Abstract

Glaciers are known, among their many features, for being great landscape sculptures. The erosive force of their advance and retreat leaves morphological prints such as moraines, glacial cirques, flutes, among others. These elements are clear indications of both past and present glacial environment and favour the understanding of the processes that originates a high mountain relief. Despite the latter, there are other phenomena derived from the glacial environment that can have a sudden and intense impact on the landscape. Such is the case of glacier-related mass movements. These include rock and ice avalanches, glacier catastrophic detachments, glacier surges and Glacial Lake Outburst Floods. Similarly, debris flows originated from active rock glacier fronts also constitute examples of the latter. This contribution analyses several cases of mass movements that occurred in the last century in the central Andes of Chile (30°S-35°S). Firstly, the effects of the 1947 surge of the Juncal Sur Glacier (33.10°S/70.11°W) on the headwaters of the Olivares River valley are assessed, whose glacial striations are still recognisable today. At nearly the same site, the result of a 1992 glacier advance originated from a small valley glacier beneath the south face of Cerro Risopatrón (33.16°S/70.07°W) is reported, whose hummocky deposit lies at the end of the Juncal Sur Glacier surging front. At the same time, geomorphological evidence is presented after the 1980 catastrophic detachment of Aparejo Glacier (33.56°S/70.01°W), in the form of glacial striations and flutes, which extremely resemble the pre-detachment condition in 1956 suggesting a possible previous event with similar proportions. This condition is also evident on the Tinguiririca 3 Glacier (34.78°S/70.31°W), in the form of a potential collapse prior to 1970. Finally, the impact of a debris flow originating from the glacier front of the CL105400105 rock glacier (33.01°S/70.08°W) is also reported. The event, which occurred in January 2024, left a marked debris imprint on the Juncal Norte Glacier, whose potential effects on the glacier remain to be assessed. Based on the analysed evidence, we state that it is possible to distinguish between geomorphologic features of different glacier-related mass movements coexisting in a single location. We also propose that large glacier hazards can overthrow the imprint of long-term glacier changes, posing a higher controlling factor for landscape building. Analysing these phenomena is relevant for the evaluation of the recurrence of mass movements in cryospheric environments, to understand their causes, and to estimate their magnitude in high mountain areas.