Evolución de rampas carbonatadas aptiensestectónica sinsedimentaria y eutrofización (Jorrios, Bizkaia)

  1. A. Aramburu
  2. M.A. López Horgue
  3. P.A. Fernández-Mendiola
  4. J. García-Mondéjar
Revista:
Geotemas (Madrid)

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.