The Mesolithic seen through a keyhole at S’Omu e S’Orku (SOMK) and the case of environmental hazards on the western coast of Sardinia, 9500–7800 cal BP

S’Omu e S’Orku (SOMK) is a collapsed rock shelter on the western coast of Sardinia, with a 9500–7800 cal BP geoarchaeological stratigraphic sequence encompassing the 9.3 and the 8.2 ka climatic events of the early Holocene. Sardinia is quite remote from the Italian coast and from mainland Europe, without firm evidence of human peopling before the onset of the Holocene. The animal species of the time were very few, all of them endemic, with Prolagus sardus , an ochotonid the size of a hare, by far dominant in the SOMK record. More local resources were novel for newly arrived people, like obsidian for producing lithic artefacts, but after the evidence from SOMK at first, they adapted and soon developed elaborated burial customs. The 9.3 event was characterised by wildfires burning the landscaped and by the ensuing debris flows sweeping the rock shelter. Then, when the environment stabilised again, a burial provides evidence of more human presence. The 8.2 event is marked by more wildfires and debris flows, and then at SOMK there is no more archaeological record. The sea-level is known was rising, eroding and invading stretches of the coasts. The human groups do not seem to have overcome all the compounded challenges of a quickly changing environment.