GSSP for the Ludlow Pridolí Boundary


Definition:

The base of the Pridoli Series is defined in the Požáry Section of the Daleje Valley, Prague, Czech Republic. The basal limit of the Přídoli Series is defined within Bed 96 in the section coincident with the first occurrence of the graptolite species Monograptus parultimus
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Location:

The Požáry Section is located on the southern slope of the Daleje Valley, about 1.5km east of Reporyje near the south-western boundary of Prague, in an abandoned railway cut at the entrance to the Požáry Quarries.
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Sedimentology:

The section is characterized by monoclinal south-westerly dipping rocks. The "cephalopod bank" of coarse biodetrital limestone with common cepahalopods is developed at the top of the underlying Kopanina Formation. The base of the Pozáry Formation is characterized mostly by unsorted, bioclast-supported and micrite-supported biodetrital and biomicritic limestones with some intercalations of calcareous shale, and sorted clast-supported biodetrital limestone. Higher, above the base of the Přídoli Series, the sequence is formed of platy limestones with intercalations of calcareous shale.
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Primary Markers:

First occurrence of the graptolite species Monograptus parultimus within bed 96.



Secondary Markers:

Conodonts:
The last occurrence of Ozarkodina crispa is just below the Ludlow-Pridoli Boundary.

Chitinozoans:
The first occurrence of Urnochitina gr. urna is just above the Ludlow-Pridoli boundary in bed 97 of the Požáry Section.

References:

Kríz, J., 1989. The Přídoli Series in the Prague Basin (Barrandium area, Bohemia). In: Holland, C. H. and Bassett, M. G. (eds.). A global standard for the Silurian System. National Museum of Wales, Geological Series 9, p. 90 - 100, Cardiff.