Melody Philippon

Université des Antilles | Reunion · Department of Geology

In this study, alternatively to the megathrust, we identify upper plate normal faults orthogonal to the trench as a possible tsunami source along the Lesser Antilles subduction zone. We study the Morne Piton Fault system, a trench-perpendicular upper crustal fault affecting the Lesser Antilles forearc at the latitude of Guadeloupe. By the means of...

Seismic hazard levels used as reference for the French Lesser Antilles are derived from probabilistic seismic hazard assessment studies performed in 2002. However, scientific knowledge has greatly increased over the past 20 years in this area, warranting an update of the seismic hazard models. As part of a project linking the French Ministry of Eco...

Relative Caribbean‐North American plate motion is partitioned over the trench and intra‐Caribbean plate faults that bound large scale tectonic blocks. Quantifying the kinematic evolution of this tectonic corridor is challenging because much of the region is submarine. We present an extensive regional paleomagnetic data set (1,330 cores from 136 sam...

Phylogenetic studies of present-day terrestrial organisms suggest that faunal dispersals between South America and the Greater Antilles may have occurred during the Cenozoic through the Lesser Antilles. However, because of the lack of geological data to unravel the areas that may have emerged along the Lesser Antilles trench, the migration paths us...

Since the acceptance of plate tectonics, the presence of calc-alkaline magmatic rocks has been recognized as evidence of subduction. But under specific geodynamic circumstances, subduction may occur without generating magmas. Here, we investigate the Cenozoic northern Lesser Antilles arc where, from sparsely exposed magmatic records, Eocene−Oligoce...

This study presents an extensive geochemical data set of 23 samples from St. Barthélemy Island, which belongs to the extinct branch of the Lesser Antilles arc and is currently exposed in the northern part of the subduction forearc. Samples were selected to represent all lithologies and main periods of magmatism, that is, Middle‐Late Eocene, Early O...

A new data set combining thermobarometry, geo‐thermochronology, chronostratigraphic, and structural analyses highlights the tectono‐thermal evolution of the St. Martin granodiorite from its emplacement to its surface exposure. The described vertical motions in this part of the upper plate of the Lesser Antilles subduction zone since 30 Myrs are lin...

The continental shelf north of Central Venezuela is partially or completely structurally controlled by major right lateral strike slip active faults (e.g. San Sebastián fault), comprising three physiographic provinces, from west to east: The Golfo Triste Platform, the Choroní Basin and the La Guaira Platform. The two mentioned platforms are of eros...

The Eocene tectonic evolution of the easternmost Caribbean Plate (CP) boundary, that is the Lesser Antilles subduction zone (LASZ), is debated. Recents works shed light on a peculiar period of tectonic duality in the arc/back‐arc regions. A compressional‐to‐transpressional regime occurred in the north, while rifting and seafloor spreading occurred...

The West Indies are a natural laboratory for the study of biogeography and evolution, especially for mammals. The modality of their arrival in the Caribbean islands is a highly controversial issue, and palaeontological evidence remains particularly elusive. Lower Oligocene deposits of Puerto Rico (c. 29.5 Ma) have recently yielded the oldest archip...

The Eocene tectonic evolution of the easternmost Caribbean Plate (CP) boundary, i.e. the Lesser Antilles subduction zone (LASZ), is debated. Recents works shed light on a peculiar period of tectonic duality in the arc/back-arc regions. A compressive-to-transpressive regime occurred in the north, while rifting and seafloor spreading occurred in Gren...

Our study aims to reconstruct the palaeogeography of the northern part of the Lesser Antilles in order to analyse whether emerged areas might have existed during the Cenozoic, favouring terrestrial faunal dispersals between South America and the Greater Antilles along the present-day Lesser Antilles arc. The stratigraphy and depositional environmen...

Oblique collision of buoyant provinces against subduction zones frequently results in individualizing and rotating regional‐scale blocks. In contrast, the collision of the Bahamas Bank against the Northeastern Caribbean Plate increased the margin convexity triggering forearc fragmentation into small‐scale blocks. This deformation results in a promi...

[This corrects the article DOI: 10.1371/journal.pone.0241000.].

The brittle deformation of internal zones of the Rif chain, corresponding to the southern margin of the West Alboran Basin, is not or poorly dated because of the lack of stratigraphic constraints. We provide for the first time a direct dating of brittle deformation of internal zones of the Rif chain, in the Ceuta peninsula located in the westernmos...

The Grenada Basin separates the active Lesser Antilles Arc from the Aves Ridge, described as a Cretaceous‐Paleocene remnant of the “Great Arc of the Caribbean.” Although various tectonic models have been proposed for the opening of the Grenada Basin, the data on which they rely are insufficient to reach definitive conclusions. This study presents,...

Intriguing latest Eocene land-faunal dispersals between South America and the Greater Antilles (northern Caribbean) has inspired the hypothesis of the GAARlandia (Greater Antil-les Aves Ridge) land bridge. This landbridge, however, should have crossed the Caribbean oceanic plate, and the geological evolution of its rise and demise, or its geodynami...

By their past and present diversity, rodents are among the richest components of Caribbean land mammals. Their phylogenetic affinities, the timing of their arrival in the West Indies, and their biogeographical history are all ongoing debated issues. Here we report the discovery of rodent teeth from lower Oligocene deposits (~29.5 Ma) of Puerto Rico...

In order to decipher the tectono-metamorphic evolution of shallow crustal levels of the active volcanic arc of the Guadeloupe archipelago (Lesser Antilles) we present new geochemical, geochronological, mineralogical and structural investigations of the so-called Basal Complex, the oldest and most eroded volcanic complex of Basse-Terre in Guadeloupe...

As part of the GEOTREF research project, a cost-effective approach, relying on innovative software tools, is proposed to carry out prefeasibility studies prior drilling based on numerical conceptual models associated with phenomenological modelling and well layout optimization. The numerical conceptual models are intended to be 3D structural, geolo...

This study investigates the Lesser Antilles fore-arc at the latitude of Guadeloupe Archipelago and evidences that La Désirade Island, the eastermost island of the forearc, displays a staircase coastal sequence including four uplifted marine terraces and an upper reefal platform with mean shoreline angle elevations ranging from 10 to 210 m above sea...

The sedimentary model of coastal deposits in eastern Rhodes over the last 2 Ma is refined and improved in accuracy. New field investigations and U/Th dating of Spondylus bivalve shells, combined with micropalaeontological and sedimentological data, allow the recognition of four synthems separated by major erosional surfaces. We present here evidenc...

We unravel for the first time the expression of a low-grade metamorphic event affecting the deepest exposures of the Guadeloupe Island, central Lesser Antilles, Caribbean plate. The work offers a novel insight for the presence of young (<3 Ma) sub-greenschist facies metamorphism in the Lesser Antilles active arc and is consistent with the elevated...

The upper plate deformation pattern reflects the mechanical behavior of subduction zones. Here we focus on the consequences of the entrance of a buoyant bank into the Caribbean subduction zone during the Eocene by studying the oldest exposed rocks belonging to the Lesser Antilles volcanic arc. Using a novel geochronological data set, we show that t...

We present a regional model of plate geometry and kinematics of southeast Asia since the Late Cretaceous, embedded in a global plate model. The model involves subduction polarity reversals and sheds new light on the origin of the subduction polarity reversal presently observed in Taiwan. We show that this subduction zone reversal is inherited from...

Trench-parallel strike slip faults develop at lithospheric scale during oblique high-angle subduction. A “sliver” plate forms due to slip partitioning between the subduction plane (margin-normal slip) and the strike slip fault (margin-parallel slip). This process ultimately controls the location of volcanoes and earthquakes. The Great Sumatran Faul...

Lithospheric-scale faults related to oblique subduction are responsible for some of the most hazardous earthquakes reported worldwide. The mega-thrust in the Sunda sector of the Sumatran oblique subduction has been intensively studied, especially after the infamous 2004 Mw 9.1 earthquake, but its onshore kinematic complement within the Sumatran sub...

Aegean extension is a process driven by slab rollback that, since 45 Ma, shows a twostage evolution. From Middle Eocene to Middle Miocene it is accommodated by localized deformation leading to i) the exhumation of high-pressure metamorphic rocks from mantle to crustal depths, ii) the exhumation of high-temperature rocks in core complexes and iii) t...

The long-lived Andean subduction zone underwent several flat slab episodes and is therefore ideal to study the consequences of a complete cycle of slab flattening and steepening on the upper plate deformation pattern. In the modern Peruvian forearc (15°-17°S), slab flattening caused a Paleogene (52-30 Ma) landward migration of volcanic activity. Co...

In this study, we investigate the Lesser Antilles forearc basin, focusing on the late Pliocene to Pleistocene sedimentary archives in order to track the occurrence of extreme events triggered by enhanced subduction-related tectono-volcanic activity. We identify late Piacenzian deposits covering a major regional erosional surface, displaying sedimen...

L'Est de la plaque Caraïbe est délimité depuis le Crétacé par une zone de subduction à vergence Ouest. Du Paléocène à l'Eocène l'entrée en subduction du banc des Bahamas entraine le réarrangement de la frontière de plaques qui est suivi de la mise en place de l'arc des Petites Antilles. Au sud des Petites Antilles l'activité magmatique de cet arc e...

Despite a long history of plate convergence at the western margin of the South American plate that has been ongoing since at least the Early Paleozoic, the southern Peruvian fore-arc displays little to no evidence of shortening. In the light of this observation, we assess the deformation history of the southern Peruvian fore-arc and its geodynamic...

We present a regional model of plate geometry and kinematics of Southeast Asia since the Late Cretaceous, embedded in a global plate model. The model involves subduction polarity reversals and sheds new light on the origin of the subduction polarity reversal currently observed in Taiwan. We show that this subduction zone reversal is inherited from...

Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundary total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within...

Back-arc extension in the Aegean, which was driven by slab rollback since 45 Ma, is described here for the first time in two stages. From Middle Eocene to Middle Miocene, deformation was localized leading to i) the exhumation of high-pressure metamorphic rocks to crustal depths, ii) the exhumation of high-temperature metamorphic rocks in core compl...

The Lesser Antilles subduction initiated in Lower Cretaceous at the eastern tip of the Caribbean plate where Atlantic is subducting westward bellow Caribbean plate. The associated island arc extends from St Martin (to the north) to Grenada Island (to the south). The northern half of the volcanic arc presents a peculiar morphology with (i) an easter...

Aegean extension is a process driven by slab rollback that since 45 Ma shows a two-stage evolution. From 45 to 13 Ma it is accommodated by localized deformation leading to i) the exhumation of high-pressure metamorphic rocks from mantle to crustal depths, ii) the exhumation of high-temperature rocks in core complexes and iii) the deposition of Pale...

Oblique extension is expected to result in a combination of dip-slip and strike-slip displacement along faults with strike orthogonal and oblique to the extension direction, respectively. This general con- cept is in disagreement with observations from natural oblique rifts, where faults show dip-slip kinematics indicating pure extension irre- spec...

Oblique extension is expected to result in a combination of dip-slip and strike-slip displacement along faults with strike orthogonal and oblique to the extension direction, respectively. This general con- cept is in disagreement with observations from natural oblique rifts, where faults show dip-slip kinematics indicating pure extension irre- spec...

The Aegean domain is a key area for understanding the processes of back-arc extension. Observed deformation pattern and present day kinematics result from the interaction between the southward retreat of the Hellenic trench and the westward escape of Anatolia. Lithosphere-scale analogue models were employed to display that the overall pattern of Ae...

The interaction between Aegean back-arc extension and Anatolia escape since Middle Miocene. Abstract. The Aegean domain is a key area for understanding the processes of back-arc extension. Observed deformation pattern and present day kinematics result from the interaction between the southward retreat of the Hellenic trench and the westward escape...

The Aegean domain is a key area for understanding the processes of back-arc extension. Observed deformation pattern and present day kinematics result from the interaction between the southward retreat of the Hellenic trench and the westward escape of Anatolia. Lithosphere-scale analogue models were employed to display that the overall pattern of Ae...

[1] Southern Ethiopia is a key region to understand the evolution of the East African Rift System, since it is the area of interaction between the Main Ethiopian Rift (MER) and the Kenya rift. However, geological data constraining rift evolution in this remote area still relatively sparse. In this study the timing, distribution and style of rifting...

Oblique subduction produces slip partitioning or decoupling, in which underthrusting of the subducting slab accommodates the margin-normal component of slip while a trench-parallel strike-slip fault accommodates margin-parallel slip. This process triggers the individualization of slivers of lithosphere between the trench slope and the large-scale s...

We present an analysis of the distribution, timing and characteristics of the volcano-tectonic activity on the western margin of the Southern Main Ethiopian Rift in the Soddo area (latitudes between 7°10’N and 6°30’N). The margin is characterized by the presence of numerous normal faults, with limited vertical offset and often sigmoidal in shape,...

Lawsonite pseudomorphs are used to identify and distinguish the kinematic records of subduction and exhumation in blueschist-facies rocks from Syros (Cyclades; Greece). Lawsonite is a hydrous mineral that crystallizes at high-pressure and low-temperature conditions. During decompression, lawsonite is typically pseudomorphed by an aggregate dominate...

In this study, we draw on a unique combination of well-resolved fault-slip data and earthquake focal mechanisms to constrain spatial variations in style of faulting in the obliquely extending Main Ethiopian Rift, East Africa. These data show that both boundary and internal faults – oblique and orthogonal to the plate divergence (PD) respectively –...

Understanding how heterogeneities within the lithosphere influence the deformation pattern in continental rifts still remains a challenge and is of real importance to constrain continental break-up. We have selected the Main Ethiopian Rift in East Africa and the Rio Grande Rift in the south-western U.S. These two rifts are perfect natural laborator...

The geometry of continental rifts is strongly controlled by the rheology of the lithosphere at the onset of rifting. This initial geometry will further control the development of ocean spreading centers and the structure of adjacent passive margins. Therefore, understanding the influence of coupling between the different layers of the lithosphere w...

The Main Ethiopian Rift (MER) is the oblique NE-SW trending plate boundary between Nubia and Somalia that developed above an inherited lithospheric-scale weak zone, the Mozambique Ocean Suture Zone (MOSZ). In this area, plate’s kinematics has been estimated from various sources including: GPS and seismic data, spreading rate estimates, magnetic ano...

Understanding how initial heterogeneities and boundary conditions control the development of fault network and the deformation partitioning mechanisms in rifts that affects continental crust still remain a challenge. Among the active continental rift affecting the Earth lithosphere, the Main Ethiopian Rift (MER) & the Rio Grande Rift (RGR) appear t...

The Main Ethiopian Rift (MER) is the NE-SW trending plate boundary between the Nubian and Somalian plates. Whereas the Northern MER displays a N50-55° trend, the Central MER itself displays a N30-40° trend, this peculiar shape is classically attributed to the presence of an inherited lithospheric-scale weak zone, above which the MER initiated and d...

We review the geodynamic evolution of the Aegean–Anatolia region and discuss strain localisation there over geological times. From Late Eocene to Present, crustal deformation in the Aegean backarc has localised progressively during slab retreat. Extension started with the formation of the Rhodope Metamorphic Core Complex (Eocene) and migrated to th...

The Main Ethiopian Rift (MER) in East Africa is considered the ideal place to analyze the process of continental rifting since along its length it records all the different stages of rifting. Indeed, whereas the southern parts of the rift are believed to record the early stages of extension, with deformation localized at large boundary faults, the...

Oblique rifting in the central and northern Main Ethiopian Rift (MER) has resulted in a complex structural pattern characterized by two differently oriented fault systems: a set of NE-SW-trending boundary faults and a system of roughly NNE-SSW-oriented fault swarms affecting the rift floor (Wonji faults). Boundary faults formed oblique to the regio...

High pressure metamorphic rocks exposed in the core of many mountain belts correspond to various types of upper crustal materials that have been buried to mantle depths and, soon after, brought back to surface at mean displacement rates up to few cm/y, comparable to those of plate boundaries. The vertical component of HP rock exhumation velocity ba...

The Cycladic Blueschist Unit (CBU) represents the northern passive margin of the Adria continental block and ophiolites that are the remnants of the Pindos Ocean, which were affected by high pressure–low temperature metamorphism in the blueschist and eclogite facies during the Eocene. Prior to the Lutetian, the ophiolitic and margin units were thru...

1] On Syros, high‐pressure metamorphism affects a lithological pile that is composed of, from base to top: (1) the Komito‐Vari granitic basement, (2) a margin sedimentary sequence that is predominantly made of marbles and schists (the Pyrgos and Kastri units), and (3) the Kambos metaophiolitic mélange. The tectonic history occurred in three main st...

Subduction zones allow important vertical movement across the lithosphere and the upper mantle. High-Pressure/Low-Temperature (HP/LT) metamorphic rocks represent part of the material first buried and then exhumed during subduction. In the Cyclades (Greece), HP units have surprisingly conserved (1) their initial geometry and even their stratigraphy...

Deciphering between deformations related to subduction and exhumation in HP metamorphic rocks represents a challenge for the understanding of the dynamic processes involved and more particularly, the exhumation mechanisms. An analysis of shear criteria in the Ile de Groix blueschists in the Hercynian Belt of southern Brittany (Western France) is ca...