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Mars’ long-term interior evolution: Combined collision and thermochemical models constrained by InSight results

Applicant Tackley Paul
Number 175630
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.08.2018 - 31.10.2022
Approved amount 468'709.00
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All Disciplines (2)

Discipline
Geophysics
Astronomy, Astrophysics and Space Sciences

Keywords (6)

lithosphere; giant impact; dichotomy; mantle convection; Mars; crust

Lay Summary (German)

Lead
Im Rahmen dieses Projektes werden wir neue Daten der Mars Insight-Mission und numerische Modelle benutzen, um die Entwicklung von Mars über Milliarden von Jahren zu studieren. Durch die Insight-Mission wird zum ersten Mal ein Seismometer auf dem Mars installiert und der Wärmefluss des Planeten mit einer Sonde gemessen. Unsere State of the Art numerischen Modelle sind in der Lage, die Entwicklung von Mars ausgehend von einem frühen energetischen Einschlag, der die Krustendichotomie bildete, bis zum heutigen Tag zu simulieren. Die Ergebnisse einer großen Anzahl solcher Simulationen werden mit neuen Insight-Messungen sowie bestehenden Beobachtungen verglichen.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Ziel dieses Proposals ist es, ein systematisches Verständnis dafür zu erhalten, wie der gegenwärtige Zustand von Mars als Ergebnis von 4,5 Milliarden Jahren Entwicklung entstanden ist. Diese Entwicklung beinhaltete wahrscheinlich einen frühen energetischen Einschlag, der die Krustendichotomie bildete, gefolgt von Milliarden von Jahren kontinuierlicher Entwicklung. Die numerische Modellierung wird eine Verbindung zwischen den Details dieser verschiedenen Phasen und den heutigen Beobachtungen herstellen. Das Berner Team modelliert die Kollisionen und dessen unmittelbare Folgen, das ETHZ-Team die nachfolgende langfristige Entwicklung bis heute. Ein automatisierter Vergleich der Simulationsergebnissen mit Insight und anderen Daten mittels maschinellen Lernens ermöglicht es, eine Datenbank mit möglichen Modellen und Evolutionsszenarien aufzubauen.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Die Mars Insight Mission, bei der die Schweiz beteiligt ist, bietet eine einzigartige Gelegenheit, unser Wissen über das Innere von Mars zu verbessern. In diesem Projekt werden wir von den neuen Daten Gebrauch machen, um unser Verständnis der langfristigen Entwicklung von Mars grundlegend zu erweitern.

Direct link to Lay Summary Last update: 06.06.2018

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
160120 Formation and Evolution of planetary systems 01.04.2015 Project funding

Abstract

The upcoming Mars Insight mission (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport), in which Switzerland is involved, provides a unique opportunity to gain a first-order improvement in our knowledge of Mars’ interior. This spacecraft, due to land on Mars on 26 November 2018, will be the first to deploy a seismometer on Mars, the first to measure heat flux using a probe, and will also gather high-precision geodetic data on the rotation and orientation of Mars. Seismic data has been key to determining the interior structure of the Earth and the Moon; thus the InSight mission is set to provide a fundamental breakthrough in our knowledge of Mars’ interior structure.Here we propose to exploit this fundamental advance in our knowledge of the present-day structure of Mars in order to constrain its long-term thermo-chemical evolution. This recognises that the present state of a planet is the result of billions of years of evolution from an early post-accretion phase. Mars’ old surface and lack of plate tectonics indicates that it still retains a strong memory of early processes; thus, to a much greater extent than for Earth or Venus, observations of its present-day internal structure and surface can constrain very well its evolution from very early times to the present day. The goal of this proposal is to obtain a systematic understanding of how the current state of Mars has arisen as a result of 4.5 billions of years of evolution from an early post-accretion phase. This evolution likely included an early giant impact that formed the crustal dichotomy, followed by billions of years of more gradual evolution. Numerical modelling will provide a quantitative link between the details of these phases and present-day observations. Two distinct Subprojects are required: the first will study the early impact and immediate post-impact phase, and the second will study the subsequent long-term evolution to the present day. The “impact“ Subproject focusses on impact simulations using a smoothed-particle hydrodynamics approach coupled with global models of the immediate post-impact phase, which track in particular the cooling and solidification of the resulting regional magma ocean and the sinking and merging of impactor core with Mars’ core. The “long-term“ Subproject uses the data from the first subproject to study the evolution from the post-impact structure to the present day by running of order 10,000 3-D simulations of Mars’ thermo-chemical evolution, varying the key parameters and initial conditions. This high number of calculations is required to cover a large enough fraction of the multidimensional parameter space. An automated analysis (based on the one developed for the ERC iGeo project (Atkins et al. 2016); see also Baumann & Kaus (2015)) of the simulation outcomes will allow us to build a database of dynamically-possible models and evolution scenarios. Based on the numerical results we will compile a database including results on expected present-day crustal mass, crustal thickness, crustal age, dynamo shut-off time and heat flux. These data will be compared to new InSight observations, as well as as a wide range of existing observations, to constrain the range of evolution scenarios and parameters that are consistent with data.The proposed project strengthens a collaboration between ETH Zurich (D-ERDW; “long-term“ Subproject) and the University of Bern (Physics Institute; “impact“ Subproject), which already have a successful collaboration within the framework of the PlanetS NCCR, as well as a long-term international collaboration with the Bayerisches Geoinstitut, University of Bayreuth in Germany.
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