Blackwell Publishing Journal Backfiles 1879-2005
The Sierra Nevada core, located in the Betic hinterland, features a N-S large-scale open antiform with a central relatively uplifted highly extended domain placed between two less extended domains (in the east and in the west) dipping eastwards and westwards, respectively. The core-bounding detachment system formed during the Serravallian (15–11 Ma) in an episode of ENE-WSW extension. The ESCI-Beticas 2 deep seismic reflection profile, a transect through the core, shows a highly reflective deep crust overlying a subhorizontal Moho, and a fairly transparent upper crust and upper mantle. The lack of Moho relief beneath this area, with differential values for supra-crustal thinning, suggests a mechanism of intracrustal isostatic compensation. Surface geology data together with seismic imaging indicate intracrustal flow and upward doming as a response to footwall unloading accompanying the middle Miocene supracrustal extension. A prominent mid-crustal reflector (MCR) is deemed to represent a decoupling zone between the upper and the deep crust. Subsequent N-S shortening and associated folding occurred in the late Miocene. The interference pattern of this folding over the middle Miocene core produced the current E–W dome-shaped tectonic windows where the deepest complex of the Betic hinterland crops out.
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