Constraints on the geodynamic evolution of the Africa-Iberia plate margin across the Gibraltar Strait from seismic tomography

• Published in: Di xue qian yuan. Vol. 6; no. 1; pp. 39 - 48
• Main Authors: Monna, S., Argnani, A., Cimini, G.B., Frugoni, F., Montuori, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2015
• Subjects: Africa–Iberia plate margin; Lithospheric subduction; Mantle upwelling; Teleseismic tomography; Velocity anomaly; 上地幔速度结构; 动力学演化; 图像显示; 地震层析成像; 板块边缘; 直布罗陀海峡; 速度异常; 非洲; Teleseismic tomography; Velocity anomaly; Lithospheric subduction; Mantle upwelling; Africa–Iberia plate margin
• ISSN: 1674-9871
• DOI: 10.1016/j.gsf.2014.02.003

Geophysical studies point to a complex tectonic and geodynamic evolution of the Alboran Basin and Gulf of Cadiz. Tomograpbic images show strong seismic waves velocity contrasts in the upper mantle. The high velocity anomaly beneath the Alboran Sea recovered by a number of studies is now a well estab- lished feature. Several geodynamic reconstructions have been proposed also on the base of these images. We present and elaborate on restllts coming from a recent tomography study which concentrates on both the Alboran and the adjacent Atlantic region. These new results, while they confirm the existence of the fast anomaly below the Alboran region, also show interesting features of the lithosphere-asthenosphere system below the Atlantic. A high velocity body is imaged roughly below the Horseshoe Abyssal plain down to sub-lithospheric depths. This feature suggests either a possible initiation or relic subduction. Pronounced low velocity anomalies pervade the upper mantle below the Atlantic region and separate the lithospheres of the two regions. We also notice a strong change of the upper mantle velocity structure going from south to north across the Gorringe Bank. This variation in structure could be related to the different evolution in the opening of the central and northern Atlantic oceans.