10.1016/j.jas.2014.06.018 ; Several studies have attempted to identify diagnostic criteria for distinguishing between evidence of trampling and cut marks, two common modifications at archaeological sites. These studies have brought to light, with relative precision, the features that identify and differentiate the two types of modifications. However, few studies differentiate these modifications after they have been affected by other factors. Chemical alteration, related to lixiviated sediments, is documented in a relatively high number of archaeological sites. Following the criteria established by Domínguez-Rodrigo etal. (2009), the aim of this paper is to know if diagnostic criteria that would allow modifications resulting from trampling to be differentiated from cut mark modifications are preserved, after undergoing chemical alterations. The results have been applied to unidentified marks located on faunal skeletal remains from the La Mina site, at the Barranc de la Boella (Tarragona, Spain), the surfaces of which have been heavily modified by the lixiviation of the sediments. The data suggest that chemically altered marks lose the diagnostic criteria necessary for correct identification. The unidentified marks discovered on remains from la Boella could not be verified as cut or trampling marks and therefore cannot be considered in future zooarchaeological and taphonomical studies.