Abrasion surfaces on internal moulds of ammonites as palaeobathymetric indicators

Some abrasion surfaces displayed by internal moulds of ammonites, such as annular abrasion furrows formed on the venter surface and ellipsoidal abrasion facets preferentially developed on the last third part of the preserved whorl, are diagnostic criteria of taphonomic reworking. These taphonomic cr...

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Detalles Bibliográficos
Autores: Fernández López, Sixto Rafael, Meléndez Hevia, Guillermo
Tipo de recurso: artículo
Fecha de publicación:1994
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/58486
Acceso en línea:https://hdl.handle.net/20.500.14352/58486
Access Level:acceso abierto
Palabra clave:564.53(234.1)
Taphonomy
Ammonites
Iberian Range
Paleontología
2416 Paleontología
Descripción
Sumario:Some abrasion surfaces displayed by internal moulds of ammonites, such as annular abrasion furrows formed on the venter surface and ellipsoidal abrasion facets preferentially developed on the last third part of the preserved whorl, are diagnostic criteria of taphonomic reworking. These taphonomic criteria indicate that the internal moulds have been exhumed and moved before their final burial. We explain the origin of these abrasion surfaces by the action of directional (non oscillatory) currents in very shallow water, most probably in intertidal environments. The distribution of ammonite moulds displaying such preservational features is correlated with the changes in the facies and the trend of the sedimentary sequences. Taphonomic analysis of Jurassic ammonites of the Iberian Range underlines the importance and usefulness of taphonomic gradients in sequence stratigraphy and palaeogeographic reconstructions.