Cross-bedding

<p>In <a href="/facts/Geology/WGvVRIYF">geology</a>, cross-bedding, also known as cross-stratification, is layering within a <a href="/facts/Stratum/w5D4VAwa">stratum</a> and at an angle to the main bedding plane. The <a href="/facts/Sedimentary_structure/8wB6ocm9">sedimentary structures</a> which result are roughly horizontal units composed of inclined layers. The <a href="/facts/Principle_of_original_horizontality/V1CVvseb">original depositional layering</a> is tilted, such tilting not being the result of post-depositional <a href="/facts/Fold_(geology)/WWDL3kjf">deformation</a>. Cross-beds or "sets" are the groups of inclined layers, which are known as cross-strata.
</p><p>Cross-bedding forms during deposition on the inclined surfaces of <a href="/facts/Bedforms/7wfTsh2D">bedforms</a> such as <a href="/facts/Ripple_marks/3PYhXeYh">ripples</a> and <a href="/facts/Dune/Hq26h9hh">dunes</a>; it indicates that the <a href="/facts/Sedimentary_depositional_environment/D9msL28T">depositional environment</a> contained a flowing medium (typically water or wind). Examples of these bedforms are ripples, dunes, <a href="/facts/Antidune/ecLTDQvX">antidunes</a>, <a href="/facts/Sand_waves/UxnUE2V3">sand waves</a>, <a href="/facts/Hummocks/hDe8DxbY">hummocks</a>, <a href="/facts/Shoal/uVP4nYGo">bars</a>, and <a href="/facts/River_delta/fmWuaRqX">delta</a> slopes. Environments in which water movement is fast enough and deep enough to develop large-scale bed forms fall into three natural groupings: rivers, tide-dominated coastal and marine settings.
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Cross-bedding open-in-new

Cross-bedding