Cenomanian (early Late Cretaceous) Ammonoid Faunas of Western Europe. Part I: Biochronology (Unitary Associations) and Diachronism of Datums.

摘要: Biochronological data of Cenomanian ammonoid faunas Western Europe are analyzed for three well-documented basins: the Vocontian Basin in southeastern France, Mnster Germany, and Anglo-Paris Basin. A taxonomically standardized set is constructed these basins includes more than one hundred species with deterministic Unitary Association Method. Data each basin first processed separately, thus yielding regional biochronological zonations. Then, sequences together as a three- section construction inter-basin sequence. The latter comprises 24 unitary associations grouped eight zones Stage. These results take into account that co-occur time space (real coexistence), those only (virtual do not nor (exclusion chronological significance). At paleogeographical scale Europe, this new zonation good agreement widely used standard zonation, but its resolution times higher. This demonstrates benefits applying Method, even to taxonomic group which traditionally acknowledged leading dating Mesozoic marine rocks. It also highlights variable completeness faunal record through time, reveals substantial number taxa (47%, inclusive some indexes) have diachronous distribution across basins. However, such an enhanced resolution, no preferred orientation emerges, suggesting none seemed functioned paleobiogeographical source or sink. absence any direction diachronism datums most likely explained by two, non-mutually exclusive causes: either random incompleteness and/or common history