TS8.2

It is becoming increasingly apparent that the majority of rifts contain a component of obliquity. As such, a spectrum of obliquity can be recognised from orthogonal rifts through to pure strike-slip tectonics. At one end of the spectrum, continental strike-slip and deep oceanic transform faults form major active plate boundaries and are intrinsic features of plate tectonics. Both types of faults are still poorly known in terms of structure, rheology and deformation. Recent works have shown that fracture zones, supposedly inactive features, can be reactivated and be the site of large earthquakes and deformation. The tectonic and magmatic response of large offset transform faults, particularly, is still largely unknown.
The cause of rift obliquity and transform tectonics has been attributed to a range of driving mechanisms, including: oblique crustal and mantle inheritance, a reduced force required for plastic yielding, changes in far-field forces, asthenospheric dynamics, and grain size changes in the lower crust and mantle. The effects of obliquity on rift and transform evolution are extensive, often leading to unique structural settings dominated by transtensional and transpressional processes. The spatio-temporal overlap of distinctive rifting events (governed by transtensional, transpressional or orthogonal kinematics) can result in strongly segmented 3D rift architectures that may influence subsequent reactivation. Rift obliquity and transforms have been linked to a diverse array of phenomena including: rift and breakup-related magmatism, subduction initiation, supercontinent dispersal, microcontinent cleaving, structural inheritance, relative plate motion, hydrocarbon systems, geothermal energy potential, lithosphere-hydrosphere interaction, and hazardous seismic activity.
In this session, we will explore the formation, evolution, the physical properties, the extinction and reactivation of orthogonal, oblique and transform extensional systems and large deep oceanic transform-fracture systems. We seek contributions that address these topics from all geoscience disciplines using both geological and geophysical data, numerical and analogue modelling, and/or direct rock studies from different settings and natural examples, at all scales. Special emphasis will be given to multidisciplinary studies. We count on abstracts divulging on-going international projects and submissions from early career researchers.

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Convener: Patricia Cadenas MartínezECSECS | Co-conveners: Georgios-Pavlos FarangitakisECSECS, Alexander L. PeaceECSECS, Jordan J. J. PhetheanECSECS, Louise Watremez, João Duarte, Marcia Maia, Christian Hensen
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| Attendance Wed, 06 May, 10:45–12:30 (CEST)

It is becoming increasingly apparent that the majority of rifts contain a component of obliquity. As such, a spectrum of obliquity can be recognised from orthogonal rifts through to pure strike-slip tectonics. At one end of the spectrum, continental strike-slip and deep oceanic transform faults form major active plate boundaries and are intrinsic features of plate tectonics. Both types of faults are still poorly known in terms of structure, rheology and deformation. Recent works have shown that fracture zones, supposedly inactive features, can be reactivated and be the site of large earthquakes and deformation. The tectonic and magmatic response of large offset transform faults, particularly, is still largely unknown.
The cause of rift obliquity and transform tectonics has been attributed to a range of driving mechanisms, including: oblique crustal and mantle inheritance, a reduced force required for plastic yielding, changes in far-field forces, asthenospheric dynamics, and grain size changes in the lower crust and mantle. The effects of obliquity on rift and transform evolution are extensive, often leading to unique structural settings dominated by transtensional and transpressional processes. The spatio-temporal overlap of distinctive rifting events (governed by transtensional, transpressional or orthogonal kinematics) can result in strongly segmented 3D rift architectures that may influence subsequent reactivation. Rift obliquity and transforms have been linked to a diverse array of phenomena including: rift and breakup-related magmatism, subduction initiation, supercontinent dispersal, microcontinent cleaving, structural inheritance, relative plate motion, hydrocarbon systems, geothermal energy potential, lithosphere-hydrosphere interaction, and hazardous seismic activity.
In this session, we will explore the formation, evolution, the physical properties, the extinction and reactivation of orthogonal, oblique and transform extensional systems and large deep oceanic transform-fracture systems. We seek contributions that address these topics from all geoscience disciplines using both geological and geophysical data, numerical and analogue modelling, and/or direct rock studies from different settings and natural examples, at all scales. Special emphasis will be given to multidisciplinary studies. We count on abstracts divulging on-going international projects and submissions from early career researchers.

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