ABSTRACT Deciphering sediment provenance is essential to understand depositional patterns and dynamics. This question is particularly important in archaeological contexts to constrain the sedimentological history of unearthed material—an information critically needed, for example, to estimate the age of the deposits—or to apprehend sediment movement and/or reworking in cave systems. Successfully used in several studies related to fluvial environments, mid‐infrared spectroscopy (MIRS) appeared in these contexts as a fast, cost‐efficient and effective method to assess sediment sources. We apply for the first time this approach to multi‐level cave systems in a karstic landscape along the Save and Seygouade valleys, in the Pyrenean foreland (Montmaurin, SW, France). Seven potential sedimentary sources for the sediments trapped in the karstic network were identified and characterised using 311 reference samples from 17 sampling sites. Discriminant analyses were performed to determine cave sample geochemical affinities with reference groups derived from these potential sources. The spectral signature of sediments artificially created by mixing two reference sources was also tested, to refine the interpretation of geochemical signatures when multiple provenances are involved. Sediments trapped in the studied caves mainly present geochemical affinities with ancient and/or modern alluvial deposits. Our results furthermore suggest that different depositional processes (e.g. slackwater flood deposits and vertical withdrawing) were at play, resulting, for a large proportion of the studied caves, in complex infills mixing several sedimentary sources. Beyond limitations related to the complexity of cave networks, this approach brought valuable information regarding sedimentation patterns, and could be further developed in the study of natural cave systems and underground archaeological sites.
Coraline et al. (Thu,) studied this question.