Northwest Iberian Peninsula Research Articles

New Insights into the Lateral‐Strength Variations and Depth to the Brittle‐Ductile Transition Zone in NW Iberia

AbstractThe northwest of Iberia experiences important tectonic activity that has led to several episodes of seismic swarms. Despite substantial knowledge of the surface structures that could be responsible for this activity, their distribution at depth remains unclear. Geophysical research and rheological data display important discrepancies concerning the deep structure of the area. In order to shed light on the processes that control deep seismicity and their relationship with surface structures, we combine the analysis of seismic activity in northwest Iberia with the interpretation of sandbox experiments simulating tectonic structures similar to those observed. The structural interpretation of the modeling results was conducted by analyzing the surface particle image velocimetry field. Additionally, yield strength and brittle‐ductile transition zone (BDTZ) maps were constructed from model sections. The modeling results show a direct relationship between the main active structures developed along pre‐existing weak zones and the observed variations in crustal thickness. Moreover, these thickened zones correspond to the sectors where the BDTZ in the crust deepens. Therefore, the anomalous thickness and lateral variations of the seismogenic zone cannot be solely explained by rheological or structural changes but result from a combination of factors such as fluid pressure and the location of fractures at depth, which controls the fluid migration responsible for the failure of crustal faults. These factors can trigger seismic activity at depth and may control the observed thickness variations in the BDTZ.

The Northwestern Iberian Mountains: Resilient Landscapes until the Augustan Conquest, 29–19 B.C.

ABSTRACT The Iberian Peninsula is an area of the Western Mediterranean among the most sensitive to climatic and anthropogenic change. It has formed the centre-piece of numerous palaeoenvironmental studies of mountain and valleys, covering different chronologies and historical periods. These studies, however, include no palaeoenvironmental background to the Roman military conquests of the late third to the late first centuries B.C. This paper presents palynological evidence from two Roman military camps, A Recacha and A Granda das Xarras, in the mountains of Northwest Iberia. The main results reflect anthropic activities that shaped the landscape since at least the end of the third millennium B.C., with the presence of montane heaths and deciduous forests. During the first millennium B.C., a modest increase in anthropic activity was detected, possibly due to seasonal grazing. Throughout the Roman conquest, slightly increased signs of anthropogenic activity on the local landscape are detected, leaving a landscape which has changed little throughout the two thousand years that have since passed.

Explicaciones históricas de la huella genética norteafricana en el noroeste de Iberia

Se analizan siete estudios recientes sobre la huella genética norteafricana en Iberia. En todos ellos se observan las mayores concentraciones de características genéticas asociables con el Magreb en el noroeste de la Península Ibérica, una región no sólo alejada de África sino también sujeta al control político andalusí durante menos tiempo que prácticamente cualquier otra región peninsular. Los intentos para buscar un contexto histórico para tan anómala distribución han sido lastrados por una lectura algo simplista de la historiografía, en detrimento de cualquier explicación altomedieval, favoreciendo en cambio soluciones alternativas más historio-gráficamente problemáticas. En consecuencia, estos estudios han sido generalmente ignorados por los medievalistas, así agravando la falta de diálogo entre ambas disciplinas. Sugerimos que la percibida paradoja entre un breve periodo de control político y una profunda huella genética debe servir para cuestionar la interpretación tradicional de los acontecimientos del siglo VIII, y así obligarnos a contemplar una mayor influencia Bereber en el noroeste, en vez de conducir a la marginalización por parte de los historiadores de tan llamativos resultados.

Del momumento a la dominación social. Propuestas para el análisis de los castillos altomedievales como centros de poder en el noroeste de la península ibérica

Este trabajo presenta un estado de la cuestión de dos perspectivas de análisis para el estudio de los castillos medievales desarrolladas en Europa durante las últimas décadas. En primer lugar, se exponen algunas de las reflexiones con las que han contribuido los estudios que conciben los espacios fortificados como símbolos de poder, desarrollados fundamentalmente por las escuelas británica y francesa. Seguidamente, se hace un sintético balance de la investigación que, aprovechando el concepto de incastellamento, ha centrado su interés en las funciones sociales y económicas vinculadas a los asentamientos fortificados y a su dominio sobre el territorio. Ambas corrientes se ponen en relación con el bagaje de los estudios sobre los castillos del noroeste de la península ibérica, donde su aplicación ha llegado de forma desigual e intermitente.

The Presence of Decayed Wood in Iron Age Contexts of Northwest Iberia: Wood-borer Galleries and Fungal Hyphae

ABSTRACT Decayed wood occurs relatively frequently in charcoal assemblages from Iron Age sites in northwest Iberia, and the presence of fungal hyphae and wood-borer galleries has been identified in charred wood remains from different kinds of archaeological contexts. This study analysed the evidence of decayed wood, as a result of fungal and insect attack, including the affected taxa and other dendrological attributes, their association with firewood remains or evidence of wooden crafts and other contextual evidence, from nine Iron Age sites. The data available to date indicate that Corylus avellana, Quercus sp. deciduous, Alnus sp. and Fabaceae have been affected the most by the action of fungus and wood-borers, and evidence of xylophagous activity is correlated with the occurrence of fire events and/or the presence of worked wood. This paper highlights the potential of combining taxonomical identification with taphonomical and dendrological attributes to understand the processes of wood degradation in archaeological contexts.

Analysis of portable rock art from Foz do Medal (Northwest Iberia): Magdalenian images of horses and aurochs

Studies focusing on Palaeolithic portable rock art have a long tradition in Europe. Nevertheless, they tend to only focus over formal and stylistic criteria of the motifs, important as they provide chronologies for cave art. This article proposes a multiple approach to a sample of 25 engraved plaques of the Foz do Medal archaeological site, where horses and aurochs were depicted, in order to construct a preliminary model able to guide the future analysis of the whole collection composed of more than 1500 fragments. On the one hand, relevant archaeological data was collected and systematized into a database that can be subjected to statistical analysis, for which we develop different variables and their respective attributes. On the other hand, laboratory techniques of analysis and examination of materials were applied, valuing the motifs details, their potential surface treatment by fire or pigments ornamentation, as well as the identification of raw materials and their origins. In this article, we present the obtained results, which allow us to propose some hypotheses regarding the social importance of this specific kind of artefact, as well as its possible manipulations.

The impact of climate change on the geographical distribution of habitat-forming macroalgae in the Rías Baixas

In the current scenario of climate change characterized by a generalized warming, many species are facing local extinctions in areas with conditions near their thermal tolerance threshold. At present, the southern limit of the geographical distribution of several habitat-forming algae of cold-temperate affinities is located in the Northwest Iberian Peninsula, and the Rías Baixas may be acting as contemporary refugia at the range edge. Therefore, it is necessary to analyze future changes induced by ocean warming in this area that may induce changes in macroalgae populations. The Delft3D-Flow model forced with climatic data was used to calculate July–August sea surface temperature (SST) for the present (1999–2018) and for the far future (2080–2099). Mean daily SST was used to develop and calibrate a mechanistic geographical distribution model based on the thermal survival threshold of two intertidal habitat-forming macroalgae, namely Himanthalia elongata (L.) S.F.Gray and Bifurcaria bifurcata R. Ross. Results show that H. elongata will become extinct in the Rías Baixas by the end of the century, while B. bifurcata will persist and may occupy potential free space left by the decline in H. elongata.

Revision of the occurrence of muskox (Ovibos moschatus Zimmermann 1780) from the Gravettian of Arbreda Cave (Serinyà, northeastern Iberian Peninsula): new insights for the study of Iberian cold‐adapted faunas

During the Last Glacial cycle (MIS 4 to MIS 2), the isthmic Pyrenees mountain range acted as a biogeographical barrier, effectively restricting faunal exchanges to its western and eastern terminations. The study of the composition of megaherbivore communities has revealed the transitional character of the Cantabrian region (northwest Iberian Peninsula) during the MIS 3, between western European cold faunas and southern Iberian temperate faunas. In the Catalan area (northeastern Iberian Peninsula), cold‐adapted faunas are frequently recorded during the cold pulses of MIS 3 and MIS 2, albeit to a lesser extent. In the present paper, we provide the first direct evidence of a muskox record in the Iberian Peninsula, together with a morphometric study and the results of collagen δ13C and δ15N analysis. The results reveal that the Arbreda specimen fits biometrically within the Late Holocene Umingmak specimens (Banks Island, Canada). Moreover, its isotopic values fall into the range of Late Pleistocene Mammoth steppe muskoxen, which indicates a typical ecological behaviour for muskox. Indeed, it suggests a niche partitioning of this cold‐adapted specimen in relation to other Gravettian Iberian fauna. Chronologically, this occurrence is interpreted as an isolated southward expansion of the biogeographical limits of muskox during the Greenland Stadial 4, in the latest MIS 3.

Periphyton colonization and changes in the diatom assemblages of an artificial urban pond

Artificial ecosystems are sometimes the only opportunity for citizens to experience nature. Maintaining their quality is essential for continuing to enjoy the ecosystem services. We studied an urban pond in the Northwest Iberian Peninsula (Aveiro, Portugal) as a model for testing the suitability of diatom assemblages and indices of water quality in these particular ecosystems. Weekly sampling of three replicas was performed over 28 days on stones and ceramic tiles in a shaded site (Site-SH) and in a sunnier one (Site-SU). The best model of the distance-based analysis included temperature and NH4+as the variables that best explained the diatom assemblages (R 2= 0.43). Chlorophyll-α taken as a proxy for algae biomass, and ash-free dry mass increased until the third week, when a turbid runoff entered the system. After this disturbance, chlorophyll-α increased only at Site-SH (from 14.4 mg m –2 to 62.4 mg m–2); ash-free dry mass increased at Site-SU (from 7.2 mg m–2 to 42.3 mg m–2). The Specific Polluosensitivity Index of the diatoms showed low values below 16 that further decreased with the incubation time. Shannon diversity did not vary between sites, while ANOSIM (analysis of similarity) enabled the identification of differences in the species composition among sites and over time. Cyclotella meneghiniana and Sellaphora nigri were abundant at both sites, but other species showed a prevalence to one of the sites: Nitzschia amphibia and Gomphonema parvulum dominated at site-SH, whereas Amphora pediculus and Grunowia solgensis were abundant at site-SU. This study provides evidence that the use of benthic diatoms is a useful tool for evaluating the ecological potential of artificial ecosystems. Moreover, such systems in the close vicinity of urban areas need better management and monitoring to reduce the risk of deterioration.

Technological changes and chrono-cultural boundaries: The role of expedient technologies in the upper paleolithic

A cursory glance at the technical behaviors of Paleolithic hunter-gatherers suggests that disparate investment in tool production played a role in the variability of lithic assemblages. Expedient technologies, aimed at minimizing the time and energy invested in lithic production, are particularly common in the Lower and Middle Paleolithic, but their role in the Upper Paleolithic remains largely unexamined. The aim of this paper is to explore the potential role of low-cost technologies at times of cultural change, particularly in the Gravettian-Solutrean boundary. As an example, we will present the lithic assemblage found in level D of Valdavara Cave (north-west Iberia), dated at ca. 27–24 ka cal BP and characterized by a distinct expedient component. Then, we will contextualize Valdavara within the framework of the Cantabrian region to assess whether an increase in expedient behaviors can be recognized in other sites yielding similar dates.

Different Patterns of Ecological Divergence Between Two Tetraploids and Their Diploid Counterpart in a Parapatric Linear Coastal Distribution Polyploid Complex.

Polyploidization is a widespread mechanism of evolutionary divergence in flowering plants. Ecological divergence of polyploid lineages has been proposed as a key process shaping the distribution of cytotypes in nature (niche shift hypothesis); however, evidence for the role of niche separation in replicated diploid-polyploid species pairs is still needed. This study aimed to assess the role of abiotic factors shaping current cytotype distributions. For that, we examined the distribution and environmental niches of two varieties recognized in diploid-tetraploid Jasione maritima across the species range and within a putative contact zone on the Iberian Peninsula. We counted chromosomes, screened for ploidy across Iberian Peninsula and characterized environmental requirements using niche modeling tools. We found that J. maritima var. maritima is composed by diploids with disjunct distribution in the west coast of France and northwest Iberian Peninsula, and by tetraploids in Iberian Peninsula, while var. sabularia is tetraploid. In the Iberian Peninsula, two parapatric contact zones along a linear coastal distribution were detected, one between diploid and tetraploid var. maritima, and the other between tetraploids of the two varieties. Environmental variables of diploid populations from France are distinct from those of southern diploid populations, which are more similar to tetraploids. In general, niche modeling results are congruent with the observed distribution patterns, although the results suggest a wider contact zone between varieties and cytotypes. Tetraploids of both varieties revealed different degrees of environmental divergence in comparison with their diploid counterpart. Tetraploid var. sabularia differed environmentally from diploids suggesting niche divergence. In contrast, tetraploid var. maritima overlapped with diploid environmental niche and currently occupies its entire predicted range, whereas diploids are restricted to northern areas of their suitable environment. Differences in ecological envelopes facilitate the recognition of functional units of biodiversity within polyploid groups, allowing the study of factors related to post-polyploidization divergence. Thus, whereas changes in environmental requirements may have allowed tetraploid var. sabularia to spread in habitats not favorable to diploids, other factors are involved with the distribution of diploid and tetraploid var. maritima.

Influence of the Laser Wavelength on Harmful Effects on Granite Due to Biofilm Removal

The colonization of stone-built monuments by different organisms (algae, fungi, lichens, bacteria, and cyanobacteria) can lead to biodeterioration of the stone, negatively affecting the artistic value of the heritage. To address this issue, laser cleaning has been widely investigated in recent years, due to the advantages it offers over traditional mechanical and chemical methods: it is gradual, selective, contactless, and environmentally friendly. That said, the laser parameters should be optimized in order to avoid any by-effects on the surface as a result of overcleaning. However, as the adjustment of each parameter to clean polymineralic stones is a difficult task, it would be useful to know the effect of overcleaning on the different forming minerals depending on the wavelength used. In this paper, three different wavelengths (355 nm, 532 nm, and 1064 nm) of a Q-Switch neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) laser, commonly known as QS Nd:YAG laser were applied to extract a naturally developed sub-aerial biofilm from Vilachán granite, commonly used in monuments in the Northwest (NW)Iberian Peninsula. In addition to the removal rate of the biofilm, the by-effects induced for fluences higher than the damage threshold of the stone were evaluated using stereomicroscopy, color spectrophotometry, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results showed that different removal rates were obtained depending on the wavelength used and 532 nm obtained the highest removal level. In terms of by-effects, biotite melting was registered on all surfaces regardless of the wavelength. In addition, 532 nm seemed to be the most aggressive laser system, inducing the greatest change in appearance as a result of extracting the kaolinite crackled coating and the segregations rich in Fe, which are a result of natural weathering. These changes were translated into colorimetric changes visible to the human eye. The surfaces treated with 355 nm and 1064 nm showed lower surface changes.

Exploring the landscape dimension of the early medieval churches. A case study from A Mariña region (north-west Spain)

ABSTRACT Despite the long tradition of studies on early medieval churches, little is still known about the reasons behind the selection of specific places for building churches between the fifth to tenth centuries a.d . Thanks to some rich historical documents, the region of A Mariña (Galicia, north-west Iberia) represents an exceptional case study in order to analyse the spatial logic behind the creation of the early medieval ecclesiastical landscapes. This objective is pursued by means of the application of GIS and spatial statistics for the study of the locational patterns of these first Christian buildings. As this is a first attempt, we started from the formal analysis of topographic variables; then a settlement model for the churches was defined, and next used to analyse specific trends on their locational dynamics. The results allow us to propose that the location of the early medieval churches should be related to visual and territorial control over some specific areas of the landscape (mainly settlements and natural resources). This suggests that, despite the variety of church founders, some kind of collective planning of the church network did happen during the early Middle Ages. This fact can be historically explained as a key part of power strategies aimed at the creation of a new territorial articulation during this period.

Periglacial deposits as indicators of paleotemperatures. A case study in the Iberian Peninsula: The mountains of Galicia

AbstractIn this study, we provide a paleotemperature reconstruction based on periglacial deposits and landforms from the northwest Iberian Peninsula. We describe different types of periglacial deposits and landforms which were considered as paleoenvironmental archives. The occurrence of these landforms and deposits suggests that mean annual air temperatures must have been of ≤ −2°C for formation of block fields, block slopes and rock glaciers and ≥ 2°C for formation of stratified slope deposits, as indicated by their modern‐day analogs. The information obtained was used to construct paleotemperature maps by estimating temperature in relation to a standard altitudinal gradient. Two phases were differentiated. During the first phase, associated with the Maximum Glacial Advance (MGA) before 30 ka cal BP, the prevailing snow conditions favored the formation of stratified slope deposits and genesis of glaciers in all of the mountain systems, without the presence of permafrost. During the second phase, associated with the Glacial Maximum (GM) between 21 and 25 ka cal BP, colder conditions favored the presence of permafrost and genesis of block fields, block slopes and rock glaciers at elevations above 700 m. Temperature estimations ranged between around +6°C and − 6°C at an elevation of 2,000 m for the first phase, and between +2°C and − 10°C for the second phase. Due to limitations in estimating past climate conditions, the results should be considered as a first approximation to define northwest Iberian Peninsula paleotemperatures for the Late Pleistocene.

The role of mixing in controlling resource availability and phytoplankton community composition

We investigate the role of mixing, through its effect on nutrient and light availability, as a driver of phytoplankton community composition in the context of Margalef’s mandala. Data on microstructure turbulence, irradiance, new nitrogen supply and phytoplankton composition were collected at 102 stations in three contrasting marine environments: the Galician coastal upwelling system of the northwest Iberian Peninsula, the northwestern Mediterranean, and the tropical and subtropical Atlantic, Pacific and Indian oceans. Photosynthetic pigments concentration and microscopic analysis allowed us to investigate the contribution of diatoms, dinoflagellates, pico- and nanoeukaryotes, and cyanobacteria to the phytoplankton community. Simple linear regression was used to assess the role of environmental factors on community composition, and environmental overlap among different phytoplankton groups was computed using nonparametric kernel density functions. Mixing and new nitrogen supply played an important role in controlling the phytoplankton community structure. At lower values of mixing and new nitrogen supply cyanobacteria dominated, pico- and nanoeukaryotes were dominant across a wide range of environmental conditions, and finally enhanced new nitrogen supply was favourable for diatoms and dinoflagellates. Dinoflagellates were prevalent at intermediate mixing levels, whereas diatoms spread across a wider range of mixing conditions. Occasional instances of enhanced diatom biomass were found under low mixing, associated with the high abundance of Hemiaulus hauckii co-occurring with high N2 fixation in subtropical regions, and with the formation of thin layers in the Galician coastal upwelling. Our results verify the Margalef’s mandala for the whole phytoplankton community, emphasizing the need to consider nutrient supply, rather than nutrient concentration, as an indicator of nutrient availability.

Hydrate occurrence in Europe: A review of available evidence

Abstract Large national programs in the United States and several Asian countries have defined and characterised their marine methane hydrate occurrences in some detail, but European hydrate occurrence has received less attention. The European Union-funded project “Marine gas hydrate – an indigenous resource of natural gas for Europe” (MIGRATE) aimed to determine the European potential inventory of exploitable gas hydrate, to assess current technologies for their production, and to evaluate the associated risks. We present a synthesis of results from a MIGRATE working group that focused on the definition and assessment of hydrate in Europe. Our review includes the western and eastern margins of Greenland, the Barents Sea and onshore and offshore Svalbard, the Atlantic margin of Europe, extending south to the northwestern margin of Morocco, the Mediterranean Sea, the Sea of Marmara, and the western and southern margins of the Black Sea. We have not attempted to cover the high Arctic, the Russian, Ukrainian and Georgian sectors of the Black Sea, or overseas territories of European nations. Following a formalised process, we defined a range of indicators of hydrate presence based on geophysical, geochemical and geological data. Our study was framed by the constraint of the hydrate stability field in European seas. Direct hydrate indicators included sampling of hydrate; the presence of bottom simulating reflectors in seismic reflection profiles; gas seepage into the ocean; and chlorinity anomalies in sediment cores. Indirect indicators included geophysical survey evidence for seismic velocity and/or resistivity anomalies, seismic reflectivity anomalies or subsurface gas escape structures; various seabed features associated with gas escape, and the presence of an underlying conventional petroleum system. We used these indicators to develop a database of hydrate occurrence across Europe. We identified a series of regions where there is substantial evidence for hydrate occurrence (some areas offshore Greenland, offshore west Svalbard, the Barents Sea, the mid-Norwegian margin, the Gulf of Cadiz, parts of the eastern Mediterranean, the Sea of Marmara and the Black Sea) and regions where the evidence is more tenuous (other areas offshore Greenland and of the eastern Mediterranean, onshore Svalbard, offshore Ireland and offshore northwest Iberia). We provide an overview of the evidence for hydrate occurrence in each of these regions. We conclude that around Europe, areas with strong evidence for the presence of hydrate commonly coincide with conventional thermogenic hydrocarbon provinces.

Cleaning of gypsum-rich black crusts on granite using a dual wavelength Q-Switched Nd:YAG laser

Gypsum black crust is one of the most severe deterioration forms affecting the built Cultural Heritage (CH) worldwide. Its removal from granitic substrates is necessary since gypsum layer favours the deterioration of the rock. This study investigates the laser assisted removal of gypsum black crust, from a Hercynian granite from the North-West (NW) Iberian Peninsula. The suggested laser cleaning methodology involves the combination of two wavelengths (1064 nm and 355 nm) from a QS Nd:YAG laser system and is based on their simultaneous interaction with the involved materials at various fluence values and FIR/FUV ratios (1/1, 1/3 and 3/1). This ablative scheme was initially introduced in order to overcome undesirable discoloration issues recorded upon single wavelength laser cleaning of black crusts but its role to effectively remove different undesired over-layers was also acknowledged.The results of this study were comparatively evaluated with surfaces irradiated using one of the two specific wavelengths, while the presence of water as an enhancing cleaning agent was also considered. A multi-analytical evaluation methodology based on stereomicroscopy, Raman spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), was carried out to determine the optimum cleaning strategy in terms of crust removal effectiveness and minimisation of damages to the substrate.The optimum irradiation condition determined in this study is the simultaneous application of the two wavelengths in FIR/FUV = 1/1 ratio (with FIR = FUV = 0.3 J·cm−2) on a pre-wetted surface. Under this irradiation condition a high removal level of carbonaceous pollution particles and gypsum was achieved, without any damage to the granitic minerals in the form of melting and spallation and/or exfoliation of planes of biotite and K-feldspar and cleavage fracture of quartz.

Presence of estrogenic endocrine disruptors in three European estuaries in Northwest Iberian Peninsula (Portugal)

Estrone, 17β-estradiol, 17α-ethynylestradiol, alkylphenols and alkylphenol ethoxylates, are endocrine disruptor compounds. In Portugal, the report of male fish feminization in Minho, Ave and Mondego River estuaries made pertinent their evaluation in surface water samples. Data, got by specific enzyme-linked immunosorbent assays, showed that estrogens concentrations were lower in Minho than in Ave or Mondego estuaries: [Estrone] > [17β-estradiol] > [17α-ethynylestradiol] (p < 0.05). Converting estrogen concentrations in 17α-ethynylestradiol equivalents, the contribution of estrogens was 1.3 ng/L, 3.5 ng/L, and 2.4 ng/L, respectively, for Minho, Ave, and Mondego estuaries stressing out a high risk for local aquatic species. The concentrations of alkylphenols and alkylphenol ethoxylates were lower at both Minho and Mondego estuaries ≈600 ng/L and 2700 ng/L, respectively than at the Ave, ≈1070 ng/L and 4855 ng/L (p < 0.05). In conclusion, this study reports the first systematic data about the presence of the targeted endocrine disruptor compounds in the Minho River estuary and, in parallel, provides new information about their concentrations in two other habitats previously monitored. This study also shows that in Ave and Mondego estuaries the concentrations of industrial estrogens were still excessive, whereas the load of the pure estrogens has decreased significantly facing previous surveys.

Agro-ecological terroir units in the North West Iberian Peninsula wine regions

Viticultural zoning studies that support the definition of terroir units general follow two main approaches of geographic differentiation related either to: a) land capability or vineyard suitability, or b) grape, grapevine or wine characteristics. Both approaches are commonly considered in the definition of terroir at regional and local approaches.The purpose of this preliminary study was to develop and apply a methodology for viticultural zoning in order to establish the basis of studies on wine typicality. This will allow to question and compare the existent Protected Designations of Origin (D.O.) in the North West Iberian Peninsula wine regions (North of Portugal and Galicia-Spain).The assessment of Agro-ecological Terroir Units for viticulture includes climate and soil environmental factors selected for their relevance at regional scale, with the use of state-of-the-art variables and indices appropriate for the specified regions. The methodology considers the International Organisation of Vine and Wine guidelines (OIV, 2012), it is based upon the development of a Geographic Information System (GIS) and uses multivariate zoning with principal component analysis and clustering procedures.The results suggest that the sub-regions of Monção e Melgaço and Rías Baixas are integrated in a different terroir unit from the other Minho Sub-regions, which could give way to further inquiry with the purpose of reclassification based on studies on quality and typicality for the Alvarinho Wine.This regional and national cross-border classification provides a useful framework for territorial and viticultural policies with further validation at local and farm scales. This validation includes experimental surveys in selected vineyards for geographic differentiation of wine profiles and for supporting precision viticulture at plot and landscape scale.

Gold-bearing Plio-Quaternary deposits: Insights from airborne LiDAR technology into the landscape evolution during the early Roman mining works in north-west Spain

This article focuses on the characterization of auriferous deposits, identification of hitherto unknown Roman mining infrastructure remains, and the early attempts of exploitation carried out in north-west Iberia. The research has combined airborne laser scanning (LiDAR) and field prospection to explore the geomorphological signature and landscape transformation resulting from Roman mining works in two unknown sectors of the western Duero Meseta. The integration of geological and remote sensing information contributed to extend the Roman's mining domains, traditionally focused on the river headwaters of the north-west. The article explores the complex hydraulic system developed in the Jamuz and lower sector of the Eria river valleys, as well as the evidence of open-cast mining and their relationship with the Roman army. The results suggest that the highly dispersed and reduced dimensions of the mining sites correspond to a selected method of gold prospection, employed for the identification of viable exploitation sectors. Thus, the initiation of the mining works could have started in the Jamuz valley and developed systematically in this area, to subsequently spread towards the upstream sectors and nearby valleys. This research contributes to gain new insights into the extension and complexity of the mining infrastructure, indicating the importance of the gold-bearing raña deposits within the framework of Roman gold mining in north-west Spain.