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The Qiulitage fold and thrust belt (QFTB) is situated in the Kuqa Depression, exhibiting spectacular salt structures with well-defined geometric and kinematic characteristics and thereby playing a significant role in advancing the study of salt structures worldwide. This research, based on regional geology, well logging, and newly acquired three-dimensional seismic data, applies principles of salt-related fault structures to interpret seismic data and restore structural equilibrium in the Qiulitage fold and thrust belt within the Kuqa Depression by conducting quantitative studies on structural geometry and kinematics. Results indicate clear differences in salt structures between the eastern and western segments of it, vertically divided into upper salt, salt layer, and lower salt and horizontally into four parts. The Dina segment features a single-row basement-involved thrust fault, the East QFTB segment displays detachment thrust faults involving cover layers, the Central QFTB segment exhibits detachment thrust faults involving multiple rows of cover layers, the leading edge forms structural wedges, and the West QFTB segment develops blind-thrust faults. During the deposition of the Kangcun formation, the eastern profile experiences an 18% shortening rate, 14% in the central part, and 9% in the western part. For the Kuqa formation, the eastern profile experiences a 10% shortening rate, 9% in the central part, and 3% in the western part, indicating more significant deformation in the east than in the west. Quantitative statistical analysis reveals that different types of detachments, paleogeomorphology, and northeast-directed compressive stress exert control over the Qiulitage fold-thrust belt. [ABSTRACT FROM AUTHOR]

Based on the analysis and interpretation of gravity and magnetic field anomalies, we studiedthe peculiarities of fault tectonics, structural-tectonic structure (including salt dome tectonics) of the Transcarpathian trough. We identified signs of the manifestation of deep faults and other large structural-tectonic elements in anomalies of gravity and magnetic fields. We then traced these structural-tectonic units by comparing the morphology, intensity, dimensions, and directions of the typical anomalous zones in the gravitational and magnetic fields with the tectonic structure of the region. We used digital maps of gravitational and magnetic fields; averaging transforms and relief-shadow images, we mapped local gravimagnetic anomalies. Analysis of the spatial structure of the original gravimagnetic fields and their transforms and structural-tectonic maps yielded a reflection of large tectonic elements of fault tectonics, anticlinal and salt dome structures in the gravimagnetic fields. Based on gravimagnetic data, the tectonic structure of the Transcarpathian trough was clarified, and the boundaries of tectonic zones and microplates were traced. The zone of the Transcarpathian deep fault is identified as a tectonic zone traced by a band of intense local positive anomalies of the gravity field along the Flysch Carpathians to the border of the Marmarosh massif. It is limited by high gradients from the southwest and northeast and is a reflection of the Pieniny and Marmarosh rock zones. The zone of the Transcarpathian deep fault is considered a suture zone of the Inner and Flysch Carpathians. In the structure of the anomalous gravity field of the Transcarpathian trough, a number of local anomalies associated with salt stocks, as well as individual anomalies, expected to be connected to salt-bearing deposits, werefound. We confirmed the effectiveness of gravimagnetic methods in the geological conditions of the Transcarpathian trough to detect anticlinal structures, basement protrusions, which create favorable conditions for oil and gas traps in sedimentary strata. Interpreting anomalous gravimagnetic fields in combination with geological and tectonic materials is an important condition for the integral process of studying the geological and tectonic structure of the Earth’s crust in the Transcarpathian region.

Subsurface salt flow is driven by differential loading, which is typically caused by tectonics or sedimentation. During glaciations, the weight of an ice sheet represents another source of differential loading. In salt-bearing basins affected by Pleistocene glaciations, such as the Central European Basin System, ice loading has been postulated as a trigger of young deformation at salt structures. Here, we present finite-element simulations (ABAQUS) with models based on a simplified 50-km long and 10-km-deep two-dimensional geological cross-section of a salt diapir subject to the load of a 300-m-thick ice sheet. The focus of our study is to evaluate the sensitivity of the model to material parameters, including linear and non-linear viscosity of the salt rocks and different elasticities. A spatially and temporarily variable pressure was applied to simulate ice loading. An ice advance towards the diapir causes lateral salt flow into the diapir and diapiric rise. Complete ice coverage leads to downward displacement of the diapir. After unloading, displacements are largely restored. The modelled displacements do not exceed few metres and are always larger in models with linear viscosity than in those with non-linear viscosity. Considering the low stresses caused by ice-sheet loading and the long time-scale, the application of linear viscosity seems appropriate. The elastic parameters also have a strong impact, with lower Young's moduli leading to larger deformation. The impact of both the viscosity and the elasticity highlights the importance of a careful parameter choice in numerical modelling, especially when aiming to replicate any real-world observations. [ABSTRACT FROM AUTHOR]

The present paper deals with a geochemical investigation (TOC, Rock–Eval pyrolysis, and GC–MS) carried out on two potential mid-Cretaceous (Albian lower Fahdene and Cenomanian–Turonian Bahloul) source rocks and natural oil seeps collected from outcrops and mine boreholes located around the three extrusive salt structures of Ech-Cheid, Fej Lahdoum, and Boukhil, belonging to the Triassic domes zone of northern Tunisia. Rock–Eval pyrolysis results indicate the presence of moderate to good and moderate to excellent quantities of organic matter (OM) of oil–gas type II/III (means TOC: 0.90 wt.%, HI: 180 mg HC/g TOC, and PP: 2.00 mg HC/g rock) and oil-prone type II (means TOC: 3.5 wt.%, HI: 458 mg HC/g TOC, and PP: 20 mg HC/g rock) kerogens for the Fahdene and the Bahloul Formations (Fms), respectively. The thermal maturity of the OM preserved in these source rocks varies between late diagenesis and the late oil window depending mainly on the basin architecture marked by the presence of paleohighs (Triassic salt domes and horsts), grabens, half-grabens, and tilted blocks that controlled the varying degrees of subsidence. Gas chromatography-mass spectrometry (GC–MS) analysis of source rock extracts (Bitumen) and oil seeps and correlations with hierarchical cluster analysis (HCA) using biomarkers parameters (Diasteranes C27βαS/C27ααS and Hopanes C29H/C30H ratios) suggest that the collected oil seep samples were sourced by the Fahdene and the Bahloul Fms. The spatio-temporal oil seeps distribution and associated tectonics indicate that several faults of NW–SE, N-S, E-W, and NE-SW trendings have facilitated oil migration from these source rocks to favorable reservoirs of middle-Turonian Bireno, Coniacian Douleb, and Campanian–Maastrichtian Abiod carbonates as well as a Miocene Oum Dhouil sandstone. These mid-Cretaceous source rocks and associated reservoirs, as well as overlaying argillaceous seals and traps (Flanks of diapirs, uplifted paleohighs, and anticlines), as essential elements, in addition to oil migration pathways and accumulation processes attest to the presence of active conventional petroleum systems in northern Tunisia. This could help guide petroleum exploration activities around subsurface diapir structures analogous. [ABSTRACT FROM AUTHOR]

Analysis of the identification of hydrocarbon generation foci (hydrocarbon kitchens) by state-of-the-art methods has been carried out. Radial–concentric structures in the basement of the East European Craton as potential hydrocarbon kitchens are discussed. The seismic geological signs and the tectonic setting of their inception and development were studied with reference to the southwestern part of Orenburg oblast. The article presents an interpretation of the time sections of regional seismic profiles shot in the study area using the method of successive approximations and detailing, as well as the results of analysis of geological–geophysical and remote sensing data. It was established that flower structures are present in the time sections of seismic profiles shot in the areas of geodynamically active hydrocarbon kitchens in the sedimentary cover. The Lower Permian salt of the Kungurian Stage forms large domes above hydrocarbon accumulations (the area of the East Orenburg geodynamically active hydrocarbon kitchen and oil and gas fields within the Cis-Uralian Foredeep and its junction with the East European Craton) or are upthrown within fault blocks (the area of the West Orenburg geodynamically active kitchen, oil and gas fields of the Sol-Iletsk arch). A chaotic, subvertically oriented, locally enhanced seismic record, which extends beneath the reflector, interpreted as the roof of basement rocks, has been noted below the roof of Devonian deposits within the areal extent of hydrocarbon pools. A sketch map of the basement fault network genetically related to neotectonic shear was compiled based on structural constructions, taking the configuration of hydrocarbon fields into account. The known hydrocarbon fields and structures identified by seismic surveys have a regular distribution inside four large radial–concentric structures. The constructions are confirmed by modern geotectonic process monitoring and interpretation of satellite image data. We assume that the centers of the structures are geodynamically active hydrocarbon kitchens and that hydrocarbon migration takes place along radial and concentric fault zones. By analogy with the Orenburg tectonic node, a few other large hydrocarbon accumulation centers have been identified, in which further oil and gas prospecting and exploration operations are advisable. [ABSTRACT FROM AUTHOR]

Accurate information on the subsurface temperature distribution is crucial for assessing a region’s geothermal potential and upcoming project planning. However, previous temperature models mostly suffer from low resolution structural models and unknown temperature gradient - lithology relations. Therefore, this study presents a new strategy for subsurface temperature modelling, applied to the Altmark region (North German Basin). It is based on a detailed structural model consisting of 31 base horizons between earth’s surface and Base Zechstein. 46 temperature logs were used for the derivation of mean temperature gradients for each model formation. The averaged temperature gradients vary between 20 and 56 K km-1 in the study area. To account for the strong influence of highly thermally conductive salt accumulations in the Zechstein Group, empirical models were developed in relation to Zechstein and supra-salt thicknesses. Temperatures were calculated using a one-dimensional top-to-bottom approach. The temperature model shows the dependencies of the temperature distribution in the subsurface on the thermal conductivities and thus the predominant lithologies of the model formations. Small-scale anomalies induced by salt pillows and diapirs lead to differences in the predicted temperatures of up to 15 K at same depth level. A comparison between measured and modelled temperatures showed that more than 90% of the temperature data deviations are below 5 K. The final model was compared with an existing large-scale model to evaluate the prediction quality. [ABSTRACT FROM AUTHOR]

The Sudanese Red Sea Basin is situated in a passive margin formed by a rift-drift transition between continental and oceanic systems. In this study, the gravity and magnetic data have been used to constrain the tectonic elements, major lineation trends, and the distribution of salt basins. 2D reflection seismic profiles were used to examine the tectonic boundaries, fault types, and salt structures of Block 13. The gravity anomalies showed two major north–south trending orientations of positive and negative residual gravity anomalies. Positive residual anomalies were interpreted to represent higher-density shale and carbonate deposits, whereas negative residuals were interpreted to mean salt deposits and sandstone. The magnetic map showed the anomalous total magnetic field, and the connected profiles allow identifying four significant zones with different magnetic patterns. The average trend of these zones can be classified into two groups: one trending northeast (45°) and the other trending northwest (315°). Although the salt deposits affect seismic data resolution, fault blocks and tectonic boundaries in the upper Wardan Formation (Upper Miocene phase) to lower Zeit Formation (Lower Pliocene) were interpreted using stratigraphic correlations. Growth and normal faults extend northeast to the southwest, with minor fault development identified in the Pliocene and Miocene strata in the southwestern part of the study area. At the same time, older normal faults cutting through the pre-Miocene salt succession were also detected. Also, the present work revealed salt structures such as salt domes and salt tongues. [ABSTRACT FROM AUTHOR]

Potential field data, reprocessed regional 2D seismic reflection profiles and 3D seismic tied to wells were used to study the late Devonian‐Permian development of the Nordkapp Basin in Barents Sea. The composite basin can be subdivided into the northeastern, central and southwestern segments that developed above a basement that contains elements of the Timanian and Caledonian regimes. The transition between the Timanian and Caledonian structures is positioned below the central basin segment. The rheological properties, locations, orientations and interaction of inherited structures together with two subsequent extensional phases, defined the presalt rift architecture and gave rise to seven subbasins within Nordkapp Basin. During the late Devonian‐early Carboniferous NE‐SW oriented extension, the basin consisted of two regional half‐grabens (northern and southern) separated by an interbasin ridge. During the late Carboniferous, the shift of extension direction to NW‐SE orientation reshaped the two regional half‐grabens. In particular, an interbasin transfer zone divided the northern regional half‐graben by separating its hinged‐margin portion (incipient northeastern segment) from the deeper part (incipient central segment). At the same time, the elevated interbasin ridge separated the incipient central and southwestern segments. Internally within the seven subbasins, the evolving structural elements including cross‐cutting master faults and structural highs have influenced the deposition and character of the Pennsylvanian‐lower Permian layered evaporite sequence and the distribution of subsequent salt structures. We suggest that the synrift to early postrift processes, relative depth of each subbasin, arrangement of the structural highs and depositional palaeo‐environment all controlled the thickness and facies of the layered evaporite sequence. The latter in combination with the presalt architecture comprised a laterally varying in thickness and character substratum that during the earliest Triassic influenced the sediment routings and deposition of the progradational system arriving in Nordkapp Basin. The study outcomes are pertinent and applicable to other salt‐influenced rift basins worldwide. [ABSTRACT FROM AUTHOR]

An extensive, reprocessed two‐dimensional (2D) seismic data set was utilized together with available well data to study the Tiddlybanken Basin in the southeastern Norwegian Barents Sea, which is revealed to be an excellent example of base salt rift structures, evaporite accumulations and evolution of salt structures. Late Devonian–early Carboniferous NE‐SW regional extensional stress affected the study area and gave rise to three half‐grabens that are separated by a NW‐SE to NNW‐SSE trending horst and an affiliated interference transfer zone. The arcuate nature of the horst is believed to be the effect of pre‐existing Timanian basement grain, whereas the interference zone formed due to the combined effect of a Timanian (basement) lineament and the geometrical arrangement of the opposing master faults. The interference transfer zone acted as a physical barrier, controlling the facies distribution and sedimentary thickness of three‐layered evaporitic sequences (LES). During the late Triassic, the northwestern part of a salt wall was developed due to passive diapirism and its evolution was influenced by halite lithology between the three‐LES. The central and southeastern parts of the salt wall did not progress beyond the pedestal stage due to lack of halite in the deepest evaporitic sequence. During the Triassic–Jurassic transition, far‐field stresses from the Novaya Zemlya fold‐and‐thrust belt reactivated the pre‐salt Carboniferous rift structures. The reactivation led to the development of the Signalhorn Dome, rejuvenated the northwestern part of the salt wall and affected the sedimentation rates in the southeastern broad basin. The salt wall together with the Signalhorn Dome and the Carboniferous pre‐salt structures were again reactivated during post‐Early Cretaceous, in response to regional compressional stresses. During this main tectonic inversion phase, the northwestern and southeastern parts of the salt wall were rejuvenated; however, salt reactivation was minimized towards the interference transfer zone beneath the centre of the salt wall. [ABSTRACT FROM AUTHOR]

Featured Application: This paper introduces a novel parallelized technique for potential-field-data modelling and inversion. Inversion of potential field data is a powerful tool for regional geophysical exploration, particularly in zones with complex geology that often require the integration of multiple sources of geophysical information. It is applicable in the exploration of oil reservoirs in environments with the presence of salt tectonics, in order to be able to define the geometry of subsalt geological features, which cannot be obtained by other more expensive methods such as seismics. Also, in the exploration of karst terrains, inversion of potential field high-resolution data is quite useful in order to determine the three-dimensional geometry of tunnels, caves, and caverns located in the near-surface, of great interest for estimating geological and geotechnical risks. Other potential applications are archaeology, volcanology, location of groundwaters, etc. Potential-field-data imaging of complex geological features in deepwater salt-tectonic regions in the Gulf of Mexico remains an open active research field. There is still a lack of resolution in seismic imaging methods below and in the surroundings of allochthonous salt bodies. In this work, we present a novel three-dimensional potential-field-data simultaneous inversion method for imaging of salt features. This new approach incorporates a growth algorithm for source estimation, which progressively recovers geological structures by exploring a constrained parameter space; restrictions are posed from a priori geological knowledge of the study area. The algorithm is tested with synthetic data corresponding to a real complex salt-tectonic geological setting commonly found in exploration areas of deepwater Gulf of Mexico. Due to the huge amount of data involved in three-dimensional inversion of potential field data, the use of parallel computing techniques becomes mandatory. In this sense, to alleviate computational burden, an easy to implement parallelization strategy for the inversion scheme through OpenMP directives is presented. The methodology was applied to invert and integrate gravity, magnetic and full tensor gradient data of the study area. [ABSTRACT FROM AUTHOR]

Central Tunisia is characterized by major fault systems, being ornamented by salt diapirs of the Late Triassic evaporite-rich interval. Salt movement began in the Late Triassic and continues to the present-day. Lasting halokinesis create pillows, diapirs, salt wall and salt-cored folds, sometimes, with collapse graben above. Salt diapir structures have been mapped and many regions collapsed diapirs are, perhaps, associated to salt removal. These structures were eroded resulting exposure and sub-aerial erosion by the Late Cretaceous to Paleogene uplift and post-Middle Miocene. The initial studies and findings related to salt structures in Tunisia suggesting a clear correlation between diapiric uplift and local tectonic structures. In particular, the N‒S and NW‒SE shortening trends during the Neogene and Quaternary folding strongly controlled the development of rows of diapirs and salt walls. The salt activities are controlled by tectonics as well as differential loading in the Triassic sediments over long distances, displaying that the mobilization of Triassic sediments covered the whole region and not just the zones near the single diapiric structures. Here we will focus also in the salt related plays and the associated petroleum systems with particular emphasis on trap types, reservoir and hydrocarbon migration pathways. Obviously, all these elements are linked together to certain degree and controlled by the salt tectonics. [ABSTRACT FROM AUTHOR]

The role of hydrogen in a future energy system with a high share of variable renewable energy sources (VRES) is regarded as crucial in order to balance fluctuations in electricity generation. These fluctuations can be compensated for by flexibility measures such as the expansion of transmission, flexible generation, larger back-up capacity and storage. Salt cavern storage is the most promising technology due to its large storage capacity, followed by pumped hydro storage. For the underground storage of chemical energy carriers such as hydrogen, salt caverns offer the most promising option owing to their low investment cost, high sealing potential and low cushion gas requirement. This paper provides a suitability assessment of European subsurface salt structures in terms of size, land eligibility and storage capacity. Two distinct cavern volumes of 500,000 m3 and 750,000 m3 are considered, with preference being given for salt caverns over bedded salt deposits and salt domes. The storage capacities of individual caverns are estimated on the basis of thermodynamic considerations based on site-specific data. The results are analyzed using three different scenarios: onshore and offshore salt caverns, only onshore salt caverns and only onshore caverns within 50 km of the shore. The overall technical storage potential across Europe is estimated at 84.8 PWh H2 , 27% of which constitutes only onshore locations. Furthermore, this capacity decreases to 7.3 PWh H2 with a limitation of 50 km distance from shore. In all cases, Germany has the highest technical storage potential, with a value of 9.4 PWh H2, located onshore only in salt domes in the north of the country. Moreover, Norway has 7.5 PWh H2 of storage potential for offshore caverns, which are all located in the subsurface of the North Sea Basin. • Technical H 2 storage in bedded salt deposits and salt domes across Europe. • Potential is thermodynamically derived, and respects geospatial exclusions. • Total on- and offshore European hydrogen storage potential estimated at 84.8 PWh H2. • Onshore salt caverns within 50 km of the coast constitute 7.3 PWh H2 (~30%). • Highest national storage potential is observed in Germany with 9.4 PWh H2. [ABSTRACT FROM AUTHOR]

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• Salt structures influence local geothermal gradients on structural highs. • Higher geothermal gradients occur around large faults that form fluid-flow paths. • Geothermal gradient is higher on footwalls than on the hanging-walls of large faults. • Three geothermal exploration targets are identified on the Cleaver Bank High. High-quality 3D seismic reflection data, complemented by 448 bottom-hole temperatures (BHTs) from 48 boreholes, are used to investigate the influence of salt structures and faults on the geothermal potential of the Cleaver Bank High, Southern North Sea. Developed salt structures include multiple salt diapirs, salt pillows and a salt wall, with their presence influencing local geothermal potential. Strata deposited above the Zechstein Group record geothermal gradients that are enhanced proportionally to the thickness of this salt unit. Conversely, strata buried below the Zechstein Group reveal a moderate decreasing trend in geothermal gradients as salt thickens. Large supra-salt faults can act as fluid paths to deep and hot fluid into shallow strata, resulting in the presence of high geothermal gradients in shallow strata. Importantly, geothermal gradients on the footwall of these faults are much higher than that on the corresponding hanging-wall, decreasing as one moves away from them. For example, average geothermal gradients on the footwall of the largest supra-salt fault (Fault A) are, relative to its immediate hanging-wall, 105 % higher in the North Sea Group, 26 % higher in the Chalk Group, and 41 % higher in the Rijnland, Upper and Lower Germanic Trias Groups. Additionally, sub-salt faults influence the geothermal gradient of supra-salt strata in parts of the study area where there is very thin, or even absent, salt (<100 ms; or ∼230 m), forming distinct low-amplitude trails of fluid above these same faults. They also indirectly influence geothermal gradient by controlling the position, geometry and distribution pattern of salt structures. As a corollary, three potential geothermal exploration targets are suggested on the Cleaver Bank High, one located on the footwall of a large supra-salt fault, one above thick salt, and a third target above very thin Zechstein strata where low-amplitude fluid chimneys are found. The results in this work can be applied to similar salt-bearing structural highs in Northern Europe and worldwide. [ABSTRACT FROM AUTHOR]

Potential-field-data imaging of complex geological features in deepwater salt-tectonic regions in the Gulf of Mexico remains an open active research field. There is still a lack of resolution in seismic imaging methods below and in the surroundings of allochthonous salt bodies. In this work, we present a novel three-dimensional potential-field-data simultaneous inversion method for imaging of salt features. This new approach incorporates a growth algorithm for source estimation, which progressively recovers geological structures by exploring a constrained parameter space; restrictions are posed from a priori geological knowledge of the study area. The algorithm is tested with synthetic data corresponding to a real complex salt-tectonic geological setting commonly found in exploration areas of deepwater Gulf of Mexico. Due to the huge amount of data involved in three-dimensional inversion of potential field data, the use of parallel computing techniques becomes mandatory. In this sense, to alleviate computational burden, an easy to implement parallelization strategy for the inversion scheme through OpenMP directives is presented. The methodology was applied to invert and integrate gravity, magnetic and full tensor gradient data of the study area.

The main oil and gas reserves around the world are found in regions containing evaporitic rocks. Owing to their low porosity and low permeability these rocks provide favorable conditions for hydrocarbon trapping, increasing the probability of success in oil and gas exploration. Salt rocks exhibit time-dependent strain behavior when submitted to deviatoric stresses. This behavior is described by creep constitutive laws based on deformation mechanics. One of the major challenges in modeling stress states in sedimentary basins in the presence of salt structures is to predict the magnitude of stress perturbations around salt bodies. This work presents a geo-mechanical approach to take into account the specific weight variation throughout the lithology and the effects of buoyancy in the resulting forces on the interface salt-body/formation. Modeling is driven by the fact that salt bodies cannot sustain deviatoric stresses. Numerical analyses using the Finite Element Method under plane strain conditions provide the results for the comparison of the methodologies found in the literature with the one proposed by the authors. Two synthetic models with salt dome structures are investigated. The proposed approach provided more realistic stress fields in the vicinity of salt structures. [ABSTRACT FROM AUTHOR]

Salt structures are attractive targets for hydrocarbon exploration. Salt can flow as a viscous fluid, act as hydrocarbon seal, and salt-related deformation may create reservoir traps. The high conductivity of salt can be crucial for hydrocarbon maturation in a basin. Here, we present results from the study of salt structures on the Eastern flank of Central Graben, on the Norwegian sector of the North Sea. By using our in-house basin modeling software (BMTTM), we modelled the salt structure evolution and the effects of salt on temperature and maturation. Our results show up to 85 °C cooling due to the salt heat pipe effect. An integrated impact of cooling is the depression of vitrinite Ro by up to 1.0% at the base of a large salt balloon. Our work shows that it is of critical importance to correctly identify salt volumes and to have a good geological model, and to understand the timing and geometrical evolution of salt structures. This study is, to our knowledge, the most specific analysis of the impact of salt on basin temperature and maturation published so far, and is an example of how basin modeling in the future should be an integrated part of exploration.

High-resolution remote-sensing imagery, seismic, well-log, magnetotelluric data, and field observations are integrated to investigate the Cenozoic salt-related structures in the western Kuqa depression (Quele area), southern Tianshan, NW China. Field observations of Oligocene to Miocene halokinetic sequences suggest early passive diapirism was developed in the Kuqa depression. More evidence also indicate that the progradation of the Paleogene Quele alluvial fan and basement steps have important controlling roles on the formation of the early salt structures. Rock salt was driven by the progradation wedge to flow basinward, then basement steps would provide resistance and hold the positions of early salt structures. On the basis of the kinematic model, it is suggested that the early Quele salt wall, which acts as a stress concentration zone, is deformed to the Quele salt nappe during the subsequent regional shortening, and controls the changes of along-strike geometries in the Quele area. [ABSTRACT FROM AUTHOR]

Using the seismic profiles and analog modeling, this paper addresses the salt structures in the M and B blocks in the Southern Precaspian Basin. The salt structural features, the formation mechanism and the controlling factors of structural deformation are investigated and discussed systematically. The interpretation of the seismic profiles shows that typical salt-related structures include salt wall, (flip-flop) salt diapir, salt roller, salt pillow (dome), salt weld, salt withdrawal minibasin and drag structure (or drape fold). In addition, model results demonstrate that the gravity spreading driven by progradation and aggradation is probably the primary factor in controlling the formation of the salt structures in the research area. Due to the differential loading driven by progradation, passive salt diapir developed near the progradational front followed by the formation of intrasalt withdrawal minibasin bounded by two salt diapirs, and secondary reactive triangle salt diapir or salt pillow might form within the intrasalt withdrawal minibasin. Model results also indicate that the pattern of the subsalt basement has important influence on the formation and evolution of salt structures. Salt diapirs primarily developed along the margin of the subsalt uplift basement, where high shear deformation was induced by differential sedimentary loading between the uplift area and the slope area. [ABSTRACT FROM AUTHOR]

During the past decades the effect of glacioisostatic adjustment has received much attention. However, the response of salt structures to ice-sheet loading and unloading is poorly understood. Our study aims to test conceptual models of the interaction between ice-sheet loading and salt structures by finite-element modelling. The results are discussed with regard to their implications for ice-marginal and subglacial processes. Our models consist of 2D plane-strain cross-sections, which represent simplified geological cross-sections from the Central European Basin System. The model layers represent (i) sedimentary rocks of elastoplastic rheology, (ii) a viscoelastic diapir and layer of salt and (iii) an elastoplastic basement. On top of the model, a temporarily variable pressure simulates the advance and retreat of an ice sheet. The durations of the individual loading phases were defined to resemble the durations of the Pleistocene ice advances in northern central Europe. The geometry and rheology of the model layers and the magnitude, spatial distribution and timing of ice-sheet loading were systematically varied to detect the controlling factors. All simulations indicate that salt structures respond to ice-sheet loading. An ice advance towards the diapir causes salt flow from the source layer below the ice sheet towards the diapir, resulting in an uplift of up to +4 m. The diapir continues to rise as long as the load is applied to the source layer but not to the crest of the diapir. When the diapir is transgressed by the ice sheet the diapir is pushed down (up to −36 m) as long as load is applied to the crest of the diapir. During and after ice unloading large parts of the displacement are compensated by a reversal of the salt flow. Plastic deformation of the overburden is restricted to the area immediately above the salt diapir. The displacements after unloading range between −3.1 and +2.7 m. Larger displacements are observed in models with deep-rooted diapirs, thicker ice sheets, longer duration of the loading phase, thicker salt source layers and lower viscosity of the salt. The rise or fall of diapirs triggered or amplified by ice-sheet loading are likely to affect glacigenic deformation, erosion and deposition above the diapir and within the rim synclines. Ice-load induced uplift in front of an ice sheet will provide favourable conditions for the formation of push moraines, for example by creating a topographic obstacle and inclining potential detachments. Subglacial subsidence of salt structures will enhance erosion by providing a preferential drainage pathway and fracturing of the overburden of the salt structure and thereby contribute to the incision of tunnel valleys. However, the resulting displacements are probably too low to have a marked effect on the advance or retreat pattern of the ice sheets. [ABSTRACT FROM AUTHOR]

In the framework of the German R&D programme CLEAN (CO Large-Scale Enhanced Gas Recovery in the Altmark Natural Gas Field), the geological structure of an area encompassing the Altensalzwedel sub-field and its surrounding was analysed in detail. A 3-D model was developed that contains the major geological formations and their general lithology including the natural gas reservoir (in the Permian Rotliegend), the immediate cap rock (Permian Zechstein) of the reservoir and its overburden. Based on this geological model, a 3-D steady-state thermal model was generated as part of a shared earth model. The parameterisation of the geological model layers with thermal rock properties is based on laboratory and well-log data. The model shows temperature changes in dependence of geological structure and of different rock thermal conductivity. The calculated surface heat flow is high (>80 mW m) for most of the area, which is in accordance to measured surface heat flow. Temperature on top of the Rotliegend reservoir is variable ranging from 110 to 150 °C. The quantification of temperature changes versus depth as well as laterally in the reservoir are valuable input data for modelling the dynamic processes of CO injection within CLEAN. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the interactions between the different processes that control the geothermal and fluid flow fields in sedimentary basins is crucial for exploitation of geothermal energy. Numerical models provide predictive and feasible information for a correct assessment of geothermal resources especially in areas where data acquisition is demanding. Here, we present results from numerical efforts to characterize the thermal structure and its interaction with the fluid system for the area of the North East German Basin (NEGB). The relative impact of the different (diffusive and advective) processes affecting the hydrothermal setting of the basin are investigated by means of three-dimensional numerical simulations. Lithospheric-scale numerical models are evaluated to understand the specific thermal signature of the relevant factors influencing the present-day conductive geothermal field in the NEGB. Shallow and deep structural controls on the thermal configuration of the basin are addressed and quantified. Interaction between the resulting thermal field and the active fluid system is investigated by means of three-dimensional simulations of coupled fluid flow and heat transport. Factors influencing stability and reliability of modeling predictions are discussed. The main effort is to build a physically consistent model for the basin which integrates the impacts of thermal gradients on the regional fluid regime and their coupling with the main geological units defining the basin. [ABSTRACT FROM AUTHOR]

Abstract: Using the new high-quality 3D seismic data, this paper addresses the salt structures in the KL11 area of the Laizhouwan depression in the southern offshore Bohai Bay basin. In the study area, the salt in the Sha-4 Member of the Paleogene Shahejie Formation thickened, and then formed an S–N trending salt wall, which changes shape regularly along its trend from salt diapir to salt pillow. The change in thickness of the suprasalt layers record five growth phases of the salt wall from the Eocene to the Quaternary: (1) early diapirism, (2) active diapirism, (3) passive diapirism, (4) relative structural quiescence, and (5) arching. The evolution of the salt structures was mostly governed by the multi-phase compression induced by the dextral strike-slip of the Tan–Lu fault, which formed a restraining bend in the study area. There was an original passive stock in the south, which was later tectonically squeezed by E–W compression and became a diapir. As the shortening propagated to the north from the original stock, the salt pillow was created in the north. Relative structural quiescence then followed until the next phase of compression, which arched the thick roof of the salt wall. [Copyright &y& Elsevier]

Abstract: The pre-Cretaceous basin evolution of the Feda Graben area in the vicinity of the Norwegian-Danish basin has been reconstructed utilizing geological and structural interpretation. The analysis reveals that the basin was faulted at its borders prior to the salt deposition in the Late Permian. Salt movement was initiated in Late Triassic and thick Triassic and Lower Jurassic pods were deposited in the graben area due to this movement. Salt pillows were developing along the Feda Graben bordering faults until Middle Jurassic when the pillows were collapsed. Salt diapirs within the study area preferentially occupy the crest of the Feda Graben and their occurrence is controlled by the underlying faulted topography. The diapirs were fed by salt from the central and southern parts of the basin and were developed by different processes i.e. upbuilding, downbuilding. Various raft structures were developed in the graben area hanging wall while some uplift occurred in the footwall during Mesozoic rifting. The Feda Graben area experienced rifting from Late Jurassic to Early Cretaceous. The most pronounced subsidence episode related with this rifting in the Feda Graben area took place along the eastern bounding Gert Fault. The Mesozoic rifting event is marked by a major unconformity on the seismic sections throughout the study area. Furthermore, the region experienced basin inversion in Late Cretaceous. The effects of inversion are more pronounced in the western part and along the Gert Fault. The inversion phenomenon can be properly understood only when considered together with the geometry of the Late Jurassic half-graben. Due to some inconsistencies in the previously proposed models for the development of the Feda Graben, a new conceptual model has been constructed. [Copyright &y& Elsevier]

For a normal saline lake sequence, as long as the depositional setting is the same, the sediments thickness and saline lake sequence are comparable across an area. However, in the Palaeogene Kumugeliemuqun Formation, in wells from similar depositional settings and the same member, the saline lake succession varies greatly. Member 1 of the Kumugeliemuqun Formation, depending on the combination of halite, gypsum, and dolomite (limestone), is divided into four types of saline lake successions: type A, type B, type C, and type D. In the same depositional setting, the saline lake succession and sediment thickness among adjacent areas differ. In member 2 of the Kumugeliemuqun Formation, depending on the association of mudstone and halite, ten different saline lake successions were identified as sequences 1 to 10. Even within the same depositional setting, the saline lake succession and sediment thickness can differ. To explain this phenomenon, we present evidence that includes the sediment thickness, a single cycle of saline lake succession, and an ancient landform, and a salt structure to analyze the role of tectonic deformation in members 1 and 2 of the Kumugeliemuqun Formation. Moreover, waveform indication inversion was used to describe tectonic deformation patterns. The results reveal that saline succession types C and D were the result of tectonic deformation in member 1, while saline lake succession sequence types A and B were not affected by tectonic deformation in member 1. Additionally, the ten diverse saline lake succession sequences in member 2 are all the result of intense tectonic deformation. The inversion results reveal that the inclined thrust, recumbent, and sheath folding are the principal deformation styles in member 2, while flow and hook folds are the main internal deformation styles in member 1. Finally, based on these observations, we conclude that tectonic compression created the plastic flow of rock salt, which induced folding and faulting deformation. The faults produced repetition in the lithologic succession, and the folds resulted in the inversion of the lithologic succession. Therefore, due to the effects of the faults and folds, even within the same depositional setting, the lithologic succession and sediment thicknesses differ from one another. • Features of lithological successions inside salt structures are been studied. • The deformations pattern in members 1 and 2 are been described. • Effect of salt rock deformation on kinds of lithological succession is discussed. • Fold and fault in salt structures produced kinds of lithological succession. [ABSTRACT FROM AUTHOR]

Gypsum-bearing growth strata and sedimentary racks or the Moeokopi Formation on the crest and NE flank of the Castle Valley salt wall in the Paradox Basin record salt rise, evaporite exposure, and salt-withdrawal subsidence during the Early Triassic. Detrital gypsum and dolomite clasts derived from the middle Pennsylvanian Paradox Formation were deposited in strata within a few kilometers or the salt wall and indicate that salt rise rates roughly balanced sediment accumulation, resulting in long-term exposure of mobile evaporite. Deposition took place primarily in flood-basin or inland sabkha settings that alternated between shallow subaqueous and subaerial conditions in a hyperarid climate. Matris-supported and clast-supported conglomerates with gypsum fragments represent debris-flow deposits and reworked debris-flow deposits, respectively, interbedded with flood-basin sandstone and siltstone during development of diapiric topography. Mudstone- rich flood-basin deposits with numerous stage Ito III gypsic paleosols capped by eolian gypsum sand sheets accumulated during waning salt-withdrawal subsidence. Association of detrital gypsum, eolian gypsum, and gypsic paleosols suggests that the salt wall provided a common source for gypsum in the surrounding strait This study documents a previously unrecognized salt weld with associated growth strata containing diapir-derived detritus and gypsic palesols that can be used to interpret halokinesis. [ABSTRACT FROM AUTHOR]

The Lackawanna synclinorium is a 110-km-long structural trough in the Appalachian foreland of northeastern Pennsylvania. In map view, its hinge displays a concave-to-the-foreland (i.e., concave toward the west) curve. Historically, the entire synclinorium was thought to be an Alleghanian thin-skinned contractional structure that formed similarly to the fold trains of the central Appalachian Valley and Ridge province. Interpretation of seismic reflection data across the structure, however, suggests that the synclinorium formed primarily by the removal of salt. The trend of the central and northern synclinorium reflects the location of Upper Silurian Salina salt. In the southern synclinorium, the salt-collapse structure translated northwestward over a thrust ramp joining detachments in the Cambrian Waynesboro Formation and the Salina Group. Interpretation of seismic reflection data also suggests that the basement-cover contact deepens westward and that basement-penetrating reverse faults and a Neoproterozoic rift basin are present beneath the synclinorium. We speculate that (1) partial barriers due to sedimentation and/or reef formation, and (2) localized subsidence over a Neoproterozoic rift zone may have formed a Late Silurian restricted basin that allowed thick accumulations of Salina salt. Regional-scale salt/shale flow and/or foreland-directed (i.e., westward) fluid migration during the Alleghanian orogeny might have removed as much as 700 m of salt. The removal of this salt caused the overlying strata to collapse downward and form the synclinorium. Only in the southern synclinorium was the collapse structure modified significantly by décollement tectonics. Thus, the map-view curvature of the structure reflects greater tectonic shortening and westward translation (toward the foreland) in the southern synclinorium compared to the northern synclinorium. [ABSTRACT FROM AUTHOR]

Salt structures are attractive targets for hydrocarbon exploration. Salt can flow as a viscous fluid, act as hydrocarbon seal, and salt-related deformation may create reservoir traps. The high conductivity of salt can be crucial for hydrocarbon maturation in a basin. Here, we present results from the study of salt structures on the Eastern flank of Central Graben, on the Norwegian sector of the North Sea. By using our in-house basin modeling software (BMTTM), we modelled the salt structure evolution and the effects of salt on temperature and maturation. Our results show up to 85 °C cooling due to the salt heat pipe effect. An integrated impact of cooling is the depression of vitrinite Ro by up to 1.0% at the base of a large salt balloon. Our work shows that it is of critical importance to correctly identify salt volumes and to have a good geological model, and to understand the timing and geometrical evolution of salt structures. This study is, to our knowledge, the most specific analysis of the impact of salt on basin temperature and maturation published so far, and is an example of how basin modeling in the future should be an integrated part of exploration. [ABSTRACT FROM AUTHOR]