Gleithlinie

Gleithlinie, literally “glide line,” is a geomorphological term used in German-speaking geology to describe a boundary on a slope where gravitational movement or deformation of material changes behavior. The line is not a fixed geological fault or a precisely measurable feature, but an interpretive boundary that helps characterize slope processes and landforms.

In slope stability and landscape analysis, the Gleithlinie marks where movement regimes shift—for example between relatively stable bedrock above and zones of loose debris, creeping soil, or talus below. It may correspond to the upper limit of active rockfall, to the transition between frost-affected, mobile material and more inert deposits, or to the boundary separating different depositional or erosional regimes on a hillside. The exact placement of the line can depend on local geology, climate, moisture, vegetation, and historical landform development.

Because terminology and emphasis vary among authors and regions, Gleithlinie tends to be used as a descriptive, interpretive concept rather than a precisely defined geometric feature. It is often employed in field mapping, hazard assessment, and the reconstruction of periglacial or mass-wasting processes in mountainous terrain.

See also: talus, landslide, slope stability, periglacial processes.

Etymology: Gleiten (to glide) + Linie (line).