Análisis de los yacimientos de icnitas de dinosaurios de La Rioja (N de España) como recurso patrimonial y aplicación de nuevas tecnologías a su estudio

  1. García Ortiz de Landaluce, Esperanza
Supervised by:
  1. José Ramón Rodríguez Pérez Director
  2. Félix Pérez Lorente Director
  3. Esperanza Fernández Martínez Director

Defence university: Universidad de León

Fecha de defensa: 29 January 2016

  1. Xabier Pereda Suberbiola Chair
  2. Luis Carcavilla Urquí Secretary
  3. Marco Romano Committee member

Type: Thesis


Dinosaur tracks are a heritage resource of great interest due to both their scientific and their tourist and/or educational value. Moreover, the interest in their study has increased significantly in recent years, as evidenced by the large number of papers on this matter published in scientific journals. Spain has a rich record of sites with this type of fossils, mainly concentrated in a geological region known as Cameros Basin, which includes territories belonging to the provinces of La Rioja, Soria and Burgos. This Doctoral Dissertation is focused on the study of the dinosaur tracksites of La Rioja, the region with the largest concentration of sites of this type in Spain and one of the most significant areas of global fossil record for this kind of fossils. In this area, the number of tracksites discovered is constantly growing which, together with the lack of means and resources for their study, makes it necessary to establish a methodology for their valuation in order to set up priorities for intervention as objectively as possible. Furthermore, the growing interest in the use of this heritage as a tourist attraction and as a socio-economic development enabler makes it essential to update heritage studies about these outcrops and to create new tools for their integrated management. In addition to the foregoing, one of the current challenges for scientists is the use of new digital tools, such as Geographical Information Systems (GIS) or photogrammetry, to improve the quality and potential of scientific studies and to mitigate or resolve some of the heritage problems. This work is focused on updating the information available of these sites, as well as on the analysis of their heritage condition. It is also focused on improving the techniques used in their study, through the development and implementation of useful tools that facilitate the proper management of these assets, taking into account the particularities and the diversity of these tracksites, and even, the degradation processes to which they are subjected. With reference to the applied methodology, the initial stage was the in-depth compilation of information about the studied sites, which was available in diverse bibliographical sources. This was completed and updated thanks to in situ recognition of the outcrops during field campaigns, in which datasheets specifically designed for data collection were used. Both phases of the work have materialised in the update of the inventory of sites to a total of 186, and the creation of three tools for their management. On the one hand, two databases have been developed: 1) the dinosaur tracksites of La Rioja database (BDYIR), with orderly information of each of the sites; and 2) the other Mesozoic sites of La Rioja database (OYMER), with data about other outcrops ranging the same age but with other type of fossils. On the other hand, a BDYIR management system accessible through a website was designed in order to enable the access to data and its continuous updating. Furthermore, the heritage study of any place considered of interest should heed its state of preservation. Thanks to the field work carried out over several years, a state of progressive deterioration at the tracksites of La Rioja was detected. This fact, coupled with the lack of a general agreement in the bibliography about how to assess the risk of degradation, generated the need to develop a protocol to characterise the risk of degradation of these places, enforceable to other geosites and therefore, suited to be used widely. This methodology is based on analysing the susceptibility of a geosite to be damaged or destroyed due to both intrinsic (fragility) and extrinsic (natural and anthropic vulnerability) factors, as well as taking into account the threats arising from the public use XXII of the place and the territory. It allows identifying the causative agents of deterioration, and the processes that they trigger, with a proposal for measures to mitigate their effects. This methodology was applied to the tracksites of La Rioja, allowing the recognition of active degradation processes in various outcrops, some of which show significant degradation at human timescale. Besides, it was tested in two international tracksites, Sezze (Italy) and Aït Blal (Morocco), in order to validate its use and contribute to the planning of management strategies for these two places. During field campaigns, the geographic coordinates of 164 sites of the inventory were also measured with GPS. With these locations and the datasheets, a layer of georeferenced information (yacimientos_poligono.shp) with a table containing the attributes of each of the tracksites was created. In addition, other thematic layers of geographical information (lithology, vegetation, altitudes, etc.) from different sources (IDERioja, IGME, CNIG, etc.) were downloaded and implemented in a geographical database. The result has been the design of a GIS with useful information for the management and analysis of the tracksites of La Rioja. Additionally, several spatial analyses were performed with this GIS in order to identify and characterise those sites exposed to certain threats by processes related to the risk of degradation. Thus, close range photogrammetry techniques were applied in three of the inventoried sites with the two-fold aim of: 1) allowing a deeper analysis of its content, and 2) digitally preserving the outcrop. From a scientific and heritage point of view, some of the studied sites are considered particularly interesting because they contain evidence of some types of behaviour in dinosaurs. In Valdecevillo (2VA section) and Valdebrajes tracksites, the photogrammetric work was complemented by an accurate topographical survey, which allowed georeferencing the orthophotos, the digital elevation models and the outlines of tracks and trackways. The precision and accuracy of the results enabled to corroborate the hypothesis of herding in both sites. On the other hand, a less accurate technique of close range photogrammetry was applied in La Rueda tracksite, but it requires little experience and a lower cost. 3D models of the surface of the site were obtained with this technique, which allowed seeing and studying the footprints, despite its shallow nature and the uneven surface of the outcrop. On balance, this Thesis shows the usefulness of new techniques such as GIS and photogrammetry for scientific studies (e.g., testing hypotheses of gregariousness) and for the digital preservation of sites with palaeontological interest, thanks to its application in the tracksites of La Rioja. Furthermore, the inventory of tracksites in this area is updated to 186 places and, with these data, protocols to determine the risk of degradation and the priority of action have been developed, being applicable to any place of geological interest.