In the on-going push for developing new, eco-friendly resources and energy production, the potential of naturally occurring hydrogen, generated through the alteration (serpentinization) of tectonically exhumed mantle rocks, remains largely overlooked. The exhumation of mantle rocks can occur during rifting and continental break-up, but as well as during mountain building phases. In order to better assess the opportunities for natural hydrogen extraction from exhumed mantle material, we must improve our understanding of the tectonic processes leading to (and active during) their exhumation.
This project envisions the use of numerical tectonic modelling techniques to unravel these mantle exhumation proce cesses, with a special focus on the influence of structural inheritance, pressure and temperature evolution of exhumed mantle materials over time, and the importance of surface processes and the presence of reservoirs. The subsequent aim is to apply these modelling results to interpret the tectonic history of various natural cases (e.g. Pyrenees, offshore Iberia, European Alps), and to assess the feasibility of natural hydrogen extraction in these areas of interest.
The East African Rift System (EARS) encompasses a wide variety of rifts including the immature Malawi rift in the south to the highly extended, seismically and volcanically active Afar rift to the north. The Afar rift offers an excellent opportunity to investigate continental break up and the formation of seafloor spreading centers on land. The opening of the Afar rift started at ∼30 million years ago (Myr), facilitated by the Afar plume and separation of Arabia from Africa and later by the rotation of the Danakil and Ali-Sabeh blocks at ∼7 Myr. Significant rift formation and propagation in central Afar occured at around 4 Myr.
The Quaternary to Recent opening of the Afar rift is mainly accommodated at the Dabbahu-Manda Harraro (DMH) and Asal-Ghobbet (ASAL) segments, at the tip of the Red Sea and Gulf of Aden rifts, respectively. However, how the two rift segments propagate towards each other is still enigmatic. Several contrasting models have been put forward to explain the rift propagation and linkage in the Afar rift. The discrepancy among these models could be due to the difference in timescale of observations. Here we aim to combine GPS and numerical geodynamic modeling observations coupled with paleomagnetic and earthquake data to fully understand rift propagation and linkage in the central Afar across the range of timescale.
Project duration: 2021 − 2023
Funding agency: Alexander von Humboldt Foundation
Primary Investigator: Ameha A. Muluneh
Collaborators: Sascha Brune, Derek Keir (University of Southampton, UK), Giacomo Corti (National Research Council of Italy, Italy), Carolina Pagli (University of Pisa, Italy), Tesfaye Kidane (University of Kwazulu Natal, South Africa)
Plate tectonics plays a major role in the evolution of Earth’s surface as it changes constantly the position of the continents and oceans through time, directly affecting the biosphere, cryosphere and atmosphere. The Neoproterozoic (1000-541 Ma) is a period of extreme changes during which major events occurred in the superficial layers of the planet (atmospheric oxygenation, biological diversification, intense changes in geochemical cycles). It may also correspond to a period of important changes in the tectonic regime with plate tectonics evolving from an episodic to a continuous plate tectonic mode as seen today. It is therefore crucial to understand how paleogeography and its relationship with mantle dynamics has evolved during this critical period of time.
Paleomagnetism is a central tool to study plate tectonics in the past as it allows one to determine motions of the surface relative to the spin axis back in time and therefore to elaborate plate reconstructions. In this theme, we elaborate paleogeographic reconstructions using paleomagnetism, geology and the analysis of True Polar Wander to better constrain the evolution of plate tectonics during this crucial time. Coupled with modelling of mantle dynamics, we investigate the links between plate tectonics and mantle flow to explore their evolution during the Neoproterozoic
Rifted margins are a key setting for the deposition of thick evaporites because of the restrictive environments and shallow water depths. Here we focus on the distribution and deformation characteristics of the thick Lower Cretaceous salt deposits in the Central South Atlantic conjugated basins. Previous studies have shown that salt tectonics at rifted margins result from gravity instability driven by the combined effects of the margin tilt and the progressive sedimentary loading. Based on the previous work, the project will employ the numerical modelling tools ASPECT to analyze in detail the effects of tectonic deformation, rheological conditions and surface process on the deformation mode of salt during and after extension. This insight has the potential to elucidate a number of key features of salt tectonics in the Central South Atlantic passive margin.
Similar to many passive margins worldwide, the formation of the rifted continental margins of the South China Sea (SCS) features a complex tectonic history progressing from rift localization and lithospheric thinning to continental break-up and seafloor spreading. It is clear that the tectonic history of the SCS has been affected by several key regional factors, such as Mesozoic inherited structures and the initial thermal regime of a back-arc setting. In addition, a very recent IODP cruise provided compelling evidence that the common end-number scenarios of magma-rich or magma-poor rifted margins do not apply to the SCS. Based on the current research, this project will address the questions why and how the back-arc regime leads to the distinct tectonic history and final architecture of the SCS rifted margins. Using the state-of-the-art numerical modelling tools, the program will focus on the cross-scale geodynamic evolution of the SCS and its thermal evolution.
This project aims at constraining the dynamics of LLSVPs, their deformation pattern and composition using the shear wave anisotropy of the lowermost mantle. The lowermost mantle, specifically the D” layer, is very difficult to explore due to the scarcity of seismic observations in that great depth. The two large low shear velocity provinces (LLSVPs) in the D” layer exhibit characteristic physico-chemical properties unlike the surrounding mantle. Although the plumes are being generated from these structures, the composition of plumes and LLSVPs are not the same. Using 3D numerical modelling of mantle convection, I will model the seismic anisotropy generated from different deformation mechanisms in the lower mantle and compare them with the observations. The deformation mechanisms and the flow pattern will tell us about the rheological property as well as the density structure of the LLSVPs. Adding to that, I will also try to address the geochemical composition of the D” layer with special focus on LLSVPs.
An ERC (European Research Council) Synergy grant of €12.8 million over six years (2020-2026) has been awarded to Alexander Sobolev (IsTerre, Grenoble), Stephan Sobolev (GFZ Potsdam, Germany) and John Valley (University of Wisconsin, Madison, USA) to study the evolution of Earth’s chemical composition and the underlying physical processes from 4.4 billion years ago to present in a project entitled “Monitoring Earth Evolution through Time” (MEET).
EWRICA aims at calculation of robust local ground motion models shortly after an earthquake to assess secondary effects such as tsunamis and landslides as well as to identify areas of possible building damage and collapse. This should be achieved by, firstly, improving the accuracy of real-time GNSS processing to a cm-level with optionally collocated accelerometers (GFZ Section 1.1). Precise surface displacements will then be fed into the real-time source inversion (GFZ Section 2.1). The improved source assessment will allow more reliable prediction of ground motion (Dr. Matthias Ohrnberger, Uni Potsdam) which, in turn, will improve forecasting of secondary effects like landsliding and tsunami generation. At the end of the project, operational system prototype (GFZ Section 2.4) will be installed by our international partners: INGV (Italy) and NOA (Greece).
Understanding of how, when and where a subduction zone initiates is still one of the most enigmatic issues in geosciences. Various localities such as intra-oceanic transform faults/fracture zones, extinct mid-oceanic ridges and passive margins have been proposed as likely sites where new subduction zones are to begin. Geological observations confirm subduction initiation along some of these proposed locations. However, lack of Cenozoic examples makes subduction initiation along passive margins more controversial, even though the concept continues to be widely promulgated. The broad acceptance of passive margins as favourable site for trench formation comes from the key role that they play in Wilson cycle, which explains the repeated opening and closing of ocean basins in geological time.
Most previous modelling studies have not succeeded in simulating conversion of an old passive margin into a subduction zone with realistic parameters. Here we aim to contribute to progress on this important geo-scientific problem by addressing the following questions: What are the conditions under which an old oceanic lithosphere adjacent to a passive continental margin can spontaneously collapse and begin to subduct? If spontaneous subduction initiation is impossible, can mantle flow associated with past and present subduction zones convert a passive continental margin into a subduction zone?
Great earthquakes are a catastrophic corollary of long-term plate tectonics that pose a major threat to societies worldwide. Understanding the underlying physical processes including their transient behaviour and tipping points is indispensable for identifying areas under high risk and to make a key step towards forecasting earthquakes. Numerical modelling can help to interpret observed events in the context of the seismic cycle since state-of-the-art models are able to capture the entire event chain from long-term buildup of tectonic stress and pre-seismic transients over the earthquake itself to post-seismic deformation.
To overcome current limitations of seismic cycle models in terms of spatial and temporal resolution, I am implementing a rate and state friction law in the massively parallelised geodynamic research software ASPECT. By taking advantage of its pre-existing functionalities such as adaptive mesh refinement, adaptive time stepping, and elasto-visco-plastic rheology, I plan to conduct high resolution seismic cycle models in three dimensions. This is an interdisciplinary project that brings together expertise from numerical and analogue models, observational data, and the numerical analysis of partial differential equations.
Project type: Geo.X PhD project
Project duration: 2019-2022
PhD Candidate: Esther Heckenbach
Key publication: Sobolev, S. V., & Muldashev, I. A. (2017). Modeling Seismic Cycles of Great Megathrust Earthquakes Across the Scales With Focus at Postseismic Phase. Geochemistry, Geophysics, Geosystems, 18(12), 4387–4408. https://doi.org/10.1002/2017GC007230
Continental rifting is a fundamental process in plate tectonics, where continental crust is stretched, while faults and fractures initiate and grow. These tectonic faults are responsible for devastating earthquakes in places of active rifting such as Ethiopia and Tanzania. On longer timescales, these faults are critical to the formation of sedimentary basins hosting large quantities of the natural resources. Despite their importance, we still know relatively little about how normal fault networks grow in space and time (Gawthorpe and Leeder, 2000; Cowie et al., 2005; Bell et al., 2014; Ritter et al., 2018; Rotevatn et al., 2018). How do fault networks coalesce and which parameters control this process? Are normal faults growing simultaneously in length and displacement? How much of the total deformation do these faults accommodate?
We will explore these questions by linking geodynamic simulations of continental rifting with seismic observations of rifted continental crust. Recent advances in geodynamic modelling allow us to the run large-scale geodynamic models of continental rifting (Brune et al., 2017) resolving for the first time the 3-D evolution of fault networks. At the same time, new 3-D seismic surveys reveal entire faults systems in rifted continental crust at unprecedented detail (Wrona et al., 2017). Comparing simulations and observations has however been difficult so far, as it involves the interpretation of large volumes of data (GBs to TBs) in complex 3-D fault configurations. This project will employ artificial intelligence in order to overcome this difficulty by extracting key fault properties (e.g. geometry, strain) from both types of data. This is a unique opportunity to isolate the processes governing normal fault network evolution by bridging geodynamic models and seismic observations using cutting edge deep learning techniques.
Project type: Geo.X fellowship
Project duration: 2019-2022
Fellow: Thilo Wrona
Wrona T., Pan I., Bell R.E., Gawthorpe R.L., Fossen H., Brune S. (2020) Deep learning of geological structures in seismic reflecion data. EarthArXiv. https://doi.org/10.31223/X5S88B
Naliboff J.B., Glerum A., Brune S., Peron-Pinvidic G. & Wrona T. (2020) Development of 3‐D Rift Heterogeneity Through Fault Network Evolution. Geophysical Research Letters. https://doi.org/10.1029/2019GL086611
Global and regional climate are profoundly influenced by patterns of ocean circulation, which in turn is modulated by the distribution of continents and seafloor topography. Motions of the continents over millions of years shift and reshape the ocean basins, causing ocean currents to change. Dramatic changes can occur when continents break apart opening ‘seaways’ that control seawater flow between major ocean basins. This project combines plate tectonic reconstructions with 3D lithospheric extension simulations to create high-resolution boundary conditions for paleo-oceanographic circulation models of the Tasman and North Atlantic seaways. We investigate how quickly, and by how much, tectonic processes change the width, depth and latitude of a seaway. The geodynamic evolution may be influenced by long transform boundaries, continental fragments or vertical motions due to mantle plume activity. Subsequently we will provide calculations how the seaway evolution affects oceanographic flow and long-term temperature trends in the oceans.
Project duration: 2018-2021
Funding agency: Australian Research Council
Primary Investigator: Joanne Whittaker (University of Tasmania, Hobart, Australia)
Cooperations: Sascha Brune, Simon Williams(EarthByte Group, University of Sydney), Andreas Klocker (University of Tasmania, Hobart, Australia), Carmen Gaina (University of Oslo, Norway) and David Munday (British Antarctic Survey, UK)
Rifts provide a unique window into the geodynamic system of our planet and the processes that shape the surface of the Earth. The CRYSTALS project aims at a thorough understanding of continental rift dynamics and rifted margin formation by means of a comprehensive multi-scale numerical modelling design. Find out more.
Project type: Helmholtz Young Investigators Group
Time frame: 2016 - 2021
Funding agency: Helmholtz Association
Principal investigator: Sascha Brune
Giacomo Corti (Florence University, Italy)
The Andean foreland basin of Argentina is an ideal area to study the interaction between deep and surface processes, including volcanism and tectonics, climate and erosion/sedimentation, as well as their impact on metallogenesis, hydrocarbon resource generation and fluid migration. Our project aims to model these multi-spatial and multi-temporal processes using geodynamics numerical modelling tools to give a relevant picture for the society. More details: Website
Project type: International Research Training Group IGK2018
Time frame: 2015 - 2021
Funding agency: DFG, German Research Foundation and The federal state of Brandenburg
Principal investigator:Stephan Sobolev
PhD students: (2015-2018) Sibiao Liu, (2018-2021) Michaël Pons
Publications: Ibarra, F., S. Liu, C. Meeßen, C. B. Prezzi, J. Bott, M. Scheck-Wenderoth, S. Sobolev, and M. R. Strecker. ‘3D Data-Derived Lithospheric Structure of the Central Andes and Its Implications for Deformation: Insights from Gravity and Geodynamic Modelling’. Tectonophysics 766 (5 September 2019): 453–68. https://doi.org/10.1016/j.tecto.2019.06.025
Liu, Sibiao. (2020). Controls of foreland-deformation patterns in the orogen-foreland shortening system. Thesis https://doi.org/10.25932/publishup-44573
Subductions zones are main components of plate tectonics and around 90% of the plate driving forces derive from the negative buoyancy of sinking lithosphere in subduction zones. However, despite their vital role, it is still enigmatic how and where subduction zones form. A recently proposed scenario that is independent of any pre-existing weakness zone, is plume-induced subduction initiation, which can explain the beginning of the first sucbduction zone without the help of plate tectonics. However, many key aspects of this new scenario have not been investigated yet. In this project, we answer the following questions by using cutting-edge 3-d numerical models: What is the lithosphere's response to plateau-plume interaction and which processes control lithospheric deformation? What is the impact of regional extension on plume-plateau interaction? Which parameters play key roles for the formation of a single one-sided plume-induced subduction zone (instead of formation of several slabs around the plateau)? We apply our models to the geologically most recent example of plume-induced subduction at the south-western margin of the Caribbean plate, which occurred around 100 million years ago.
Project duration: 2018-2020
Primary Investigator: Sascha Brune
Personnel: Marzieh Baes
Baes, M., Sobolev, S. V., Gerya, T., & Brune, S.(2020). Plume-Induced Subduction Initiation: Single-Slab or Multi-Slab Subduction? Geochemistry Geophysics Geosystems (G3), 21 (2): e2019GC008663. https://doi.org/10.1029/2019GC008663
Many fundamental evolutionary cycles on Earth - including the dispersal of supercontinents and the global carbon cycle - are driven by our planet's dynamic engine, plate tectonics. Geodynamic processes hold important implications for climate science since CO2 is released from Earth’s interior into the atmosphere. In order to link plate tectonics and complex lithospheric deformation to the global carbon cycle we combine plate tectonic reconstruction with numerical carbon cycle simulation. This allows quantifying the tectonic evolution of plate boundaries as well as tectonic CO2 release rates through deep time with profound implications for long-term climate simulations.
Project duration: 2017-2018
Funding Agency: DAAD
Primary Investigator: Sascha Brune
Brune, S., Williams, S.E., and Müller, R.D., 2017, Potential links between continental rifting, CO2 degassing and climate change through time: Nature Geoscience, v. 10, p. 941, doi: 10.1038/s41561-017-0003-6.
RHUM-RUM (Réunion Hotspot and Upper Mantle - Réunions Unterer Mantel) is a French-German passive seismic experiment designed to image a classical oceanic mantle plume – or lack of plume – from crust to core beneath Réunion Island. The results enable insights into the material and heat flow in the Earth's deep interior and provide a geodynamic context for the still controversially debated deep mantle plumes.
Modelling the mantle plume underneath Réunion Island in the Indian Ocean is a valuable contribution to the RHUM-RUM project, because the plume in a geodynamic model can be studied in a dynamic context - in contrast to seismic tomography. The present-day model state can be regarded as a "true" prediction for the dynamics in the Earth's interior und can therefore be compared to the seismic results.
Time frame: 2014 - 2017
Funding: DFG - Deutsche Forschungsgemeinschaft (STE 907/11-1)
Principal Investigators: Dr. Bernhard Steinberger
Personnel: Eva Bredow
Bredow, E., B. Steinberger, R. Gassmöller, and J. Dannberg (2017), How plume-ridge interaction shapes the crustal thickness pattern of the Réunion hotspot track, Geochem. Geophys. Geosyst., 18, 2930–2948, doi:10.1002/2017GC006875.