Salas Lázaro, Paula Bartolomé Úcar, Miguel Giménez Portero, Reyes 2025 2025 The present study of the Cueva de Luzán (Los Fayos Zaragoza), located in the geological<br />context of the Ebro Basin and the Iberian Cordillera, aims to carry out a geomorphological<br />and geological characterisation of the cave, as well as to investigate its possible genesis<br />and evolution. The cave is located in the limestones of the Oncala Group (Upper<br />Cretaceous) and forms part of the karstic system that supplies the Ojo de San Juan spring<br />in Tarazona. The research includes methods such as mapping, stratigraphic and<br />hydrogeological analysis, characterisation of the internal morphologies and deposits and<br />the application of techniques such as 3D topography.<br />This work provides evidence of the speleogenesis of the Cueva de Luzán, through the<br />study of internal morphologies and cave deposits. From this analysis, two stages of<br />evolution have been established for the formation and evolution of the cave. The boxwork<br />structures, the tubes with ascending domes and the differential dissolution morphologies<br />such as the ‘Stone Bridge’ suggest that the cave was formed under phreatic conditions.<br />Subsequently, the cavity underwent a transition to vadose conditions as a result of a<br />lowering of the base level of the aquifer. It is at this time that the epigenic morphologies<br />were generated, such as the grooves found in the ‘Horizontal Tube’ and the internal<br />gravitational and alluvial deposits. The clastic deposits found at the entrance to the cave<br />provide information about the opening of the cavity to the exterior and about the alluvial<br />processes that almost completely clogged the entrance at some point in its evolution.<br />The transition from phreatic to vadose conditions could be related to the opening of the<br />Ebro Basin, an event that caused a transition to exorheic conditions and initiated an<br />incision of the drainage network due to a lowering of the general base level of the basin.<br />The final aim of this work is to offer a hypothesis that explains the origin and evolution<br />of the cavity,<br /><br />