Margin-to-Margin Seafloor Spreading in the Eastern Gulf of Aden: A 16 Ma-Long History of Deformation and Magmatism from Seismic Reflection, Gravity and Magnetic Data

Abstract

In this paper we present and analyze spreading-parallel seismic transects that image the oceanic crust in the eastern Gulf of Aden, from the Oman to the Socotra margins, across the active Sheba mid-oceanic ridge and between the Socotra-Hadbeen and Eastern Gulf of Aden Fracture Zones. The correlation of potential field data sets and gravity modelling allow us to document the spreading history of this oceanic basin from the onset of seafloor spreading ∼16 Ma-ago to the present. Two main oceanic sub-domains display distinct structural characteristics associated with different magmatic budgets at this mid-ocean ridge. In addition, we document the occurrence of a magmatic pulse at the Sheba Ridge around 11 Ma leading to the construction of a magmatic plateau in the western part of the studied area. This event led to substantial deformation and additional magmatism in previously formed oceanic crust. It could be related to an off-axis magmatic event previously identified in the adjacent Sheba segment, itself possibly related to the Afar plume.

Lithospheric Structure of the Red Sea Based on 3D Density Modeling: A Contrasting Rift Architecture

“…In contrast to the central‐southern Red Sea, the Gulf of Aden margins appear extremely short (e.g., Autin et al., 2010). Here, the basin deeps abruptly close to the shoreline (Figure 3a) and magnetic isochrones (Fournier et al., 2010) and seismic profiles (Gillard et al., 2021) suggest a nearly margin‐to‐margin seafloor spreading. Bellahsen et al.…”

“…In contrast to the central-southern Red Sea, the Gulf of Aden margins appear extremely short (e.g., Autin et al, 2010). Here, the basin deeps abruptly close to the shoreline (Figure 3a) and magnetic isochrones (Fournier et al, 2010) and seismic profiles (Gillard et al, 2021) suggest a nearly margin-to-margin seafloor spreading. Bellahsen et al (2013) inferred that the thermal anomaly of the Afar plume may helped in the localization and the development of the rift-parallel faulting in the western Gulf of Aden.…”

Evolution of the East African Rift System from trap-scale to plate-scale rifting

“…Furthermore, the plate-motion change of the Capricorn plate, attributed to an increasing buoyancy of the Réunion plume flux at 11 Ma (Iaffaldano et al, 2018), could instead result from the main change of the dynamics of the EARS in tandem with the possible increase of the sub-lithospheric mantle flux. The magmatic pulse recently evidenced along the Sheba ridge at 11 Ma (Gillard et al, 2021) could also have an origin closely linked to the evolution of the EARS. We finally suggest that the source of extension stresses affecting the African plate progressively evolved from a dominant far-field origin to prevailing GPE variations and a diverging Couette-type basal shear, thus changing of the dynamics of the EARS from trap-scale to plate scale rifting.…”

Using Large-Size Three-Dimensional Marine Electromagnetic Data for the Efficient Combined Investigation of Natural Hydrogen and Hydrocarbon Gas Reservoirs: A Geologically Consistent and Process-Oriented Approach with Implications for Carbon Footprint Reduction

“…So far, it is known that methane and native hydrogen are produced in the competing processes of serpentinization and magmatism in slow-and ultraslow-spreading mid-ocean ridges, continental margins, and forearc settings of the subduction zones [21,[30][31][32]. Serpentinization occurs when ultramafic rocks react chemically with invading seawater (or meteoric water) without biotic mediation, generating hydrogen, which can reduce carbon dioxide to methane.…”