New York, Oct 24 (IANS): The highest altitude Ice Age human occupation anywhere in the world - nearly 4,500 metres above sea level (masl) - has now been documented in the Peruvian Andes.

Despite the cold temperature, high solar radiation and low oxygen conditions at the altitude, prehistoric people colonised the remote, treeless landscapes about 12,000 years ago during the terminal Pleistocene - within 2,000 years after humans arrived in South America.

The archaeologists led by University of Maine researchers discovered the settlement in a place called the Pucuncho Basin at an altitude of 4,355 metres.

They identified the remains of a related rock shelter nearby called Cuncaicha at an altitude of 4,480 metres. The rock shelter, with views of wetland and grassland habitats, features sooted ceilings and rock art, and was likely a base camp.

The Pucuncho archaeological site included 260 formal tools, such as projectile points, non-diagnostic bifaces and unifacial scrapers up to 12,800 years old.

"The Pucuncho Basin sites suggest that Pleistocene humans lived successfully at extremely high altitude, initiating organismal selection, developmental functional adaptations and lasting biogeographic expansion in the Andes," the researchers noted.

Cuncaicha rock shelter, featuring two alcoves at 4,480 masl, contains a "robust, well preserved and well dated occupation sequence" up to 12,400 years old, they added.

"Study of human adaptation to extreme environments is important in understanding our cultural and genetic capacity for survival," said lead researcher Kurt Rademaker from the University of Maine in the US.

Most of the lithic tools at Cuncaicha were made from locally available obsidian, andesite and jasper, and are indicative of hunting and butchering consistent with limited subsistence options on the plateau.

In addition to plant remains, bones at the site indicate hunting of vicuna and guanaco camelids and the taruca deer.

The findings appeared in the journal Science.