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Article Dans Une Revue Scientific Reports Année : 2023

Ignition of the southern Atlantic seafloor spreading machine without hot-mantle booster

Nick Kusznir
  • Fonction : Auteur
Charles Masquelet
Paul Bellingham
  • Fonction : Auteur
Dieter Franke

Résumé

Abstract The source of massive magma production at volcanic rifted margins remains strongly disputed since the first observations of thick lava piles in the 1980s. However, volumes of extruded and intruded melt products within rifted continental crust are still not accurately resolved using geophysical methods. Here we investigate the magma budget alongside the South Atlantic margins, at the onset of seafloor spreading, using high-quality seismic reflection profiles to accurately estimate the oceanic crustal thickness. We show that, along ~ 75% of the length of the Early-Cretaceous initial spreading centre, the crustal thickness is similar to regular oceanic thickness with an age > 100 Ma away from hot spots. Thus, most of the southernmost Atlantic Ocean opened without anomalously hot mantle, high magma supply being restricted to the Walvis Ridge area. We suggest that alternative explanations other than a hotter mantle should be favoured to explain the thick magmatic layer of seaward dipping reflectors landward of the initial mid-oceanic ridge.
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Dates et versions

hal-04048287 , version 1 (29-03-2023)

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Paternité

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Daniel Sauter, Gianreto Manatschal, Nick Kusznir, Charles Masquelet, Philippe Werner, et al.. Ignition of the southern Atlantic seafloor spreading machine without hot-mantle booster. Scientific Reports, 2023, 13 (1), pp.1195. ⟨10.1038/s41598-023-28364-y⟩. ⟨hal-04048287⟩
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