TS1 – General themes in Tectonics and Structural Geology
Permo-Triassic geodynamics at the Gondwana-Laurasia boundary: interplay between magmatism and tectonics
The Gondwana-Laurasia boundary was subjected to a complex geodynamic evolution between Late Paleozoic and Early Mesozoic, typified by multiple magmatic cycles developed under different tectonic and thermal regimes. A variety of mantle sources was involved in these tectonic, magmatic and metamorphic events, which induced significant modifications of the continental crust.
In the last decade, detailed studies in petrology, tectonics and stratigraphy have contributed on shedding light on the articulated evolution of this area, stimulating an intense debate about the overall Permo-Triassic geodynamic framework.
A multidisciplinary session is proposed to assess and discuss the recent advancements that contribute to draw an accurate geodynamic picture of this pivotal sector of the Pangea realm in the time span between the Variscan orogeny and the Late Triassic onset of rifting in the Central Atlantic-Alpine Tethys domain. Researches from a broad range of disciplines, such as (but not limited to) petrology/geochemistry, tectonics, geochronology, stratigraphy and basin analysis, are welcome.
Deformation microstructures (e.g. fabrics, textures, grain sizes, shapes, cracks etc) give insight into the conditions and processes of brittle failure and ductile flow of geomaterials. Microstructures and textures are a key tool in unraveling deformation histories and processes, kinematics and conditions in deformed rocks or ice. Processes such as grain-size reduction, phase changes, and development of crystallographic preferred orientations modify the rheological, elastic, and thermal properties of these rocks, providing key information on the evolution and dynamics of the litho- and cryosphere. In this session, we invite contributions based on microstructure and texture analysis from field observations, laboratory experiments, and numerical modelling that aim to constrain deformation mechanisms, physical and mechanical properties of geomaterials using well established or novel techniques.
From the nano- to the orogen-scale: metamorphism, deformation and fluid-rock interaction
Investigation of rock-forming processes in the Earth’s crust and mantle spans from the nano- to the orogen-scale and encompasses diverse techniques and approaches, including but not limited to field-based studies, petro-geochemical analysis and petrological and geodynamic modelling. All our observations in the rock record are the end-product of metamorphism, metasomatism, and deformation events that occurred during a terrane’s geological evolution. The study of metamorphic rocks is thus the key to decipher large scale and long-lasting tectonic processes, such as crustal thickening and exhumation, or the composition of geologic fluids and their role in geochemical cycling and deformation. Furthermore, reactions between fluids and rocks have a fundamental impact on many of the natural processes occurring in crustal settings, i.e. metamorphism and associated rheological weakening, localization of deformation, earthquake nucleation caused by high pressure fluid pulses and metasomatic fronts.
This session will focus on novel approaches to address key geological questions at a wide range of temporal and spatial scales using a multidisciplinary approach combining field, structural, petrological, geochemical techniques and thermodynamic simulations.
Long-term rheology , heat budget and dynamic permeability of deforming and reacting rocks: from laboratory to geological scales
The goal of this session is to reconcile short-time/small-scale and long-time/large-scale observations, including geodynamic processes such as subduction, collision, rifting or mantle lithosphere interactions. Despite the remarkable advances in experimental rock mechanics, the implications of rock-mechanics data for large temporal and spatial scale tectonic processes are still not straightforward, since the latter are strongly controlled by local lithological stratification of the lithosphere, its thermal structure, fluid content, tectonic heritage, metamorphic reactions and deformation rates.
Mineral reactions have mechanical effects that may result in the development of pressure variations and thus are critical for interpreting microstructural and mineral composition observations. Such effects may fundamentally influence element transport properties and rheological behavior.
Here, we encourage presentations focused on the interplay between metamorphic processes and deformation on all scales, on the rheological behavior of crustal and mantle rocks and time scales of metamorphic reactions in order to discuss
(1) how and when up to GPa-level differential stress and pressure variations can be built and maintained at geological timescales and modelling of such systems,
(2) deviations from lithostatic pressure during metamorphism: fact or fiction?,
(3) the impact of deviations from lithostatic pressure on geodynamic reconstructions.
(4) the effect of porous fluid and partial melting on the long-term strength.
We therefore invite the researchers from different domains (rock mechanics, petrographic observations, geodynamic and thermo-mechanical modelling) to share their views on the way forward for improving our knowledge of the long-term rheology and chemo-thermo-mechanical behavior of the lithosphere and mantle.
Faults and fractures in rocks : mechanics, occurrence, dating, stress history and fluid flow
Fractures and faults are common tectonic features within shallowly deformed rocks. Fracture networks play a fundamental role in fluid migration. Understanding the mechanical and chronological development of fracture networks is therefore key for tectonic studies as well as for resources exploration and waste repositories studies.
This session aims at bringing together scientists working in the field, in the lab, and on simulations to foster discussion towards improving our understanding of (1) the mechanics, occurrence, timing and stress history of fractures in upper crustal rocks, and (2) the role fracture networks play on subsurface fluid flow. We welcome contributions from all fields, including structural geology, mechanics, isotope geochemistry, and hydrogeology that aim at comprehending the development of fracture systems in time and space and their co-evolution with fluid flow in a variety of geological settings.
Late-Breaking Session: The December 2020 earthquake sequence in Petrinja, Croatia, and its seismotectonic and geodynamic environments
On 29 December 2020, a major earthquake (Mw 6.4) occurred in Croatia close to Petrinja, only nine months after another Mw 5.5 damaging earthquake in Zagreb, the capital city located 45 km north of Petrinja. The December shock is the strongest event in continental Europe since the Norcia sequence (Italy) in 2016 and was caused by the rupture of a NW-SE dextral strike-slip fault at the boundary between the Dinarides and the Pannonian basin ; it was preceded by two strong foreshocks (M~5) the day before. Seismic shaking was widely felt across Europe, and caused extensive damage to buildings and infrastructures in the epicentral region. The earthquake resulted in liquefaction over large areas, and many cracks and a surface rupture have been observed in the field.
This late-breaking session aims at gathering contributions to discuss the 2020 Petrinja earthquake sequence, its surface effects on human and natural environment in terms of shaking and faulting. We encourage presentations dealing with the seismological, geodetical or geological observations related to this earthquake and the ongoing seismic sequence, as well as insights on the regional faults, their historical seismicity or recent geological activity. All this together can help in understanding the geodynamics of this seismically active but poorly characterized region.
The Mechanics of Earthquake Faulting: a multiscale approach
Earthquake mechanics is controlled by a spectrum of processes covering a wide range of length scales, from tens of kilometres down to few nanometres. While the geometry of the fault/fracture network and its physical properties control the global stress distribution and the propagation/arrest of the seismic rupture, earthquake nucleation and fault weakening is governed by frictional processes occurring within extremely localized sub-planar slipping zones. The co-seismic rheology of the slipping zones themselves depends on deformation mechanisms and dissipative processes active at the scale of the grain or asperity. The study of such complex multiscale systems requires an interdisciplinary approach spanning from structural geology to seismology, geophysics, petrology, rupture modelling and experimental rock deformation. In this session we aim to convene contributions dealing with different aspects of earthquake mechanics at various depths and scales such as:
· the thermo-hydro-mechanical processes associated with co-seismic fault weakening based on rock deformation experiments, numerical simulations and microstructural studies of fault rocks;
· the study of natural and experimental fault rocks to investigate the nucleation mechanisms of intermediate and deep earthquakes in comparison to their shallow counterparts;
· the elastic, frictional and transport properties of fault rocks from the field (geophysical and hydrogeological data) to the laboratory scale (petrophysical and rock deformation studies);
· the internal architecture of seismogenic fault zones from field structural survey and geophysical investigations;
· the modeling of earthquake ruptures, off-fault dynamic stress fields and long-term mechanical evolution of realistic fault networks;
· the earthquake source energy budget and partitioning between fracture, friction and elastic wave radiation from seismological, theoretical and field observations.
· the interplay between fault geometry and earthquake rupture characteristics from seismological, geodetic, remote sensed or field observations;
We particularly welcome novel observations or innovative approaches to the study of earthquake faulting. Contributions from early career scientists are solicited.
Seismic and aseismic deformation at seismogenic faults: from distributed to localized deformation
Tectonic plate motion is accommodated through aseismic and seismic slip on faults, visco-elastic processes, and permanent plastic deformation. These processes control the stress redistribution throughout the Earth’s crust at all spatio-temporal scales, from localized earthquakes to long-term and -wavelength viscous interaction. The contribution of other factors, such as fluids, also play an important role in the mechanism of such processes. Understanding the physics and the energy partitioning between these processes at all scales and in various tectonic settings is essential to assess their impact on the seismic cycle. To improve our comprehension in the partitioning between seismic-aseismic slip and brittle-ductile deformation at all scales, we invite contributions that explore the themes described herein, through geophysical and geological observations, laboratory experiments, numerical modelling, and the integration of multiple approaches.
Linking active faults and the earthquake cycle to Seismic Hazard Assessment: Onshore and Offshore Perspectives
Recent developments in understanding of faulting and the earthquake cycle are improving our approaches to seismic hazard assessment. These developments are due to the increasing availability of datasets, including remote sensing, geochemical, offshore geophysics, boreholes and numerical modelling, and have been applied to both onshore and offshore faults which contribute to seismic hazard. From these datasets and developments, it is clear that there is more variability in the earthquake cycle and the seismogenic potential of faults than previously accounted for in seismic hazard assessment. This session will explore a range of datasets and study locations and discuss how they can be applied to different aspect of seismic hazard assessment.
Active Tectonics and Geodynamics of Eastern Mediterranean
The broad scale tectonics of the Eastern Mediterranean is dominated by the interaction of the Nubian and Arabian plates with the Eurasian plate. This complex tectonic frame exhibits almost all types of plate boundary conditions such as continental collision and extension, oceanic subduction, and continental transform. The evolution and present deformation are constrained by diverse geological, geophysical, and geodetic observations and have been explained by different hypotheses, such as (a) tectonic escape system caused by the post-collisional convergence of Eurasian and Arabian plates creating forces at its boundaries with gravitational potential differences of the Anatolian high plateau (b) asthenospheric flow dragging the circular flow of lithosphere from the Levant to Anatolia in the east and the Aegean in the west, (c) slab pull of the Hellenic subduction, (d) mantle upwelling underneath Afar and with the large-scale flow associated with a whole mantle, Tethyan convection cell, (e) or combinations of these mechanisms for the Eastern Mediterranean. Naturally, this tectonic setting generates frequent earthquakes with large magnitudes (M > 7), forming a natural laboratory on understanding the crustal deformation, and crust-mantle interactions for various disciplines of active tectonics.
Multidisciplinary studies, especially within the last three decades, have made significant contributions to our understanding of the processes on the crustal deformation, and interaction of the mantle with the crustal processes of this region. With this session, we aim to bring together the recent findings of these studies, thus we welcome/invite contributions from a wide range of disciplines including, but not limited to, neotectonics, seismology, tectonic geodesy (e.g. GNSS, InSAR), palaeoseismology, tectonic geomorphology, remote sensing, structural geology and geodynamic modelling, which geographically cover the Eastern Mediterranean region, including Anatolia-Aegean Block, Caucasus, Iran, Middle East and Greece.
Earthquake swarms and complex seismic sequences driven by transient forcing in tectonic and volcanic regions
Earthquake swarms are characterized by a complex temporal evolution and a delayed occurrence of the largest magnitude event. In addition, seismicity often manifests with intense foreshock activity or develops in more complex sequences where doublets or triplets of large comparable magnitude earthquakes occur. The difference between earthquake swarms and these complex sequences is subtle and usually flagged as such only a posteriori. This complexity derives from aseismic transient forcing acting on top of the long-term tectonic loading: pressurization of crustal fluids, slow-slip and creeping events, and at volcanoes, magmatic processes (i.e. dike and sill intrusions or magma degassing). From an observational standpoint, these complex sequences in volcanic and tectonic regions share many similarities: seismicity rate fluctuations, earthquakes migration, and activation of large seismogenic volume despite the usual small seismic moment released. The underlying mechanisms are local increases of the pore-pressure, loading/stressing rate due to aseismic processes (creeping, slow slip events), magma-induced stress changes, earthquake-earthquake interaction via static stress transfer or a combination of those. Yet, the physics behind such processes and the ultimate reasons for the occurrence of swarm-like rather than mainshock-aftershocks sequences, is still far beyond a full understanding.
This session aims at putting together studies of swarms and complex seismic sequences driven by aseismic transients in order to enhance our insights on the physics of such processes. Contributions focusing on the characterization of these sequences in terms of spatial and temporal evolution, scaling properties, and insight on the triggering physical processes are welcome. Multidisciplinary studies using observation complementary to seismological data, such as fluid geochemistry, deformation, and geology are also welcome, as well as laboratory and numerical modeling simulating the mechanical condition yielding to swarm-like and complex seismic sequences.
Rift basin evolution: Interplay between tectonic deformation and surface processes
Sedimentary basins within rifts are characterised by complex, dynamic environments, with the interplay between tectonic deformation, surface processes and climate controlling basin architecture and sedimentary infill. Ongoing research elucidates the links between these factors, permitting improved understanding of basin evolution and subsequent facies distribution, with implications for resource exploration.
This session aims to bring together researchers from various backgrounds in order to foster collaboration. We invite contributions that investigate the relationships between, and interaction of, rift tectonics, surface processes and climate, at a variety of spatial and temporal scales. We welcome approaches including remote-sensing analysis, geophysical methods and sedimentological, structural or geomorphological fieldwork. Analogue and numerical modelling methods are also encouraged.
Special issue announcement:
This vEGU21 session has inspired the initiation of a special issue on "Links between tectonics, fault evolution and surface processes in extensional systems", in the gold open access journal Frontiers in Earth Science. The special issue is edited by Frank Zwaan, Alex Hughes, Laura Gregory, Joanna Faure Walker and Lisa McNeill. The call for submission is open and will close on the 31st of October 2021. If you are interested in contributing a paper, please contact us and/or register on the special issue website: https://www.frontiersin.org/research-topics/20047
Studying tectonic and volcanic active areas by geomorphological observations and data collection on high-resolution models, and numerical simulations of tectonic and gravity driven processes
Tectonically and volcanically active areas are subject to faulting, fracturing, volcanic eruptions, caldera or flank collapse, and magmatic intrusions, such as dyking. These events trigger typical geomorphological features and geomorphological changes that researchers can study in the field and remotely. Satellite data using optical or thermal sensors, and ship acoustics datasets, provide first order information about faulting and volcanic activity, however, there is a resolution gap below the meter-scale, critical to detect and to analyse small structures over broad areas and to better assess how faults, magma intrusions and collapses nucleate and evolve. Moreover, during large metrical ground deformations (earthquakes, dyke intrusions, collapses), the near-field area where satellite radar signal (InSAR) becomes incoherent remains poorly studied, likewise happens in deep sea environments using vessel-based acoustics techniques. In addition, classical field surveys and data collection are, very often, not feasible due to difficult logistic conditions and/or inaccessible areas. Therefore, there is a need to collect higher resolution data to better understand geomorphologic, faulting and volcanic processes at scales from cm to a few meters, that complement classical field studies and remote sensing data.
Structure-from-Motion (SfM) photogrammetry techniques have been applied using imagery acquired from field, aerial and underwater survey, using Unmanned Aerial Vehicles (UAVs, i.e. drones), Remotely Operated Vehicles (ROVs), Autonomous Underwater Vehicles (AUVs), balloons, airplanes and helicopters, as well as cameras and mobile phones. This technique produces digital surface models (DSM), ortho-mosaic imagery, dense point clouds and 3-D models, creating a high-resolution environment reconstruction for local outcrops or broader areas.
The session will focus on the application of SfM for research in the field of structural geology, active tectonics, volcano-tectonics, and geomorphology, with particular regard to tectonically and volcanically active areas. The session covers the following topics: i) case studies where the SfM has been employed; ii) SfM methods, 3-D reconstruction and post-processing analysis; iii) integration and comparison of SfM-derived, field and broad-scale data (such as satellites and acoustics techniques); iv) new tools and methods for data analysis on SfM-derived models; and vi) future works and applications of SfM techniques.
Investigating deep-Earth dynamics through time and space using surface observations.
Geomorphic and geologic observations at the Earth's surface reflect the combined effects of erosional, tectonic, and deep-seated processes. Such surface observations therefore provide important constraints on mantle convection patterns and subduction dynamics through space and time, which compliment both studies of geophysical data and numerical simulation. However, using Earth's surface records to constrain deep-seated processes is complicated by (1) our as yet incomplete understanding of how mantle convection or subduction processes are manifest as surface forms and patterns, and (2) the effects of tectonic processes, spatio-temporal variations in climate, glacial isostatic adjustment, lithology, biota, and human alteration of landscapes and surface geology. We invite contributions that tackle these challenges and work toward identifying the surface expression of deep-Earth processes such as mantle convection, in different tectonic settings. We welcome studies that develop and apply a variety of approaches across temporal and spatial scales, including (but not limited to) geomorphic analysis, geophysics, thermochronometry, isotope and cosmogenic nuclide measurements, and numerical and analogue modeling of both surface and deep-Earth dynamics. We hope that this session will provide opportunities for presenters from all backgrounds, demographics, and all stages of their scientific career to engage in this exciting and emerging geological problem via a multidisciplinary approach.
Interactions between tectonics, climate and surface processes from mountain belts to basins
The coupling between tectonics, climate and surface processes governs the dynamics of mountain belts and basins. First order constraints on this coupling are provided by geomorphic and sedimentary records, including longitudinal river profiles, fluvial terraces, downstream fining trends, growth strata, sediment provenance, sequence stratigraphy, and changing depositional environments. Moreover, the increasing integration of geochronological methods for quantifying erosion rates and source-to-sink sediment transfer with landscape evolution, stratigraphic, climatic, and tectonic models allows to advance our understanding of the interactions between surface processes, climate and tectonic deformation.
We invite contributions that use geomorphic and/or sedimentary records to understand tectonic deformation, climate histories, and surface processes, and welcome studies that address their interactions and couplings at a range of spatial and temporal scales. In particular, we encourage coupled catchment-basin studies that take advantage of numerical/physical modelling, geochemical tools for quantifying rates of surface processes (cosmogenic nuclides, low-temperature thermochronology, luminescence dating) and high resolution digital topographic and subsurface data. We also encourage field or subsurface structural and geomorphic studies of landscape evolution, sedimentary patterns and provenance in deformed settings, and invite contributions that address the role of surface processes in modulating rates of deformation and tectonic style, or of tectonics modulating the response of landscapes to climate change.
Continental Rift Evolution: from inception to break-up, with special attention to the The Afro-Arabian rifting system
Continental rifting is a complex process spanning from the inception of extension to continental rupture or the formation of a failed rift. This session aims at combining new data, concepts and techniques elucidating the structure and dynamics of rifts and rifted margins. We invite submissions highlighting the time-dependent evolution of processes such as: initiation and growth of faults and ductile shear zones, tectonic and sedimentary history, magma migration, storage and volcanism, lithospheric necking and rift strength loss, influence of the pre-rift lithospheric structure, rift kinematics and plate motion, mantle flow and dynamic topography, as well as break-up and the transition to sea-floor spreading.
We encourage contributions using multi-disciplinary and innovative methods from field geology, geochronology, geochemistry, petrology, seismology, geodesy, marine geophysics, plate reconstruction, or numerical or analogue modelling. Especially welcome are presentations that provide an integrated picture by combining results from active rifts, passive margins, failed rift arms or by bridging the temporal and spatial scales associated with rifting.
Withing this session, a specific segment will be dedicated to studies of rift tectonics in the The Afro-Arabian rift system (the basins of the Gulf of Suez, Gulf of Aqaba, Red Sea, Gulf of Aden, Afar depression and the surrounding regions or related areas). This system contains the world’s largest active continental rift and is the key locality for studying continental breakup processes. Natural phenomena such as basin formation, continental breakup, seismic and volcanic activity, and the formation of mineral resources in and around the three arms of the Afar triple junction highlights some of the key aspects of this complex rift system.
Special issue alert:
This session is linked to three special issues in the gold open access journal "Frontiers in Earth Science".
(1) "Links between tectonics, fault evolution and surface processes in extensional systems", edited by Frank Zwaan, Alex Hughes, Laura Gregory, Joanna Faure Walker and Lisa McNeill. Manuscript submission deadline: 31 October 2021. Link: https://www.frontiersin.org/research-topics/20047
(2) "InSAR for Volcanoes and Tectonics", edited by Carolina Pagli, Hua Wang, Anne Socquet and Vincent Drouin. Manuscript submission deadline: 30 June 2021. Link: https://www.frontiersin.org/research-topics/18940
(3) "Geodynamics and Magmatism in the Afro-Arabian Rift System", edited by Nico Augustin, Froukje van der Zwan, Joël Ruch, Neil Mitchell, Daniele Trippanera. Manuscript submission deadline: 10 May 2021. Link: https://www.frontiersin.org/research-topics/16355
If you are interested in contributing a paper to one of these special issue, please contact us and/or register on the respective special issue website
Dynamics and structural evolution of fold-and-thrust belts: From nature to models across spatial and temporal scales
Fold-and-thrust belts are one of the most recognizable large-scale geological features occurring all around the globe. Fold-and-thrust belts mostly develop along convergent plate boundaries but they may also form along passive margins or other super-critical slopes driven by a gravitationally driven stress field. Fold-and-thrust belts may involve the basement of continental lithospheres to build entire mountain ranges or just the uppermost sedimentary sequence detaching along stratigraphic décollements. Although these different types of fold-and-thrust belts vary in spatial extent, longevity of their formation, and rock types involved, their dynamics and structural evolution strongly depends on the same internal and external effects, such as rheological and rock mechanical properties, temperature and surface processes, allowing to compare them with each other and to develop common mechanical predictions.
Fold-and-thrust belts have been intensely investigated to decipher their short- and long-term evolution. However, there are important questions that yet have to be fully understood: i) What is the effect of inherited structures within the basement, the cover sequence and potential décollement layers, and how can those inheritances be detected? ii) How are transient and long-term rheological/mechanical characteristics comparable during the formation of a fold-and-thrust belt? iii) Do present day fold-and-thrust belts reflect local, transient conditions, and how are large-scale, long-term tectonic processes affecting their evolution?
The here proposed session tackles to answer these questions by an interdisciplinary approach. We look forward to receive abstracts focusing on the short- and long-term dynamics and structural evolution of fold-and-thrust belts by means of structural fieldwork, seismics and seismology, analogue and numerical modelling, rock mechanics, geomorphology and thermochronology as well as quantification of uncertainties in order to improve our understanding of fold-and-thrust belts across spatial and temporal scales.
Subduction zones evolution and slip styles: advances from tectonics, metamorphism and rheology
Subduction zones are one of the key players in driving plate tectonics. They are the loci of major mineral and rock transformation and deformation, mass/fluid transfer and seismicity, with the subduction thrust interface hosting a range of fault slip styles varying in slip speeds from steady creep to hazardous earthquakes. Understanding initiation and development of present-day and fossil subduction zones, in both space and time, is therefore essential for understanding plate tectonics and, more generally, how the solid Earth system operates. In addition, a better understanding of the structural and mechanical features of the plate interface is of societal importance for estimating the potential seismic and tsunami hazard.
This session aims at better understanding the nature and duration of the tectonic and metamorphic processes controlling the development of subduction zones from the initiation to the mature state. This includes studies focusing on relations between kinematic of plate motions and formation of new subduction zones, mechanisms driving subduction long-term dynamics along the plate interface (e.g., mechanical (de)coupling, strain localisation, rock accretion and exhumation, degree of heterogeneity and viscosity contrast in the material involved, presence and distribution of fluids), as well as those occurring intra-slab or within the accretionary wedge. This session also aims at highlighting the importance of the existing interactions between metamorphism processes and deformation (from nano to km scale) and on their consequences on subduction dynamics and mechanics. We welcome contributions from a wide range of disciplines such as structural geology, tectonics, petrology, geophysics, experimental deformation and numerical modelling, with particular emphasis on the rock record.
Effects of tectonics and surface processes interactions on the evolution of orogenic plateaus and active orogens
Theme A- Orogenic plateaus and plateau margins
Orogenic plateaus and their margins are integral parts of modern mountain ranges and offer unique opportunities to study feedbacks between tectonics and climate at the Earth’s surface. Complex interactions among a wide range of parameters may lead to rapid shifts in surface elevation and the growth, recycling, and destruction of lithosphere. These controlling factors, which include crustal deformation and basin growth, surface uplift and atmospheric circulation, precipitation and erosion, landscape and biological change, result in lateral plateau growth and its characteristic morpho-climatic domains: humid, high-relief margins that contrast with (semi-)arid, low-relief plateau interiors.
Theme B- Bridging records of tectonic and climatic forcings on the evolution of Central Asia: from Paleozoic origins to Cenozoic aridification
Central Asia witnessed profound changes in tectonic and climatic environments over its geologic past: Paleozoic to Mesozoic closures of deep oceans and the amalgamation of major tectonic blocks laying the groundwork for Cenozoic fault reactivations since the India/Asia collision. The Cenozoic rise of intracontinental mountain ranges such as the Tianshan was accompanied by the retreat of Paratethys and the onset of intracontinental aridification. Major efforts bridging tectonic, geomorphic and climatic records are underway to understand i) the tectonic origins of Central Asia and how these control its present-day landscape, ii) individual responses to climatic and tectonic forcings, and their contribution to erosion and sediment deposition patterns, iii) long-term interactions between climatic change and tectonic activity, iv) and the role of topographic barriers, inland seas and global climate change in shaping regional climate and the aridification of the continental interior.
The two primary goals of this session are: 1) creating a discussion forum on the complex interactions and feedbacks among climatic, surficial, and geodynamic processes that challenge the notion of comprehensive mechanisms for the formation of orogenic plateaus and their margins, as well as for the evolution of Central Asia since the Paleozoic; and 2) encouraging future collaborations that not only overcome spatio-temporal scales but also bridge observations across disciplines leading to a more holistic view of landscape evolution from an integrative tectonic, climatic and geomorphic perspective.
Central Asian Tectonics - Pamir, Tian Shan and Tibet from Paleozoic to Present
The mountain ranges of the Pamir, Tian Shan, and the Himalaya-Tibetan orogen form the most prominent morphological features in central Asia. Much of this morphology results from uplift related to the Cenozoic India-Asia collision. However, this is built upon a complex pre-Cenozoic history of ocean closures (Proto- and Paleo-Tethys, Paleo-Asian), terrane accretions and the related reorganization of Asia's southern margin. This long-lasting history of consecutive accretionary events left behind a complex mosaic of high- and low-strain domains, magmatic arcs, allochthonous blocks (terranes) and intervening suture zones. A significant challenge is to correlate and date those domains, which are often used as large-scale structural markers for quantifying large structural offsets. Quantifying pre-collisional topography and crustal thickness is crucial. Both the pre-Cenozoic history and the timing and kinematics of young deformation must be well-constrained in order to reconstruct the orogenic evolution in time and space and to understand how pre-existing structures influenced Cenozoic deformation. To promote discussion on this topic, we invite contributions from geoscientists who are working on various aspects of the geologic evolution of Central Asia, including structural geology, geochemistry, sedimentology, detrital studies, as well as geophysical or modeling studies.
The Alps and neighbouring mountain belts (Pyrenees, Apennines, Dinarides, Carpathians): a multidisciplinary vision (AlpArray)
The Alps have been intensively studied by geologists for more than a century, providing a unique natural laboratory to deepen our understanding of orogenic processes and their relationship to mantle dynamics. Although most concepts that underlie current studies of mountain belts and convergence dynamics were born in the Alps, the belt is now being examined with renewed vigour in the AlpArray project. This project involves a large number of European institutions, with efforts focused on the AlpArray Seismic Network to provide homogeneous seismological coverage of the greater Alpine area at unprecedented aperture and station density, both on land and sea. New data is being recorded in a multidisciplinary research effort, and other projects are being planned in the immediate and mid-term future.
Within this context, we invite contributions from the Earth Science community that highlight new results in AlpArray and similar projects and that identify and solve key open questions of the present and past structure and dynamics of the Alps and neighbouring orogens. Both disciplinary and multi-disciplinary contributions are welcome from geophysical imaging, (seismo)tectonics, structural geology, gravimetry, geodesy, geodynamics, petrology, geochronology and other allied fields, combined with various modelling approaches. Scales of interest range from crustal to upper mantle, in the Alps and neighbouring mountain belts such as the Pyrenees, the Apennines, the Carpathians and the Dinarides.
(Session co-hosted by ILP Task Force CoLiBrI)
Inheritance control on plate boundaries, and inheritance, structures, and kinematics of the Apennines
Tectonic plate boundaries are constantly (re)used to assemble and breakup supercontinents through geological time. This is known as the Wilson Cycle, a concept that describes how sutures and mountains are reactivated to open oceanic basins, which are in turn subducted leading to continental collision and the rise of orogenic belts. The successive rifting and shortening events modify the lithosphere along plate boundaries with structural, compositional, and thermal heterogeneities. In each tectonic event, these inherited heterogeneities are considered to play a key role in localizing strain, defining the structural style, the magmatic budget, and the final architecture of the crust. Thus, elucidating the structural and rheological nature of the heterogeneities and how they interact with far-field tectonic forces to localize deformation remains a key component of interpreting both active and prior deformation patterns.
In the session we welcome contributions that use field observations, geophysical data, analogue and/numerical modelling to investigate all aspects of inheritance and how it controls the tectonic processes involved in shaping convergent and divergent plate boundaries.
The evolution of the Apennines is framed between the fragmentation of Pangea, the development of the Mesozoic Ligurian Tethys, Alpine collisional and the development of the Central Mediterranean Tertiary basins. In this session, we aim to discuss: (a) the sedimentary evolution, from Permian to Present, and its relation with tectonics; deformation and metamorphism developed in the different tectonic environments, from rifting to subduction, exhumation and late-orogenic stages; (b) the role and evolution of the Mesozoic carbonate platform in the Apennines, Alps and Maghrebides; (c) the role of the Sardina-Corsica and Calabria-Peloritan arc to unravel the collisional puzzle in the central mediterranean area and the link between the Alps-Apennines-Magrebides; (d) magmatism in space and time and its connection with the geodynamic evolution, from the orogens to Tertiary extension; (e) processes forming geological resources, from oil to ore deposits and geothermal fields; (f) recent tectonics, as reconstructed through seismological and paleo-seismological studies; (g) the crustal structure, as derived by geophysical methods and their interpretation.
A trans-disciplinary view of the Tethyan realm through space and time: subduction and collisional zones from the Mediterranean to southeast Asia
The Tethyan orogenic belt is one of the largest and most prominent collisional zones on Earth. The belt ranges from the Mediterranean in the west to Papua New Guinea in the east. It results from the subduction and closure of multiple basins of the Tethys Ocean and the subsequent collision of the African, Arabian and Indian continental plates with Eurasia. Its long-lasting geological record of the opening and closure of oceanic basins, the accretion of arcs and microcontinents, the complex interactions of major and smaller plates, and the presence of subduction zones at different evolutionary stages, has progressively grown as a comprehensive test site to investigate fundamental plate tectonics and geodynamic processes with multiple disciplines. Advances in a variety of fields provide a rich and growing set of constraints on the crust-lithosphere and mantle structure and their physical and chemical characteristics, as well as the tectonics and geodynamic evolution of the Tethyan orogenic belt.
We welcome contributions presenting new insights and observations derived from different perspectives, including geology (tectonics, stratigraphy, petrology, geochronology, geochemistry, and geomorphology), geophysics (seismicity, seismic imaging, seismic anisotropy, gravity), geodesy (GPS, InSAR), modelling (numerical and analogue), natural hazards (earthquakes, volcanism). In particular, we encourage the submission of trans-disciplinary studies, which integrate observations across a range of spatial and temporal scales to further our understanding of plate tectonics as a planetary process of fundamental importance.
The Caledonian orogen of the North Atlantic region: a natural laboratory for studying tectonic processes
The Caledonian mountain belt represents a world-class example of a deeply denudated Himalayan-style orogen. The exposed crustal sections allow the study of all stages of the Wilson cycle and may contribute to our understanding of many fundamental processes in Earth Sciences, including (1) continental-rifting, break-up and ocean formation, (2) subduction, (3) marginal basin formation, (4) arc-continent and continental collisions, (5) (U)HP metamorphism, (6) orogenic wedge formation and dynamics, (7) the formation and evolution of crustal-scale shear zones, (8) fluid-rock interactions, (9) ductile and brittle deformation mechanisms, and (10) the dynamics of late- to post-orogenic extension and deep crustal exhumation.
This session aims to bring together scientists studying rocks and geological processes from all stages of the Caledonian Wilson cycle, i.e. from rifting to collision and post-orogenic extension, and welcomes sedimentological, petrological, geochemical, geochronological, geophysical, structural, and modelling contributions that help to improve our understanding of the Caledonides and mountain belts in general.
Metamorphic minerals: the building blocks of geological paradigms
Metamorphic minerals are silent witnesses to tectonic processes, and their changes through geological time. New approaches in chemical and isotope micro-analysis, geochronology provide exciting new avenues to make these minerals 'talk'—to read their record of deformation, reaction and fluid flow, and use it to study our dynamic lithosphere. The insights obtained through such research provide ways to examine the foundations of long-standing concepts in petrology and tectonics, as well as challenge and shift paradigms in these fields.
This session will highlight integrated metamorphic petrology, with application to tectonics and development of collisional orogens, cratons and subduction zones. We welcome contributions, from petrology, (petro-)chronology, to trace-element and isotope geochemistry. Through these diverse insights, the session will provide an exciting overview of current research on metamorphic and metasomatic processes, as well as the avenues for future innovation.
Many new high quality and high resolution geophysical and geological data had been acquired in the past years that need to be updated, re-analysed and re-interpreted in the light of our present knowledge of the subductions processes. Moreover it is needed to better clarify the temporal and spatial evolution of those processes in order to much precise our geodynamic ideas of mountain building, sedimentary basins formation, subduction, the transition from oceanic to continental subductions (collision) or the reverse from collision to subduction...
Among other global places, the zone from Japan, Taiwan to the Philippines is a key area to study such subduction/collision transition due to the rapid convergence between Eurasian and Philippine Sea plates. There are geodynamic inversion of the east dipping Manila oceanic subduction, that evolves northward, first, into a Continental Subduction (so called collision) onshore Taiwan, then secondly, east of Taiwan, into the north dipping Ryukyu arc/continent subduction. Due to the so rapid Plates shortening rate (10cm.y-1), those active Oceanic to Continental Subductions processes in Taiwan creates 1/8 of the annual seismicity in the World !
There are other places in the World active or not, that should also be taken into careful consideration in order to reveal and lead us to better understand new tectonic processes (e.g.: Alpes, Pyrénées, Cascades and so on).
In this EGU session, we aim to discuss and update the existing geodynamic processes and state of the art of the oceanic to continental subductions processes after so numerous data that had been collected recently and all the works that had been done on this subject. Therefore this EGU Session should help us to much better understand the geodynamic of plate convergence, the role of oceanic crust and the transition between subduction and collision.
Analogue and numerical modelling of tectonic processes
Geologic processes are generally too slow, too rare, or too deep to be observed in-situ and to be monitored with a resolution high enough to understand their dynamics. Analogue experiments and numerical simulation have thus become an integral part of the Earth explorer's toolbox to select, formulate, and test hypotheses on the origin and evolution of geological phenomena.
To foster synergy between the rather independently evolving experimentalists and modellers we provide a multi-disciplinary platform to discuss research on tectonics, structural geology, rock mechanics, geodynamics, volcanology, geomorphology, and sedimentology.
We therefore invite contributions demonstrating the state-of-the-art in analogue and numerical / analytical modelling on a variety of spatial and temporal scales, varying from earthquakes, landslides and volcanic eruptions to sedimentary processes, plate tectonics and landscape evolution. We especially welcome those presentations that discuss model strengths and weaknesses, challenge the existing limits, or compare/combine the different modelling techniques to realistically simulate and better understand the Earth's behaviour.
Special issue announcement:
Are you an analogue modeller and working on basin inversion? Please consider submitting your work to the upcoming special issue on analogue modelling of basin inversion in Solid Earth, edited by Frank Zwaan, Michael Rudolf, Riccardo Reitano, Susanne Buiter, Ernst Willingshofer and Guido Schreurs.
The call for submission will open on the 1st of October 2021
More info: https://www.solid-earth.net/articles_and_preprints/scheduled_sis.html
3-D Geological Models as Scientific Tools for Joint Inversion, Uncertainty Quantification, and Machine Learning
Geological models are key to our understanding of the subsurface by providing both visual and quantitative context. But accurately modeling the significant heterogeneities, discontinuities and the uncertainties of geological systems from often sparse data remains challenging. Substantial developments in geomodeling over the past years has helped bridge the gap between input data and resulting geomodel, allowing for the (semi-)automated construction of geomodels, a quicker model validation and rebuilding when new data arrives, as well as an efficient testing of multiple hypotheses. Increasing computing power now also allows for effective stochastic simulation of uncertainties in geomodelling, as well as the integration of probabilistic inference frameworks and geophysical inversions. Machine learning approaches can be used in every step of the geomodeling pipeline to enhance the process: from automated input data extraction and classification to probabilistic model selection.
We seek here contributions from all geoscientists using 3-D geological modelling methods, as well as novel developments to construct these models, to quantify and communicate uncertainties, and to integrate geological modelling into geophysical inversions. Of special interest are also approaches to combine and enhance geomodelling with machine learning methods. Applications can be in any field of solid earth sciences to address scientific questions throughout the lithosphere/anthroposphere.
TS10 – Rates and age determinations of tectonic processes
Isotopic dating of deformation
Rock deformation continuously rearranges the Earth’s shape. It modifies solid, preexisting rock textures, often in a destructive manner. It can manifest itself in a diversity of ways, ranging from homogeneously distributed to relatively localized. Fluid infiltration and mineral reactions usually accompany/trigger deformation. Dating deformation and its duration is a challenging endeavor, which requires geochemical, petrologic, microstructural and structural characterization in addition to mass spectrometric isotope measurements. In this context, division into pre-, syn-, and post-kinematic mineral growth as well as petrochronological classification is required for a reliable age interpretation.
In this session, we warmly welcome studies that characterize deformation in detail from micro- to macroscopic scale prior to isotopic dating. We would like to discuss innovation, suitability and limitation of the applied method particularly dating deformation rather than metamorphism. We are interested in discussing the significance of the analytical vs. systematic errors in the light of technical improvements enabling analyses of tiny (high spatial resolution) but distinctly different (microtexture) targets with high precision geochronology. Dating of unconventional minerals, systematic sampling/dating strategies of deformed and host rocks and additional geochemical analyses are examples of promising approaches to directly date deformation.
TS11 – Deformation unrelated to regional displacements: salt tectonics, impact geology, magma emplacement
Salt and Shale Tectonics : Recent advances and challenges
This session is open to all recent works on salt-related tectonics, in various tectonic settings (extensional, contractional, strike-slip or simply gravitational, i.e. passive margins), areas of study (onshore or offshore), and types of approaches (subsurface or outcrop interpretation, seismic imaging and processing, numerical or analogue modelling, and rock-mechanics analysis). Likewise, we welcome contributions at various scales from the relationships between crustal-scale tectonics, evaporite deposition and salt tectonics within sedimentary basins and mountains, to the interaction between salt bodies and their surrounding sediments, to intra-salt deformation. Contributions on shale tectonics are also welcome.
Solicited presenters: Mark Rowan and Katherine Giles, Different scales of salt-sediment interaction around passive diapirs
The session deals with the documentation and modelling of the tectonic, deformation and geodetic features of any type of volcanic area, on Earth and in the Solar System. The focus is on advancing our understanding on any type of deformation of active and non-active volcanoes, on the associated behaviours, and the implications for hazards. We welcome contributions based on results from fieldwork, remote-sensing studies, geodetic and geophysical measurements, analytical, analogue and numerical simulations, and laboratory studies of volcanic rocks.
Studies may be focused at the regional scale, investigating the tectonic setting responsible for and controlling volcanic activity, both along divergent and convergent plate boundaries, as well in intraplate settings. At a more local scale, all types of surface deformation in volcanic areas are of interest, such as elastic inflation and deflation, or anelastic processes, including caldera and flank collapses. Deeper, sub-volcanic deformation studies, concerning the emplacement of intrusions, as sills, dikes and laccoliths, are most welcome.
We also particularly welcome geophysical data aimed at understanding magmatic processes during volcano unrest. These include geodetic studies obtained mainly through GPS and InSAR, as well as at their modelling to imagine sources.
The session includes, but is not restricted to, the following topics:
• volcanism and regional tectonics;
• formation of magma chambers, laccoliths, and other intrusions;
• dyke and sill propagation, emplacement, and arrest;
• earthquakes and eruptions;
• caldera collapse, resurgence, and unrest;
• flank collapse;
• volcano deformation monitoring;
• volcano deformation and hazard mitigation;
• volcano unrest;
• mechanical properties of rocks in volcanic areas.
Major advances on imaging subsurface structures have been made in recent years thanks to 3D seismic exploration, tomography, numerical and forward modelling techniques. However, significant problems, and ambiguities in geological interpretation of subsurface data still remain. This session seeks contributions directly related to the practice of interpretation of the Earth's subsurface tectonic structure using subsurface imaging techniques but also combining geophysical geological observations with numerical modelling approaches. The session will address problems related to deep tectonic features, fault structure, fluid-rock interactions using time lapse imaging, storage structure and more generally basin and tectonic analysis. Contributions may include submissions that advance geophysical or geological concepts and principles of seismic interpretation; correlation with and calibration by geological and engineering data; case studies; algorithms for interpretation; image processing and forward modelling techniques. Contributions that describe interpretation methods and applications involving an integration of multiple datasets to quantify as well as visualize subsurface structure are strongly encouraged. Presentations that focus on the large scale structure , basin exploration , CO2 sequestration, and extraction of mineral resources, using seismic datasets, and coupled to geological observations with numerical experiments are welcomed.
Geometrical characteristics of geological structures in 2- and 3-dimensions
Geological structures such as faults, fractures, folds, and associated fabrics are complex 3-D geological objects and, therefore, their thorough understanding intrinsically requires a 3-, in addition to 2-D analysis. In this session, we invite contributions that address the geometrical complexities of geological structures by taking into account their inherent 3-D nature, and we aim at promoting discussion on any similarities or disparities between the geometries of different structures, and on the processes that may develop them. As the integration of different data types can provide insights on the characteristics of geological structures at different scales, we invite contributions that build on a broad spectrum of data, such as outcrop, geophysical imaging, earthquake seismicity, and analogue and numerical modelling data. Contributions based on innovative quantitative methods for building high-resolution 3-D geological models such as, for example, micro-computed tomography or photogrammetric techniques, are also welcome. Further, discussions on the predictive nature of geological structures are encouraged for use in a wide range of industries. This can include estimating fluid flow in reservoirs associated with hydrogeology and hydrocarbons to “green” industries such as CO2 storage and the production of geothermal energy, as well as discussing their importance for earthquake hazard assessment or within the geotechnical, mining or civil engineering sectors.
TS13 – Plate Tectonics and the evolution of the Earth
Complex oceans and margins: Oblique rifts, microcontinents, magmatism, transforms, and other inconveniences
It is becoming increasingly apparent that continental rifting, breakup, and ocean spreading contain significant complexities not easily explained by standard models. Recent discoveries of the importance of obliquity during rifting and continental material far offshore, such as beneath Iceland, the Comoros, Kerguelen, Jan Mayen and Mauritius, challenges conventional tectonic models. The coincidence of many regions of anomalous intraplate- or on-ridge volcanism with continental material, often detected geochemically, hints at imminent breakthroughs in our geodynamic understanding of the ocean floor and rifting processes. New models for the complex dynamics of continental breakup, including precursory deformation and magmatism, the role of shearing, structural inheritance, the structure and meaning of magnetic anomalies, the structural variability at passive margins, the development of spreading centres and the difficult birth of new oceans are required. These models must account for the complex features that are observed, including hybrid crust, marginal ridges, rift axis migration, isolated blocks of heavily rotated lithosphere in the ocean, anomalous bathymetry, and the geochemistry of lavas.
In this session, we explore the formation, evolution, structure, composition and underlying mechanisms controlling the formation of complex oceanic regions and continental margins. We seek case histories from around the globe addressing different geoscience disciplines, such as marine geophysics, seismology, ocean drilling, geochemistry, plate kinematics, tectonics, structural geology, numerical and analogue modelling, sedimentology and geochronology. We particularly encourage cross-disciplinary presentations, thought-provoking studies that challenge conventions, and submissions from early career researchers.
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