Record details

Title
    Cementation and blackening of Holocene sands by peat-derived humates: A case study from the Great Dune of Pilat, Landes des Gascogne, Southwestern France
Author
    Havelcová, Martina
    Machovič, Vladimír
    Suchý, V.
    Sýkorová, Ivana
    Trejtnarová, Hana
    Zeman, Antonín
Language
    anglicky
Publication type
    článek v odborném periodiku
Source title - serial
    International Journal of Coal Geology
Vol./nr.
    Roč. 114, JUL
Pages
    s. 19-32
Year
    2013
Notes
    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
    cementation
    humate
    peat
Keyword
    Blackening
    Case
    Cementation
    Dune
    France
    Gascogne
    Great
    Holocene
    Humates
    Landes
    Peat-derived
    Pilat
    Sands
    Southwestern
    Study
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.
Contributor
    AV ČR Brno, Ústav struktury minerálů a hornin
Contributor code
    AV ČR, ÚSMH
Source format
    U
Import date
    24. 10. 2014