Andean orogenic signature in the Quaternary sandy barriers of Southernmost Brazilian Passive Margin – Paradigm as a source area

Multiple source provenance of sediments and submarine fan formation are herein investigated based on Quaternary sandy barriers of the Brazilian Southernmost Coastal Plain. LA-ICP-MS dating on 1625 detrital zircons from marine and aeolian facies sands of four successive lagoon-barrier systems are analyzed. The characterization of Archean to Pleistocene zircons into a younger Andean (22 ± 4 Ma to 1 ± 1 Ma, 48 from 1625), Mesozoic to Paleozoic, and Mesoproterozoic (479 from 1622) populations suggest that the main feeding of sediments to the coastal plain occurred through the La Plata River drainage system. The significant contribution of sediments is transported from the mouth of La Plata River northward by longshore circulation (littoral drift). Minor contributions are also recognized as. a farther source associated with the Patagonia drainage and nearby source related to the Uruguay/Rio Grande do Sul Shield and the Paraná Basin, drained by the Camaquã and Jacuí rivers. The latter one is recognized by the contribution from Neoproterozoic to Early Paleozoic, and some Paleoproterozoic and Archean zircon grains. The definition of the sources of clastic sediments allows inferences about the origination of Rio Grande Fan where both the cold Falkland and the warm Brazil currents played a major role. [Display omitted] •Andean zircons transported to the eastern Brazilian Coast by littoral drift currents.•Multiple source provenance of sediments in the Rio Grande do Sul coastal plain.•Major contribution through the Rio de la Plata River distant ca. 600 km from the RGS coastal plain.•Precambrian zircons are mostly derived to neighbor basement rocks of the Sul-Rio-Grandense Shield.•Inferences about the Rio Grande Fan sedimentation due to interaction cold and warm currents.