Late Pleistocene to Middle Holocene paleoenvironmental changes based on diatom record in Salina del Bebedero (San Luis, Argentina)

This study analyzes the environmental changes that occurred in the western sector of the San Luis province (Argentina) during the Late Pleistocene to Middle Holocene period (approximately 12,600 to 3,600 years BP). The information provided by diatoms as paleobiological indicators is used for this analysis. We examined the lower 5 meters of the 10-meter-long SBIII core, which was recovered from the endorheic and hypersaline shallow lake known as Salina del Bebedero (33 degrees 20'S-66 degrees 45'W, 380 m a.s.l.).The observed peaks of relative abundance of the planktonic diatom Cyclotella choctawhatcheeana suggest episodes of substantial water supply to the shallow lake from the Andes mountains via the Desaguadero river. These episodes were interspersed with periods of low water levels, resulting in very shallow to marsh environments characterized by the presence of epiphytic and benthic diatoms. Furthermore, we discuss and integrate the inferred paleoenvironmental information obtained from the diatom records, along with data from other proxies such as pollen and sedimentology. This integration aims to enhance the previously developed paleoenvironmental model for the region, covering the period between approximately 12,600 and 3,600 years BP.Overall, this research significantly contributes to the understanding of diatom assemblages in hypersaline lacustrine systems of the eastern Andes throughout the studied period, revealing the importance of certain taxa as indicators of wetter conditions during the early Holocene and in more recent stages within this timeframe. Additionally, this study aims to expand our existing knowledge of diatoms biodiversity in this province.

Automated summary

This study analyzes the environmental changes in the western sector of San Luis province in Argentina during a specific time period. The study focuses on the analysis of diatoms as paleobiological indicators and examines the sediment core from a hypersaline shallow lake. The research enhances the understanding of diatom assemblages in this region and contributes to the knowledge of diatoms biodiversity.