Geological Museum KIGAM

Bedding Bedding is the arrangement of a sedimentary rock in layers (beds) of varying character such as differing grain size and contrasting color. Bedding is classified as either horizontal bedding or cross-bedding. Formation of bedding is dependent on environmental elements during sedimentation such as depth of transporting water and direction and velocity of transport. Clay, sand and gravel which are transported by water or wind, are deposited at places where the current velocity decreases or stops such as on a stream bed(gravel) or on the bottom of a deep lake or sea(clay). Parallel bedding comprises beds or layers in a sediment that are parallel to each other and to the base of the sedimentary unit. Cross-bedding, often recognized in the cross sections of ripple marks and sand dunes, is characterized by sets of beds at an angle to the main planes of stratification. Cross-bedding forms in the settings of continuous flow, and is useful in interpreting the direction and strength of flow at the time of deposition.

Mud crack & Rain Print Mud varies greatly in volume, expanding or shrinking depending upon the water content. Muddy sediments on shallow mud flats may be cracked into many polygons by loss of water content upon long exposure to sunlight. Sometimes, raindrops leave rain prints on the surface of unconsolidated mud during a very short shower of rain. Cross sections of the beds with mud-cracks may indicate their upper and lower sides because each crack, filled with sand, narrows downwards.