Detrital zircon U-Pb ages of a late-Variscan Carboniferous succession associated with the Porto-Tomar shear zone (West Portugal): Provenance implications

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

“…The Triassic samples came from the basal units of the Silves Group (Conraria Formation in the Lusitanian Basin, AB1 and SC1 in Algarve and Alentejo basins), and comprise three samples from the Lusitanian Basin, one sample from the Alentejo Basin and two samples from the Algarve Basin. Pb detrital zircon data in this research complement and are discussed together with previously published detrital zircon data from coeval units, namely those reported for the Upper Pennsylvanian of the Buçaco Basin (Dinis et al, 2012) and the Triassic of the Lusitanian Basin (Pereira et al, 2016) and the Alentejo and Algarve basins (Pereira et al, 2017). Sample selection was undertaken so as to give a regional perspective on the paleogeographic conditions during the transition from Pangea amalgamation to fragmentation, encompassing: 1) the late Carboniferous and early Permian episodes of deformation associated with N-S and WNW-ESE shear zones and 2) the subsequent Triassic rifting in West and South Iberia.…”

“…In this study we present new U-Pb detrital zircon age data from a set of sedimentary basins on Western and Southern Iberia that formed during the transition from the final stages of Pangea amalgamation (Pennsylvanian) to early fragmentation (Permian-Triassic) ( Table 1). These new geochronology results are coupled with recently published data for the Triassic sequences of the Lusitanian (Pereira et al, 2016), Alentejo and Algarve basins (Pereira et al, 2017), and the Pennsylvanian of the Buçaco Basin (Dinis et al, 2012) of western and southern Iberia (Fig. 2).…”

“…9) and was also identified in the Pennsylvanian of the Buçaco Basin (Dinis et al, 2012). It may be related to crystalline rocks that presently crop out in several locations of western and central Iberia sedimentary rocks that lithologically resemble the PrecambrianCambrian Schist-Greywacke Complex (Talavera et al, 2012).…”

“…The detrital record of syn-to post-collisional basins has provided important information on the exhumation history and the sedimentary transport systems during orogenesis (Dinis et al, 2012;Pastor-Galán et al, 2013). This method has also been applied to the central and western Iberian basins associated with Pangea break-up, which show clear provenance changes attributed to changes in the paleoflow Sedimentary Geology xxx (2017) xxx-xxx ⁎ Corresponding author.…”

Heavy-mineral, mineral-chemical and zircon-age constraints on the provenance of Triassic sandstones from the Devon coast, southern Britain

“…The origin of the late Mesoproterozoic to early Neoproterozoic group is less certain, since the Brioverian metasediments do not contain this group (Miller et al, 2001;Samson et al, 2005), and crystalline rocks of this age do not appear to be present in the Armorican Massif (Roach et al, 1990). However, such zircons are found as detrital components of sediments in other parts of the Armorican Massif (Catalán et al, 2004;Dinis et al, 2012), and recycling from pre-existing sediment is therefore considered their most likely origin.…”