A high-resolution chronology and terrestrial ecosystem record of Early Pliocene Warmth onset in Europe from Camp dels Ninots, NE Iberia

Abstract The Early Pliocene Warmth (EPW) was one of the most recent intervals of sustained global temperatures above present, but its expression in European terrestrial environments remains poorly constrained. Here we establish a continental chronological and paleoenvironmental framework for the Camp dels Ninots maar-lake succession (NE Spain) using integrated ⁴⁰Ar/³⁹Ar geochronology, magnetostratigraphy, and multiproxy analyses. Incremental-heating ⁴⁰Ar/³⁹Ar dating of welded spatter deposits yields an eruption age of 4.70 ± 0.07 Ma, anchoring the onset of subsequent lacustrine sedimentation. Correlation of the polarity record with the Geomagnetic Polarity Time Scale, combined with sedimentation-rate modelling, dates the fossil-bearing interval to ~ 4.42 Ma and constrains the terrestrial onset of EPW conditions at ~ 4.45 Ma. Palynological assemblages indicate increased arboreal pollen and reduced aridity indicators, while mineralogical data support enhanced effective precipitation. Vertebrate faunas, including ectotherms and large mammals associated with closed habitats, further indicate ecosystem restructuring under warm-humid conditions. The preservation and chronological control of Camp dels Ninots provide a rare terrestrial archive for assessing continental paleoenvironmental responses during the EPW in Europe.