Project

Discipline

mantle plume; surface processes; continental breakup; delamination; numerical modeling

Lead
Das Auseinanderbrechen von Kontinenten führt zu charakteristischer Topographie, Fluss- und Ablagerungsbildern, Bruchmustern, und seismischer Aktivität. Dieser oberste, krustale Ausschnitt des Kontinents ist jedoch klein, und komplexe Tiefenprozesse, bezeugt durch lokale magmatische Aktivität, wirken destabilisierend. Aktuelle Forschungsergebnisse zeigen dass die Interaktion von Platte und Erdmantel über einen längeren Zeitraum eine bedeutende Rolle spielt. Rapides Aufsteigen heissen Mantels (sog. “plumes”) kann besonders zur Destabilisierung führen und das Aufbrechen der Platte oder die Entfernung des lithosphärischen Mantels befördern.
Lay summary
Das Projekt behandelt die grossräumige Extension von Kontinenten  in Interaktion mit dem Mantel, sowie das kleinerräumige oberflächennahe Erscheinungbild, ähnlich wie der Feldforschung zugänglich. Es baut auf einer Verzahnung eines thermomechanischen Modells mit einem Landschaftsentwicklungsmodell auf, um die geodynamische Entwicklung von Platte und Mantel im Grossen und der Krusten- und Oberflächendynamik im Kleinen in sich stimmig innerhalb ein und desselben numerischen Experiments zu untersuchen Ziele sind: 1) das Grundlagenverständnis für Zusammenspiel und  Resonanzmechanismen von Mantel, Lithosphärenplatte, und Oberfläche für generelle Extension zu verbessern; 2) Unterschiede auf verschiedenen Beobachtungebenen im Falle extern angelegter bzw. intern resultierender Extension zu explorieren; 3)  Beiträge von plumes zum Aufbrechen und zum sedimentären, magmatischen, und geomorphologischen Erscheinungsbild zu verstehen; 4) anhand der Langzeitentwicklung im Stadium passiver Kontinentalränder Entwicklung und Migration von langlebigen Steilstufen (rift escarpments) zu untersuchen, sowie mit vereinfachten Oberflächenmodellen zu vergleichen.

Direct link to Lay Summary

Last update: 07.04.2016

Lead
Continental break-up leads to characteristic, evolving patterns in topography, fluvial- and depositional, faulting, and seismicity patterns. Beyond this limited crustal excerpt, deeper processes, as testified by local magmatic activity, play a major role in continental destabilization. Recent results indicate that the long-term mantle-lithosphere interaction, in particular as plumes, bears high potential for destabilization, initiation of rifting, or the removal of mantle lithosphere (delamination).
Lay summary
The project numerically targets large-scale extension and destabilization of continents in interaction with the mantle, and the corresponding local near-surface expressions. It builds on earlier coupling of thermomechanical and landscape evolution models. In this approach, both geodynamic evolution of plate and upper mantle, and crustal and surface dynamics, are modelled self-consistently within one and the same experiment. The objectives are: 1) to advance the understanding for interaction and feedback mechanisms between mantle, lithosphere, and surface, under extension; 2) to explore differences observable at different scales between far-field and internal destabilization and extension scenarios; 3) to track the contributions of mantle plumes to rifting and to magmatic, sedimentary, and geomorphological appearance; 4) on the basis of long-term model evolution, to passive margin stage, to study development and migration of long-lived rift escarpments, and to compare predictions to simpler kinematic landscape evolution models.

Direct link to Lay Summary

Last update: 07.04.2016

Title	Year

Number	Title	Start	Funding scheme

Recent geodynamic studies revealed a critical role of plume-induced processes for initiation of continental rifting and breakup and destabilization of cratonic roots by lithospheric delamination. It has also been demonstrated that plume-lithosphere and generally mantle-lithosphere interactions are intrinsically three-dimensional, strongly evolve with time, and have distinct non-stationary topography expressions. These interactions should also be strongly affected by erosion, sedimentation and plume-induced volcanism and crustal growth, due to intrinsic feedbacks existing between deep lithospheric deformation and crustal and surface evolution. However, so far mantle-lithosphere interactions have never been investigated by means of 3D thermo-mechanical geodynamic modeling coupled to surface process models, which creates an obvious gap both in understanding of these phenomena and relating surface observables to underlaying geodynamic processes. Geological questions pertaining to mantle-lithosphere-surface interactions, such as the origin of long-lived, high-relief escarpments at passive-margins, should be addressed from such an integrated perspective. In our previous SNF-funded project we developed a new high-resolution 4D (space-time) geomorphological-thermo-mechanical numerical modeling tool I3ELVIS-DAC and successfully applied it for a range of geodynamic processes including lithospheric collision and post-collisional delamination processes. With this project we aim to close the gap in our understanding of mantle-lithosphere-surface interactions by applying this new numerical tool for investigating key geodynamic scenarios associated with various types of plume-induced tectono-magmatic processes under conditions of both stressed and stress-free continental lithosphere. We will focus on fingerprinting of deep crustal and lithospheric processes by surface evolution and systematically compare numerical predictions to available natural observations, in particular new quantitative measures of fluvial network disequilibrium, for key continental settings affected by various modes of mantle-lithosphere interaction. The project requires skills on an experienced Post-Doctoral level. We request funds for 2.5 years for one Post-Doc, research costs involved with this position, and resources for the exchange with key scientists in form of a workshop.