Papers by Malavieille Jacques
Bulletin de la Société Géologique de France, 2002
In subduction zones undergoing oblique convergence, strain partitioning is often expressed by an ... more In subduction zones undergoing oblique convergence, strain partitioning is often expressed by an important deformation inducing strike-slip faulting. In accretionary wedges, parameters such as obliquity of the convergence and friction at the bottom of the wedge play an important role in the strain partitioning. The impact of these parameters is studied using sandbox experiments. Two backstop geometries have been designed to account for different geological settings. These experiments show that the wedge taper remains constant and close to αcoulomb for variable obliquities. Measurements of critical tapers on the models suggest that the Coulomb wedge theory cannot be simply applied to determine parameters on wedges developed under oblique convergence. Parameters deduced from this theory are valid only when measured in the direction parallel to the convergence. In addition, the partition degree increases with the obliquity of the convergence, and strain partitioning occurs independentl...
Marine Geophysical Researches, 1998
The Gagua Ridge, carried by the Philippine Sea Plate, is subducting obliquely beneath the souther... more The Gagua Ridge, carried by the Philippine Sea Plate, is subducting obliquely beneath the southernmost Ryukyu Margin. Bathymetric swath-mapping, performed during the ACT survey (Active Collision in Taiwan), indicates that, due to the high obliquity of plate convergence, slip partitioning occurs within the Ryukyu accretionary wedge. A transcurrent fault, trending N95° E, is observed at the rear of the accretionary wedge.
GSA Today, 2010
Interaction between surface and tectonic processes plays a key role in the structural evolution, ... more Interaction between surface and tectonic processes plays a key role in the structural evolution, kinematics, and exhumation of rocks in orogenic wedges. The deformation patterns observed in analog models show that strain partitioning has a strong impact on the vertical component of displacement of tectonic units, which in return favors erosion in domains of important uplift. Partitioning is controlled by tectonic processes and by climate-dependent surface processes, including erosion and sedimentation. The effects of partitioning include localization of deformed domains, exhumation above areas of deep underplating, and steady-state maintenance of wedges for long time periods. Simple models illustrate well how the morphostructural evolution of mountain belts is determined by these complex interactions. 1 GSA supplemental data item 2010039, additional information on geological background and modeling method, is
Tectonics, 1992
Sandbox modeling is used to study the deformation of accretionary wedges caused by the subduction... more Sandbox modeling is used to study the deformation of accretionary wedges caused by the subduction of oceanic ridges. The first experiment incorporates a massive ridge within a sand wedge. The wedge thickens and shortens when the forward propagation of the basal decollement ceases. The wedge thickening results in taper change, reactivation of preexisting thrusts, and retreat of the frontal part of the sand wedge. Similar mechanisms may have affected some margins that have undergone ridge subduction such as the Tonga margin after the subduction of the oblique Louisville oceanic ridge. The second experiment shows the effects of an active basement thrust slice as it enters a subduction zone. This process may have happened in the eastern Nankai accretionary wedge. Initially, the wedge in this experiment behaved similarly to that of the first experiment. Rapidly the topographic slope changed, the wedge thickened above the basement slice generating a slope break in the topography; a deeper...
Journal of Geophysical Research: Solid Earth, 2013
We recover the Holocene earthquake history of seven seismogenic normal faults in the Fucino syste... more We recover the Holocene earthquake history of seven seismogenic normal faults in the Fucino system, central Italy. We collected 800 samples from the well-preserved limestone scarps of the faults and modeled their 36 Cl concentrations to derive their seismic exhumation history. We found that > 30 large earthquakes broke the faults in synchrony over the last 12 ka. The seven faults released strain at the same periods of time, 12-9 ka, 5-3 ka, and 1.5-1 ka. On all faults, the strain accumulation and release occurred in 3-6 ka supercycles, each included a 3-5 ka phase of slow (≤ 0.5-2 mm/yr) strain accumulation in relative quiescence, followed by a cluster of three to four large earthquakes or earthquake sequences that released most of the strain in < 1-2 ka. The large earthquakes repeated every 0.5 ± 0.3 ka during the paroxysmal phases and every 4.3 ± 0.9 ka between those phases. Earthquakes on the northern faults produced twice larger surface slips (~2 m) and had larger magnitudes (Mw 6.2-6.7) than those on the southern faults. On most faults, the relative strain level was found to control the amount of slip and the time of occurrence of the next large earthquake. Faults entered a phase of clustered activity once they had reached a specific relative strain threshold. The Tre Monti fault is identified as the most prone to break over the next century. Our data document earthquake synchrony and clustering at a broader space and time scale than has been reported to date.
Geologische Rundschau, 1994
Geomorphology, 2015
Tectonically controlled landforms develop morphologic features that provide useful markers to inv... more Tectonically controlled landforms develop morphologic features that provide useful markers to investigate crustal deformation and relief growth dynamics. In this paper, we present results of morphotectonic experiments obtained with an innovative approach combining tectonic and surface processes (erosion, transport, and sedimentation), coupled with accurate model monitoring techniques. This approach allows for a qualitative and quantitative analysis of landscape evolution in response to active deformation in the three end-member geological settings: compression, extension, and strike-slip. Experimental results outline first that experimental morphologies evolve significantly at a short time scale. Numerous morphologic markers form continuously, but their lifetime is generally short because erosion and sedimentation processes tend to destroy or bury them. For the compressional setting, the formation of terraces above an active thrust appears mainly controlled by narrowing and incision of the main channel through the uplifting hanging-wall and by avulsion of deposits on fan-like bodies. Terrace formation is irregular even under steady tectonic rates and erosional conditions. Terrace deformation analysis allows retrieving the growth history of the structure and the fault slip rate evolution. For the extensional setting, the dynamics of hanging-wall sedimentary filling appears to control the position of the base level, which in turn controls footwall erosion. Two phases of relief evolution can be evidenced: the first is a phase of relief growth, and the second is a phase of upstream propagation of topographic equilibrium that is reached first in the sedimentary basin. During the phase of relief growth, the formation of triangular facets occurs by degradation of the fault scarp, and their geometry (height) becomes stationary during the phase of upstream propagation of the topographic equilibrium. For the strike-slip setting, the complex morphology of the wrench zone, composed of several interacting fault segments, enhances the interactions with the drainage network. Because of the widening of the main fault zone toward the surface, a significant amount of distributed deformation is observed along the wrench zone. Locally, where two terminations of fault segments interact, less than a quarter of the far field displacement can remain measurable using fault offsets, leading to a systematic underestimation of the real fault slip rate. These different experimental examples illustrate the great potential of the approach coupling deformation mechanisms and erosion-transport-sedimentation processes to investigate qualitatively and quantitatively the morphotectonic evolution of tectonically controlled landscapes.
International Journal of Earth Sciences, 2010
Abstract The Alps/Apennines system, as well as many collisional orogens through the world, shows ... more Abstract The Alps/Apennines system, as well as many collisional orogens through the world, shows a finite deformation produced during a long geological history which involves numerous superimposed tectonic events. As a result, complex and often contrasted reconstructions for the setting and tectonics of the different stages of the growing and interfering Alps/Apennines system have been proposed. To enlight some of the geometric and kinematic signatures related to past geodynamics in the composite Alps (Corsica)/ ...
Tectonophysics, 1998
In many active margins, severe deformation is observed at the front of the overriding plate where... more In many active margins, severe deformation is observed at the front of the overriding plate where seamounts or aseismic ridges subduct. Such deformation appears to be a main tectonic feature of these areas which influences the morphology and the seismicity of the margin. To better understand the different stages of seamount subduction, we have performed sandbox experiments to study in detail the evolution of deformation both in space and time and thus complement seismic images and bathymetry interpretation. We focus, in this paper, on the surface deformation directly comparable with seafloor morphology. Two types of subducting seamounts were modelled: relatively small conical seamounts, and larger flat-topped seamounts. The indentation of the margin by the seamount inhibits frontal accretion and produces a re-entrant. The margin uplift includes displacement along backthrusts which propagate from the base of the seamount, and out-of-sequence forethrusts which define a shadow zone located on the landward flank of the seamount. When the seamount is totally buried beneath the margin, this landward shielded zone disappears and a larger one is created in the wake of the asperity due to the elevated position of the décollement. As a consequence, a section of the margin front follows behind the seamount to greater depth. A 'slip-line' network develops concurrently above the subducting seamount flanks from the transtension along the boundaries of the shadow zone. In a final stage, normal faults, controlled by the shape of the seamount, develop in the subsiding wake of the asperity. Swath-bathymetric data from the Costa Rica margin reveal detailed surface deformation of the margin above three subducting seamounts. Shaded perspective views highlight the detailed structure of the seafloor and compare well with surface deformation in the sandbox experiments. The good correlation between the marine data and experimental results strengthen a structural interpretation of the Costa Rican seamount subduction.
Tectonophysics, 1990
Abstract A large-scale extensional shear zone is described from the Mont Pilat area in the northe... more Abstract A large-scale extensional shear zone is described from the Mont Pilat area in the northeastern part of the French Massif Central. This shear zone is about 2 km thick and is characterized by well-developed N-dipping foliation and stretching lineations. Deformation occurred under conditions of retrograde metamorphism from high-temperature conditions to greenschist facies. It is superimposed on a composite foliation related to the earlier Variscan (380-350 Ma) compressional events associated with southward emplacement of nappes ...
Tectonophysics, 2012
Abstract Experimental modelling applied to the study of orogenic wedge dynamics has been a subjec... more Abstract Experimental modelling applied to the study of orogenic wedge dynamics has been a subject of fruitful research for more than 30 years, although the technique dates back as far as the early XIX th century. On one hand, several first order parameters controlling the structural evolution of mountain belts have been intensively investigated using the classic tectonic&amp;amp;amp;amp;amp;quot; sandbox&amp;amp;amp;amp;amp;quot; models. The main parameters are the properties of the basal décollement, the deforming material, the backstop, and fluxes, kinematics and surface ...
Tectonophysics, 2011
We developed a new granular material (MatIV) to study experimentally landscape evolution in activ... more We developed a new granular material (MatIV) to study experimentally landscape evolution in active mountain belt piedmonts. Its composition and related physical properties have been determined using empirical criteria derived from the scaling of deformation, erosion-transport and sedimentation natural processes. MatIV is a water-saturated composite material made up with 4 granular components (silica powder, glass microbeads, plastic powder and graphite) whose physical, mechanical and erosion-related properties were measured with different laboratory tests. Mechanical measurements were made on a modified Hubberttype direct shear apparatus. Erosion-related properties were determined using an experimental setup that allows quantifying the erosion/sedimentation budget from tilted relaxation topographies. For MatIV, we also investigated the evolution of mean erosion rates and stream power erosion law exponents in 1D as a function of slope. Our results indicate that MatIV satisfies most of the defined criteria. It deforms brittlely according to the linear Mohr-Coulomb failure criterion and localizes deformation along discrete faults. Its erosion pattern is characterized by realistic hillslope and channelized processes (slope diffusion, mass wasting, channel incision). During transport, eroded particles are sorted depending on their density and shape, which results in stratified alluvial deposits displaying lateral facies variations. To evaluate the degree of similitude between model and nature, we used a new experimental device that combines accretionary wedge deformation mechanisms and surface runoff erosion processes. Results indicate that MatIV succeeded in producing detailed morphological and sedimentological features (drainage basin, channel network, terrace, syntectonic alluvial fan). Geometric, kinematic and dynamic similarity criteria have been investigated to compare precisely model to nature. Although scaling is incomplete, it yields particularly informative orders of magnitude. With all these characteristics, MatIV appears as a very promising material to investigate experimentally a wide range of scientific questions dealing with relief dynamics and interactions between tectonics, erosion and sedimentation processes.
Tectonophysics, 2012
The volume comprises some of the contributions presented during the 10th edition of the Alpine Me... more The volume comprises some of the contributions presented during the 10th edition of the Alpine Meeting "CorseAlp 2011". It has been held in Saint Florent (Corsica) between 10th and 16th of April 2011 under the auspices of Societe Geologique de France, Societa Geologica Italiana and the INGV (Istituto Nazionale di Geofisica e Vulcanologia) and with the collaboration of colleagues of Universite de Corse (M.-M. Spella, M. and J. Ferrandini and L. Ciancaleoni) and the support of the city council of S. Florent. The meeting was framed in the series of "Alpine Workshops" e.g., Siegesmund et al. (2008), Handy and Rosenberg (2011), which are held every two years to develop interdisciplinary research on Alpine-type orogens. It hosted a variety of topical sessions from regional geology to process-oriented field and laboratory studies and gave the opportunity to collect multidisciplinary and multiscale approaches to geodynamic studies including continental rifting and ocean opening, oceanic and continental subduction, late- to post orogenic extension, exhumation of deep seated rocks, back-arc opening and microcontinent rotation, interfering orogenic-scale tectonics and surface processes, tectonics and seismic hazard within the Alpine chain and Mediterranean realms.
Tectonics, 1999
Detailed seafloor mapping in the area east of Taiwan revealed trench‐parallel stretching and fold... more Detailed seafloor mapping in the area east of Taiwan revealed trench‐parallel stretching and folding of the Ryukyu forearc and lateral motion of the accretionary wedge under oblique convergence. East of 122°40′E, a steep accretionary wedge is elongated in an E–W direction. A major transcurrent right‐lateral strike‐slip fault accommodates the strain partitioning caused by an oblique convergence of 40°. A spectacular out‐of‐sequence thrust may be related to the subduction of a structural high lying in the axis of the N–S trending Gagua Ridge. This asperity is likely responsible for the uplift of the accretionary wedge and forearc basement and may have augmented strain partitioning by increasing the coupling between the two plates. West of 122°40′E, the low‐taper accretionary wedge is sheared in a direction subparallel to the convergence vector with respect to the Ryukyu Arc. The bayonet shape of the southern Ryukyu Arc slope partly results from the recent (re)opening of the southern O...
Tectonics, 2000
Sandbox experiments, using a two-dimensional and a three-dimensional approach, are used to study ... more Sandbox experiments, using a two-dimensional and a three-dimensional approach, are used to study the deformation of margins in response to seamount subduction. Successive mechanisms of deformation are activated during the subduction of conical seamounts. First, reactivation of the frontal thrusts and compaction of the accretionary wedge is observed. Then, back thrusting and, conjugate strike-slip faulting develops above the leading slope of the subducted seamount. The basal décollement is deflected upward in the wake of the subducting high, and a large shadow zone develops behind the seamount trailing slope. Consequently, frontal accretion is inhibited and part of the frontal margin is dragged into the subduction zone. When the main décollement returns to its basal level in the wake of the seamount, the margin records a rapid subsidence and a new accretionary wedge develops, closing the margin reentrant. The sediments underthrusted in the wake of the seamount into the shadow zone, are underplated beneath the rear part of the accretionary wedge. Substantial shortening and thickening of the deformable seaward termination of the upper plate basement, associated with basal erosion is observed. Seamount subduction induces significant material transfer within the accretionary wedge, favors large tectonic erosion of the frontal margin and thickening of the rear part of the margin. The subduction and underplating of relatively undeformed, water-ladden sediments, associated with fluid expulsion along the fractures affecting the margin could modify the fluid pressure along the basal décollement. Consequently, significant variations of the effective basal friction and local mechanical coupling between the two plates could be expected around the subducting seamount.
Marine Geology, 2002
Sandbox experiments of accretionary wedges were performed incorporating a thin weak layer of micr... more Sandbox experiments of accretionary wedges were performed incorporating a thin weak layer of micro glass beads. The impact of heterogeneous sedimentary input on wedge mechanics, evolution and mass transfer was investigated. We report the first experimentally documented growth of basal duplexes. These occurred for high basal friction conditions, with restricted output of the lower section. The upper and lower sections were completely decoupled due to the intervening layer of glass beads, with frontal accretion occurring in the upper section simultaneously with basal duplex formation and underplating of subsequent generations of duplexes. IMERSE multichannel seismic reflection data from the Western Mediterranean Ridge (WMR) image Tertiary clastics beneath a thick section of Messinian evaporites. The base of the evaporites is identified as the primary de ¤collement for deformation in the frontal part of the accretionary complex. Constriction of the channel of subducting Tertiary sediments, as well as internal deformation observed as arcward-dipping reflectors argue for basal underplating and/or two different active de ¤collements. We propose an evolution of the WMR in accordance with the sandbox experimental results. A weak mid-level detachment (base of evaporites) combined with a strong basal detachment produce mechanical decoupling and basal accretion of toeward-verging duplexes.
Journal of the Virtual Explorer, 2011
CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp ... more CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp field trips were designed to introduce the participants to the general features of the geology of Alpine Corsica and to recent specific discoveries. Field trip 1 focused on the geology of the Ocean-Continent Transition preserved in the Monte San Petrone, in Central Corsica, which was subducted to eclogite facies conditions during the Alpine orogeny. Field Guide 1 itinerary: Bastia, Golo Valley, Piedicroce, MS Petrone and S. Florent.
Journal of the Virtual Explorer, 2011
Corsica is located in the Mediterranean sea, about 90 km from the Italian coast of Tuscany and 17... more Corsica is located in the Mediterranean sea, about 90 km from the Italian coast of Tuscany and 175 km from the French Riviera. This relatively large island stretches for 180 km in the north-south direction and 85 Km east-west. The rugged landscape, with a mean elevation of ca. 500 m and the highest point at 2710 m (Monte Cinto) is interrupted only by a major plain along the east coast. CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp field trips were designed to introduce the participants to the ...
Journal of the Geological Society, 2013
Deformation mechanisms, long-term kinematics and evolution of fold and thrust belts submitted to ... more Deformation mechanisms, long-term kinematics and evolution of fold and thrust belts submitted to erosion are studied through 2D analog experiments involving large convergence. First order parameters tested include: i) décollements and/or plastic layers interbedded at different location within analog materials; ii) synconvergence surface erosion. Weak layers, depending on their location in the model, favor deformation partitioning characterized by the simultaneous development of: i) underplating domains in the inner part of the wedge (basal accretion); ii) frontal accretion where the wedge grows forward. Interaction between tectonics and surface processes influence this behavior. Development of antiformal thrust stacks controlled by underplating show small-and large-scale cyclicity. Thin plastic layers induce folding processes, which are studied at wedge scale. Recumbent and overturned folds, with large inverted limbs, develop in shear induced asymmetric deformation regime via progressive unrolling of synclinal hinges. Surface erosion and underplating at depth induce further rotation (passive tilting) and horizontalization of fold limbs. Models results give insights to discuss the mechanisms responsible for the large-scale structures (i.e., antiformal nappe stacks, klippen and kilometer scale recumbent foldnappes) encountered in several mountain belts such as the Montagne Noire (French Massif Central), the Galicia Variscan belt (Spain) or the Northern Apennines (Italy).
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Papers by Malavieille Jacques