Triassic continental rifting of Pangea: direct evidence from the Alpujarride carbonates, Betic Cordillera, SE Spain

Evidence is presented for Triassic rift-related palaeo-structures from the Alpujarride Complex carbonates of the Betic Cordillera, SE Spain. Direct evidence of syn-sedimentary extensional tectonics is provided by the recognition of a macro- to meso-scale normal fault system overstepped by younger strata. Most of the faults define domino-like horst and graben structures. The faults are associated with an expanded syn-rift sedimentary prism in which soft-sediment deformation, gravity-flow deposits and unconformities are widely developed. Syn-tectonic mafic igneous intrusions have also been identified. The age of this phase of extension is well constrained as Ladinian-Carnian (c. 237 – 216 Ma). From a palaeotectonic and palaeogeographic standpoint, the thick Triassic carbonates of the Betic Internal Zone and Southern Apennine (Northern Calabria) occupied a belt with elevated subsidence connecting the Neo-Tethys rifting to the east and the eastern North American rift system to the west. Their carbonate facies, intermediate between classical Alpine-type and Germanic-type facies, recorded the main episodes of rifting affecting Central Pangea.