ripple mark


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Related to ripple mark: Cross bedding

ripple mark

[′rip·əl ‚märk]
(geology)
A surface pattern on incoherent sedimentary material, especially loose sand, consisting of alternating ridges and hollows formed by wind or water action.
One of the ridges on a ripple-marked surface.
References in periodicals archive ?
However, ripple marks that could be measured were only observed on two levels--on the upper surface of the Paaskula Member, described in detail below, and in a restricted area in the lower part of the Saue Member of the Kahula Formation.
In the quarry the uppermost bed of the member with ripple marks consists of yellowish-grey seminodular micritic limestones with bioclasts of bryozoans, brachiopods, echinoderm columnals, algae (Fig.
The surface with ripple marks has pyritic impregnation and has been partly eroded before the formation of younger deposits.
Ripple marks in the Vasalemma quarry have flat-topped, sometimes rounded, straight or sinuous crests.
The clearly asymmetric ripple marks occurring in siltstones of the Lower Cambrian Lukati and Tiskre formations have the wavelength of 10-20 cm and RI 3-32 and 5-16, respectively (Pin-us 1971, 1978).
Short wavelengths of ripples and possible occurrence of cross ripple marks have been reported from the Saku Member (L = 10 cm) of the uppermost Vasalemma Formation and from the topmost Ordovician Porkuni Stage (L = 2-4 cm) (Polma 1982).
Ripple marks obviously never appear in sands coarser than 0.
The hardground that was formed on ripple marks served later as the substrate for the colonization of new organisms, for example, the edrioasteroid echinoderm Cyathocystis occurring abundantly in reefs (Fig.
Still, Tanner (1960, 1967) states that morphological features are useless and no real RI can be obtained for flat-topped ripple marks.
3 of the ripple marks in Vasalemma show similarity with the wavecurrent ripples (Tanner 1967; Reineck & Singh 1973).
The sea bottom relief evidently became very differentiated, which caused variation in water flow and the direction of ripple marks.
Ripple marks in the Lower Palaeozoic (Cambrian to Devonian) of Estonia have been described rather briefly on the basis of the wavelength and height.