Origin of turbidites in deep Lake Geneva (France–Switzerland) in the last 1500 years

Article Article scientifique Article Origin of turbidites in deep Lake Geneva (France–Switzerland) in the last 1500 years eng 2015 author Kremer Katrina 716443 author Corella Juan Pablo 757350 author Adatte Thierry 735091 author Garnier Emmanuel 818835 author Zenhäusern Gregor author Girardclos Stéphanie 40596 1455-1465 10.2110/jsr.2015.92 1527-1404 http://jsedres.geoscienceworld.org/content/85/12/1455.abstract Turbidites in lacustrine sediments are commonly used to assess the frequencies of flood events and/or earthquakes. Understanding the origin of those deposits is key to adequately assess the sources and triggers of such events in large lacustrine systems. Ca/Ti X-ray fluorescence core scanner and magnetic susceptibility values on sediment cores of the deep basin of Lake Geneva are used as a provenance indicator of the turbidites either from the Dranse or Rhone deltas or from the slopes not influenced by deltaic input. This tool is validated by mineralogical analyses (X-ray diffraction), major-, and trace-element geochemistry (X-ray fluorescence). Based on this discrimination method, the turbidites deposited in the central part of the deep basin can be classified regarding their origin. From all identified turbidites, four turbidites are chosen based on their large depositional area and volumes and are studied in more detail in order to better understand the processes leading to turbidite deposition in the deep basin. The age intervals of these turbidites were compared to the historical records of extreme events in the region of Lake Geneva. These turbidites can be related to extreme floods, earthquakes, and “spontaneous” delta collapses. The cause of two turbidites could not be identified precisely due to large dating intervals that did not allow attributing a specific historical event to the turbidite layer. Overall, this study provides a tool in classifying the turbidites in deep Lake Geneva and exemplifies that defining the cause of turbidites is complex although it remains a prerequisite for paleohydrology and paleoseismology studies. Turbidite Lake Geneva XRF Flood deposit Rhône Dranse Mineralogy History Delta collapse Sublacustrine mass movement Holocene Dewey 550 Dewey 333.7-333.9 Swiss National Science Foundation Quantifying human impact and recent climate change using clastic sediments from lacustrine records in western Switzerland 121666 CH Projects Swiss National Science Foundation Quantifying human impact and recent climate change using clastic sediments from lacustrine records in Western Switzerland (Phase 2) 146889 CH Projects Swiss National Science Foundation DYNAMITE: Dynamic Nankai Trough (Japan) and Swiss Molasse Basin: Investigating NeoTectonics, Paleo-Earthquakes and associated Geohazards 133481 CH Careers Swiss National Science Foundation 'Pump priming' a historical database of extreme natural events in Lake Geneva region 154263 CH Careers 18 Institut des sciences de l'environnement 0DB 42 Département des sciences de la Terre 154 false 943 ISE Climat 944 ISE Eau 945 ISE Energie 938 ISE Pôle Sciences 946 ISE Villes et territoires 753 Limnology and Environmental Geology 664 Limnology and Geomicrobiology Journal of sedimentary research 85 12 543bf6b2-8f96-4aff-a24f-a8afc97ed549 Article (Published version) Restricted article_Kremer_2015c.pdf 4721207 application/pdf restrictedAccess Centres et instituts / Institut des sciences de l'environnement Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre

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Origin of turbidites in deep Lake Geneva (France–Switzerland) in the last 1500 years	Journal of sedimentary research			2015	712	6

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Garnier, Emmanuel