RT Journal Article
T1 Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana
A1 Díez Fernández, Rubén
A1 Jiménez Díaz, Alberto
A1 Arenas Martín, Ricardo
A1 Pereira, M. Francisco
A1 Fernández Suárez, Javier
AB The Calzadilla Ophiolite is an ensemble of mafic and ultramafic rocks that represents the transition between lower crust and upper mantle of a Cadomian (peri‐Gondwanan) fore arc. Mapping and structural analysis of the ophiolite demonstrates that it was obducted in latest Ediacaran times, because the Ediacaran‐Early Cambrian sedimentary series (Malcocinado Formation) discordantly covers it. The ophiolite and emplacement‐related structures are affected by Variscan deformation (Devonian‐Carboniferous), which includes SW verging overturned folds (D1) and thrusts (D2), upright folds (D3), extensional faults (D4), and later faults (D5). These phases of deformation are explained in the context of Variscan tectonics as the result of the progressive collision between Gondwana and Laurussia. Qualitative unstraining of Variscan deformation reveals the primary geometry of Ediacaran‐Cambrian structures and uncovers the generation of east verging thrusts as responsible for the primary obduction of the Calzadilla Ophiolite. Restoration of planar and linear structures associated with this event indicates an Ediacaran, east directed obduction of the ophiolite, that is, emplacement of the Cadomian fore arc onto inner sections of the northern margin of Gondwana. According to regional data, the obduction separates two extension‐dominated stages in the tectonic evolution of the African margin of northern Gondwana preserved in southern Europe. Preobduction extension brought about the onset and widening of fore‐arc and back‐arc basins in the external part of the continent, while postobduction extension facilitated the formation of extensional migmatitic domes, an oceanward migration of back‐arc spreading centers across peri‐Gondwana, and the eventual opening of a major basin such as the Rheic Ocean.
PB American Geophysical Union
SN 0278-7407, ESSN: 1944-9194
YR 2019
FD 2019-01
LK https://hdl.handle.net/20.500.14352/13190
UL https://hdl.handle.net/20.500.14352/13190
LA eng
NO Ministerio de Economía, Industria y Competitividad (MINECO)
DS Docta Complutense
RD 5 abr 2025