Role of the Adria plate structural heterogeneities on the dynamics of the Central-Western Mediterranean region

2021 ◽  
Author(s):  
Rosalia Lo Bue ◽  
Manuele Faccenda ◽  
Jianfeng Yang
Keyword(s):  
Steady State ◽  
Continental Margin ◽  
Mediterranean Region ◽  
Subduction Zones ◽  
Seismic Anisotropy ◽  
Western Mediterranean ◽  
Mantle Flow ◽  
Crystal Preferred Orientation ◽  
The Mediterranean ◽  
Structural Heterogeneities

<p>In the geodynamic context of the slow Africa-Europe plates convergence, the Central-Western Mediterranean region has been involved in a complex subduction process, which in the last 30 Myr was characterized by the rapid retreat of the Ionian slab, the opening of back-arc extensional basins (i.e., Liguro-Provençal, Algerian, Alboran, and Tyrrhenian basins) and episodes of slab lateral tearing, segmentation and break-off.  A proper modelling of 3-D mantle flow evolution beneath the Mediterranean could provide important clarifications about the complex mantle dynamics of this region and help us understanding the interaction between surface tectono-magmatic processes and mantle convection patterns. </p><p>The mantle flow and its relations with plate horizontal and vertical motions can be determined by measuring seismic anisotropy generated by strain-induced lattice/crystal preferred orientation (LPO/CPO) of intrinsically anisotropic minerals. Seismic anisotropy is widespread in the Mediterranean and it shows an intricate pattern that likely has some relations with the recent (20-30 Myr) behavior of subducting slabs. The extrapolation of the mantle flow from seismic anisotropy is neither simple nor always warranted, especially at subduction zones where complex and non-steady-state 3D flow patterns may establish.  A promising approach, which helps reducing the number of plausible models that can explain a given anisotropy dataset, is to compare seismic measurements with predictions of numerical and experimental flow models (Long et al.,2007). Recently, Faccenda and Capitanio (2013) and Faccenda (2014) have extended this methodology to account for the non-steady state evolution typical of many subduction zones, yielding mantle fabrics that are physically consistent with the deformation history.</p><p>In this study, we apply a similar modelling approach to the complex Central-Western Mediterranean convergent margin. We use the wealth of observations from the Mediterranean region available in the literature to design and calibrate 3D thermo-mechanical subduction modelling. We test different initial configurations defined at 30 Ma according to the paleogeographic and tectonic reconstructions derived from (Lucente and Speranza, 2001; Carminati et al., 2012; van Hinsbergen et al., 2014) in order to optimize the fit between predicted and observed slabs position and obtain a final model configuration resembling the present-day surface and deeper structures.</p><p>In particular, here we want to evaluate the influence on rollback rates, trench shape and the occurrence and timing of slab tears (Mason et al., 2010) of structural heterogeneities within the Adria plate as proposed by (Lucente and Speranza, 2001). In all models, subduction migrates south-eastward driven by the subducting oceanic lithosphere, and slab lateral tearing or break-off occurs when a continental margin enters the trench. More importantly, we show that the presence of a stiffer continental promontory in central Adria together with a thinned continental margin in the Umbria-Marche region plays a fundamental role on (i) the development of a slab window below the Central Apennines, (ii) the retreat of the Northern Apenninic trench till the Adriatic Sea, and (iii) the retreat of the Ionian slab till the present-day position.</p>

V.—Rodents from the Pleistocene of the Western Mediterranean Region

1905 ◽  
Vol 2 (10) ◽  
pp. 462-467 ◽  
Author(s):  
C. I. Forsyth Major
Keyword(s):  
Geographical Distribution ◽  
Mediterranean Region ◽  
Western Mediterranean ◽  
Ice Age ◽  
Cold Regions ◽  
The Mediterranean

In a former publication I have dealt with the anatomy of Prolagus sardus (Wagn.), from the Sardinian and Corsican Pleistocene, in comparison with that of its Tertiary relatives. The following pages deal with the geographical distribution of Pleistocene Prolagus and its bearing on more general questions.When Ouvier discovered, in the ossiferous breccia of Corsica, remains of a ‘Lagomys,’ which he believed to be closely related to the Siberian Lagomys alpinus, he also suggested other analogies between the faunas of the two regions—Siberia and Corsica (as well as Sardinia), and commented upon the supposed relationship between the insular Mouflon and the Siberian Argali. Similar views were expressed by B. Wagner.Pumpelly, Loeard, and Lortet sought to establish a connection between a supposed Corsioan ‘ice-age,’ as attested by the trace of ancient glaciers, and the former existence in the island of a supposed inhabitant of cold regions, the Lagomys corsicanus. Hensel had, however, shown before, in 1856, that the affinities of Lagomys sardus from the Sardinian bone breccia are not with the recent Lagomys (Ogotona), but with a Miocene type, for which he proposed the generic name Myolagus (antedated by Prolagus, Pormel). He was in consequence inclined to assume a Tertiary age for the breccias in which the Prolagus occurred (and, indeed, for the whole of the Mediterranean bone breccias). A similar view has again been brought forward of late years.I myself pointed out (1) that the Corsican Lagomys likewise belonged to the genus Prolagus, as indeed had already been suspected by Hensel from his inspection of Cuvier's figures; (2) that the Tertiary age of the Corsican and Sardinian breccias could not be upheld, above all, because the mollusca occurring in them, as Loeard bad shown to be the case in the ossiferous breccia of Toga, near Bastia, are still living in the neighbourhood.

Subduction Orogeny and the Late Cenozoic Evolution of the Mediterranean Arcs

2018 ◽  
Vol 46 (1) ◽  
pp. 261-289 ◽  
Author(s):  
Leigh Royden ◽  
Claudio Faccenna
Keyword(s):  
Convergence Rate ◽  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Tectonic Setting ◽  
Western Mediterranean ◽  
Driving Mechanism ◽  
Late Cenozoic ◽  
Central Mediterranean ◽  
The Mediterranean ◽  
Collisional Orogens

The Late Cenozoic tectonic evolution of the Mediterranean region, which is sandwiched between the converging African and European continents, is dominated by the process of subduction orogeny. Subduction orogeny occurs where localized subduction, driven by negative slab buoyancy, is more rapid than the convergence rate of the bounding plates; it is commonly developed in zones of early or incomplete continental collision. Subduction orogens can be distinguished from collisional orogens on the basis of driving mechanism, tectonic setting, and geologic expression. Three distinct Late Cenozoic subduction orogens can be identified in the Mediterranean region, making up the Western Mediterranean (Apennine, external Betic, Maghebride, Rif), Central Mediterranean (Carpathian), and Eastern Mediterranean (southern Dinaride, external Hellenide, external Tauride) Arcs. The Late Cenozoic evolution of these orogens, described in this article, is best understood in light of the processes that govern subduction orogeny and depends strongly on the buoyancy of the locally subducting lithosphere; it is thus strongly related to paleogeography. Because the slow (4–10 mm/yr) convergence rate between Africa and Eurasia has preserved the early collisional environment, and associated tectonism, for tens of millions of years, the Mediterranean region provides an excellent opportunity to elucidate the dynamic and kinematic processes of subduction orogeny and to better understand how these processes operate in other orogenic systems.

Interpretation tectono-physique des caracteres structuraux et paleogeographiques de la Mediterranee occidentale

1951 ◽  
Vol S6-I (8) ◽  
pp. 735-762 ◽  
Author(s):  
Louis Glangeaud
Keyword(s):  
Mediterranean Region ◽  
Middle Eocene ◽  
Structural Evolution ◽  
Western Mediterranean ◽  
Physical Processes ◽  
Upper Oligocene ◽  
Single Category ◽  
The Mediterranean ◽  
Autonomous Evolution

Abstract The structural evolution of the western Mediterranean region cannot be explained on the basis of any single category of physical processes, such as continental migration or subcrustal convection currents, but by action of several processes, whose individual roles varied with time and place. Four stages are distinguished in the structural evolution--disjunction leading to separation of the "Mediterranean mosaic" into several fragments at the close of the Paleozoic and the beginning of the Mesozoic; monoliminary (autonomous) evolution of the border of certain of these fragments during the Mesozoic; diastrophic activity in middle Eocene to upper Oligocene time, during which the blocks of the mosaic were squeezed between Europe and Africa; Miocene to Plio-Quaternary phases of relaxation, accompanied by isostatic readjustment and subcrustal flow.

scholarly journals Precipitation climatology over Mediterranean Basin from ten years of TRMM measurements

2008 ◽  
Vol 17 ◽  
pp. 87-91 ◽  
Author(s):  
A. V. Mehta ◽  
S. Yang
Keyword(s):  
Mediterranean Sea ◽  
Rainy Season ◽  
Mediterranean Region ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Tropical Rainfall Measuring Mission ◽  
Western Mediterranean ◽  
Sea Temperature ◽  
Maximum Rainfall ◽  
The Mediterranean

Abstract. Climatological features of mesoscale rain activities over the Mediterranean region between 5° W–40° E and 28° N–48° N are examined using the Tropical Rainfall Measuring Mission (TRMM) 3B42 and 2A25 rain products. The 3B42 rainrates at 3-hourly, 0.25°×0.25° spatial resolution for the last 10 years (January 1998 to July 2007) are used to form and analyze the 5-day mean and monthly mean climatology of rainfall. Results show considerable regional and seasonal differences of rainfall over the Mediterranean Region. The maximum rainfall (3–5 mm day−1) occurs over the mountain regions of Europe, while the minimum rainfall is observed over North Africa (~0.5 mm day−1). The main rainy season over the Mediterranean Sea extends from October to March, with maximum rainfall occurring during November–December. Over the Mediterranean Sea, an average rainrate of ~1–2 mm day−1 is observed, but during the rainy season there is 20% larger rainfall over the western Mediterranean Sea than that over the eastern Mediterranean Sea. During the rainy season, mesoscale rain systems generally propagate from west to east and from north to south over the Mediterranean region, likely to be associated with Mediterranean cyclonic disturbances resulting from interactions among large-scale circulation, orography, and land-sea temperature contrast.

A Sicilian–Cretan biogeographical disjunction in the land snail genus Cornu (Gastropoda: Helicidae)

2020 ◽  
Author(s):  
Bernhard Hausdorf ◽  
Sonja Bamberger ◽  
Frank Walther
Keyword(s):  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Molecular Genetic ◽  
Divergence Time ◽  
Eastern Mediterranean Region ◽  
Land Snail ◽  
Western Mediterranean ◽  
Long Distance ◽  
Western Africa ◽  
The Mediterranean

Abstract We report an unusual biogeographical disjunction between the western and the eastern Mediterranean region. Cornu (Gastropoda: Helicidae) is a western Mediterranean land snail genus. It includes Cornu (Cornu) aspersum, which originated in north-western Africa and was distributed by humans for food or accidentally, first throughout the Mediterranean region and, subsequently, to all continents except Antarctica. It also includes three species belonging to the subgenus Erctella, which are all endemic to Sicily. We discovered a new species of Cornu on the Greek island of Crete. The morphological and molecular genetic analyses showed that the species from Crete is a disjunct representative of the subgenus Erctella. We hypothesize that the disjunction originated by a long-distance dispersal event of the ancestors of the Cretan species from Sicily by birds or by sea currents, perhaps facilitated by a tsunami or a similar event. The Cretan lineage separated from the Sicilian species in the Late Miocene or Early Pliocene. This divergence time is compatible with the hypothesis that the ancestor of Cornu cretense sp. nov. was washed from Sicily to Crete by the Zanclean flood that refilled the Mediterranean basin after it had dried up during the Messinian salinity crisis.

The Climate System

2009 ◽  
Author(s):  
Andrew Harding ◽  
Jean Palutikof
Keyword(s):  
High Pressure ◽  
Mediterranean Region ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Subtropical High ◽  
Westerly Wind ◽  
The West ◽  
The North ◽  
Dry Conditions ◽  
The Mediterranean

The Mediterranean region has a highly distinctive climate due to its position between 30 and 45°N to the west of the Euro-Asian landmass. With respect to the global atmospheric system, it lies between subtropical high pressure systems to the south, and westerly wind belts to the north. In winter, as these systems move equatorward, the Mediterranean basin lies under the influence of, and is exposed to, the westerly wind belt, and the weather is wet and mild. In the summer, as shown in Figure 3.1, the Mediterranean lies under subtropical high pressure systems, and conditions are hot and dry, with an absolute drought that may persist for more than two or three months in drier regions. Climates such as this are relatively rare, and the Mediterranean shares its winter wet/summer dry conditions with locations as distant as central Chile, the southern tip of Cape Province in South Africa, southwest Australia in the Southern Hemisphere, and central California in the Northern Hemisphere. All have in common their mid-latitude position, between subtropical high pressure systems and westerly wind belts. They all lie on the westerly side of continents so that, in winter, when the westerly wind belts dominate over their locations, they are exposed to rain-bearing winds. In the Köppen classification (Köppen 1936), these climates are known as Mediterranean (Type Cs, which is subdivided in turn into maritime Csb and continental Csa). The influence of the Mediterranean Sea means that the Mediterranean-type climate of the region extends much further into the continental landmass than elsewhere, and is not restricted to a narrow ocean-facing strip. Nevertheless, within the Mediterranean region climate is modified by position and topographic influences can be important. The proximity of the western Mediterranean to the Atlantic Ocean gives its climate a maritime flavour, with higher rainfall and milder temperatures throughout the year. The eastern Mediterranean lies closer to the truly continental influences of central Europe and Asia. Its climate is drier, and temperatures are hotter in summer and colder in winter than in the west. Annual rainfall is typically around 750 mm in Rome, but only around 400 mm in Athens.

Twin induced attenuation of seismic anisotropy in lawsonite blueschist

2021 ◽  
Author(s):  
Seungsoon Choi ◽  
Olivier Fabbri ◽  
Gültekin Topuz ◽  
Aral Okay ◽  
Haemyeong Jung
Keyword(s):  
Electron Microscope ◽  
Oceanic Crust ◽  
Subduction Zones ◽  
Seismic Anisotropy ◽  
Elastic Anisotropy ◽  
S Wave ◽  
Electron Backscattered Diffraction ◽  
Crystal Preferred Orientation ◽  
Fabric Strength ◽  
Scanning Electron

<p>Lawsonite is an important mineral to understand seismic anisotropy in subducting oceanic crust because of its large elastic anisotropy and prevalence in cold subduction zones. However, there is a lack of knowledge on how lawsonite twinning affects seismic anisotropy despite previous reports showing the existence of twins in lawsonite. We thus investigated the effect of twins in lawsonite on crystal preferred orientation (CPO), fabric strength, and seismic anisotropy of lawsonite using the lawsonite blueschists from Alpine Corsica (France) and Sivrihisar Massif (Turkey). CPOs of minerals were measured by using the electron backscattered diffraction (EBSD) facility attached to scanning electron microscope. The EBSD analyses of lawsonite revealed that {110} twin in lawsonite is developed and [001] axes are strongly aligned subnormal to the foliation and both [100] and [010] axes are aligned subparallel to the foliation. It is found that the existence of twins in lawsonite could induce a large attenuation of seismic anisotropy, especially for the maximum S-wave anisotropy up to 18.4 % in lawsonite and 24.3 % in the whole rocks. Therefore, lawsonite twinning needs to be considered in the interpretation of seismic anisotropy in the subducting oceanic crust in cold subduction zones.</p>

A revised typification of Jasione corymbosa and J. glabra (Campanulaceae) from the Western Mediterranean area

Phytotaxa ◽  
2015 ◽  
Vol 233 (1) ◽  
pp. 94 ◽  
Author(s):  
PEDRO PABLO FERRER-GALLEGO ◽  
Ángel Romo ◽  
Roberto Roselló ◽  
Emilio Laguna ◽  
Juan Bautista Peris
Keyword(s):  
Iberian Peninsula ◽  
Mediterranean Region ◽  
Coastal Dunes ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Ecological Niches ◽  
Wide Range ◽  
The Mediterranean ◽  
High Degree ◽  
Maximum Expression

The genus Jasione Linnaeus (1753: 163) (Campanulaceae Juss.) is represented by ca. 16 species distributed throughout Europe and the Mediterranean Region, from coastal dunes to alpine zones, and growing on a wide variety of substrates as well (Sales & Hedge 2001b). The genus shows a high degree of polymorphism, which can be partially caused by its representation accross a wide range of ecological niches. This variability reaches its maximum expression within the Iberian Peninsula (Bokhari & Sales 2001).

scholarly journals The sequence of heavy precipitation and flash flooding of 12 and 13 September 2019 in eastern Spain. Part I: Mesoscale diagnostic and sensitivity analysis of precipitation

2021 ◽  
Author(s):  
Alejandro Hermoso ◽  
Victor Homar ◽  
Arnau Amengual
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Mediterranean Region ◽  
Heavy Precipitation ◽  
Western Mediterranean ◽  
Moisture Distribution ◽  
Flash Flooding ◽  
The Mediterranean

AbstractThe Mediterranean region is frequently affected by heavy precipitation episodes and subsequent flash flooding. An exemplary case is the heavy precipitation episode that occurred in the regions of València, Murcia, and Almería (eastern Spain) on 12 and 13 September 2019. Observed rainfall amounts were close to 500 mm in 48 h, causing seven fatalities and estimated economical losses above 425 million EUR. This case exemplifies the challenging aspects of convective-scale forecasting in the Mediterranean region, with kilometer-resolution meteorological fields required over long forecast spans. Understanding the key mesoscale factors acting on the triggering, location, and intensity of the convective systems responsible for extreme accumulations is essential to gain insight into these episodes and contribute towards their accurate hydrometeorological forecasting. Mesoscale diagnosis suggests that local and distant orography, together with air-sea fluxes, were instrumental in developing convection and intensifying precipitation rate. Sensitivity experiments confirm the role of orography in organizing the cyclonic flow over the southeast part of the western Mediterranean, and also acting as a convection triggering mechanism. Furthermore, results highlight the role of latent heat flux from the Mediterranean Sea in enhancing convective instability at lower levels and moistening the environment. These moist feeding flows substantially contribute to increasing precipitation rates. Such high sensitivity to environmental moisture distribution naturally propagates to the sea surface temperature which, by means of sensible and latent heat flux exchanges, dominated the evolution of convective activity for the 12-13 September 2019 episode.

Computing LPO for Geodynamic Models in ASPECT

2020 ◽  
Author(s):  
Magali Billen ◽  
Menno Fraters
Keyword(s):  
Water Content ◽  
Flow Pattern ◽  
Subduction Zones ◽  
Seismic Anisotropy ◽  
Flow Patterns ◽  
Mantle Flow ◽  
Lattice Preferred Orientation ◽  
Axis Alignment ◽  
Geodynamic Models ◽  
Initial Results

<p>When modeling subduction processes, the results are usually constrained by looking at the geological surface expressions, geochemistry and geophysical observations such as tomography and seismic anisotropy. Of these observations, seismic anisotropy is the only type of observation that can potentially be directly linked to the spatial flow pattern in the mantle. Seismic anisotropy in the mantle is due to lattice-preferred orientation (LPO) of olivine minerals. In subduction environments, which can have complex and changing flow patterns, it is not expected that the LPO necessarily aligns with the flow pattern. This is partly due to the fact that it takes time to realign the LPO and partly because the olivine fast axis alignment depends on the water content and the magnitude of stress. To overcome this problem, the LPO must be computed for realistic and end member subduction zones in order to be able to relate seismic anisotropy to mantle flow and thereby slab dynamics.</p><p>There are many ways to compute LPO. For this study we have used DREX (Kaminski et al., 2004), because the underlying method is accurate and fast enough for use in geodynamic models. To achieve a good and native integration with ASPECT (Kronbichler et al., 2012; Heister et al., 2017; Bangerth et al,. 2019), we have rewritten DREX in CPP as a plugin for ASPECT. In this presentation we will show how it was implemented and what the limitations and possibilities are. Furthermore, we will show initial results from 3D subduction models to study the link between seismic anisotropy and mantle flow.</p>

Sign in / Sign up

Export Citation Format

Share Document