|Corrélation de successions de l'Albien par les ammonites entre la Province Nord-Pacifique et les Provinces européenne et arctique du Domaine boréal: zonation, eustatisme et paléobiogéographie|Amédro, F.; Robaszynski, F. (2005). Corrélation de successions de l'Albien par les ammonites entre la Province Nord-Pacifique et les Provinces européenne et arctique du Domaine boréal: zonation, eustatisme et paléobiogéographie. Géobios 38(5): 585-607. dx.doi.org/10.1016/j.geobios.2004.04.004
In: Géobios. Association Européenne de Paléontologie: Lyon. ISSN 0016-6995, more
Albian; Northern California; ammonite zones; faunal provinces; globalcorrelations; palaeobiogeography
|Authors|| || Top |
- Amédro, F.
- Robaszynski, F.
The vertical distribution of Albian ammonites of the North Pacific Province is described on the basis of several sections located in Northern California. Nine Albian ammonite assemblages are identified, compared to the 4 previously described by Murphy in 1956. Owing to several caps of observation possibly more assemblages could exist. In the North California Albian history, the first results show a Succession of confinement periods - with numerous endemic faunas - followed by periods of open communications with other faunal provinces. As ail example, the base of the Middle Albian is marked by exotic ammonites coming from the Tethyan realm (Oxytropidoceras, Lyelliceras) and front the Arctic Province of the Boreal realm (Gastroplites, Pseudopulchellia). These ammonites - except Oxytropidoceras - were not known in that area and are described relatively to their palacobiogeographical interest. Although rare these migrant faunas give valuable elements to correlate these various provinces. Planktonic foraminifera confirm the existence of open sea communications during the uppermost Albian.
With such faunal links, a comparison is proposed between the Albian ammonite zonation of Northern California and the standard and phyletic ones of Europe. This attempt suggests that the major connections between the three faunal provinces are established at second order peak transgressions in the Early and Middle Albian, and during the sea-level high of the Late Albian transgressive period. So, it seems that the vertical distribution of Albian non-endemic ammonites of North California and Europe is largely controlled by global eustatic events. Two palaeobiogeographic maps for Early and Middle Albian and one map for the late Late Albian show the migration outer of these exotic ammonites.