The wooden structure consists of two logs that attach to each other by means of a wide notch. The finding is the first evidence that wood may have been used for building structures as early as 476,000 years ago, according to a new study published in the journal Nature.
"Because the area is damp, the structure may have been used to walk on, or as a platform to keep things dry," said Larry Barham, professor of archaeology at the University of Liverpool.
Light reveals age
The wood had been preserved thanks to the moist and acidic environment of the river's sediments. The age of the logs was then determined using so-called luminescence dating.
"We have taken several samples from different parts of the wood, which means that we are very sure of the age," says Geoff Duller, professor of geography at Aberystwyth University in Wales, who helped date the find.
Homo erectus
There is no trace of what kind of man may have created the wooden structure because the acidic environment makes it difficult for skeletons to be preserved.
"It could be a descendant of Homo erectus, which is the species that we know has lived the longest of all human species. The oldest finds have been dated to 1.8 million years ago, says Larry Barham.
Stone Age engineers
On the other hand, the finding opens up new ideas about what the people of the time were capable of doing.
"Whoever could do this, it must have had a big brain, been able to plan and probably had a language to express itself with. A kind of engineering. We need to reevaluate our assumptions about hunter-gatherers from this era," says Larry Barham.
Play the video to see what the wooden structure looks like.