Cross bedding

Kreuzgelenk, n. universal joint, kreuzgeschichtet, a. cross-bedded. 

FIGURE 3.7 Diagram showing effects of sedimentary structures and textures on the flow of fluids in a point-bar sandstone reservoir. The cross-bedded unit is coarser grained and is inferred to have better reservoir properties (i.e., permeability) than the overlying rippled unit (A). Uneven advance of injected fluids illustrating permeability variations results from differences in reservoir quality. (Modified after Ebanks, 1987.)... 

CARNOTITE, This mineral is a vanadate of potassium and uranium with small amounts of radium. Its formula may be written K (UCL) (VOah JHsO. The amount of water, however, seems to be variable. It occurs as a lemon-yellow earthy powder disseminated through cross-bedded sandstones with rich concentrations around petrified and carbonized trees. Soft sp gr 4.7. It was mined in Colorado and Utah as a source of radium. Other localities are in Arizona. Pennsylvania, and Zaire. 

Mackenzie F.T. (1964b) Geometry of Bermuda calcareous dune cross-bedding. Science 144, 1449-1450. 

CH Channel + levee Trough cross-bedded sand (St) planar laminated sand (Sp) low angle cross-bedded sand (SI) horizontally laminated sand (Sh) ripple cross-laminated sand (Sr) massive sand (Sm) massive, crudely bedded silts and muds (Fm) finely laminated to rippled silts and muds (FI) laminated silt, sand, and clay (Fsc) Tabular to lenticular 0.2-3 m thick 10 m to >2 km in lateral extent Fine to coarse, moderately sorted sand/sandstone Type 1 and type 3 (phreatic) tabular units... 

EC Cross-stratified aeolian dune bodies Trough cross-bedded sand (Ste) planar laminated sand (Spe) low angle cross-bedded sand (Sle) horizontally laminated sand (She) ripple cross-laminated sand (Sre) massive sand (Sme) Tabular, lenticular and wedge-shaped 1-3 m thick > 1 km lateral extent Fine to lower coarse, moderately to well sorted sand/sandstone Scattered ovoid to elongate concretions and small type 1 and type 3 phreatic tabular units... 

Sedimentary structures such as trough and planar cross-bedding are common features of type 1 tabular cemented units (Fig. 1 lA). These cemented units are coarser grained and better sorted than units immediately below and above (Fig. 6). Lower contacts are most often sharp and locally erosive. Upper contacts are usually sharp. Bed outlines can be lenticular, wavy and irregular, depending on the original sedimentary structures preserved. These units are usually associated with channel associations (CH), and coarser, better sorted units in crevasse splay deposits (Table 1 Fig. 6). They vary from 0.2 to 3 m in thickness and can be of great lateral extent (> 1 km) (Fig. 7). Calcite cementation textures are mainly blocky spar. Coalesced ovoid... 

Scott (1990). The low-angle beds consist mainly of laminated or cross-bedded and hummocky cross-bedded sandstone with a ripple-laminated upper part that has wavy clay bedding. The ripple and wavy bedded upper part can be caused by deposition under waning flow conditions, but can also be the result of wave reworking. In the intermediate area, where the delta complex is storm and wave dominated, lenses are abundant (Berners, 1985). 

Current structures, such as dune bedding, ripples and cross-bedding, are sometimes found in limestone. They were produced by the fossilisation of features produced in sediments which had been subjected to limited transport by water currents. 

Figure 4, The displacement of multiple nonreactive tracers through the Ringold Formation under saturated and unsaturated conditions, (a) Displacement through a horizontal core of the horizontally-bedded Ringold Formation, (b) Displacement through a vertical core of the cross-bedded Ringold Formation. Reproduced with permission from reference 24. Copyright 2002 Elsevier...

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