Cave genesis in the Alps between the Miocene and today: a review

摘要

Progress in the understanding of speleogenctic processes, as well as the intensive research carried out in the Alps during the last decades, permit to summarise the latest knowledge about Alpine caves. The phreatic parts of cave systems develop close to the karst watertable, which depends on the spring position, which in turn is generally related to the valley bottom. Thus, caves arc directly linked with the geomorphic evolution of the surface and reflect valley deepening. The sediments deposited in the caves help to reconstruct the morphologic succession and the paleoclimatic evolution. Moreover, they arc the only means to date the caves and thus the landscape evolution. Caves appear as soon as there is In emersion of limestone from the sea and a watertable gradient. Mesozoic and early Tertiary paleokarsts within the Alpine range prove of these ancient emersions. Hydrothermal karst seems to be more widespread than previously, presumed. This is mostly due to the fact that usually, hydrothermals caves are later reused (and reshaped) by meteoric waters. Rock-host weathering is described as a new speleogenetic agent. On the contrary glaciers hinder speleogenetic processes and fill caves with sediment. They mainly influence speleogenesis Indirectly by valley deepening and abrasion of the caprock. All present datings as well as morphological indications suggest that many Alpine caves (excluding palcokarst) arc of Pliocene or even whocene age. Progress in dating methods (mainly the recent evolution with cosmogenic nuclides) should permit, in the near future, to date not only Pleistocene, but also Pliocene cave sediments absolutely.