Dolores Pereira

Characterization of serpentinites to define their appropriate use as dimension stone

Abstract Many questions arise when considering the appropriate use of building stones such as serpentinites. The commercial names of these rocks, collectively grouped as ‘Green marbles’, have no correspondence to their actual mineralogy, geochemistry and/or physical characteristics. Serpentinite being the hydrated product of an ultramafic parent rock and not a metamorphic product of limestone as implied by the term ‘marble’. However, the serpentinites most widely used for ornamental purposes come from India (e.g. Rajasthan Green, Emerald Green) and in these the original mineralogy has been almost completely converted into carbonates. By contrast, serpentinites from elsewhere (e.g. Vermont Verde Antique from the USA and Verde Pirineos from Spain) do preserve some of their original mineralogy. The different physical and chemical behaviour of carbonates and serpentine minerals can result in significantly different behaviour of commercial building stones. Thus, carbonates are resistant to weathering but suffer from acidic cleaning agents in interior use; whereas serpentinites, with a high content of talc, used on external faces undergo an increase in volume and a consequent rapid degradation. Accurate and precise characterization of serpentinites, including information on their mineralogy and geochemistry (including major, trace and volatile elements together with oxygen isotopes), in conjunction with their physical properties, would enable architects to select the appropriate interior or exterior use of these handsome building stones.

Building stone as a part of a World Heritage Site: ‘Piedra Pajarilla’ Granite and the city of Salamanca, Spain

Abstract Building stone is a significant product in most human communities. While some civilizations paid more attention to the aesthetics of the stone, others focused more on physical properties, especially durability, as well as the ease of transportation to construction sites. These latter issues determined which rocks were exploited, in preference to others, for centuries. Ancient Roman society became expert in constructing durable engineering projects (e.g. roads, bridges and aqueducts). Most of their projects were realized using local granites and most remain in excellent condition today. The historic cores of many European cities need to preserve their integrity, using the original building stone of the city both for new construction and for restoration. A supply of the original material should be preserved in order to avoid use of alternative building stones when restoring old monuments. In Salamanca, a specific unique granite was used to build many of its monuments that are now preserved as part of the UNESCO World Heritage Site. An attempt to preserve this architecture and restore it, when needed, with the original material is the main focus of our paper, as some experiences using other types of rocks have led to unfortunate results.

The Sierra Nevada serpentinites: the serpentinites most used in Spanish heritage buildings

Abstract Serpentinites from Sierra Nevada (Granada, south of Spain) have traditionally been used as ornamental elements in historical buildings, both indoors and outdoors. The cathedral, the Palace of Charles V, the Royal Chancellery in Granada and some others are good examples of their use. Outside Granada, the serpentinites are seen at the monastery of El Escorial, The Royal Palace and the convent of Las Salesas Reales, all of them part of Madrids architectural heritage, although there are much more examples to be found across the country. There are two quarries located in Sierra Nevada that supplied all the material to make the different elements in the above buildings. In this work, we report a thorough characterization of the main characteristics of the serpentinites from Sierra Nevada in order to propose this stone as a possible candidate as a ‘Global Heritage Stone Resource’. This work is important for duly recognizing a natural stone that has been profusely used in the past in the construction of a magnificent heritage of important cities, and historical quarries should be protected so that they can provide original material if required to do so in the future.

Improving Female Participation in Professional Engineering Geology to Bring New Perspectives to Ethics in the Geosciences

Many papers have been published related to the retention and advancement of women in sciences. Engineering geology is one of the professional areas where women have not yet broken the gender barrier. The research issues of this paper are focused on why female students “leak out” at the end of engineering geology studies, and what can be done to encourage them to complete their degrees with an engineering career in mind. The author has studied students’ preferences of the final year project required to complete their degree at the University of Salamanca (Salamanca, Spain). It has been found that most female students are choosing a more theoretical final project instead of a practical one relevant to professional employment, contrary to their male peers. Focus group meetings with the students showed that at the end of five years of engineering geology training, many female students, unsatisfied with the content of their courses, feel that their expectations had not been met. They often have preferences for traditional geology rather than applied branches of the subject. Also, they do not feel comfortable with future job prospects in the profession. From the findings of this research it is clear that tutoring and mentoring would be valuable from the beginning of studies to allow all students to become aware of the content and the potential outcomes of engineering geology studies. In the case of female students, it is particularly important for them to know from the very start that they are about to join what is still a man’s world but that they are capable of achieving just as much as men can in the profession. Most importantly, the involvement of more female engineers in professional engineering, including teaching duties, should serve as example and role models in students’ education and future careers.

Phytogeochemical, geographical and vulnerability study of the Paleosubtropical element Notholaena marantae subsp. marantae (Sinopteridaceae) at the western edge of its range

Serpentine outcrops are distinct from their background geological context, as they are often isolated from one another, and provide a home to a significant number of rare or endemic taxa. The aim of this study was to assess the Portuguese populations of one such taxon, Notholaena marantae subsp. marantae, including information on its biogeography, habitat, geographical range and conservation status. A detailed study was also made of the endemic association Notholaenetum marantae, a member of the Phagnalo saxatilis-Cheilanthion maderensis alliance, a type of vegetation included in the EU Habitats Directive 92/43/ECC. The distribution of Notholaena marantae was highly fragmented, with two sites accounting for over 50% of the total number of individuals recorded. The presence of N. marantae is associated with that of ultramafic rocks, which show specific geochemical features. The conservation status of the species is a cause for concern. We propose that the species be considered ‘vulnerable’ according to the criteria of the IUCN (2001), and that areas where its populations grow be protected. This study confirms the endemic status of N. marantae subsp. marantae in Portugal and the importance of the conservation of its serpentine habitats.

Serpentinites from Cabo Ortegal (Galicia, Spain): a search for correct use as ornamental stones

Abstract Different varieties of serpentinites present at Cabo Ortegal were studied. For many years, the ‘Verde Pirineos’ type has been quarried and sold commercially, but its physical characteristics do not fulfil the requirements for its use as an ornamental stone. ‘Piedra de Doelo’ is the local name for a serpentinite that has been quarried and used for many centuries in a large number of historical buildings distributed throughout the area. The preservation status of the rock is very poor and the stone is severely affected by weathering. A third variety, similar to the ‘ophicalcite’ described in the literature, is currently under investigation with a view to studying the possibility of the resumption of serpentinite quarrying. Although serpentinites are commercially known as ‘green marbles’, Galician serpentinites do not fulfil the mineral requirements to be described as such. Study of the characteristics of serpentinites, including their mineralogy, may offer a clue to the correct use of Galician serpentinites.

Characterization of the Natural Variability of Macael Serpentinite (Verde Macael) (Almería, South of Spain) for Their Appropriate Use in the Building Industry

Verde Macael is a serpentinite made up mainly by antigorite, with different degrees of transformation to carbonates. It has wrongly been included under the section of marbles in industry catalogues. In Macael (Almeria, South Spain) there are different quarries extracting this natural stone. Although in most outcrops rocks are similar, different characteristics are detected derived from transformation processes. The results are shown in variations in mineralogy, texture and/or in the physical and mechanical properties, conditioning the behaviour of the natural stone once emplaced in a building. The main factor of variation is related to the carbonation degree. Due to its late use in some significant heritage buildings such as the cathedral of Nuestra Senora de La Almudena in Madrid or many civil buildings all over the country, a whole characterization of the material from the main quarries is an important task we face in this work. We test the main parameters that determine its proper use in civil construction. This will help to avoid early deterioration of the natural stone and subsequent costs for restoration. Due to the characteristics of Verde Macael this rock is a possible candidate to Global Heritage Stone resource designation.

Piedra Pajarilla: a candidacy as a global heritage stone resource for Martinamor granite

Abstract Piedra Pajarilla is the local name under which the Martinamor granite was known when it was quarried during the 19th century. It is a leucogranite of Hercynian age, and here we present its formal nomination as a ‘Global Heritage Stone Resource’. Piedra Pajarilla fits the proposed designation because it has been used for centuries in the construction of major historical and famous buildings in Salamanca, leading the city to being included in the UNESCO World Heritage list in 1988. Piedra Pajarilla is no longer quarried, and this nomination will help to maintain the historical quarry for the restoration of the monuments if blocks need to be replaced.

Global Heritage Stone

This volume provides a synopsis of current research on volcanic processes, as gained through the use of palaeomagnetic and rock magnetic techniques. Thermoremanent magnetization information provides a powerful means of deciphering thermal processes in volcanic deposits, including estimating the emplacement temperature of pyroclastic deposits, which allows us to understand better the rates of cooling during eruption and transport. Anisotropy of magnetic susceptibility and anisotropy of remanence are used primarily to investigate rock fabrics and to quantify flow dynamics in dykes, lava flows, and pyroclastic deposits, as well as identify vent locations. Rock-magnetic characteristics allow correlation of volcanic deposits, but also provide means to date volcanic deposits and to understand better their cooling history. Because lava flows are typically good recorders of past magnetic fields, data from them allow understanding of changes in geomagnetic field directions and intensity, providing clues on the origin of Earth’s magnetic field.

Students’ Final Projects: An Opportunity to Link Research and Teaching

The final project that students have to complete before finishing their degree in the new adapted system to Bologna in Spain is an opportunity to link research and teaching. This experience has been ongoing for several years now within our research group and the engineering geology course. These studies had a final project in the non-adapted system, and this will serve as experience for the system to come. Teaching staff must be aware of the current lack of independence that students have when working on their own and how the new system will attempt to remedy this failure by working the different competencies. The involvement of students in research groups has shown that they feel more confident if their opinion is taken into account when they are carrying out a research project, leading them to feel gratified if they appear in the authorship of papers and abstracts concerning their work presented at international congress. This helps to increase their motivation as professionals in the last stages of their university studies.