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Landslides and rockfalls are a common hazard in mountain areas like the Pyrenees. However, due to the difficulty of access and therefore of data acquisition, and the low density of population they are poorly studied. The Tartera de Cambrils, is located in a small town in the Solsonès region, Catalonia, and is the product of ancient landslides and succeeding rockfalls. These processes can endanger different infrastructures in the village of Cambrils such as the road, the sports centre, the salt flats called 'El Salí' (currently also being used for tourist activity), two inns and several houses. This study aims to determine the processes that caused the initial landslides, those that occur at the rock slope nowadays and their causative factors. For this, we compiled information from the literature, conducted a field study building a geologic and geomorphologic cartography and acquired LiDAR data, with a Terrestrial Laser Scan, and photographs in order to produce three-dimensional point clouds. We also analyse the rock-cliff stability using photogrammetry and LiDAR data and direct measures of rock mass discontinuities. The bedding dips smoothly and contrary to the slope, making planar sliding an unprovable mechanism, favouring wedge sliding and toppling. The rock discontinuities are the main causative factor of rockfalls. Rockfall originates from rock fronts of decametric volume along the main scarp and on the scree. These rock fronts rotated respect to the rock in situ. The farther away from the main scarp, the larger the rotation of the blocks. The analysis of the fractures allows estimating an important possibility of rockfall directly affecting the inns and the road and provides fundamental data for the development of protection measures.

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - Gasteiz, La conexión plutónico-volcánica se ha postulado principalmente en base a enfoques petrológicos, geoquímicos, geocronológicos, y geofísicos, y modelos teóricos, todos ellos proporcionando evidencia indirecta, aunque de momento se han ofrecido muy pocos ejemplos de campo de dicha conexión. La razón es que la mayoría de los terrenos volcánicos bien expuestos son demasiado jóvenes para que la erosión o la tectónica hayan exhumado sus raíces plutónicas más profundas, mientras que los terrenos plutónicos son demasiado viejos para preservar los posibles equivalentes volcánicos. El volcanismo del Pérmico Superior-Carbonífero-Inferior del Pirineo catalán ofrece una excepción a esta regla general, y expone varias rocas plutónicas, subvolcánicas y volcánicas contemporáneas y cogenéticas, ofreciendo así un buen ejemplo de campo de la existencia de dicha conexión plutónico-volcánica. La reconstrucción estratigráfica y estructural basada de este complejo plutónico-subvolcánico-volcánico, así como las nuevas edades radiométricas U-Th en circones, demuestran que hubo una relación tiempo-espacio entre todos ellos, ofreciendo así uno de las pocas evidencias directas de la existencia de la conexión plutónico-volcánica. Esta contribución es parte del proyecto SIMPRROP-CGL2017-84901-C2, The volcanic-plutonic connection has been postulated mostly based on petrological, geochemical, geochronological, and geophysical approaches, and theoretical modelling, all them providing indirect evidence, but for now very few direct field examples of such connection have been offered. The reason is that most well-exposed volcanic terrains are so young for erosion or tectonics to have exhumed their deeper plutonic roots, while plutonic terrains are too old to preserve possible coeval volcanic equivalents. The Upper Carboniferous-Lower Permian volcanism of the Catalan Pyrenees offers an exception to this general rule, and exposes several co-genetic and coeval plutonic, subvolcanic and volcanic rocks that offer good field evidence of the existence of such volcanic-plutonic connection. The field-based strati- graphic and structural reconstruction of some of these plutonic-subvolcanic-volcanic complexes, as well as new zircon U-Th radiometric ages, demonstrate that there was a time-space relationship between all them, thus offering one of the scarce direct evidence of the existence of the volcanic-plutonic connection., This contribution is part of the Spanish grant SIMPROP-CGL2017-84901-C2

Bathurst Meeting of Carbonate Sedimentologists 2019, Diagenesis of platform carbonates juxtaposed to diapiric structures is complex due to the interaction between host rock and fluids related to, and not related, to diapirism. The exposure of low structural levels and excellent outcrop conditions of the Tazoult salt wall allows the analysis of the diagenesis of the Hettangian to Pliensbachian platform carbonates flanking the structure. It was possible to interpret the diagenetic evolution occurring in the studied rocks from the early stages of the diapiric activity through to the Alpine tectonic inversion of the entire rift basin. Field and analytical data revealed the occurrence of several diagenetic phases (eight types of calcite cements and five types of dolomites) affecting the host rock. These characterise seven diagenetic stages linked to the halokinetic evolution of the Tazoult salt wall. Stage 1 (early Pliensbachian) to stage 4 (late Pliensbachian) occurred during the early growth of the Tazoult salt wall, and they were characterised by the alternation of marine and meteoric diagenetic environments. Stage 2 is of special interest as the Tazoult wall underwent an increase in diapiric activity that promoted the uplift and the subaerial exposure of the platform carbonates. The invasion of the platform top by meteoric waters caused the karstification of the host limestones and the deposition of karstic sediments. Stage 5 (Toarcian) represents the early burial of the studied units and was distinguished by the circulation of marine dolomitizing fluids downward along the contact between the diapir core and the flanks. Stage 6 (post-Toarcian) represented the maximum burial of the studied platform carbonates. During this stage, the contact between the diapir core and the flanking sediments acted as a barrier to the circulation of fluids. Stage 7 (Cenozoic) corresponds to the uplift and exhumation event related to the Alpine compression, when all the studied carbonates were exposed and subsequently interacted with meteoric waters. Based on analytical data the estimated temperatures of diagenetic fluids were obtained and compared to thermal and burial history of the studied basin. This multidisciplinary integration allows us to present a large-scale discussion of the timing of diagenetic events and thermal sources, not only for the Tazoult salt wall area but also in other localities with similar geological histories. Results suggests that the Tazoult salt wall constitutes a first class example of how salt tectonics influences the diagenetic evolution of sediments flanking diapiric structures. Major controls on diagenesis are: i) the creation of fluid pathways, mostly fractures, due to the forces caused by the upward migration of salt during early stages of diapirism; ii) the local sea-level variation due to relative vertical salt movement that causes alternation of marine and meteoric diagenetic processes, which is especially relevant in platform carbonates; iii) the behaviour of diapirs and welds as preferential vertical fluid conduits, but as barriers to the horizontal migration of fluids; this is therefore partially or totally compartmentalising minibasins; and iv) the influence of salt and other evaporite dissolution from diapirs on the fluid chemistry and related diagenetic products and ore deposits.

Alpine Folded Belts and Extensional Basins (GRW events) , 15-16 march, 2018, Granada, Spain, The Central High Atlas of Morocco is a Jurassic salt-related rift basin inverted during the Alpine orogeny characterized by an intricate polygonal network of salt walls separating minibasins. Field data on both structural geology and sedimentology of halokinetic sequences, thermal modelling and subsidence analysis, analogue modelling, diagenetic studies as well as balanced and restored cross-sections on Jurassic-aged diapiric structures and minibasins provide an integrated interpretation of Central High Atlas as well as multiple examples of the impact of syn- and post-rift diapiric activity on the evolution of the Jurassic basin of the Central High Atlas at different scales.

Analogue modelling has proven to be an essential tool for the study and analysis of the mechanisms involved in tectonic processes. Applied to salt tectonics, analogue modelling has been used to understand the mechanisms that trigger the onset of diapirs and the evolution of diapiric structures and minibasins. Analogue modelling has also been applied to analyse the impact of the progradation of sedimentary systems above a ductile layer, representing the source of diapirs. However, these models did not consider ongoing tectonic processes during progradation. To analyse how extension and sedimentary progradation influence on the formation of diapiric structures and their geometries, we present models composed of a mildly extension followed by post-extension period. Each model includes a particular sedimentary pattern: homogeneous sedimentation during extension and post-extension, homogeneous sedimentation during extension followed by prograding sedimentation during post-extension and prograding sedimentation during both extension and post-extension. Proximal high sedimentation rates enhance the mobilization of ductile material towards growing diapirs, resulting well-developed passive diapirs. Diapirs from distal domain of the model with post-extension progradation show silicone extrusions, that are caused by the decreased sedimentation rate associated to the progradation. By contrast, reduced sedimentation in the distal part of the model with syn- and post-extension progradation (3.5 times smaller than in the proximal domain) causes a limited migration of the silicone and hampers the transition from reactive diapirs to active and passive diapirs. These models show that the ratio between diapir growth and sedimentation rate, the time of the onset of the progradation and the relative thickness of the sedimentary cover beneath the prograding system have a clear impact on the final diapiric geometries. Additionally, we present two models with increasing amounts of shortening (6% and 10%). These models show that the presence and location of diapirs clearly controls the distribution of the deformation associated with the inversion, primarily affecting the post-diapiric layers in the vicinities of the salt structures whereas very little deformation occurs away from diapirs. This deformation pattern is observed in the Early to Middle Jurassic Tazoult salt wall and Azourki diapir of the Central High Atlas (Morocco). These structures show that the deformation associated with the Alpine orogeny is focused on the sedimentary units fossilizing the salt structures and mainly localised above them. The presented results provide key information that can be applied to other diapiric structures of the Central High Atlas diapiric basin and similar examples elsewhere., This study was part of a collaborative research project funded by Statoil Research Centre, Bergen (Norway). Additional funding by the CSIC-FSE 2007-2013 JAE-Doc postdoctoral research contract (E.S.), the projects Intramural Especial (CSIC 201330E030) and MITE (CGL 2014-59516). and by the Grup Consolidat de Recerca >Geologia Sedimentària> de la Generalitat de Catalunya (2014GSR251). We are grateful to Statoil for its support and permission to publish this study.

During Mesozoic time, the extensional basin of the Central High Atlas in Morocco underwent two consecutive rifting events: Permo-Triassic and Early-Middle Jurassic in age. However, a review of the literature reveals that the precise timing of the Early-Middle Jurassic rift and post-rift transition varies depending of the analysed area. The discrepancy about rifting ages is associated with the general lack of normal faulting cutting post-Lower Jurassic strata and the presence of significant salt diapiric activity during Early and Middle Jurassic in the central part of the basin. To evaluate the influence on subsidence patterns of the interaction between both extensional and salt tectonics, we present new subsidence data from diverse paleogeographic and tectonic settings of the Central High Atlas rift basin. From the periphery of the basin, the Djebel Bou Dahar platform-basin system corresponds to a shallow carbonate platform developed on top of a basement high, controlled and bounded by normal faults. The results of the subsidence analysis show long-term and low-rate of tectonic and total subsidence (0.06 and 0.08 mmyr-1 respectively). The roughly parallel evolution of both total and tectonic subsidence curves indicates the tectonic influence of the platform-basin system, as corroborated by the syndepositional fault activity of the outcropping Sinemurian-Pliensbachian normal faults. Contrarily, the rift axis is characterised by the presence of diapiric salt ridges and minibasins as in the Tazoult-Amezraï area and Imilchil diapiric province. Comparison between subsidence curves from the SE flank of the Tazoult salt wall and from Amezraï minibasin centre shows that, from Pliensbachian to Aalenian, the tectonic and total subsidence rates of the Amezraï minibasin (between 0.17-0.32 mmyr-1 and 0.38-0.98 mmyr-1) are two-fold their equivalent rates in the Tazoult salt wall. Amezraï minibasin values are in agreement with the values from Imilchil minibasins (tectonic and total subsidence up to 0.23 and 0.90 mmyr-1). Additionally, Imilchil minibasins record the migration of maximum subsidence rate through time. Thus, the rift axis show subsidence rates one order of magnitude higher than rates from basin periphery, spatial and temporal migration of subsidence rate maxima and anomalous high subsidence amounts during post-rift phase. These characteristics point to a combination of normal fault extension and salt withdrawal from beneath the minibasin during the rifting, being the salt-related subsidence predominant during the post-rift and masking the expected subsidence pattern of a rift-post rift transition. The comparison between the new subsidence curves from the Central High Atlas with other published works from the Atlas Tethyan domain reveals similar subsidence patterns and the close relationship between high subsidence rate episodes and salt diapirism in the entire Atlas system., This study was part of a collaborative research project funded by Statoil Research Centre, Bergen (Norway). Additional funding by the CSIC-FSE 2007-2013 JAE-Doc postdoctoral research contract (E.S.), the projects Intramural Especial (CSIC 201330E030) and MITE (CGL 2014-59516). We are grateful to Statoil for its support and permission to publish this study.

AAPG 2017 Annual Convention & Exhibition, 2-5 April 2017, Houston, Texas, United States, Hydrocarbon exploration in diapiric provinces has proved to be challenging. In this type of settings, vertical beds, steep and complex salt walls and subsalt domains make seismic imaging a complex exercise. Moreover, the dynamic interaction between salt diapirism and deposition produces complex 3D reservoir geometry and distribution. In this work, we present data from superbly exposed outcrop analogues from La Popa Basin in Sierra Madre Oriental (Mexico), the Central High Atlas diapiric province (Morocco), the Ribagorça Basin in the Southern Pyrenees and the Maestrat Basin in the Iberian Range (Spain). The studied areas provide examples of salt diapirs, salt welds, salt rollers, halokinetic strata, minibasins of different dimensions, megaflaps, allochthonous salt sheets, salt overhangs and rafts. The study, based on a multidisciplinary approach that combines field mapping, remote sensing, structural, sedimentological and diagenetic analysis of the halokinetic sequences, improves the understanding of the geometries, extension, composition and facies distribution of the syndiapiric sediments, with special focus on the distribution of carbonate facies. Of particular interest are spectacular subsalt domains exposed in all the studied basins, where subvertical halokinetic hooks and wedge stacks consistently show facies deepening away from the diapir. Shallow water carbonates, reef patches, coral build ups, slope breccia and oolitic shoals are not rare in these domains. The results of this work might be used to improve seismic processing, the interpretation of borehole data, and the evaluation of business opportunity in similar settings.

AAPG Annual Convention and Exhibition 2¿5 April, 2017, in Houston, Texas, USA., The fabulously cropping out Central High Atlas in Morocco is defined as a major diapiric province during Jurassic times. An intricate polygonal network of salt walls separating minibasins with different orientations characterized the Atlas Rift Basin. Field data on both structural geology and sedimentology of halokinetic sequences, significant remote sensing mapping using good quality satellite images, thermal modelling and subsidence analysis, balanced and restored cross-sections and analogue modelling allowed us to construct an integrated tectonosedimentary interpretation of Central High Atlas salt-related rift basin. The analysis of three areas (Tazoult, Jbel Azourki and Imilchil) reveals a consistent evolution of this diapiric domain. Analysed diapiric ridges (salt walls) show a similar evolution with the main distinctions related to both regional main geodynamic changes in the Jurassic Rift Basin and local different ratios of diapir rise and sediment accumulation. The Tazoult and Jbel Azourki salt wall developed by post- Hettangian extension triggering reactive-active diapirism after 199 Ma followed by a long period of passive diapiric growth roughly from 199 Ma to before 170 Ma. Its partial fossilization at about 168 Ma took place during Middle Jurassic although some close localities show halokinetic sequences of this age. The diapiric activity in Imilchil is recorded at least since the Toarcian (Early Jurassic at around 183 Ma) up to the Callovian (Middle Jurassic at around 164 Ma). At the larger scale, the diachronic evolution between extension and diapirism along the Atlas suggests that diapirism and salt withdrawal play an important role not only in the Central High Atlas in Morocco but also along the Saharan Atlas in Algeria and Tunisian Atlas.

The central High Atlas (Morocco) constitutes a diapiric province that hosts a complex array of elongated diapirs and minibasins that formed during the Lower Jurassic rift of the Atlas Basin. This paper aims to study the structure and growth evolution of the Tazoult diapiric wall, located in the central High Atlas, by means of structural and sedimentological fieldwork integrated with remote sensing mapping. The Tazoult salt wall is a 20km long×3km wide NE-SW trending ridge that exposes Upper Triassic red beds and basalts along its core. The succession flanking the salt wall ranges from Hettangian to Bajocian ages displaying spectacular sedimentary wedges in the SE and NW flanks. The Hettangian-early Sinemurian carbonates mainly crop out as blocks embedded in the core rocks. The ~1km thick Pliensbachian platform carbonates display large subvertical flap structures along the flanks of the Tazoult salt wall with unconformities bounding tapered composite halokinetic sequences. In contrast, the ~2.5km thick late Pliensbachian-Aalenian mixed deposits form tabular composite halokinetic sequences displaying small-scale hook halokinetic sequences. Passive diapirism resulted in the lateral extrusion of the evaporite-bearing rocks to form an allochthonous salt sheet toward the adjacent SE Amezraï minibasin. The Bajocian platform carbonates partially fossilized the Tazoult salt wall and thus constitute a key horizon to constrain the timing of diapir growth and discriminate diapirism from Alpine shortening. The Pliensbachian carbonate platform evolved as a long flap structure during the early growth of the Tazoult salt wall, well before the onset of the Alpine shortening. © 2016. American Geophysical Union. All Rights Reserved., Additional funding was provided by the Spanish Ministry of Education and Science (MEC) through the projects Intramural Especial (CSIC 201330E030) and 201530E082), Atiza (CGL2009-1355), Tecla (CGL2011-26670), and the postdoctoral research contract to E.S. (CSIC-FSE 2007-2013 JAE-Doc), as well as by the Generalitat de Catalunya (2014GSR251).

GeoMod 2016 conference Montpellier, France | 17–20 October 2016, Analogue modelling has been previously applied to the analysis of the impact of the progradation of a sedimentary system above a ductile layer (McClay et al., 1998). Commonly, diapiric architecture increases in complexity with: (i) lobe progradation, where the radial shape of the prograding system causes a complex network of polygonal or circular depocenters separated by salt ridges (Gaullier and Vendeville, 2005); (ii) basement topography beneath the ductile layer (Ge et al., 1997); and (iii) the confluence of two sedimentary wedges (Guerra and Underhill, 2012). The outstanding results obtained in all these models, however, did not consider ongoing tectonic processes during diapirism. We present 2 models with two phases (extension and post-extension phases) with different timing of progradation of sedimentary wedge in order to analyse how the time relationship between extension and sedimentary progradation control the formation of diapiric structures and their geometries.

IX Congreso Geológico de España, Huelva, 12-14 de septiembre, 2016, The structure of the Hontomín CO2 geological storage research facility has been addressed combining 3D seismic reflection data, borehole information and microgravity data. The integrated interpretation constrains the basement structural setting geometry and that of the sedimentary succession. The study unravels the deep structure and topography of the basement and quantifies the thickness of the Triassic Keuper evaporites. We describe a half-graben setting filled with Keuper evaporites (up to 2000 m) forming an extensional forced fold. Three set of faults are identified with two main fault systems compartmentalizing the area into three differentiated blocks. These faults have been interpreted to be reactivated normal faults that have led to the formation of the Hontomín dome., Institut de Ciéncies de la Terra Jaume Almera, España, Department of Geology and Petroleum Geology, University of Aberdeen, Reino Unido, Departamento de Geología, Universidad de Salamanca, España, Instituto Geológico y Minero de España, España

9ª Asamblea Hispano Portuguesa de Geodesia y Geofísica: Madrid 28-30 de junio 2016 / Organizado por la Comisión Española de Geodesia y Geofísica ; Secçao Portuguesa das Unios Internacionais Astronomica e Geodésica ; Universidad Complutense de Madrid, Institut de Ciéncies de la Terra Jaume Almera, España, Department of Geology and Petroleum Geology, University of Aberdeen, Reino Unido, Departamento de Geología, Universidad de Salamanca, España, Instituto Geológico y Minero de España, España

Evaporites can play a major role in controlling the architecture of external orogenic belts, both during extensional and subsequent compressional phases. However, salt can also ‘hide’ deformation due to its ability to flow and dissolve. The challenge is to recognise the imprint of its past presence and influence. In the NE Pyrenees multiple deformation phases have been identified based on locally anomalous stratigraphic and structural relationships. This has resulted in complex, sometimes incoherent and often conflictual models of orogenic history. For example, a pre-Cenomanian deformation phase has been interpreted as either extensional or compressional. As part of the ANR-PYRAMID project, we have re-examined key localities around the eastern Mouthoumet massif, in the Corbières foreland and along the Corbières thrust front to reconstruct a coherent deformation history involving salt tectonics. Keuper (Carnian – Rhetian) evaporitic deposits gave rise to diapirs and detachments that were particularly active during Early to Late Cretaceous extension and later during Late Cretaceous to Eocene compression. Growth unconformities and rapid thickness changes in the Aptian Quillan basin indicate that it developed as a salt controlled minibasin. Olistoliths, gypsum breccias and presence of bipyramidal quartz in Albian strata preserved as footwall imbricates along the North Pyrenean thrust front (e.g. around Cucugnan) attest to the proximity of a large diapiric body. Below the Cenomanian unconformity, rotated fault blocks of Liassic to Albian strata lie above a Keuper detachment. These extensional fault blocks have already been recognised at the Serre de Bouchard. They are also preserved north of Cucugnan, in the Montagne de Tauch and in the Fontfroide massif with little or no alpine inversion. In the Corbières foreland area salt-influenced extensional and compressional deformation generated growth folds, with completely overturned limbs (flaps), welds, growth unconformities and pinched salt-cored anticlines. Several of these structures have generated considerable controversy in the past (Pinède de Durban, Boutenac anticline, Ripaud syncline). In the light of new advances in understanding salt-related stratal and fault geometries we propose a new interpretation of these foreland structures integrating halokinesis, which leads to a new coherent regional tectonic history.

The halokinetic structure of inverted salt-related continental margins is frequently obliterated by compressional overprinting. The Cretaceous Sopeira and Sant Gervàs subbasins of the Ribagorça Basin (south central Pyrenees) show evidence of salt-related extensional tectonics and diapiric growth along the Iberian Margin of the Mesozoic Pyrenean rift. We present an integrated field-based tectonic-sedimentary study to reconstruct the evolution of the Ribagorça Basin system previous to, and in the early stages of, the Pyrenean orogeny. The ~4km thick Albian-Cenomanian Sopeira minibasin infill thins toward the basin borders, especially toward the eastern, N-S trending, Llastarri salt weld. The 90° tilt to the south of the Sopeira basin bottom records the growth of the buried north dipping Sopeira listric fault from Albian to Santonian times, when it evolved as an extensional rollover associated with the Aulet salt roller. The ~3km thick Cenomanian-Campanian succession filling the Sant Gervàs flap displays 130° bed fanning attitude from overturned Cenomanian carbonate platform strata to upright Campanian turbidite beds. The Sant Gervàs flap development since Cenomanian times was related to the fall of a large salt pillow after the main Soperia minibasin stage. Jurassic-Campanian diachronous subsidence is also observed in the adjacent Montiberri, Faiada, and Tamurcia depocenters. Correlation with the Pedraforca, Cotiella, and Basque-Cantabrian Basins along the southern Pyrenees suggests that a significant segment of the Iberian side of the Pyrenean rift experienced a gravity-driven extension from Albian to late Santonian. The Ribagorça Basin provides an excellent field analogue for presently buried salt-related structures of extended passive margins., This research was carried out with the aid of grants by CSIC-ESF 2007–2013 JAE-Doc postdoctoral research contract (E.S.) and with funding from the Spanish Research Agency through projects CGL2009-1355, CGL2011-26670, and CGL2010-15416. Additional funding was provided by Atlas Project and Statoil Research Center

Hontomín (N Spain) hosts the first Spanish CO2 storage research plant. The geophysical characterisation of the site included the acquisition of a 36 km2 3D seismic and a 16 km2 3D microgravimetric datasets. The integration of these data is here used to: (1) reproduce the deep structure and topography of the basement; (2) quantify the thickness of the Triassic Keuper evaporites, located between the sedimentary succession and the metamorphic basement; and (3) establish relationships between the faults interpreted in the seismic data and those inferred from the gravimetric data in the basement. The geometry of the sedimentary succession and structures interpreted from the seismic volume were used to constrain the inversion of the microgravity data: i.e. their gravimetric signature was calculated and then removed from the Bouguer Anomaly, thus reducing the uncertainty in the inversion process. The derived top of the basement geometry was used, along that of the top of the Triassic Keuper, to calculate the salt thickness., Research supports: CGL2014-56548-P, 2009-SGR-1595, VATC: 20133830

A multidisciplinary study has been carried out in Hontomín (Spain) to determine the basement structural setting, its geometry and the geometry of the sedimentary succession of an area aimed to be the first Spanish pilot plant for CO2 storage. An integration of coincident 3-D seismic results, borehole data and unpublished microgravity data were used to reproduce the deep structure and topography of the basement and to quantify the thickness of the Triassic Keuper evaporites. The subsurface structure is characterized by a half-graben setting filled with Keuper evaporites (up to 2000m thick), forming an extensional forced fold. All data sets clearly identify two main fault systems, compartmentalizing the main structural domain into three differentiated blocks. These faults have been interpreted to be reactivated normal faults that have led to the formation of the Hontomín dome. © Author(s) 2016., The data sets in this work have been funded by Fundación Ciudad de la Energía (Spanish Government, www.ciuden.es) and by the European Union through the “European Energy Programme for Recovery” and the Compostilla OXYCFB300 project. Juan Alcalde is currently funded by NERC grant NE/M007251/1.

Carbonate platform development and demise can be closely related to subsidence history, clastic sediment supply and rates of carbonate growth/deposition, among other factors. Due to the impact of rapid salt movements, patterns of carbonate platform development and deposition are generally more complicated on diapiric passive margins, as are widely developed in the Gulf of Mexico and along the North- and South-Atlantic margins. Field analogue studies are a key tool in order to increase the understanding of the carbonate depositional systems developed in diapiric settings. We have carried out integrated structural, subsidence history, sedimentological and diagenetic studies on Jurassic-aged diapiric structures superbly-exposed in the Central High Atlas, Morocco. Detailed study has been carried out on ten elongate diapiric ridges (i.e. up to 30 x 2 km) and eight minibasins, that encompass a range of proximal and distal settings. The elongate diapirs that control the Jbel Azourki, Tazoult, Tassent, Ikkou and Toumliline ridges, and associated minibasins. These provide multiple examples of halokinetic geometries including bed thinning, onlaps and truncations that comprise composite stacks of halokinetic wedges and hook sequences. The influence of diapir growth on the carbonate deposition is linked to rapid lateral facies changes and shallow bathymetries developed over the diapirs, as well as the rotation, karsitification and erosion of the carbonates platforms in proximity to the diapirs. Together with diapirism, increased siliciclastic supply is linked to both the demise and changes in the location of carbonate platform development on the diapirs. As such, the Central High Atlas provide valuable insights as to the intricate relationships between carbonate production, salt tectonics, clastic sediment input, and paleowater depth that be applied to the subsurface., This study is funded by Statiol Research Centre, Bergen (Norway), by the Spanish Ministry of Education and Science (MEC) throght the projects Intramural Especial (CSIC 201330E030) Atiza (CGL2009-1355) and Tecla (CGL2011-26670), as well as by the CSIC -FSE 2007-2013 JAE Doc Postdoctoral research contract (E.S.) We are grateful to Statiol for its support and permission to publish this research.

©2015. American Geophysical Union. All Rights Reserved. The evolution of the Amiran and Mesopotamian flexural basins of the Zagros belt is approached by coupled 2-D forward modeling of orogenic wedge formation, lithospheric flexural isostasy, and stream power erosion/transport/sedimentation. Thrust geometries and sequence of emplacement derived from geometric and kinematic models presented here are the inputs to our evolutionary model, constrained by basin geometry, sediment volume, and topography. Modeling results confirm that the Zagros flexural basins evolution is consistent with two stages of deformation: (1) the obduction stage involving the Kermanshah accretionary complex and a basement unit and (2) the collision stage, emplacing the Gaveh Rud and Sanandaj-Sirjan domains in the hinterland and forming a basement duplex in the outer part. Results provide quantitative insights into processes involved in mountain and basin building. The lithospheric equivalent elastic thickness (Te) changed from 20 km during the Amiran stage (~90-50 Ma) to 55 km during the Mesopotamian subsidence stage (last 20 Myr). The Amiran basin results from flexure of the Arabian plate below the load of the Kermanshah cover and basement thrust sheets. During this stage, material eroded in the inner parts was enough to fill the flexural trough. The Mesopotamian basin formed in front of the outermost basement units flexing the Arabian plate. During this latter stage, material eroded from the orogenic wedge was not enough to fill the Mesopotamian basin. An additional longitudinal sediment supply of up to 200 m/Myr is required to fill the flexural basin., This research was carried out with the aid of grants by CSIC-FSE 2007–2013 JAE-Doc postdoctoral research contract (E.S.) and with funding from the Spanish Research Agency through project Tecla (CGL2011-26670).

19th International Sedimentological Congress, 18-22 August, Geneva, Switzerland, International Association of Sedimentologist, The Jurassic Atlas intracontinental basin in the Central High-Atlas is characterized by a succession of ENEWSW narrow anticlinal ridges and wide synclines, developed by the diapirism of Triassic sediments and later magmatic intrusion along major synsedimentary faults. The core of the diapiric ridges is made of Triassic red shales, magmatic rocks and some evaporites. These diapiric structures are particularly well preserved in the Imilchil region, an ideal area to study the interaction between sedimentation and diapirism. The objective of this study is to place local diapiric movements and associated deformation and facies changes within the context of regional subsidence and facies patterns. The effects of diapir movements on sedimentation are demonstrated by intra-formational geometries (thickness variations, unconformities), facies variations close to the diapirs (local influence on the depositional profiles), and/or by specific events (erosional surfaces, breccia, condensed levels). Toarcian to Bathonian halokinetic sequences define two main phases of diapiric activity. The first major phase of diapiric movements occurred during the Toarcian/Aalenian, and is characterized by the presence of progressive unconformities within relatively deep marls and carbonate deposits. In the regional context, this diapiric activity is concurrent with a period of normal faulting. In contrast, reduced diapirism during the Bajocian is recorded by the progradation of oolitic and bio-constructed carbonate platform systems. The second phase of major diapiric activity occurred from the end of the Bajocian to the Bathonian, in relation with a new phase of deformation in the Atlas Basin, associated with magmatic intrusions and tectonic movements. The latter are thought to be responsible for an increase of clastic influx. Carbonate platforms were subsequently replaced by relatively shallow mixed carbonate-siliciclastic and ultimately continental systems, themselves affected by significant synsedimentary diapiric activity and associated deformation. At this stage, the diapirs tended to emerge, and disconnect the mini-basins. The high subsidence rate in these mini-basins allowed the accumulation of 2000 to 3000 meters of sediments during the Bathonian.

AAPG 2014 Annual Convention & Exhibition on 6-9 April 2014, Houston, Texas, United States, Carbonate platforms developed on a diapiric substrate form important passive margin hydrocarbon reservoirs. Much of our present understanding of these systems comes from subsurface data. In an effort to gain new insights of these carbonate and mixed carbonate-clastic systems we have undertaken an integrated structural and sedimentological study of Lower to Middle Jurassic carbonate platform and basin deposition across c. 6000 km2 of the Moroccan High Atlas. This scale of observation is similar in area to a large offshore seismic dataset, and provides a natural laboratory where new understanding of syn- to post-rift diapiric carbonate platforms can be gained. The Atlas intracontinental basin initiated during the Triassic, contemporaneously with Atlantic rifting. A thick continental sequence, dominated by sandstone, shales and evaporites accumulated in multiple tectonic sub-basins. The first regionally extensive Sinemurian carbonate platform developed during thermal subsidence. During the Early Pliensbachian, renewed normal and strike-slip faulting and deformation occurred. The deformation triggered the diapirism of Triassic shales and evaporites. The diapirism impacted on the dynamics and geometries of Pliensbachian carbonate platform systems, and Toarcian-Aalenian mixed siliciclastic/carbonate systems. The ensuing Late Aalenian ¿ Bajocian period was a relatively stable tectonic phase, so that a second extensive carbonate platform developed across the whole Atlas Basin. Diapirism was limited during these times. There was renewed diapirism from the latest Bajocian until the Late Jurassic. This occurred in relation to a new phase of deformation and magmatic intrusions along the crustal faults that also control the location of diapiric ridges. The synsedimentary diapirism had a major influence on the location and geometry of the marine-carbonate and later continental-siliciclastic sequences, that characterize this final stage of the intracontinental basin. Our outcrop studies reveal a close relationship between diapirism and sedimentation, with significantly different responses depending on the type of sedimentary system: carbonate, siliciclastic or mixed. The scale of our work allows us to place locally detailed observations of carbonate platform systems within a regional framework developed at the scale of large 3D seismic surveys. As such, the results of this study are of direct applicability of offshore exploration efforts.

AAPG 2014 Annual Convention & Exhibition, on 6-9 April 2014, Houston, Texas, United States, The impact of diapirism on carbonate, mixed carbonate-clastic and clastic syn-post rift sedimentation is well expressed in Jurassic strata of the Moroccan Central High Atlas. Here elongate diapiric structures delimit platform margins and minibasins. In platform margin settings abrupt platform-basin transitions are delimited and punctuated by en-echelon diapiric structures can be traced over 40 km above buried normal fault systems. These diapirs are limited on one margin by relatively rigid platform carbonates. In contrast in more basinal settings the diapirs pierce more ductile basinal successions and are normally associated with classic diapiric structures. The ENE-WSW trending, 2000-km long Atlas Mountains, extending from Morocco to Tunisia, are classically regarded as a failed Mesozoic left-lateral transtensive rift arm subject to Alpine inversion, folding and thrusting. Internally, the Central High Atlas is constituted by long and continuous NE-SW and short NW-SE trending ridges forming a polygonal array. Triassic evaporite-bearing shales and associated evaporites crop out in the cores of the ridges that became the main source layer for the diapiric structures. The ridge array confines synclines in which distinctive halokinetic geometries (bed thinning, onlaps, truncations and/or sedimentary facies changes decreasing in paleowater depth towards the axis of the ridges) reveal numerous Early-Middle Jurassic diapiric-related mini-basins. The aim of this presentation is to contrast diapirs abutting and delimiting platform carbonates against those developed in more basinal settings. In addition, this new picture of the Central High Atlas, which we now recognize as an exceptionally well exposed natural laboratory for understanding the interactions between halokinesis, tectonics and sedimentation, depicts an analog for buried large salt-related provinces in both rift basins and continental margins.

In syn- and post-rift settings, carbonate platform development and demise can be closely related to subsidence history and/or clastic sediment supply, a situation that can be modified in basins with associated diapirism. The lower Jurassic of the Central High Atlas exposes classic carbonate platform strata developed on the margins and block shoulders of the rift system, such as the Djbel Bou Dahar platform, with platform and basinal deposits developed along the rift axis. In contrast to the rift margin, the rift axis contains a mobile substrate of Triassic strata that gives rise to numerous elongate diapiric structures that bound mini-basins. Structural analysis reveals that many of the diapiric structures developed over buried normal faults that were active from middle Hettangian to late Pliensbachian times. In this setting we integrate detailed sedimentological and structural work with subsidence analysis between the rift margin and rift axis in order to gain a better understanding of the controls on carbonate platform initiation and demise in a syn-post rift setting with and without active diapirism. For the subsidence analysis we use thermal and 1D burial modelling (GENEX software, BEICIP-FRANLAB), constrained by new vitrinite reflectance data. Stratigraphic thicknesses, paleowater depths and age of different stratigraphic units were selected from 2 basin margin localities and from 2 basinal localities. For comparison, we also calculated subsidence history for the Djel Bou Dahar Platform on the rift shoulder, where there is no diapirism. Results indicate the occurrence of two periods of rapid subsidence. The first has a duration of c. 22 My and extended from Late Triassic to early Pliensbachian, and is attributed to the syn-rift stage. The second period, of c. 15 My is characterized by 2.5 times greater subsidence rate (Pliensbachian-Toarcian boundary to Bajocian-Bathonian limit). A significant increase of siliciclastic supply along the entire rift basin resulted in widespread carbonate platform demise, and is coincident with higher subsidence rates in basinal provinces. This was associated with active diapirism and salt withdrawal beneath the minibasins. The intricate relationships between tectonics, salt withdrawal, clastic sediment input, and paleowater depth have a direct impact on the development of Jurassic carbonate platforms in the Central High Atlas, and provide insights with valuable subsurface application.