Stacked Magma Lenses Beneath Mid‐Ocean Ridges: Insights From New Seismic Observations and Synthesis With Prior Geophysical and Geologic Findings - HAL Accéder directement au contenu
Article dans une revue Journal of Geophysical Research : Solid Earth Année : 2021

Stacked Magma Lenses Beneath Mid‐Ocean Ridges: Insights From New Seismic Observations and Synthesis With Prior Geophysical and Geologic Findings

Suzanne Carbotte
Adrien Arnulf
Gillean Arnoux

Résumé

Abstract Recent multi‐channel seismic studies of fast spreading and hot‐spot influenced mid‐ocean ridges reveal magma bodies located beneath the mid‐crustal Axial Magma Lens (AML), embedded within the underlying crustal mush zone. We here present new seismic images from the Juan de Fuca Ridge that show reflections interpreted to be from vertically stacked magma lenses in a number of locations beneath this intermediate‐spreading ridge. The brightest reflections are beneath Northern Symmetric segment, from ∼46°42′‐52′N and Split Seamount, where a small magma body at local Moho depths is also detected, inferred to be a source reservoir for the stacked magma lenses in the crust above. The imaged magma bodies are sub‐horizontal, extend continuously for along‐axis lengths of ∼1–8 km, with the shallowest located at depths of ∼100–1,200 m below the AML, and are similar to sub‐AML bodies found at the East Pacific Rise. At both ridges, stacked sill‐like lenses are detected beneath only a small fraction of the ridge length examined and are inferred to mark local sites of higher melt flux and active replenishment from depth. The imaged magma lenses are focused in the upper part of the lower crust, which coincides with the most melt rich part of the crystal mush zone detected in other geophysical studies and where sub‐vertical fabrics are observed in geologic exposures of oceanic crust. We infer that the multi‐level magma accumulations are ephemeral and may result from porous flow and mush compaction, and that they can be tapped and drained during dike intrusion and eruption events.
Loading...

Dates et versions

halshs-04257691, version 1 (25-10-2023)

Identifiants

Citer

Suzanne Carbotte, Milena Marjanović, Adrien Arnulf, Mladen Nedimović, Juan Pablo Canales, et al.. Stacked Magma Lenses Beneath Mid‐Ocean Ridges: Insights From New Seismic Observations and Synthesis With Prior Geophysical and Geologic Findings. Journal of Geophysical Research : Solid Earth, 2021, 126 (4), ⟨10.1029/2020JB021434⟩. ⟨halshs-04257691⟩
3 Consultations
0 Téléchargements
Dernière date de mise à jour le 05/05/2024
comment ces indicateurs sont-ils produits

Altmetric

Partager

Gmail Facebook Twitter LinkedIn Plus