Mean age of oceanic lithosphere drives eustatic sea-level change since Pangea breakup

• Published in: Earth and Planetary Science Letters
• Main Authors: Cogné, Jean-Pascal, Humle, Eric, Courtillot, Vincent
• Other Authors: Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique UMR 6112 (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: oceans; sealevel; eustacy; global changes; Pangea breakup; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology; Antarctic; The Antarctic; Indian; Antarc*; Ice cap
• Online Access: https://hal.science/hal-00149123; https://doi.org/10.1016/j.epsl.2006.03.020

International audience The Atlantic and Indian Oceans and the oceanic part of the Antarctic plate have formed at the expense of Panthalassa as a result of Pangea breakup over the last 180 Myr. This major plate reorganization has changed the age vs. surface distribution of oceanic lithosphere and has been a likely driver of sea-level change. Assuming that the age/surface structure of Panthalassa has remained similar to the present-day global distribution from 180 Ma to Present, and using the isochron patterns preserved in the newly formed oceans, we model resulting relative sea-level change. We find a first (slower) phase of sea-level rise (by 90 to 110 m), culminating between 120 and 50 Ma, followed by a (faster) phase of sea-level drop. We show that this result is not strongly sensitive to our hypothesis of constant mean age of Panthalassa, for which much of the information is now erased due to subduction. When the effects of oceanic plateau formation and ice cap development are added, the predicted sea-level curve fits remarkably well the first-order variations of observed sea-level change. We conclude that the changes in mean age of the oceanic lithosphere (varying between 56 and 62 ± 0.2 Myr), which are simply the expression of the Wilson cycle following Pangea breakup, are the main control, accounting for not, vert, similar 70%, of first-order changes in sea-level.