Seven sections, covering the upper Albian to lowermost Turonian, have been correlated from full-marine to continental-dominated deposits across a passive margin, along a transect 425 km long, from the present-day Atlantic coast to the "Pre-African Trough" between the Anti-Atlas and the High-Atlas. The thickness of the Cenomanian succession changes from around 500 metres in the fully marine sections to 250 metres in mostly continental facies in the western High-Atlas, about 150 km updip, to a few tens of metres in the Bou Tazoult area. The strata thicken again eastwards into the Pre-African Trough where they can be traced without major facies changes to the Kem Kem embayment and to the Bechar area in Algeria. Over all this eastern area, continental facies are overlain by the fully-marine shallow-water deposits of the Cenomanian-Turonian boundary interval. A first major conclusion is that fluvial aggradation in high-frequency transgressive-regressive sequences is coeval with the seaward-shift of the shoreline, in accordance with the genetic sequence stratigraphic model of GALLOWAY (1989). Both the flatness of the depositional profile and the corresponding very low energy of the marine environment during the transgressions account for the blanket of red continental clays on top of marine facies in updip depositional sequences, which is then preserved under the marine transgressive surface of the next sequence.

Dealing with the ill-posed and non-unique nature of the non-linear geophysical inverse problem via local optimizers requires the use of some regularization methods, constraints, and prior information about the Earth's complex interior. Another difficulty is that the success of local search algorithms depends on a well-designed initial model located close to the parameter set providing the global minimum. On the other hand, global optimization and metaheuristic algorithms that have the ability to scan almost the entire model space do not need an assertive initial model. Thus, these approaches are increasingly incorporated into parameter estimation studies and are also gaining more popularity in the geophysical community. In this study we present the Barnacles Mating Optimizer (BMO), a recently proposed global optimizer motivated by the special mating behavior of barnacles, to interpret magnetic anomalies. This is the first example in the literature of BMO application to a geophysical inverse problem. After performing modal analyses and parameter tuning processes, BMO has been tested on simulated magnetic anomalies generated from hypothetical models and subsequently applied to three real anomalies that are chromite deposit, uranium deposit and Mesozoic dike. A second moving average (SMA) scheme to eliminate regional anomalies from observed anomalies has been examined and certified. Post-inversion uncertainty assessment analyses have been also implemented to understand the reliability of the solutions achieved. Moreover, BMO’s solutions for convergence rate, stability, robustness and accuracy have been compared with the solutions of the commonly used standard Particle Swarm Optimization (sPSO) algorithm. The results have shown that the BMO algorithm can scan the model parameter space more extensively without affecting its ability to consistently approach the unique global minimum in this presented inverse problem. We, therefore, recommend the use of competitive BMO in model parameter estimation studies performed with other geophysical methods.

Deeply buried sandstone reservoirs are targeted in the Upper Rhine Graben (URG) for geothermal and hydrocarbon resources. These reservoirs are affected by a convective heat flow along fault zones and have a complex diagenetic and deformation history recorded in their paragenetic sequence. Here, the focus is made on siderite and barite cementation characterisation, which trace paleo geothermal circulations within the fracture network affecting the Buntsandstein Gp. sandstones. A double approach on geochemistry and fracture network features is used to characterise fluid-flow episodes in the rift basin and on its shoulders. Barite sulphur isotopic signature suggests a common source for all the locations. However, Rare Earth Elements distribution patterns, oxygen isotopic ratios, and fluid inclusion study suggest two distinct flow regimes for fluids associated with barite precipitation along the shoulders and at depth in the middle of the graben. The barite has a higher content in total REE and contains non-saline fluid inclusions on the graben shoulders, suggesting that fluid circulations within the border faults interact with sulphate rich layers and precipitate at temperature above 150 °C. In deep-seated samples from the central part of the basin, barite fluid inclusions show a wide range of salinities, suggesting a higher contribution of sedimentary brines and precipitation at lower temperatures (< 150 °C). According to their REE signature, these barite mineralisations are associated with siderite and apatite with a diagenetic source. A conceptual model for fluid circulation within the basin is built from this new dataset. Fast and deep down- and up-flows occur along the major border faults, locally leaching evaporitic horizons. A part of the infiltrated meteoric waters reaches the centre of the basin, where it then mixes with the brines in sedimentary. This new characterisation of fluid pathways in the targeted reservoir brings insights into geothermal circulation compartmentalisation at the basin scale.

Airborne magnetic surveys are common in geosciences. High‐precision surveys are usually performed at a low altitude, draping the topography, using scalar absolute magnetometers and active compensation systems to correct the disturbances generated by the carrier. Another solution is to measure the total magnetic intensity using vector magnetometers, which allows compensation for aircraft fields to be calculated directly, without compensation systems. This study uses data of an industrial airborne survey and of a vector magnetometer survey with a small overlapping area in the Vosges (France) to compare both data sets and shows that both solutions provide results of the same overall precision. This paper also addresses the issue of combining fixed altitude and draped level data sets as well as topographic effect management by proposing an equivalent source interpolator based on a set of simple dipole sources. A synthetic case shows that the equivalent source interpolator allows to compute grids of the magnetic anomaly as well as potential field transforms from a draped data set with an error level a few orders of magnitude lower than could be obtained with minimum curvature, a classically applied interpolator. The interpolator is also tested on a case study in the Vosges massif of which geological interpretation is presented in Bertrand et al. (2020, https://doi.org/10.1029/2019JB017688). The results confirm the observations made on the synthetic case and show that the equivalent source interpolator is more tolerant to navigation errors (altitude) than minimum curvature and allows more rigorous computation of potential field transforms of draped data sets.

Hosting both tsunami earthquakes and slow slip events at shallow depth, the northern Hikurangi margin has motivated strong research efforts over the last two decades to better understand the relation between fluid pressure and fault mechanical behavior. Recently, IODP Expeditions 372 and 375 drilled, cored, and logged the basin entering this subduction zone providing a unique opportunity to characterize initial hydrogeological and petrophysical properties that drive seismic hazards along the margin. We inventory bound and interstitial fluid contents and assess the compaction state of the heterogeneous incoming sequence by correcting shipboard total connected porosity from the bound water content that typically characterizes clay‐rich sediments. By combining mercury injection capillary pressure, nuclear magnetic resonance, and nitrogen gas adsorption, we further document the evolution of pore structure with increasing depth. We also compare porosity data at the logging and sample scales. Both logging and laboratory data evidence contrasted porosity, pore structure, and fluid distribution across the entering section. Shallow macroporous siliciclastic units show very low bound water content and undergo compaction‐induced dewatering as they are normally consolidated during burial. In contrast, mesoporous volcaniclastic Hikurangi Plateau facies are characterized by high potential for bound water release from smectite, zeolite, and opal dehydration at greater depths. They mostly exhibit very low permeability except potentially in uncemented highly porous intervals where the décollement may initiate. Macroporous to mesoporous pelagic carbonates sandwiched in between exhibit mixed behavior and may also host the future décollement, similarly to the southern part of the margin.