Evolución de rampas carbonatadas aptiensestectónica sinsedimentaria y eutrofización (Jorrios, Bizkaia)
ISSN: 1576-5172
Año de publicación: 2001
Título del ejemplar: XIV Congreso Nacional de Sedimentología, IV Congreso del Cretácico de España
Número: 3
Páginas: 139-142
Tipo: Artículo
Otras publicaciones en: Geotemas (Madrid)
Resumen
The facies and stratigraphic framework analysis of the carbonate ramp systems of the Aptian of Jorrios (Bizkaia, N Spain) indicates a vertical evolution from a homoclinal ramp (Mercadillo) to distally steepened ramp (Juncal ramp). The biotic constituents also differ: oligotrophic lower unit versus eutrophic upper unit. Between both ramps stands a key intermediate glauconitic interval. Its formation reflects low sedimentation rates, rising relative sea-level, hypoxic botton water and reduced oceanic circulation. The vertical change in depositional and faunal style is related to a combination o f factors including: tectonic activity, cold-water masses and environmental eutrophization.