Sergio Llana-Funez

Sergio Llana-Funez
University of Oviedo | UNIOVI · Department of Geology

PhD Geology

About

107
Publications
17,722
Reads
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921
Citations
Citations since 2016
44 Research Items
549 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Introduction
Sergio Llana-Funez currently works at the Department of Geology, University of Oviedo. Sergio does research in Structural Geology and Tectonics. Their current project is 'Structure and petrophysical properties of rocks at the base of tectonic units in the Cantabrian Zone (N Iberia).'
Additional affiliations
July 2009 - July 2016
University of Oviedo
Position
  • Rock microstructure in relation to tectonic processes: characterization of deformtion mechanisms and rheology
November 2006 - June 2009
University of Liverpool
Position
  • Feedback between physical and chemical processes during dehydration reactions
January 2004 - October 2006
The University of Manchester
Position
  • Experimental studies of deformation/metamorphism relationships
Education
September 1989 - June 1994
University of Oviedo
Field of study
  • Structural Geology

Publications

Publications (107)
Article
Full-text available
This paper presents an analysis of the main morphologies observed in the coastal cliffs of northern Spain (Asturias and Cantabria regions). The objective of this contribution is to establish a hypothesis on the origin and evolution of this rocky coast, as well as to present a detailed inventory, to characterise quantitatively and qualitatively sing...
Article
Full-text available
This paper describes the development of a GIS-based geotechnical system designed to face challenges on urban geology in a Spanish mid-sized city. Its multipurpose nature is based on a relational database that holds a wide variety of georeferenced ground data, mostly extracted from geotechnical reports or acquired during fieldwork. At present it inc...
Article
Full-text available
The cross-correlation of ambient noise records registered by seismic networks has proven to be a valuable tool to obtain new insights into the crustal structure at different scales. Based on 2 to 14 s period Rayleigh and Love dispersion data extracted from the seismic ambient noise recorded by 20 three-component broadband stations belonging to two...
Preprint
Full-text available
The cross-correlation of ambient noise records registered by seismic networks has proven to be a valuable tool to obtain new insights into the crustal structure at different scales. Based on 2- to 14-s-period Rayleigh and Love dispersion data extracted from the seismic ambient noise recorded by 20 three-component broadband stations belonging to two...
Article
Crustal roots are identified in collision chains worldwide. Frequently mirroring the summits of mountain systems, they elegantly encapsulate the concept of isostasy. The rugged topography of northern Iberia results from convergence with the European plate during the Alpine orogeny that formed the Pyrenean-Cantabrian mountain range. From east to wes...
Article
Full-text available
El análisis de imagen en muestras de roca en lámina delgada o superficie pulida permite la caracterización de los tamaños y formas de los granos o partículas que constituyen una roca. Para comprobar la eficacia de diferentes parámetros en la discriminación de granos y partículas con diferente origen y evolución en una misma roca, utiliza-mos una mu...
Article
Full-text available
Radon (Rn) constitutes a good geochemical tracer for neotec-tonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations...
Article
Radon (Rn) constitutes a good geochemical tracer for neotectonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations...
Presentation
Full-text available
The result of the analysis completed allowed the definition of: i) the parameters that best represent the grain shape variations and ii) the range of values for each parameter that are characteristic of each process, thus allowing the classification of the grain shapes. Furthermore, the analysis allowed distinguishing sub-rounded quartz grains of d...
Article
Full-text available
The Cantabrian fault (CF) is a crustal-scale structure that cuts obliquely the western North Iberian Margin (NIM) for 160 km and continues onshore transecting the Cantabrian Mountains (CM) as the Ventaniella fault (VF).Inland, the fault is aseismic, except for a 70 km segment at its southern end. Here, a gently north-dipping arrangement of earthqua...
Article
Full-text available
Mica-rich rocks (shales, slates, schists) are a major and significant component of the continental crust. They are often characterized by a strong seismic anisotropy, a key factor in the seismic interpretation of the architecture of the continental crust. Roofing slates are a group of natural rocks used in construction that must possess a continuou...
Article
Full-text available
The Cueva Huerta Natural Monument is formed by more than 20 km of karstic conduits hosted by carboniferous limestones. Here we study the geological structures that determine the orientation of the major galleries in the cave. The observations made inside the cave point to several fault slip surfaces as the main candidates in the structural control...
Article
50-day share link: https://authors.elsevier.com/a/1c74ohdGqWEzy The Esla Nappe, located in the Cantabrian Zone (Variscan Orogen, NW Iberia), has an estimated 19 km displacement to the NE accommodated in a thin (<2–3 m) shear zone (ENSZ) at least 4 km depth. Fault-rock assemblages record different deformation processes operating in the hangingwall...
Article
The upper-crustal anisotropy of the Cantabrian Mountains (North Spain) has been investigated using two independent but complementary methodologies: (a) shear-wave splitting and (b) ambient seismic noise interferometry. For this purpose, we have processed and compared seismic data from two networks with different scales and recording periods. The sh...
Article
This study analyzed potential causes of a 40% mortality rate observed in a flock of endangered Xalda sheep, indigenous to the province of Asturias in northern Spain. We found that productive and reproductive parameters of the flock were also severely affected. In order to diagnose the cause of mortality and illness in the sheep, we examined the ani...
Article
The Cantabrian margin, at the northern Iberian Peninsula, shows elevated coastal platforms extending from west to east for >200 km. These erosional surfaces are several kilometers wide, and are bounded inland by a paleoshoreline, and towards the sea by the retreating current cliff. The origin and evolution of these geomorphologic markers remains co...
Article
This study presents the first detailed analysis of ambient noise tomography in an area of the continental upper crust in the Cantabrian Mountains (NW Spain), where a confluence of crustal scale faults occurs at depth. Ambient noise data from two different seismic networks have been analyzed. In one side, a 10 short-period station network was set re...
Chapter
Full-text available
El Complejo de Cabo Ortegal es un grupo de láminas alóctonas que fueron emplazadas sobre el margen occidental de Gondwana durante la Orogenia Varisca [1]. Está formado por una Unidad Tectónica Superior, el manto de Cabo Ortegal, compuesto de rocas que registran un evento metamórfico de alta presión y alta temperatura, y una Unidad Tectónica Inferio...
Article
Full-text available
The coastal section across the Valdoviño fault exposes fault-related rocks deformed at the base of the seismogenic zone of the Iberian Variscan crust. Discrete brittle structures are superimposed over previous predominant ductile deformation fabrics in most rocks. The core of the fault contains ultramafic rocks, garnet-bearing mafic rocks, amphibol...
Article
Full-text available
Resumen: El monte Rodiles, situado en el margen oriental de la ría de Villaviciosa, conserva evidencias de ocupación histórica desde sus orígenes como castro romanizado. El asentamiento está limitado en su vertiente sur por los restos de una muralla defensiva, mientras que en la ladera nororiental existen escarpes rocosos que debieron de actuar com...
Article
Numerous cases of timing differences between glacier advances recorded in mountain environments have been documented over the last decade, usually suggesting potential age conflicts between the different dating techniques. The frequent use of a single technique to date numerically a given glacial sequence makes it difficult to address to what exten...
Article
Full-text available
Fluids released by prograde metamorphism are often invoked to explain a range of crustal processes from earthquake triggering to metasomatism. These fluids can be either trapped and overpressured or released and channelized depending on the interplay between permeability, reaction rate and compaction. Experimental data are presented, measuring perm...
Article
Bands of multi-phase mixtures with an extreme grain size reduction called ultramylonites are a common feature in shear zones from the middle crust to upper mantle conditions. Indeed, they are one of the most typical manifestations of strain localization in high-strained polymineralic rocks in the lithosphere, especially in the semi-brittle field. Y...
Conference Paper
Full-text available
The Cantabrian Zone is located at the core of the Ibero-Armorican Arc and constitutes the foreland fold-and-thrust-belt of the Variscan Orogen in NW Iberia, where several thrust nappes were emplaced during the Pennsylvanian. While its large-scale structure has been studied in detail by numerous authors, the mechanisms of emplacement of the thrust n...
Presentation
Full-text available
La falla de Ventaniella es una importante estructura (> 400 km) en el desarrollo de la Cordillera Cantábrica que, habiéndose desarrollado con anterioridad al Mioceno, presenta actividad sísmica en la actualidad. Las evidencias en superficie de la actividad tectónica remanente reciente se conservan difícilmente debido a la intensa actividad erosiva...
Data
Interactive 3D pdf with the results of our publication in the Bulletin of the Seismological Society of America (readable with Adobe Acrobat Reader). This document provide a 3D view of the seismic network deployed, the hypocenters observed and the fault intersections interpreted. The pdf allow rotate the 3D model, and make visible all or part of the...
Article
Full-text available
Intraplate seismicity in northwest (NW) Spain, an otherwise stable continental area, is dominated by low‐magnitude events and occurs both in swarms and dispersed along faults. A detailed study of one of the most active fault segments, the Ventaniella fault, has produced an accurate image of foci distribution and revealed new insights on the origin...
Article
Glacial erosion of hillslopes and stress changes induced by the transition from glacial to non‐glacial conditions exert a strong influence on slope instability and are considered among the scope of paraglacial geomorphology. Failure mechanisms and coupling between paraglacial rock‐slope failures (RSFs) and fluvial erosion are difficult to define. H...
Article
The long-term state of stress at middle and lower crustal depths can be estimated through the study of the microstructure of exhumed rocks from active and/or ancient shear zones. Constitutive equations for deformation mechanisms in experimentally deformed rocks relate differential stress to the size of recrystallized grains. Cross et al. (2017) tak...
Article
The estimation of 3D grain size distributions (GSDs) in mylonites is key to understanding the rheological properties of crystalline aggregates and to constraining dynamic recrystallization models. This paper investigates whether a common stereological method, the Saltykov method, is appropriate for the study of GSDs in mylonites. In addition, we pr...
Article
Full-text available
Control litológico y estructural de los deslizamientos en el monte Rodiles (Asturias, España) Lithological and structural control of landslides in the Rodiles Hill (Asturias, Spain) Resumen: El monte Rodiles, situado en el margen oriental de la ría de Villaviciosa, conserva evi-dencias de ocupación histórica desde sus orígenes como castro romanizad...
Article
Full-text available
Localización de la deformación en la zona de falla de Valdoviño (NO Macizo Ibérico) asistida por fluidos carbonatados ricos en Fe y el crecimiento de filosilicatos Strain localization in the Valdoviño fault zone (NW Iberian Massif) assisted by Fe-rich carbonated fluids and phyllosilicates growth Resumen: Las rocas de falla de la base sismogénica de...
Conference Paper
Full-text available
The Ventaniella fault, also called Cantabrian fault, is a crustal structure that runs NW-SE through the Cantabrian margin and Cordillera in the Northern Iberian Peninsula. The fault has a very long cartographic expression exceeding 300 km onshore and 150 offshore. The current structure acts mainly as a strike-slip with some inverse component. In so...
Conference Paper
Full-text available
The understanding of creep behaviour in rocks requires knowledge of 3D grain size distributions (GSD) that result from dynamic recrystallization processes during deformation. The methods to estimate directly the 3D grain size distribution –serial sectioning, synchrotron or X-ray-based tomography– are expensive, time-consuming and, in most cases and...
Article
Full-text available
High-grade, highly deformed gneisses crop out continuously along the Masanteo peninsula and constitute the upper part of the lower crustal section in the Cabo Ortegal nappe (NW Spain). The rock sequence formed by migmatitic quartzo-feldspathic (qz-fsp) gneisses and mafic rocks records the early Ordovician (ca. 480-488ĝ€Ma) injection of felsic diori...
Article
Full-text available
High-grade highly deformed gneisses crop out continuously along the Masanteo peninsula in the Cabo Ortegal nappe (NW Spain). The rock sequence formed by quartzo-feldspathic gneisses and mafic rocks records two partial melting events: during the Early Ordovician (ca. 480–488 Ma.), at the base of the Qz-Fsp gneisses, and immediately after eclogizatio...
Article
Full-text available
Th/U values in zircon are commonly used to discriminate between metamorphic (Th/U < 0.1) and magmatic (Th/U > 0.1) origin for zircon overgrowths. We test this hypothesis in the San Ciprián massif, a late orogenic granitic intrusion in the hinterland of the Variscan orogeny. Zircon grains from this granite have cores with inherited Ediacaran ages an...
Chapter
Full-text available
The Malpica Lamego Ductile Shear Zone (MLDSZ) is a major crustal-scale tectonic structure, with a complex tectonic history since pre-Variscan to Variscan orogeny, which extends for at least 275 km from its northernmost exposure (Malpica, Spain) to its southern tip (Lamego, Portugal). It is characterized by the development of a wide deformation zone...
Article
The distribution of seismicity at the western end of the Cantabrian mountain range (NW Iberia), reflecting current crustal dynamics, is investigated integrating seismically active structures, long-term structures, and the topographic features at the surface. The thickness of the seismogenic zone within the continental crust is established in 20 km....
Article
Full-text available
Paleopiezometry and paleowattmetry studies are essential to validate models of lithospheric deformation and therefore increasingly common in structural geology. These studies require a single measure of dynamically recrystallized grain size in natural mylonites to estimate the magnitude of differential paleostress (or the rate of mechanical work)....
Article
Full-text available
The Vivero fault is crustal-scale extensional shear zone parallel to the Variscan orogen in the Iberian massif belt with an associated dip-slip movement toward the hinterland. To constrain the timing of the extension accommodated by this structure, we performed zircon U–Pb LA-ICP-MS geochronology in several deformed plutons: some of them emplaced s...
Article
Paleopiezometry and paleowattometry studies, required to validate models of lithospheric deformation, are increasingly common in structural geology. These studies require a numeric parameter to characterize and compare the dynamically recrystallized grain size of natural mylonites with those obtained in rocks deformed under controlled conditions in...
Article
Specimens of Solnhofen limestone were deformed under conditions where calcite deforms plastically using four experimental configurations: extension, torsion, direct shear and axisymmetric shortening. All experiments were run on dry specimens at the same temperature (600 ºC), confining pressure (200 MPa) and comparable strain rates (c. 10-4 s-1). Th...
Article
Full-text available
The collection of research papers in this volume provides an overview of current trends in the study of deformation structures and deformation processes in rocks from the continental crust. The volume has been divided into three sections to reflect the current interest in structures and processes: shear zones and folds; the interactions between mag...
Conference Paper
Full-text available
The Valdoviño Fault is a subvertical left-lateral strike-slip fault that exceeding a hundred kms in length formed in the late stages of the Variscan orogeny in NW Iberia. The fault cuts through the pile of allochthonous thrust sheets that conform the suture zone of the orogen and constitutes the eastern boundary of one of them, the Ordenes complex....
Data
We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comp...
Article
Full-text available
The lithostratigraphic sequence of the Upper Allochthon of the Cabo Ortegal complex in northwestern Spain provides an excellent analog for the direct study of petrophysical properties of the continental Moho transition. The various lithologies present were sampled for velocity measurements on minicores and determination of seismic velocities throug...
Conference Paper
The effects on mechanical properties of rocks consequence of the progress of mineral reactions in rocks are particularly accesible and relatively easy to monitor in laboratory experimentation in the case of dehydration reactions because of the bulk volume changes involved as well as in the solid fraction. Hydrated minerals are primary rock-forming...
Conference Paper
Full-text available
La sismicidad de la corteza continental se nuclea preferentemente en la corteza superior, donde el régimen de deformación predominante es friccional. El espesor de la zona sismogénica depende sobre todo de la composición litológica, la temperatura y la presencia y presión de fluidos en el espacio poroso. La base de la zona sismogénica, que se defin...
Conference Paper
El nivel de erosión actual en las zonas internas del Orógeno Varisco en el NO de la Península Ibérica permite la exposición en superficie de estructuras formadas a profundidades de la corteza-media. Desde el punto de vista mecánico, este nivel cortical representa la transición entre una corteza superior en la que dominan los procesos friccionales,...
Conference Paper
Full-text available
Metamorphic reactions, deformation mechanism and chemical changes during mylonitization and ultramylonitization of granite affected by a crustal-scale shear zone are investigated using microstructural observations and quantitative analysis. The Vivero Fault (VF) is a large extensional shear zone (>140Km) in NW of Iberia that follows the main Varisc...
Article
Full-text available
We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comp...
Article
Full-text available
Pressure is a key control on the progress of metamorphic reactions. When fluids are present in rocks, the fluid pressure is commonly different to the load supported by the solid framework. Here, we show experimentally that, when the two pressures are varied independently, fluid pressure exerts the dominant control on reaction rate, even when the ro...
Article
Full-text available
The Malpica-Lamego Line is a major crustal-scale shear zone, at least 275 km long, that runs parallel to the grain of the Variscan Orogen in Western Iberia. Based on the offset of the rock sequence on either side of the shear zone a substantial displacement, in excess of 10 km vertical and horizontal, was inferred. Its orientation with respect to t...
Article
Full-text available
We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comp...
Article
Full-text available
Dehydration reactions have important effects on fluid flow, pore pressure and brittle failure in the Earth. The rates and mechanisms of reaction are relevant to understanding those effects. The microstructures of a set of samples containing bassanite and gypsum from dehydration experiments on Volterra gypsum have been analysed by conventional trans...