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A bedding surface is three-dimensional surface, planar or curved, that visibly separates each successive bed (of the same or different lithology) from the preceding or following bed. Where bedding surfaces occur as cross-sections, e.g., in a 2-dimensional vertical cliff face of horizontal strata, are often referred to as bedding contacts .
Graded bedding is a sorting of particles according to clast size and shape on a lithified horizontal plane. The term is an explanation as to how a geologic profile was formed. Stratification on a lateral plane is the physical result of active depositing of different size materials.
The bedding surfaces (bedding planes) that separate strata represent episodic breaks in deposition associated either with periodic erosion, cessation of deposition, or some combination of the two. [ 3 ] [ 4 ] Stacked together with other strata, individual stratum can form composite stratigraphic units that can extend over hundreds of thousands ...
Structural geologists measure a variety of planar features (bedding planes, foliation planes, fold axial planes, fault planes, and joints), and linear features (stretching lineations, in which minerals are ductilely extended; fold axes; and intersection lineations, the trace of a planar feature on another planar surface).
When this happens the rock fractures in a plane parallel to the maximum principal stress and perpendicular to the minimum principal stress (the direction in which the rock is being stretched). This leads to the development of a single sub-parallel joint set. Continued deformation may lead to development of one or more additional joint sets.
These structures are within sedimentary bedding and can help with the interpretation of depositional environment and paleocurrent directions. They are formed when the sediment is deposited. Cross-bedding Cross-bedding is the layering of beds deposited by wind or water inclined at an angle as much as 35° from the horizontal. [1]
Bedding planes and structural features such as faults, folds, are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features. Stratigraphic contour lines may be used to illustrate the surface of a selected stratum illustrating the subsurface topographic trends of the strata.
Various geological processes create discontinuities at a broadly regular spacing. For example, bedding planes are the result of a repeated sedimentation cycle with a change of sedimentation material or change in structure and texture of the sediment at regular intervals, folding creates joints at regular separations to allow for shrinkage or expansion of the rock material, etc. Normally ...