1 The Early Toarcian oceanic anoxic event: Paleoenvironmental and paleoclimatic change 1 across the Alpine Tethys (Switzerland) 2 Alicia Fantasia 1 *, Karl B. Föllmi 1 , Thierry Adatte 1 , Jorge E. Spangenberg 2 , Jean-Carlos 3 Montero-Serrano 3,4 4 1 Institute of Earth Sciences (ISTE), University of Lausanne, 1015 Lausanne, Switzerland (*corresponding author: 5 alicia.fantasia@unil.ch) 6 2 Institute of Earth Surface Dynamics (IDYST), University of Lausanne, 1015 Lausanne, Switzerland 7 3 Marine Sciences Institute (ISMER), University of Quebec in Rimouski, Rimouski, Quebec, G5L 3A1, Canada 8 4 GEOTOP Research Center, C.P. 8888, Montreal, QC H3C 3P8, Canada 9 10 Abstract 11 Paleoenvironmental and paleoclimatic change associated with the Toarcian oceanic 12 anoxic event (T-OAE) was evaluated in five successions located in Switzerland. They 13 represent different paleogeographic settings across the Alpine Tethys: the northern shelf 14 (Gipf, Riniken and Rietheim), the Sub-Briançonnais basin (Creux de l’Ours), and the 15 Lombardian basin (Breggia). The multi-proxy approach chosen (whole-rock and clay 16 mineralogy, phosphorus, major and trace elements) shows that local environmental conditions 17 modulated the response to the T-OAE across the Alpine Tethys. On the northern shelf and in 18 the Sub-Briançonnais basin, high kaolinite contents and detrital proxies (detrital index, Ti, Zr, 19 Si) in the T-OAE interval suggest a change towards a warmer and more humid climate 20 coupled with an increase in the chemical weathering rates. In contrast, low kaolinite content 21 in the Lombardian basin is likely related to a more arid climate along the southern Tethys 22 margin and/or to a deeper and more distal setting. Redox-sensitive trace-element (V, Mo, Cu, 23 Ni) enrichments in the T-OAE intervals reveal that dysoxic to anoxic conditions developed on 24 the northern shelf, whereas reducing conditions were less severe in the Sub-Briançonnais 25