A rootless suture and the loss of the roots of a mountain chain: The Variscan belt of NW Iberia     

José R. Martínez Catalán  Ricardo Arenas  Jacobo Abati  Sonia Sánchez Martínez  Florentino Díaz García  Javier Fernández Suárez  Pablo González Cuadra  Pedro Castiñeiras  Juan Gómez Barreiro  Alejandro Díez Montes  Emilio González Clavijo  Francisco J. Rubio Pascual  Pilar Andonaegui  Teresa E. Jeffries  James E. Alcock  Rubén Díez Fernández  Alicia López Carmona 《Comptes Rendus Geoscience》2009,341(2-3):114-126

Ophiolites of different Paleozoic ages occur in North-West (NW) Iberia in a rootless suture representing the remnants of the Rheic Ocean. Associated allochthonous terranes in the hanging- and foot-walls of the suture derive from the former margins, whereas the relative autochthon corresponds to the Paleozoic passive margin of northern Gondwana. The Paleozoic tectonic evolution of this part of the circum-Atlantic region is deduced from the stratigraphical, petrological, structural and metamorphic evolution of the different units and their ages. The tectonic reconstruction covers from Cambro-Ordovician continental rifting and the opening of the Rheic Ocean to its Middle to Upper Devonian closure. Then, the Variscan Laurussia–Gondwana convergence and collision is briefly described, from its onset to the late stages of collapse associated with the demise of the orogenic roots.  相似文献   

Drying and dying of a subducted slab: Coupled Li and B isotope variations in Western Anatolia Cenozoic Volcanism   总被引：1，自引：0，他引：1  

Samuele Agostini  Jeffrey G. Ryan  Sonia Tonarini  Fabrizio Innocenti   《Earth and Planetary Science Letters》2008,272(1-2):139-147

In lavas spanning ~ 10Ma of subduction-related volcanism in Western Anatolia, we observe remarkably similar patterns of δ⁷Li and δ¹¹B variation. In this setting, magmatism records a transition from calc–alkaline to ultrapotassic character, consistent with overall lower mean extents of melting, and a changing mantle source that reflects a fractionating, higher temperature slab input consistent with the gradual cessation of subduction. Subsequent rift-related intraplate magmatism record δ⁷Li signatures within the range observed for MORBs and OIBs, indicating an abrupt transition to a mantle source unmodified by subduction.  相似文献   

Seismic response and energy dissipation of 3D complex steel buildings considering the influence of interior semi-rigid connections: low- medium- and high-rise     

Alfredo Reyes-Salazar  José M. Sauceda-Pimentel  Sonia E. Ruiz  Edén Bojórquez  Juan Bojorquez 《Bulletin of Earthquake Engineering》2018,16(11):5557-5590

A numerical investigation regarding the seismic behavior of complex-3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (GF) is conducted. The interior connections are assumed to be first perfectly pinned (PP) and then semi-rigid (SR); the two model responses are compared. Three steel building models representing low-, medium- and high-rise buildings, and several strong motions are used. The relative stiffness of SR connections is calculated according to the Richard Model and the Beam Line Theory. The Ruaumoko Computer Program is used to perform the required step-by-step nonlinear seismic analysis. Results indicate that interstory shears and interstory displacements at PMRF may be significantly reduced when interior connections are modeled as SR. Average reductions of up to 20, 46 and 11% are observed for interstory shears, for low-, medium-, and high-rise buildings, respectively. The corresponding reductions for interstory displacements are about 14, 44 and 15%. The contribution of GF to the lateral resistance is considerable, which significantly increases when the connections are modeled as SR; relative contributions larger than 80% are observed. The dissipated energy (DE) at PMRF is larger for the buildings with PP than for the buildings with SR connections indicating that damage at PMRF is reduced. Thus, the effect of the stiffness and the DE at interior connections should not be ignored. However, the design of some elements, particularly columns of the GF, has to be revised; these members may not be able to support the loads produced by the neglected lateral contribution if they are not properly designed.  相似文献   

Comparison of numerical hindcasted severe waves with Doppler radar measurements in the North Sea   总被引：1，自引：1，他引：0  

Sonia Ponce de León  João H. Bettencourt  Frederic Dias 《Ocean Dynamics》2017,67(1):103-115

Severe sea states in the North Sea present a challenge to wave forecasting systems and a threat to offshore installations such as oil and gas platforms and offshore wind farms. Here, we study the ability of a third-generation spectral wave model to reproduce winter sea states in the North Sea. Measured and modeled time series of integral wave parameters and directional wave spectra are compared for a 12-day period in the winter of 2013–2014 when successive severe storms moved across the North Atlantic and the North Sea. Records were obtained from a Doppler radar and wave buoys. The hindcast was performed with the WAVEWATCH III model (Tolman 2014) with high spectral resolution both in frequency and direction. A good general agreement was obtained for integrated parameters, but discrepancies were found to occur in spectral shapes.  相似文献   

Transformation of social capital during and after a disaster event: the cases Chañaral and Diego de Almagro,Atacama Region,Chile     

Castro-Correa  Carmen-Paz  Aldunce Ide  Paulina  Wyndham Vásquez  Katherine  Mena Maldonado  Dania  Pérez Tello  Sonia 《Natural Hazards》2020,103(2):2427-2440

Natural Hazards - This article analyzes the impact of socio-natural disasters on social capital at a local level, studying the cases of the communities of Chañaral and Diego de Almagro after...  相似文献   

Temporal study of estrogenic responses of mussel (Mytilus galloprovinciallis) extracts applied to reporter cell lines     

David A  Dagnino S  Pichot Y  Munaron D  Escande A  Casellas C  Fenet H  Gomez E 《Marine environmental research》2008,66(1):105-107

In vitro bioassays would facilitate monitoring of estrogen-like compounds in mussels (Mytilus galloprovincialis) since they tend to accumulate lipophilic compounds in their fat and muscle tissue. However, estradiol (E2) steroid (already identified in mussels) could induce false positive responses. This study focuses on temporal variability in estrogenic responses of mussel extracts and the possible relation of this response with E2 levels. The reproductive cycle and growth were thus monitored for six months in sexed mussels. E2 levels were similar between genders and these levels varied with reproductive stages. human estrogen receptor (hER) activities were similar at all stages except in February. E2 present in male and female extracts accounted for part of the hER activation observed, but no correlation was found between E2 levels and hER activities.  相似文献   

Influence of tropical Pacific SST on seasonal precipitation in Colombia: prediction using El Niño and El Niño Modoki     

Samir Córdoba-Machado  Reiner Palomino-Lemus  Sonia Raquel Gámiz-Fortis  Yolanda Castro-Díez  María Jesús Esteban-Parra 《Climate Dynamics》2015,44(5-6):1293-1310

  相似文献   

The Bazar Ophiolite of NW Iberia: a relic of the Iapetus–Tornquist Ocean in the Variscan suture     

Sonia S. Martínez  Axel Gerdes  Ricardo Arenas  Jacobo Abati 《地学学报》2012,24(4):283-294

  相似文献   

Quasi-periodic fluctuations in the Greenland–Iceland–Norwegian Seas region in a coupled climate model   总被引：1，自引：1，他引：0  

Sonia R. Gamiz-Fortis  Rowan T. Sutton 《Ocean Dynamics》2007,57(6):541-557

We report an analysis of the mechanisms responsible for interannual variability in the Greenland–Iceland–Norwegian (GIN) Seas in a control integration of the HadCM3 coupled climate model. Interannual variability in sea surface temperature (SST) and sea surface salinity (SSS) is dominated by a quasi-periodic ∼7-year signal. Analyses show that the mechanism involves a competition between convection and advection. Advection carries cold, fresh, Arctic water over warm, salty, Atlantic water, while convection periodically mixes these two water masses vertically, raising SST. Convection is able to raise SST because of the presence of a subsurface temperature maximum. The GIN Seas convection in HadCM3 is forced by wind stress anomalies related to the North Atlantic Oscillation (NAO). The consequent SST anomalies feedback positively to force the atmosphere, resulting in a weak spectral peak (at ∼7 years) in GIN Seas sea level pressure. Although there is no evidence of a similar oscillation in reality, key aspects of the simulated mechanism may be relevant to understanding variability in the real GIN Seas. In particular, the potential for increases in convection to raise SST offers a possible new explanation for increases in SST that occurred between the 1960s and the late 1980s/early 1990s. These SST increases may have contributed to the observed sea-ice retreat. In addition, a positive feedback between GIN Seas SST and the atmosphere could contribute to the persistence of the NAO, potentially helping to explain its red spectrum or recent northeastward shift.

Sonia R. Gamiz-FortisEmail:

  相似文献   

Stratigraphy,age and petrography of the Beni Issef successions (External Rif; Morocco): Insights for the evolution of the Maghrebian Chain   总被引：1，自引：0，他引：1  

Angelida Di Staso  Vincenzo Perrone  Sonia Perrotta  Mohamed Najib Zaghloul  Michel Durand-Delga 《Comptes Rendus Geoscience》2010,342(9):718-730

In the Beni Issef Massif, nearly 30 km west of Chefchaouen (Morocco), the thickest post-nappe succession within the Rifian sector of the Maghrebian Chain seals the tectonic contact between the Intrarifian External Tanger and Loukkos Units, related to the Rifian External Domain. This succession is very important for the reconstruction of the deformation timing of the Rifian Maghrebids. The age of its base, in fact, is an important constraint for defining an upper boundary to the stacking of both the Intrarifian and Maghrebian Flysch Basin Units, because clasts fed by the Melloussa and Numidian Flysch Nappes are abundant in the conglomerate layers. Field and biostratigraphic analyses pointed out the presence of a Lower Beni Issef Fm, unconformable on the Intrarifian External Tanger and Loukkos Units, and an Upper Beni Issef Fm, unconformable on both the Intrarifian Units and the Lower Beni Issef Fm. The Lower Beni Issef Fm, 150 m thick, consists of lenticular conglomerates with huge blocks in a marly-clayey matrix, followed by marls and minor sandstones. It deposited in a siliciclastic platform, shows a fining upward trend and is affected by metre- to hectometre-sized, locally reversed, folds. Samples collected 45–50 m above the base of the formation resulted not older than Late Tortonian in age, but an older age for the base of the formation cannot be excluded. The Upper Beni Issef Fm, up to 550 m thick, starts with coarse conglomerates followed by medium- to coarse-grained well-bedded sandstones and by grey-blue marls and mudrocks. It indicates deposition in a channelized marine delta, with evolution towards pro-delta pelites, and shows sub-horizontal or gently dipping beds towards the east. Biostratigraphic data indicate a probable Messinian age for this formation. The composition of the arenites of both Lower Beni Issef and Upper Beni Issef Fms is quartzolithic and all samples show a notable content of monocrystalline well-rounded quartz and sedimentary lithic fragments. Detrital modes, all falling in the Quartzose Recycled and Transitional Recycled fields, suggest a provenance from recycling of sedimentary successions, easily recognizable in the Flysch Basin and External Units, mainly the Numidian Nappe sandstones. A Tortonian age of the Lower Beni Issef Fm would agree with the Late Serravallian age of the uppermost beds of the External Tanger Unit and indicate that the most probable age for the stacking of the Intrarifian Units falls in the Late Serravallian-Middle Tortonian time span. The Lower Beni Issef Fm was involved in a compressive tectonic phase testified by north-south striking folds. Later, probably during Messinian, the Upper Beni Issef Fm deposited in a younger intramontane basin, resting on both the Intrarifian Units and the Lower Beni Issef Fm. Successively, the Upper Beni Issef Fm was passively transported piggyback on top of the fold and thrust belt during later tectonic evolution of the Rifian Maghrebids. This tectonic evolution results quite similar to that recognized in the Tellian and Sicilian Maghrebids and also in the southern Apennines.  相似文献