Reference : Biochemostratigraphy of the upper Frasnian in the Namur–Dinant Basin, Belgium: Implic...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Earth sciences & physical geography
Biochemostratigraphy of the upper Frasnian in the Namur–Dinant Basin, Belgium: Implications for a global Frasnian–Famennian pre-event
Azmy, Karem [ > > ]
Poty, Edouard [ > > ]
Mottequin, Bernard mailto [Université de Liège - ULiège > Département de géologie > Paléontologie animale et humaine >]
Palaeogeography, Palaeoclimatology, Palaeoecology
Elsevier Science
Yes (verified by ORBi)
The Netherlands
[en] Chemostratigraphy ; Late Frasnian ; Namur-Dinant Basin ; Belgium ; brachiopods
[en] The Upper Frasnian sequence of the Namur–Dinant Basin in southern Belgium consists of mixed siliclastic–carbonate succession of a ramp setting, where the sequence spans the rhenana–linguiformis conodont zones. Earlier studies investigated the chemostratigraphic variations during the Frasnian-Famennian event, but little has been yet known about the nature of the counterpart variations that immediately preceded that time interval. Despite the scarcity of well-preserved brachiopods, sixty–one calcitic shells were collected mainly from beds of the Neuville and Les Valisettes formations (Lower and Upper rhenana zones), to investigate biochemostratigraphic profiles of oxygen-, carbon-isotope and rare earth element (REE) variations of the time interval immediately before the Frasnian-Famennian boundary. The δ18O and δ13 C values of the well-preserved shells range from − 9.5 to − 5.6 ‰ VPDB (− 7.7 ± 1.1, n = 33) and from − 1.8 to 3.8 ‰ VPDB (1.1 ± 1.7, n = 33), respectively, which are within the documented global values. The C- and O-isotope profiles exhibit parallel shifts, particularly at the top of the Neuville Formation (top of the Lower rhenana Zone), which are associated with a sea-level rise and shrinkage in the brachiopod community. Also, the Th/U (0.9 ± 0.6, n = 16) and Ce/Ce* (2.2 ± 0.5, n = 16) ratios suggest deposition under reducing conditions consistent with sea transgression.
C- and O-isotopic composition of Middle Devonian biogenic low-Mg calcite ► A global Frasnian-Famennian pre-event ► REE composition of Upper Frasnian brachiopods

File(s) associated to this reference

Fulltext file(s):

Restricted access
Azmy, Poty & Mottequin (2012).pdfPublisher postprint1.03 MBRequest copy

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.