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

Abstract

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