Long-term Earth-Moon evolution with high-level orbit and ocean tide models

TitleLong-term Earth-Moon evolution with high-level orbit and ocean tide models
Publication TypeJournal Article
Year of Publication2021
AuthorsDaher H, Arbic BK, Williams JG, Ansong JK, Boggs DH, Müller M, Schindelegger M, Austermann J, Cornuelle BD, Crawford EB, Fringer OB, Lau HCP, Lock SJ, Maloof AC, Menemenlis D, Mitrovica JX, Green J.A.Mattias, Huber M
JournalJournal of Geophysical Research: Planets
Paginatione2021JE006875
Date Published2021/09/23
Other Numbers77Maloof
KeywordsEarth rotation, Earth-Moon history, Lunar orbit, Ocean tides, plate tectonics
Abstract

Abstract Tides and Earth-Moon system evolution are coupled over geological time. Tidal energy dissipation on Earth slows Earth's rotation rate, increases obliquity, lunar orbit semi-major axis and eccentricity, and decreases lunar inclination. Tidal and core-mantle boundary dissipation within the Moon decrease inclination, eccentricity and semi-major axis. Here we integrate the Earth-Moon system backwards for 4.5 Ga with orbital dynamics and explicit ocean tide models that are “high-level” (i.e., not idealized). To account for uncertain plate tectonic histories, we employ Monte Carlo simulations, with tidal energy dissipation rates (normalized relative to astronomical forcing parameters) randomly selected from ocean tide simulations with modern ocean basin geometry and with 55, 116, and 252 Ma reconstructed basin paleogeometries. The normalized dissipation rates depend upon basin geometry and Earth’s rotation rate. Faster Earth rotation generally yields lower normalized dissipation rates. The Monte Carlo results provide a spread of possible early values for the Earth-Moon system parameters. Of consequence for ocean circulation and climate, absolute (un-normalized) ocean tidal energy dissipation rates on the early Earth may have exceeded today’s rate due to a closer Moon. Prior to 3 Ga, evolution of inclination and eccentricity is dominated by tidal and core-mantle boundary dissipation within the Moon, which yield high lunar orbit inclinations in the early Earth-Moon system. A drawback for our results is that the semi-major axis does not collapse to near-zero values at 4.5 Ga, as indicated by most lunar formation models. Additional processes, missing from our current efforts, are discussed as topics for future investigation.

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URLhttps://doi.org/10.1029/2021JE006875
DOI10.1029/2021JE006875