Contexto geológico y características petrofísicas de las rocas carbonáticas del Cerro de la Rosa (Toledo)

Resum

Investigation on building stones used in the Toledo Cathedral (Central Spain) resulted in the recognition of the sedimentary formations that supplied dolostones during the earlier works in the Cathedral (XIII to XV centuries). Such formations are located in the Cerro de la Rosa, an area close to Toledo where the finding of remains of marine fauna at the beginning of the present century lead to scientific controversy. Main controversy dealt with the chronological attribution of the fossil fauna (Cretaceous, Oligocene, or lower Miocene, after different authors) and subsequent paleogeographical implications for the geology of the Tajo Basin and adjacent areas. This study concludes that the Cerro de la Rosa outcrop is made up of marine faune bearing-carbonate and terrigenous deposits of late Cretaceous age overlain unconformably by early Paleogene continental sediments. This basic stratigraphic. framework is relevant as it allows to solve the aforementioned geological controversy. Petrographic and petrophysic testing of the Cerro de la Rosa dolostones leads to the distinction of three main dolostone types (homogeneous, sandy, and nodular dolostones), the three types showing different behaviour in terms of absorption, capilarity, desorption, durability, etc. Higher weathering rates are determined in both sandy and nodular dolostones, this being controlled by higher porometry and water accesibility to the pore network. Results obtained from petrophysical testing in laboratory fit well with observations on weathering degree of the dolostones in the Toledo Cathedral.