Morphogenetic processes on open-air rock art sites in tropical context: archaeo-geomorpho- logical analysis of the pre-Columbian rock art sites of Trois-Rivieres (Guadeloupe, French West Indies)

This work deals with the benefits of the archaeomorphological approach in rock art sites located in semi-tropical environment. Such approach was initially developed for studying rock art in caves and is applied here to two engraved pre-Colombian sites of Trois Rivieres (Guadeloupe): the Parc Archeologique des Roches Gravees and the Petit Carbet site. The aim was to identify the processes (gravitational, biological and hydrological) that shaped the current landscape, hence the spatial organization of the engraved rocks. Geomorphological mapping was conducted and supported by a high-resolution terrestrial LiDAR 3D mapping in order to identify landscape evolution processes pre-and post-rock art. Results show that before engraving, differential weathering of the volcanic rocks favored the genesis of monolithic formations. Those were later affected by mechanical processes (flaking and rock falls). Appart from the anthropic influence that affected some blocs (removal and displacement), the study highlights the influence of phytomechanical processes that were not considered until then. The integration of all those observations allows to reconstruct the shape of landscape at the time of the engravings. At another level, large planar spaces were identified on both sites without any rock art. They are the consequence of sediment infills linked with ancient flow paths. These results open new perspectives in terms of geophysical and archaeological investigations that could lead to a better understanding of the morphology of the site at the time of ornamentation, and potentially to the discovery, under the sediments, of ornamented ensembles, preserved from colonial and modern developments.