Record details

Title
    Plant megafossils in Devonian stratigraphy: a progress report
Statement of responsibility
    Dianne Edwards, Muriel Fairon-Demaret, Christopher M. Berry
Other titles
    Subcommission on Devonian Stratigraphy - Fossil groups important for boundary definition (Variant.)
Author
    Berry, Christopher M.
    Edwards, Dianne
    Fairon-Demaret, Muriel
Language
    anglicky
Source title - serial
    Courier Forschungsinstitut Senckenberg
Vol./nr.
    Roč. 220
Pages
    s. 25-37
Year
    2000
Notes
    2 obr., 5 s.bibl.
    il.
    Zkr. název ser.: Cour. Forsch.-Inst. Senckenberg
Subject group
    biostratigrafie
    devon
    megaspory
    paleogeografie
    Plantae
Geographical name
    Svět
Keyword
    Devonian
    Megafossils
    Plant
    Progress
    Report
    Stratigraphy
Abstract (in english)
   Constraints on the uses of plant megafossils in stratigraphy imposed by imprecise dating, questinable identifications and shortage of global occurrences are discussed, although the first has to some extent been overcome by more detailed palynological dating schemes. Banks phytozonation scheme for the Devonian, in which six zones (II-VII incl.) are distinguished, is revised in the light of new evidence. Particular attention has been paid to the behaviour of taxa at established stratigraphic boundaries. In two cases, Banks division remain coincident with stage boundaries (IV/V = Eifelian/Givetian; V/VI=Givetian/Frasnian). His oldest Devonian zone (II=Zosterophyllum Zone) originally began at the Silurian-Devonian boundary, but based on Australian evidence, probably extends into the Silurian (Ludlow). It is here also subdivided near the top, marking a major diversification of zosterophylls.
   The base of Banks Zone III (Psilophyton) is now considered coincident with the Lochkovian/Pragian boundary. Increased diversity near the Pragian-Emsian boundary, the most difficult one to correlate palynologically, suggests further subdivision of the Psilophyton Zone. Banks Zones IV and V (Hyenia and Svalbardia) remain unchanged, except that uncertainties relating to the validity of the genus Hyenia result in substitution of "Cladoxyls" for the nominal taxon for Zone IV. Subdivision of Banks final zone (VII-Rhacophyton) is related to the appearance of well substantiated Cyclostigma at the base of the "Srunian", the zone itself being extened to just above the Frasnian-Famennian boundary. A brief phytogeographic overview suggests that provincialism detected in Early and Mid Devonian times becomes less obvious in the latest Devonian, a conclusion broadly confirmed by palynological studies
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    14. 8. 2007
Import date
    8. 8. 2012