Morphométrie de nannofossiles calcaires au passage Crétacé-Paléocène des coupes de Bidart (France) et d'Elles (Tunisie). Comparaison avec les isotopes stables du carbone et de l'oxygène

TY - JOUR

T1 - Morphométrie de nannofossiles calcaires au passage Crétacé-Paléocène des coupes de Bidart (France) et d'Elles (Tunisie). Comparaison avec les isotopes stables du carbone et de l'oxygène

AU - Thibault, Nicolas

AU - Minoletti, Fabrice

AU - Gardin, Silvia

AU - Renard, Maurice

PY - 2004/12/1

Y1 - 2004/12/1

N2 - A detailed biometric analysis of five species of calcareous nannofossils was carried out on samples from the uppermost Maastrichtian and lowermost Danian of Bidart (Basque Country, SW France) and Elles (central Tunisia). This study reveals the existence of two morphotypes of A. cymbiformis and an abrupt reduction of the five species immediately below the K-T boundary, likely in relation with a stressful environment, which would have developed just before the deposition of the iridium level, followed by a sudden size increase in the basal Danian reflecting the reworking pattern of the Cretaceous species. In addition, the comparison of biometric and isotopic data seems to indicate that the two morphotypes of A. cymbiformis have different ecologies, the large one being favoured in cool waters.

AB - A detailed biometric analysis of five species of calcareous nannofossils was carried out on samples from the uppermost Maastrichtian and lowermost Danian of Bidart (Basque Country, SW France) and Elles (central Tunisia). This study reveals the existence of two morphotypes of A. cymbiformis and an abrupt reduction of the five species immediately below the K-T boundary, likely in relation with a stressful environment, which would have developed just before the deposition of the iridium level, followed by a sudden size increase in the basal Danian reflecting the reworking pattern of the Cretaceous species. In addition, the comparison of biometric and isotopic data seems to indicate that the two morphotypes of A. cymbiformis have different ecologies, the large one being favoured in cool waters.

KW - Calcareous nannofossils

KW - K-T boundary

KW - Morphometry

KW - Morphotypes

KW - Stable isotopes

UR - http://www.scopus.com/inward/record.url?scp=12544258726&partnerID=8YFLogxK

U2 - 10.2113/175.4.399

DO - 10.2113/175.4.399

M3 - Tidsskriftartikel

AN - SCOPUS:12544258726

SN - 0037-9409

VL - 175

SP - 399

EP - 412

JO - BSGF - Earth Sciences Bulletin

JF - BSGF - Earth Sciences Bulletin

IS - 4

ER -