L’evoluzione dei ghiacciai, del paesaggio e del clima nei Monti di Tures (Alto Adige) dal Tardiglaciale

Glaciers, landscape and climate evolution in the Mountains of Taufers (South Tyrol) since the Late glacial

Abstract

Main results of a study of the history of glaciers, landscape and climate since the Lateglacial in the Rieserferner Mountains (Mountains of Taufers, 46°55’N/12°07’E) are briefly presented. The research work carried out since several years is based on geomorphological and dendrochronological methods and investigations in botanical geography. In the course of the LateGlacial the Equilibrium Line Altitude (ELA) in the research area was lower of about 690 m during the glacial stage of «Steinach» and 210 m during the glacial stage of «Egesen» with reference to the altitude of 1850 AD (BZN). The lower boundary of alpine permafrost was about 770-610 m lower than today. During the dry-cold Late-Glacial period the precipitation reached about 60-70% of the today’s amount. The climatic conditions caused a high rate of weathering on rock-walls in a range of 7-12 mm/year, which decreased to 0,9-1,6 mm/year during the Holocene. In the course of the Holocene the glaciers in the research area never showed a clearly larger extension than at the time of the «Little Ice Age»-maximum at about 1850 AD. Older Holocene ice margin deposits are only locally developed. The glacier retreat following the 1850^th was interrupted within the periods about 1890-1900, about 1920 and about 1970-80. Until 1985 an increase of ELA of about 100 m/BZN could be calculated, while the glaciated area decreased by 51 % and the volume of glacial ice even by 70%. During the Holocene the forest in the mountains of Taufers was affected by climatic and anthropogenic influences. Repeated lowerings of the timberline of about 60-100 m took place due to changes of climate. The clearing of mountain pasture caused a widespread lowering of the timberline of about 200-350 m.