{"id":14565,"date":"2026-06-01T10:11:56","date_gmt":"2026-06-01T08:11:56","guid":{"rendered":"https:\/\/wp.unil.ch\/geoblog\/?p=14565"},"modified":"2026-06-01T10:12:36","modified_gmt":"2026-06-01T08:12:36","slug":"structural-connectivity-functional-connectivity-and-sediment-flux-on-a-deglaciating-alpine-hillslope","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/geoblog\/2026\/06\/structural-connectivity-functional-connectivity-and-sediment-flux-on-a-deglaciating-alpine-hillslope\/","title":{"rendered":"Structural Connectivity, Functional Connectivity and Sediment Flux on a Deglaciating Alpine Hillslope"},"content":{"rendered":"
\"dcim102mediadji<\/figure>\n\n\n
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Th\u00e8se en g\u00e9ographie, soutenue le 26 juin 2026 par Mathilde Bayens, rattach\u00e9e \u00e0 l’Institut des dynamiques de la surface terrestre (IDYST) de la FGSE.<\/em><\/p>\n<\/div>\n\n\n\n

Dans les Alpes, la fonte rapide des glaciers et la d\u00e9gradation du perg\u00e9lisol transforment profond\u00e9ment les paysages de haute montagne. Ces changements mettent \u00e0 nu de grandes quantit\u00e9s de s\u00e9diments et modifient les chemins par lesquels ils descendent vers les vall\u00e9es. Or, ces mouvements de mat\u00e9riaux influencent la stabilit\u00e9 des pentes, la forme des rivi\u00e8res et certains risques naturels. Comprendre comment les s\u00e9diments circulent apr\u00e8s la disparition d\u2019un glacier est donc essentiel.<\/p>\n\n\n\n

Cette th\u00e8se \u00e9tudie ces transformations dans le bassin du Haut Glacier d\u2019Arolla, en Suisse, un site embl\u00e9matique de la d\u00e9glaciation alpine. L\u2019objectif est de comprendre comment les s\u00e9diments passent des versants au fond de vall\u00e9e, et comment cette \u00ab connectivit\u00e9 \u00bb \u00e9volue \u00e0 diff\u00e9rentes \u00e9chelles de temps : sur une saison estivale, sur plusieurs ann\u00e9es et sur plusieurs d\u00e9cennies.<\/p>\n\n\n\n

Pour cela, un versant de deux kilom\u00e8tres a \u00e9t\u00e9 analys\u00e9 gr\u00e2ce \u00e0 trois sources de donn\u00e9es compl\u00e9mentaires. Des relev\u00e9s LiDAR r\u00e9alis\u00e9s par drone permettent d\u2019observer les changements saisonniers avec une grande pr\u00e9cision. Des donn\u00e9es topographiques suisses haute r\u00e9solution renseignent sur les \u00e9volutions pluriannuelles. Enfin, d\u2019anciennes photos a\u00e9riennes, transform\u00e9es en mod\u00e8les 3D, offrent une vision sur plusieurs d\u00e9cennies. Ensemble, ces donn\u00e9es permettent de suivre o\u00f9 la montagne perd du mat\u00e9riel, o\u00f9 elle en accumule, et comment les s\u00e9diments se d\u00e9placent d\u2019un point \u00e0 l\u2019autre.<\/p>\n\n\n\n

Les r\u00e9sultats montrent que la forme du terrain, m\u00eame \u00e0 petite \u00e9chelle, influence fortement la circulation des s\u00e9diments, surtout d\u2019une saison \u00e0 l\u2019autre. Sur le long terme, les mod\u00e8les historiques r\u00e9v\u00e8lent que les chemins permettant aux s\u00e9diments de rejoindre la vall\u00e9e se r\u00e9organisent progressivement apr\u00e8s la fonte du glacier. On observe notamment qu\u2019au fil des d\u00e9cennies, de plus en plus de s\u00e9diments parviennent \u00e0 traverser la moraine situ\u00e9e devant le glacier. Ce ph\u00e9nom\u00e8ne s\u2019explique moins par une augmentation de l\u2019\u00e9rosion que par une \u00e9volution de la connectivit\u00e9 entre les versants et le fond de vall\u00e9e.<\/p>\n\n\n\n

En r\u00e9sum\u00e9, cette th\u00e8se montre que la mani\u00e8re dont les s\u00e9diments circulent apr\u00e8s la d\u00e9glaciation d\u00e9pend autant de la topographie et de l\u2019organisation du paysage que des processus d\u2019\u00e9rosion eux-m\u00eames. Ces r\u00e9sultats am\u00e9liorent notre compr\u00e9hension de l\u2019\u00e9volution des paysages de haute montagne et montrent comment, dans un contexte de r\u00e9chauffement climatique, l\u2019augmentation des apports s\u00e9dimentaires depuis les versants peut en partie compenser la diminution de l\u2019\u00e9rosion glaciaire.<\/p>\n","protected":false},"excerpt":{"rendered":"

Th\u00e8se en g\u00e9ographie<\/p>\n","protected":false},"author":47,"featured_media":14567,"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-14565","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\/14565","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=14565"}],"version-history":[{"count":2,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14565\/revisions"}],"predecessor-version":[{"id":14570,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14565\/revisions\/14570"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media\/14567"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media?parent=14565"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/categories?post=14565"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/tags?post=14565"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}