{"id":2778,"date":"2005-04-15T19:50:34","date_gmt":"2005-04-15T17:50:34","guid":{"rendered":"http:\/\/www.laterredufutur.com\/wordpress\/?p=2778"},"modified":"2015-04-03T19:52:40","modified_gmt":"2015-04-03T17:52:40","slug":"glaciation-de-lantarctique-une-origine-atmospherique","status":"publish","type":"post","link":"https:\/\/www.laterredufutur.com\/accueil\/glaciation-de-lantarctique-une-origine-atmospherique\/","title":{"rendered":"Glaciation de l&rsquo;Antarctique : une origine atmosph\u00e9rique"},"content":{"rendered":"<div class=\"1665f18d14f35dd9e7566e1a8ac9a3e9\" data-index=\"1\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block; text-align:center;\"\r\n     data-ad-layout=\"in-article\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-client=\"ca-pub-2860849627502538\"\r\n     data-ad-slot=\"3019501113\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n<p>Voil\u00e0 une d\u00e9couverte qui prouve qu&rsquo;un changement climatique peut \u00eatre radicalement brutal. Deux articles de la revue Paleoceanography, suite \u00e0 une autre publication d\u00e9but 2003 dans Nature, battent en br\u00e8che la th\u00e9orie la plus g\u00e9n\u00e9ralement avanc\u00e9e pour expliquer la formation de la calotte glaciaire de l&rsquo;Antarctique il y a 32 millions d&rsquo;ann\u00e9es. <\/p>\n<p>Durant des d\u00e9cennies, les climatologues ont pens\u00e9 que la s\u00e9paration des terres antarctique et australienne il y a 35 millions d&rsquo;ann\u00e9es avait supprim\u00e9 les courants marins chauds en place, provoquant un refroidissement \u00e0 l&rsquo;origine de la couche de glace de plusieurs kilom\u00e8tres qui recouvrent aujourd&rsquo;hui le p\u00f4le Sud. Mais l&rsquo;analyse de pr\u00e9l\u00e8vements effectu\u00e9s en l&rsquo;an 2000 sur les c\u00f4tes de l&rsquo;\u00eele de Tasmanie (qui fut par le pass\u00e9 un pont reliant les deux continents) sugg\u00e8re un autre sc\u00e9nario.<\/p>\n<p>En effet, les chercheurs de l&rsquo;Universit\u00e9 Purdue (Indiana) et de diff\u00e9rents instituts am\u00e9ricains et internationaux (Su\u00e8de, Canada, Pays-Bas et Royaume Uni) ont retrouv\u00e9 la trace, dans des s\u00e9diments datant de l&rsquo;Eoc\u00e8ne (entre -54 et -35 millions d&rsquo;ann\u00e9es environ), de fossiles de microorganismes associ\u00e9s aux eaux froides. <\/p><div class=\"1665f18d14f35dd9e7566e1a8ac9a3e9\" data-index=\"2\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block; text-align:center;\"\r\n     data-ad-layout=\"in-article\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-client=\"ca-pub-2860849627502538\"\r\n     data-ad-slot=\"3019501113\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n\n<p>Une d\u00e9couverte incompatible avec l&rsquo;hypoth\u00e8se d&rsquo;un courant chaud emp\u00eachant la glaciation jusqu&rsquo;\u00e0 la rupture des continents. L&rsquo;\u00e9quipe note par ailleurs qu&rsquo;il s&rsquo;est \u00e9coul\u00e9 deux millions d&rsquo;ann\u00e9es entre l&rsquo;ouverture des eaux entre la Tasmanie et l&rsquo;Antarctique et le rapide ph\u00e9nom\u00e8ne de glaciation (en quelques milliers d&rsquo;ann\u00e9es). <\/p>\n<p>Pour les scientifiques, l&rsquo;explication la plus plausible \u00e0 l&rsquo;\u00e9nigmatique ti\u00e9deur de cette r\u00e9gion au cours de l&rsquo;Eoc\u00e8ne et son refroidissement ult\u00e9rieur serait une baisse massive et assez subite des niveaux de dioxyde de carbone dans l&rsquo;air. Les m\u00eames avaient d\u00e9j\u00e0 mis en avant cette th\u00e9orie \u00e0 la suite de l&rsquo;analyse de fossiles trouv\u00e9s \u00e0 El Kef en Tunisie (travaux publi\u00e9s au printemps 2004). <\/p>\n<p>Cette th\u00e9orie, qui reste \u00e0 confirmer, renforce les craintes li\u00e9es au r\u00e9chauffement climatique actuel ; elle implique en effet que des changements dans l&rsquo;atmosph\u00e8re peuvent avoir un impact important en une relative br\u00e8ve p\u00e9riode g\u00e9ologique.<\/p>\n<p>source : http:\/\/www.futura-sciences.com\/sinformer\/n\/news5233.php?cx=1<\/p>\n<p class=\"bawpvc-ajax-counter\" data-id=\"2778\">(507)<\/p>\n<!--CusAds0-->\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>Voil\u00e0 une d\u00e9couverte qui prouve qu&rsquo;un changement climatique peut \u00eatre radicalement brutal. Deux articles de la revue Paleoceanography, suite \u00e0&#8230;<\/p>\n","protected":false},"author":1,"featured_media":2685,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"ngg_post_thumbnail":0,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[33,20],"tags":[1252,252,41,1333,233,251,1330],"class_list":["post-2778","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-archeologie","category-climat","tag-antarctique","tag-atmosphere","tag-climat","tag-glaciation","tag-histoire","tag-origine","tag-source","wpcat-33-id","wpcat-20-id"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/04\/Banquise.jpeg?fit=356%2C278&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p631RN-IO","jetpack-related-posts":[{"id":21823,"url":"https:\/\/www.laterredufutur.com\/accueil\/nouvel-indice-qui-expliquerait-les-glaciations-depuis-2-6-millions-dannees\/","url_meta":{"origin":2778,"position":0},"title":"Nouvel indice qui expliquerait les glaciations depuis 2.6 millions d&rsquo;ann\u00e9es","author":"Admin","date":"15 janvier 2021","format":false,"excerpt":"La Terre est marqu\u00e9e par des cycles de glaciation. Chaque \u00e8re glaciaire \u00e9tant suivie d'une p\u00e9riode interglaciaire. Depuis quelque 2,6 millions d'ann\u00e9es, la Terre conna\u00eet des cycles de glaciation. Elle alterne entre des chutes drastiques de temp\u00e9rature, o\u00f9 une grande partie des continents s'englacent, et r\u00e9chauffement. Sans que les scientifiques\u2026","rel":"","context":"Dans &quot;Climat&quot;","block_context":{"text":"Climat","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/climat\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctique.jpg?fit=1024%2C768&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctique.jpg?fit=1024%2C768&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctique.jpg?fit=1024%2C768&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctique.jpg?fit=1024%2C768&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":24355,"url":"https:\/\/www.laterredufutur.com\/accueil\/une-carotte-de-glace-capsule-temporelle-de-5-millions-dannees-extraite-en-antarctique\/","url_meta":{"origin":2778,"position":1},"title":"Une carotte de glace capsule temporelle de 5 millions d&rsquo;ann\u00e9es extraite en Antarctique","author":"Admin","date":"3 septembre 2022","format":false,"excerpt":"Une \u00e9quipe de scientifiques am\u00e9ricains a r\u00e9cemment dat\u00e9 ce qui pourrait \u00eatre la plus ancienne carotte de glace au monde, offrant un aper\u00e7u pr\u00e9cieux du climat terrestre il y a plusieurs millions d\u2019ann\u00e9es. UNE CAROTTE DE GLACE RECORD La capacit\u00e9 de conservation naturelle exceptionnelle de la glace dans des endroits\u2026","rel":"","context":"Dans &quot;Arch\u00e9ologie&quot;","block_context":{"text":"Arch\u00e9ologie","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/archeologie\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2022\/09\/carotte-glace-antarctique.jpg?fit=1024%2C682&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2022\/09\/carotte-glace-antarctique.jpg?fit=1024%2C682&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2022\/09\/carotte-glace-antarctique.jpg?fit=1024%2C682&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2022\/09\/carotte-glace-antarctique.jpg?fit=1024%2C682&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":24767,"url":"https:\/\/www.laterredufutur.com\/accueil\/des-chercheurs-ont-decouvert-plusieurs-effondrements-de-la-circulation-du-fond-oceanique-depuis-47-millions-dannees\/","url_meta":{"origin":2778,"position":2},"title":"Des chercheurs ont d\u00e9couvert plusieurs effondrements de la circulation du fond oc\u00e9anique depuis 4,7 millions d&rsquo;ann\u00e9es","author":"Admin","date":"25 f\u00e9vrier 2023","format":false,"excerpt":"L'eau profonde de l'Antarctique (AABW) couvre plus des deux tiers du fond de l'oc\u00e9an mondial, et sa formation a r\u00e9cemment diminu\u00e9. Cependant, sa variabilit\u00e9 \u00e0 long terme n'a pas \u00e9t\u00e9 bien comprise. Les chercheurs dirig\u00e9s par le professeur Deng Chenglong de l'Institut de g\u00e9ologie et de g\u00e9ophysique (IGG) de l'Acad\u00e9mie\u2026","rel":"","context":"Dans &quot;Arch\u00e9ologie&quot;","block_context":{"text":"Arch\u00e9ologie","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/archeologie\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/07\/antarctique.jpg?fit=1020%2C573&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/07\/antarctique.jpg?fit=1020%2C573&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/07\/antarctique.jpg?fit=1020%2C573&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/07\/antarctique.jpg?fit=1020%2C573&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":27755,"url":"https:\/\/www.laterredufutur.com\/accueil\/a-quand-remonte-la-derniere-fois-que-lantarctique-etait-libre-de-glace\/","url_meta":{"origin":2778,"position":3},"title":"\u00c0 quand remonte la derni\u00e8re fois que l&rsquo;Antarctique \u00e9tait libre de glace ?","author":"Admin","date":"9 mars 2026","format":false,"excerpt":"L'Antarctique est recouvert d'une calotte glaciaire de plusieurs kilom\u00e8tres d'\u00e9paisseur, mais en a-t-il toujours \u00e9t\u00e9 ainsi ? Et \u00e0 quelle \u00e9poque le continent le plus froid a-t-il \u00e9t\u00e9 libre de glace ? L\u2019Antarctique, qui est pr\u00e8s de quatre fois plus grande que les \u00c9tats-Unis, est presque enti\u00e8rement recouverte d\u2019une couche\u2026","rel":"","context":"Dans &quot;Climat&quot;","block_context":{"text":"Climat","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/climat\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2024\/08\/canyons-antarctique-1.jpg?fit=1200%2C847&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2024\/08\/canyons-antarctique-1.jpg?fit=1200%2C847&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2024\/08\/canyons-antarctique-1.jpg?fit=1200%2C847&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2024\/08\/canyons-antarctique-1.jpg?fit=1200%2C847&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2024\/08\/canyons-antarctique-1.jpg?fit=1200%2C847&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":26537,"url":"https:\/\/www.laterredufutur.com\/accueil\/de-la-glace-vieille-de-plus-dun-million-dannees-extraite-en-antarctique\/","url_meta":{"origin":2778,"position":4},"title":"De la glace vieille de plus d&rsquo;un million d&rsquo;ann\u00e9es extraite en Antarctique","author":"Admin","date":"14 janvier 2025","format":false,"excerpt":"Des scientifiques, parmi lesquels des Fran\u00e7ais, ont for\u00e9 dans les profondeurs de la calotte glaciaire pour retrouver cette glace contenant des informations cruciales pour conna\u00eetre l'histoire climatique de notre plan\u00e8te. Ils ont ainsi repouss\u00e9 le pr\u00e9c\u00e9dent record de 400 000 ans. Plus on fore profond, plus on remonte dans le\u2026","rel":"","context":"Dans &quot;Climat&quot;","block_context":{"text":"Climat","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/climat\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctic.png?fit=551%2C553&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctic.png?fit=551%2C553&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/02\/antarctic.png?fit=551%2C553&ssl=1&resize=525%2C300 1.5x"},"classes":[]},{"id":20736,"url":"https:\/\/www.laterredufutur.com\/accueil\/decouverte-de-vestiges-dune-foret-tropicale-vieille-de-90-millions-dannees-sous-la-glace-antarctique\/","url_meta":{"origin":2778,"position":5},"title":"D\u00e9couverte de vestiges d&rsquo;une for\u00eat tropicale vieille de 90 millions d&rsquo;ann\u00e9es sous la glace antarctique","author":"Admin","date":"1 mai 2020","format":false,"excerpt":"Des traces fossiles d'une ancienne for\u00eat tropicale ont \u00e9t\u00e9 d\u00e9couvertes en Antarctique occidental. Il y a environ 90 millions d'ann\u00e9es, l'Antarctique occidental abritait une for\u00eat pluviale temp\u00e9r\u00e9e florissante, selon les racines fossiles, le pollen et les spores r\u00e9cemment d\u00e9couverts l\u00e0-bas, selon une nouvelle \u00e9tude. Le monde \u00e9tait un endroit diff\u00e9rent\u2026","rel":"","context":"Dans &quot;Arch\u00e9ologie&quot;","block_context":{"text":"Arch\u00e9ologie","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/archeologie\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/04\/foret-tropicale-antarctique.jpg?fit=1024%2C506&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/04\/foret-tropicale-antarctique.jpg?fit=1024%2C506&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/04\/foret-tropicale-antarctique.jpg?fit=1024%2C506&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2020\/04\/foret-tropicale-antarctique.jpg?fit=1024%2C506&ssl=1&resize=700%2C400 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/2778","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/comments?post=2778"}],"version-history":[{"count":1,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/2778\/revisions"}],"predecessor-version":[{"id":2779,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/2778\/revisions\/2779"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/media\/2685"}],"wp:attachment":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/media?parent=2778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/categories?post=2778"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/tags?post=2778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}