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Crustal decoupling and intracrustal flow beneath domal exhumed core complexes, Betics (SE Spain)
Author(s) -
MartinezMartinez J. M.,
Soto J. I.,
Balanyá J. C.
Publication year - 1997
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.1997.tb00017.x
Subject(s) - geology , crust , metamorphic core complex , tectonics , seismology , anticline , extensional definition , upper crust , paleontology , petrology , geomorphology
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.