Géotope, géofacies et géosystème : une grille de lecture des paysages géomorphologiques ? Le cas de la Réserve naturelle nationale des Aiguilles Rouges, Chamonix-Mont-Blanc (Haute-Savoie, France)

Abstract

Using the scenery provided by the glacial Lac des Chéserys (Figure 1) as a supporting example (Aiguilles Rouges National Nature Reserve, France), we discuss the concept of landscape value by combining the sliding scale of landscape analysis developed by G. Bertrand (1968) with more recent approaches that have emerged with the promotion of geomorphological important sites, or geomorphosites, as natural heritage (Panizza et Piacente, 2003. Reynard et al., 2009). We first elaborate on the semantic distinction between landscape and geomorphic landscape, and through a comparative examination of the views of Ruskin and Viollet-le-Duc on Mont-Blanc in the 19th century we revisit the concepts of scientific value, of additional value, and discuss the benefits of popularised science for the outdoor industry. We go on to review perceptual filters in landscape appreciation and propose a distinction between cultural filters and functional filters (Table 1). These issues are then illustrated with a worked example in which the concept of landscape value is tied to a geomorphosite where the field of view combines near-field and far-field landforms. This situation corresponds to a common occurrence along panoramic footpaths in mountain ranges (Table 2). We compare a typical postcard image of an alpine landscape near Chamonix (Figure 2) with a more didactic image of scenery nearby (Figure 3). Irrespective of viewing point elevation, we find that all lookout points from the Chamonix side of the Aiguilles Rouges massif offer views of Mont-Blanc that are of approximately equal quality. The total value of the distant landscape component varies therefore very little. The global value of a geomorphosite in such a setting will thus depend more heavily on the nature of the features located in the foreground : the need to select optimal locations, i.e. those that will be of greatest scientific and/or educational interest, then cannot avoid a systematic survey. Given that the focus of any observer will switch back and forth from the near-field objects of the foreground to the panoramic vistas of the horizon, we discuss how the encapsulation of maximum space-and time-depth in a single field of vision can be put to best advantage, and summarize the complex and dynamic succession of natural and human forces that were involved in producing the alpine landscape under scrutiny (Table 3).