Evolution of the accretion processes along the Mid-Atlantic Ridge north of the Azores since 5.5 Ma: An insight into the interactions between the ridge and the plume

Marcia Maia (1) , Jean Goslin (1) , Pascal Gente (1)

1 LDO - Domaines Océaniques

High-resolution bathymetry and gravity data north of the Azores Plateau show that this part of the North Mid-Atlantic Ridge is presently undergoing a phase of weak crustal production and magmatism. Most of the ridge segments are small and short-lived, suggesting a disrupted and highly variable accretion regime since anomaly 3A. The influence of the nearby plume appears to be relatively minor and corresponds more to a weak thermal signal than to any major input of plume material and increased crustal production at the axis. A period of increased magmatism was identified at the southern limit of the study area (near 40°N) around anomaly 5. This magmatic "pulse" caused the emplacement of a topographic high, probably underlain by a thickened crust. This pulse probably marks the northernmost and last significant arrival of material from the Azores plume to the MAR axis

Mots clés: Midocean ridge processes; Seafloor morphology; geology; and geophysics

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Milieux et Changements globaux

Marcia Maia, Jean Goslin, Pascal Gente. Evolution of the accretion processes along the Mid-Atlantic Ridge north of the Azores since 5.5 Ma: An insight into the interactions between the ridge and the plume. Geochemistry, Geophysics, Geosystems, 2007, 8 (3), pp.Q03013. ⟨10.1029/2006GC001318⟩. ⟨hal-00140487⟩