The Cenozoic Evolution of Earth’s Strongest Geoid Low: Insights into Mantle Dynamics below Antarctica

The Cenozoic Evolution of Earth’s Strongest Geoid Low: Insights into Mantle Dynamics below Antarctica | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article The Cenozoic Evolution of Earth’s Strongest Geoid Low: Insights into Mantle Dynamics below Antarctica Petar Glišović, Alessandro Forte This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5662939/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Constraining the long-term evolution of geoid anomalies is essential for unraveling Earth's internal dynamics. While most studies focus on present-day geoid snapshots, we reconstruct the time-dependent evolution of Earth’s strongest geoid depression, the Antarctic Geoid Low (AGL), over the Cenozoic. Unlike geodetic reference frames that place the deepest geoid low in the Indian Ocean, a geodynamic perspective (relative to a hydrostatic ellipsoid) reveals the strongest nonhydrostatic geoid depression actually resides over Antarctica. Using a back-and-forth nudging technique for time-reversed mantle convection modeling, we leverage 3-D mantle density structures derived from seismic tomography and geodynamic constraints. Our results show that the AGL has persisted for at least ~70 Myr, undergoing a major transition in amplitude and position between 50 and 30 Ma. This coincides with abrupt lateral shifts in Earth’s rotation axis at ~50 Ma, validated through paleomagnetic constraints on True Polar Wander. Initially, stable lower mantle contributions dominated the AGL, but over the past ~40 Myr, increasing upper-mantle buoyancy, particularly above ~1300 km depth, amplified the AGL magnitude. This shift stems from the interplay between long-term deep subduction beneath the Antarctic Peninsula and a buoyant, thermally driven upwelling of hot, low-density material from the lowermost mantle. These new results contrast with earlier interpretations, clarifying the crucial role of evolving mantle buoyancy in shaping global geoid anomalies. By incorporating seismic, geodynamic, and mineral-physics data, our reconstructions provide a more comprehensive understanding of mantle flow beneath Antarctica and offer new insights into the dynamic coupling between lower and upper mantle processes that govern Earth’s long-wavelength geoid evolution. Earth and environmental sciences/Solid Earth sciences/Geodynamics Earth and environmental sciences/Solid Earth sciences/Geology Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5662939","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":408309680,"identity":"360d26a7-8d4d-4bd0-974b-fc3eac3cd29e","order_by":0,"name":"Petar Glišović","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYFAC5oYDQJKHgb0BSBlYEKOFEaqFB0QZSBCnBUJLJIBJwhrM+Rc2HvxRcViGf+bzqxt+FEgw8Ld3J+DVYjnjYcNhnjOHeSRu55Td7AE6TOLM2Q14tRjcONhwmLEtjcdAOiftBg9Qi4FELmEtB3+CtEieSbv5hygt5xsbDvC22QDNZz92myhbLGcwgvxiwyNxJofttoyBBA9Bv5jzHz788UeFhD1/+/FnN9/8sZHjb+8l4DBIdIAAjwGYxKscrIX/AIzJ/oCg6lEwCkbBKBiZAAD2TEpu/1M/sQAAAABJRU5ErkJggg==","orcid":"","institution":"Institut de Physique du Globe de Paris","correspondingAuthor":true,"prefix":"","firstName":"Petar","middleName":"","lastName":"Glišović","suffix":""},{"id":408309681,"identity":"ec2d2e3e-fed3-4940-9613-12975119d3b4","order_by":1,"name":"Alessandro Forte","email":"","orcid":"https://orcid.org/0000-0002-3530-0455","institution":"University of Florida","correspondingAuthor":false,"prefix":"","firstName":"Alessandro","middleName":"","lastName":"Forte","suffix":""}],"badges":[],"createdAt":"2024-12-17 15:05:41","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5662939/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5662939/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83682252,"identity":"fe0fedca-bd4f-4a8a-b087-acecec31d246","added_by":"auto","created_at":"2025-05-30 16:23:44","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3387500,"visible":true,"origin":"","legend":"Article File","description":"","filename":"manuscriptantarcticageoidlowallchangespgAFrev4pgnew.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5662939/v1_covered_245841e5-190a-4d63-9fc4-171588d0a47a.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"The Cenozoic Evolution of Earth’s Strongest Geoid Low: Insights into Mantle Dynamics below Antarctica","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5662939/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5662939/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Constraining the long-term evolution of geoid anomalies is essential for unraveling Earth's internal dynamics. 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Initially, stable lower mantle contributions dominated the AGL, but over the past ~40 Myr, increasing upper-mantle buoyancy, particularly above ~1300 km depth, amplified the AGL magnitude. This shift stems from the interplay between long-term deep subduction beneath the Antarctic Peninsula and a buoyant, thermally driven upwelling of hot, low-density material from the lowermost mantle. These new results contrast with earlier interpretations, clarifying the crucial role of evolving mantle buoyancy in shaping global geoid anomalies. 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