{"id":14801,"date":"2026-07-08T14:44:06","date_gmt":"2026-07-08T12:44:06","guid":{"rendered":"https:\/\/wp.unil.ch\/geoblog\/?p=14801"},"modified":"2026-07-08T14:44:08","modified_gmt":"2026-07-08T12:44:08","slug":"the-thermal-structure-of-the-lower-continental-crust-variability-of-properties-from-two-boreholes-and-their-impact-on-heat-flow-model-uncertainties","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/geoblog\/2026\/07\/the-thermal-structure-of-the-lower-continental-crust-variability-of-properties-from-two-boreholes-and-their-impact-on-heat-flow-model-uncertainties\/","title":{"rendered":"The thermal structure of the lower continental crust: variability of properties from two boreholes and their impact on heat flow model uncertainties"},"content":{"rendered":"<figure class=\"wp-block-post-featured-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"731\" src=\"https:\/\/wp.unil.ch\/geoblog\/files\/2026\/07\/projet-dive.jpg\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"projet dive\" style=\"object-fit:cover;\" srcset=\"https:\/\/wp.unil.ch\/geoblog\/files\/2026\/07\/projet-dive.jpg 1000w, https:\/\/wp.unil.ch\/geoblog\/files\/2026\/07\/projet-dive-300x219.jpg 300w, https:\/\/wp.unil.ch\/geoblog\/files\/2026\/07\/projet-dive-768x561.jpg 768w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/figure>\n\n\n<div class=\"wp-block-group has-accent-5-background-color has-background has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"has-accent-5-background-color has-text-color has-background has-link-color wp-elements-524331acae769366d1df8f97507c3307 wp-block-paragraph\" style=\"color:#212121;font-size:clamp(14px, 0.875rem + ((1vw - 3.2px) * 0.49), 19px);\"><em>Th\u00e8se en sciences de la Terre, soutenue le 18 ao\u00fbt 2026 par Kim Lemke, rattach\u00e9e \u00e0 l&rsquo;Institut des sciences de la Terre (ISTE) de la FGSE.<\/em><\/p>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">La lithosph\u00e8re est la peau de la Terre \u00e0 travers laquelle elle perd sa chaleur interne. Ce processus influence par exemple l\u2019\u00e9volution des volcans, la transformation des roches en profondeur, et le potentiel g\u00e9othermique.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">L\u2019objectif de cette th\u00e8se est une analyse thermique d\u00e9taill\u00e9e de la partie la plus m\u00e9connue de la lithosph\u00e8re&nbsp;: la partie inf\u00e9rieure de la cro\u00fbte continentale. Gr\u00e2ce \u00e0 deux forages scientifiques dans les Alpes, 1500 m\u00e8tres de nouvelles roches venant de ces profondeurs ont fait surface. Leurs analyses en laboratoire, compl\u00e9ment\u00e9es par des mod\u00e9lisations num\u00e9riques, permettent de mieux comprendre les propri\u00e9t\u00e9s thermiques de la cro\u00fbte et ainsi le flux de chaleur \u00e0 travers la lithosph\u00e8re.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Les mesures des propri\u00e9t\u00e9s thermiques r\u00e9v\u00e8lent deux grandes unit\u00e9s avec des caract\u00e9ristiques diff\u00e9rentes. La cro\u00fbte moyenne, compos\u00e9e surtout d\u2019anciens s\u00e9diments enfouis, est thermiquement plus conductrice, et sa production de chaleur par d\u00e9sint\u00e9gration radioactive peut atteindre des niveaux typiques de la cro\u00fbte sup\u00e9rieure. En contraste, la cro\u00fbte inf\u00e9rieure, compos\u00e9e surtout de roches pauvres en silice, est environ 20% moins conductrice et produit jusqu\u2019\u00e0 30 fois moins de chaleur. Une grande variabilit\u00e9 interne caract\u00e9rise les deux unit\u00e9s, et cette variabilit\u00e9 augmente vers de plus grandes \u00e9chelles spatiales. De ce fait, l\u2019\u00e9chantillonnage d\u00e9taill\u00e9 est justifi\u00e9 et recommand\u00e9 pour les futures \u00e9tudes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">En se basant sur les propri\u00e9t\u00e9s thermiques ci-dessus, ainsi que la variation de l\u2019\u00e9paisseur typique des couches observ\u00e9e dans les forages, des incertitudes du champ thermique de la lithosph\u00e8re ont \u00e9t\u00e9 calcul\u00e9es. De nombreux types de mod\u00e8les ont \u00e9t\u00e9 r\u00e9alis\u00e9s et \u00e9valu\u00e9s statistiquement. Il s\u2019av\u00e8re que la variabilit\u00e9 des propri\u00e9t\u00e9s thermiques cause des incertitudes non-n\u00e9gligeables \u00e0 la fois en temp\u00e9rature et en termes de flux de chaleur. De plus, ces incertitudes sont pires dans des mod\u00e8les \u00e0 couches \u00e9paisses, une pratique assez courante mais inexacte.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">En conclusion, les r\u00e9sultats soulignent l&rsquo;importance de bien caract\u00e9riser la variabilit\u00e9 des propri\u00e9t\u00e9s thermiques et de travailler avec des mod\u00e8les \u00e0 haute r\u00e9solution spatiale pour toute application impliquant des processus g\u00e9ologiques d\u00e9pendant de la temp\u00e9rature. Du point de vue de la cro\u00fbte continentale, une structure \u00e0 trois couches&nbsp;: cro\u00fbte sup\u00e9rieure, moyenne et inf\u00e9rieure est justifi\u00e9e dans les futurs mod\u00e8les thermiques et g\u00e9odynamiques.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Th\u00e8se en sciences de la Terre<\/p>\n","protected":false},"author":47,"featured_media":14802,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":"","_links_to":"","_links_to_target":""},"categories":[49465],"tags":[],"class_list":["post-14801","post","type-post","status-publish","format-standard","has-post-thumbnail","category-theses-soutenues"],"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14801","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/users\/47"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/comments?post=14801"}],"version-history":[{"count":1,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14801\/revisions"}],"predecessor-version":[{"id":14804,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14801\/revisions\/14804"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media\/14802"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media?parent=14801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/categories?post=14801"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/tags?post=14801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}