Orbital forcing of the martian polar layered deposits

• Published in: Nature
• Main Authors: Laskar, Jacques, Levrard, Benjamin, Mustard, John F.
• Other Authors: Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Department of Geological Science, Brown University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2002
• Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; North Pole; Ice cap
• Online Access: https://hal.archives-ouvertes.fr/hal-03785478; https://doi.org/10.1038/nature01066

International audience Since the first images of polar regions on Mars revealed alternating bright and dark layers, there has been speculation that their formation might be tied to the planet's orbital climate forcing. But uncertainties in the deposition timescale exceed two orders of magnitude: estimates based on assumptions of dust deposition, ice formation and sublimation, and their variations with orbital forcing suggest a deposition rate of 10 -3 to 10 -2 cmyr -1 (refs 5, 6), whereas estimates based on cratering rate result in values as high as 0.1 to 0.2cmyr -1 (ref. 7). Here we use a combination of high-resolution images of the polar layered terrains, high-resolution topography and revised calculations of the orbital and rotational parameters of Mars to show that a correlation exists between ice-layer radiance as a function of depth (obtained from photometric data of the images of the layered terrains) and the insolation variations in summer at the martian north pole, similar to what has been shown for palaeoclimate studies of the Earth. For the best fit between the radiance profile and the simulated insolation parameters, we obtain an average deposition rate of 0.05cmyr -1 for the top 250m of deposits on the ice cap of the north pole of Mars.