Basic types of stratification in small eolian dunes

摘要: The thinnest recognizable strata in modern eolian dune sands can be grouped into six classes. They are herein named planebed laminae, rippleform ripple-foreset crosslaminae, climbing translatent strata, grainfall and sandflow cross-strata. Planebed laminae formed by tractional deposition on smooth surfaces at high wind velocities. very rare the deposits studied. Grainfall also surfaces, largely zones of flow separation. much more common than which they closely resemble. Eolian climbing-ripple structures composed primarily trans-latent each is depositional product a single ripple. Climbing that relatively or supercritical angles ripple climb typically accompanied wavy layers parallel to rippled surfaces. Ripple-foreset incomplete produced when angle low subcritical, rarely visible sands. Sandflow cross-strata avalanching noncohesive sand slipfaces. Their form varies with slipface height other factors.