See: trough cross stratification and other examples at: dune cross stratification See ripple cross lamination on Mars: martian ripples. Note the planar (also called tabular) cross-bedding. Sketch of three dimensional (sinuous-crested) ripples in a unidirectional flow. Note the trough cross-bedding on the cut that is perpendicular to flow (i. Definition of trough cross-stratification Our online dictionary has trough cross-stratification information from A Dictionary of Earth Sciences dictionary.
Sinuous ripples produce trough cross lamination. They only form when grain diameter is less than.7 mm because bed roughness inhibites the boundary layer separation required for ripple formation. Scour in the trough and on the base of the stoss side supplies the sand, which moves up the gentle slope of the stoss side of the next ripple and so a whole train of ripple troughs and crests advance downstream. Trough cross-bedding formed by the migration of sinuous subaqueous dunes typically has asymptotic bottom contacts and an undulating lower boundary. In geology, the sedimentary structures known as cross-bedding refer to horizontal units that are internally composed of inclined layers. Meaning of cross bedding in the english dictionary online.
Cross bedding forms primarily by migration or ripples and dunes in water or air. Trough cross-bedding consist of cross-bedded units in trough-shaped sets consisting of an elongated scour filled with curved foreset laminae that commonly have a tangential relationship to the base of the set. Competence: the term can have a hydraulic or rheological meaning; in the first respect, it indicates the maximum velocity of a current (related to the size of transported particles); in the second, it is equivalent to strength or resistance to deformation. Festoon: syn. of trough, the basic unit of concave cross-bedding; festoon cross-bedding trough cross-bedding. Cross-stratification, both planar and trough, is the principal directional structure used for paleocurrent analysis. Trough cross-stratification is especially characteristic of fluvial deposits, where it is typically formed by the primary current and correlates strongly with the flow direction (Harms and Fahnestock 1965; Wermund 1965; Williams 1968; Barrett 1970; McGowen and Garner 1970; Dott 1973; Michelson and Dott 1973; High and Picard 1974). Identifying Ordered Strata: Evidence, Methods, and Meaning.
Geology 135 Sedimentation
Official Full-Text Publication: The characterization of trough and planar cross-bedding from borehole image logs on ResearchGate, the professional network for scientists.