Origin of the Permian-Triassic Iberian Basin, central-eastern Spain

Abstract

The Iberian Basin was an intracratonic rift basin in central-eastern Spain developed since Early Permian times. The basin boundary faults were normal, listric faults controlling an asymmetric extension propagating northeast with time.Hercynian or older lineaments controlled the orientation of the Iberian Basin and extension was accommodated basically in the hanging wall block by the formation of secondary grabens and a central high. The basin was related with the coeval Ebro, Catalan and Cuenca-Mancha Basins and their connections are discussed.Subsidence curves show that the Early Permian-Early Jurassic period of extension can be subdivided into three rifting episodes and a flexural one. Extension factor increases from 1.17 in the northwest to 1.29 near the Mediterranean coast.The increasing extension rate was accommodated by transfer faults trending NNE-SSW, more important in the Levante area. The rift evolution is intermittent and seems to reflect distinct stress fields.The collapse of the late Hercynian orogen and related increased heat flux, extension and rifting is the most probable origin of the Iberian Basin and related basins. The origin of the Catalan and the Valencia-Prebetic Basins is related to the southwards migration of the Hesse-Burgundy Rift along the eastern margin of the Iberian Microplate.

Oblique strain partitioning and transpression on an inverted rift: The Castilian Branch of the Iberian Chain

“…The orientation of the active faults during this period is N140E (as is the Somolinos Fault, Fig. 6A), but it is also N170E (As suggested also by Arche and Lopez Gomez, 1996) and NE-SW, which results in horst rhomboids producing r ® N ® x stratigraphic highs. These orientations of simultaneously active normal faults probably indicate extension under triaxial conditions, rather than successive extensional phases, and roughly respond to a Shm in located in a NE-SW direction (Figs.…”

Stratigraphical and palaeogeographical significance of the continental sedimentary transition across the Permian–Triassic boundary in Spain

“…The general interpretation of the western Tethys in this figure is based on Ziegler and Stampfli (2001), Ziegler (1988), Stampfli and Borel (2002) and Ford and Golonka (2003). Some of the basins of Iberia were the result of reactivation of ancient Hercynian faults (Arthaud and Matte, 1977;Alvaro et aI., 1979;Ziegler, 1988;Arche and L6pez-G6mez, 1996), representing the initial phase of post-Variscan plate reorganization. This initial break-up of Pangea was related to a series of strike-slip fuults that dissected the Variscan foldbelt and its associated foreland areas.…”

“…After minor faulting induced by transtensional defonnation during Stephanian-Autunian times, Iberia, as well as part of NW Africa, fonned a coherent positive area while major grabens that had already started to form during the deposition of the Rotliegendes occupied the area from Poland to the Black Sea. The seas of the End Permian advanced westward along the axes of these pre-existing rift systems, while basins in Iberia were filled by thick, red beds sequences of continental origin (Sopefia et al., 1988;Van Wees et aI., 1998;Arche and L6pez-Gomez, 1999 (Arche and L6pez-G6mez, 1996). Different isolated small highs arose along the elevated flanks of the main troughs.…”

“…The evolution of this rift system was related to the initial break-up of Pangea and the southward propagation of the Norwegian-Greenland sea rift and development of the Tethys rift systems. As the result of this widespread extensional tectonics, the CantabrianPyrenean, Catalonian and Iberian basins were created and began their development during the Thuringian (Arche and L6pez-G6mez, 1996). The opening and evolution of these basins was not synchronous.…”

Temporal and spatial variations in tectonic subsidence in the Iberian Basin (eastern Spain): inferences from automated forward modelling of high-resolution stratigraphy (Permian–Mesozoic)

“…nent of the vertical movements indicate that this is a main phase of increased subsidence rates marked by lithospheric stretching fa ctors of 1.1-1.3 (Salas and Casas, 1993;Van We es and Stephenson, 1995;Arche and L6pez-G6mez, 1996). In Early Jurassic and Mid dle Jurassic times subsidence rates relatively decrease and clear indications for fa ulting are absent, suggest ing tectonic quiescence.…”