Multivariate analysis to reveal patterns of trace elements in Mono Lake carbonates

MARA MATIC; FERNANDO J GOMEZ; ALEXANDRA RODLER

Leysin

Conferencia; Microbialites: Formation, Evolution and Diagenesis conference. 2023 MFED; 2023

UNIVERSITÉ LAUSSANE. UNIVERSITÉ DE GENEVE. UNIVERSITÉ FREIBURG. ETH ZURICH

Mono Lake chimneys formed by mineral precipitation offer a unique geological record that sheds light on ecosystem dynamics, physicochemical processes, hydrological and climate evolution within lake systems. Consequently, there has been a growing interest in investigating the biogeochemical processes involved in the formation of carbonate chimneys around sublacustrine vents. This may be useful in the understanding the record of ancient or even extraterrestrial life in similar systems.The enrichment of trace elements in sediments is intricately linked to biological activity and redox conditions given that some trace elements serve as bioessential components, while others exhibit redox-sensitive behavior. Given that carbonate minerals can adsorb 35 and incorporate trace elements during mineral precipitation, the distribution of these elements between the fluid and mineral phases provides valuable insights into biogeochemical processes and environmental conditions. This study aims to explore the patterns of trace elements within sedimentary carbonates of Mono Lake to unravel the associated processes. To achieve this, we have employed multivariate statistical methods to analyze an 𝜇XRF dataset (normalized to Ca) of trace elements in Mono Lake samples. Factor analysis, principal component analysis (PCA), and clustering techniques have been utilized to identify potential patterns among trace elements, which can infer specific redox conditions, the partitioning of bioessential elements, and/or the presence of detrital components.The analysis has revealed that some trace elements that cluster, such as Co, Ni, Cu, Zn, and As, may be associated to a biological component. Detrital provenance is likely represented by elements such as Ti, Fe, Al, Mg, and Rb. Some laminae are enriched in redox-sensitive and biologically relevant trace metals (such as Mo, V, Fe) that could be associated to organic enrichment or other minerals such as pyrite. Although this is a preliminar analysis, it is useful to focus further studies with more precise analytical techniques. Further research is crucial for refining and validating findings,providing a comprehensive understanding of microbialite formation, evolution, and diagenesis.Unraveling trace element patterns will enhances understanding of microbialite formation and their potential as indicators of ancient life forms.