J. Elez

A GIS-based methodology to quantitatively define an Adjacent Protected Area in a shallow karst cavity: the case of Altamira cave.

Different types of land use are usually present in the areas adjacent to many shallow karst cavities. Over time, the increasing amount of potentially harmful matter and energy, of mainly anthropic origin or influence, that reaches the interior of a shallow karst cavity can modify the hypogeal ecosystem and increase the risk of damage to the Palaeolithic rock art often preserved within the cavity. This study proposes a new Protected Area status based on the geological processes that control these matter and energy fluxes into the Altamira cave karst system. Analysis of the geological characteristics of the shallow karst system shows that direct and lateral infiltration, internal water circulation, ventilation, gas exchange and transmission of vibrations are the processes that control these matter and energy fluxes into the cave. This study applies a comprehensive methodological approach based on Geographic Information Systems (GIS) to establish the area of influence of each transfer process. The stratigraphic and structural characteristics of the interior of the cave were determined using 3D Laser Scanning topography combined with classical field work, data gathering, cartography and a porosity-permeability analysis of host rock samples. As a result, it was possible to determine the hydrogeological behavior of the cave. In addition, by mapping and modeling the surface parameters it was possible to identify the main features restricting hydrological behavior and hence direct and lateral infiltration into the cave. These surface parameters included the shape of the drainage network and a geomorphological and structural characterization via digital terrain models. Geological and geomorphological maps and models integrated into the GIS environment defined the areas involved in gas exchange and ventilation processes. Likewise, areas that could potentially transmit vibrations directly into the cave were identified. This study shows that it is possible to define a Protected Area by quantifying the area of influence related to each transfer process. The combined maximum area of influence of all the processes will result in the new Protected Area. This area will thus encompass all the processes that account for most of the matter and energy carried into the cave and will fulfill the criteria used to define the Protected Area. This methodology is based on the spatial quantification of processes and entities of geological origin and can therefore be applied to any shallow karst system that requires protection.

The deterioration of Circular Mausoleum, Roman Necropolis of Carmona, Spain

The Circular Mausoleum tomb in the Roman Necropolis of Carmona was carved on a calcarenite sequence in an ancient quarry located in the town of Carmona, Southern Spain. This rock-cut tomb, representative of Roman burial practices, currently suffers from serious deterioration. A detailed survey over several years permitted the identification of the main tombs pathologies and damaging processes, which include loss of material (scaling, flaking, granular disintegration), surface modifications (efflorescences, crusts and deposits) and extensive biological colonization. The results obtained in this study indicated that anthropogenic changes were largely responsible and enhanced the main alteration mechanisms observed in the Circular Mausoleum. Based on the deterioration diagnosis, effective corrective actions were proposed. This study shows that any conservative intervention in the interior of the tomb should be preceded by accurate in situ measurements and laboratory analyses to ascribe the source of the deterioration damages and thus designing effective treatments.

The Karstic Habitat of Spelaeogriphaceans from the Las Hoyas Fossil Site (Upper Barremian, Serranía de Cuenca, Spain)

Fossil remains of spelaeogriphaceans (Family Acadiocarididae) are common in Las Hoyas Konservat-Lagerstatte (upper Barremian, La Huerguina Formation, southwestern Iberian Basin), although they belong to an extremely rare group in the fossil record. They have been interpreted as having inhabited karstic environments as do their contemporaneous equivalents; however, this interpretation has not been clearly proven. Based on tectonic, sedimentological, geochemical, and palaeontological data, the aim of this work is to explore the evidence for active karst processes contemporaneous with Barremian sedimentation in order to support the palaeoecological hypothesis, and to shed further light on the reconstruction of the palaeogeographical evolution of the basin.

The Stratigraphy and Rifting Evolution of the Oxfordian–Barremian (Upper Jurassic–Lower Cretaceous) in the Serranía de Cuenca (Southwestern Iberian Ranges, Spain)

The Oxfordian to late Barremian geological history of the Serrania de Cuenca Basin is very different from that of other domains of the Iberian Basin. A rifting-related phase of thermal uplift of the area prompted the emersion of the Jurassic marine platforms during the Oxfordian. For almost 30 Myr, the Jurassic carbonates were covered by thick tropical soils and preserved from true erosion. The onset of extension in this area initiated karst processes and progressively generated small and complex half-graben-like basins that were filled by a continental subtropical system of wetlands (the La Huerguina Formation). This unit shows a complex internal architecture that has been separated into six different stratigraphic units, some of them defined for the first time.

Palaeoenvironmental Interpretation of Palaeosols and Palustrine Carbonates of the Earliest Cretaceous Terrestrial Ecosystems in the Serranía de Cuenca, Iberian Ranges, Spain

Bauxitic materials redeposited on top of the karstified Jurassic carbonates in the Serrania de Cuenca, Iberian Ranges, display palaeosols and palustrine carbonates that were deposited coevally with the sedimentation of the Rambla de las Cruces I Sequence (upper Barremian; La Huerguina Formation). This sequence contains rich micro- and macrovertebrate assemblages in the Buenache and Las Hoyas basins, to the south of the study area. Different palaeodrainage and palaeotopographic locations are responsible for the different types of palaeosols, some of which preserve vertebrate remains. This study clarifies various palaeoenvironmental aspects of the sedimentation of the La Huerguina Formation, and evaluates upper Barremian terrestrial settings as potential fossil sites.