Hydrothermal Dolomite Reservoir Analogue Study - the Cantabrian Case Study

In the platform to slope Cretaceous carbonate succession of the Cantabrian Mountains (N-Spain), sub-seismic fault restricted dolomite bodies predominate while in the platform interior, massive stratabound bodies, several square kilometre in size, occur. The latter have been studied in the field, by petrography (cathodoluminescence, flourescence petrography, SEM and computed tomography), geochemistry (trace element as well as stable C- and O-isotopes, Sr-isotopes), microthermometry of fluid inclusions and petrophysically (porosity – permeability). All over the area, ferroan dolomites precede non-ferroan dolomites. More in detail matrix dolomites, coarse crystalline dolomites and zebra dolomites can be recognised. In the platform to edge setting these dolomites are dominantly non-porous while extended dolomite bodies with reservoir properties occur in the platform interior.