Non-invasive portable instrumentation to study Palaeolithic rock paintings: the case of La Peña Cave in San Roman de Candamo (Asturias, Spain)

► We have analysed the paintings considered World Heritage by UNESCO inside a cave. ► The analyses were overall conducted in-situ using non-invasive portable equipments. ► Chemometric techniques were also used to evaluate the whole analytical data. ► Differences in the used raw materials and pictorial techniques have been detected. ► Main deterioration processes of the cave were detected to favour its preservation.