Record details

    Cementation and blackening of Holocene sands by peat-derived humates: A case study from the Great Dune of Pilat, Landes des Gascogne, Southwestern France
    Havelcová, Martina
    Machovič, Vladimír
    Suchý, V.
    Sýkorová, Ivana
    Trejtnarová, Hana
    Zeman, Antonín
Publication type
    článek v odborném periodiku
Source title - serial
    International Journal of Coal Geology
    Roč. 114, JUL
    s. 19-32
    Projekt: GA13-18482S, GA ČR, CZ3cav_un_auth*0292152
    Projekt: GA205/09/1162, GA ČR3cav_un_auth*0254057
    Rozsah: 14 s. : P
Subject category
    aeolian sand
Abstract (in english)
   The base sand layers of the aeolian Great Dune of Pilat, which stretches along the coast of Arcachon Bay, have been locally impregnated with a dark brown to black amorphous organic substance of humate composition. The humate-cemented sand forms a well-indurated horizon 40-50 cm in thickness that developed immediately beneath the Holocene peaty layer (P1 "paleosoil"). The humate, identified by means of FT-IR and Raman micro-spectroscopy, acted both as a cementing agent and as a coloring agent; it formed thin coats and meniscus cements between individual sandstone grains which, in turn, caused the dark, asphaltic-like appearance of the sandstone.
   Field observations, combined with geochemical analyses, and the presence of identical geochemical compounds recognized in the peat and sandstone humate cement, suggest that the peat-containing low-coalified (R-r = 0.2%) fragments of higher, submerged and floating plants and marine algae deposited in a saline and reducing environment served as an obvious source rock for the humate. The humate derived from decaying organic remains that descended from the peat into the permeable sand, where it indurated irreversibly over a period shorter than 3500 years.
    AV ČR Brno, Ústav struktury minerálů a hornin
Contributor code
Source format
Import date
    24. 10. 2014