scholarly journals Recent deeper geophysical results better account for the tectonics in the Italian area

1997 ◽  
Vol 40 (5) ◽  
Author(s):  
C. Morelli
Keyword(s):  
Oceanic Crust ◽  
Sedimentary Basins ◽  
Tyrrhenian Sea ◽  
Geological Data ◽  
Ligurian Sea ◽  
Po Plain ◽  
Adriatic Plate ◽  
The Alps ◽  
Tectonic Features ◽  
European Plate

Results from extended DSS profiles (1956-1986) in Italy and surrounding land and sea areas offer good constraints for other geophysical and geological data. Integrated interpretations outline the main tectonic features. Collisional tectonics is predominant in the Alps, for which the Adriatic plate acted as hinterland against the European plate foreland. Main results: W-wards, NW- and N-wards oriented overthrusting on the European crust, bending of the lower European crust, European Moho to 70 km depth with the Adriatic mantle indented above, crustal doubling (Adriatic over the European one). In the Apennines, on the contrary, the Adriatic plate acted as a foreland, against the overthrusts generated by the Tuscanian and Tyrrhenian mantellic bodies, heated, elevated and migrated NE-wards and SE-wards, respectively. Also the Adriatic plate bends under this load-centripetally towards the Tyrrhenian sea, so that the Adriatic Moho from 35 km depth is presumed to descend through a flexure till 40-50 km below the Tuscanian and Tyrrhenian land areas. The external peri-Apenninic area is still in compression and includes thick sedimentary basins, from the Po-plain to Sicily. The internal area is in extension, overlapped by thin, stretched crusts of Ligurian and Tyrrhenian origin, whose remnants occupy most of both seas areas, with two areas of oceanic crust in the SE-Tyrrhenian. Rifting and opening is in action also in the Ligurian Sea and Sicily Strait.

scholarly journals Current knowledge on the crustal properties of Italy

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
C. Morelli
Keyword(s):  
Adriatic Sea ◽  
Current Knowledge ◽  
Gravity Data ◽  
Maximum Depth ◽  
Gravity Models ◽  
Tyrrhenian Sea ◽  
Po Plain ◽  
Reflection Seismic ◽  
Adriatic Plate ◽  
The North

The recent advances in experimental petrography together with the information derived from the super-deep drilling projects have provided additional constraints for the interpretation of refraction and reflection seismic data. These constraints can also be used in the interpretation of magnetic and gravity data to resolve nonuniqueness. In this study, we re-interpret the magnetic and gravity data of the Italian peninsula and neighbouring areas. In view of the constraints mentioned above, it is now possible to find an agreement between the seismic and gravity models of the Central Alps. By taking into account the overall crustal thickness, we have recognized the existence of three types of Moho: 1) European which extends to the north and west of the peninsula and in the Corsican-Sardinian block. Its margin was the foreland in the Alpine Orogeny and it was the ramp on which European and Adriatic mantle and crustal slices were overthrusted. This additional load caused bending and deepening and the Moho which now lies beneath the Adriatic plate reaching a maximum depth of approximately 75 km. 2) Adriatic (or African) which lies beneath the Po plain, the Apennines and the Adriatic Sea. The average depth of the Moho is about 30-35 km below the Po plain and the Adriatic Sea and it increases toward the Alps and the Tyrrhenian Sea (acting as foreland along this margin). The maximum depth (50 km) is reached in Calabria. 3) Pery-Tyrrhenian. This is an oceanic or thinned continental crust type of Moho. It borders the oceanic Moho of the Tyrrhenian Sea and it acquires a transitional character in the Ligurian and Provençal basins (<15 km thickness) while further thickening occurs toward the East where the Adriatic plate is overthrusted. In addition, the interpretation of the heat flow data appears to confirm the origin of this Moho and its geodynamic allocation.

scholarly journals Comparison between XBT data and TOPEX/Poseidon satellite altimetry in the Ligurian-Tyrrhenian area

2003 ◽  
Vol 21 (1) ◽  
pp. 123-135 ◽  
Author(s):  
S. Vignudelli ◽  
P. Cipollini ◽  
F. Reseghetti ◽  
G. Fusco ◽  
G. P. Gasparini ◽  
...  
Keyword(s):  
Pilot Project ◽  
Atlantic Water ◽  
Data Sets ◽  
Tyrrhenian Sea ◽  
Satellite Altimeter ◽  
Ligurian Sea ◽  
Data Set ◽  
Additional Information ◽  
Forecasting System ◽  
Computational Errors

Abstract. From September 1999 to December 2000, eXpendable Bathy-Thermograph (XBT) profiles were collected along the Genova-Palermo shipping route in the framework of the Mediterranean Forecasting System Pilot Project (MFSPP). The route is virtually coincident with track 0044 of the TOPEX/Poseidon satellite altimeter, crossing the Ligurian and Tyrrhenian basins in an approximate N–S direction. This allows a direct comparison between XBT and altimetry, whose findings are presented in this paper. XBT sections reveal the presence of the major features of the regional circulation, namely the eastern boundary of the Ligurian gyre, the Bonifacio gyre and the Modified Atlantic Water inflow along the Sicily coast. Twenty-two comparisons of steric heights derived from the XBT data set with concurrent realizations of single-pass altimetric heights are made. The overall correlation is around 0.55 with an RMS difference of less than 3 cm. In the Tyrrhenian Sea the spectra are remarkably similar in shape, but in general the altimetric heights contain more energy. This difference is explained in terms of oceanographic signals, which are captured with a different intensity by the satellite altimeter and XBTs, as well as computational errors. On scales larger than 100 km, the data sets are also significantly coherent, with increasing coherence values at longer wavelengths. The XBTs were dropped every 18–20 km along the track: as a consequence, the spacing scale was unable to resolve adequately the internal radius of deformation (< 20 km). Furthermore, few XBT drops were carried out in the Ligurian Sea, due to the limited north-south extent of this basin, so the comparison is problematic there. On the contrary, the major features observed in the XBT data in the Tyrrhenian Sea are also detected by TOPEX/Poseidon. The manuscript is completed by a discussion on how to integrate the two data sets, in order to extract additional information. In particular, the results emphasize their complementariety in providing a dynamically complete description of the observed structures. Key words. Oceanography: general (descriptive and regional oceanography) Oceanography: physical (sea level variations; instruments and techniques)

The arc of the Western Alps : understanding its kinematics and formation mechanisms based on new structural and paleomagnetic datas, and thermo-mechanical modelling.

2021 ◽  
Author(s):  
Quentin Brunsmann ◽  
Claudio Rosenberg ◽  
Nicolas Bellahsen ◽  
Laetitia Le Pourhiet
Keyword(s):  
Western Alps ◽  
Strike Slip ◽  
Rheological Parameters ◽  
The South ◽  
Adriatic Plate ◽  
The North ◽  
Field Evidence ◽  
Internal Zone ◽  
The Alps ◽  
East West

&lt;p&gt;The Alps have an overall East-West orientation, which changes radically in their western termination, where they rotate southward into a N-S strike, and then eastward into an E-W strike, forming the arc of the Western Alps. This arc is commonly inferred to have formed during collision, due to indentation of the Adriatic plate into the European continental margin. Several models attempted to provide a kinematic explanation for the formation of this arched, lateral end of the Alps. Indeed, the radial nature of the transport directions observed along the arc of the Western Alps cannot be explained by a classic convergence model.&lt;br&gt;For more than 50 years the formation of this arc was been associated to westward-directed indentation of Adria, accommodated along East-West oriented strike-slip faults, a sinistral one in the South of the arc and a dextral one in the North. The dextral one correspond to the Insubric Fault. The sinistral strike-slip zone, inferred to be localized along the &amp;#171;Stura corridor&amp;#187; (Piedmont, Italy) would correspond to a displacement of 100 to 150 km according to palaeogeographical, and geometric analyses. However, field evidence is scarce and barely documented in the literature.&lt;br&gt;Vertical axis rotations of the Adriatic indenter also inferred to be syn-collisional could have influenced the acquisition of the morphology of the arc. Paleomagnetic analyses carried out in the Internal Zone and in the Po plain suggest a southward increading amount of counter-clockwise rotation of the Adriatic plate and the Internal Zone, varying from 20&amp;#176;-25&amp;#176; in the North to nearly 120&amp;#176; in the South.&lt;br&gt;Dextral shear zones possibly accommodating this rotation in some conceptual models is observed in several places below the Penninic Front and affect the Argentera massif to the south. However, the measured displacement quantities do not appear to be equivalent to those induced by such rotations.&lt;br&gt;The present study aims to constrain the kinematic evolution of the arc of the Western Alps through a multidisciplinary approach. The first aspect of this project is the structural analysis of the area (Stura corridor) inferred to accommodate large sinistral displacements allowing for the westward indentation of the Adriatic indenter. We discuss the general lack of field evidence supporting sinistral strike-slip movements, in contrast to large-scale compilation of structures suggesting the possible occurrence of such displacement. The second part consists of a palaeomagnetic study, in which new data are integred with a compilation of already existing data. This compilation shows that several parts of the arc in the External Zone did not suffer any Cenozoic rotations, hence suggesting that a proto-arc already axisted at the onset collision, as suggested by independent evidence of some paleogeographic reconstruction. Finally, 2D and 3D thermo-mechanical modeling in using the pTatin3D code is used to test which structural (geometrical), and rheological parameters affected the first-order morphology of the Western Alpin arc and its kinematics. The synthesis of these different approaches allows us to propose a new model explaining the kinematics and the mechanisms of formation of the Western Alps arc.&lt;/p&gt;

Historical Land Uses and Their Changes in the European Alps

2019 ◽  
Author(s):  
Ulrike Tappeiner ◽  
Erich Tasser
Keyword(s):  
Land Use ◽  
20Th Century ◽  
Land Reclamation ◽  
Alpine Region ◽  
Ecosystem Functions ◽  
Mountain Range ◽  
European Alps ◽  
Ligurian Sea ◽  
Arable Farming ◽  
The Alps

The Alps are the highest and largest mountain range in Europe. They extend from the Ligurian Sea to the Pannonian Basin in an arc 744 miles (1,200 km) long and between 93 and 155 miles (150–250 km) wide. The settlement history of this large European landscape is closely linked to the settlement of Europe as a whole, whereby the inner Alpine region was not permanently settled until around 4500 bce because of topographical and climatic disadvantages. Dense forest cover initially made it difficult to use large grazing areas, but transhumance gradually developed in the Alpine region when the animals spent their summers high up in the mountains and their winters in the valleys. At about the same time, the Alpine self-sufficiency economy of arable farming and livestock breeding was added, which made permanent settlement possible. However, the most intensive settlement and land reclamation advance took place in the Middle Ages. In the 19th century, industrialization reached the Alpine region a little delayed, and globalization in the middle of the 20th century. This also led to a fundamental change in society. The previous agricultural society was replaced by the service society of the 20th century. Developments since the late 1950s have taken place against the background of developments in the European Union (EU) as a whole, above all the Common Agricultural Policy and the European Spatial Development Perspective (ESDP), but these developments were and still are influenced by additional agreements specific to the Alps, such as the Alpine Convention, the Alpine Protection Commission (CIPRA), and the Alpine Working Community (Arge Alp). All these factors mean that historical and current development of land use in the Alpine region has been and is always linked to developments in Europe. Many studies on land use in the Alpine region should therefore be seen in this context. Moreover, past land use often has long-lasting legacy effects on ecosystems and their development. Therefore, in this article we deal not only with historical land use but also with current and future developments and their impacts on ecosystem functions and services.

Evolution of Antarctic prospective sedimentary basins

1989 ◽  
Vol 1 (1) ◽  
pp. 51-56 ◽  
Author(s):  
V.L. Ivanov
Keyword(s):  
Sedimentary Basins ◽  
Passive Margin ◽  
Mobile Belt ◽  
Continental Shelves ◽  
The Pacific ◽  
Different Types ◽  
Tectonic Features ◽  
Stratigraphic Evolution ◽  
Continental Glaciation ◽  
The Antarctic

No less than 15–20 sedimentary basins are now known on the Antarctic continental landmass and surrounding continental shelves. Reconstruction of their tectonic and stratigraphic evolution is a specialized task. Owing to the polar position of the continent, the Pacific and Atlantic global geostructures are closely spaced there and the interplay between them is strong enough to result in hybridization of the characteristic tectonic features of the various basins. The present morphostructure of the southern polar region of the Earth is characterized by a prominent circumpolar zoning. Therefore, the sedimentary basins form a gigantic ring along the continental margin, including both the shelf proper and the edge of the continent. Within the ring, the basins are associated with different types of margins successively replacing each other, from the Mesozoic magmatic are in the Pacific segment to the classic passive margin off East Antarctica. The formation of the sedimentary basins in the Antarctic segment of the Pacific mobile belt was a part of a single process of geosynclinal development, whereas on the craton flank the process was superposed on the continental structures by rifting during Gondwana fragmentation. During post-break-up tectonism, continental glaciation played an important part in the formation of the sedimentary basins.

scholarly journals Bien Dong seafloor spreading and its influence to formation & development of sedimentary basins

2014 ◽  
Vol 17 (3) ◽  
pp. 132-138
Author(s):  
Hung Nguyen Manh ◽  
Tieng Hoang Dinh
Keyword(s):  
Continental Crust ◽  
Oceanic Crust ◽  
Sedimentary Basins ◽  
Seafloor Spreading ◽  
Fault System ◽  
Basalt Magma ◽  
Deep Fault ◽  
Thermal Anomalies ◽  
South West ◽  
Favorable Conditions

The paper presents the characteristics of Bien Dong seafloor spreading which including two parts: The Eastern part is quite large, in which developed by Eastern- Western orientation (spreading on N-S). The Southern- Western part gradually changed its orientation from E-W into East- North and in to South- West at the end (spreading SE- NW). There are two main dynamic resources created the spreading and deformation: The appearance of thermal abnormality by mantle plume occurred 36 M.a. until 14 M.a. The Eastern thermal anomalies continued to develop follow this orientation. In the SW- part the thermal anomalies changed it orientation from E-W into NE- SW 26 M.a and gradually developing toward S-W. Since 14 M.a, both two these trends been stopped, began to cooling and shrinkage. The abnormal existence caused pinchout and rifting the continental crust in Bien Dong Center and generating new oceanic crust as well. The uplift and variation of thermal abnormality (basalt magma) raised up the favorable conditions to forming, developing and varying the axis of Bien Dong spreading seafloor. The all above synthetic activities created favorable conditions for generation and development a series of deep fault systems with E-W direction in Eastern part and NE- SW direction in Southern-Western direction in remain part, and created and evolved the sedimentary basins in margins of Bien Dong with along the main deep fault system.

scholarly journals Slab Break-offs in the Alpine Subduction Zone

2019 ◽  
Author(s):  
Emanuel D. Kästle ◽  
Claudio Rosenberg ◽  
Lapo Boschi ◽  
Nicolas Bellahsen ◽  
Thomas Meier ◽  
...  
Keyword(s):  
Deep Structure ◽  
Body Wave ◽  
Eastern Alps ◽  
Central Alps ◽  
Slab Geometry ◽  
Tomographic Images ◽  
Velocity Anomaly ◽  
The Alps ◽  
Geological Constraints ◽  
European Plate

Abstract. After the onset of plate collision in the Alps, at 32–34 Ma, the deep structure of the orogen is inferred to have changed dramatically: European plate break-offs in various places of the Alpine arc, as well as a possible reversal of subduction polarity in the eastern Alps have been proposed. We review body-wave tomographic studies, compare them to our surface-wave-derived model for the uppermost 200 km, and reinterpret them in terms of slab geometries. We infer that the shallow subducting portion of the European plate is likely detached under both the western and eastern (but not the central) Alps. The Alps-Dinarides transition may be explained by a combination of European and Adriatic subduction. This would imply that the deep, high-velocity anomaly (> 200 km depth) mapped by tomographers under the eastern Alps is a detached segment of the European plate. The shallower fast anomaly (100–200 km depth) can be ascribed to European or Adriatic subduction, or both. These findings are compared to previously proposed models for the eastern Alps in terms of slab geometry, but also integrated in a new, alternative geodynamic scenario that best fits both tomographic images and geological constraints.

Mediterranean fish biodiversity: an updated inventory with focus on the Ligurian and Tyrrhenian seas

Zootaxa ◽  
2012 ◽  
Vol 3263 (1) ◽  
pp. 1 ◽  
Author(s):  
PETER NICK PSOMADAKIS ◽  
STEFANO GIUSTINO ◽  
MARINO VACCHI
Keyword(s):  
Tyrrhenian Sea ◽  
Ligurian Sea ◽  
Mediterranean Areas ◽  
Thermophilic Species ◽  
Atlantic Origin ◽  
Southern Mediterranean ◽  
Southern Tyrrhenian Sea ◽  
Immigrant Species ◽  
The Mediterranean ◽  
Mediterranean Fish

In this paper we update the Mediterranean fish inventory, analyse the biogeographic features of this fauna and provideexhaustive biodiversity data for the Ligurian and Tyrrhenian seas. According to the data available in 2010, the Mediterraneanfish diversity can be summarized as follows: 602 (including sub-species) bony fish species (Osteichthyes), 79 cartilaginous fishspecies (Chondrichthyes) and 3 cyclostomes (Agnatha); making a total of 684 species belonging to 173 families (147Osteichthyes, 24 Chondrichthyes, 2 Agnatha). Most species 403 (58.9%) have an Atlantic origin, 128 (18.7%) species arecosmopolitan, 90 (13.2%) species are Indo-Pacific, and 63 (9.2%) are endemic to the Mediterranean. In the Ligurian Sea,northern Tyrrhenian and southern Tyrrhenian Sea, the richness can be estimated at 454, 426 and 447 species, respectively. Themost speciose families for the Mediterranean as a whole, but also for the three intra-mediterranean areas studied are theGobiidae, Sparidae, Labridae and Blenniidae; whereas Carangidae is a numerically important family mainly at theMediterranean level. The percentage of endemic fishes within the intra-mediterranean areas studied gradually decrease acrosslatitude from the Ligurian Sea (9.4%) to the northern (8.7%) and southern (8.0%) Tyrrhenian Sea. The updated fish inventorycontains 81 Lessepsian and 48 Atlantic immigrant species, which represent 11.8% and 7.0% of the whole Mediterranean fishcommunity, respectively. The Ligurian Sea (3.1%) houses a higher amount of immigrants with respect to the northern (1.6%)and southern (2.7%) Tyrrhenian sectors.Field observations made during this study indicate that both the Ligurian and Tyrrhenian seas are presently subjected toincreasing colonization events by thermophilic species spreading from the southern Mediterranean and to a lesser degree by the arrival of exotic species either of Atlantic or Indo-Pacific origin.

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