Calcareous nannofossil quantitative and biostratigraphic analyses integrated with carbon and oxygen stable isotopes were carried out on the core ANDRA (Agence Nationale pour la gestion des Dechets Radio-Actifs-FRANCE) HTM 102 across the Callovian/ Oxfordian boundary drilled at Cirfontaines-en-Omois, Department de Haute-Marne, eastern France, Calcareous nannofossil assemblages at the Callovian-Oxfordian transition are dominated by the genus Watznaueria. An increase in abundance of Biscutum spp. and A-group, which consists of Axopodorhabdus spp. (A. atavus, A. rahla, and A. cylindratus), Podorhabdus grassei, Octopodorhabdus decussatus, Hexapodorhabdus cuvillieri (family Axopodorhabdaceae), and Triscutum spp., correlates with a significant positive excursion in delta O-18 suggesting that these groups were probably adapted to cooler surface waters. A positive increase in delta C-13 values is coupled with high abundances of eutrophic taxa such as Zeughrabdontus erectus, Biscutum spp., and small-sized Watznaueria britannica, and a decrease in abundance of the big and oligotrophic taxa Schizosphaerella punctulata and Watznaueria manivitae. Climate cooling across the Callovian/Oxfordian boundary probably triggered a breakdown in stratification of surface waters leading to more intense nutrient recycling and higher primary productivity that favoured the shift in abundance of small-sized eutrophic taxa in the East Paris Basin. (c) 2006 Elsevier B.V. All rights reserved.
|Titolo:||Calcareous nannofossil changes during the late Callovian-early Oxfordian cooling phase|
|Autori interni:||ERBA, ELISABETTA (Secondo)|
|Parole Chiave:||Callovian-Oxfordian transition; calcareous nannofossils; climatic changes; primary productivity|
|Settore Scientifico Disciplinare:||Settore GEO/01 - Paleontologia e Paleoecologia|
|Data di pubblicazione:||2006|
|Digital Object Identifier (DOI):||10.1016/j.marmicro.2006.02.007|
|Appare nelle tipologie:||01 - Articolo su periodico|