Articles | Volume 12, issue 1
Solid Earth, 12, 35–58, 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue: Faults, fractures, and fluid flow in the shallow crust
Research article 13 Jan 2021
Research article | 13 Jan 2021
Characterization of discontinuities in potential reservoir rocks for geothermal applications in the Rhine-Ruhr metropolitan area (Germany)
Martin Balcewicz et al.
No articles found.
Mathias Nehler, Ferdinand Stoeckhert, Anne Oelker, Jörg Renner, and Erik Saenger
Solid Earth Discuss.,
Publication in SE not foreseenShort summary
The technique of X-ray computed tomography (CT) is widely used in multiple disciplines such as medicine, industry and earth sciences. However, quantitative analysis from the reconstructed images are subject to errors due to technical limitations and subsequent evaluation workflows. The paper addresses the uncertainties related to the estimation of porosity from these images and compares the results with laboratory measurements. Accurate porosity estimates are linked to sufficient resolution.
Claudia Werner and Erik H. Saenger
Solid Earth, 9, 1487–1505,Short summary
Time reverse imaging is a method for locating quasi-simultaneous or low-amplitude earthquakes. Numerous three-dimensional synthetic simulations were performed to discover the influence of station distributions, complex velocity models and high noise rates on the reliability of localisations. The guidelines obtained enable the estimation of the localisation success rates of an existing station set-up and provide the basis for designing new arrays.
Kathleen Sell, Beatriz Quintal, Michael Kersten, and Erik H. Saenger
Solid Earth, 9, 699–711,Short summary
Sediments containing hydrates dispersed in the pore space show a characteristic seismic anomaly: a high attenuation along with increasing seismic velocities. Recent major findings from synchrotron experiments revealed the systematic presence of thin water films between quartz and gas hydrate. Our numerical studies support earlier speculation that squirt flow causes high attenuation at seismic frequencies but are based on a conceptual model different to those previously considered.
Kathleen Sell, Erik H. Saenger, Andrzej Falenty, Marwen Chaouachi, David Haberthür, Frieder Enzmann, Werner F. Kuhs, and Michael Kersten
Solid Earth, 7, 1243–1258,
Related subject area
Subject area: Tectonic plate interactions, magma genesis, and lithosphere deformation at all scales | Editorial team: Structural geology and tectonics, rock physics, experimental deformation | Discipline: Structural geologyAnalysis of deformation bands associated with the Trachyte Mesa intrusion, Henry Mountains, Utah: implications for reservoir connectivity and fluid flow around sill intrusionsOn a new robust workflow for the statistical and spatial analysis of fracture data collected with scanlines (or the importance of stationarity)Micro- and nano-porosity of the active Alpine Fault zone, New ZealandUnraveling the origins and P-T-t evolution of the allochthonous Sobrado unit (Órdenes Complex, NW Spain) using combined U–Pb titanite, monazite and zircon geochronology and rare-earth element (REE) geochemistryFracture attribute scaling and connectivity in the Devonian Orcadian Basin with implications for geologically equivalent sub-surface fractured reservoirsStructural control on fluid flow and shallow diagenesis: insights from calcite cementation along deformation bands in porous sandstonesThe growth of faults and fracture networks in a mechanically evolving, mechanically stratified rock mass: a case study from Spireslack Surface Coal Mine, ScotlandRelationship between microstructures and resistance in mafic assemblages that deform and transformMultiphase, decoupled faulting in the southern German Molasse Basin – evidence from 3-D seismic dataNear-surface Palaeocene fluid flow, mineralisation and faulting at Flamborough Head, UK: new field observations and U–Pb calcite dating constraintsGeologic characterization of nonconformities using outcrop and core analogs: hydrologic implications for injection-induced seismicityMapping the fracture network in the Lilstock pavement, Bristol Channel, UK: manual versus automaticPrecambrian faulting episodes and insights into the tectonothermal history of north Australia: microstructural evidence and K–Ar, 40Ar–39Ar, and Rb–Sr dating of syntectonic illite from the intracratonic Millungera BasinExtensional reactivation of the Penninic Frontal Thrust 3 Ma ago as evidenced by U-Pb dating on calcite in fault zone cataclasiteTransverse jointing in foreland fold-and-thrust belts: a remote sensing analysis in the eastern PyreneesThe Piuquencillo Fault System: a long-lived, Andean-transverse fault system and its relationship with magmatic and hydrothermal activityExperimental evidence that viscous shear zones generate periodic pore sheets that focus mass transportEmplacement ofPre-inversion normal fault geometry controls inversion style and magnitude, Farsund Basin, offshore southern NorwayUncertainty assessment for 3D geologic modeling of fault zones based on geologic inputs and prior knowledgeControl of pre-existing fabric in fracture formation, reactivation and vein emplacement under variable fluid pressure conditions: an example from Archean greenstone belt, IndiaExtension and inversion of salt-bearing rift systemsStructure and kinematics of an extensional growth fold, Hadahid Fault System, Suez Rift, EgyptThrow variations and strain partitioning associated with fault-bend folding along normal faultsDistribution, microphysical properties, and tectonic control of deformation bands in the Miocene accretionary prism (Whakataki Formation) of the Hikurangi subduction zoneResolved stress analysis, failure mode, and fault-controlled fluid conduitsAn active tectonic field for CO2 storage management: the Hontomín onshore case study (Spain)Evolution of structures and hydrothermal alteration in a Palaeoproterozoic supracrustal belt: Constraining paired deformation–fluid flow events in an Fe and Cu–Au prospective terrain in northern SwedenEstimating the depth and evolution of intrusions at resurgent calderas: Los Humeros (Mexico)Abutting faults: a case study of the evolution of strain at Courthouse branch point, Moab Fault, UtahFluid-mediated, brittle–ductile deformation at seismogenic depth – Part 2: Stress history and fluid pressure variations in a shear zone in a nuclear waste repository (Olkiluoto Island, Finland)Influence of inherited structural domains and their particular strain distributions on the Roer Valley Graben evolution from inversion to extensionFault zone architecture of a large plate-bounding strike-slip fault: a case study from the Alpine Fault, New ZealandAn automated fracture trace detection technique using the complex shearlet transformA numerical sensitivity study of how permeability, porosity, geological structure, and hydraulic gradient control the lifetime of a geothermal reservoirActors, actions, and uncertainties: optimizing decision-making based on 3-D structural geological modelsStructure of massively dilatant faults in Iceland: lessons learned from high-resolution unmanned aerial vehicle dataFracturing and crystal plastic behaviour of garnet under seismic stress in the dry lower continental crust (Musgrave Ranges, Central Australia)How can geologic decision-making under uncertainty be improved?Overprinting translational domains in passive margin salt basins: insights from analogue modellingFault slip envelope: a new parametric investigation tool for fault slip based on geomechanics and 3-D fault geometry2-D finite displacements and strain from particle imaging velocimetry (PIV) analysis of tectonic analogue models with TecPIVQuantification of uncertainty in 3-D seismic interpretation: implications for deterministic and stochastic geomodeling and machine learningThe internal structure and composition of a plate-boundary-scale serpentinite shear zone: the Livingstone Fault, New ZealandFluid-mediated, brittle–ductile deformation at seismogenic depth – Part 1: Fluid record and deformation history of fault veins in a nuclear waste repository (Olkiluoto Island, Finland)A new methodology to train fracture network simulation using multiple-point statisticsHow do we see fractures? Quantifying subjective bias in fracture data collectionLinked thick- to thin-skinned inversion in the central Kirthar Fold Belt of PakistanComment on “Channel flow, tectonic overpressure, and exhumation of high-pressure rocks in the Greater Himalayas” by Marques et al. (2018)Tectono-thermal evolution of Oman's Mesozoic passive continental margin under the obducting Semail Ophiolite: a case study of Jebel Akhdar, Oman
Penelope I. R. Wilson, Robert W. Wilson, David J. Sanderson, Ian Jarvis, and Kenneth J. W. McCaffrey
Solid Earth, 12, 95–117,Short summary
Magma accommodation in the shallow crust leads to deformation of the surrounding host rock through the creation of faults, fractures and folds. This deformation will impact fluid flow around intrusive magma bodies (including sills and laccoliths) by changing the porosity and permeability network of the host rock. The results may have important implications for industries where fluid flow within the subsurface adds value (e.g. oil and gas, hydrology, geothermal and carbon sequestration).
Andrea Bistacchi, Silvia Mittempergher, Mattia Martinelli, and Fabrizio Storti
Solid Earth, 11, 2535–2547,Short summary
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.
Martina Kirilova, Virginia Toy, Katrina Sauer, François Renard, Klaus Gessner, Richard Wirth, Xianghui Xiao, and Risa Matsumura
Solid Earth, 11, 2425–2438,Short summary
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.
José Manuel Benítez-Pérez, Pedro Castiñeiras, Juan Gómez-Barreiro, José R. Martínez Catalán, Andrew Kylander-Clark, and Robert Holdsworth
Solid Earth, 11, 2303–2325,Short summary
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.
Anna M. Dichiarante, Ken J. W. McCaffrey, Robert E. Holdsworth, Tore I. Bjørnarå, and Edward D. Dempsey
Solid Earth, 11, 2221–2244,Short summary
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.
Leonardo Del Sole, Marco Antonellini, Roger Soliva, Gregory Ballas, Fabrizio Balsamo, and Giulio Viola
Solid Earth, 11, 2169–2195,Short summary
This study focuses on the impact of deformation bands on fluid flow and diagenesis in porous sandstones in two different case studies (northern Apennines, Italy; Provence, France) by combining a variety of multiscalar mapping techniques, detailed field and microstructural observations, and stable isotope analysis. We show that deformation bands buffer and compartmentalize fluid flow and foster and localize diagenesis, recorded by carbonate cement nodules spatially associated with the bands.
Billy James Andrews, Zoe Kai Shipton, Richard Lord, and Lucy McKay
Solid Earth, 11, 2119–2140,Short summary
Through geological mapping we find that fault zone internal structure depends on whether or not the fault cuts multiple lithologies, the presence of shale layers, and the orientation of joints and coal cleats at the time of faulting. During faulting, cementation of fractures (i.e. vein formation) is highest where the fractures are most connected. This leads to the counter-intuitive result that the highest-fracture-density part of the network often has the lowest open-fracture connectivity.
Nicolas Mansard, Holger Stünitz, Hugues Raimbourg, Jacques Précigout, Alexis Plunder, and Lucille Nègre
Solid Earth, 11, 2141–2167,Short summary
Our rock deformation experiments (solid-medium Griggs-type apparatus) on wet assemblages of mafic compositions show that the ability of minerals to react controls the portions of rocks that deform and that minor chemical and mineralogical variations can considerably modify the strength of deformed assemblages. Our study suggests that the rheology of mafic rocks, which constitute a large part of the oceanic crust, cannot be summarized as being rheologically controlled by monophase materials.
Vladimir Shipilin, David C. Tanner, Hartwig von Hartmann, and Inga Moeck
Solid Earth, 11, 2097–2117,Short summary
In our work, we carry out an in-depth structural analysis of a geometrically decoupled fault system in the southern German Molasse Basin using a high-resolution 3-D seismic dataset. Based on this analysis, we reconstruct the tectonic history and changes in the stress regimes to explain the structure and evolution of faults. The results contribute in understanding the driving mechanisms behind formation, propagation, and reactivation of faults during foreland basin formation.
Nick M. W. Roberts, Jack K. Lee, Robert E. Holdsworth, Christopher Jeans, Andrew R. Farrant, and Richard Haslam
Solid Earth, 11, 1931–1945,Short summary
We characterise a well-known fractured and faulted exposure of Cretaceous chalk in NE England, combining field observations with novel U–Pb calcite dating. We show that the faulting and associated fluid flow occurred during the interval of ca. 64–56 Ma, predating earlier estimates of Alpine-related tectonic inversion. We demonstrate that the main extensional fault zone acted as a conduit linking voluminous fluid flow and linking deeper sedimentary layers with the shallow subsurface.
Elizabeth S. Petrie, Kelly K. Bradbury, Laura Cuccio, Kayla Smith, James P. Evans, John P. Ortiz, Kellie Kerner, Mark Person, and Peter Mozley
Solid Earth, 11, 1803–1821,Short summary
A summary of observed rock properties across the contact between crystalline basement rock and the overlying younger sedimentary rocks from outcrop and core samples is presented. The data span a range of tectonic settings and describe the rock types immediately adjacent to the contact. The range of features observed at these contacts can influence the migration of fluids. The observations presented here are critical for the safe implementation of fluid injection and geothermal production.
Christopher Weismüller, Rahul Prabhakaran, Martijn Passchier, Janos L. Urai, Giovanni Bertotti, and Klaus Reicherter
Solid Earth, 11, 1773–1802,Short summary
We photographed a fractured limestone pavement with a drone to compare manual and automatic fracture tracing and analyze the evolution and spatial variation of the fracture network in high resolution. We show that automated tools can produce results comparable to manual tracing in shorter time but do not yet allow the interpretation of fracture generations. This work pioneers the automatic fracture mapping of a complete outcrop in detail, and the results can be used as fracture benchmark.
I. Tonguç Uysal, Claudio Delle Piane, Andrew James Todd, and Horst Zwingmann
Solid Earth, 11, 1653–1679,Short summary
This study represents an integrated approach to radiometric age dating using potassium-bearing clay minerals formed during faulting and provides insights into the enigmatic time–space distribution of Precambrian tectonic zones in north-central Australia. Specifically, our work firmly indicates a late Mesoproterzoic minimum age for the Millungera Basin in north Australia and a previously unrecorded concealed late Mesoproterozoic–early Neoproterozoic tectonic event in north-central Australia.
Antonin Bilau, Yann Rolland, Stéphane Schwartz, Nicolas Godeau, Abel Guihou, Pierre Deschamps, Benjamin Brigaud, Aurélie Noret, Thierry Dumont, and Cécile Gautheron
Solid Earth Discuss.,
Revised manuscript accepted for SEShort summary
As a result of the collision between the European and Apulian plates, the Alps have experienced several evolutionary stages. The Penninic Frontal Thrust (PFT) (major thrust) was associated to compression and now seismic studies show ongoing extensional activity. Calcite mineralisations associated to extension and compresionnal strucures were sampled. Last deformation stage is dated by U-Pb at 4.9–2.3 Ma and isotopes analysis evidence deep crustal fluid's mobilisation.
Stefano Tavani, Pablo Granado, Amerigo Corradetti, Thomas Seers, Josep Maria Casas, and Josep Anton Muñoz
Solid Earth, 11, 1643–1651,Short summary
Using orthophotos, we manually digitized 30 000 joints in the eastern Ebro Basin of the Pyrenees. Joints are perpendicular to the belt in the frontal portion of the belt and in the inner and central portion of the foredeep basin. Joint orientations in the external portion of the foredeep become less clustered. Joints in the studied area formed in the foredeep in response to foredeep-parallel stretching, which becomes progressively less intense within the external portion of the foredeep basin.
Jose Piquer, Orlando Rivera, Gonzalo Yañez, and Nicolas Oyarzun
Solid Earth Discuss.,
Revised manuscript accepted for SEShort summary
A proper recognition of deep, long-lived fault systems is very important for society. They can produce potentially dangerous earthquakes. They can also act as pathways for magmas and hydrothermal fluids, leading to the formation of volcanoes, geothermal systems and mineral deposits. However, the manifestations of these very old faults in the present-day surface can be very subtle. Here we present a detailed, multi-disciplinary study of a fault system of this type in the Andes of central Chile.
James Gilgannon, Marius Waldvogel, Thomas Poulet, Florian Fusseis, Alfons Berger, Auke Barnhoorn, and Marco Herwegh
Solid Earth Discuss.,
Revised manuscript accepted for SEShort summary
Using experiments that simulate deep tectonic interfaces, known as viscous shear zones, we found that these zones spontaneously develop periodic sheets of small pores. The presence of porous layers in deep rocks undergoing tectonic deformation is significant because requires a change to the current model of how the Earth deforms. Emergent porous layers in viscous rocks will focus mineralising fluids and could lead to the seismic failure of rocks that are supposed to never have this occur.
exoticZechstein slivers along the inverted Sontra Graben (northern Hessen, Germany): clues from balanced crosssections and geometrical forward modelling
Jakob Bolz and Jonas Kley
Solid Earth Discuss.,
Revised manuscript under review for SEShort summary
To assess the role smaller graben structures near the southern edge of the Central European Basin System play for the basin’s overall deformational history, we take advantage of a feature found on some of these structures, where slivers from older rock units appear along the graben's main fault, surrounded on both sides by younger strata. The implications for the geometry of the fault provide a substantially improved estimate for the magnitude of normal and thrust motion along the fault system.
Thomas B. Phillips, Christopher A.-L. Jackson, and James R. Norcliffe
Solid Earth, 11, 1489–1510,Short summary
Normal faults often reactivate under compression, in a process called inversion. The 3D geometry of these structures (and the effect on resultant inversion structural style) is often not considered. Using seismic reflection data, we examine how stresses form different inversion styles that are controlled by the geometry of the pre-existing structure. Geometrically simple faults are preferentially reactivated; more complex areas are typically not reactivated and instead experience bulk uplift.
Ashton Krajnovich, Wendy Zhou, and Marte Gutierrez
Solid Earth, 11, 1457–1474,Short summary
In this paper, a novel methodology of 3D geologic model uncertainty assessment that considers both input data and prior knowledge is developed and applied to characterize fault zones – areas of damaged rock surrounding a fault surface that are important to subsurface engineering projects. The results of the study demonstrate how existing frameworks can be expanded to incorporate new types of information to arrive at a realistic and straightforward model of fault zone geometry in the subsurface.
Sreyashi Bhowmick and Tridib Kumar Mondal
Solid Earth, 11, 1227–1246,Short summary
We explore pre-existing fabric in metabasalts replete with a wide range of crisscross fractures/faults, hosting quartz veins of variable orientations and thicknesses in the Chitradurga region, India. The fractures are identified as components of a riedel shear system. We evaluate reactivation potential of fractures and conclude that episodic changes in fluid pressure conditions triggered fault-valve action, thereby reactivating fabric and fractures, leading to vein emplacement in the region.
Tim P. Dooley and Michael R. Hudec
Solid Earth, 11, 1187–1204,Short summary
Sandbox models investigated extension and inversion of salt-bearing rifts such as those found in the Moroccan High Atlas, North Africa. Sand packs were stretched and the structural lows were filled with a salt analog. Models were then subjected to additional extension and loading that remobilized the salt into diapirs. During shortening the distribution of the salt in the overburden governed the structural styles and trends in the supra-salt strata, strongly decoupled from subsalt deformation.
Christopher A.-L. Jackson, Paul S. Whipp, Robert L. Gawthorpe, and Matthew M. Lewis
Solid Earth, 11, 1027–1051,Short summary
Plate tectonics describes the creation, motion, and ultimate destruction of the Earth's continents and oceans. A key plate tectonic process is continental extension; this occurs when the Earth's plates are pulled apart to ultimately form a new ocean. Giant fractures (faults) accommodate plate stretching, although buckling (folding) is thought to be locally important. We use field data to understand how fracturing and buckling relate to each other, demonstrating they are spatially complex.
Efstratios Delogkos, Muhammad Mudasar Saqab, John J. Walsh, Vincent Roche, and Conrad Childs
Solid Earth, 11, 935–945,Short summary
Normal faults have irregular geometries on a range of scales. A quantitative model has been presented which illustrates the range of deformation arising from movement on fault surface irregularities, with fault-bend folding generating geometries reminiscent of normal drag and reverse drag. We show that fault throw can be subject to errors of up to ca. 50 % for realistic fault bend geometries (up to ca. 40°), even on otherwise sub-planar faults with constant displacement.
Kathryn E. Elphick, Craig R. Sloss, Klaus Regenauer-Lieb, and Christoph E. Schrank
Solid Earth Discuss.,
Revised manuscript accepted for SEShort summary
We analysed a sedimentary rock package located in Castlepoint, New Zealand, to test the control of the tectonic setting on the observed deformation structures. In extension and contraction, we observed faults and small fault-like structures characterised by complex spatial patterns and a reduction in porosity and grain size compared to the host rock. With these properties, the structures are likely to act as barriers to fluid flow and cause compartmentalisation of the sedimentary sequence.
David A. Ferrill, Kevin J. Smart, and Alan P. Morris
Solid Earth, 11, 899–908,Short summary
This paper explores failure modes and deformation behavior of faults in the mechanically layered Eagle Ford Formation, an ultra-low permeability self-sourced oil and gas reservoir and aquitard in southwest Texas, USA. The role of dilation versus slip relates in predictable ways to mechanical stratigraphy, stress field, and dilation and slip tendency. We conclude that dilation tendency vs. slip tendency can be used to infer fault and fracture deformation modes and conduit versus seal behaviour.
Raúl Pérez-López, José F. Mediato, Miguel A. Rodríguez-Pascua, Jorge L. Giner-Robles, Adrià Ramos, Silvia Martín-Velázquez, Roberto Martínez-Orío, and Paula Fernández-Canteli
Solid Earth, 11, 719–739,Short summary
Long-term monitoring of CO2 of onshore storage has to consider thousands of years as a medium lifetime of the storage. In this wide time interval, the stress and strain properties of the reservoir change and earthquakes could occur. Therefore, we have to identify those fault sets which can be reactivated by changing the stress conditions. We need to know the role of active fault sets and model the changing conditions to prevent induced seismicity.
Joel B. H. Andersson, Tobias E. Bauer, and Edward P. Lynch
Solid Earth, 11, 547–578,Short summary
In this field-based study, geological structures and hydrothermal alterations in one of the least known geological terrains in Sweden are investigated. The area is located above the polar circle in northwestern Sweden that produces a significant portion of the iron and copper in the EU. A new tectonic model based on field evidence and microstructures is presented and it is shown that minerals typical for iron and copper–gold deposits can be linked to different phases of the structural evolution.
Stefano Urbani, Guido Giordano, Federico Lucci, Federico Rossetti, Valerio Acocella, and Gerardo Carrasco-Núñez
Solid Earth, 11, 527–545,Short summary
In Los Humeros, through field structural–geological mapping and analogue experiments, we show a discontinuous and small-scale (areal size ~ 1 km2) uplift of the caldera floor due to the emplacement of multiple shallow (< 1 km) magmatic bodies. These results allow for a better assessment of the subsurface structure of Los Humeros, with crucial implications for planning future geothermal exploration, which should account for the local geothermal gradient affected by such a shallow heat source.
Heijn van Gent and Janos L. Urai
Solid Earth, 11, 513–526,Short summary
Faults form due to stresses caused by crustal processes. As faults influence the stress field locally, fault interaction leads to local variations in the stress field, but this is difficult to observe directly. We describe an outcrop of one fault abuting into another one. By careful measurement of structures in the overlapping deformation zones and separating them using published relative age data, we show a rotation in the local stress field resulting from the faults growing to each other
Francesca Prando, Luca Menegon, Mark Anderson, Barbara Marchesini, Jussi Mattila, and Giulio Viola
Solid Earth, 11, 489–511,
Jef Deckers, Bernd Rombaut, Koen Van Noten, and Kris Vanneste
Solid Earth Discuss.,
Revised manuscript accepted for SEShort summary
This study shows the presence of two structural domains in the western border fault system of the Roer Valley Graben. These domains, dominated by NW-SE striking faults, displayed distinctly different strain distributions during both Late Cretaceous compression and Cenozoic extension. The southern domain is characterized by narrow, localized faulting, while the northern domain is characterized by wide, distributed faulting. The non-colinear WNW-ESE Grote Brogel fault links both domains.
Bernhard Schuck, Anja M. Schleicher, Christoph Janssen, Virginia G. Toy, and Georg Dresen
Solid Earth, 11, 95–124,
Rahul Prabhakaran, Pierre-Olivier Bruna, Giovanni Bertotti, and David Smeulders
Solid Earth, 10, 2137–2166,Short summary
This contribution describes a technique to automatically extract digitized fracture patterns from images of fractured rock. Digitizing fracture patterns, accurately and rapidly with minimal human intervention, is a desirable objective in fractured rock characterization. Our method can extract fractures at varying scales of rock discontinuities, and results are presented from three different outcrop settings. The method enables faster processing of copious amounts of fractured outcrop image data.
Johanna F. Bauer, Michael Krumbholz, Elco Luijendijk, and David C. Tanner
Solid Earth, 10, 2115–2135,Short summary
We use a 4-D numerical sensitivity study to investigate which geological parameters exert a dominant control on the quality of a deep geothermal reservoir. We constrain how the variability of these parameters affects the economic potential of a reservoir. We show that the interplay of high permeability and hydraulic gradient is the dominant control on reservoir lifetime. Fracture anisotropy, typical for faults, leads to fluid channelling and thus restricts the exploitable volume significantly.
Fabian Antonio Stamm, Miguel de la Varga, and Florian Wellmann
Solid Earth, 10, 2015–2043,
Christopher Weismüller, Janos L. Urai, Michael Kettermann, Christoph von Hagke, and Klaus Reicherter
Solid Earth, 10, 1757–1784,Short summary
We use drones to study surface geometries of massively dilatant faults (MDFs) in Iceland, with apertures up to tens of meters at the surface. Based on throw, aperture and structures, we define three geometrically different endmembers of the surface expression of MDFs and show that they belong to one continuum. The transition between the endmembers is fluent and can change at one fault over short distances, implying less distinct control of deeper structures on surface geometries than expected.
Friedrich Hawemann, Neil Mancktelow, Sebastian Wex, Giorgio Pennacchioni, and Alfredo Camacho
Solid Earth, 10, 1635–1649,
Cristina G. Wilson, Clare E. Bond, and Thomas F. Shipley
Solid Earth, 10, 1469–1488,Short summary
In this paper, we outline the key insights from decision-making research about how, when faced with uncertainty, humans constrain decisions through the use of heuristics (rules of thumb), making them vulnerable to systematic and suboptimal decision biases. We also review existing strategies to debias decision-making that have applicability in the geosciences, giving special attention to strategies that make use of information technology and artificial intelligence.
Zhiyuan Ge, Matthias Rosenau, Michael Warsitzka, and Rob L. Gawthorpe
Solid Earth, 10, 1283–1300,Short summary
Salt basins are important as they bear abundant natural resources and record valuable geological information. However, some models of salt basin evolution do not fully reconcile with natural examples. Using state-of-the-art analogue modelling, we investigate how a relatively stable area, the translational domain, occurs and gets overprinted in salt basins. The results suggest that that variation of sediment deposition is the key factor for overprinting the translational domain.
Roger Soliva, Frantz Maerten, Laurent Maerten, and Jussi Mattila
Solid Earth, 10, 1141–1154,Short summary
We propose innovative parametric modeling allowing for analysis of a very large number of fault-slip numerical simulations on 3-D discrete fault network. The approach allows for the first time producing failure envelopes of large rock volumes containing faults, using variations of geological conditions such as remote stresses, cohesion, friction, and fluid pressure. This tool helps to define the most conservative fault slip hazard case or to account for potential uncertainties in the input data.
David Boutelier, Christoph Schrank, and Klaus Regenauer-Lieb
Solid Earth, 10, 1123–1139,Short summary
Image correlation techniques have provided new ways to analyse the distribution in space and time of deformation in analogue models of tectonics. Here, we demonstrate how the correlation of successive time-lapse images of a deforming model allows calculating the finite displacements and finite strain tensor. We illustrate, using synthetic images, the ability of the algorithm to produce maps of the finite deformation.
Alexander Schaaf and Clare E. Bond
Solid Earth, 10, 1049–1061,Short summary
Seismic reflection data allow us to infer subsurface structures such as horizon and fault surfaces. The interpretation of this indirect data source is inherently uncertainty, and our work takes a first look at the scope of uncertainties involved in the interpretation of 3-D seismic data. We show how uncertainties of fault interpretations can be related to data quality and discuss the implications for the 3-D modeling of subsurface structures derived from 3-D seismic data.
Matthew S. Tarling, Steven A. F. Smith, James M. Scott, Jeremy S. Rooney, Cecilia Viti, and Keith C. Gordon
Solid Earth, 10, 1025–1047,Short summary
Shear zones dominated by hydrated mantle rocks (serpentinites) occur in many tectonic settings around the world. To better understand the internal structure, composition and possible mechanical behaviour of these shear zones, we performed a detailed field, petrological and microanalytical study of the Livingstone Fault in New Zealand. We propose a conceptual model to account for the main physical and chemical processes that control deformation in large serpentinite shear zones.
Barbara Marchesini, Paolo Stefano Garofalo, Luca Menegon, Jussi Mattila, and Giulio Viola
Solid Earth, 10, 809–838,Short summary
We documented the role of fluids in the initial embrittlement of the Svecofennian basement and subsequent strain localization and fault evolution at the brittle–ductile transition zone. We studied the fault rocks of a deeply exhumed fault system characterized by mixed brittle–ductile deformation. Results from fluid inclusions, mineral chemistry, and geothermometry of synkinematic minerals document the ingress of distinct fluid batches and fluid pressure oscillations.
Pierre-Olivier Bruna, Julien Straubhaar, Rahul Prabhakaran, Giovanni Bertotti, Kevin Bisdom, Grégoire Mariethoz, and Marco Meda
Solid Earth, 10, 537–559,Short summary
Natural fractures influence fluid flow in subsurface reservoirs. Our research presents a new methodology to predict the arrangement of these fractures in rocks. Contrary to the commonly used statistical models, our approach integrates more geology into the simulation process. The method is simply based on the drawing of images, can be applied to any type of rocks in various geological contexts, and is suited for fracture network prediction in water, geothermal, or hydrocarbon reservoirs.
Billy J. Andrews, Jennifer J. Roberts, Zoe K. Shipton, Sabina Bigi, M. Chiara Tartarello, and Gareth Johnson
Solid Earth, 10, 487–516,Short summary
Rocks often contain fracture networks, which can strongly affect subsurface fluid flow and the strength of a rock mass. Through fieldwork and workshops we show that people report a different number of fractures from the same sample area of a fracture network. This variability results in significant differences in derived fracture statistics, which are often used as inputs for geological models. We suggest protocols to recognise, understand, and limit this effect on fracture data collection.
Ralph Hinsch, Chloé Asmar, Muhammad Nasim, Muhammad Asif Abbas, and Shaista Sultan
Solid Earth, 10, 425–446,Short summary
We use surface and geophysical subsurface data to constrain the structure and evolution of the central Kirthar Fold Belt, a mountain belt on the western margin of the Indian Plate in Pakistan. It can be shown that the extension phase prior to the collision of India with Asia has a major impact on how the rocks deform today. The inherited structures in the crystalline basement reactivate in an opposite sense and complexly deform the sedimentary rocks that have deposited before collision.
John P. Platt
Solid Earth, 10, 357–361,Short summary
The channel flow model proposed by Marques et al (2018) for the Himalayas has a geometry that would not generate any excess pressure. The excess pressure calculated by the authors, based on a different and highly improbable geometry, is so high that the overlying rocks would not be able to contain it: they would bend or break in such a way as to relieve the pressure. The conclusions drawn by the authors are therefore unwarranted and misleading.
Arne Grobe, Christoph von Hagke, Ralf Littke, István Dunkl, Franziska Wübbeler, Philippe Muchez, and Janos L. Urai
Solid Earth, 10, 149–175,Short summary
The Mesozoic sequences of the Oman mountains experienced only weak post-obduction overprint and deformation, and thus they offer a unique natural laboratory to study obduction. We present a study of pressure and temperature evolution in the passive continental margin under the Oman Ophiolite using numerical basin models calibrated with thermal maturity data, fluid-inclusion thermometry, and low-temperature thermochronology.
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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.
The geothermal potential of a carbonate reservoir in the Rhine-Ruhr area, Germany, was...