The Rio Grande Rise and Jean Charcot Seamount Chain - microcontinents or the trail of the Tristan-Gough hotspot? Cruise No. MSM 82, 18 March 2019 - 24 April 2019, Montevideo (Uruguay) - Montevideo (Uruguay), RIOGRANDE

• Main Authors: Geissler, Wolfram, Krumm, Stefan, O'Connor, John, Geldmacher, Jörg, Altenbernd, Tabea, Homrighausen, Stephan, Geils, Jonah, Hoyer, Patrick, Lehmann, Carsten, Shearing, Jennifer
• Format: Report
• Language: English
• Published: Gutachterpanel Forschungsschiffe 2019
• Subjects: Charcot; Gough; Kongsberg; Tristan; Uruguay; South Atlantic Ocean
• Online Access: https://oceanrep.geomar.de/id/eprint/48596/; https://oceanrep.geomar.de/id/eprint/48596/1/MSM82_CR.pdf; https://doi.org/10.2312/cr_msm82

Rio Grande Rise: microcontinent, mantle plume, or both? The origin of the Rio Grande Rise (RGR) is debated. It could represent a continental sliver, or a large igneous province that was emplaced in the late Cretaceous after the opening of the South Atlantic Ocean. The interplay between the RGR and the nearby Jean Charcot Seamount Chain (JCSC) is also not understood. Cruise MSM82 dredge sampled rocks from the JCSC and the RGR and measured two seismic refraction profiles across the RGR where it is bisected by a long rift graben. A range of geophysical data were also collected during much of the expedition, including magnetics, gravity, bathymetry (Kongsberg EM 122), sub-bottom profiling (ATLAS PARASOUND DS P70) and ADCP data. The combination of geochronological, geochemical and geophysical information will provide a unique window on the relation between mantle plumes, continental fragments and the evolution of large igneous provinces.