Potential role of lithospheric mantle composition in the Wilson cycle: a North Atlantic perspective

• Published in: Geological Society, London, Special Publications
• Main Authors: Chenin, Pauline, Picazo, Suzanne, Jammes, Suzon, Manatschal, G., Müntener, Othmar, Karner, Garry
• Other Authors: Géologie - océans - lithosphère - sédiments (IPGS) (IPGS-GEOLS), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Lausanne (UNIL), Texas State University, Now at ExxonMobil Exploration Company
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-01926207; https://hal.archives-ouvertes.fr/hal-01926207/document; https://hal.archives-ouvertes.fr/hal-01926207/file/Chenin%26al2018_GSL.pdf; https://doi.org/10.1144/SP470.10

International audience Although the Wilson cycle is usually considered in terms of wide oceans floored with normal oceanic crust, numerous orogens result from the closure of embryonic oceans. We discuss how orogenic and post-orogenic processes may be controlled by the size/maturity of the inverted basin. We focus on the role of lithospheric mantle in controlling deformation and the magmatic budget. We describe the physical properties (composition, density, rheology) of three types of mantle: inherited, fertilized and depleted oceanic mantle. By comparing these, we highlight that fertilized mantle underlying embryonic oceans is mechanically weaker, less dense and more fertile than other types of mantle. We suggest that orogens resulting from the closure of a narrow, immature extensional system are essentially controlled by mechanical processes without significant thermal and lithological modification. The underlying mantle is fertile and thus has a high potential for magma generation during subsequent tectonic events. Conversely, the thermal state and lithology of orogens resulting from the closure of a wide, mature ocean are largely modified by subduction-related arc magmatism. The underlying mantle wedge is depleted, which may inhibit magma generation during post-orogenic extension. These end-member considerations are supported by observations derived from the Western Europe–North Atlantic region.