Artists view of Mars interior structure showing a molten layer at the base of the mantle and above the core. The purple line reveals the course followed in Mars by the waves produced by the meteorite effect that happened on September 2021 and diffracted along the CMB.
Recently, a group of researchers included in NASAs InSight objective completed an analysis of seismic data tape-recorded on Mars after a meteorite effect that happened in September 2021. Their findings drastically alter our view of the internal structure and advancement of the Red Planet.
Based upon these results and previous geophysical data, a study published in the journal Nature, in which scientist Attilio Rivoldini from the Royal Observatory of Belgium got involved, proposes a new model for the interior of Mars, with a heterogeneous mantle including a molten silicate layer above the liquid metal core.
Preliminary Findings and Assumptions
The very first outcomes based on data from the InSight objective significantly enhanced our understanding of the interior structure of Mars. Assuming that the mantle is compositionally homogeneous and totally solid, the results revealed that the liquid metal core has a radius of about 1830 ± 40 km and a fairly low density (6-6.2 g/cm3) with a large concentration of light elements. The size of the metal core was determined by the detection of seismic waves reflected at a solid-liquid interface credited be the Core-Mantle Boundary (CMB).
Re-Evaluation After Recent Impact
Considering that then, the analysis of brand-new information generated by a powerful meteorite impact that happened on September 18, 2021, questioned the first estimates of the internal structure of the Red Planet. A global team led by Henri Samuel, CNRS researcher at the Institute of Globe Physics in Paris, and including Attilio Rivoldini from the Royal Observatory of Belgium, studied the proliferation times of these waves and revealed that a molten silicate layer at the base of the Martian mantle and above the metallic core can discuss the new information.
Based on this finding, a new structure model has been deduced and released on October 26 in the journal Nature. That structure model is not just more consistent with all readily available geophysical information, but also explains much better the evolution of Mars because its development.
Seismic Anomalies Explained
A molten layer at the base of the mantle illuminates the unusually slow propagation, hitherto inexplicable, of seismic waves diffracted along the CMB in September 2021. Moreover, for numerous earlier seismic events, the arrival times of seismic waves work with reflections of seismic shear waves at the top of the molten layer (situated numerous 10s of kilometers above the metallic core) and not at the CMB, as previously assumed.
Implications for Core Size and Composition
The presence of this molten layer at the base of the mantle indicates that the metallic core is 150 to 170 km smaller (i.e., a radius of 1650 ± 20 km) than previous estimates.
” This smaller sized core is likewise 5 to 8% denser (i.e. 6.5 g/cm3). The fraction of light aspects in the core is lower than formerly thought and as such is more compatible with cosmochemical information deduced from the analysis of Martian meteorites and high-pressure experiments,” describes Attilio Rivoldini.
Mars Early Evolution
The authors of the research study therefore propose that Mars experienced an early magma ocean stage whose crystallisation produced a stable layer at the base of the mantle, highly enhanced in iron and radioactive elements. The heat launched by radioactive decay generated a basal layer of molten silicates above the core.
For more on this research study:
Referral: “Geophysical evidence for an enriched molten silicate layer above Marss core” by Henri Samuel, Mélanie Drilleau, Attilio Rivoldini, Zongbo Xu, Quancheng Huang, Raphaël F. Garcia, Vedran Lekić, Jessica C. E. Irving, James Badro, Philippe H. Lognonné, James A. D. Connolly, Taichi Kawamura, Tamara Gudkova and William B. Banerdt, 25 October 2023, Nature.DOI: 10.1038/ s41586-023-06601-8.
About InSight and SEIS:.
NASAs InSight objective officially ended in December 2022 after more than 4 years of gathering special science information on Mars.
JPL handled the InSight mission on behalf of NASAs Science Mission Directorate. InSight is part of NASAs Discovery program, handled by the Marshall Space Flight Center (MSFC), NASAs Huntsville, Alabama facility. Lockheed Martin Space in Denver constructed the InSight probe, including its cruise stage and lander, and supported operation of the spacecraft for the mission. CNES was the prime contractor for SEIS and the Paris Institute of Globe Physics (Université Paris Cité/ IPGP/CNRS) assumed clinical responsibility. CNES financial resources the French contributions, coordinates the international consortium (*) and was responsible for the combination, screening and supply of the total instrument to NASA. IPGP designed the VBB (Very Broad Band) sensing units, evaluated them before their shipment to CNES and adds to the operation of VBBs on Mars.
The SEIS and APSS operations were carried out by CNES within FOCSE-SISMOC, with the support of the Centro de Astrobiologia (Spain). SEIS data are formatted and distributed by the Mars SEIS Data Service of IPG Paris, as part of the National Observation Service InSight to which LPG likewise contributes and, for Seismo activities at the School, GéoAzur. Daily recognition of earthquakes was performed by InSights Mars Quake Service, a collaborative operational service led by ETH Zurich to which seismologists from IPG Paris, the University of Bristol (UK) and Imperial College London (UK).
Numerous other CNRS laboratories consisting of LMD (CNRS/ENS Paris/ École polytechnique/Sorbonne University), LPG (CNRS/Nantes University/Le Mans University/University of Angers), IRAP (CNRS/University of Toulouse/CNES ), the LGL-TPE (CNRS/ École Normale Supérieure de Lyon/Claude Bernard University Lyon 1), the IMPMC (Sorbonne University/National Museum of Natural History/CNRS) and LAGRANGE (CNRS/Universit é Côte dAzur/ Observatoire of the Côte dAzur) are getting involved with the IPGP and ISAE-SUPAERO in the analysis of data from the InSight mission. These evaluate are supported by CNES and the National Research Agency as part of the ANR MArs Geophysical InSight (MAGIS) job.
( *) in cooperation with SODERN for the production of the VBB, the JPL, the Swiss Federal Institute of Technology in Zurich (ETH, Zurich Switzerland), the Max Planck Institute for Solar System Research (MPS, Göttingen, Germany), the Imperial College London and the University of Oxford offered the SEIS subsystems and are included in the scientific exploitation of SEIS.
Artists view of Mars interior structure showing a molten layer at the base of the mantle and above the core. The purple line reveals the path followed in Mars by the waves generated by the meteorite effect that occurred on September 2021 and diffracted along the CMB. The first outcomes based on data from the InSight mission substantially improved our understanding of the interior structure of Mars. SEIS data are formatted and dispersed by the Mars SEIS Data Service of IPG Paris, as part of the National Observation Service InSight to which LPG likewise contributes and, for Seismo activities at the School, GéoAzur. Daily identification of earthquakes was carried out by InSights Mars Quake Service, a collective functional service led by ETH Zurich to which seismologists from IPG Paris, the University of Bristol (UK) and Imperial College London (UK).