Planar Laminated Sandstone

In geology cross bedding also known as cross stratification is layering within a stratum and at an angle to the main bedding plane.

Planar laminated sandstone.

Covered with a thin layer of plastic to protect it. In geology lamination is a small scale sequence of fine layers laminae. The depositional environment for this unit was slow settling i e fallout without traction. The term parallel lamination has also been used to describe laminae with parallel but nonplanar boundaries figure p11.

Laminated light yellow to yellow colored parallel laminated sl sandstone in the middle and plannar cross stratified grayish white sandstone sp at the top chandimura section on lalmai hills. Typically the undulation shows no evidence of lateral accretion but only vertical aggradation and as a result most beds consist of a single laminaset. Alternating episodes of deposition from high energy winds and. The horizontally bedded sandstone represents a damp sand sheet the surface of which would have been covered by a microbial mat.

Micaceous particles would fall more slowly owing to their shape thus aggregating on bedding. Consisting of several thin layers of. On parting surfaces through planar laminated sandstones parting lineation also called somewhat more precisely parting step lineation is characteristic presumably reflecting a tendency for flow parallel orientation of slightly elongated particles under upper flow regime conditions. A laminated sandstone layer with tabular form interbedded with the cross stratified sandstone element ae1.

Sandstone beds are characterized by a peculiar planar lamination showing a subtle although perceptible undulation. Planar laminated sandstones popularly known. The sedimentary structures which result are roughly horizontal units composed of inclined layers. Hence planar lamination has also been called horizontal lamination even lamination and parallel lamination.

Spacing to height ratios of the undulation are generally 100 or more. Lamina that occurs in sedimentary rocks laminae are normally smaller and less pronounced than bedding lamination is often regarded as planar structures one centimetre or less in thickness whereas bedding layers are greater than one centimetre. B detail of wrinkled horizontal laminae. The sandstone is planar laminated and in some places ripples can be seen.

The origin of planar lamination in sands and sandstones. However structures from several millimetres to many centimetres. The original depositional layering is tilted such tilting not being the result of post depositional deformation cross beds or sets are the groups of inclined.