The geology and palaeoecology of the newly discovered Cretaceous neosauropod hydrothermal nesting site in Sanagasta (Los Llanos Formation), La Rioja, northwest Argentina

► The Cretaceous Sanagasta nesting site shed lights on the reproductive behaviours of neosauropods. ► This research described the geology, petrology and geochemistry of the Sanagasta nesting site. ► We assessing the regional Cretaceous palaeoenvironment for nesting of Sanagasta neosauropods. ► It resolves geological issues on the sedimentary basins in the Sierras Pampeanas, Argentina. ► And offers answers to palaeobiological issues on Cretaceous neosauropod nesting and reproduction.