Caracterización geomorfológica del yacimiento arqueológico de Ondaro (Nabarniz, Bizkaia)

Laburpena

Ondaro Cave (Nabarniz, Oka river basin, Biscay) is an abandoned cave passage with a series of incisions, ledges and erosional terraces located at different heights over the modern passage floor. A channel about a metre wide was eroded in the lower terrace or ledge (T1) and later filled with fluvio-torrential sediments deposited by a low-energy intermittent stream. Facies with clear evidence of human occupation formed on top of those sediments. The oldest of the levels has been dated to about 27,500 ± 120 BP (31,435-31,175 cal BP), which corresponds to the time of the Gravettian culture. Later, these levels were partially eroded by concentrated flows that washed out a series of hollows that became filled with sediment containing further evidence of human occupation, of an unknown age. Finally, the last part of the passage fell in, creating a collapse doline on the surface, which is the modern entrance to the cave. Again, the time of this event is unknown, but it might be dated in a time in the Holocene.