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A QUANTITATIVE MODEL OF CLIMBING RIPPLES AND THEIR CROSS‐LAMINATED DEPOSITS
Author(s) -
ALLEN J. R. L.
Publication year - 1970
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1970.tb00179.x
Subject(s) - ripple , lamination , climb , geology , bed load , flow (mathematics) , sediment , climbing , deposition (geology) , ripple marks , sediment transport , geotechnical engineering , mechanics , geomorphology , geometry , materials science , thermodynamics , mathematics , engineering , power (physics) , physics , structural engineering , layer (electronics) , composite material
SUMMARY The angle of climb of ripples in cross‐laminated deposits is governed by the simple relation: in which ζ is the angle of climb, M is the rate of sediment deposition normal to the rippled bed, H is the ripple height, and jb is the bedload sediment transport rate. After introducing sediment transport functions, this relation is developed using the assumptions of gradually varied flow to predict the spatial patterns of cross‐lamination types in deposits due to pure non‐uniform flow, pure unsteady flow, and simultaneous non‐uniform and unsteady flow. Most of the predicted patterns can be matched from the geological record, and the analysis affords a hitherto missing insight into the environmental significance of climbing‐ripple cross‐lamination. The analysis also results in a rigorous definition of the kinds of environmental interpretation that may legitimately be made from examples of this structure.