Neue Ergebnisse zur Gletscher- und Klimageschichte des Spätmittelalters und der Neuzeit

Abstract

This article contributes to the glacier and climatic fluctuations during the late Middle Ages and the Modern Times. With the aid of radiocarbon dating of fossil woods and a fossil soil (fAh) located in the gletschervorfeld of two glaciers (Glacier de Zinal and Riedgletscher, Valais), the foUowing glacier advances could be shown: between 890 yBP and 1095 yBP, at 515 yBP, in the seventeenth and in the nineteenth Century. The tree rings from a larch (Larix decidua Mill.) near the glacier and the tree line (Riedgletscher, 2180 m altitude) was analysed by the X-ray densitometry. The maximum density of the annual rings reflects the summer temperatures since the middle of the twelfth Century. The fluctuations of the maximum density shows a close interrelation with the fluctuations of the Grosser Aletschgletscher (Valais). The local climatic influence of the Riedgletscher during maximal extension is visible in reduced tree-growth. During the retreat phase, when the glacier melted back, the regional climate dominates the tree-growth again.