Abstract
The Moho—the boundary between crust and mantle first discovered by A. Mohorovicic1—is the main seismic marker in the continental lithosphere. The seismic nature of this interface, in terms of its position, topography, smoothness and continuity, may preserve imprints of the regional geodynamic evolution of the lithosphere. Here we report the results of a wide-angle seismic profiling experiment across the western Alps, which allows us to draw a cross-section of the Moho across this mountain belt. A tight sampling of this deep reflector shows abrupt changes in its depth and dip. The root zone of the chain (the zone of maximum crustal thickness) is well defined, with a 55-km-deep crust–mantle boundary. The Moho under the western Po plain is also clearly seen, and a shallow reflective structure is mapped under the Briançonnais zone in the 25–30 km depth range. This structure, if interpreted as lower-crustal or upper-mantle material, would support the hypothesis of a flaking of the lithosphere under the western Alps2,3.
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CROP Deep Seismic Sounding Group A new picture of the Moho under the western Alps. Nature 337, 249–251 (1989). https://doi.org/10.1038/337249a0
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DOI: https://doi.org/10.1038/337249a0
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