Lithospheric delamination in the core of Pangea: Sm-Nd insights from the Iberian mantle. G. Gutiérrez-Alonso, J. B. Murphy, J. Fernández-Suárez, A. B. Weil, M. P. Franco, J. C. Gonzalo, 2011, Geology, 39, 155-158. DESCARGAR-DOWNLOAD.
Delamination of continental lithosphere in the core of active collisional orogens is a well established process; however, evidence for its occurrence in ancient orogenic belts is less obvious. The contrasting Sm-Nd isotopic signature between pre- and post- Middle Permian mantle-derived mafic rocks from under the Iberian Massif suggests that most, but not all, of the sub-continental lithospheric mantle (SCLM) was replaced in latest Carboniferous to Permian times. Mantle replacement happened during and after the bending of the Variscan orogenic belt into the horseshoe-shaped Iberian-Armorican Arc orocline. Delamination of thickened continental lithosphere in the core of the orocline triggered replacement of the ancient SCLM, thereby providing an explanation for the contrasting Sm-Nd isotopic characteristics of pre- and post- ca. Middle Permian mafic rocks.