Saint-Maurice Abbey in Carnoët (Finistère) underwent an in-depth archaeological appraisal during 2018–2019, involving several non-destructive technologies: the geophysical survey revealed the presence of expected structures, drawn on ancient plans, but also the presence of structures unknown up until now. A group of buildings on the edge of the pond in particular raised several questions. A geochemical survey was carried out there in order to try to characterize these buildings and observe the potential complementarity between geophysical and geochemical surveys. The results of the chemical analysis do not highlight the same level of detail of the structures as electrical resistivity, but these analyses seem to be able to clarify the geophysical diagnosis by discriminating signals of structures from echoes linked to the geological substrate.