Search results
Results from the WOW.Com Content Network
Ancient wave ripple marks in sandstone, Moenkopi Formation, Capitol Reef National Park, Utah In geology , ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime ) and indicate agitation by water ( current or waves ) or directly by wind .
This creates ripple marks with pointed crests and rounded troughs, which aren't inclined more to a certain direction. Three common sedimentary structures that are created by these processes are herringbone cross-stratification, flaser bedding, and interference ripples. Asymmetrical ripple marks These are created by a one way current, for ...
In sedimentology, wave-formed ripples or wave-formed ripple marks are a feature of sediments (sandstones, limestones, siltstones) and dunes. These ripple marks are often characterised (and thus distinguished from current ripples ) by symmetric cross sections and long relatively straight crests, which may commonly bifurcate.
Bidirectional wave ripple, Nomgon, Mongolia. A paleocurrent or paleocurrent indicator is a geological feature (typically a sedimentary structure) that helps one determine the direction of flowing water in the geologic past. This is an invaluable tool in the reconstruction of ancient depositional environments. [1]
Other MISS include sinoidal structures, polygonal oscillation cracks, multidirected ripple marks, [9] erosional remnants and pockets, or gas domes. Although these structures have only recently been named and systematically described, links between microbes and distinctive structures in sediments and sedimentary rocks have been suggested by ...
As a consequence, a slightly different set of sedimentary structures develops in turbidites deposited by high-density turbidity currents. This different set of structures is known as the Lowe sequence , which is a descriptive classification that complements, but does not replace, the Bouma sequence.
A way up structure, way up criterion, or geopetal indicator is a characteristic relationship observed in a sedimentary or volcanic rock, or sequence of rocks, that makes it possible to determine whether they are the right way up (i.e. in the attitude in which they were originally deposited, also known as "stratigraphic up" or "younging upwards") or have been overturned by subsequent deformation.
Ripple marks: High: Small, cm-scale undulations Sand waves: Medium to low: Rare, longer wavelength than ripples Dunes/Megaripples: High: Large, meter-scale ripples Upper: Upper plane bed: High: Flat laminae, +/- aligned grains (parting lineations) Antidunes: Low: Water in phase with bedform, low angle, subtle laminae Pool and chute: Very low ...