|Ostracods and lithofacies of the Middle/Upper Devonian boundary stratotype (Puech de la Suque, Montagne Noire, France)|Casier, J.-G.; Préat, A.R. (2007). Ostracods and lithofacies of the Middle/Upper Devonian boundary stratotype (Puech de la Suque, Montagne Noire, France). Bull. Soc. Géol. Fr. 178(4): 293-304. dx.doi.org/10.2113/gssgfbull.178.4.293
In: Bulletin de la Société Géologique de France. Société Géologique de France: Paris. ISSN 0037-9409, more
ostracods; microfacies; Givetian; Frasnian; GSSP; Montagne Noire
This paper discusses ostracods and their environmental setting close to the Givetian/Frasnian boundary in the Puech de la Suque Global Stratotype Section and Point. The ostracod fauna belongs exclusively to the Eifelian mega-assemblage and is largely dominated by Podocopina instars. Consequently, the majority of the 33 species recognised and illustrated is described in open nomenclature. The abundance of instars also indicates that most of beds are related to storm deposition. The composition of the fauna suggests a regression in the late Givetian followed by a transgression at the beginning of the Frasnian. Only one ostracod assemblage collected in the upper part of the section indicates a deeper setting below the storm wave base. Eight taxa disappeared in two steps near the Givetian/Frasnian boundary, probably in relation to the Frasnes Event.
The sedimentological analysis confirms that the section is constituted principally of storm deposits and reveals in addition the presence of numerous reddish hardgrounds highlighting an important condensation of the sequence.