Rare Earth elements proxies of early diagenesis and oxygenation conditions in distal carbonate ramps: Vaca Muerta Formation unconventional reservoir subsurface study case

Abstract

Rare earth elements plus yttrium (REY) hosted in marine carbonates provide valuable constraints on seawater chemistry, redox conditions, and basin restriction. However, their application to mixed carbonate–siliciclastic successions remains challenging due to potential contamination by detrital phases, phosphates, and Fe–Mn oxides, particularly in organic-rich epicontinental basins. This study investigates the reliability of carbonate-hosted REY proxies in the Late Jurassic–Early Cretaceous Vaca Muerta Formation (Neuquén Basin, Argentina), deposited in a stratified deep-ramp system characterized by strong lateral paleoenvironmental gradients.