Provenance and sedimentary pathways on the largest inland aeolian system in Brazil: Insights from heavy-mineral analysis in Xique-Xique dune field

The Xique Xique aeolian system is the largest Quaternary interior dune field in Brazil, comprising areas on both margins of the São Francisco River. With a sediment volume of more than 600 km³, the origin of this large amount of sand and its possible sources are issues that have drawn the attention of researchers in the last century. We aim to determine whether the dune fields on each side of the river have distinct sources, understand deposition mechanisms, and investigate variations in sedimentary provenance over time. Through a multi-proxy analysis of granulometry, heavy minerals assemblages, and tourmaline and zircon varieties, we investigated the connection between this aeolian system and the river, regarding source areas and sedimentary pathways. The data obtained show more similarities between the dune fields in both margins than differences. Statistical analysis indicates that, on both margins, fluvial terraces acted as primary source of sediments, exhibiting the intrinsic connection among the dunes fields and the river. There are no signs of mineralogy variation over time, only a lack of unstable minerals in the older deposits. The Xique Xique aeolian system appears to be highly influenced by the river past, climate and wind direction.