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Updated: May 25, 2025

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Simulation of the Planetary Interior Differentiation Processes in the Laboratory
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Glacial isostatic adjustment reveals Mars's interior viscosity structure
A Broquet1, A-C Plesa2, V Klemann3
1Institute for Planetary Research, German Aerospace Center, DLR, Berlin, Germany. adrien.broquet@dlr.de.
Nature
|February 26, 2025
Summary
Mars
Area of Science:
- Planetary Science
- Geophysics
- Glaciology
Background:
- Glacial isostatic adjustment (GIA) is key to understanding planetary viscosity.
- GIA studies are rare on other planets due to limited observational data.
- Mars' north polar cap is a unique feature for GIA analysis.
Purpose of the Study:
- Investigate the emplacement of Mars' north polar ice cap.
- Determine Mars' present-day internal viscosity structure.
- Constrain GIA models using new data.
Main Methods:
- Combined thermal evolution models.
- Viscoelastic deformation calculations.
- Analysis of radar observations, gravity field data, and seismic data.
Main Results:
- Ongoing downward motion in Mars' northern regions.
- High viscosity (2-6 × 10^22 Pa·s below 500 km) is required.
- Models consistent with thick crusts (>40 km) and depleted mantle (>90% radiogenic elements).
Conclusions:
- Mars' north polar cap formed 1.7–12.0 Myr ago.
- Lithospheric deformation is <0.13 mm/year.
- Future gravity missions will further constrain Martian GIA.
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