Wave Ripple Cross Lamination

Each ripple migrated producing unidirectional cross lamination.

Wave ripple cross lamination.

Wind ripple lamination generally comprises thin 1 10 mm parallel laminae defined by slight changes in grain size. Ancient wave ripple lamination and hummocky cross stratification. However the individual ripple cross sections are symmetric characteristic of wave action. Ripples formed by a combination of wave action and unidirectional flow.

Interference ripple sets silurian clam bank formation port au port peninsula nfld. These wave ripple cross laminations are less clearly symmetric. Lensoid and complexly interwoven cross sets. Medium cross lamination are ripples with a height greater than ten centimeters and less than one meter in thickness.

Wave ripple cross lamination formed in a sandy lacustrine shoreface in the canadian great lakes is characterized by i small randomly superimposed sets of angle of repose cross lamination with strongly bimodal dips. Grain avalanches down lee slopes result in small scale cross lamination. The ripples form lateral to one another such that the crests of vertically succeeding laminae are out of phase and appear to be advancing upslope. Ii small superimposed sets of angle of repose cross lamination where the thickest and most prevalent sets have onshore dips and the thinner subsidiary sets dip offshore.

Ripple cross laminae forms when deposition takes place during migration of current or wave ripples. Unidirectional cross laminae sometimes with drapes sand laminae oriented in the opposite direction. Wind ripples commonly have coarser grains on their crests and this is reflected within wind ripple laminae which show inverse grading coarsening upward slightly within laminae. Sections normal to flow may be horizontal defining planar cross lamination 2 d ripples or may be trough shaped defining trough cross lamination 3 d ripples.

A series of cross laminae are produced by superimposing migrating ripples. Wave ripple cross lamination the form of cross lamination see cross stratification produced by the migration of wave generated ripples or combined flow ripples i e. Ancient ripple lamination figure pageindex 22.