Geoquímica de los materiales Pelíticos Cámbricos al Noroeste de Zafra (Badajoz)

Abstract

Cambrian formations from NW of Zafra are composed of pelitic sequences distributed along the Lower Cambrian (LC) up to the Middle-Upper Cambrian (MUC). These sedimentary sequences have a more sandstone component in LC with respect to MUC. Chemical characteristics of LC and MUC pelites present some differences, w ith hig her A l20 3 co ntents and lo w e r S i 0 2 in the M U C pelites. N o rm a liza tio n w it h respect to PAAS shows the sim ila rities b e tw ee n Cambrian pelites and this n o rm a liza tio n value. Nevertheless, Cambrian pelites are characterized by lower CaO and Sr contents than PAAS. Major and trace element absolute values and ratios (Zr/Ni, Zr/Co, etc.) allow us to propose a mainly felslc source area for this Cambrian sequence in contrast to the more mafic source area for Precambrian pelites outcropping at this region