kruisbedding

Kruisbedding, known in English as cross-bedding, is a sedimentary structure characterized by inclined layers that cut across the overall horizontal bedding of a rock. The inclined units, or foresets, form as sediment is deposited on the downwind or downstream face of migrating dune or ripple forms, producing stacked, dipping sheets within a single stratigraphic bed.

Cross-bedding develops in environments where a unidirectional flow moves sediment, most commonly in aeolian dune fields and in subaqueous settings such as rivers, deltas, and shallow marine sand bodies. The dip angle, thickness, and spacing of the foresets reflect factors including flow velocity, grain size, and the rate of dune or ripple migration.

Key features include the directionality of the cross-beds, which records the paleocurrent or paleowind direction, and the presence of multiple cross-bed sets that may dip in the same or different directions within the same bed. Cross-bedding can be categorized by geometry (for example planar or trough cross-bedding) and by scale, ranging from macroscale layers that are visible with the naked eye to microscale laminations identifiable only under magnification.

Occurrence and significance: Cross-bedding is most commonly preserved in sandstones but can occur in other clastic rocks. It is widely used to interpret depositional environments and ancient flow regimes, providing insights into paleoenvironments, paleogeography, and sediment transport. In petroleum geology, cross-bedded sandstones are important because their geometry can influence reservoir quality and fluid flow, guiding exploration and development.