The Central High Atlas of Morocco is the result of the Alpine tectonic inversion of an intracontinental Mesozoic basin, the infill of which started with thick Upper Triassic clay and evaporite deposition. This slightly deformed mountain range is characterized by narrow ENE-WSW ridges that expose a Triassic core. These ridges bound unique synclines filled by thick Jurassic successions showing well-preserved halokinetic depositional sequences, interpreted as salt-related minibasins. This paper aims to describe and analyze the evolution of diapiric movements and their interactions with Lower and Middle Jurassic carbonate dominated sedimentation in the Imilchil area, which corresponds to the axial part of the Atlas basin. Four diapiric ridges have been identified in this region: the Tasraft, Tassent, Ikkou, and Amagmag, which expose Triassic shales and are intruded by Triassic and Jurassic magmatic rocks. These ridges delineate three minibasins: Ikassene, Lakes (Lake Plateau), and Tilmi (Ikkou), each 5 to 10 km wide, preserving over 6,000 m of Upper Liassic and Dogger deposits. The Atlas basin is filled with five third-order transgression-regression cycles organized as one regressive megasequence. This long regressive trend is expressed by the succession of three depositional systems: i) a distal to proximal carbonate ramp system from the Toarcian to Late Bajocian; ii) a shallow mixed carbonate-siliciclastic system from the Late Bajocian to Early Bathonian; and iii) a fluvial system from the Bathonian to Early Callovian. Throughout this period, the development of coeval diapiric ridges significantly influenced these sedimentary systems, though the intensity of the diapiric activity varied over time. During the Late Bajocian, ridge growth slowed considerably amid the peak progradation of the carbonate systems. It then increased significantly from the latest Bajocian onward, due to a drastic rise in siliciclastic flux and sedimentation rate in the Atlas basin. The effects of diapirism on sedimentation are observed regionally (several kilometers), as minibasins evolve as depocenters, each exhibiting distinct subsidence rates and sedimentary thicknesses. Despite these local variations, the regional scale paleogeography and the sequential organization of the deposits remained largely unaffected. On a smaller scale (hectometers to kilometers), diapiric structures are always characterized by halokinetic depositional patterns. Internal angular unconformities only occur in very shallow-marine to continental deposits during periods of maximum ridge growth and subaerial exposure (notably in the Bathonian). At this scale, diapiric movements lead to local facies variations within shallow-marine deposits, fostering the development of bioconstructed or grainy carbonate sediment bodies along the ridges. However, in outer ramp environments, the submarine topographies created by ridge growth were generally insufficient to induce similar facies variations.

In the Posušje region of the External Dinarides (Bosnia and Herzegovina), bauxite deposits are hosted along a Late Cretaceous–Paleogene forebulge unconformity that records an extended emersion phase of the Adriatic Carbonate Platform. Historically, open-pit mining has targeted surface and shallow subsurface bauxite bodies, but ongoing exploration must now focus on deeper structurally preserved deposits. To address this challenge, we integrate remote sensing, geological mapping, borehole data, and 3D structural modeling to assess the distribution and structural controls of bauxite deposits. Balanced and restored cross-sections reveal a complex interplay between inverted normal faults, fold structures, and foredeep burial, which collectively influenced bauxite accumulation and preservation. Statistical analyses of deposit size, shape, and orientation indicate that larger bauxite bodies are concentrated in the footwalls of inverted normal faults, where prolonged or repeated exposure enhanced karst development and bauxite accumulation. Additionally, the predominant NW–SE elongation of bauxite bodies suggests that pre-existing structural lineaments played a key role in paleokarst morphology, supporting the influence of syn-depositional extensional faulting on bauxite distribution. These findings demonstrate that bauxite exploration in fold–thrust belts requires an integrated structural approach, where 3D geological modeling can delineate prospective areas prior to costly geophysical surveys and drilling campaigns. Insights from the Posušje region can refine mineral exploration strategies in other orogenic settings, highlighting the importance of structural inheritance in karst bauxite accumulation and preservation.

Continental passive margins are often defined by early salt-related rift systems buried beneath thick sedimentary piles, with structural and sedimentary architectures only directly observable when inverted in orogenic systems where primary salt structures are overprinted by compression. The Central High Atlas diapiric province (Morocco) is an inverted salt-related rift basin with active salt tectonics since early Mesozoic times that provides an exceptional view of early syn-rift sediments and structure. We present the first regional balanced and restored cross-sections of the Central High Atlas evidencing the role of salt tectonics. The cross section includes seven salt walls and six minibasins, with associated Early Jurassic to Cenozoic halokinetic strata that indicates a shortening of 38 km (24%). The Jurassic rifting stage is characterized by shallow water sediments along the basin margins and around localized salt walls, separated by minibasins filled with deep-water sediments undergoing higher subsidence rates. Subsequently, a longitudinal deltaic system prograded eastwards coevally with shallow marine deposition associated with active salt walls. Thus, local diapir uplift enhanced shallow-water deposition and local aerial exposure in central parts of the basin throughout the whole rifting stage. These features provide insights for the study of rift basins and the early stages of continental break-up worldwide, and for the exploration and production of hydrocarbons in equivalent settings.

The interaction of the lithosphere with surface processes in fold-and-thrust belts often leads to the formation of mineral ore deposits, including economically significant resources like bauxites. These interactions are driven by complex geological dynamics, including crustal deformation, sedimentation, and erosion, which create favourable conditions for ore deposition. Bauxite, an essential ore for aluminium production, has become increasingly critical due to global demand and is now included in the European Union's fifth list of critical raw materials. The Dinarides, a branch of the Alpine Belt in south-eastern Europe, are notable for their multiple bauxite levels, making them an important case study for understanding bauxite ore deposits. The External Dinarides are traditionally divided into two tectonic units: the High Karst Unit and the Dalmatian Unit. Historically, these external Dinarides have been interpreted as a thin-skinned fold-and-thrust belt, characterized by significant horizontal shortening and detachment along sedimentary layers.This study proposes a new model for the evolution of the Dinarides, mapping the spatial and temporal distribution of bauxites providing valuable insights into the processes that control their formation, with the ultimate aim to provide broader implications for exploration strategies in similar geological settings.The new model is based on regional balanced and restored cross-section through the External Dinarides of Bosnia and Herzegovina and Croatia that integrates offshore 2D seismic data, borehole data, fieldwork and remote sensing to determine style of deformation, and paleogeographic evolution of this portion of the belt.The balanced and restored cross-section revises the traditional view, proposing a mixed thin-skinned/thick-skinned tectonic model that emphasizes the role of deep-seated structures and salt tectonics in shaping the region, with much less shortening than previous models. Salt tectonics, involving the deformation of evaporite layers, plays a critical role both in the passive margin stage and its subsequent inversion, localising the deformation and controlling the structural style. In this revised tectono-stratigraphic framework, potential scenarios for bauxite generation, accumulation and preservation are outlined. The combination of surface processes and tectonic activity creates zones where bauxite deposits are likely to be concentrated, both at local (thrust ramp anticlines, diapir roof uplift or extensional footwall uplift) and regional (see level fluctuation, forebulge migration) scales. Understanding these scenarios not only enhances the exploration potential in the Dinarides but also offers valuable analogues for bauxite exploration in other fold-and-thrust belts worldwide.

The Zagros foldbelt - foreland system in SW Iran is a prolific hydrocarbon province with known reserves of more than 90 billion brl of oil and 800 TCF of natural gas. Establishing the structural style of folding in the Zagros area presents a major challenge due both to the geographical extent of the foldbelt, which is some 1600 km long in total, and the presence of marked lateral variations in fold style related to the complex regional tectonic history. In addition, while numerous high-quality structural studies of the Zagros have been completed over the last 20 years, they support a variety of different interpretations and are therefore $$difficult to synthesize. In this paper, we review the general structural style of the Zagros fold-and-thrust belt in SW Iran, and in particular the style of folding in the Lurestan arc, Dezful embayment, Izeh Zone and Fars arc. We summarise relationships between folding in these areas and fracture development, and investigate the timing of folding and the interaction between NW-SE oriented "Zagros" folds and north-south oriented "Arabian" folds. Finally, we briefly assess the implications of fold style for petroleum systems in the Zagros area. Although no new data are presented in this paper, a series of unpublished maps are used to illustrate the main results and include: a map showing the extent of the main detachment levels across the Lurestan, Dezful and Fars structural domains; two palaeotectonic maps (for Late Cretaceous - Paleocene and Miocene - Pliocene times, respectively), showing the position of the deformation fronts of the Zagros and the North Oman thrust systems and their potential spatial and temporal relationship with folding; and a set of four maps showing the distribution of reservoir rocks which are grouped by age into the Permian - Triassic Dehram Group, the Late Jurassic - Early Cretaceous Khami Group, the Late Cretaceous Bangestan Group, and the Oligocene - Miocene Asmari Formation. In addition, for the Lurestan, Dezful and Fars structural domains, a series of regional cross-sections at the same scale are presented and discussed.Most of the data in this review paper were acquired in order to gain an improved understanding of the petroleum systems in the Zagros area; however the data are used here to investigate a range of interacting processes including tectonics, sediment deposition and subsurface fluid flow in the development of the fold-and-thrust belt and its associated foreland basins. The resulting synthesis is intended to provice a starting point for future tectonostratigraphic and hydrocarbon-related studies which will make use of both existing and new multidisciplinary techniques to constrain the results. The knowledge acquired and the techniques used will be of benefit in future challenges including the identification of subsurface reservoirs suitable for the permanent storage of CO2 to mitigate the effects of climate change.

Abstract The Central High Atlas of Morocco is a double verging major diapiric province encompassing SW-NE trending salt-related ridges and Lower to Middle Jurassic deposits over synclines (minibasins) in between them. Typically, Pliensbachian and Bajocian platform carbonates flanking diapirs exhibit partial dolomitization in the vicinity of the diapir wall. The interpretation of the diagenetic products and diagenetic evolution of these dolomitized carbonates may be complex due to different fracture patterns, brecciation, fluid pathways, heterogeneities, localized uplift associated with diapiric activity, among others. The present work focuses on the dolomitization affecting Late Aalenian-Bajocian platform carbonates flanking the Tazoult salt wall, localized in the center of the Central High Atlas. Analytical work includes standard microscopy, cathodoluminescence and 𝛅13C–𝛅18O isotopic analyses. A paragenetic sequence is discussed to reconstruct the diagenetic evolution of the flanking platform carbonates. The results highlight the major influence of diapirism and igneous intrusions on the fluid circulation. Moreover, the present work complements a previous work related to the Liassic successions flanking the Tazoult salt wall.

Critical raw materials are essential for the development of our society. However, most shallow ores have already been exploited and only deep targets remain unexplored. This work aims to apply indirect geophysical techniques to the San Finx Sn-W deposit (A Coruña) in order to get further constrains of its deep structure and geometry. Accordingly, a magnetic and a gravity survey have been carried out in the area (SE of Noia, A Coruña), at the southern part of the Malpica-Tui Complex. The resulting absolute magnetic anomaly and the relative gravity anomaly have been studied analytically and through 2-2.75D forward modeling. Results indicate that, the sampling interval (~1 km) is too high to characterize the anomalies related to the Sn-W mineralization. Contrarily, they show the potential field imprint of the regional Variscan tectonics. To better assess the relationship between the regional Variscan tectonics and the mineralization, a higher resolution survey should be acquired to detect this deposit.

Los deslizamientos y desprendimientos son un peligro común en áreas montañosas como los Pirineos. Aun así, en ocasiones han sido poco estudiados por la dificultad de acceso y, por tanto, la dificultad en la adquisición de datos, y la baja densidad de población en estas zonas. La Tartera de Cambrils, en la comarca del Solsonès, Cataluña, es un canchal producto de antiguos deslizamientos y desprendimientos de roca que ponen en peligro infraestructuras del pueblo de Cambrils, con una concurrencia creciente debido al incremento de actividades turísticas en la zona. Este estudio quiere determinar los procesos que causaron los deslizamientos iniciales, los procesos que ocurren en la ladera hoy en día y los factores que los causan. Para cumplir este objetivo, se ha consultado información bibliográfica y se ha llevado a cabo trabajo de campo para construir una cartografía geológica y geomorfológica, y se han adquirido datos LiDAR, con un Escáner Laser Terrestre, y fotografías del talud. Con los datos LiDAR y las fotografías se producen nubes de puntos tridimensionales, a partir de las que se estudian las discontinuidades y se analiza la estabilidad del talud. La continuidad, buzamiento y separación de la estratificación y la fracturación de la roca, dificultan el deslizamiento planar de bloques de roca y, por el contrario, facilitan el deslizamiento en cuña y el vuelco. El análisis de las discontinuidades permite estimar la posibilidad de futuros desprendimientos de roca sobre las distintas infraestructuras y proporciona datos fundamentales para planear futuras medidas de protección.

Landslides and rockfalls are a common hazard in mountain areas like the Pyrenees. However, due to the difficulty ofaccess and therefore ofdata acquisition, and the low density ofpopulation they are poorly studied. The Tartera de Cambrils, is located in a small town in the Solsones 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 saltflats called "El Sall" (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 causativefactors. 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, andphotographs in order to produce three-dimensional point clouds. We also analyse the rock-cle. 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 rockfronts of decametric volume along the main scarp and on the scree. These rockfronts 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 ofprotection measures.

Platform carbonates diagenesis in salt basins could be complex due to potential alterations of fluids related and non-related to diapirism. This paper presents the diagenetic history of the Hettangian to Pliensbachian platform carbonates from the Tazoult salt wall area (central High Atlas, Morocco). Low structural relief and outcrop conditions allowed to define the entire diagenetic evolution occurred in the High Atlas diapiric basins since early stages of the diapiric activity up to their tectonic inversion. Precipitation of dolomite and calcite from both warmed marine-derived and meteoric fluids characterised diagenetic stages during Pliensbachian, when the carbonate platforms were exposed and karstified. Burial diagenesis occurred from Toarcian to Middle Jurassic, due to changes of salt-induced dynamic related to increase in siliciclastic input, fast diapir rise and rapid burial of Pliensbachian platforms. During this stage, the diapir acted as a physical barrier for fluid circulation between the core and the flanking sediments. In the carbonates and breccias flanking the structures, dolomite and calcite precipitated from basinal brines, whereas carbonate slivers located in the core of the structure, were affected by the circulation of Mn-rich fluids. The final diagenetic event is characterised by the income of meteoric fluids into the system during uplift caused by Alpine orogeny. These results highlight the relevant influence of diapirism on the diagenetic modifications in salt-related basins in terms of diagenetic events and involved fluids.

We present the first regional balanced and restored sections across the northwestern part of the Zagros Fold-and-Thrust Belt in Kurdistan Region of Iraq and a 2D kinematic model that illustrates the evolution of the belt since Late Cretaceous time. The balanced cross-section, based on surface and sub-surface data, is characterized by multi-detachment folds detached above a Lower Triassic basal ductile level, with intermediate detachment levels that induced internal complexities like accommodation thrusting and/or disharmonic folding. Our work suggests that the two main structural steps in the detachment level in the High Folded Zone may be related to low-angle thrusts rooted at the brittle/ductile transition. Growth strata of Late Cretaceous and Paleocene times have been recognized for the first time in the Kurdistan Fold-and-Thrust Belt. This allows us to constrain timing of deformation and to estimate the evolution of the shortening and the advance of the deformation front since Late Cretaceous. Deformation of the Zagros belt is characterized by a combination of thin- and thick-skinned tectonics that reactivated the Late Cretaceous-Paleogene obduction belt.

The subsidence evolution of the Tethyan Moroccan Atlas Basin, presently inverted as the Central High Atlas, is characterized by an Early Jurassic rifting episode, synchronous with salt diapirism of the Triassic evaporite‐bearing rocks. Two contrasting regions of the rift basin – with and without salt diapirism – are examined to assess the effect of salt tectonics in the evolution of subsidence patterns and stratigraphy. The Djebel Bou Dahar platform to basin system, located in the southern margin of the Atlas Basin, shows a Lower Jurassic record of normal faulting and lacks any evidence of salt diapirism. In contrast, the Tazoult ridge and adjacent Amezraï basin, located in the centre of the Atlas Basin, reveals spectacular Early Jurassic diapirism. In addition, we analyse alternative Central High Atlas post‐Middle Jurassic geohistories based on new thermal and burial models ( GENEX ® 4.0.3 software), constrained by new vitrinite reflectance data from the Amezraï basin. The comparison of the new subsidence curves from the studied areas with published subsidence curves from the Moroccan Atlas, the Saharan Atlas (Algeria) and Tunisian Atlas show that fast subsidence peaks were diachronous along the strike, being younger towards the east from Early–Middle Jurassic to Late Cretaceous. This analysis also evidences a close relationship between these high subsidence rate episodes and salt diapirism.

Fieldwork and remote-sensing data from the Siah Kuh anticline, simply folded belt, Zagros, Iran indicate that specific structures and fracture systems formed during the development of its sigmoidal shape, and that conceptual fracture models developed for cylindrical folds are inadequate for the correct evaluation and development of hydrocarbon accumulations in this type of anticline. The sigmoidal shape of the Siah Kuh anticline was achieved in the Pliocene due to vertical axis rotations of an already existing anticline. These rotations promoted the development of (1) two systems of normal faults in the outer arcs of the sigmoidal shape, (2) a low-angle thrust, and (3) the north–south Danan anticline in the inner arc of its easternmost bend. The passive margin to syn-folding structures, typically observed in nearby cylindrical and periclinal anticlines, predated the development of the sigmoidal shape and were passively rotated into the segments of the anticline. The sigmoid-related structures are spatially, geometrically, and kinematically related to the bends of the anticline trend, hence they can be predicted and modeled in the subsurface. The sigmoid-related normal faults have a great potential to preserve porosity and promote localized high flow rates or early water breakthrough. However, if they cut through thin reservoir and seal units, sigmoid-related thrusts and normal faults might compromise lateral reservoir continuity and seal integrity. The results of this study can help in reducing risks and uncertainty in the evaluation and development of business opportunities in secondary sigmoidal anticlines within the Zagros or any other fold-thrust belt.

Alpine Folded Belts and Extensional Basins (GRW events) , 15-16 march, 2018, Granada, Spain

Various studies have demonstrated the intrinsic interrelationship between tectonics and sedimentation in salt-related rift basins during extension as well as during their inversion by compression. Here, we present seven brittle-ductile analogue models to show that the longitudinal or transverse progradation of sediment filling an elongate extensional basin has a substantial impact on the growth of diapirs and their lateral geometrical variations. We use five extensional models to reveal how these prograding systems triggered diapir growth variations, from proximal to distal areas, relative to the sedimentary source. In the models, continuous passive diapir walls developed, after a short period of reactive-active diapiric activity, during syn-extensional homogeneous deposition. In contrast, non-rectilinear diapir walls grew during longitudinal prograding sedimentation. Both longitudinal and transverse post extensional progradation triggered well-developed passive diapirs in the proximal domains, whereas incipient reactive-active diapirs, incipient roller-like diapirs, or poorly developed diapirs were generated in the distal domains, depending on the modelled sedimentary pattern. Two models included final phases of 6% and 10% shortening associated with basin inversion by compression, respectively, to discriminate compressional from purely extensional geometries. With the applied shortening, the outward flanks of existing diapir walls steepened their dips from 8 degrees-17 degrees to 30 degrees-50 degrees. Likewise, 6% of shortening narrowed the diapir walls by 32%-72%, with their fully closing (salt welds) with 10% of shortening. We compare our results with the distribution of salt walls and minibasins of the Central High Atlas diapiric basin in Morocco, which was infilled with a longitudinally prograding mixed siliciclastic and carbonatic depositional sequence during the Early-Middle Jurassic with a minimum thicknesses of 2.5-4.0 km. (C) 2017 Elsevier Ltd. All rights reserved.

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.

The principal objective of this paper is to summarize the large data set gathered in the last few years on the Early-Middle Jurassic diapiric evolution in the well-exposed Central High Atlas in Morocco. Field data on both structural geology and sedimentology of halokinetic sequences, significant remote sensing mapping using good quality satellite images, thermal modeling and subsidence analysis, balanced and restored cross sections, and analog modeling allowed us to construct an integrated tectono-sedimentary interpretation of a salt-related rift basin. Three characteristic regions are summarized here to show the tectonic and diapiric evolution of the study region: Tazoult, Azourki, and Imilchil. Salt ridges (Tazoult, Jbel Azourki, and Tassent salt walls) above blind basement faults developed a polygonal array bounding thick synclines (minibasins) with different orientations. The Imilchil minibasins show diachronous age of their infill, which is a typical characteristic of diapiric regions. The Tazoult and Jbel Azourki salt walls developed an allochthonous salt body starting during the Late Pliensbachian-Aalenian time. Although only Lower and Middle Jurassic halokinetic sedimentary sequences are preserved in most of the Central High Atlas, younger synclines (minibasins) along the northern boundary of the Atlas (Demnate region) show development of Late Jurassic and Early Cretaceous minibasins. At the larger scale, the diachronous evolution of the extension and diapirism along the Atlas Basin suggests that diapirism and salt withdrawal play an important role during the development of the High Atlas in Morocco, Saharan Atlas in Algeria, and Tunisian Atlas in a similar way as it is fabulously imaged across the onshore and offshore Atlantic Moroccan basins.

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 Sedimentaria> de la Generalitat de Catalunya (2014GSR251). We are grateful to Statoil for its support and permission to publish this study.