Počet záznamů: 1  

Depositional environments of the Jurassic maghara main coal seam in north central Sinai, Egypt

  1. 1.
    SYSNO ASEP0496698
    Druh ASEPJ - Článek v odborném periodiku
    Zařazení RIVJ - Článek v odborném periodiku
    Poddruh JČlánek ve WOS
    NázevDepositional environments of the Jurassic maghara main coal seam in north central Sinai, Egypt
    Tvůrce(i) Edress, N.A.A. (EG)
    Opluštil, S. (CZ)
    Sýkorová, Ivana (USMH-B) RID, ORCID
    Zdroj.dok.Journal of African Earth Sciences. - : Elsevier - ISSN 1464-343X
    Roč. 140, APR (2018), s. 241-255
    Poč.str.15 s.
    Forma vydáníTištěná - P
    Jazyk dok.eng - angličtina
    Země vyd.GB - Velká Británie
    Klíč. slovaMaghara main coal ; Lithotypes ; macerals ; Jurassic ; Egypt
    Vědní obor RIVDB - Geologie a mineralogie
    Obor OECDGeology
    Způsob publikováníOmezený přístup
    Institucionální podporaUSMH-B - RVO:67985891
    UT WOS000427999500017
    EID SCOPUS85044631045
    DOI10.1016/j.jafrearsci.2018.01.017
    AnotaceTwenty-eight channel samples with a cumulative thickness of about 4 m collected from three sections of the Maghara main coal seam in the middle Jurassic Safa Formation have been studied for their lithotype and maceral compositions to reconstruct the character of peat swamp, its hydrological regime and the predominating type of vegetation. Lithotype composition is a combination of dully lithotypes with duroclarain (19% of total cumulative thickness), clarodurain (15%), black durain (15%), and shaly coal (15%) and bright lithotypes represented by clarain (23%), vitrain (12%) and a small proportion of wild fire-generated fusain (1%). Maceral analyses revealed the dominance of vitrinite (70.6% on average), followed by liptinite (25.2%) and inertinite (8.1%). Mineral matter content is ∼9% on average and consists of clay, quartz and pyrite concentrate mostly at the base and the roof of the seam. Dominantly vitrinite composition of coal and extremely low fire- and oxidation-borne inertinite content, together with high Gelification Indices imply predomination of waterlogged anoxic conditions in the precursing mire with water tables mostly above the peat surface throughout most of the time during peat swamp formation. Increases in collotelinite contents and Tissue Preservation Index up the section, followed by a reversal trend in upper third of the coal section, further accompanied by a reversal trend in collodetrinite, liptodetrinite, alginite, sporinite and clay contents records a transition from dominately limnotelmatic and limnic at the lower part to dominately limnotelmatic with increase telmatic condition achieved in the middle part of coal. At the upper part of coal seam an opposite trend marks the return to limnic and limnotelmatic conditions in the final phases of peat swamp history and its subsequent inundation. The proportion of arborescent (mostly coniferous) and herbaceous vegetation varied throughout the section of the coal with tendency of increasing density of arborescent vegetation to the middle part of the coal seam section. The intercalation of coal in shallow marine strata implies that peat swamp precursor formed in a coastal setting, probably on delta plain or lagoon. Its formation was controlled by water table changes driven by sea level fluctuations that created an accommodation space necessary for preservation of peat.
    PracovištěÚstav struktury a mechaniky hornin
    KontaktIva Švihálková, svihalkova@irsm.cas.cz, Tel.: 266 009 216
    Rok sběru2019
Počet záznamů: 1  

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