Cyclicities in the sedimentary record have long been documented at di↵erent time and space scales. The longstanding debate is about the various origins that have been put forward to explain them : eustastic sea level changes, sediment supply variations, subsidence pulses or tectonic variations. In the deep water system of the lower-middle Eocene Ainsa basin, in the southern Pyrenees (Spain), as well as in its fluvial counterparts in the Tremp-Graus basin, stratigraphic cyclicity in the form of repetitive packages of sand and shale alternations of intermediate timescales (104 to 106 years) has long been recognized and has typically been imputed to eustatic changes, with a modulation by active tectonics. Most of the studies have so far focused either on the deep water system or on their fluvial counterparts without a detailed e↵ort at the correlation between both. Our objective is to evaluate the role of eustatic variations, that are well known to have taken place at these periods, in generating or modifying such cyclicities. This is particularly important in order to understand how sea-level fluctuations are tided to depositional environments over multi-millennial times- cales and how the deep-sea sedimentary record can be used to reconstruct the Earth's history of surface response to climate change. To address these issues, a mapping and multi-proxy approach was undertaken in the Tremp-Graus and Ainsa basins. We focus on the middle Eocene Castissent formation, a major fluvial excursion and its deep marine time-equivalent; the turbiditic sequence between the systems of Arro and Banasto ́n. Through a study of carbon and oxygen stable isotopes, geochemistry of major and trace elements and strontium dating performed on four increa- singly distal cross-sections, we attempt to trace environmental signals across the whole source-to-sink system. These analyses coupled with thorough physical mapping on the field allow us to discuss hypotheses of climatic and eustatic controls of cyclicity.