Evaluación de los efectos diagenéticos en la relación 87Sr/86Sr en conchas de rudistas y Chondrodonta sp. de las calizas rojas del Aptiense – Albiense inferior de Ereño (Bizkaia)

Abstract

87Sr/86Sr isotopic ratios measured on rudist and Chondrodonta sp. shells from upper Aptian – lower Albian red limestones of Ereño (Bizkaia) reveal different degrees of diagenetic alteration when compared to coeval values. Chondrodonta sp. and requienid shells show a better degree of chemical preservation, whereas caprotinid and monopleurid shells seem to be more affected by diagenetic fluids. The same conclusion can be obtained when 87Sr/86Sr values are plotted against cationic contents in Sr, Na, Mg, Fe and Mn