Search

Rifting and continental break-up is a key research topic within geosciences, and a thorough understanding of the processes involved, as well as of the associated natural hazard and natural resources is of great importance to both science and society. As a result, a large body of knowledge is available in the literature, yet most of previous research focuses on tectonic and geodynamic processes and their links to the evolution of rift systems. However, we believe that the key challenge for researchers is to make our knowledge of rift systems available and applicable to face new societal challenges. In particular, we should embrace a system analysis approach, and aim to apply our knowledge to better understand the links between rift processes, natural hazards, and the geo-resources that are of critical importance to realize the energy transition and a sustainable future. The aim of this paper is therefore to provide a first-order framework for such an approach, by providing an up-to-date summary of rifting processes, hazards, and geo-resources, followed by an assessment of future challenges and opportunities for research. We address the varied terminology used to characterise rifting in the scientific literature, followed by a description of rifting processes with a focus on the impact of (1) rheology and stain rates, (2) inheritance in three dimensions, (3) magmatism, and (4) surface processes. Subsequently, we address the considerable natural hazards and risks that occur in rift settings, which are linked to (I) seismicity, (II) magmatism, and (III) mass wasting, and provide some insights in how the impacts of these hazards can be mitigated. Moreover, we classify and describe the geo-resources occurring in rift environments as (a) non-energy resources, (b) geo-energy resources, (c) water and soils, and (d) opportunities for geological storage. Finally, we discuss the key challenges for the future linked to the aforementioned themes, and identify numerous opportunities for follow-up research and knowledge application. In particular, we see great potential in systematic knowledge transfer and collaboration between researchers, industry partners and government bodies, which may be the key to future successes and advancements. [ABSTRACT FROM AUTHOR]

Rifting and continental break-up is a key research topic within geosciences, and a thorough understanding of the processes involved, as well as of the associated natural hazard and natural resources is of great importance to both science and society. As a result, a large body of knowledge is available in the literature, yet most of previous research focuses on tectonic and geodynamic processes and their links to the evolution of rift systems. However, we believe that the key challenge for researchers is to make our knowledge of rift systems available and applicable to face new societal challenges. In particular, 5 we should embrace a system analysis approach, and aim to apply our knowledge to better understand the links between rift processes, natural hazards, and the geo-resources that are of critical importance to realize the energy transition and a sustainable future. The aim of this paper is therefore to provide a first-order framework for such an approach, by providing an up-to-date summary of rifting processes, hazards, and geo-resources, followed by an assessment of future challenges and opportunities for research. We address the varied terminology used to characterise rifting in the scientific literature, followed by a description of 10 rifting processes with a focus on the impact of (1) rheology and stain rates, (2) inheritance in three dimensions, (3) magmatism, and (4) surface processes. Subsequently, we address the considerable natural hazards and risks that occur in rift settings, which are linked to (I) seismicity, (II) magmatism, and (III) mass wasting, and provide some insights in how the impacts of these hazards can be mitigated. Moreover, we classify and describe the geo-resources occurring in rift environments as (a) non-energy resources, (b) geo-energy resources, (c) water and soils, and (d) opportunities for geological storage. Finally, we discuss the 15 key challenges for the future linked to the aforementioned themes, and identify numerous opportunities for follow-up research and knowledge application. In particular, we see great potential in systematic knowledge transfer and collaboration between researchers, industry partners and government bodies, which may be the key to future successes and advancements. [ABSTRACT FROM AUTHOR]

Shifts in Euler poles are commonly assumed to result from changes in far-field plate driving forces such as slab-pull and mantle convection, but is this always the case? In this study, deep-imaging seismic reflection data reveals a significant compressional event affecting the Tanzania Coastal Basin during the Jurassic-Cretaceous separation of East and West Gondwana. This impressive compressional episode, which resulted in the abandonment of MOR segments, buckle folding of young (< 3 Ma) oceanic crust and the development of a > 250 km long oceanic thrust belt along pre-existing fracture zones, was triggered by a ∼ 30 ̊ rotation of plate motion vectors from NW-SE to N-S. However, no contemporaneous variation in far-field plate driving forces occurred during this plate motion change. Instead, plate kinematic modelling reveals that a contemporaneous N-S alignment of weak rifted margins and young MOR segments, along which the 2000 km Davie Fracture Zone (DFZ) propagated northwards, instigated the rotation. It was therefore not a change in driving forces, but the appearance of an alternative weak (and "preferable") pathway that led to this plate motion change. Interestingly, but not surprisingly, the DFZ was then dominated by transpression subsequent to its development. Although the N-S alignment of weak lithosphere along which it formed was "preferable" to continued NW-SE spreading, for no reason would it be expected to be perfectly oriented with plate driving forces. Plate kinematics during the opening of the Western Somali Basin therefore did not directly reflect the active plate driving forces but were heavily influenced by transform-normal forces and opportunistic plate boundary reconfigurations. We argue that continental transform margins and long-offset oceanic transforms have a significant control on plate motions when under transpression and need to be taken into consideration when inferring mantle processes from plate kinematics. [ABSTRACT FROM AUTHOR]

Significant poly-phase deformation occurs in adjacent continental domains prior to, simultaneously with, and after continental breakup. Constraining this deformation is essential for understanding the regional development and the mechanisms driving and controlling rifting and breakup. Here, we primarily use published constraints to construct deformable plate tectonic models for the East African conjugate margins of Madagascar and Somalia/Kenya/Tanzania using GPlates, an open source plate tectonic modelling environment. The aim of this work is to test both the capability of the GPlates deformable modelling approach and the published model inputs, including time and location of necking zones and earliest oceanic crust. The results demonstrate that inclusion of independent micro-continental fragments (e.g. Comoros microcontinent and the Bur region in Somalia) and locally defined limits of continental crust, generally produce results more akin to observations. The results also allude towards a complex poly-phase progression of rifting that led to the formation of continental fragments surrounding the Western Somali Basin. These deformation episodes are likely linked to changes in plate kinematics and had significant consequences for the age and crustal nature of the Somali margin. Finally, we suggest that the extreme compressional deformation observed offshore Madagascar and Mozambique along the Davie Ridge is also the result of Mesozoic plate motions. [ABSTRACT FROM AUTHOR]