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These commonly form in fluvial and aeolian depositional environments, and are a signifier of the lower part of the Lower Flow Regime. Ripple cross-laminae forms when deposition takes place during migration of current or wave ripples. A series of cross-laminae are produced by superimposing migrating ripples.
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.
Wave ripple or symmetric ripple, from Permian rocks in Nomgon, Mongolia with "decapitation" of ripple crests due to change in current. Ripple marks usually form in conditions with flowing water, in the lower part of the Lower Flow Regime. There are two types of ripple marks: Symmetrical ripple marks
Baraboo Quartzite may display strata created by progressive deposition of layers of sand in the original sandstone from which the quartzite was formed (through metamorphism). [2] Specimens of Baraboo quartzite may also display ripple marks that appear visually similar to the patterns one might see in the sand at a beach. Ripples indicate that ...
Ripple marks: Ripple marks are small ridges of sediment that form due to wind or water blowing over loose sediment in either a current or wave pattern. Aeolian ripples result from high velocity winds which form fine, well-sorted grain particles into long, flat, asymmetrical ripples. [citation needed]
Classic, low-density turbidites are characterized by graded bedding, current ripple marks, climbing ripple laminations, alternating sequences with pelagic sediments, distinct fauna changes between the turbidite and native pelagic sediments, sole markings, thick sediment sequences, regular bedding, and an absence of shallow-water features. [3]
The name was introduced by Harms et al. in 1975. Before this time, these structures were recognized under many different names. When hummocky cross-stratification was founded, it was originally given the name "truncated wave-ripple laminae", by Campbell (1966, 1971). [1]
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]