Characterizing the source of the Eastern Galicia Magnetic Anomaly (NW Spain): the role of extension in the origin of magnetization at the Central Iberian Arc.

Tectonics ◽  
2021 ◽  
Author(s):  
P. Ayarza ◽  
J.J. Villalaín ◽  
J.R. Martínez‐Catalán ◽  
Álvarez Lobato, F. ◽  
Durán Oreja, M. ◽  
...  
2020 ◽  
Author(s):  
Puy Ayarza ◽  
Juan José Villalaín ◽  
Jose Ramón Martínez Catalán ◽  
Fernando Alvarez Lobato ◽  
Manuela Durán Oreja ◽  
...  

<p><span lang="EN-US">The Eastern Galicia Magnetic Anomaly (EGMA) is one of the most conspicuous and, definitively, the best studied of all the magnetic anomalies in the Central Iberian Arc (CIA). This is probably due to its location, on the thoroughly researched Lugo-Sanabria gneiss dome and to the unique fact that its source rocks crop out in the Xistral Tectonic Window. Multiple studies and models of this anomaly have been carried out in the last 25 years and still, new results keep on shedding more light on its understanding. Rock magnetic analyses, natural remanent magnetization, anisotropy of the magnetic susceptibility and stable isotopes geochemistry carried out on the rocks that produce this anomaly have provided new insights on the processes that led to magnetization and on its age. Results suggest that magnetization of source rocks is a consequence of the increase in oxygen fugacity underwent by metamorphic and magmatic rocks affected by late-Variscan extensional tectonics. Extensional detachments were the pathways that allowed the entrance of fluids that led to syn-tectonic crystallization of magnetite and hematite in S-Type granites. Accordingly, magnetization is not really linked to primary lithologies but mostly to extensional structures. This process took place in the late Carboniferous to earliest Permian, during the Kiaman reverse superchron. Natural remanent magnetization exhibited by hematite-bearing samples confirms the age of the magnetization and adds complexity to the interpretation of the EGMA, where remanence has been often largely ignored or underestimated. Understanding the origin of the EGMA contributes to the interpretation of other anomalies existing in the CIA, also located on thermal domes. Furthermore, it provides new hints to interpret magnetic anomalies located in extensional tectonic contexts worldwide</span></p>


2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Paloma Bescansa ◽  
Iñigo Virto ◽  
Oihane Fernández-Ugalde ◽  
María José Imaz ◽  
Alberto Enrique

The behaviour of earthworms, their role in organic matter incorporation into the soil, and the influence of aridity in such processes in arid and semiarid regions have scarcely been studied. In this study, physico-chemical analyses of the casts and the surrounding no-till agricultural soils of three experimental sites representing an aridity gradient in Navarre (NW Spain) were done. The casts were formed by the activity of the only anecic species,Scherotheca gigas(Dugès, 1828), ubiquitous in no-till soils in this region. We observed a significant depletion of clay and higher concentration of total organic C and labile C in the form of particulate organic matter (POM) in the casts as compared to the surrounding soil, suggesting selective ingestion of soil byS. gigas. This, together with the observation of increased concentration in POM with increasing aridity, suggests a major role of this species in the observed progressive gains of organic C stocks in no-till soils in the region.


2022 ◽  
pp. 1-16
Author(s):  
Elena De Uña-Álvarez ◽  
Montserrat Villarino-Pérez

Inland territories hold a great diversity of ecocultural resources, increasingly constituted in tourist products for local development. Their role in improving the socioeconomic conditions and wellness of local communities, as well as in promoting tourism and sustainability, depends on the involvement of public and private actors. The relationships and the collaboration of local actors are essential in that regard. The study of aforementioned processes takes place in the inland territory of Galicia (NW Spain). The methodology of research relied on in-depth interviews. Due to the key role of the local actors, the interviews focused on their professional and life experiences. The analysis of the answers establishes the definition and the appraisal of the main resources, attached to territorial identity, and highlights the engagement and involvement of the actors in the territorial dynamics that foster the promotion of the ecocultural resources for tourism.


2013 ◽  
Vol 44 (1-4) ◽  
pp. 397-403
Author(s):  
M. Luz Rodríguez-Blanco ◽  
M. Mercedes Taboada-Castro ◽  
Laura Palleiro ◽  
Fátima Soto ◽  
M. Teresa Taboada-Castro

2015 ◽  
Vol 5 (3) ◽  
pp. 122-129 ◽  
Author(s):  
Трещевская ◽  
Ella Treshchevskaya ◽  
Тихонова ◽  
Elena Tikhonova

The analysis of man of organic subterranean and ground matter was performed among av-erage model trees. The increase in the mass of roots and ground biomass of the two layers tech-nozem with thick fertile layer was detected. In technogenic dump landscapes special reclamation importance is attached to green parts of plants. Forest protects the surface of slopes from destruc-tion, increases the concentration of nitrogen and ash elements in the fertile layer. The role of plantations in the transformation of the waste lands increase when mass of green assimilative organs increases. The fast growth of the trunk and larger branches of plants begins in 6-9 years.


2011 ◽  
Vol 115 (11) ◽  
pp. 4851-4855 ◽  
Author(s):  
M. Viswanathan ◽  
H. H. Hsieh ◽  
H.-J. Lin ◽  
C. T. Chen ◽  
P. S. Anil Kumar

Web Ecology ◽  
2001 ◽  
Vol 2 (1) ◽  
pp. 22-31 ◽  
Author(s):  
L. Valbuena ◽  
R. Nuñez ◽  
L. Calvo

Abstract. In the Cantabrian area (northwest Spain) Pinus stands occupy many of the original shrub communities that have been considered unproductive. These Pinus stands represent the vegetation which is most affected by fire. Regeneration after fire may occur in different ways: by resprouting or by germination or both. Germination was the only regeneration mechanism in Pinus species that appeared in these areas. The aim of this study is to determine the role of the soil seed bank in regeneration in this type of ecosystem. In order to carry out the study, three communities dominated by Pinus sylvestris which had suffered wildfires were chosen. In each of the three experimental sites of Pinus sylvestris stands the seed bank composition and above-ground vegetation were studied. The results allowed three species groups in the seed bank to be differentiated: those favoured by fire, amongst which some hardseeds, mainly belonging to Cistaceae and Leguminosae, were found; another group formed by outsider or opportunist species from outside the community and which used anemochory as their main dispersion mechanism; and the third group formed by those negatively affected, amongst which were species using vegetative resprout as the main regeneration mechanism. The species of greatest quantitative importance in the seed bank was Erica australis. In general, anemochorous species were predominant in the soil seed bank. During the first stages of succession chamaephytes were dominant and in the two years after fire therophytes were. No great similarity was observed between the bank composition and field vegetation from a qualitative viewpoint, due to differences in the presence of seeds of outsider plants in the bank and to the significance of the resprouting species in the field.


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