Archaeological research of ancient mining landscapes in Galicia (Spain) using Airborne Laser Scanning data.

Seediscussions,stats,andauthorprofilesforthispublicationat:https://www.researchgate.net/publication/266422220 ArchaeologicalresearchofancientmininglandscapesinGalicia(Spain)usingAirborneLaserScanningdata CONFERENCEPAPER·JULY2014 DOI:10.13140/2.1.3122.5608 READS 73 5AUTHORS,INCLUDING: JoãoFonte SpanishNationalResearchCouncil 13PUBLICATIONS1CITATION SEEPROFILE HugoPires UniversityofPorto 12PUBLICATIONS9CITATIONS SEEPROFILE LuisGonçalves-Seco InstitutoSuperiordaMaia 11PUBLICATIONS49CITATIONS SEEPROFILE A.M.C.Lima UniversityofPorto 44PUBLICATIONS75CITATIONS SEEPROFILE Availablefrom:HugoPires Retrievedon:31January2016 A reconhecida importância dos valores patrimoniais do vale superior do Rio Terva, em que se destaca o Complexo Mineiro Antigo, classificado como Sítio de Interesse Público, justificou um esforço de convergência de interesses e de ações entre o Município de Boticas e a Universidade do Minho, no sentido de garantir uma valorização sustentada e uma gestão integrada do valioso património identificado, tendo em vista promover a sua difusão alargada, a criação de serviços, o aumento da oferta cultural de Boticas e a internacionalização da história milenar e da identidade do seu território. Esta publicação corresponde às atas do simpósio internacional Paisagens Mineiras Antigas na Europa Ocidental. Investigação e Valorização Cultural, que encerrou o projeto “Conservação, Estudo, Valorização e Divulgação do Complexo Mineiro Antigo do Vale Superior do Rio Terva, Boticas”, iniciado em 2006 e financiado por fundos europeus no quadro do EEC PROVERE AQUANATUR-PA/1/2011, do Eixo Prioritário II-Valorização Económica de Recursos Específicos, do ON.2-O Novo Norte. O Simpósio estruturou-se em dois temas, Investigação e Valorização, através dos quais se pretendeu dar a conhecer o estado da arte, no ocidente europeu, das investigações das paisagens mineiras antigas e dos projetos de valorização das paisagens culturais correlacionadas, abordando-se, para o primeiro tema, questões relacionadas com os objetivos, metodologias, resultados e perspetivas de desenvolvimento futuro das investigações e, para o segundo tema, questões relacionadas com as razões e processos de criação de estruturas de gestão de paisagens culturais, respetiva componente de investigação, modelos de gestão implementados e desafios para o futuro. Paisagens Mineiras Antigas Europa Ocidental na Investigação e Valorização Cultural PAISAGENS MINEIRAS ANTIGAS NA EUROPA OCIDENTAL Investigação e Valorização Cultural Atas do Simpósio Internacional Boticas, 25/26/27 julho 2014 PAISAGENS MINEIRAS ANTIGAS NA EUROPA OCIDENTAL 7 6 ÍNDICE PAISAGENS MINEIRAS ANTIGAS NA EUROPA OCIDENTAL Apresentação Prefácio ARTIGOS INVESTIGAÇÃO Carla Martins Paisagens mineiras em Portugal. Balanço da investigação. Roberto Matías Rodríguez La investigación de la minería aurífera romana en España: planteamientos del pasado y nuevas perspectivas. Luisa Dallai e Giovanna Bianchi Mining archaeology and archaeometallugy in souther Tuscany (central Italy): a research project. Beatrice Cauuet Gold and silver production in Alburnus Maior mines from Roman Dacia. Dynamics of exploitation and management of the mining space (Rosia Montana, Romania) VALORIZAÇÃO Luís Fontes e Mafalda Alves O Parque Arqueológico do Vale do Terva. Um Projecto de Paisagem Cultural. Maria Ruiz del Árbol Moro Scientific research and heritage management at Las Médulas: a history of encounters and missed encounters Silvia Guideri Valorizzazione di un Paesaggio ad Elevato Valore Culturale: il Sistema dei Parchi della Val di Cornia nella Toscana Mineraria Sergiu Nistor The Romanian Mining Cultural Landscape: from silence to scream POSTERS INVESTIGAÇÃO Bruno Osório The Iron Age Settlements and Landscape at the TVAP Bruno Pereira, João Azevedo, João Oliveira Remote sensing methods and distanced analysis of geological prospecting application archaeology Carla Ferreira, Gill Plunkett, Luís Fontes The 4th and 5th centuries AD vegetation in the Upper Terva valley and Cabreira Mountain Emmanuelle Meunier Thinking NW Iberian tin mining: wich basis for wich perspectives? Gabriel Munteanu Gold-Silver Antique Mining “Districts” from Metaliferi Mountains, Romania. Geographic, Geologic and Archaeological Crosscutting Perspectives. The case of Bucium-Butura-Vulcoi-Corabia mining Complex João Fonte, Hugo Pires, Luís Gonçalves-Seco, Roberto Matías Rodríguez, Alexandre Lima Archaeological research of ancient mining landscapes in Galicia (Spain) using Airborne Laser Scanning data 17 10 12 9 29 65 85 113 143 157 175 191 193 194 195 196 197 198 9 8 ÍNDICE José Manuel Brandão Coal mines? That was more than fifty years they close, he said! Maurício Marques Guerreiro Archaeology of Architecture at the TVAP. The Ardãos village case study. VALORIZAÇÃO Cláudia V. Ferreira e Luís Ferreira Touristic Potential of Tungsten Mines Heritage – Rio de Frades (Arouca) B. Cristina Fernández, F. Comendador Rey, N. Amado González Heritage landscape of metal mining in the Upper Támega Valley (Ourense, Spain): Arcucelos mines Cristina Madureira; P. C. Machado; C. Marques (translation) Santa Justa and Pias Mountains. Why Protect and Value? Katarzyna Jarosz Romanian gold mines in danger Luís Fontes The classification of the Ancient Mining Complex of the Terva River Upper Valley as a Site of Public Interest Mafalda Alves The PAVT Project. Living (in) Landscape 199 200 201 202 203 204 205 206 Archaeological research of ancient mining landscapes in Galicia (Spain) using Airborne Laser Scanning data João Fonte1,2, Hugo Pires2, Luís Gonçalves-Seco1,2,3, Roberto Matías Rodríguez4, Alexandre Lima5 1 Instituto de Ciencias del Patrimonio (Incipit), Consejo Superior de Investigaciones Cientificas (CSIC), Espanha 2 Centro de Investigação em Cências Geo-Espaciais (CICGE), Faculdade de Ciências, Universidade do Porto, Portugal 3 ISMAI – Instituto Superior da Maia, Portugal 4 Fundación Cultura Minera, León, España 5 Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências, Universidade do Porto, Portugal 198 INVESTIGAÇÃO Introduction and objectives The use of techniques based on 3D point-clouds for modeling and documentation of cultural heritage1 and the mapping and survey of archaeological landscapes 2 has evolved remarkably and it’s becoming of a widespread use. In the case of the mapping and prospection of mining landscapes, areas which are usually densely forested, the identification and documentation of archaeological features, coupled with its size and complexity, is still very problematic when relying on well-known methods such as photointerpretation or fieldwork. The introduction of airborne laser scanning (ALS) or airborne Light Detection and Ranging (LiDAR) helped to overcome this problem because of its unique capability to penetrate vegetation canopies, allowing the documentation of the underneath topographic surface and thus the identification of archaeological remains3. The effectiveness of airborne LiDAR in detecting new archaeological sites and features and in improving the documentation of the already known is well proved, so ALS has completely revolutionized the area of archaeological survey4. Given this, we present in this study some preliminary results related to the potential of airborne LiDAR to archaeological research of ancient mining landscapes. Study areas We have selected two study areas in Galicia, Spain (Fig. 1), comprising different types of Roman mining: one in a primary context (Carballiño) (Fig. 2-a and c) and the other in a secondary one (Os Milagros do Monte Medo) (Fig. 2-b and d). The Carballiño area is located in the Galicia-Trás-os-Montes Zone (GTMZ zone)5. The GTMZ belongs to the internal zone of the Hercynian belt and is composed of a relative autochthonous and parautochthonous units overthrusted by allochthonous complexes. This area is located in the Schistose Domain, which is composed by a monotonous sequence of schists crosscutted by the so called G2 granites (Carballiño massif) that are syn-D3 two micas granites and leucogranites6. Gold mineralizations are spatially associated with G3 granites (Boborás and Irixo massifs)7. G3 granites are biotite-dominant two mica granites8 (Fig. 3-a). Locally called Gobras de Madarmás, it was exploited in quartz veins (with strike N10ºW that agree with the open pit main orientation), where arsenopyrite, scorodite and gold can be found in veins9. The Os Milagros do Monte Medo area is a secondary deposit in opposition to the primary deposits of Carballiño. The geology is very simple and the Romans exploited the horizontal layers of quartz conglomerates, deposited over barren clay-sand formations, all from the Quaternary period10 (Fig. 3-b). LiDAR data processing The PNOA (Plan Nacional de Ortofotografía Aérea), the Spanish National Plan for Aerial Orthophotography (http://www.ign.es/PNOA/), promoted by the Spanish National Geographic Institute (IGN), has made public available an almost complete LiDAR and orthophotographic coverage of Spain. In our study areas, the aerial images for orthophoto production were acquired in June 2011, while the LiDAR data were acquired in September 2011 using an IGI LM 5600 sensor, operated at a laser wavelength of 1064 nm from a flight altitude of 1000 to 1800 m (above sea level). The beam divergence was 0.5 mrad, the pulsing frequency 70 kHz, the scan frequency 50 Hz, and the scan angle ±10. Up to four returns per pulse were registered, with an average measuring density of about 0.5 points per square meter. To generate the Digital Terrain Models (DTM), the Adaptive Morphological Filter (AMF)11 was used for filtering terrain points. A kriging interpolation method with a 1 m cell size was used to generate the DTM. To enhance the contrast of archaeological features, we have applied the Morphological Residuals Model (MRM)12, that uses a mesh decimation algorithm that allow us to discriminate between positive and negative microtopographies at a local scale, representing real changes in elevation rather than calculations based on steepness and slope direction or light exposure. Results As we can see from the chosen examples, Romans were able to mine primary and secondary gold deposits. In case of the primary ones, they tend to be limited in space, since they usually exploited structural (linear) enrichments. That is not the case for secondary deposits, since they need to wash a huge amount of rock remains, that Las Médulas is an extreme example, in order to extract the low gold content. In the Carballiño area, one can clearly appreciate the contrast between the original and the modified landscape, both by the mining activities and the construction of a hillfort13. The morphology of the mining operations indicates that the excavation was applied directly onto a vein or veins system sharply defined. The southern extension of the open-pit should be understood as a need to drain the mining works. In the case of the Os Milagros do Monte Medo exploitation, it occupies an area of approximately 6 km2, dug on alluvial Plio-Quaternary or earlier belonging to an ancient river channel, now defunct. Despite the vegetation that nowadays covers the mined area, is possible to reconstruct the mining structures from historical aerial photos, before afforestation has been made14 (Fig. 5-b). One can notice several levels of operation (up to 3), conducted on the remnant river terraces, using different methods like “trenchchannels” (Fig. 4-1) and “stream-cuts” (Fig. 4-2), which in some cases tend to overlap, and “convergent furrows” (Fig. 4-3). When compared to the previous photo interpretation (Fig. 5c), the MRM image shows a greater level of detail of the mining structures (Fig. 5d). Final remarks The MRM images have allowed an immediate general display of the surface mining operations without the need of a detailed processing of aerial photos, a task that can be very demanding when dealing with complex structures, as in this case. Thus, the initial work of photo-interpretation is speeded, although one cannot completely ignore a more detailed and integrated study of the landscape and, of course, ground-truthing the archaeological evidences. Note:This work has been supported by the Archaeolandscapes Europe project (www.archaeolandscapes.eu). The first author acknowledges the Portuguese Science Foundation (FCT) for the SFRH/BD/65143/2009 grant. Archaeological research of ancient mining landscapes in Galicia (Spain) using Airborne Laser Scanning data João Fonte1,2, Hugo Pires2, Luís Gonçalves-Seco1,2,3, Roberto Matías Rodríguez4, Alexandre Lima5 1 Instituto de Ciencias del Patrimonio (Incipit), Consejo Superior de Investigaciones Cientificas (CSIC), Espanha 2 Centro de Investigação em Cências Geo-Espaciais (CICGE), Faculdade de Ciências, Universidade do Porto, Portugal 3 ISMAI – Instituto Superior da Maia, Portugal 4 Fundación Cultura Minera, León, España 5 Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências, Universidade do Porto, Portugal Figure 5 - MRM results from Carballiño (c) and Os Milagros do Monte Medo (d) compared to previous archaeological interpretations: open-pits and hillfort from Carballiño over a topographic map (a) (AMADO-ROLÁN 2005) and exploitation phases of Os Milagros do Monte Medo traced over the 1956 USAF aerial photographs (b) (SÁNCHEZ-PALENCIA et al., 2009) Figure 2 - Carballiño: Orthophoto (a) and Digital Surface Model (DSM) (c); Os Milagros do Monte Medo: Orthophoto (b) and DSM (d) Figure 4 - DTM and MRM of Carballiño (a and c) and Os Milagros do Monte Medo (b and d) respectively Figure 1 - Location of the study areas Figure 3 - Geological maps at 1:50.000 scale: Carballiño region (a), Os Milagros do Monte Medo (b) and Au and Sn-W mineralizations and relationships with different granites in the surroundings of the Carballiño study area (1) (Gloaguen 2006) References 1De Reu, J., PLeTS, G., VeRHoeVen, G., De SMeDT, P., BATS, M., CHeRReTTé, B., De MAeyeR, W., DeConynCk, J., HeRReMAnS, D., LALoo, P., VAn MeiRVenne, M. and De CLeRCq, W. Towards a three-dimensional costeffective registration of the archaeological heritage. Journal of Archaeological Science, 2013, vol. 40, nº 2, p. 1108-1121. 2 DoneuS, M., BRieSe, C., FeRA, M. and JAnneR, M. Archaeological prospection of forested areas using full-waveform airborne laser scanning. Journal of Archaeological Science, 2008, vol. 35, nº 4, p. 882893. 3 CRuTCHLey, Simon and CRoW, Peter. The Light Fantastic: Using Airborne Lidar in Archaeological Survey. Swindon: english Heritage. 2009. 4 oPiTz, Rachel and CoWLey, David. Interpreting Archaeological Topography: Lasers, 3D Data, Observation, Visualisation and Applications. Oxford: Oxbow. 2013. 5 FARiAS, P., GALLASTeGui, G., GonzÁLez LoDeiRo, F., MARquÍnez, J., MARTÍn PARRA, L. M., MARTÍnez CATALÁn, J.R., De PABLo MACÍA, J. G. and RoDRÍGuez FeRnÁnDez, L. R. Aportaciones al conocimiento de la litoestratigrafía y estructura de Galicia Central. 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Javier, SASTrE-PrATS, Ines, CurráS-rEFOJOS, Brais, and rOMErO, Damián. Minería romana en la cuenca meridional de los ríos Sil y Miño. Revista Aquae Flaviae, 2009, nº 41, p. 285-301. Paisagens Mineiras Antigas Europa Ocidental na investigação e Valorização Cultural Simpósio internacional Boticas 25/ 26/ 27 Julho 2014