Calibrating the lithium-age relation and its dependence with rotation, activity and metallicity using open clusters and associations Acknowledgments: Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme focus ID 188.B- 3002. These data have been obtained from the GES Data Archive. This work has made use of data from the European Space Agency (ESA) mission Gaia. We acknowledge financial support from the Universidad Complutense de Madrid (UCM) and by the Spanish Ministerio de Ciencia, Innovación y Universidades, Ministerio de Economía y Competitividad, from project AYA2016-79425-C3-1-P and PID2019-109522GB-C5[4]/AEI/10.13039/501100011033. Preliminary results: dependence with rotation, activity and metallicity. Li-age relation Candidate members for each cluster are selected from the Gaia-ESO Survey (GES) (Gilmore et al. 2012) iDR6 data based on the following criteria: RVs, Gaia astrometry (proper motions and parallaxes), gravity indicators - Kiel (logg vs Teff) and 𝛾index diagrams, [Fe/H] metallicity, and the position in the EW(Li) vs Teff diagram. As an example we show here the case of IC 2602 (RV, PMs, CMD, EW(Li) vs Teff and 𝛾index) and NGC 6705 (Kiel diagram and [Fe/H] histogram): Selection criteria and cluster membership Abstract EW(Li) vs Teff: Plotting the lithium envelopes of IC 2602 (35 Myr), the Pleiades (78-125 Myr), and the Hyades (750 Myr) in a EW(Li) vs Teff figure, we can estimate age ranges and verify probable members (see Montes et al. 2001). Kinematic selection: We studied the RV distribution of each cluster by applying a 2-sigma clipping procedure and adopting a 2σ limit about the cluster mean yielded by the Gaussian fit to identify the most likely RV members. The Kiel diagram enables us to discard giant outliers (logg < 3.5) – some of them Li-rich giants (A(Li) > 1.5) – and other field contaminants. We used the PARSEC isochrones (Bressan et al. 2012), with Z = 0.019 and ages ranging from 1 Myr to 7 Gyr. For young clusters, we used the gravity indicator gamma (see γ index vs Teff diagram above) to discard giant contaminants before applying any kinematic and astrometric criteria,. Star Clusters: The Gaia Revolution MW Gaia WG 1/2 online workshop 5-7 October 2021 [Fe/H] histograms also help rule out stars with metallicities too far away from the mean for each cluster. M.L. Gutiérrez Albarrán1, D. Montes1 , H.M. Tabernero1,2, J.I. González Hernández3,4, A. Frasca5, A.C. Lanzafame5, R. Smiljanic6, A.J. Korn7, S. Randich8, G. Gilmore9, et al. & GES Survey Builders 1Departamento de Física de la Tierra y Astrofísica and IPARCOS-UCM, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040, Madrid, Spain; 2 CAB; 3 IAC; 4 Universidad de la Laguna, Tenerife; 5 INAF Catania; 6 Nicolaus Copernicus Astronomical Center; 7 Department of Physics and Astronomy, Uppsala University; 8 INAF Arcetri; 9 Institute of Astronomy, University of Cambridge In this work we use a series of open clusters and associations observed by the Gaia-ESO Survey (GES) to study the use of lithium abundances (Li I spectral line at 6708 Å) as an age indicator for pre- and main-sequence FGKM late-type stars. Previous studies of open clusters have shown that lithium depletion is not only strongly age dependent, but also shows a complex pattern with several other parameters, such as rotation, chromospheric activity and metallicity. Using the available data from both GES iDR6 and Gaia EDR3, we performed a thorough membership analysis and obtained lists of candidate members for 41 open clusters, ranging in age from 1-3 Myr to 5 Gyr. We then conducted a comparative study that allowed us to quantify the observable lithium dispersion in each cluster and study influence of rotation, activity and metallicity in the lithium dispersion of the selected candidates. All this allows us to calibrate a Li-age relation and create empirical lithium envelopes for several clusters in our sample.