Evolución de rampas carbonatadas aptienses: tectónica sinsedimentaria y eutrofización (Jorrios, Bizkaia)

• Autores: Arantza Aranburu Artano, Miguel Ángel López Horgue, Pedro Angel Fernández Mendiola, Joaquín García Mondéjar
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 3, 2, 2001 (Ejemplar dedicado a: XIV Congreso Nacional de Sedimentología, IV Congreso del Cretácico de España), págs. 139-142
• Idioma: español
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• 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.