Propos sur les geosynclinaux

1961 ◽  
Vol S7-III (7) ◽  
pp. 629-711 ◽  
Author(s):  
Jean Aubouin

Abstract Geosynclinal theory began with the characteristics found in the geosynclinal chains of the Alpine cycle in Europe, then, after much research, was modified to include Prealpine chains, the Hercynian (Variscan), Caledonian, and Precambrian. The fundamental organization is found to be the eugeosynclinal-miogeosynclinal couple. These couples are repeated in two types of symmetry, centrifugal and centripetal, in the manner of centrifugally-symmetrical bicouples. The classic chain's double character, with the median zone either an intermediate massif of the Zwischenberg type, an intermediate trough, or eugeanticlinal and eugeosynclinal folds, influences the orogenic, magmatic and metamorphic gradients toward the exterior. The eugeosynclinal-miogeosynclinal couple itself is defined by the paleogeography, the polarity, and the tectonic structures. Geosynclinal, tardigeosynclinal, and postgeosynclinal periods are recognized, but seem to be of lesser importance with greater age of the geosynclinal development.

2013 ◽  
pp. 160-166
Author(s):  
Izabela Front

The present article seeks to analyze the way in which the blasphemous figure of God in Dolce agonia by Nancy Huston allows the author to describe the sacred element in human life, seen as deprived of transcendental character. This is possible thanks to the three aspects of the text dependent on the type of God’s figure, which are: the contrast between passages marked by the cynical God’s voice and passages focused on man’s life filled with suffering; the tone and the appropriation of time var-iations and, finally, the double character of God who, at the same time, is indifferent to man’s lot while touched by his capacity of love.


Author(s):  
Andrei V. Prokopiev ◽  
Felix F. Tretyakov ◽  
Dmitry A. Vasiliev
Keyword(s):  

2021 ◽  
Author(s):  
Francesca D’Ajello Caracciolo ◽  
Rodolfo Console

AbstractA set of four magnitude Ml ≥ 3.0 earthquakes including the magnitude Ml = 3.7 mainshock of the seismic sequence hitting the Lake Constance, Southern Germany, area in July–August 2019 was studied by means of bulletin and waveform data collected from 86 seismic stations of the Central Europe-Alpine region. The first single-event locations obtained using a uniform 1-D velocity model, and both fixed and free depths, showed residuals of the order of up ± 2.0 s, systematically affecting stations located in different areas of the study region. Namely, German stations to the northeast of the epicenters and French stations to the west exhibit negative residuals, while Italian stations located to the southeast are characterized by similarly large positive residuals. As a consequence, the epicentral coordinates were affected by a significant bias of the order of 4–5 km to the NNE. The locations were repeated applying a method that uses different velocity models for three groups of stations situated in different geological environments, obtaining more accurate locations. Moreover, the application of two methods of relative locations and joint hypocentral determination, without improving the absolute location of the master event, has shown that the sources of the four considered events are separated by distances of the order of one km both in horizontal coordinates and in depths. A particular attention has been paid to the geographical positions of the seismic stations used in the locations and their relationship with the known crustal features, such as the Moho depth and velocity anomalies in the studied region. Significant correlations between the observed travel time residuals and the crustal structure were obtained.


Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 125
Author(s):  
Giacomo Prosser ◽  
Giuseppe Palladino ◽  
Dario Avagliano ◽  
Francesco Coraggio ◽  
Eleonora Maria Bolla ◽  
...  

This paper shows the main results of a multidisciplinary study performed along the southeastern sector of the Agri Valley in Basilicata (Southern Italy), where Cenozoic units, crucial for constraining the progressive evolution of the Southern Apennine thrust and fold belt and, more in general, the geodynamic evolution of the Mediterranean area are widely exposed. In particular, we aimed at understanding the stratigraphic and tectonic setting of deep-sea, thrust-top Cenozoic units exposed immediately to north of Montemurro, between Costa Molina and Monte dell’Agresto. In the previous works different units, showing similar sedimentological characteristics but uncertain age attribution, have been reported in the study area. In our study, we focussed on the Albidona Formation, pertaining to the Liguride realm, which shows most significant uncertainties regarding the age and the stratigraphic setting. The study was based on a detailed field survey which led to a new geological map of the area. This was supported by new stratigraphic, biostratigraphic and structural analyses. Biostratigraphic analysis provided an age not older than the upper Ypresian and not younger than the early Priabonian. Recognition of marker stratigraphic horizons strongly helped in the understanding of the stratigraphy of the area. The study allowed a complete revision of the stratigraphy of the outcropping Cenozoic units, the recognition of until now unknown tectonic structures and the correlation between surface and subsurface geology.


2020 ◽  
Vol 12 (1) ◽  
pp. 1185-1199
Author(s):  
Mirosław Kamiński

AbstractThe research area is located on the boundary between two Paleozoic structural units: the Radom–Kraśnik Block and the Mazovian–Lublin Basin in the southeastern Poland. The tectonic structures are separated by the Ursynów–Kazimierz Dolny fault zone. The digital terrain model obtained by the ALS (Airborne Laser Scanning) method was used. Classification and filtration of an elevation point cloud were performed. Then, from the elevation points representing only surfaces, a digital terrain model was generated. The model was used to visually interpret the course of topolineaments and their automatic extraction from DTM. Two topolineament systems, trending NE–SW and NW–SE, were interpreted. Using the kernel density algorithm, topolineament density models were generated. Using the Empirical Bayesian Kriging, a thickness model of quaternary deposits was generated. A relationship was observed between the course of topolineaments and the distribution and thickness of Quaternary formations. The topolineaments were compared with fault directions marked on tectonic maps of the Paleozoic and Mesozoic. Data validation showed consistency between topolineaments and tectonic faults. The obtained results are encouraging for further research.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1499
Author(s):  
Davide Fronzi ◽  
Francesco Mirabella ◽  
Carlo Cardellini ◽  
Stefano Caliro ◽  
Stefano Palpacelli ◽  
...  

The interaction between fluids and tectonic structures such as fault systems is a much-discussed issue. Many scientific works are aimed at understanding what the role of fault systems in the displacement of deep fluids is, by investigating the interaction between the upper mantle, the lower crustal portion and the upraising of gasses carried by liquids. Many other scientific works try to explore the interaction between the recharge processes, i.e., precipitation, and the fault zones, aiming to recognize the function of the abovementioned structures and their capability to direct groundwater flow towards preferential drainage areas. Understanding the role of faults in the recharge processes of punctual and linear springs, meant as gaining streams, is a key point in hydrogeology, as it is known that faults can act either as flow barriers or as preferential flow paths. In this work an investigation of a fault system located in the Nera River catchment (Italy), based on geo-structural investigations, tracer tests, geochemical and isotopic recharge modelling, allows to identify the role of the normal fault system before and after the 2016–2017 central Italy seismic sequence (Mmax = 6.5). The outcome was achieved by an integrated approach consisting of a structural geology field work, combined with GIS-based analysis, and of a hydrogeological investigation based on artificial tracer tests and geochemical and isotopic analyses.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiziana Sgroi ◽  
Alina Polonia ◽  
Graziella Barberi ◽  
Andrea Billi ◽  
Luca Gasperini

AbstractThe Calabrian Arc subduction-rollback system along the convergent Africa/Eurasia plate boundary is among the most active geological structures in the Mediterranean Sea. However, its seismogenic behaviour is largely unknown, mostly due to the lack of seismological observations. We studied low-to-moderate magnitude earthquakes recorded by the seismic network onshore, integrated by data from a seafloor observatory (NEMO-SN1), to compute a lithospheric velocity model for the western Ionian Sea, and relocate seismic events along major tectonic structures. Spatial changes in the depth distribution of earthquakes highlight a major lithospheric boundary constituted by the Ionian Fault, which separates two sectors where thickness of the seismogenic layer varies over 40 km. This regional tectonic boundary represents the eastern limit of a domain characterized by thinner lithosphere, arc-orthogonal extension, and transtensional tectonic deformation. Occurrence of a few thrust-type earthquakes in the accretionary wedge may suggest a locked subduction interface in a complex tectonic setting, which involves the interplay between arc-orthogonal extension and plate convergence. We finally note that distribution of earthquakes and associated extensional deformation in the Messina Straits region could be explained by right-lateral displacement along the Ionian Fault. This observation could shed new light on proposed mechanisms for the 1908 Messina earthquake.


1969 ◽  
Vol 14 (4) ◽  
pp. 127-130
Author(s):  
M. M. CHARYGIN ◽  
Yu. G. BOGOMOLOV

Author(s):  
Thierry Abou’ou Ango ◽  
Bernard Njom ◽  
Armel Zacharie Ekoa Bessa ◽  
Jacques Bertrand Onana ◽  
Tasin Bafon Godlove ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document