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Delamination dynamics in collisional orogens: 3-D thermomechanical modelling coupled with surface processes

English title Delamination dynamics in collisional orogens: 3-D thermomechanical modelling coupled with surface processes
Applicant Gerya Taras
Number 149252
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.03.2014 - 31.03.2016
Approved amount 226'073.00
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All Disciplines (2)

Discipline
Geophysics
Geology

Keywords (5)

subduction; surface processes; delamination; continental collision; numerical modeling

Lay Summary (German)

Lead
Delamination ist ein Prozess der Entfernung des kontinentalen lithosphärischen Mantels in den Tiefen von Kollisionszonen. Dieser Prozess kann zu bogenartigen Geometrien in den mobilen Gebirgsketten führen, welche über solchen Zonen entstehen. Das bisherige Verständnis des Delaminationsprozesses ist jedoch weiterhin vorläufig. Dies auch, weil Initiation, und Dynamik der Delamination bisher nicht in drei Dimensionen nachvollzogen worden sind, insbesondere unter Anwendung von Computermodellen.
Lay summary

Ziele dieses Forschungsprojektes sind: (1) die dreidimensionale Dynamik der Delamination in Kollisionsorogenen numerisch zu untersuchen, (2) den Einfluss vollständig erfasster dreidimensionaler Geometrien auf die dynamische Entwicklung gebirgsbildender Zonen zu studieren, (3) die Rolle der Wechselwirkung zwischen tektonischen und Oberflächenprozessen zu erforschen, und (4) quantitative Modellvorhersagen abzuleiten, welche mit reellen Daten moderner und alter Delaminationszonen verglichen werden können.

Aus den numerischen Experimenten wird ein Satz multidisziplinärer Vorhersagen zur Verfügung stehen, welcher unser Verständnis des Delaminationsprozesses verbessern und die Interpretation natürlicher Daten delaminierender Gebirge korrigieren helfen wird. Die erwarteten Ergebnisse tragen auch in geeigneter Weise dazu bei, das unzureichend erfasste Wechselspiel zwischen tiefen Krusten- und Mantelprozessen sowie der Entwicklung der Oberflächentopographie in Gebirgskettensystemen besser zu verstehen. Der Vergleich von Modellresultaten mit repräsentativen geologischen Fallbeispielen wird durch die Zusammenarbeit mit Experten in regionalen tektonischen Feldstudien aufgewertet.

Direct link to Lay Summary Last update: 28.09.2013

Lay Summary (English)

Lead
Delamination is a process of removal of the continental lithospheric mantle under collision zones. This process often causes arc-like curvature of resulting migrating mountain chains. Delamination remains largely enigmatic, in particular, because its initiation and dynamics has never been studied in three-dimensions with the use of realistic computer models.
Lay summary

 

The goals of this project are to (1) investigate numerically the three-dimensional dynamics of delamination in collisional orogens, (2) study the effects of 3-D geometry on dynamic development of mountains-building zones, (3) investigate roles of dynamic coupling of geological and surface processes, and (4) derive quantitative predictions that can be compared to natural data for modern and ancient delamination zones.
Numerical experiments conducted within this project will deliver a set of multidisciplinary predictions that will improve our understanding of delamination dynamics and help correct interpretation of natural data available for delaminating orogens. The numerical results will also help to understand enigmatic interplays between deep crustal and mantle processes and surface topography evolution in mountain chain systems. The project will profit from collaboration with experts of field-based regional tectonics for comparison of modeling results with representative natural cases.
Direct link to Lay Summary Last update: 28.09.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Geomorphological–thermo-mechanical modeling: Application to orogenic wedge dynamics
Ueda K. Willett S.D. Gerya T. Ruh J. (2015), Geomorphological–thermo-mechanical modeling: Application to orogenic wedge dynamics, in Tectonophysics, 659, 12-30.
Plate tectonics on the Earth triggered by plume-induced subduction initiation
Gerya T.V. Stern R.J. Baes M. Sobolev S. Whattam S.A. (2015), Plate tectonics on the Earth triggered by plume-induced subduction initiation, in Nature, 527, 221-225.

Collaboration

Group / person Country
Types of collaboration
Prof. L.Jolivet, University of Orleans France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Prof. J.-P.Burg, Geological Institute, ETH-Zurich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Prof. R. Stern, Geosciences Department, University of Texas at Dallas United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Communication with the public

Communication Title Media Place Year
Media relations: print media, online media How Plate Tectonics started on Earth GFZ Potsdam, Media & Communication International 2015
Media relations: print media, online media How the shell of ancient Earth cracked, giving rise to moving continents Science International 2015
Media relations: print media, online media Plate tectonics thanks to plumes? ETH News International 2015

Awards

Title Year
Top 2 among 25 hottest articles in Tectonophysics (July to September 2015) http://top25.sciencedirect.com/subject/earth-and-planetary-sciences/9/journal/tectonophysics/00401951/archive/66 2015

Associated projects

Number Title Start Funding scheme
166063 Mantle control and surface expressions of continental destabilization processes - 3D coupled modelling of plume-lithosphere interaction, break-up, to long-term passive margin evolution 01.04.2016 Project funding

Abstract

Delamination is an important processes in the long-term evolution of continental collision zones. The delamination process is naturally three-dimensional and often causes complex arcuate curvature of resulting orogenic systems with dynamically evolving and migrating topography patterns. Yet, the dynamics of subduction-collision zones and associated topographic evolution has not been modelled in three-dimensions to date. Although delamination has been invoked for several collisional orogens, its identification and fingerprinting either relies on large-scale, subsurface geophysical data, or on the exposure of geological data observed at the present-day surface. Little attention has been paid in large-scale (mantle-depth) geodynamic modelling to accurately reproduce the topography and exposure of geological information shaped by the evolution of the surface, despite the demonstrated dynamic effects of surface processes and their potential to influence exhumation patterns. Recent methodological developments, and findings in 2-D delamination modelling and 3-D modelling of subduction/collision systems, make it now viable to carry out systematic 3-D high-resolution numerical simulations of delaminating subduction-collision zones. In addition, new techniques have been recently proposed to model Earth surface erosion and mass transport efficiently and accurately, permitting coupling to large-scale thermomechanical models.Here, we propose to (1) numerically investigate the three-dimensional dynamics of delamination in collisional orogens, where slab dynamics govern the separation of lithospheric mantle from the lower crust, (2) study the effects of 3-D geometry on dynamic development of subduction-collision zones and their orogens, (3) compare dynamic model evolution with and without self-consistent coupled surface processes, and (4) to derive a set of multidisciplinary predictions for surface and subsurface observables that can be compared to geological examples.The project fills a topical gap in three-dimensional modelling of orogenic and subduction processes using our recent 3-D petrological-thermomechanical numerical geodynamic modelling code. This code is combined with a newly developed surface process model, drawing on ongoing collaborative development. Coupled high-resolution thermomechanical and surface-process modelling at this scale is unprecedented and expected to deliver novel insights into the dynamics of orogeny. Its application to orogenic delamination will exploit the capabilities of the methods and is, in terms of surface observations, of particular interest because of the inherent gradual transition from what has been dubbed “tectonic” to “dynamic” topography. Numerical experiments will deliver a set of multidisciplinary predictions that together with dynamic self-consistency of the numerical model will improve an integrated interpretation of data available for delaminating orogens, with the particular strength that parametric sensitivity studies of dynamic models can be taken to derive a variability assessment of the observations. The study will profit from collaboration with experts of field-based regional tectonics for comparison of modelling results with representative natural cases. The results are also expected to enhance the ability of researchers to assess the sensitivity of large-scale model predictions, used in geological interpretations, to the inclusion of surface processes. The project requires skills on a Post-Doctoral level. We request funds for two years for one Post-Doc and research costs involved with this position.
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