Assessing the impact of orogenic inheritance on the architecture, timing and magmatic budget of the North Atlantic rift system: a mapping approach

• Published in: Journal of the Geological Society
• Main Authors: Chenin, Pauline, Manatschal, Gianreto, Lavier, L.L., Erratt, Duncan
• Other Authors: Dynamique de la lithosphère et des bassins sédimentaires (IPGS) (IPGS-Dylbas), 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), Institute of Geophysics Austin (IG), University of Texas at Austin Austin, CEIBA project (Exxon Mobil)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: rift; hyperextended; tectonic; mapping; North Atlantic; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
• Online Access: https://hal.science/hal-01213215; https://hal.science/hal-01213215/document; https://hal.science/hal-01213215/file/Chenin%26al2015_unformatted.pdf; https://doi.org/10.1144/jgs2014-139

International audience In order to investigate the impact of orogenic inheritance on the characteristics of hyperextended rift systems we develop new mapping methods highlighting the first-order architecture and timing of hyperextended rifts, as well as the distribution of heterogeneities inherited from previous orogenies. We use these to characterize the North Atlantic rift system and adjacent areas affected by the Palaeozoic Caledonian and Variscan orogenies. Comparison of these maps demonstrates major differences in the behaviour of the North Atlantic rift relative to both orogens, the Variscan front appearing to be a major limit. Indeed, the rift cuts through the Caledonian orogen and parallels its structural grain, while it circumvents the core of the Variscides. In addition, rifting is protracted and polyphase, and breakup is magma-rich North to the Variscan front, as opposed to the South where a single, apparently continuous extensional event lead to magma-poor breakup in less than 50 Myr. These observations point to a major influence of orogenic inheritance on the characteristics of hyperextended rift systems. On the other hand, our study supports that rifts reactivate sutures corresponding to former large (> 2 000 km) oceans, while leaving sutures of small (< 500 – 1 000 km) oceanic basins little affected, suggesting a significant impact of the pre-orogenic histories on subsequent extensional processes.