Ripple cross-lamination

The gravels, sands and clays in Reed Chamber in the lowermost epiphreatic level undoubtedly represent fluvial sediments deposited by the stream flowing through the cave at the time, as the sands occasionally show ripple cross-lamination. 

CH Channel + levee Trough cross-bedded sand (St) planar laminated sand (Sp) low angle cross-bedded sand (SI) horizontally laminated sand (Sh) ripple cross-laminated sand (Sr) massive sand (Sm) massive, crudely bedded silts and muds (Fm) finely laminated to rippled silts and muds (FI) laminated silt, sand, and clay (Fsc) Tabular to lenticular 0.2-3 m thick 10 m to >2 km in lateral extent Fine to coarse, moderately sorted sand/sandstone Type 1 and type 3 (phreatic) tabular units... 

EC Cross-stratified aeolian dune bodies Trough cross-bedded sand (Ste) planar laminated sand (Spe) low angle cross-bedded sand (Sle) horizontally laminated sand (She) ripple cross-laminated sand (Sre) massive sand (Sme) Tabular, lenticular and wedge-shaped 1-3 m thick > 1 km lateral extent Fine to lower coarse, moderately to well sorted sand/sandstone Scattered ovoid to elongate concretions and small type 1 and type 3 phreatic tabular units... 

The Namorado Sandstone is composed primarily of massive fine- to very fine-grained arenites. Sedimentary structures are rare, but occasional normal grading is observed. The fluidization process is identified by unusual dish and pillar structures. Rarely, individual beds present ripple cross-laminated divisions at the top. Individual beds have an average thickness of Im. Several individual beds may be amalgamated, resulting in sandy intervals up to 10 m thick. Individual beds or cycles are capped by thin beds of shales and calcilutites. 

C. Ripple cross-laminated fine-grained sandstone that formed at lower current velocities than layers A and B... 

Scott (1990). The low-angle beds consist mainly of laminated or cross-bedded and hummocky cross-bedded sandstone with a ripple-laminated upper part that has wavy clay bedding. The ripple and wavy bedded upper part can be caused by deposition under waning flow conditions, but can also be the result of wave reworking. In the intermediate area, where the delta complex is storm and wave dominated, lenses are abundant (Berners, 1985). 

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