Ordovician palynology: balance and future prospects at the beginning of the third millennium.
Ordovician palynologic studies started in the 1930s when Eisenack first described Palaeozoic "hystrichospheres" (later named acritarchs), and defined the chitinozoans and melanosclerites. During the ensuing two decades, Ordovician palynologic investigations were mostly descriptive. It was the rise of the oil industry in the 1950s and 1960s, which accelerated palynologic research, particularly with the recognition that acritarchs and chitinozoans were biostratigraphically important groups for Ordovician stratigraphy. Today, more than 700 publications deal with Ordovician acritarchs, and about 400 papers concern Ordovician chitinozoans. In addition to these two palynomorph groups, other less important organic-walled microorganisms have been studied. These include plant remains (spores, cuticles), scolecodonts and such enigmatic groups as the melanosclerites and the mazuelloids. This paper summarises the research on Ordovician palynomorphs during the 20th century and looks ahead to the types of research that may be important and most fruitful for Ordovician palynology at the beginning of the new millenium. Particular attention is paid to the C.I.M.P./I.G.C.P. no. 410 joint meeting "Ordovician Palynology and Palaeobotany," held in Prague during the 8th International Symposium on the Ordovician System. A brief account is given concerning the global Ordovician chronostratigraphy and the correlation of the main regional series and stages.
Servais
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Laboratoire de Paléontologie, UPRESA 8014 du CNRS, USTL, SN5, F-59655, Villeneuve-d'Ascq-cedex, France
Paris
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