About this Research Topic
Meso- and microscopic structures in rocks are produced by deformation combined with metamorphism and fluid activity. Such structures include folds, boudinage, ductile and brittle shear fabrics in shear zones and faults, and magmatic to solid-state fabrics in plutons. The investigation of such small-scale structures is a fundamental step towards the understanding of complex physico-chemical feedback processes during deformation, with the aim to evaluate crustal-scale structures in terranes and plate boundaries. Based on three-dimensional structural mapping aided by modern techniques like terrestrial laser scanning, unmanned aerial vehicles and structure from motion reconstructions, mesoscopic structures are analyzed in the field to evaluate progressive and polyphasic deformation, and their relationship with changing large-scale tectono-metamorphic processes. Field work is supported by microtectonic studies in the lab, such as optical/digital/scanning electron microscopy, computer tomography and various analytical techniques, which help to understand the nature of dynamic recrystallization, intracrystalline deformation, formation of shape and crystallographic preferred fabrics and the correlation of strain fabric with mineral reactions and growth under changing pressure/temperature/rock-fluid interaction conditions.
Information from micro- and mesoscopic studies is integrated with structural maps in order to understand the large-scale structures of the investigated area. Geophysical data might add important information and help to understand the subsurface structures. Geochronological data is crucial for assessing the timing of magmatism, deformation, fluid-assisted and cooling events, and for understanding the rate of deformation and metamorphic processes.
Major deformation zones are concentrated along plate margins, but also occur in intracontinental settings. Commonly, three tectonic settings have been described, namely, convergent, divergent and strike-slip, though combinations between them are common. There are several structural features which are characteristics of a particular tectonic setting, though overlap occurs in several occasions. By studying small scale structures, interpreting the large-scale structural framework and constraining the timing and rates of deformation, the tectonic setting of a region can be disentangled, an approach that can be applied to Precambrian to Phanerozoic terranes.
Topics to be addressed in this Research Topic include:
• Small scale folds and interpretation of large scale folding pattern;
• Ductile shear zones and interpretation of strain kinematics and vorticity;
• Faults, fault kinematics and paleostress reconstruction, earthquake source properties, rock melting;
• Granite fabric and time of magmatism;
• Correlation between folding, shearing, faulting and granite magmatism;
• Granite geochronology;
• Deformation fabric, PT of metamorphism and fabric growth and geochronology of fabric development;
• Interpretation of tectonic settings.
We expect contributions from researchers covering Precambrian to Phanerozoic terranes; mobile belts, platforms, rifts and transform margins. Outcome of this Research Topic will enhance our understanding on small scale structures in different tectonic settings and their application to interpret the large scale tectonics.
Keywords: Folds, Shear Zone, Faults, Granite Fabric, Metamorphic Fabric, Geochronology, Tectonic Setting
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