A Positive Feedback Between Crustal Thickness and Melt Extraction for the Origin of the Martian Dichotomy - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research. Planets Année : 2022

A Positive Feedback Between Crustal Thickness and Melt Extraction for the Origin of the Martian Dichotomy

Résumé

A North/South difference in crustal thickness is likely at the origin of the Martian dichotomy in topography. Recent crustal thickness maps were obtained by inversion of topography and gravity data seismically anchored at the InSight station. On average, the Martian crust is 51–71 km thick with a southern crust thicker by 18–28 km than the northern one. The origin of this crustal dichotomy is still debated although the hypothesis of a large impact is at present very popular. Here, we propose a new mechanism for the formation of this dichotomy that involves a positive feedback between crustal growth and mantle melting. As the crust is enriched in heat-producing elements, the lid of a one-plate planet is hotter and thinner where the crust is thicker, inducing a larger amount of partial melt below the lid and hence a larger rate of melt extraction and crustal growth. We first demonstrate analytically that larger wavelength perturbations, that is, hemispherical perturbations, grow faster because smaller wavelengths are more attenuated by thermal diffusion. We then use a parameterized thermal evolution model with a well-mixed mantle topped by two different lids characterized by their thermal structures and thicknesses to study the growth of the crust in the two hemispheres. Our results demonstrate that this positive feedback can generate a significant crustal dichotomy
Fichier principal
Vignette du fichier
JGR Planets - 2022 - Bonnet Gibet - A Positive Feedback Between Crustal Thickness and Melt Extraction for the Origin of the.pdf (2.01 Mo) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03936013 , version 1 (12-01-2023)

Licence

Paternité - Pas d'utilisation commerciale

Identifiants

Citer

Valentin Bonnet Gibet, Chloé Michaut, Mark Wieczorek, Philippe Lognonné. A Positive Feedback Between Crustal Thickness and Melt Extraction for the Origin of the Martian Dichotomy. Journal of Geophysical Research. Planets, 2022, 127 (12), pp.e2022JE007472. ⟨10.1029/2022JE007472⟩. ⟨hal-03936013⟩
20 Consultations
20 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More