Depositional age models in lacustrine systems from zircon and carbonate U?Pb geochronology

The Yacoraite Formation (Salta rift, Argentina) consists of Maastrichtian–Danian lacustrine carbonate and siliciclastic deposits with interbedded volcanic ash layers, organized in four third-order stratigraphic sequences. It offers the exceptional opportunity to jointly apply situ zircon U-Pb laser ablation-inductively coupled plasma mass spectrometry geochronology that resulted two distinct depositional age depth models. Ages youngest population from layers were linearly interpolated derive a model. A model was instead obtained dated phases including microbialites, ooids, oncoids calcitic dolomitic mineralogy as well early calcite cements. Mean ages defined different belonging same layer then interpolated. Sedimentation rates calculated both models between pairs samples used estimate sequence boundaries, duration agree biostratigraphic constraints exhibit excellent consistency. onset end sedimentation estimated at 68.2 ± 0.9 Ma 62.3 0.6 (duration ca 5.7 Ma) via 67.9 1.7 61.9 1.3 6.0 geochronology. Results this study show suitable newly implemented working strategy, dating diagenetic carbonates represent valuable chronostratigraphic tool for estimating rate poorly time-framed systems.