Palaeo-yardangs: wind-scoured desert landforms at the Permo-Triassic unconformity

Authors

  • DAVID W. TEWES,

    1. Department of Geology, University of Nebraska, Lincoln, NE 68588–0340, USA
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    • *

      Nebraska Department of Environmental Control, 301 Centennial Mall South, Lincoln, NE 68509, USA.

  • DAVID B. LOOPE

    Corresponding author
    1. Department of Geology, University of Nebraska, Lincoln, NE 68588–0340, USA
      †To whom correspondence should be addressed.
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†To whom correspondence should be addressed.

ABSTRACT

In Canyonlands National Park, south-east Utah, at least 29 partly exhumed, aligned sandstone ridges trending generally N20°W occur at the upper unconformable surface of the Lower Permian (Leonardian) White Rim Sandstone. The ridges are at least 1·5 km long, 250 m wide and have up to 14 m of vertical relief (mean of 9 m). A thin lag of coarse sandstone that contains wind-ripple laminae and granule ripples directly overlies the ridges. Angular blocks of sandstone within the lag and sand-filled fissures immediately below the lag, within the ridges, attest to early cementation of the ridge-forming material. SE-dipping aeolian cross-strata within the White Rim Sandstone and within the lag closely parallel the ridge trend. The ridges are interpreted as wind-sculpted desert landforms (yardangs) that developed on the lithified upper surface of the White Rim Sandstone during an extended period of hyperaridity towards the end of the Permian.

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