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Assistant Professor Charles\u2011\u00c9douard Boukar\u00e9<\/a>, Department of Physics and Astronomy, York University<\/a>, led the new study.<\/p>\n Early Earth was a molten world<\/p>\n When the young Earth cooled, it did not freeze evenly like a lake in winter. It simmered from the top down and the bottom up at the same time, leaving pockets of melt trapped deep inside.<\/p>\n Planetary scientists call that global melt a basal magma ocean<\/a>, a deep layer of iron\u2011rich liquid pooling just above the metal core, and its existence explains why the modern core still loses heat so slowly.<\/p>\n Seismic scans of the modern deep mantle reveal sprawling ultralow velocity zones that slow earthquake waves, hinting they contain that same dense, iron\u2011heavy melt and supporting the basal ocean concept.<\/p>\n These reservoirs sit beneath the Pacific and Africa today, covering areas wider than the continental United States, yet they are hard to image because they lie nearly eighteen hundred\u202fmiles down.<\/p>\n Exactly when those structures formed has been uncertain because many earlier simulations<\/a> treated the mantle as a single gooey fluid, erasing the complex dance between liquid and crystal that governs segregation.<\/p>\n Modeling magma to solid rock<\/p>\n The code named Bambari by the researchers divided Earth\u2019s interior into a fine grid and began with a half\u2011melted mantle<\/a>, about fifty\u202fpercent liquid, a state thought to be realistic after the giant impact that created the Moon.<\/p>\n Temperature contrasts made lighter crystal mush rise while heavier, iron\u2011loaded droplets sank, all as heat bled into cold space, and the model resolved motions at scales from global overturns to turbulent eddies only a few miles across.<\/p>\n Within a few thousand simulated years the top hundred\u202fmiles had cooled enough for crystals to lock together, forming down\u2011plunging sheets that ferried a shallow chemical signal into the deep, a result that surprised the research team.<\/p>\n More crystals formed near the surface than near the core, overturning the textbook view that solidification begins at depth, and the outcome hints that early Earth might have sported a short\u2011lived rocky crust that repeatedly sank back into the mantle.<\/p>\n Because the falling crystals reheated and partly melted on the way down, they left behind an iron\u2011rich brew that eventually puddled into an ocean<\/a> of liquid rock roughly three hundred miles thick above the core, one that may have persisted for half a billion years and acted as a blanket trapping core heat.<\/p>\n Surprising chemistry on early Earth<\/p>\n Low\u2011pressure minerals such as olivine<\/a> were expected to dominate only the upper mantle, yet Boukar\u00e9\u2019s run shows their fingerprints nearly twelve\u2011hundred\u202fmiles below.<\/p>\n This finding that forces a rethink of how trace elements were sorted. The reason is mechanical: surface\u2011grown crystals fell like hailstones, skipping equilibrium reactions at depth.<\/p>\n As they sank, mass balance pumped iron\u2011rich melt upward where it chilled, creating downwellings enriched in trace elements such as samarium and neodymium, and the pattern repeated until the mantle became mostly solid.<\/p>\n That process stamped unusual Lu\/Hf and Sm\/Nd ratios<\/a> that still appear in 3.8 billion\u2011year\u2011old rocks from Greenland, offering a rare chemical time capsule of early differentiation.<\/p>\n \u201cThis study is the first to demonstrate that the first\u2011order features of Earth\u2019s lower mantle structure were established four\u202fbillion\u202fyears ago,\u201d said Boukar\u00e9.<\/p>\n Remnants in Earth\u2019s mantle today<\/p>\n The simulation naturally birthed the two giant \u201csuperplumes<\/a>,\u201d formally known as large low shear\u2011velocity provinces or LLSVPs, that sit under the Pacific and Africa and rise more than six\u2011hundred\u202fmiles off the core.<\/p>\n In the model they form as the dregs of the magma ocean, loaded with iron and slightly radioactive elements that keep them hotter than their surroundings, an explanation that unifies decades of seismic<\/a> and geochemical hints.<\/p>\n That extra heat helps feed volcanic hotspots such as Hawaii and Iceland, linking events separated by billions of years through persistent mantle<\/a> circulation.<\/p>\n High\u2011precision noble\u2011gas measurements in ocean\u2011island basalts point to ancient, undegassed mantle domains that match the predicted reservoirs, giving independent support to the model\u2019s deep\u2011time narrative.<\/p>\n Because the model reproduces both seismic and chemical observations, it knits together disciplines that rarely intersect and offers a single story for the planet\u2019s deep past.<\/p>\n What this means for other planets<\/p>\n The equations behind Bambari apply to any rocky world, big or small, making the tool valuable far beyond Earth studies.<\/p>\n For Mars<\/a>, whose lower mass bleeds heat faster, the basal magma ocean would have frozen early, starving the core of insulation and hastening the loss of its magnetic shield within a few hundred million years, a scenario that dovetails with rover data<\/a> showing weak residual magnetism in surface rocks.<\/p>\n For a super\u2011Earth twice our planet\u2019s size, the same physics predicts a magma ocean that could linger a billion\u202fyears, sustaining a long\u2011lived dynamo and perhaps protecting an atmosphere long enough for life to emerge.<\/p>\n \u201cIf we know some kind of starting conditions, and we know the main processes of planetary evolution<\/a>, we can predict how planets will evolve,\u201d Boukar\u00e9 explained. That prospect gives exoplanet hunters a fresh tool for judging habitability without leaving the telescope.<\/p>\n The study is published in Nature<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.\u00a0<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Earth started out as a ball of liquid fire, its newborn surface closer to a lava lamp than…\n","protected":false},"author":2,"featured_media":255824,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3844],"tags":[70,413,16,15],"class_list":{"0":"post-255823","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-uk","11":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/114833900400604076","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/255823","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=255823"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/255823\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/255824"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=255823"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=255823"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=255823"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}