Provenance of sandstones in the Parnaíba Basin through detrital zircon geochronology

Abstract

Abstract This paper obtains numerous U–Pb detrital zircon ages obtained from the Paleozoic–Triassic sandstones of the Parnaíba Basin. The resulting spectra enable us to distinguish three common age populations: Paleoproterozoic, Stenian–Tonian (mainly between 1100 and 900 Ma) and Late Neoproterozoic. Minor contributions are observed from Archean, Paleozoic (mainly Cambrian) and Mesoproterozoic sources. Differences are only highlighted by variances in the relative abundances of each age population within the stratigraphic units. The presence of metamorphic phases, schists clasts and some diagnostic heavy minerals suggest that the Neoproterozoic mobile belts to the east and west of the basin are potential source areas. The erosion of metasedimentary rocks exposed in these provinces could explain the Paleoproterozoic and Stenian–Tonian age populations found in the sandstones. The Late Neoproterozoic ages, in turn, are not relevant in the metasedimentary sequences, requiring that the voluminous granitic magmatism mainly exposed in the Borborema Province had directly participated as a primary source of the detritus. The maintenance of common age spectra leads to two (not exclusive) hypotheses: the long-term denudation of the source areas and/or intrabasinal recycling, which can be considered in future investigations on the sedimentary and tectonic evolution of the Parnaíba Basin.