Carlo Dietl | Gesteinslabor dr. Eberhard Jahns (original) (raw)

Papers by Carlo Dietl

Safety of nuclear waste disposal, Sep 5, 2023

This paper presents a road map for providing training to experienced geoscientists, engineers, an... more This paper presents a road map for providing training to experienced geoscientists, engineers, and data scientists who seek to participate in geothermal energy exploration, development, and integration. The road map starts by identifying the foundational skills and knowledge base of experienced geoscientists and engineers, and then specifically discusses which elements are of direct value in geothermal energy development. The paper then discusses the best strategies for upscaling skills and closing knowledge gaps, as well as pathways for immediate implementation of the knowledge in the form of planning documents and projects. The final stage of the road map includes assessment and designing collaborative challenges so that teams learn how best to work together and achieve their goals. The final section of the paper includes brief case studies of two examples of retooled geothermal education offered by the American Association of Petroleum Geologists (AAPG).

In this study, interaction between fluids and deformation during the final stages of magma-poor r... more In this study, interaction between fluids and deformation during the final stages of magma-poor rifting was investigated. The Tasna Ocean-Continent transition, located in the Swiss Alps, was studied and a large data set was obtained from profiles oriented perpendicular to two detachment faults. One of these juxtaposed serpentinized mantle against continental crust and the other exhumed both mantle and continental crust to the seafloor. Deformation associated with detachment faulting showed many common features but also some phenomena which were unique to each fault, confirming their sequential activity and differing roles in the exhumation process. Oxygen isotopes indicated the presence of both pervasive and channeled fluid phases, either accompanying or post-dating serpentinization. Deformation in the fault zone occurred in previously serpentinized mantle indicating that serpentinization pre-dated final exhumation. Most strain localization and displacement occurred in fault cores which are narrow zones beneath the detachments. These are underlain by wide zones characterized by more distributed strain. Transitional fabrics as well as reactivated and/or overprinted deformation structures indicated that the final phase of rifting is complex. Fault cores acted as fluid conduits or barriers. Thus, the most deformed zones may become the least permeable. Hence the coupling between deformation and fluid flow is complex in a study area subjected to several phases of deformation and fluid flow. Finally the importance of serpentinization in the evolution of magma-poor rifting was investigated. It was found that serpentinization is the consequence rather than the reason for strain localization at magma-poor margins. However, serpentinization may be an important process which can accelerate exhumation rates in the very latest stages of magma-poor rifting. The pre-existing deformation history of the crust may also be of importance for the development and location of margins.

Mineralogy and Petrology, Jun 12, 2001

The three major units of the Bergstra Èsser Odenwald (Frankenstein Complex, Flasergranitoid Zone ... more The three major units of the Bergstra Èsser Odenwald (Frankenstein Complex, Flasergranitoid Zone and southern Bergstra Èsser Odenwald) are, according to literature, separated by two major shear zones. The aim of the present paper is to evaluate the importance of these sutures by comparing new hornblende geothermobarometry data from ®ve plutons of the Flasergranitoid Zone with published P-T data from the entire Bergstra Èsser Odenwald. Furthermore radiometric, geochemical and structural data from the literature were also used for this purpose. Temperatures were calculated with the amphibole-plagioclase thermometer and range from 600 to 800 C. Determinations of the intrusion depth, using the Al-in-hornblende barometer show that most plutons intruded at pressures ranging from about 4 to 6 kbar (13 to 20 km). These combined data do not allow to postulate a major suture zone between the Flasergranitoid Zone and the southern Bergstra Èsser Odenwald, while comparison of similar data from the Flasergranitoid Zone and the Frankenstein Complex verify the importance of this shear zone. Moreover, our P-T data show that the high temperature ± low pressure metamorphism in the Bergstra Èsser Odenwald can also be interpreted as contact metamorphism and not necessarily as regional metamorphism. Zusammenfassung Hornblende-Thermobarometrie an Granitoiden des Mittleren Odenwaldes (Deutschland) und ihre Implikation fu Èr die geotektonische Entwicklung des Odenwaldes Die drei Haupteinheiten des Bergstra Èsser Odenwaldes (Frankenstein-Komplex, Flasergranitoid-Zone und su Èdlicher Bergstra Èsser Odenwald) werden nach der Literatur durch zwei bedeutende Scherzonen voneinander getrennt. Ziel der vorliegenden Arbeit ist es, die wirkliche Bedeutung dieser beiden Suturen herauszuarbeiten. Dazu wurden eigene, neue Hornblende-Geothermobarometrie-Daten, die an fu Ènf Plutonen der Flasergranitoidzone ermittelt wurden, mit bereits publizierten P-T-Daten aus dem gesamten Bergstra Èsser Odenwald verglichen. Zudem wurden radiometrische, geochemische und strukturgeologische Datensa Ètze aus der Literatur fu Èr diesen Zweck benutzt. Kristallisationstemperaturen wurden mit Hilfe des Amphibol-Plagioklas-Thermometers errechnet und liegen zwischen 600 und 800 C. Die Bestimmung der Intrusionstiefe mit dem Al-in-Hornblende-Barometer ergab fu Èr die meisten Plutone Dru Ècke im Bereich von 4± 6 kbar (13±20 km). Diese, sowie radiometrische, geochemische und strukturgeologische Daten aus der Flasergranitoid-zone und dem su Èdlichen Bergstra Èsser Odenwald geben keinen Hinweis auf eine wichtige Suturzone zwischen diesen beiden geotektonischen Einheiten, wohingegen der Vergleich a Èhnlicher Daten aus der Flasergranitoid-Zone und dem Frankenstein-Komplex die Bedeutung der Scherzone zwischen diesen beiden Einheiten hervorhebt. Unsere P-T-Daten zeigen auûerdem, daû die Hochtemperatur-Niederdruck-Metamorphose im Bergstra Èsser Odenwald nicht notwendigerweise eine Regionalmetamorphose sein muû, sondern ebenso gut als Kontaktmetamorphose interpretiert werden kann.

Proceedings, 2015

We did multi-stage triaxial compressive strength tests in conjunction with 3D in situ stress dete... more We did multi-stage triaxial compressive strength tests in conjunction with 3D in situ stress determinations (applying the RACOS® technique) on Middle Jurassic silt- and sandstones from the North Sea Basin which are the caprock of a hydrocarbon reservoir. The achieved data served as basis for a geomechanical safety model of a hydrocarbon reservoir / hypothetical underground gas storage. The rock mechanical tests revealed the siltstone to be slightly stronger and stiffer than the sandstone. Of particular interest for the geomechanical model (based on the centroid model of Finkbeiner et al. 2001) are the angles of internal friction measured at post-failure conditions (φresidual) which lie between 27° (siltstone) and 32° (sandstone). RACOS® investigations showed that the stress field in the reservoir is of normal faulting nature with a total vertical stress S1 of ca 61 MPa and the minimum total horizontal stress S3 of ca 49 MPa (oriented NNW-SSE). For our geomechanical model we applied beside φresidual , S1 and S3 the pore pressure within the caprock Ppc of roughly 32 MPa. Based on these data our model shows that pore pressure within the reservoir can be up to 10 MPa above Ppc without reactivating inactive faults within the caprock.

We propose a new method for earthquake forecasting based on the "prediction in hindsight... more We propose a new method for earthquake forecasting based on the "prediction in hindsight" of a Mw 5.8 earthquake on Iceland, on September 16, 2002. The "prediction in hindsight" is based on geochemical monitoring of geothermal water at site HU-01 located within the Tj''rnes Fracture Zone, northern Iceland, before and after the earthquake. During the 4 weeks before the earthquake

Safety of Nuclear Waste Disposal

Uranium mining and milling is where the nuclear fuel chain starts. Nevertheless, it is the most d... more Uranium mining and milling is where the nuclear fuel chain starts. Nevertheless, it is the most disregarded part of this chain when thinking about resilience and safety, both in academic debates and in the process of resource extraction. This workshop aims at addressing this gap in addition to improving our understanding of the lessons we can learn for nuclear waste disposal. Uranium mining and milling is challenging when considering safety, from the first day a mine is in operation to the final day of land rehabilitation. During the operation of the mine and mill, the health of the miners is at risk and so is the well-being of the population living in the surrounding area of the mine and the ore-processing plant. Moreover, environmental issues such as pollution pose a risk during the entire lifetime of a mine. The remnants of mining activities can be regarded as long-term liabilities, since they must be monitored for many generations. Uranium mining and milling facilities are often situated on the land of indigenous people. Their rights to information and their participation in the decision-making processes regarding the mining operations, in addition to being informed about basic health outcomes, were and frequently continue to not be given, leading to injustices by mining companies and governmental authorities. Participation, however, is crucial for positive societal outcomes, such as avoiding the deepening of structural inequalities and the development of violent conflict, and for building trust-and thus also for security. This is not only true for operations at the beginning of the nuclear fuel chain but also for actions taken at the end (i.e., during the quest for the safest possible disposal site for nuclear waste). Based on insights from the processes of uranium extraction, we can draw conclusions about the site selection process of a final repository, specifically regarding licensing, operation and land rehabilitation processes. Bearing this in mind, it is worth having a detailed look at the beginning of the nuclear fuel chain as we move forward to resolve the issues we will face during the final stage of nuclear waste disposal. Learning in this context means looking closely at the processes during the licensing, operation, closure and rehabilitation of uranium mines and mills and drawing conclusions about the site selection process, in particular with respect to inclusion of the individual stakeholders and safety concepts. As a result, we can develop recommendations for the ongoing revision of the search process for a final repository for radioactive waste. Therefore, safety and participation issues are the focus of the uranium mining and milling workshop. The workshop will gather academics and practitioners from different fields in a transdisciplinary setting. We plan about five short inputs (up to 10 min each) based on some visualizations (slides, posters or similar), followed by a World Café related to the input talks and a concluding plenary discussion. The entire workshop will last about 2.5 h. The workshop is topped off by an excursion to the Wismut facilities in Ronneburg (Thüringen/Thuringia, Germany) on the Saturday after the conference. The field trip will be guided by Wismut GmbH, the Church Environmental Group Ronneburg and the local Miners' Association. This workshop will enhance the transdisciplinary capabilities of the participants with respect to the logic and externalities of uranium extraction, in addition to providing opportunities for exchange and networking. We aim to compose a publication format for the Safety of Nuclear Waste Disposal platform, based on the contributions of all workshop participants.

Geotectonic Research, 2008

IJInstitut fur Geowissenschaften, Johann Wolfgang Goethe Universitat, AltenhOferallee 1,0-60348 F... more IJInstitut fur Geowissenschaften, Johann Wolfgang Goethe Universitat, AltenhOferallee 1,0-60348 Frankfurt am Main, Germany E-Mail: jungmann@stud.uni-frankfurt.de 2JInstitut fur Geologie der Friedrich-Alexander Universitat Erlangen-Nlirnberg, SchloBgarten 5, 0-91054 Erlangen, ...

Journal of GEOsciences, 2012

Geophysical investigations reveal that many granitoid plutons possess a tabular shape: either lac... more Geophysical investigations reveal that many granitoid plutons possess a tabular shape: either laccolithic, lopolithic or phacolithic. In this study, the results of a centrifuge experiment are used to understand the formation mechanisms of these features. The model was build of a sequence of 14 differently coloured plasticine layers. Two buoyant layers -with a volume of c. 40 cm 3 each -were incorporated into the model stratigraphy at different depths to investigate, whether the rise and emplacement of buoyant material at different levels results in different intrusion structures. After centrifuging for 30 min at 700 G, both the buoyant layers had formed two lenticular sills (phacoliths) with aspect ratios (length/thickness) of 6 and 3.4 for the upper and lower phacoliths, respectively, directly above both pre-existing perturbations in the buoyant layers. During their movement, the buoyant phacoliths had pushed their roof plasticine upward. Simultaneously, their floor plasticine had subsided (bottom sinking). Subsidence of the floor material had choked the inflow of further buoyant material into the feeder channel of the developing sills and inhibited their further lateral growth. The observed forced downward movement of the plasticine floor of the forming PDMS (polydimethylsiloxane) phacoliths resembles the so-called "floor depression" of host rock material around an emplacing tabular pluton. Floor depression is supposed to be a very important vertical material transfer process, which provides space for the construction of lopoand phacoliths. The subsidence of host material made space for the developing buoyant phacoliths, but also restricted their growth to a certain time slot before the influx of new buoyant material into the feeder dyke of the tabular intrusive body was shut off. Similarly, in nature, the growth of a tabular pluton might be limited not only by the rate of magma ascent and its physical properties, but also by the emplacement processes of the evolving pluton.

Geotectonic Research, 2008

Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 2008

In the Hauzenberger pluton of East Bavaria two granites, (Hauz I and II) and a granodiorite are d... more In the Hauzenberger pluton of East Bavaria two granites, (Hauz I and II) and a granodiorite are distinguished. Their magnetic susceptibility, measured in the field using a portable susceptometer, is low, but clear differences appear between the granodiorite (84 x 10 -6 SI) and both granite types (52 x 10 -6 SI ). These differences are related to the variable content in biotite and muscovite. Based on systematic magnetic susceptibility measurement at 372 sites, a susceptibility contour map of the Hauzenberg pluton was drawn. There is a good agreement between the spatial distribution of the different lithotypes of the pluton and the areas of iso-susceptibility values. Susceptibility measurements on rock-floats can be considered as reliable in the frame of the contoured susceptibility map, thus allowing the implementation of float data sets into the magnetic susceptibility mapping routine.

Lithos, 2010

Tube-like schlieren structures occur at the boundary between two units of the Fürstenstein Intrus... more Tube-like schlieren structures occur at the boundary between two units of the Fürstenstein Intrusive Complex, the Tittling and the Saldenburg granites. We have analysed the magnetic fabrics, petrographic variation and geochemistry of key examples of these structures in order to test the hypothesis that they originated as granitic microdiapirs. The rims of the schlieren structures have high magnetic susceptibility compared to their interiors and surrounding granite due to the enrichment of biotite ± opaques. The low anisotropy that characterizes the AMS fabric is probably caused by magmatic flow. Hypersolidus microfabrics support this interpretation. Magnetic fabric orientation within the schlieren structures differs significantly from the NE-SW-trending magnetic foliation generally observed within the hosting Tittling granite. A steeply plunging magnetic lineation and a NNE-SSW girdle distribution of the magnetic foliation poles within the schlieren structures are consistent with the conical geometry of the schlieren structures evolved during the rise of the magma. Based on geochemistry, granite in the schlieren structures is interpreted to be differentiated melt expelled from the Tittling granite mush that formed after early crystallization of plagioclase. We suggest that the schlieren structures are pockets of residual melt of the Tittling granite that were mobilized buoyantly due to a thermal input from the neighbouring Saldenburg granite. The mafic rims of the schlieren structures formed as a result of early crystallization and subsequent accumulation due of the Bagnold effect. The results of the magnetic and geochemical investigations allow us to interpret the schlieren structures as diapiric in nature and consequently as "within-chamber diapirs" (sensu .

Journal of the Virtual Explorer, 2002

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Journal of the Geological Society, 2008

Analogue models are used to study the mechanical relationship between basement strike-slip faults... more Analogue models are used to study the mechanical relationship between basement strike-slip faults and salt diapirs. Displacement along a strike-slip fault in 1 g models resulted in extension along pre-existing jogs and the formation of oblique extensional faults, where reactive diapirs were triggered in some models. In the centrifuge models, prescribed cuts, simulating pre-existing structures, were reactivated during simple shear deformation of the models, resulting in formation of pull-apart basins, which were intruded by diapirs. The models show that because of the low ratio of salt to overburden thickness in the Zagros (0.15-0.35), it is unlikely that diapirs have formed solely, if at all, as a result of movement along basement strike-slip faults. Two mechanisms are suggested. First, pre-kinematic thin overburden and continuous movement along a releasing bend in the cover units may have triggered some of the diapirs in the Zagros, which were later downbuilt to their current geometry by additional sedimentation. Second, movement along the strike-slip faults (e.g. the Kazerun and Mangarak faults) induced oblique movement along NW-SE Zagros structures (folds or thrusts) resulting in the formation of pull-apart basins where diapirs were eventually intruded. Fault plane solution of shallow earthquakes supports the second scenario, which is also in agreement with previous interpretations that some of the salt diapirs associated with basement faults are younger than Zagros shortening and young southwestwards.

Journal of Structural Geology, 2011

We carried out a centrifuge experiment to model the diapiric rise of a stratified PDMS layer from... more We carried out a centrifuge experiment to model the diapiric rise of a stratified PDMS layer from three perturbations through a non-Newtonian, ductile overburden. The experiment carried out at 700 g resulted in three composite diapirs fed by different PDMS layers. The three resulting diapirs represent two different stages of diapirism. One of the diapirs (diapir 1), which reached its level of neutral buoyancy and extruded at the surface of the model, was tabular in profile and copied by an internal intrusive body. The other two diapirs (diapirs 2 ...

Journal of African Earth Sciences, 2014

Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyp... more Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyphase, late Pan-African deformational evolution in the Um Sheqila-Um Had (595 Ma) composite pluton and in the Hammamat and Atalla areas of the Central Eastern Desert of Egypt in Ediacaran times. Major stages are early shortening (NNW-SSE), subsequent strike-slip (NW-SE shear zones), and late shortening (NW-SE). Strain studies on pebbles and xenoliths together with AMS data show a predominance of shallow, NW-SE trending X axes or magnetic lineations, associated with steep, NW-SE striking magnetic foliations. Magnetic fabrics and microstructures indicate a tectonic fabric in the Um Sheqila-Um Had granitoid plutons, which is dominated by steep NW-SE striking foliations and shallow NW-SE trending lineations, similar to those in the high-angle Atalla Shear Zone. There is a change of lineation directions from ESE-WNW at Um Sheqila (oldest) to NW-SE to Um Had II (youngest). This pattern may indicate an influence of strike-slip and is also consistent with NE-SW compression. This holds also true for the asymmetry of the contact aureole, which is extended towards NW, parallel with the trend of the magnetic lineation. The character and orientation of the deformation pattern in the Um Sheqila-Um Had plutons and the Atalla Shear Zone is thus similar to the pattern of the late shortening phase. The intrusion of the Um Sheqila-Um Had granitoid rocks, therefore, took place before the late shortening stage, but postdates early deformation, which, according to published data, was associated with lithospheric thinning in the Central Eastern Desert. Therefore, these Pan-African plutons do not represent the earliest postdeformational intrusions but a late stage of syn-deformational magmatic activity. At a regional scale, this deformation with steep foliations and shallow lineations may also be related with lateral escape tectonics. The pluton emplacement, the importance of transcurrent shear zones, and the low lithospheric thickness in the area are not consistent with tectonic elements at the Pan-African orogenic margin but imply a more internal position for the Wadi Hammamat area.

Safety of nuclear waste disposal, Sep 5, 2023

This paper presents a road map for providing training to experienced geoscientists, engineers, an... more This paper presents a road map for providing training to experienced geoscientists, engineers, and data scientists who seek to participate in geothermal energy exploration, development, and integration. The road map starts by identifying the foundational skills and knowledge base of experienced geoscientists and engineers, and then specifically discusses which elements are of direct value in geothermal energy development. The paper then discusses the best strategies for upscaling skills and closing knowledge gaps, as well as pathways for immediate implementation of the knowledge in the form of planning documents and projects. The final stage of the road map includes assessment and designing collaborative challenges so that teams learn how best to work together and achieve their goals. The final section of the paper includes brief case studies of two examples of retooled geothermal education offered by the American Association of Petroleum Geologists (AAPG).

In this study, interaction between fluids and deformation during the final stages of magma-poor r... more In this study, interaction between fluids and deformation during the final stages of magma-poor rifting was investigated. The Tasna Ocean-Continent transition, located in the Swiss Alps, was studied and a large data set was obtained from profiles oriented perpendicular to two detachment faults. One of these juxtaposed serpentinized mantle against continental crust and the other exhumed both mantle and continental crust to the seafloor. Deformation associated with detachment faulting showed many common features but also some phenomena which were unique to each fault, confirming their sequential activity and differing roles in the exhumation process. Oxygen isotopes indicated the presence of both pervasive and channeled fluid phases, either accompanying or post-dating serpentinization. Deformation in the fault zone occurred in previously serpentinized mantle indicating that serpentinization pre-dated final exhumation. Most strain localization and displacement occurred in fault cores which are narrow zones beneath the detachments. These are underlain by wide zones characterized by more distributed strain. Transitional fabrics as well as reactivated and/or overprinted deformation structures indicated that the final phase of rifting is complex. Fault cores acted as fluid conduits or barriers. Thus, the most deformed zones may become the least permeable. Hence the coupling between deformation and fluid flow is complex in a study area subjected to several phases of deformation and fluid flow. Finally the importance of serpentinization in the evolution of magma-poor rifting was investigated. It was found that serpentinization is the consequence rather than the reason for strain localization at magma-poor margins. However, serpentinization may be an important process which can accelerate exhumation rates in the very latest stages of magma-poor rifting. The pre-existing deformation history of the crust may also be of importance for the development and location of margins.

Mineralogy and Petrology, Jun 12, 2001

The three major units of the Bergstra Èsser Odenwald (Frankenstein Complex, Flasergranitoid Zone ... more The three major units of the Bergstra Èsser Odenwald (Frankenstein Complex, Flasergranitoid Zone and southern Bergstra Èsser Odenwald) are, according to literature, separated by two major shear zones. The aim of the present paper is to evaluate the importance of these sutures by comparing new hornblende geothermobarometry data from ®ve plutons of the Flasergranitoid Zone with published P-T data from the entire Bergstra Èsser Odenwald. Furthermore radiometric, geochemical and structural data from the literature were also used for this purpose. Temperatures were calculated with the amphibole-plagioclase thermometer and range from 600 to 800 C. Determinations of the intrusion depth, using the Al-in-hornblende barometer show that most plutons intruded at pressures ranging from about 4 to 6 kbar (13 to 20 km). These combined data do not allow to postulate a major suture zone between the Flasergranitoid Zone and the southern Bergstra Èsser Odenwald, while comparison of similar data from the Flasergranitoid Zone and the Frankenstein Complex verify the importance of this shear zone. Moreover, our P-T data show that the high temperature ± low pressure metamorphism in the Bergstra Èsser Odenwald can also be interpreted as contact metamorphism and not necessarily as regional metamorphism. Zusammenfassung Hornblende-Thermobarometrie an Granitoiden des Mittleren Odenwaldes (Deutschland) und ihre Implikation fu Èr die geotektonische Entwicklung des Odenwaldes Die drei Haupteinheiten des Bergstra Èsser Odenwaldes (Frankenstein-Komplex, Flasergranitoid-Zone und su Èdlicher Bergstra Èsser Odenwald) werden nach der Literatur durch zwei bedeutende Scherzonen voneinander getrennt. Ziel der vorliegenden Arbeit ist es, die wirkliche Bedeutung dieser beiden Suturen herauszuarbeiten. Dazu wurden eigene, neue Hornblende-Geothermobarometrie-Daten, die an fu Ènf Plutonen der Flasergranitoidzone ermittelt wurden, mit bereits publizierten P-T-Daten aus dem gesamten Bergstra Èsser Odenwald verglichen. Zudem wurden radiometrische, geochemische und strukturgeologische Datensa Ètze aus der Literatur fu Èr diesen Zweck benutzt. Kristallisationstemperaturen wurden mit Hilfe des Amphibol-Plagioklas-Thermometers errechnet und liegen zwischen 600 und 800 C. Die Bestimmung der Intrusionstiefe mit dem Al-in-Hornblende-Barometer ergab fu Èr die meisten Plutone Dru Ècke im Bereich von 4± 6 kbar (13±20 km). Diese, sowie radiometrische, geochemische und strukturgeologische Daten aus der Flasergranitoid-zone und dem su Èdlichen Bergstra Èsser Odenwald geben keinen Hinweis auf eine wichtige Suturzone zwischen diesen beiden geotektonischen Einheiten, wohingegen der Vergleich a Èhnlicher Daten aus der Flasergranitoid-Zone und dem Frankenstein-Komplex die Bedeutung der Scherzone zwischen diesen beiden Einheiten hervorhebt. Unsere P-T-Daten zeigen auûerdem, daû die Hochtemperatur-Niederdruck-Metamorphose im Bergstra Èsser Odenwald nicht notwendigerweise eine Regionalmetamorphose sein muû, sondern ebenso gut als Kontaktmetamorphose interpretiert werden kann.

Proceedings, 2015

We did multi-stage triaxial compressive strength tests in conjunction with 3D in situ stress dete... more We did multi-stage triaxial compressive strength tests in conjunction with 3D in situ stress determinations (applying the RACOS® technique) on Middle Jurassic silt- and sandstones from the North Sea Basin which are the caprock of a hydrocarbon reservoir. The achieved data served as basis for a geomechanical safety model of a hydrocarbon reservoir / hypothetical underground gas storage. The rock mechanical tests revealed the siltstone to be slightly stronger and stiffer than the sandstone. Of particular interest for the geomechanical model (based on the centroid model of Finkbeiner et al. 2001) are the angles of internal friction measured at post-failure conditions (φresidual) which lie between 27° (siltstone) and 32° (sandstone). RACOS® investigations showed that the stress field in the reservoir is of normal faulting nature with a total vertical stress S1 of ca 61 MPa and the minimum total horizontal stress S3 of ca 49 MPa (oriented NNW-SSE). For our geomechanical model we applied beside φresidual , S1 and S3 the pore pressure within the caprock Ppc of roughly 32 MPa. Based on these data our model shows that pore pressure within the reservoir can be up to 10 MPa above Ppc without reactivating inactive faults within the caprock.

We propose a new method for earthquake forecasting based on the "prediction in hindsight... more We propose a new method for earthquake forecasting based on the "prediction in hindsight" of a Mw 5.8 earthquake on Iceland, on September 16, 2002. The "prediction in hindsight" is based on geochemical monitoring of geothermal water at site HU-01 located within the Tj''rnes Fracture Zone, northern Iceland, before and after the earthquake. During the 4 weeks before the earthquake

Safety of Nuclear Waste Disposal

Uranium mining and milling is where the nuclear fuel chain starts. Nevertheless, it is the most d... more Uranium mining and milling is where the nuclear fuel chain starts. Nevertheless, it is the most disregarded part of this chain when thinking about resilience and safety, both in academic debates and in the process of resource extraction. This workshop aims at addressing this gap in addition to improving our understanding of the lessons we can learn for nuclear waste disposal. Uranium mining and milling is challenging when considering safety, from the first day a mine is in operation to the final day of land rehabilitation. During the operation of the mine and mill, the health of the miners is at risk and so is the well-being of the population living in the surrounding area of the mine and the ore-processing plant. Moreover, environmental issues such as pollution pose a risk during the entire lifetime of a mine. The remnants of mining activities can be regarded as long-term liabilities, since they must be monitored for many generations. Uranium mining and milling facilities are often situated on the land of indigenous people. Their rights to information and their participation in the decision-making processes regarding the mining operations, in addition to being informed about basic health outcomes, were and frequently continue to not be given, leading to injustices by mining companies and governmental authorities. Participation, however, is crucial for positive societal outcomes, such as avoiding the deepening of structural inequalities and the development of violent conflict, and for building trust-and thus also for security. This is not only true for operations at the beginning of the nuclear fuel chain but also for actions taken at the end (i.e., during the quest for the safest possible disposal site for nuclear waste). Based on insights from the processes of uranium extraction, we can draw conclusions about the site selection process of a final repository, specifically regarding licensing, operation and land rehabilitation processes. Bearing this in mind, it is worth having a detailed look at the beginning of the nuclear fuel chain as we move forward to resolve the issues we will face during the final stage of nuclear waste disposal. Learning in this context means looking closely at the processes during the licensing, operation, closure and rehabilitation of uranium mines and mills and drawing conclusions about the site selection process, in particular with respect to inclusion of the individual stakeholders and safety concepts. As a result, we can develop recommendations for the ongoing revision of the search process for a final repository for radioactive waste. Therefore, safety and participation issues are the focus of the uranium mining and milling workshop. The workshop will gather academics and practitioners from different fields in a transdisciplinary setting. We plan about five short inputs (up to 10 min each) based on some visualizations (slides, posters or similar), followed by a World Café related to the input talks and a concluding plenary discussion. The entire workshop will last about 2.5 h. The workshop is topped off by an excursion to the Wismut facilities in Ronneburg (Thüringen/Thuringia, Germany) on the Saturday after the conference. The field trip will be guided by Wismut GmbH, the Church Environmental Group Ronneburg and the local Miners' Association. This workshop will enhance the transdisciplinary capabilities of the participants with respect to the logic and externalities of uranium extraction, in addition to providing opportunities for exchange and networking. We aim to compose a publication format for the Safety of Nuclear Waste Disposal platform, based on the contributions of all workshop participants.

Geotectonic Research, 2008

IJInstitut fur Geowissenschaften, Johann Wolfgang Goethe Universitat, AltenhOferallee 1,0-60348 F... more IJInstitut fur Geowissenschaften, Johann Wolfgang Goethe Universitat, AltenhOferallee 1,0-60348 Frankfurt am Main, Germany E-Mail: jungmann@stud.uni-frankfurt.de 2JInstitut fur Geologie der Friedrich-Alexander Universitat Erlangen-Nlirnberg, SchloBgarten 5, 0-91054 Erlangen, ...

Journal of GEOsciences, 2012

Geophysical investigations reveal that many granitoid plutons possess a tabular shape: either lac... more Geophysical investigations reveal that many granitoid plutons possess a tabular shape: either laccolithic, lopolithic or phacolithic. In this study, the results of a centrifuge experiment are used to understand the formation mechanisms of these features. The model was build of a sequence of 14 differently coloured plasticine layers. Two buoyant layers -with a volume of c. 40 cm 3 each -were incorporated into the model stratigraphy at different depths to investigate, whether the rise and emplacement of buoyant material at different levels results in different intrusion structures. After centrifuging for 30 min at 700 G, both the buoyant layers had formed two lenticular sills (phacoliths) with aspect ratios (length/thickness) of 6 and 3.4 for the upper and lower phacoliths, respectively, directly above both pre-existing perturbations in the buoyant layers. During their movement, the buoyant phacoliths had pushed their roof plasticine upward. Simultaneously, their floor plasticine had subsided (bottom sinking). Subsidence of the floor material had choked the inflow of further buoyant material into the feeder channel of the developing sills and inhibited their further lateral growth. The observed forced downward movement of the plasticine floor of the forming PDMS (polydimethylsiloxane) phacoliths resembles the so-called "floor depression" of host rock material around an emplacing tabular pluton. Floor depression is supposed to be a very important vertical material transfer process, which provides space for the construction of lopoand phacoliths. The subsidence of host material made space for the developing buoyant phacoliths, but also restricted their growth to a certain time slot before the influx of new buoyant material into the feeder dyke of the tabular intrusive body was shut off. Similarly, in nature, the growth of a tabular pluton might be limited not only by the rate of magma ascent and its physical properties, but also by the emplacement processes of the evolving pluton.

Geotectonic Research, 2008

Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 2008

In the Hauzenberger pluton of East Bavaria two granites, (Hauz I and II) and a granodiorite are d... more In the Hauzenberger pluton of East Bavaria two granites, (Hauz I and II) and a granodiorite are distinguished. Their magnetic susceptibility, measured in the field using a portable susceptometer, is low, but clear differences appear between the granodiorite (84 x 10 -6 SI) and both granite types (52 x 10 -6 SI ). These differences are related to the variable content in biotite and muscovite. Based on systematic magnetic susceptibility measurement at 372 sites, a susceptibility contour map of the Hauzenberg pluton was drawn. There is a good agreement between the spatial distribution of the different lithotypes of the pluton and the areas of iso-susceptibility values. Susceptibility measurements on rock-floats can be considered as reliable in the frame of the contoured susceptibility map, thus allowing the implementation of float data sets into the magnetic susceptibility mapping routine.

Lithos, 2010

Tube-like schlieren structures occur at the boundary between two units of the Fürstenstein Intrus... more Tube-like schlieren structures occur at the boundary between two units of the Fürstenstein Intrusive Complex, the Tittling and the Saldenburg granites. We have analysed the magnetic fabrics, petrographic variation and geochemistry of key examples of these structures in order to test the hypothesis that they originated as granitic microdiapirs. The rims of the schlieren structures have high magnetic susceptibility compared to their interiors and surrounding granite due to the enrichment of biotite ± opaques. The low anisotropy that characterizes the AMS fabric is probably caused by magmatic flow. Hypersolidus microfabrics support this interpretation. Magnetic fabric orientation within the schlieren structures differs significantly from the NE-SW-trending magnetic foliation generally observed within the hosting Tittling granite. A steeply plunging magnetic lineation and a NNE-SSW girdle distribution of the magnetic foliation poles within the schlieren structures are consistent with the conical geometry of the schlieren structures evolved during the rise of the magma. Based on geochemistry, granite in the schlieren structures is interpreted to be differentiated melt expelled from the Tittling granite mush that formed after early crystallization of plagioclase. We suggest that the schlieren structures are pockets of residual melt of the Tittling granite that were mobilized buoyantly due to a thermal input from the neighbouring Saldenburg granite. The mafic rims of the schlieren structures formed as a result of early crystallization and subsequent accumulation due of the Bagnold effect. The results of the magnetic and geochemical investigations allow us to interpret the schlieren structures as diapiric in nature and consequently as "within-chamber diapirs" (sensu .

Journal of the Virtual Explorer, 2002

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Journal of the Geological Society, 2008

Analogue models are used to study the mechanical relationship between basement strike-slip faults... more Analogue models are used to study the mechanical relationship between basement strike-slip faults and salt diapirs. Displacement along a strike-slip fault in 1 g models resulted in extension along pre-existing jogs and the formation of oblique extensional faults, where reactive diapirs were triggered in some models. In the centrifuge models, prescribed cuts, simulating pre-existing structures, were reactivated during simple shear deformation of the models, resulting in formation of pull-apart basins, which were intruded by diapirs. The models show that because of the low ratio of salt to overburden thickness in the Zagros (0.15-0.35), it is unlikely that diapirs have formed solely, if at all, as a result of movement along basement strike-slip faults. Two mechanisms are suggested. First, pre-kinematic thin overburden and continuous movement along a releasing bend in the cover units may have triggered some of the diapirs in the Zagros, which were later downbuilt to their current geometry by additional sedimentation. Second, movement along the strike-slip faults (e.g. the Kazerun and Mangarak faults) induced oblique movement along NW-SE Zagros structures (folds or thrusts) resulting in the formation of pull-apart basins where diapirs were eventually intruded. Fault plane solution of shallow earthquakes supports the second scenario, which is also in agreement with previous interpretations that some of the salt diapirs associated with basement faults are younger than Zagros shortening and young southwestwards.

Journal of Structural Geology, 2011

We carried out a centrifuge experiment to model the diapiric rise of a stratified PDMS layer from... more We carried out a centrifuge experiment to model the diapiric rise of a stratified PDMS layer from three perturbations through a non-Newtonian, ductile overburden. The experiment carried out at 700 g resulted in three composite diapirs fed by different PDMS layers. The three resulting diapirs represent two different stages of diapirism. One of the diapirs (diapir 1), which reached its level of neutral buoyancy and extruded at the surface of the model, was tabular in profile and copied by an internal intrusive body. The other two diapirs (diapirs 2 ...

Journal of African Earth Sciences, 2014

Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyp... more Field investigations, microstructural observations, and magnetic fabric analyses revealed a polyphase, late Pan-African deformational evolution in the Um Sheqila-Um Had (595 Ma) composite pluton and in the Hammamat and Atalla areas of the Central Eastern Desert of Egypt in Ediacaran times. Major stages are early shortening (NNW-SSE), subsequent strike-slip (NW-SE shear zones), and late shortening (NW-SE). Strain studies on pebbles and xenoliths together with AMS data show a predominance of shallow, NW-SE trending X axes or magnetic lineations, associated with steep, NW-SE striking magnetic foliations. Magnetic fabrics and microstructures indicate a tectonic fabric in the Um Sheqila-Um Had granitoid plutons, which is dominated by steep NW-SE striking foliations and shallow NW-SE trending lineations, similar to those in the high-angle Atalla Shear Zone. There is a change of lineation directions from ESE-WNW at Um Sheqila (oldest) to NW-SE to Um Had II (youngest). This pattern may indicate an influence of strike-slip and is also consistent with NE-SW compression. This holds also true for the asymmetry of the contact aureole, which is extended towards NW, parallel with the trend of the magnetic lineation. The character and orientation of the deformation pattern in the Um Sheqila-Um Had plutons and the Atalla Shear Zone is thus similar to the pattern of the late shortening phase. The intrusion of the Um Sheqila-Um Had granitoid rocks, therefore, took place before the late shortening stage, but postdates early deformation, which, according to published data, was associated with lithospheric thinning in the Central Eastern Desert. Therefore, these Pan-African plutons do not represent the earliest postdeformational intrusions but a late stage of syn-deformational magmatic activity. At a regional scale, this deformation with steep foliations and shallow lineations may also be related with lateral escape tectonics. The pluton emplacement, the importance of transcurrent shear zones, and the low lithospheric thickness in the area are not consistent with tectonic elements at the Pan-African orogenic margin but imply a more internal position for the Wadi Hammamat area.