Uso do bivalve límnico Anodontites tenebricosus (LEA, 1834) no biomonitoramento de metais do Rio Ribeira de Iguape

This study investigated the contamination of the Ribeira de Iguape River - RIR by Cd, Zn, Cr and Pb, using the bivalve Anodontites tenebricosus as a biomonitor. Metal concentrations in tissue samples were measured by HR-ICPMS. Bivalve tissues exhibited mean levels of 1.00 µg/g Cd; 152.89 µg/g Zn; 14.79 µg/g Cr and 4.40 µg/g Pb. Lead concentrations were comparable to those reported for moderately contaminated sites. The results showed that Pb is bioavailable to the bivalves, exhibiting high concentrations and exceeding both natural and reference values for human consumption. The freshwater bivalve Anodontites tenebricosus is a suitable biomonitor of contamination by metals.

Space-temporal dynamics of limnological variables in a floodplain wetland located at Ribeira do Iguape Valley (São Paulo, Brazil) at different hydrological periods

AIM: The main goal of this research was to investigate the influence of the hydrological pulses on the space-temporal dynamics of physical and chemical variables in a wetland adjacent to Jacupiranguinha River (São Paulo, Brazil); METHODS: Eleven sampling points were distributed among the wetland, a tributary by its left side and the adjacent river. Four samplings were carried out, covering the rainy and the dry periods. Measures of pH, dissolved oxygen, electrical conductivity and redox potential were taken in regular intervals of the water column using a multiparametric probe. Water samples were collected for the nitrogen and total phosphorus analysis, as well as their dissolved fractions (dissolved inorganic phosphorus, total dissolved phosphorus, ammoniacal nitrogen and nitrate). Total alkalinity and suspended solids were also quantified; RESULTS: The Multivariate Analysis of Variance showed the influence of the seasonality on the variability of the investigated variables, while the Principal Component Analysis gave rise in two statistical significant axes, which delimited two groups representative of the rainy and dry periods. Hydrological pulses from Jacupiranguinha River, besides contributing to the inputs of nutrients and sediments during the period of connectivity, accounted for the decrease in spatial gradients in the wetland. This "homogenization effect" was evidenced by the Cluster Analysis. The research also showed an industrial raw effluent as the main point source of phosphorus to the Jacupiranguinha River and, indirectly, to the wetland; CONCLUSIONS: Therefore, considering the scarcity of information about the wetlands in the study area, this research, besides contributing to the understanding of the influence of hydrological pulses on the investigated environmental variables, showed the need for adoption of conservation policies of these ecosystems face the increase anthropic pressures that they have been submitted, which may result in lack of their ecological, social and economic functions.

Minka - The houses of Japanese imigrants in Ribeira valley, São Paulo,Brazil

O artigo analisa o processo de produção de moradia do imigrante japonês no Vale do Ribeira, na região sul do estado de São Paulo, ocorrido no início do século XX. Partindo do contexto histórico do início da colonização da região e as condicionantes que possibilitaram a criação da colônia, o trabalho busca verificar como foram construídas as casas que, baseados na autoconstrução e tendo a terra e madeira formaram o repertório de quase 500 casas. Põe foco em dois exemplares onde são analisadas a técnica do tsuchikabe e as sambladuras; verificando que mesmo diante das adversidades encontradas na natureza distinta de sua origem construíram casas de elevada qualidade. Os saberes trazidos do extremo oriente foram aplicados e se mesclaram às influências, cabocla, quilombola e europeia que hoje, após um século, representam uma categoria expressiva e variada sob os aspectos construtivo, tipológico e programático.

On the three-finger protein domain fold and CD59-like proteins in Schistosoma mansoni

Background: It is believed that schistosomes evade complement-mediated killing by expressing regulatory proteins on their surface. Recently, six homologues of human CD59, an important inhibitor of the complement system membrane attack complex, were identified in the schistosome genome. Therefore, it is important to investigate whether these molecules could act as CD59-like complement inhibitors in schistosomes as part of an immune evasion strategy. Methodology/Principal Findings: Herein, we describe the molecular characterization of seven putative SmCD59-like genes and attempt to address the putative biological function of two isoforms. Superimposition analysis of the 3D structure of hCD59 and schistosome sequences revealed that they contain the three-fingered protein domain (TFPD). However, the conserved amino acid residues involved in complement recognition in mammals could not be identified. Real-time RT-PCR and Western blot analysis determined that most of these genes are up-regulated in the transition from free-living cercaria to adult worm stage. Immunolocalization experiments and tegument preparations confirm that at least some of the SmCD59-like proteins are surface-localized; however, significant expression was also detected in internal tissues of adult worms. Finally, the involvement of two SmCD59 proteins in complement inhibition was evaluated by three different approaches: (i) a hemolytic assay using recombinant soluble forms expressed in Pichia pastoris and E. coli; (ii) complement-resistance of CHO cells expressing the respective membrane-anchored proteins; and (iii) the complement killing of schistosomula after gene suppression by RNAi. Our data indicated that these proteins are not involved in the regulation of complement activation. Conclusions: Our results suggest that this group of proteins belongs to the TFPD superfamily. Their expression is associated to intra-host stages, present in the tegument surface, and also in intra-parasite tissues. Three distinct approaches using SmCD59 proteins to inhibit complement strongly suggested that these proteins are not complement inhibitors and their function in schistosomes remains to be determined.

Le Bassin de Ribeira Seca de Santiago, Cap Vert: une gestion basée sur l'approche GIRE

[FR] Dans cet article, l´auteur caractérise l´eau et l´agriculture des îles du Cap Vert et analyse les défis de l´eau après la construction du barrage de Poilao dans la Vallée de Ribeira Seca, sur l´île de Santiago, en se servant de l´approche GIRE (Gestion Intégrée des Ressources en Eau). Au niveau de la législation, il s´avère nécessaire de proposer de nouvelles lois, décrets et règlements qui soient en accord avec notre réalité, en opposition à un important lot d´instruments juridiques inapplicables, obsolètes et de compréhension difficile. La construction du barrage de Poilão a produit des impacts environnementaux, socio-économiques et sur l´irrigation. Il s´agit de trouver un modèle de gestion qui s´adapte à la réalité du Cap Vert et de l´île de Santiago, regroupant tous les partenaires pour une gestion durable de la vallée de Ribeira Seca et qui puisse servir d´exemple aux futurs barrages à construire.

Eocene nappe tectonics and late Alpine extension in the Central Anatolide belt, western Turkey

Strukturgeologische Untersuchungen belegen, daß die Anatoliden der Westtürkei im Eozän durch die Plazierung der Kykladischen Blauschiefereinheit entlang einer durchbrechenden Überschiebung auf die Menderes-Decken unter grünschieferfaziellen Metamorphosebedingungen entstanden.Die kykladischen Blauschiefer in der Westtürkei enthalten Relikte eines prograden alpinen Gefüges (DA1), welches hochruckmetamorph von Disthen und Chloritoid poikiloblastisch überwachsen wurde. Dieses Mineralstadium dauerte noch während des Beginns des nachfolgenden Deformationsereignisses (DA2) an, welches durch NE-gerichtete Scherung und Dekompression charakterisiert ist. Die nachfolgende Deformation (DA3) war das erste Ereignis, das beide Einheiten, sowohl die kykladische Blauschifereinheit als auch die Menderes-Decken, gemeinsam erfaßte. Der Überschiebungskontakt zwischen der kykladischen Blauschiefereinheit und den Menderes-Decken ist eine DA3-Scherzone: die ‘Cycladic-Menderes Thrust’ (CMT). Entlang der CMT-Überschiebungsbahn wurden die kykladischen Blauschiefer gegen veschiedene Einheiten der MN plaziert. Die CMT steigt nach S zum strukturell Hangenden hin an und kann daher als eine durchbrechende Überschiebung entlang einer nach S ansteigenden Rampe betrachtet werden. In den kykladischen Blauschiefern überprägen DA3-Strukturen, die im Zusammenhang mit der CMT stehen, hochdruckmentamorphe Gefüge.In den Menderes-Decken, dem Liegenden der CMT, wird DA3 durch regional vebreitete Gefügeelemente dokumentiert, die im Zusammenhang mit S-gerichteten Schersinnindikatoren stehen. DA3-Gefüge haben die Decken intern deformiert und bilden jene Scherzonen, welche die Decken untereinander abgrenzen. In der Çine-Decke können granitische Gesteine in Orthogneise und Metagranite unterteilt werden. Die Deformationsgeschichte dieser Gesteine dokumentiert zwei Ereignisse. Ein frühes amphibolitfazielles Ereignis erfaßte nur die Orthogneise, in denen vorwiegend NE-SW orientierte Lineare und NE-gerichtete Schersinnindikatoren entstanden. Die jüngeren Metagranite wurden sowohl durch vereinzelte DA3-Scherzonen, als auch in einer großmaßstäblichen DA3-Scherzone am Südrand des Çine-Massivs deformiert. In DA3-Scherzonen sind die Lineare N-S orientiert und die zugehörigen Schersinnindikatoren zeigen S-gerichtete Scherung unter grünschieferfaziellen Bedingungen an. Diese grünschieferfaziellen Scherzonen überprägen die amphibolitfaziellen Gefüge in den Orthogneisen. Magmatische Zirkone aus einem Metagranit, der einen Orthogneiss mit Top-NE Gefügen durchschlägt, ergaben ein 207Pb/206Pb-Alter von 547,2±1,0 Ma. Dies deutet darauf hin, daß DPA proterozoischen Alters ist. Dies wird auch durch die Tatsache gestützt, daß triassische Granite in der Çine- und der Bozdag-Decke keine DPA-Gefüge zeigen. Die jüngeren Top-S-Gefüge sind wahrscheinlich zur gleichen Zeit entstanden wie die ältesten Gefüge der Bayindir-Decke.Das Fehlen von Hochdruck-Gefügen im Liegenden der CMT impliziert eine Exhumierung der kykladischen Blauschiefer von mehr ca. 35 km, bevor diese im Eozän auf die Menderes-Decken aufgeschoben wurden. Die substantiellen Unterschiede bezüglich in der tektonometamorphen Geschichte der kykladischen Blauschiefer und der Menderes-Decken widersprechen der Modellvorstellung eines lateral kontinuierlichen Orogengürtels, nach der die Menderes-Decken als östliche Fortsezung der kykladischen Blauschiefer angesehen werden.Die Analyse spröder spätalpiner Deformationsstrukturen und das regionale Muster mit Hilfe von Spaltspurdatierung modellierter Abkühlalter deuten darauf hin, daß die Struktur des Eozänen Deckenstapels durch miozäne bis rezente Kernkomplex-Bildung stark modifiziert wurde. Eine großmaßstäbliche Muldenstruktur im zentralen Teil der Anatoliden hat sich als Folge zweier symmetrisch angeordneter Detachment-Systeme von initial steilen zu heute flachen Orientierungen im Einflußbreich von ’Rolling Hinges’ gebildet. Die Detachment-Störungen begrenzen den ‘Central Menderes metamorphic core complex’ (CMCC). Das Muster der Apatit-Spaltspuralter belegt, daß die Bildung des CMCC im Miozän begann. Durch die Rück-Deformierung von parallel zur Foliation konstruierten Linien gleicher Abkühlalter kann gezeigt werden, daß die Aufwölbung im Liegenden der Detachments zur Entstehung der Muldenstruktur führte. Das hohe topographische Relief im Bereich des CMCC ist eine Folge der Detachment-Störungen, was darauf hindeutet daß der obere Mantel in den Prozeß mit einbezogen gewesen ist.

Geochronological and structural evolution of the western and central Kaoko Belt in NW Namibia

This thesis focusses on the tectonic evolution and geochronology of part of the Kaoko orogen, which is part of a network of Pan-African orogenic belts in NW Namibia. By combining geochemical, isotopic and structural analysis, the aim was to gain more information about how and when the Kaoko Belt formed. The first chapter gives a general overview of the studied area and the second one describes the basis of the Electron Probe Microanalysis dating method. The reworking of Palaeo- to Mesoproterozoic basement during the Pan-African orogeny as part of the assembly of West Gondwana is discussed in Chapter 3. In the study area, high-grade rocks occupy a large area, and the belt is marked by several large-scale structural discontinuities. The two major discontinuities, the Sesfontein Thrust (ST) and the Puros Shear Zone (PSZ), subdivide the orogen into three tectonic units: the Eastern Kaoko Zone (EKZ), the Central Kaoko Zone (CKZ) and the Western Kaoko Zone (WKZ). An important lineament, the Village Mylonite Zone (VMZ), has been identified in the WKZ. Since plutonic rocks play an important role in understanding the evolution of a mountain belt, zircons from granitoid gneisses were dated by conventional U-Pb, SHRIMP and Pb-Pb techniques to identify different age provinces. Four different age provinces were recognized within the Central and Western part of the belt, which occur in different structural positions. The VMZ seems to mark the limit between Pan-African granitic rocks east of the lineament and Palaeo- to Mesoproterozoic basement to the west. In Chapter 4 the tectonic processes are discussed that led to the Neoproterozoic architecture of the orogen. The data suggest that the Kaoko Belt experienced three main phases of deformation, D1-D3, during the Pan-African orogeny. Early structures in the central part of the study area indicate that the initial stage of collision was governed by underthrusting of the medium-grade Central Kaoko zone below the high-grade Western Kaoko zone, resulting in the development of an inverted metamorphic gradient. The early structures were overprinted by a second phase D2, which was associated with the development of the PSZ and extensive partial melting and intrusion of ~550 Ma granitic bodies in the high-grade WKZ. Transcurrent deformation continued during cooling of the entire belt, giving rise to the localized low-temperature VMZ that separates a segment of elevated Mesoproterozoic basement from the rest of the Western zone in which only Pan-African ages have so far been observed. The data suggest that the boundary between the Western and Central Kaoko zones represents a modified thrust zone, controlling the tectonic evolution of the Kaoko belt. The geodynamic evolution and the processes that generated this belt system are discussed in Chapter 5. Nd mean crustal residence ages of granitoid rocks permit subdivision of the belt into four provinces. Province I is characterised by mean crustal residence ages <1.7 Ga and is restricted to the Neoproterozoic granitoids. A wide range of initial Sr isotopic values (87Sr/86Sri = 0.7075 to 0.7225) suggests heterogeneous sources for these granitoids. The second province consists of Mesoproterozoic (1516-1448 Ma) and late Palaeo-proterozoic (1776-1701 Ma) rocks and is probably related to the Eburnian cycle with Nd model ages of 1.8-2.2 Ga. The eNd i values of these granitoids are around zero and suggest a predominantly juvenile source. Late Archaean and middle Palaeoproterozoic rocks with model ages of 2.5 to 2.8 Ga make up Province III in the central part of the belt and are distinct from two early Proterozoic samples taken near the PSZ which show even older TDM ages of ~3.3 Ga (Province IV). There is no clear geological evidence for the involvement of oceanic lithosphere in the formation of the Kaoko-Dom Feliciano orogen. Chapter 6 presents the results of isotopic analyses of garnet porphyroblasts from high-grade meta-igneous and metasedimentary rocks of the sillimanite-K-feldspar zone. Minimum P-T conditions for peak metamorphism were calculated at 731±10 °C at 6.7±1.2 kbar, substantially lower than those previously reported. A Sm-Nd garnet-whole rock errorchron obtained on a single meta-igneous rock yielded an unexpectedly old age of 692±13 Ma, which is interpreted as an inherited metamorphic age reflecting an early Pan-African granulite-facies event. The dated garnets survived a younger high-grade metamorphism that occurred between ca. 570 and 520 Ma and apparently maintained their old Sm-Nd isotopic systematics, implying that the closure temperature for garnet in this sample was higher than 730 °C. The metamorphic peak of the younger event was dated by electronmicroprobe on monazite at 567±5 Ma. From a regional viewpoint, it is possible that these granulites of igneous origin may be unrelated to the early Pan-African metamorphic evolution of the Kaoko Belt and may represent a previously unrecognised exotic terrane.

Deep geometry of subduction below the Andean belt of Colombia as revealed by seismic tomography

In this study new tomographic models of Colombia were calculated. I used the seismicity recorded by the Colombian seismic network during the period 2006-2009. In this time period, the improvement of the seismic network yields more stable hypocentral results with respect to older data set and allows to compute new 3D Vp and Vp/Vs models. The final dataset consists of 10813 P- and 8614 S-arrival times associated to 1405 earthquakes. Tests with synthetic data and resolution analysis indicate that velocity models are well constrained in central, western and southwestern Colombia to a depth of 160 km; the resolution is poor in the northern Colombia and close to Venezuela due to a lack of seismic stations and seismicity. The tomographic models and the relocated seismicity indicate the existence of E-SE subducting Nazca lithosphere beneath central and southern Colombia. The North-South changes in Wadati-Benioff zone, Vp & Vp/Vs pattern and volcanism, show that the downgoing plate is segmented by slab tears E-W directed, suggesting the presence of three sectors. Earthquakes in the northernmost sector represent most of the Colombian seimicity and concentrated on 100-170 km depth interval, beneath the Eastern Cordillera. Here a massive dehydration is inferred, resulting from a delay in the eclogitization of a thickened oceanic crust in a flat-subduction geometry. In this sector a cluster of intermediate-depth seismicity (Bucaramanga Nest) is present beneath the elbow of the Eastern Cordillera, interpreted as the result of massive and highly localized dehydration phenomenon caused by a hyper-hydrous oceanic crust. The central and southern sectors, although different in Vp pattern show, conversely, a continuous, steep and more homogeneous Wadati-Benioff zone with overlying volcanic areas. Here a "normalthickened" oceanic crust is inferred, allowing for a gradual and continuous metamorphic reactions to take place with depth, enabling the fluid migration towards the mantle wedge.

The effect of osmolytes on protein fold stability at the single-molecule level

By pulling and releasing the tension on protein homomers with the Atomic Force Miscroscope (AFM) at different pulling speeds, dwell times and dwell distances, the observed force-response of the protein can be fitted with suitable theoretical models. In this respect we developed mathematical procedures and open-source computer codes for driving such experiments and fitting Bell’s model to experimental protein unfolding forces and protein folding frequencies. We applied the above techniques to the study of proteins GB1 (the B1 IgG-binding domain of protein G from Streptococcus) and I27 (a module of human cardiac titin) in aqueous solutions of protecting osmolytes such as dimethyl sulfoxide (DMSO), glycerol and trimethylamine N-oxide (TMAO). In order to get a molecular understanding of the experimental results we developed an Ising-like model for proteins that incorporates the osmophobic nature of their backbone. The model benefits from analytical thermodynamics and kinetics amenable to Monte-Carlo simulation. The prevailing view used to be that small protecting osmolytes bridge the separating beta-strands of proteins with mechanical resistance, presumably shifting the transition state to significantly higher distances that correlate with the molecular size of the osmolyte molecules. Our experiments showed instead that protecting osmolytes slow down protein unfolding and speed-up protein folding at physiological pH without shifting the protein transition state on the mechanical reaction coordinate. Together with the theoretical results of the Ising-model, our results lend support to the osmophobic theory according to which osmolyte stabilisation is a result of the preferential exclusion of the osmolyte molecules from the protein backbone. The results obtained during this thesis work have markedly improved our understanding of the strategy selected by Nature to strengthen protein stability in hostile environments, shifting the focus from hypothetical protein-osmolyte interactions to the more general mechanism based on the osmophobicity of the protein backbone.

Neoproterozoic to middle Palaeozoic evolution of the Central Asian Orogenic Belt in south-central Mongolia: chronological and geochemical perspectives

Mongolia occupies a central position within the eastern branch of the large accretionary Central Asian Orogenic Belt (CAOB) or Altaids. The present work aims to outline the geodynamic environment and possible evolution of this part of the eastern CAOB, predominantly from the Cambrian to the middle Palaeozoic. The investigation primarily focussed on zircon geochronology as well as whole-rock geochemical and Sm–Nd isotopic analyses for a variety of metaigneous rocks from the southern Hangay and Gobi-Altai regions in south-central Mongolia. The southern slope of the Hangay Mountains in central Mongolia exposes a large NWSE-trending middle Neoproterozoic ophiolitic complex (c. 650 Ma), which is tectonically integrated within an accretionary complex developed between the Precambrian Baydrag and Hangay crustal blocks. Formation of the entire accretionary system along the north-eastern margin of the Baydrag block mainly occurred during the early Cambrian, but convergence within this orogenic zone continued until the early Ordovician, because of on-going southward subduction-accretion of the Baydrag block. An important discovery is the identification of a late Mesoproterozoic to early Neoproterozoic belt within the northern Gobi-Altai that was reworked during the late Cambrian and throughout the late Ordovician/Devonian. Early Silurian low-grade mafic and felsic metavolcanic rocks from the northern Gobi-Altai display subduction-related geochemical features and highly heterogeneous Nd isotopic compositions, which suggest an origin at a mature active continental margin. Early Devonian protoliths of granodioritic and mafic gneisses from the southern Gobi-Altai display geochemical and Nd isotopic compositions compatible with derivation and evolution from predominantly juvenile crustal and mantel sources and these rocks may have been emplaced within the outboard portion of the late Ordovician/early Silurian active continental margin. Moreover, middle Devonian low-grade metavolcanic rocks from the southwestern Gobi-Altai yielded geochemical and Nd isotopic data consistent with emplacement in a transitional arc-backarc setting. The combined U–Pb zircon ages and geochemical data obtained from the Gobi-Altai region suggest that magmatism across an active continental margin migrated oceanwards through time by way of subduction zone retreat throughout the Devonian. Progressive extension of the continental margin was associated with the opening of a backarc basin and culminated in the late Devonian with the formation of a Japan-type arc front facing a southward open oceanic realm (present-day coordinates).

Characterization of fold-related fractures in the carbonate rocks of the Cingoli anticline, northern Apennines, Italy

Thrust fault-related folds in carbonate rocks are characterized by deformation accommodated by different structures, such as joints, faults, pressure solution seams, and deformation bands. Defining the development of fracture systems related to the folding process is significant both for theoretical and practical purposes. Fracture systems are useful constrains in order to understand the kinematical evolution of the fold. Furthermore, understanding the relationships between folding and fracturing provides a noteworthy contribution for reconstructing the geodynamic and the structural evolution of the studied area. Moreover, as fold-related fractures influence fluid flow through rocks, fracture systems are relevant for energy production (geothermal studies, methane and CO2 , storage and hydrocarbon exploration), environmental and social issues (pollutant distribution, aquifer characterization). The PhD project shows results of a study carried out in a multilayer carbonate anticline characterized by different mechanical properties. The aim of this study is to understand the factors which influence the fracture formation and to define their temporal sequence during the folding process. The studied are is located in the Cingoli anticline (Northern Apennines), which is characterized by a pelagic multilayer characterized by sequences with different mechanical stratigraphies. A multi-scale analysis has been made in several outcrops located in different structural positions. This project shows that the conceptual sketches proposed in literature and the strain distribution models outline well the geometrical orientation of most of the set of fractures observed in the Cingoli anticline. On the other hand, the present work suggests the relevance of the mechanical stratigraphy in particular controlling the type of fractures formed (e.g. pressure solution seams, joints or shear fractures) and their subsequent evolution. Through a multi-scale analysis, and on the basis of the temporal relationship between fracture sets and their orientation respect layering, I also suggest a conceptual model for fracture systems formation.

Understanding block rotation of strike-slip fault zones: Paleomagnetic and structural approach

This thesis is focused on the paleomagnetic rotation pattern inside the deforming zone of strike-slip faults, and the kinematics and geodynamics describing it. The paleomagnetic investigation carried out along both the LOFZ and the fore-arc sliver (38º-42ºS, southern Chile) revealed an asymmetric rotation pattern. East of the LOFZ and adjacent to it, rotations are up to 170° clockwise (CW) and fade out ~10 km east of fault. West of the LOFZ at 42ºS (Chiloé Island) and around 39°S (Villarrica domain) systematic CCW rotations have been observed, while at 40°-41°S (Ranco-Osorno domain) and adjacent to the LOFZ CW rotations reach up to 136° before evolving to CCW rotations at ~30 km from the fault. These data suggest a directed relation with subduction interface plate coupling. Zones of high coupling yield to a wide deforming zone (~30 km) west of the LOFZ characterized by CW rotations. Low coupling implies a weak LOFZ and a fore-arc dominated by CCW rotations related to NW-sinistral fault kinematics. The rotation pattern is consistent with a quasi-continuous crust kinematics. However, it seems unlikely that the lower crust flux can control block rotation in the upper crust, considering the cold and thick fore-arc crust. I suggest that rotations are consequence of forces applied directly on both the block edges and along the main fault, within the upper crust. Farther south, at the Austral Andes (54°S) I measured the anisotropy of magnetic susceptibility (AMS) of 22 Upper Cretaceous to Upper Eocene sites from the Magallanes fold-thrust belt internal domains. The data document continuous compression from the Early Cretaceous until the Late Oligocene. AMS data also show that the tectonic inversion of Jurassic extensional faults during the Late Cretaceous compressive phase may have controlled the Cenozoic kinematic evolution of the Magallanes fold-thrust belt, yielding slip partitioning.

2D and 3D numerical modelling of multilayer detachment folding and salt tectonics

Numerical modelling was performed to study the dynamics of multilayer detachment folding and salt tectonics. In the case of multilayer detachment folding, analytically derived diagrams show several folding modes, half of which are applicable to crustal scale folding. 3D numerical simulations are in agreement with 2D predictions, yet fold interactions result in complex fold patterns. Pre-existing salt diapirs change folding patterns as they localize the initial deformation. If diapir spacing is much smaller than the dominant folding wavelength, diapirs appear in fold synclines or limbs.rnNumerical models of 3D down-building diapirism show that sedimentation rate controls whether diapirs will form and influences the overall patterns of diapirism. Numerical codes were used to retrodeform modelled salt diapirs. Reverse modelling can retrieve the initial geometries of a 2D Rayleigh-Taylor instability with non-linear rheologies. Although intermediate geometries of down-built diapirs are retrieved, forward and reverse modelling solutions deviate. rnFinally, the dynamics of fold-and-thrusts belts formed over a tilted viscous detachment is studied and it is demonstrated that mechanical stratigraphy has an impact on the deformation style, switching from thrust- to folding-dominated. The basal angle of the detachment controls the deformation sequence of the fold-and-thrust belt and results are consistent with critical wedge theory.rn