23 Crustal Cross Sections from the Western North America Cordillera and Elsewhere—Implications for Tectonic and Petrologic Processes (Posters)
KINEMATICS OF THE BETIC-RIF ARC FROM CRUSTAL CROSS-SECTIONS
Paper number: 23-3
Program: THEME SESSIONS
Time: 9:00 AM – 5:00 PM
Authors
Abstract
During the formation of the external thrust belt, the Alboran Domain itself experienced a kinematically complex pattern of extensional deformation, which may have resulted from the removal of lithospheric mantle beneath it at about 24 Ma, following Eocene crustal thickening. Rapid NNE-directed extension and shear between 22 and 19 Ma thinned an early thrust stack as much as 50 km thick to between 5 and 10 km thickness, creating a stack of extensional allochthons separated by sub-horizontal detachment faults.
Subduction of the leading edge of the Iberian margin beneath the advancing edge of the Alboran Domain at about 19 Ma, and rapid exhumation completed by 12 Ma, created a large metamorphic dome beneath the previously extended and now overthrust Alboran Domain, bounded by an extensional detachment with predominantly W-directed shear sense. Dextral shear related to thrusting of the Alboran Domain over the Iberian margin rotated earlier mylonitic stretching lineations and normal-sense slip vectors in the Alboran Domain by variable amounts towards E.