Record details

    Late Devonian (Famennian) Glaciation in South America and Marine Offlap on other Continents
Statement of responsibility
    Peter E. Isaacson, Jindřich Hladil, Shen Jian-Wei, Jiří Kalvoda, George Grader
Other titles
    North Gondwana: Mid-Palaeozoic Terranes, Stratigraphy and Biota. (Variant.)
    Spätdevonische (Famennium) Vereisung in Südamerika und marine Regression in anderen Kontinenten
    Grader, George
    Hladil, Jindřich, 1953-
    Isaacson, Peter E.
    Jian-Wei, Shen
    Kalvoda, Jiří
Source title - serial
    Abhandlungen der Geologischen Bundesanstalt
    Vol. 54
    p. 239-257
    9 obr., 2 tab., 4 s.bibl.
    Německé resumé
    Zkr. název ser.: Abh. Geol. Bundesanst. (Wien)
Subject group
    glaciály předkvartérní
    moravskoslezské prevariské paleozoikum
    sedimenty karbonátové
    zóny biostratigrafické
Geographical name
    Amerika severní
    Čína jižní
Abstract (in english)
   Given the new Phanerozoic timescale of Gradstein & Ogg (1996). Famennian events present a more significant in Late Devonian time. The Devonian glaciation event occurred over a broad area, including much of Brazil (Parnaíba, Amazonas, and Solimöes basins) and Bolivia (Madre de Dios and Atliplano areas of the paleozoic foreland basin), and this initial glaciation continued into earliest Carboniferous (Tournaisian) time. It is dated within at least the LE, LN and VI palynozones. Bolivian glaciation events include unbedded and poorly bedded diamictites with striated and faceted clasts sedimentary and granitic rocks sourced from the adjacent foreland fold- and thrust-belt. Some evidence suggests that at least two major ice advances occurred within Devonian time.
   Coeval with the Gondwana glacial event is a geologic record in North America, central Europe and southern China that suggests a very rapid sea-level fall that exhumed and eroded carbonate platforms, deposited siliciclastics, and generated lacunae in the Famennian record. The lowstand resulted in extensive carbonate breccias, shoal-deposits and evaporites in western U.S.A. and Canada. Widespread early Famennian and older carbonate breccias located in Idaho and western Montana may manifest coeval subaerial edposure and interaction with a fluctuating phreatic weathering zone related to varying sea-levels. Possible similar breccias occur also in Nevada. Lowstand clastic-wedges were deposited in a major forced regression in black shales (eastern U.S.A.). The glaciation was apparently responsible for lacunae in the Famennian rock-record in many places.
   In Moravia, Famennian physil and siliciclastic influx increased as a result of weathering in newly-emergent highs that resulted from sea-level drop. Partial sea level drops were manifested by ferruginous oolites, which developed in nearshore environments and were subsequently dispersed onto adjacent slopes by storm resedimentation. In southern China, aggradation, siliciclastic influx, dolomitization from evaporation, aggradation, siliciclastic influx, dolomitization from evaporation, and shallow-water carbonates resulted from Famennian sea-level lowering. The coupling of glacial and lowstand events explains the sudden appearance of shallow-marine, as well as subaerially-affected features within a generally transgressive sea that breached the North American craton during Late Devonian (Frasnian) time
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    31. 3. 2008
Import date
    8. 8. 2012