Climbing ripple laminations

Describing climbing ripple laminations in simple language

1. Climbing Ripple Laminations Prathamesh S. Pawar M.Sc. (I) Geology, Dept of Geology S. P. Pune University

2. A series of cross- laminae produced by superimposing migrating ripples . Ripples climb on one another such that the crests of vertically succeeding laminae are out of phase . They appear to be advancing upslope. What are climbing ripple laminations?

3. Types Classification based on the angle of climbing and stoss side angle Sub-critically climbing ripples: angle of climbing < stoss side angle 2. Critically climbing ripples: angle of climbing = stoss side angle 3. Super-critically climbing ripples: angle of climbing > stoss side angle

4. How are they formed? Formed when deposition takes place very rapidly during migration of ripples. Formed because deposition exceeds migration. Cross- laminae are produced by superimposing migrating ripples.

5. Conditions for formation of Climbing ripples Abundant sediments , especially sediments in suspension, which quickly buries and preserves original rippled layers Abundant suspended sediment supply must be combined with just enough traction transport to produce rippling of the bed, but not enough to cause complete erosion of laminae front the stoss side of ripples

6. In-phase climbing ripples (Rare Case) Some ripple laminae may be in phase (one ripple crests lies directly above the other), indicating that the ripples did not migrate . In-phase ripple laminae form under conditions where a balance is achieved between traction transport and sediment supply and are balanced so that the ripples do not migrate despite a growing sediment surface .

7. Occurrence/ Environments Occurs in sediments deposited in environments characterized by rapid sedimentation from suspension, e.g.- Fluvial flood plains Point bars River deltas Turbidite deposits

8. Thank you…