Morphology, ice types and thermal regime in a high mountain ice cave. First studies applying Terrestrial Laser Scanner in the Peña Castil ice cave (Picos de Europa, Northern Spain)

Abstract

The Picos de Europa form the highest massif of the Cordillera Cantabrica, northwestern Spain. It is a high mountain belt (1800 to 2650 m) which is characterized by a nivoperiglacial morphodymanic and periglacial conditions in its upper part (above 2200 m). Its sharp topography, climatic conditions, thick carboniferous limestones and large altitude differences provide the environment for a highly developed mainly vertical endokarst in which ice caves are commonplace. Geomorphological studies on ice caves that go beyond topographic descriptions are so scarce as to be practically non-existent. The application of Terrestrial Laser Scanner (TSL) technology is crucial to monitor cave ice evolution, ice flow and for surveying specific cave morphologies. Preliminary temperature data obtained for the Peña Castil ice cave by dataloggers inside the cave and from an automatic meteorological stations outside show a static behaviour of the cave with two main periods (open and closed) and two secondary ones (transitional periods). The zonal distribution of temperatures shows differing behaviour in the cave as we move away from the influence of the ice deposit. There is a main ice accumulation period linked to snow cover melt (peaking at the beginning of June) which is characterized by large cryospeleothems and a visible refreezing cap on the ice body surface. In late fall or early winter, the ice body is weakest. Likewise, we identified different ice structures and cryospeleothems based on their origin and crystallization process, and highlighted those observed for the first time in the Picos de Europa, e.g the radicular crystallization hoarfrost.