The Central Iberian Mountain Range a Key Asset to the Deformation Mechanisms of Iberia

This project aims do an integrated multidisciplinary, lithsopheric model across the Central System of Iberia, from the Tajo Basin, across the mountain chain till the Duero Basin. One of the most relevant topographic features of the Iberian Peninsula is the relatively high elevation of its interior and, in particular of the Central System. The Central meseta (plateau) is characterized by an average altitude of 600-700 m and, is actively increasing its elevation, being one of the highest of all the European continent. By obtaining the proposed geologic and geophysical model we aim to provide unique new constraints and contribute to the understanding of the topography and the causes of its changes. Changes in topography reflect a combination of the deep and Surface processes and ints interaction with the crust. It is recognize that critical players in the resulting response are the crustal thickness, nature (lithologies) physical properties of the crust and upper mantle and its internal architecture. The proposal includes: a multidisciplinary study of the surface, including surface geology, geophysics (potential field and seismics).

Integrated geological and geophysical analysis of the linkage between transverse zones and inherited basement structures in foreland thrust-and-fold belts: the Taiwan example

The baseline assumption being made in this proposal is that heterogeneities (in the form of pre-exisiting faults, zones of sedimentary facies change etc.) in a continental margin that forms the underthrusting plate of a thrust-and-fold belt plays an important role in the development of transverse structures in the upper plate (the thrust-and-fold belt). The hypothesis to be tested is that pre-exisitng faults along the continental margin of southeast Eurasia are being reactivated forming transverse structures in the Taiwan thrust-and-fold belt. The corollary to this hypothesis is that there is a link between these transverse structures and re-activated basement faults during early stages of collision and this therefore affects not only the structure but also the seismicity and the landscape evolution. The main objective of this research is to use an integrated data set consisting of field geology, geophysical, geodetic, and potential field data to further the understanding of the importance of fault reactivation in the formation of transverse zones, to study how the linkage and displacement between these transverse zones and thrusts works, and what the effect is on transient features such as the stress field (calculated from earthquake focal mechanisms), seismicity, and topography. Taiwan is a particularly good place to investigate this process because it is possible to trace the main features of the margin (fault systems, margin morphology) into the undeformed and weakly deformed foreland and, we think, farther into the thrust-and-fold belt itself. Furthermore, the whole (pre-existing fault systems entering the deformation, faults forming the thrust-and-fold belt, and the sedimentary system of the foreland basin) is active, meaning that the transverse structures can be illuminated at depth by earthquakes and, therefore, high-resolution seismic tomography. Taiwan, then, provides an exceptional setting for the study of the causal relationships between the formation of transverse structures in a thrust-and-fold belt and a margin’s morphology and heterogeneities.

Seismic Ambient Noise Imaging and Monitoring of Shallow Structures

This proposal is focused on the characterization of the structure and its eventual temporal variations at the uppermost crust based on the analysis of the background seismic vibrations (ambient noise) and using a dense network of seismic nodes providing unprecedented spatial resolution. As the amount and characteristics of the seismic ambient noise is dependent on anthropogenic factors, it is important to document the applicability of ambient noise methods in zones with low and high levels of anthropogenic activity. In the first case, we have selected a relatively undisturbed environment, the Cerdanya Neogene sedimentary basin in the eastern Pyrenees. The seismic nodes array that will be deployed in the basin is expected to provide detailed 3D images of the structure of the uppermost crust levels. In the second case, we will focus on areas as active mining sites and the city of Barcelona. An important aspect of the proposal refers to scientific dissemination, as we seek to involve educational centers in the city to participate in the project by offering their premises to install the instruments. On exchange, students in those centers will be trained in the use of seismic instruments and the first analysis of the data, in an attempt to catch their interest on seismology and Earth Sciences in general.

Geochronology and petrogenesis of the Holocene volcanism of El Hierro,Canary Islands

El Hierro is, together with La Palma, the youngest island of the Canarian Archipelago. Both islands are in the shield stage of their volcanic growth, which implies a high volcanic activity during the Holocene period. The submarine eruption occurred in October 2011 in the SSE rift of El Hierro evidenced the active volcanic character of the island. Even so, despite the numerous scientific works published following the submarine eruption (most of them centered to understand such volcanic event), there is still a lack of precise knowledge about the Holocene subaerial volcanism of this island. The LAJIAL Project focuses on solving this knowledge gap in order to verify the hypothesis that the Holocene volcanism in El Hierro follows a pattern with quiescence periods of 1000 to 2000 years between eruptive periods. The research of the most recent volcanism of the island, the last 11,700 years of the Holocene, covers a long enough period whereas it is close to the present day. Thus, this period is the best to model the eruptive processes that will allow us to evaluate the future scenarios of the eruptive dynamics in El Hierro. The Project LAJIAL combines methodologies of geological mapping, geomorphology, GIS, chronostratigraphy, paleomagnetism, petrology and geochemistry to solve the Holocene eruptive recurrence rate in El Hierro, and to constrain the rift model of intraplate ocean volcanic islands.

Geodynamics of the Central Alpine Mediterranean Orogenic System: Mantle characterization and vertical motions

The Alpine Mediterranean Orogenic System encompasses a set of tectonic domains linked to the closure of the Tethyan Ocean during the Late Cretaceous-Cenozoic, characterized by an enigmatic alternation of fold-and-thrust belts separated by oceanic domains. This alternation and the closure of the Tethys itself are the consequence of the onset of counter-clockwise rotation and northward motion of the Nubia plate against Eurasia that initiated multiple subductions of the Tethyan oceanic realms around 83.5 Ma. Lateral changes in the subduction polarity in the Central Mediterranean region gave rise to three orogenic belts (Apennines, Dinarides and Carpathians) separated by two extensional back-arc basins (Tyrrhenian and Pannonian) and the Adriatic microplate. This complex segmented subduction system and the corresponding roll-back of the individual slabs generated an active return mantle flow with mantle-sourced volcanism, thrust-belts and deep depocentres. However, despite the large amount of scientific literature about the age, geometry, size and location of these oceanic domains, the underlaying geodynamic mechanisms as well as the interconnections between the resulting orogenic belt/back-arc basins remain under discussion. In this project we aim to bring new light on how the Central Alpine Mediterranean Orogenic System has been shaped by the Africa-Eurasia convergence and on the triggering mechanisms that accommodated this convergence. We also aim at clarifying the impact of these events on the surface mass redistribution and the conditions under which the Tyrrhenian, Adriatic and Pannonian sedimentary basins (main repositories of natural resources in the region). For this we will perform numerical modeling on a transect crossing the Central Mediterranean through the Tyrrhenian back-arc oceanic basin, the Apennines fold belt, the doubly subducting Adriatic Sea, the Dinarides fold belt, the Pannonian back-arc continental basin and the Carpathians fold belt to the SW of the stable Eurasia plate. Our methods combine geophysical, structural and petrological data to infer the crustal and upper mantle structure down to 400 km depth. We will apply both static (present-day) lithospheric structure and geodynamic modelling to account for mantle seismic velocities, surface heat flow measurements, elevation, gravity and geoid anomalies, and sedimentation/erosion data. We will obtain a new balanced geological cross-section of the lithosphere consistent with plate reconstructions and geophysical data.

VOLCLIMA

The dimate of the last millennia and the ¡nfluence of external forcings (e.g. anthropogenic gas emissions) have received great attenlion over the past decades. Thus, the connection between volcanism, climate change and modes ofclimate variability has been a quite visited topic. Whereas the impact of volcaníc eruptions on global climate has been observecf and is widely accepted, there is still an open discussíon about the effect oí volcanic forcing on the individual climate modes, ¡.e. climate patterns with Ídentifjable patterns, specific regional effects, and often with oscillatory behaviour (e.g. El Nifío/a Southern Oscillation ENSO). We propase in VOLCLIMA that the volcanic signa! of large Southem HemJsphere (SH) volcanoes cannot pass unnoticed to the different climate system elements. We consider that, as it is largely demonstrated that happens ¡n the Northem Hemisphere, large eruptions occumng in the SH, including high-latitude ones, may significantly afféct the hemispheric climate in terms of heat and moisture balances, affecting Antarctic ice retreat/accumuiaiioh and atmospheric circulation patterns and modes such as the Antarctic Osciilation, the Soulhem Annular Mode (SAM) and indirectly, the current or forthcoming ENSO events. If our hypolhesis results correct, we could shed some líghí on the cause-effect link of volcanic eruptions and individual climatic modes. The methodological approach consists of obtaining three 7.5 m long marine sediment cores using the pistón core of the R/V Hesperides at Deception islands (Antarctica) interior bay, Port Foster. Deception Island ¡s a very active volcano with over 20 considerably large eruptions in the lastmillennia. The correiation ofthe evolution of volcanic eruptions and climate fluctuations will permit to assess the short» and long -íerm interactions behA/een both forcings and to determine their impact on the regional climate, as well as on the main climate modes (SAM, ENSO) and water currents.