Mineralogía, geoquímica y evolución diagenética de los materiales carbonatados del área de Mérida (Badajoz)

Abstract

The carbonate rocks of the Mérida area (SW Spain) belong to an Early Cambrian Formation consisting, in its lower part, of fine-grained carbonaceous limestones with abundant interbedded layers and nodules of chert, whereas the upper part of this Formation is largely dolomitic. The chemical and mineralogical composition of the limestones is relatively homogeneous. Instead, the dolomitic rocks have been grouped in three main types (fine-grained dark dolostones; banded whitish dolostones; and cavernous brownish dolostones) which show distinctive petrographical and geochemical features. Sr/Fe and Sr/Mn ratio s have been used to quantify the degree of dolomitization. The obtained values have allowed to recognize a geochemical trend consistent with a genetic model based on dolomitization by late diagenetic processes.