Morphologies karstiques et fantômisation

Abstract

Underground karst morphologies are often used by scientists to speculate on the conditions of formation of karst cavities, for example: flow in vadose or phreatic zone, flow on sedimentary filling and fluvial flow. However, recent development of the ghostrock karstification models provides new insights on the origin of these morphologies. For ghostrock karstification, the chemical dissolution of calcite is coming along with the drainage of the soluble species while the undissolved particles remain unremoved. On the other side, karstification by total removal, undissolved particles are simultaneously eroded from the system leading to the creation of a macroscopic void. This paper presents numerous field observations of karst morphologies, which were previously considered as resulting of karstification by total removal, in ghostrock karstification context. From them, it has been demonstrated that most karst morphologies may result from both processes, which requires great caution in the interpretation of these microforms.