Estudio geofísico de la corteza oceánica de la Cuenca Canaria (Atlántico Centro-Oriental)

C.R. RANERO, E. BANDA

Abstract


The combined study of single- and multi-channel seismic reflection data allow us to understand the structure of the Canary Basin oceanic crust and their relationship with the seafloor spreading history and main tectonic features formed during Mesozoic times on the Central Atlantic. The seismic image of the oceanic crust is very variable, with an irregular to smooth basement topography. The crustal inner reflectivity is also very variable, from transparent to highly reflective, depending on the segment. Where the basement topography is irregular, the main features are strongly dipping isolated reflections from the upper-middle crust, eventually reaching the lower crust. By the contrary, in areas with smooth basement topography, reflectivity is largely extended, particularly in the lower crust. Crustal thickness can be estimated along most of the multi-channel seismic reflection profiles, being delimited by sub-horizontal reflections in the crust-mantle boundary. The crustal thickness is generally of 2.0 S TWTT, although in areas with smooth topography values between 2.5 and 3 s can be reached. The geodynamic setting where the Canary Basin formed could explain the variability of its crustal structure. The oceanic crust with irregular topography and disperse reflectivity should have been formed in a typical slow spreading ridge with an important extensional tectonic activity. By the other hand, oceanic crust with smooth topography and abundant reflectivity should have been formed in a slow spreading ridge where crust-generating processes were modified by the nearest presence of a mantle thermal anomaly.


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