Structural geology and cave evolution at the gate of prehistory: The backbone of Grotta Romanelli, southern Italy

Grotta Romanelli (Romanelli Cave) stands as a key site of the European Paleolithic, preserving traces of human occupation since the middle Pleistocene. To date, little attention has been devoted to the carbonate bedrock that hosts the cavity, and to the role that tectonic structures played in its formation. To fill this gap, we conducted combined structural, petrophysical, and stratigraphic analyses, supported by the interpretation of a high- resolution 3-D virtual outcrop model of the cave and its surroundings. The results indicate that the cave was part of a system of Cretaceous extension- related structures affecting synkinematic carbonates. In particular, the cave opens within, and aligns with, an extensional fault– related anticline, which developed in the footwall of an embryonic extensional fault zone. The overall morphology of the cave and its progressive widening were strongly governed by exfoliation along preexisting discontinuities affecting synkinematic strata, namely, bedding planes and fault surfaces. Furthermore, the presence of porous, poorly lithified synkinematic Upper Cretaceous limestones, particularly at the thin entrance roof, raises critical stability concerns. The results of this integrated analysis, which provides the first geologically constrained 3-D model of the bedrock limestones of Grotta Romanelli, offer a robust basis for assessing the structural control, stability, and long- term evolution of the site. Results therefore enhance both scientific interpretation and management of limestone-hosted caves.