Podrobnosti záznamu

    Sandstone landforms shaped by negative feedback between stress and erosion
    Bruthans, J.
    Filippi, Michal
    Kletetschka, Günther
    Mašín, D.
    Mayo, A. L.
    Řihošek, J.
    Schweigstillová, Jana
    Soukup, J.
    Vaculíková, J.
Typ dokumentu
    článek v odborném periodiku
Zdrojový dokument - seriál
    Nature Geoscience
    Roč. 7, č. 8
    s. 597-601
    Projekt: GA13-28040S, GA ČR3cav_un_auth*0292643
    Rozsah: 5 s. : P
Předmětová kategorie
    sandstone landsforms
Klíčové slovo
Abstrakt (anglicky)
   Weathering and erosion of sandstone produces unique landforms such as arches, alcoves, pedestal rocks and pillars. Gravity-induced stresses have been assumed to not play a role in landform preservation and to instead increase weathering rates. Here we show that increased stress within a landform as a result of vertical loading reduces weathering and erosion rates, using laboratory experiments and numerical modelling. We find that when a cube of locked sand exposed to weathering and erosion processes is experimentally subjected to a sufficiently low vertical stress, the vertical sides of the cube progressively disintegrate into individual grains. As the cross-sectional area under the loading decreases, the vertical stress increases until a critical value is reached. At this threshold, fabric interlocking of sand grains causes the granular sediment to behave like a strong, rock-like material, and the remaining load-bearing pillar or pedestal landform is resistant to further erosion.
   Our experiments are able to reproduce other natural shapes including arches, alcoves and multiple pillars when planar discontinuities, such as bedding planes or fractures, are present. Numerical modelling demonstrates that the stress field is modified by discontinuities to make a variety of shapes stable under fabric interlocking, owing to the negative feedback between stress and erosion. We conclude that the stress field is the primary control of the shape evolution of sandstone landforms.
    AV ČR Brno, Ústav struktury minerálů a hornin
Kód přispěvatele
Zdrojový formát
Datum importu
    24. 10. 2014