition but changes in climate. For reasons of long-term climatic evolution the base of the Calabrian is not a very suitable global boundary. Its adoption excludes some of the major glaciations from the Quaternary. Therefore, in major parts of Europe another Tertiary/Quaternary boundary is in use, based on the stratigraphy of the Lower Rhine area (e.g. Zagwijn 1989). Here the most significant climatic change is already recorded as far back as the Gauss/Matuyama magnetic reversal (some 2.6 Ma ago).

Geomorphic Hazards and Natural Risks

Western European countries are subject to natural phenomena that can cause disasters. Their origins are various: geophysical (earthquakes), hydrometeorological (sea storms, floods, and avalanches), or geomorphologic (landslides). They are fairly widespread but less frequent and of relatively low intensity compared with other regions of the world; for example, an earthquake in France or Belgium is not likely to be as violent as in Greece or Japan. Some of the countries concerned, such as France and Germany, are subject to all the hazards mentioned above, while Denmark and The Netherlands are seldom exposed to earthquakes and never to avalanches because they have no mountains. Man is not responsible for phenomena such as earthquakes, but contributes significantly to the onset and aggravation of other hazards, and is sometimes largely responsible for the direct and indirect consequences, having built and maintained installations in ‘risk’ sectors. The number of victims and the cost of the damage may be high, depending on the circumstances, the intensity, and the duration of the phenomenon. Western European countries have experienced real natural disasters in the distant or recent past. Floods following a storm wave in The Netherlands in 1953 were responsible for some 2,000 deaths and damage amounting to over 3 billion Euros. Two hundred people died in the most destructive flood ever known in France in 1930 in the Tarn (Ledoux 1995). Natural phenomena such as these can recur with at least the same intensity but may entail much greater damage because of increased human occupation in the sectors concerned: the flooding submerges zones which are much more urbanized than they were in the nineteenth century. Whether prevention measures are taken depends on the level of risk which the populations concerned are prepared to accept. These measures should be associated with spatial and temporal forecasts and preceded by an analysis of the processes for these phenomena to be fully understood. In order to remove the ambiguities and the inaccuracies of terminology that are observed all too often, it is necessary in the first instance to define ‘geomorphic hazards and natural risks’, particularly in terms of the notions of risk, hazards, and vulnerability.

French Alps and Alpine Forelands

The French Alps are the western part of the 1,200-km-long Alpine range extending eastward to the Vienna basin. They have the highest summits of the range, in the Mont-Blanc massif (4,807 m a.s.l.). In France, the chain has an arcuate form, convex to the north and west. It lies between Lake Geneva (46° 25′ N) and the Mediterranean coast (approximately 43° 35′ N). The Rhône valley forms a clear geological and morphological western limit. To the north (towards the Jura range) and the south-west (towards the ridges of Provence) the boundary is not so well defined. The French Alps and Alpine forelands have been thoroughly studied for over a century by many researchers from the Universities of Grenoble, Lyons, Aix-en-Provence, Nice, and Chambéry. First, it is necessary to outline the great diversity of landforms in relationship to the complex geological history, tectonics, and lithology. The importance of the Alpine karst landforms and caves must be emphasized; studies of these forms have been extended substantially in the last twenty years and they give many new insights into the Plio-Pleistocene tectonics and climates of this region. The past and present role of glaciers is another important topic in this chapter. From recent studies, we now have a much better knowledge of the transition from the last glacial period to the Holocene. It was impossible to write a chapter on the Alps and ignore the fact that the inhabitants of the Alps have to cope with many permanent natural hazards. The chapter ends with a short synthesis of the main morphogenic systems, which characterize the French Alps and forelands. In the north, the climate is oceanic and precipitation is evenly distributed throughout the year. A high relief, with landforms oriented transverse to the general western atmospheric circulation, results in a great variety of regional climates: from west to east, the continental effect is marked by a decreasing precipitation at the same altitude. Exposure and altitude combine to create contrasting local climates. Temperature inversion is frequent, especially when cold air is trapped in deep valleys.

Danish–German–Dutch Wadden Environments

The Wadden Sea environment is a coastal tidal environment situated between the North Sea and the northwestern European Lowlands. It stretches over a distance of about 450 km from Den Helder in The Netherlands to the peninsula of Skallingen in Denmark. The approximately 10,000 km2 large Wadden Sea is a coastal sediment sink that developed in the course of the Holocene transgression. It resulted from a specific combination of sediment availability (mainly from the North Sea) and a hydrodynamic regime of tides and waves. In its present state, the Wadden Sea environment consists of extensive tidal flats (the wadden), tidal gullies and inlets, salt marshes, and about twenty-four sandy barrier islands. Further, four estuaries exist that discharge into the Wadden Sea. The Wadden Sea may best be characterized by the words ‘dynamic’ and ‘extreme’; dynamic from a geo-morphological point of view, extreme in its biology. According to Spiegel (1997), with each flood phase a tidal energy input in the order of 2.2 thousand MW occurs in the Wadden Sea of Schleswig-Holstein (Germany). This energy input, combined with the energy impact of wind, waves, and storm surges, results in strong morphological processes. Flora and fauna in the Wadden Sea have to adapt to these intense morphodynamics. Further, they have to endure the permanent change of flood and ebb and fluctuations in salinity, as well as high water temperatures during summer and occasional ice cover during winter. As a result of these extreme environmental conditions, a highly specialized biosystem with about 4,800 species has developed (Heydemann 1998). In its present state the Wadden Sea is one of the last remaining near-natural large-scale ecosystems in central Europe. Its ecological significance is underlined by the fact that 250 animal species live exclusively here (Heydemann 1998). Furthermore, nowhere else in Europe is an ecosystem of this size visited by more birds per surface area for the purpose of feeding. However, the Wadden Sea is subjected to considerable human influences, e.g. the input of nutrients and pollutants, fisheries, dredging, boat traffic, and tourism (de Jong et al. 1999).

Urbanization, Industrialization, and Mining

Urbanization, industrialization, and mining are three different responses by mankind to survive, to develop, to create wealth and prosperity, and to organize life. Of the three, mining is the oldest, accessing specific materials provided by nature. Urbanization originally was a community’s means of seeking shelter in a hostile natural environment. The co-operation involved in urbanization also provides benefit to all. Industrialization is the latest of these three processes and aims to concentrate production activities at one spot, which allows for increased scale and higher outputs. Industrialization is often linked with mining and more so with urbanization. Mining is obviously found in confined areas primarily determined by the availability of the required earth materials. Urbanization is determined by a mix of geographical (infrastructure), geological (firm underground and stable conditions), and strategic conditions. Moreover, economic, social, and political factors are increasingly important. The same can be said for the processes leading to the establishment of industrial sites. Urbanization, industrialization, and mining have in common that they not only profit from the environment in which they operate, but also affect the natural balances of that environment. Consequently, these activities generate some response in the subsurface, either small or more significant. In the course of time humankind has faced many of these responses, but they still may cause surprises. This chapter briefly describes the impact of urbanization, industrialization, and mining on the natural environment of north-western Europe, both in terms of assets and threats. Attention is given to monitoring the Earth’s response to these activities through the geological processes involved. For monitoring and prediction substantial information and knowledge of the subsurface is necessary and sources of such data are outlined. The chapter starts with some facts and figures, and is mainly based on Urban Geoscience by McCall et al. (1996). Information is also derived from the State of the Environment reports as published by the European Union. Much more attention is given to urbanization than to either of the other activities. However, since modern, urban, industrialized societies consume large amounts of primary resources, mining, industrialization, and urbanization are closely connected.

Air, Water, and Soil Pollution

The physical environment of western Europe (its air, water, and soil) has been affected by a wide range of pollutants for centuries. Localized pollution of water from anthropogenic sources has been observed since the time of the Roman Empire and by the medieval period cities already experienced air pollution problems. As will be seen, proposals to tackle pollution in the Rhine stretch back to the fifteenth century. However, extensive pollution of the environment was a characteristic of the industrial revolution and major and widespread impacts have been observed throughout the nineteenth and twentieth centuries. Only in the last few decades have the emissions (and, therefore, impacts) of many of these pollutants declined due to measures taken by the countries of the region, both collectively and individually (Farmer 1997). This chapter presents an overview of trends in air, water, and soil pollution. In each case the pollutants of most concern will be discussed, indicating their sources and impacts; locations are indicated in Fig. 19.1. In each case the measures that have been adopted to reduce these pollutants will be described, not least to suggest trends for the future. The monitoring of pollutant emissions, concentrations in the environment, and their specific impacts have generated enormous quantities of data over many years. Basic ‘state of environment’ information is produced at the municipal, regional, national, and international level. The latter includes reports produced by EU institutions, especially the European Commission and the European Environment Agency, as well as other multilateral co-operative institutions such as the Rhine Commission. Severe air pollution sources are concentrated, among other regions, in the traditional heavy industry complexes in north-eastern France, Luxembourg, the Meuse valley in Belgium, and in the huge Ruhr industrial complex in western Germany. The range of air pollutants produced by human activity, as well as the impacts that they cause, are extensive. This section will focus on the following pollutants: ammonia, nitrogen oxides, ozone, particulates, and sulphur dioxide. These result in a range of impacts from direct effects on human health and on vegetation to damage to buildings and materials and acidification and eutrophication of soils and water.