Los pares caliza-marga de la Isla de Castro (Coniaciense final-Santoniense inferior, Cuenca Vasco-Cantábrica): variaciones isotópicas (á!80 y á13C) y mineralógicas

Abstract

Analyses carried out on bedded limestone-marl couplets from Castro Island section (latest Coniacian-lower Santonian, Basque-Cantabrian Basin) show clear isotopic (a'780 and al3C) and mineralógica! differences between limestones and marls. Analytical results point out that the sediments suffered a low diagenetic grade, and imply a synsedimentary origin for the limestone-marl couplets. Besides, it is suggested that the deposition of the sediments was influenced by changes in the carbonate production and continental influx strength into the shallow water basin, probably, as a consequence of climatic variations, which could range between wet and dry conditions