| one publication added to basket [8785] | Stratigraphical implications of the relationships between ammonites and facies: examples taken from the Lower Cretaceous (Valanginian - Hauterivian) of the western Tethys
Bulot, L.G. (1993). Stratigraphical implications of the relationships between ammonites and facies: examples taken from the Lower Cretaceous (Valanginian - Hauterivian) of the western Tethys, in: House, M.R. (Ed.) The Ammonoidea: environment, ecology, and evolutionary change. pp. 243-265
In: House, M.R. (Ed.) (1993). The Ammonoidea: Environment, ecology, and evolutionary change. The Systematics Association Special Volume, 47. Clarendon Press: Oxford. ISBN 0-19-857765-6. 353 pp., more
In: The Systematics Association Special Volume, more
|
| Abstract |
Recent studies on the Valanginian and Hauterivian of western Tethys provide good evidence of ammonite distribution linked to facies. Among the Ammonitina, the Olcostephaninae and Neocomitidae give the best examples of faunal assemblage variations between basin and outer shelf. During most of the Valanginian, Olcostephanus was split into two different 'lineages': O. (0.) guebhardi (Kilian) and related species are restricted to the outer shelf facies, while O. (0.) tenuituberculatus Bulot and its descendants correspond to the basin facies. A similar distribution applies to phylloceratids, lytoceratids, haploceratids and to the many neocomitids, such as Neocomites, Dicostella, Acanthodiscus, Leopoldia, Saynella, and Lyticoceras. Even boreal dichotomitids are affected by this facies segregation. Obviously those distributions imply problems for platform-basin correlations and the need to individualize local biostratigraphical units. Nevertheless, from time to time, 'mixed basin-platform assemblages' occur. Those Horizons of Faunal Uniformity (HUF) correspond to periods of faunal turnover and exchange, correlate with sea-level changes and indicate maximum flooding surface. |
|
