Abstracted/indexed

Many of the world's hydrocarbon resources are found in rifted sedimentary basins. Some rifts experience multiple phases of extension and inversion. This results in complicated oil and gas generation, migration, and entrapment histories. We present examples of basins in the Western Desert of Egypt and the western Black Sea that were inverted multiple times, sometimes separated by additional phases of extension. We then discuss how these complex deformation histories impact exploration campaigns.

The geothermal potential of a carbonate reservoir in the Rhine-Ruhr area, Germany, was investigated by field and laboratory investigations. The carbonate layer of interest is approx. 150 m thick; located at 4 to 6 km depth; and might extend below Essen, Bochum, and Dortmund. We proposed focusing on discontinuities striking NNW–SSE for geothermal applications, as these are the most common, strike in the direction of the main horizontal stress, and dominate reservoir fluid flow.

We develop a two-step methodology combining multiple surface deformation measurements above a salt extraction site (Vauvert, France) in order to overcome the difference in resolution and accuracy. Using this 3-D velocity field, we develop a model to determine the kinematics of the salt layer. The model shows a collapse of the salt layer beneath the exploitation. It also identifies a salt flow from the deepest and most external part of the salt layer towards the center of the exploitation.

In this work, we combined different imaging and experimental measuring methods for analysis of cross-scale effects which reduce permeability of tight reservoir rocks. Simulated permeability of digital images of rocks is often overestimated, which is caused by non-resolvable clay content within the pores of a rock. By combining FIB-SEM with micro-XCT imaging, we were able to simulate the true clay mineral abundance to match experimentally measured permeability with simulated permeability.

Using seismic array methods, 63 events were located in the Rodrigues–CIR region, not reported by any global network, most of them being off the ridge axis. The lack of seismicity along this section of the CIR, as observed from global data and this study, can possibly be attributed to the presence of partially molten mantle beneath Rodrigues Ridge. The results will be of interest for a broad range of geoscientists interested in the tectonic evolution of Indian Ocean and plume–crust interaction.

We present an innovative workflow for the statistical analysis of fracture data collected along scanlines. Our methodology is based on performing non-parametric statistical tests, which allow detection of important features of the spatial distribution of fractures, and on the analysis of the cumulative spacing function (CSF) and cumulative spacing derivative (CSD), which allows the boundaries of stationary domains to be defined in an objective way.

In this work we provide a 2D finite-element modelling of the stress field conditions around the Fuego de Colima volcano (Mexico) in order to test the response of the commercial Linear Static Analysis software to increasingly different geological constraints. Results suggest that an appropriate set of geological and geophysical data improves the mesh generation procedures and the degree of accuracy of numerical outputs, aimed at more reliable physics-based representations of the natural system.

We identified several problems in Urbani et al. (2020), showing that their model does not conform to the age and location of faulting, identification and delimitation of uplifted areas and apical depressions, temperature and lithological well log, and stratigraphic and radiometric data. Published data indicate that the pressurization of the Los Humeros volcanic complex (LHVC) magmatic–hydrothermal system driving resurgence faulting occurs at a greater depth.

Spatially continuous strain responses in two monitoring wells induced by a well-drilling process were monitored using high-resolution fiber-optic distributed strain sensing (DSS). The modeling results suggest that the strain polarities and magnitudes along the wellbores may be indicative of the layered-permeability structure or heterogeneous formation damage. The performance and value of DSS as a novel hydrogeophysical tool for in situ subsurface monitoring are emphasized.

The Kallipetra Basin, formed in the Late Cretaceous on the reworked Pelagonian–Axios–Vardar contact in the Hellenides, is described for the first time. We document how and when the basin evolved in response to tectonic forcings and basin inversion. Cenomanian extension and basin widening was followed by Turonian compression and basin inversion. Thrusting occurred earlier than previously reported in the literature, with a vergence to the NE, at odds with the regional SW vergence of the margin.

A geochemical comparison of early Palaeozoic felsic magmatic episodes throughout the south-western European margin of Gondwana is analysed and includes data from the Iberian Massif, the Eastern Pyrenees, southern France and Sardinia. This dataset favours partial melting of sediments and/or granitoids in the lower continental crust during extensional movements related to the opening of the Rheic Ocean.

Fluids (like water or gases) within the Earth's crust often flow and interact with rock through fractures. The efficiency with which these fluids may flow through this void space is controlled by the width of the fracture(s). In this study, three different physical methods to measure fracture width were applied and compared and their predictive accuracy was evaluated. As a result, the mobile methods tested may well be applied in the field if a number of limitations and requirements are observed.

Processes associated with open pores can change the physical properties of rocks and cause earthquakes. In borehole samples from the Alpine Fault zone, we show that many pores in these rocks were filled by weak materials that can slide easily. The amount of open spaces was thus reduced, and fluids circulating within them built up high pressures. Both weak materials and high pressures within pores reduce the rock strength; thus the state of pores here can trigger the next Alpine Fault earthquake.

Our reactive transport models show that high-temperature fault-controlled dolomite can form from mixed convection and act as a sink for Mg in the circulating seawaters. This provides new perspectives to enhance understanding of mechanisms and controls on dolomitisation, geometry, and spatial distribution of dolomite bodies within faulted and fractured systems, which has important implications for modelling of systems ranging from geothermal resources to ore formation and carbonate diagenesis.

The chronology of historical earthquakes (from historical documents and geological evidence) is still poorly constrained in the western Himalaya. We carried out a field investigation in SW Bhutan along the India–Bhutan border. Our analysis reveals that Bhutan has experienced at least five great earthquakes during the last 2600 years. Coseismic slip values along the Main Himalayan Thrust for most events reach at least 13 m and suggest that associated magnitudes are in the range of M_w 8.5–9.

With computer simulations, we study the interplay between thermo-mechanical processes in the lithosphere and the underlying upper mantle during a long-term (> 100 Myr) tectonic cycle of extension–cooling–convergence. The intensity of mantle convection is important for (i) subduction initiation, (ii) the development of single- or double-slab subduction zones, and (iii) the forces necessary to initiate subduction. Our models are applicable to the opening and closure of the western Alpine Tethys.

The Sobrado unit represents an allochthonous tectonic slice of exhumed high-grade metamorphic rocks formed during a complex sequence of orogenic processes in the middle to lower crust. We have combined U–Pb geochronology and REE analyses (LASS-ICP-MS) of accessory minerals in migmatitic paragneiss (monazite, zircon) and mylonitic amphibolites (titanite) to constrain the evolution. A Middle Devonian minimum age for HP metamorphism has been obtained.

This study assesses the influence of basement rocks on the fluid chemistry during deformation in the Pyrenees and provides insights into the fluid regime in the NE part of the Iberian Peninsula.

The injection of fluids (like wastewater or CO₂) into the subsurface could cause earthquakes when existing geological faults inside the reservoir are (re-)activated. To assess the hazard associated with this, previous studies have conducted experiments in which fluids have been injected into centimetre- and decimetre-scale faults. In this work, we analyse and model these experiments. To this end, we propose a new approach through which we extract the model parameters that govern slip on faults.

We studied the characteristics of fracture systems in the Devonian rocks of the Orcadian Basin in Caithness. These mineral-filled fractures have properties that may be used to predict the size and spatial arrangement of similar structures in offshore basins. This includes the Clair field in the Faroe–Shetland Basin.

We present new U–Pb age data to provide insights into the source of sediment for the Molasse Sedimentary Basin in Switzerland. The paper aims to help shed light on the processes that built the Central Alpine Mountains between ~35 and ~15 Ma. A primary conclusion drawn from the results is that at ~21 Ma there was a significant change in the sediment sources for the basin. We feel this change indicates major tectonic changes within the Central Alps.