wandellagen

Wandellagen is a term used in stratigraphy to describe a pattern in layered rocks where bedding surfaces appear to migrate or wander laterally across an outcrop or map view, rather than forming a uniform, continuous sequence. The concept is descriptive and observational, applied when layer contacts curve, tilt, or shift position over distance, producing a meandering arrangement of similar lithologies.

Etymology and usage

The name derives from the element wand- (to wander) combined with lagen (layers), reflecting the visual impression of drifting or shifting layers. In practice, wandellagen denotes a qualitative feature in sedimentary sequences rather than a formal lithostratigraphic unit; it is used to understand depositional dynamics and post-depositional deformation that influence the apparent geometry of beds.

Formation and indicators

Wandellagen can arise from several processes, including migrating sedimentary lobes in deltaic or fluvial settings, shifting dune or ripple fields in aeolian environments, and localized tilting or fault-related deformation after deposition. Field indicators include non-planar bed interfaces, lateral offset of otherwise correlative beds, and difficulties in correlating beds across distance, sometimes accompanied by changes in grain size or color that track along a wandering path.

Significance and examples

The concept helps interpret past depositional environments and paleogeography when beds do not present a simple, flat architecture. Examples are reported in shoreline-proximate deltaic successions and dune-field deposits where growth or movement of depositional elements creates a zigzag or serpentine arrangement of beds.

See also: stratigraphy, sedimentology, cross-bedding, lateral continuity, depositional dip.