Kinematic reconstructions of the Western Mediterranean area since Triassic time: possible scenarios and their implications for the Apennines

2020 ◽  
Author(s):  
Eline Le Breton
Keyword(s):  
Tectonic Evolution ◽  
Driving Forces ◽  
Tectonic Setting ◽  
Mediterranean Area ◽  
Magnetic Anomalies ◽  
Western Mediterranean ◽  
Plate Boundaries ◽  
The Past ◽  
The North ◽  
Kinematic Evolution

<p>The Western Mediterranean-Alpine belt is remarkable for its tectonic complexity, i.e. strong arcuation of plate boundaries, fast trench retreat, upper-plate extension and switch of subduction/collision polarity around the Adriatic plate (Adria). The kinematic evolution of the Western Mediterranean area is enigmatic due to the intermittently motion of small continental plates (Adria, Iberia and Sardinia-Corsica) that are caught between two major plates (Africa and Europe), converging since Cretaceous time. Reconstructing the past motion of these micro-plates is challenging due to the strong deformation of their boundaries but is key to understand the geodynamic evolution of the whole area.</p><p>The Neogene tectonic evolution is well constrained using magnetic anomalies and transform zones in the Atlantic Ocean for the motion of Europe, Iberia and Africa, and by reconstructing the amount of convergence along fold-and-thrust belts (Apennines, Alps, Dinarides, Provence) and coeval divergence along extensional basins (Liguro-Provencal and Tyrrhenian basins, Sicily Channel Rift Zone) for the motion of Adria and Sardinia-Corsica. Those reconstructions show that Adria had a slight independent motion from Africa and rotated counter-clockwise of about 5º relative to Europe since 20 Ma. However, uncertainties increase and debates arise as one goes back in time. The main debates concern the past motion of Iberia and where its motion relative to Europe is being accommodated in Mesozoic time. Different kinematic scenarios have been proposed depending on the interpretation of paleomagnetic dataset of Iberia, magnetic anomalies in the North Atlantic, and geological-geophysical record of deformation in the Pyrenees and between Iberia and Sardinia-Corsica. Those scenarios have different implications for the tectonic evolution of the Apennines, especially for the Permian-Triassic paleo-tectonic setting of Sardinia, Calabria and Adria, and for the extent and timing of closure of the Liguro-Piemont Ocean. It is important to discuss those implications to better understand subduction processes in the Apennines and their driving forces.</p>

Indicators of Possible Driving Forces for the Spread of Quechua and Aymara Reflected in the Archaeology of Cuzco

2012 ◽  
Author(s):  
GORDON F. McEWAN
Keyword(s):  
Cultural History ◽  
Driving Force ◽  
Driving Forces ◽  
Alternative Possibilities ◽  
The Past ◽  
The North ◽  
The Andes ◽  
Inca Empire ◽  
Culture History ◽  
History Of

Linguistic studies have shown that the traditional idea that the expansion of the Inca Empire was the driving force behind the spread of all Quechua cannot be correct. Across much of its distribution, Quechua has far greater time-depth than can be accounted for by the short-lived Inca Empire. Linguistics likewise suggests that Aymara spread not from the south into Cuzco in the late Pre-Inca period, but also from an origin to the north. Alternative explanations must be sought for the expansion of these language families in the culture history of the Andes. Archaeological studies over the past two decades now provide a broad, generally agreed-upon outline of the cultural history of the Cuzco region. This chapter applies those findings to examine alternative possibilities for the driving forces that spread Quechua and Aymara, offering a clearer cross-disciplinary view of Andean prehistory.

Reduction to the pole of the North American magnetic anomalies

Geophysics ◽  
1990 ◽  
Vol 55 (2) ◽  
pp. 218-225 ◽  
Author(s):  
J. Arkani‐Hamed ◽  
W. E. S. Urquhart
Keyword(s):  
North America ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Gravity Gradient ◽  
Plate Boundaries ◽  
Gravity Gradients ◽  
The North ◽  
Vertical Gravity Gradient ◽  
Regional Tectonic ◽  
Vertical Gravity

Magnetic anomalies of North America are reduced to the pole using a generalized technique which takes into account the variations in the directions of the core field and the magnetization of the crust over North America. The reduced‐to‐the‐pole magnetic anomalies show good correlations with a number of regional tectonic features, such as the Mid‐Continental rift and the collision zones along plate boundaries, which are also apparent in the vertical gravity gradient map of North America. The magnetic anomalies do not, however, show consistent correlation with the vertical gravity gradients, suggesting that magnetic and gravity anomalies do not necessarily arise from common sources.

SIMILARITIES IN THE SURNAMES OF ISLAND AND CONTINENTAL POPULATIONS OF THE NORTH-WESTERN MEDITERRANEAN AREA

2008 ◽  
Vol 40 (3) ◽  
pp. 359-377 ◽  
Author(s):  
E. LUCCHETTI ◽  
M. TASSO ◽  
P. PIZZETTI ◽  
S. DE IASIO ◽  
G. U. CARAVELLO
Keyword(s):  
Genetic Analysis ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Recent History ◽  
Local Populations ◽  
The North ◽  
The Matrix ◽  
Mediterranean Regions ◽  
Geographical Position ◽  
North Western

SummaryThis paper compares the structures of the surnames of 75 municipal populations living in six north-western Mediterranean regions. Its purpose is to unravel the relations between the local populations in Corsica and Sardinia and the links between these populations and those living in the Italian and French continental territory. On the basis of the matrix of similarity of surnames, some topological representations have been drafted showing the above-mentioned relations between populations under the light of their geographical position, their recent history and studies of genetic analysis. Corsica has an eterogeneous surname structure and evident similarity of the north with Tuscany and some centres of continental France. When only the populations of Sardinia were taken into consideration, it emerged that they differ among each other in relation to their geographical position and their history; when, instead, they were considered in relation to other populations outside the island, it was possible to observe that they form a highly different cluster. This study also identified many differences in the analysed geographical areas of Sardinia. In the minor islands – Elba, Giglio, Capraia – the structure of the surnames has a Tuscan origin as well as some similarity with other geographically distant areas, as in the case of the island of Giglio, if compared with some communities of Liguria.

scholarly journals Past African dust inputs in the western Mediterranean area controlled by the complex interaction between the Intertropical Convergence Zone, the North Atlantic Oscillation, and total solar irradiance

2020 ◽  
Vol 16 (1) ◽  
pp. 283-298 ◽  
Author(s):  
Pierre Sabatier ◽  
Marie Nicolle ◽  
Christine Piot ◽  
Christophe Colin ◽  
Maxime Debret ◽  
...  
Keyword(s):  
Mediterranean Area ◽  
Total Solar Irradiance ◽  
Western Mediterranean ◽  
Saharan Dust ◽  
Climatic Forcing ◽  
African Dust ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Wavelet Analyses

Abstract. North Africa is the largest source of mineral dust on Earth, which has multiple impacts on the climate system; however, our understanding of decadal to centennial changes in African dust emissions over the last few millenniums is limited. Here, we present a high-resolution multiproxy analysis of sediment core from high-elevation Lake Bastani, on the island of Corsica, to reconstruct past African dust inputs to the western Mediterranean area over the last 3150 cal BP. Clay mineralogy with palygorskite and a clay ratio associated with geochemical data allow us to determine that terrigenous fluxes are almost exclusively related to atmospheric dust deposition from the western Sahara and Sahel areas over this period. High-resolution geochemical contents provide a reliable proxy for Saharan dust inputs with long-term (millennial) to short-term (centennial) variations. Millennial variations have been correlated with the long-term southward migration of the Intertropical Convergence Zone (ITCZ), with an increase in dust input since 1070 cal BP. This correlation suggests a strong link with the ITCZ and could reflect the increased availability of dust sources to be mobilized with an increase in wind and a decrease in precipitation over western and North Africa. For centennial to decadal variations, wavelet analyses show that since 1070 cal BP, the North Atlantic Oscillation (NAO) has been the main climatic forcing, with an increase in Saharan dust input during the positive phase, as suggested by previous studies over the last decades. However, when the ITCZ is in a northern position, before 1070 cal BP, wavelet analyses indicate that total solar irradiance (TSI) is the main forcing factor, with an increase in African dust input during low TSI. With climate reanalysis over the instrumental era, during low TSI we observe a significant negative anomaly in pressure over Africa, which is known to increase the dust transport. These two climatic forcing factors (NAO, TSI) modulate Saharan dust inputs to the Mediterranean area at a centennial timescale through changes in wind and transport pathways.

Subsidence discrepancy in the Valencia Trough revealed from reflection seismic observations and backstripping results

2020 ◽  
Author(s):  
Penggao Fang ◽  
Geoffroy Mohn ◽  
Julie Tugend ◽  
Nick Kusznir
Keyword(s):  
Tectonic Setting ◽  
Temporal Distribution ◽  
Drill Hole ◽  
Western Mediterranean ◽  
Normal Faults ◽  
Seismic Profiles ◽  
Gulf Of Lions ◽  
North West ◽  
The North ◽  
Valencia Trough

<p>    The Valencia Trough is commonly included as part of the set of western Mediterranean Cenozoic extensional basins that formed in relation with the Tethyan oceanic slab rollback during the latest Oligocene to early Miocene. It lies in a complex tectonic setting between the Gulf of Lions to the North-West, the Catalan Coastal Range and the Iberian chain to the West, the Balearic promontory to the East and the Betic orogenic system to the South. This rifting period is coeval with or directly followed by the development of the external Betics fold and thrust belts at the southern tip of the Valencia Trough. Recent investigations suggest that the Valencia Trough is segmented into two main domains exhibiting different geological and geophysical characteristics between its northeastern and southwestern parts. The presence of numerous Cenozoic normal faults and the well-studied subsidence pattern evolution of the NE part of the Valencia Trough suggest that it mainly formed coevally with the rifting of Gulf of Lion. However, if a significant post-Oligocene subsidence is also evidenced in its SW part; fewer Cenozoic rift structures are observed suggesting that the subsidence pattern likely results from the interference of different processes.</p><p>    In this presentation, we quantify the post-Oligocene subsidence history of the SW part of the Valencia Trough with the aim of evaluating the potential mechanisms explaining this apparent subsidence discrepancy. We analyzed the spatial and temporal distribution of the post-Oligocene subsidence using the interpretation of a dense grid of high-quality multi-channel seismic profiles, also integrating drill-hole results and velocity information from expanding spread profiles (ESP). We used the mapping of the main unconformities, especially the so-called Oligocene unconformity, to perform a 3D flexural backstripping, which permits the prediction of the post-Oligocene water-loaded subsidence. Our results confirm that the post-Oligocene subsidence of the SW part of the Valencia Trough cannot be explained by the rifting of the Gulf of Lions. Previous works already showed that the extreme crustal thinning observed to the SW is related to a previous Mesozoic rift event. Here, we further highlight that if few Cenozoic extensional structures are observed, they can be interpreted as gravitational features rooting at the regionally identified Upper Triassic evaporite level. Backstripping results combined with the mapping of the first sediments deposited on top of the Oligocene unconformity show that they are largely controlled by the shape of Betic front with a possible additional effect of preserved Mesozoic structures. At larger scale, we compare the mechanisms accounting for the origin and subsidence at the SW part of the Valencia Trough with those responsible for the subsidence of its NE part and the Gulf of Lions.</p>

Coastal climatology of the North-Western Mediterranean area for long-term and short-term risk assessment.

2020 ◽  
Author(s):  
Carlo Brandini ◽  
Stefano Taddei ◽  
Valentina Vannucchi ◽  
Michele Bendoni ◽  
Bartolomeo Doronzo ◽  
...  
Keyword(s):  
Risk Assessment ◽  
High Resolution ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Climate Trends ◽  
Short Term ◽  
The North ◽  
The Mediterranean ◽  
North Western

<p>In this work we present the results obtained through a dynamic downscaling of the ERA5 reanalysis dataset (hindcast) of ECMWF, using high-resolution meteorological and wave models defined on unstructured computation grids along the Mediterranean coasts, with a particular focus on the North-Western Mediterranean area. Downscaling of the ERA5 meteorological data is obtained through the BOLAM and MOLOCH models (up to a resolution of 2.5 km) which force an unstructured WW3 model with a resolution of up to 500 m along the coast. Models were validated through available meteorological stations, wave buoy data and X-band wave radars, the latter for the purposes of wave spectra validation.</p><p>On the one hand, this allowed, by extracting the time series of some attack parameters of the waves along the coast, and according to the type of coast (rocky coasts, sandy coasts, coastal structures etc.), to compute the return periods and to characterize the impact of any individual storm. On the other hand, it is possible to highlight some trends observed in the last 30 years, during which recent research is showing an increasing evidence  of some changes in global circulation at regional to local scales. These changes also include effects of wind rotation, wave regimes, storm surges, wave-induced coastal currents and coastal morphodynamics. For example, in the North-Western Mediterranean extreme events belonging to cyclonic weather-types circulation with stronger S-SE components (like the storm of October 28-30th 2018 and many others), rather than events associated with perturbations of Atlantic origin and zonal circulation, are becoming more frequent. These long-term wind/wave climate trends can have consequences not only in the assessment of long-term risk due to main morphodynamic variations (ie. coastal erosion), but also in the short-term risk assessment.</p><p>This work was funded by the EU MAREGOT project (2017-2020) and ECMWF Special Project spitbran  “Evaluation of coastal climate trends in the Mediterranean area by means of high-resolution and multi-model downscaling of ERA5 reanalysis” (2018-2020).</p>

Enhanced aridity and atmospheric high-pressure stability over the western Mediterranean during the North Atlantic cold events of the past 50 k.y.

Geology ◽  
2002 ◽  
Vol 30 (10) ◽  
pp. 863 ◽  
Author(s):  
N. Combourieu Nebout ◽  
J.L. Turon ◽  
R. Zahn ◽  
L. Capotondi ◽  
L. Londeix ◽  
...  
Keyword(s):  
High Pressure ◽  
North Atlantic ◽  
Western Mediterranean ◽  
The Past ◽  
The North ◽  
Cold Events ◽  
The North Atlantic ◽  
Pressure Stability

scholarly journals Assimilation of wind data from airborne Doppler cloud-profiling radar in a kilometre-scale NWP system

2018 ◽  
Author(s):  
Mary Borderies ◽  
Olivier Caumont ◽  
Julien Delanoë ◽  
Véronique Ducrocq ◽  
Nadia Fourrié
Keyword(s):  
Positive Impact ◽  
Heavy Precipitation ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Wind Data ◽  
Heavy Rainfall Event ◽  
Rain Gauges ◽  
The North ◽  
W Band ◽  
The Impact

Abstract. The article reports on the impact of the assimilation of wind vertical profile data in a kilometre-scale NWP system on predicting heavy precipitation events in the north-western Mediterranean area. The data collected in diverse conditions by the airborne W-band radar RASTA (Radar Airborne System Tool for Atmosphere) during a 45-day period are assimilated in the 3-h 3DVar assimilation system of AROME. The impact of the length of the assimilation window is investigated. The data assimilation experiments are performed for a heavy rainfall event, which occurred over south-eastern France on 26 September 2012 (IOP7a), and over a 45-day cycled period. During IOP7a, results indicate that the quality of the rainfall accumulation forecasts increases with the length of the assimilation window. By contrast, on the 45-day period, the best scores against rain gauges measurements are reached with a 1 hour assimilation window, which recommends to use observations with a small period centred on the assimilation time. The positive impact of the assimilation of RASTA wind data is particularly evidenced for the IOP7a case since results indicate an improvement in the predicted wind at short term ranges (2 hours and 3 hours) and in the 12-hour precipitation forecasts. However, on the 45-day cycled period, the comparison against other assimilated observations shows an overall neutral impact. Results are still encouraging since a slight positive improvement in the 6-, 9- and 12-hour precipitation forecasts of heavier rainfall was demonstrated.

Oligocene-Miocene tectonics of the SW Alps and western Apennines coupled orogenic belts, as recorded by their internal and external syn-orogenic basins

2020 ◽  
Author(s):  
Luca Barale ◽  
Piana Fabrizio ◽  
Bertok Carlo ◽  
d'Atri Anna ◽  
Irace Andrea ◽  
...  
Keyword(s):  
Regional Scale ◽  
Foreland Basin ◽  
Mediterranean Area ◽  
Western Alps ◽  
Western Mediterranean ◽  
Northern Apennines ◽  
Kinematic Evolution ◽  
Ligurian Alps ◽  
Internal Side ◽  
Miocene Tectonics

<p>The Oligocene-Miocene evolution of the westernmost part of the Northern Apennines was constrained firstly by Oligocene E-W regional sinistral shearing and then by Early Miocene shortening and Middle to Late Miocene NW-SE dextral transpression affecting the southern termination of the Western Alps arc (Maritime and Ligurian Alps) and the substrate of the Tertiary Piemonte Basin (TPB), which started to be incorporated, in the same time span, in the Northern Apennines belt</p><p>In other words, the dynamics accommodating the different motion of the WNW-directed Adria and SW Alps with respect to the ENE-directed Ligurian-Corso-Sardinian block also controlled the evolution of TPB and its Ligurian substrate since at least the Aquitanian, when a regional conterclockwise rotation began and a deep reshaping of the basin occurred, due to predominant NE-SW shortening concomitant with the Northern Apennines thrust fronts propagation (Burdigalian). On the other side, the infilling of the SW Alps foreland basin was partially controlled also by the resedimentation of non-metamorphic Cretaceous-Paleocene Ligurian units previously deposited along the Briançonnais-Dauphinois continental margin. The subsequent Late Burdigalian to Serravallian extension in the internal side of the SW Alps allowed the creation of accomodation space and the deposition of relevant thickness of sediments in the TPB, during the coeval progressive uplifting of Alpine crystalline and metamorphic units (e.g. the Argentera Massif and Dora-Maira Unit). This Alpine process constrained the shape and evolution of the TPB syn-orogenic sub-basins and their subsequent tectonic paths within the NW Apennines belt, while it was being built. The steps of this Alps-Apennines evolution have been clearly recorded by a set of regional scale, Oligocene to Pleistocene unconformities that can be continuously traced at surface in the southern part of the Piemonte region and in the subsurface of the western Po plain.</p><p>We thus remark that the evolution of the westernmost part of the Apennines can be studied largely referring to the Alpine geodynamics, since, although the Alps and the Apennines are two distinct geomorphologic and geophysical entities at the scale of the Western Mediterranean area, they share common synorogenic basins and consistent kinematic evolution in their junction zone of NW Italy.</p>

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