{"id":30101,"date":"2026-11-06T10:17:08","date_gmt":"2026-11-06T09:17:08","guid":{"rendered":"https:\/\/lpg-umr6112.fr\/?post_type=tribe_events&p=30101"},"modified":"2026-11-06T10:22:09","modified_gmt":"2026-11-06T09:22:09","slug":"seminar-of-jassin-petersen-department-of-earth-sciences-nawi-graz-geocenter-university-of-graz","status":"publish","type":"tribe_events","link":"https:\/\/lpg-umr6112.fr\/en\/event\/seminar-of-jassin-petersen-department-of-earth-sciences-nawi-graz-geocenter-university-of-graz\/","title":{"rendered":"Seminar by Jassin Petersen (University of Graz) “Reconstructions of monsoonal activity in a deglacial context”"},"content":{"rendered":"

Reconstructions of monsoonal activity in a deglacial context<\/strong><\/p>\n

 <\/p>\n

Monsoonal activity and precipitation patterns in southeast Asia and northwestern Australia are driven largely by thermal gradients between the ocean and the continents, and the position of the Intertropical Convergence Zone (ITCZ). A geochemical assessment of sea surface temperature (SST), upwelling, (export) productivity and bottom water oxygenation (BWO)\/ temperature (BWT) allows the inter-hemispheric reconstruction of monsoonal activity. During the most recent deglaciation from the last glacial maximum to the Holocene (Termination 1), and specifically the Younger Dryas (YD; 13-11.7 ka PB) as well as Heinrich Stadial 1 (HS1; ~19-15 ka BP), important global changes, and inter-hemispheric see-saws in paleo-temperatures have been postulated from a multitude of Quaternary proxy-records.<\/p>\n

For this proposed project we intend to sample species of benthic and planktonic foraminifera from surface sediments and sediment cores for geochemical proxy calibration and inter-hemispheric reconstructions for YD and HS1. Two study areas are suited for this purpose: 1) In the northern South China Sea (SCS) upwelling related to the southeast Asian summer monsoon (ASM) is recorded, and 2) on the northwestern continental shelf of Australia (NWA), including the Timor Sea (TS), changes of SST and productivity related to the Australian monsoon (AM) are reconstructed. Both, ASM and AM are modulated by the position of the ITCZ, and NWA\/ TS and the SCS have the relative proximity to the Indonesian Throughflow (ITF) with warm surface waters in common. We attempt to reconstruct the inter-hemispheric see-saws in ITF proximity with a combined approach using elemental ratios as well as stable isotopes. Elemental ratios such as Mg\/Ca from the foraminiferal tests inform us about changes in SST, BWT, (export) productivity, BWO. Laser Ablation ICP-MS (LA-ICP-MS) and electron probe micro-analysis (EPMA) allow us to refine and validate calibration approaches for the targeted elemental ratios. The oxygen and carbon stable isotope data of selected planktonic and benthic foraminifera can reveal information about changes in water column stratification, changes in productivity, and\/or ventilation. Linking productivity and monsoonal activity, we will provide a comparative, high resolution, multi-proxy dataset that will ascertain the cross hemispheric interlinkage of monsoonal activity.<\/p>\n

 <\/p>\n

 <\/p>\n

Reconstitutions de l\u2019activit\u00e9 de la mousson dans un contexte de d\u00e9glaciation<\/strong><\/p>\n

 <\/p>\n

L\u2019activit\u00e9 de la mousson et les r\u00e9gimes de pr\u00e9cipitations en Asie du Sud-Est et dans le nord-ouest de l\u2019Australie sont principalement d\u00e9termin\u00e9s par les gradients thermiques entre l\u2019oc\u00e9an et les continents, ainsi que par la position de la Zone de Convergence Intertropicale (ZCIT). L\u2019\u00e9valuation g\u00e9ochimique de la temp\u00e9rature de surface de la mer (SST), des remont\u00e9es d\u2019eaux profondes, de la productivit\u00e9 (d\u2019export) et de l\u2019oxyg\u00e9nation (BWO) et de la temp\u00e9rature (BWT) des eaux de fond permet de reconstituer l\u2019activit\u00e9 de la mousson entre les deux h\u00e9misph\u00e8res. Au cours de la derni\u00e8re d\u00e9glaciation, depuis le dernier maximum glaciaire jusqu\u2019\u00e0 l\u2019Holoc\u00e8ne (Termination 1), et plus particuli\u00e8rement pendant le Dryas r\u00e9cent (YD ; 13\u201311,7 ka BP) et le stade Heinrich 1 (HS1 ; environ 19\u201315 ka BP), de nombreux enregistrements indirects du Quaternaire ont mis en \u00e9vidence d\u2019importants changements \u00e0 l\u2019\u00e9chelle mondiale, ainsi que des effets de balan\u00e7oire \u00e0 bascule entre les h\u00e9misph\u00e8res dans les temp\u00e9ratures pass\u00e9es.<\/p>\n

Dans le cadre de ce projet, nous souhaitons pr\u00e9lever des esp\u00e8ces de foraminif\u00e8res benthiques et planctoniques dans des s\u00e9diments de surface et des carottes s\u00e9dimentaires, afin d\u2019\u00e9talonner les indicateurs g\u00e9ochimiques et de reconstituer l\u2019activit\u00e9 de la mousson entre les deux h\u00e9misph\u00e8res pendant le YD et le HS1. Deux zones d\u2019\u00e9tude se pr\u00eatent \u00e0 cet objectif : 1) dans la partie nord de la mer de Chine m\u00e9ridionale (SCS), les remont\u00e9es d\u2019eaux profondes li\u00e9es \u00e0 la mousson d\u2019\u00e9t\u00e9 d\u2019Asie du Sud-Est (ASM) sont enregistr\u00e9es ; 2) sur la marge continentale du nord-ouest de l\u2019Australie (NWA), y compris dans la mer de Timor (TS), sont reconstitu\u00e9es les variations de la SST et de la productivit\u00e9 li\u00e9es \u00e0 la mousson australienne (AM). L\u2019ASM et l\u2019AM sont toutes deux modul\u00e9es par la position de la ZCIT. Par ailleurs, le NWA\/TS et la SCS ont en commun leur proximit\u00e9 relative avec le courant maritime indon\u00e9sien (ITF), qui transporte des eaux de surface chaudes. Nous chercherons \u00e0 reconstituer les effets de balan\u00e7oire \u00e0 bascule entre les h\u00e9misph\u00e8res \u00e0 proximit\u00e9 de l\u2019ITF, en combinant les rapports \u00e9l\u00e9mentaires et les isotopes stables. Les rapports \u00e9l\u00e9mentaires, tels que Mg\/Ca dans les tests des foraminif\u00e8res, renseignent sur les variations de la SST, de la BWT, de la productivit\u00e9 (d\u2019export) et de la BWO. La spectrom\u00e9trie de masse par plasma \u00e0 couplage inductif couple \u00e0 l\u2019ablation laser (LA-ICP-MS) et la microanalyse par sonde \u00e9lectronique (EPMA) nous permettront d\u2019affiner et de valider les approches de calibration des rapports \u00e9l\u00e9mentaires cibl\u00e9s. Les donn\u00e9es sur les isotopes stables de l\u2019oxyg\u00e8ne et du carbone mesur\u00e9es chez certaines esp\u00e8ces de foraminif\u00e8res planctoniques et benthiques pourront r\u00e9v\u00e9ler des variations de la stratification de la colonne d\u2019eau, de la productivit\u00e9 et\/ou de la ventilation. En reliant la productivit\u00e9 \u00e0 l\u2019activit\u00e9 de la mousson, nous produirons un jeu de donn\u00e9es comparatif, multi-proxy et \u00e0 haute r\u00e9solution, qui permettra de d\u00e9terminer les liens entre l\u2019activit\u00e9 de la mousson dans les deux h\u00e9misph\u00e8res.<\/p>\n","protected":false},"excerpt":{"rendered":"

Reconstructions of monsoonal activity in a deglacial context   Monsoonal activity and precipitation patterns in southeast Asia and northwestern Australia are driven largely by thermal gradients between the ocean and […]<\/p>\n","protected":false},"author":174,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_price":"","_stock":"","_tribe_ticket_header":"","_tribe_default_ticket_provider":"","_tribe_ticket_capacity":"0","_ticket_start_date":"","_ticket_end_date":"","_tribe_ticket_show_description":"","_tribe_ticket_show_not_going":false,"_tribe_ticket_use_global_stock":"","_tribe_ticket_global_stock_level":"","_global_stock_mode":"","_global_stock_cap":"","_tribe_rsvp_for_event":"","_tribe_ticket_going_count":"","_tribe_ticket_not_going_count":"","_tribe_tickets_list":"[]","_tribe_ticket_has_attendee_info_fields":false,"_tribe_events_status":"","_tribe_events_status_reason":"","_tribe_events_is_hybrid":"","_tribe_events_is_virtual":"","_tribe_events_virtual_video_source":"","_tribe_events_virtual_embed_video":"","_tribe_events_virtual_linked_button_text":"","_tribe_events_virtual_linked_button":"","_tribe_events_virtual_show_embed_at":"","_tribe_events_virtual_show_embed_to":[],"_tribe_events_virtual_show_on_event":"","_tribe_events_virtual_show_on_views":"","_tribe_events_virtual_url":"","footnotes":"","_tec_slr_enabled":"","_tec_slr_layout":""},"tags":[],"tribe_events_cat":[23,22],"coauthors":[301],"class_list":["post-30101","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-evenements","tribe_events_cat-seminaires","cat_evenements","cat_seminaires"],"acf":[],"ticketed":false,"_links":{"self":[{"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tribe_events\/30101","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tribe_events"}],"about":[{"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/types\/tribe_events"}],"author":[{"embeddable":true,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/users\/174"}],"version-history":[{"count":2,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tribe_events\/30101\/revisions"}],"predecessor-version":[{"id":30103,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tribe_events\/30101\/revisions\/30103"}],"wp:attachment":[{"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/media?parent=30101"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tags?post=30101"},{"taxonomy":"tribe_events_cat","embeddable":true,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/tribe_events_cat?post=30101"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/lpg-umr6112.fr\/en\/wp-json\/wp\/v2\/coauthors?post=30101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}