Mid-Norwegian continental margin magmatism and Paleogene global climate change: An overview of the upcoming International Ocean Discovery Program (IODP) Expedition 396

Continental breakup between Greenland and NW Europe in the Paleogene was associated with transient massive magmatism and a global hot-house named the Paleocene-Eocene Thermal Maximum (PETM). The International Ocean Discovery Program (IODP) Expedition 396 will study the cause of this magmatism and its climate implication by drilling up to nine boreholes across the Vøring and Møre continental margins in August-September 2021. The expeditions will be conducted in conjunction with ICDP project PVOLC which plan to drill the Paleogene sequences in a more distal setting in Denmark in 2022. The NE Atlantic conjugate volcanic rifted margins are characterized by extensive break-up magmatism recorded by basalt flows, volcanogenic sediments, magmatic underplates, and intrusive complexes in sedimentary basins and the crust. Massive injection of magma into organic-rich sedimentary basins is a likely mechanism for triggering short-term global warming during the Paleocene-Eocene Thermal Maximum (PETM). A key objective of this expedition is to document the nature and explain the causes and consequences of excess magmatism during breakup as the large amount of magmatism cannot be easily be explained by passive decompressional melting of sub-lithospheric mantle with a normal potential temperature. New constraints on 1) melting conditions, 2) timing of magmatism, 3) spatial and temporal variations, 4) eruption environment, 5) sedimentary proxy data, and 6) temporal resolution of magmatism and climate change events are required to resolve current controversies. Systematic IODP drilling is a way to provide these constraints and will allow the development of a quantitatively testable framework for volcanic rifted margin formation and consequences for global climate change. New 3D seismic data collected by the industry and academia during the past few years have provided unique imaging of the basalt and sub-basalt sequences and allowed for optimal planning of the drill sites for scientific purposes. Additional holes are located along and outboard of the continent-ocean boundary to constrain the temporal evolution of the breakup magmatism. Two of the scientific drilling aims of this cruise are to core Paleogene sequences across the PETM and to drill one of the thousands of hydrothermal vent complexes to attain a proximal record of NAIP activity. This will give vital information on the proximal environmental disturbances during the NAIP emplacement.