S. Ordóñez

Pore size distribution and the durability of a porous limestone

Abstract A comparison of durability estimations based on mercury porosimeter data and experimental salt crystallization tests carried out on Bateig Stone from Alicante, Spain, establish that the main factor in the salt crystallization durability test is the ‘ink bottle’ pore system, identified by the presence of residual mercury in large pores after porosity testing. In addition, the results suggest that the commonly used indirect durability tests may not be considered a scientific definition of building stone behaviour.

Hydration diapirism: a climate-related initiation of evaporite mounds in two continental Neogene basins of central Spain

Abstract While many halokinetic models consider that a thick overburden is necessary before diapirism develops, other studies show that salt might begin to move soon after deposition in response to different factors (e.g. regional extension). We describe two continental Neogene basins in central Spain, characterized by three Miocene sedimentary units, where unusually early initiation of evaporite mounds or ‘incipient pillows’ occurs, with no overburden on top of them. The arguments suggesting the early bulging of the evaporites of the Lower Unit, forming a palaeorelief before and during the deposition of the Intermediate Unit, rely on certain characteristics of the palaeokarsts developed on the roof of the Lower Unit, as well as in the nature, disposition, thickness, and synsedimentary processes of the Intermediate Unit. Folds, faults, tension gashes, and collapse structures develop within the evaporite mounds, and these deformation features might be related to their uplift history. The agent of initiation suggested in this paper for the evaporite mounds ‘hydration diapirism’, or a volume increase related to the hydration of anhydrite to gypsum has not been previously recognized in the literature. A series of sedimentological and palaeontological arguments further suggest that this chemical reaction was triggered by a climatic change at the boundary between the Lower and the Intermediate Units.

DEGRADATION OF BUILDING MATERIALS OF THE TOLEDO CATHEDRAL (SPAIN)

The Toledo Cathedral was built with different types of stones (mainly granites and carbonates) which display varied weathering features. It is concluded that rock degradation induced by pollution is weak. The alteration has been mainly due to climatic controlled factors, such as humidity, thermal changes and frosting. These processes resulted in scaling of the stone blocks, alteration of the granite texture to sand, and the development of discontinuities within the rocks.