The find itself is not remarkable – two pieces of wood were joined together by hollowing out grooves so that they fit together. Unparalleled age: 476,000 years. This makes the discovery at Kalambo Falls in Zambia, East Africa, the oldest building in the world, built by a human species much older than our own.
-It’s so cool! It is incredibly well preserved, thanks to the fact that it may have been in water or mud for half a million years, says Larry Parham, professor of archeology at the University of Liverpool, about this discovery that caused a sensation around the world.
Several 100,000-year-old tools
He is leading the project Deep roots who has been exploring research sites in East Africa for nearly five years. Archaeologists from Great Britain, Belgium, Germany and Zambia have previously found, among other things, stone tools hundreds of thousands of years old.
-We expected to find stone tools, but not any wood or other perishable materials. Here we found a variety of tools that we have not seen in many other places. “But also beautifully preserved nuts and leaves,” says Larry Parham.
The place is located directly above Kalambo Falls, which is the second highest waterfall in Africa with a free fall of 230 metres. It is difficult to say what the wooden construction was part of. Archaeologists speculate that there was a waterside platform, an extension of sunken land, or a small jetty.
Here, early humans made tools and wooden objects and perhaps slaughtered game animals. Traces of possible hearths indicate that they cooked there as well. The fact that they put a lot of work into felling trees and building wooden structures shows that they stayed on the site for a long time. The fact that hunter-gatherers constantly roam is a fact with modification.
The finds were made on the edge of a steep river bank, which was 8-9 meters high. On the first day, archaeologists found a stone scraper lying on the ground. It was likely washed out of the clay bank recently – and dates back 390,000 years.
-We also saw a piece of wood sticking out, and we think it may have been an ax handle with a scraper as an edge. But the scraper can also be used without a handle, says Larry Parham.
Dated with scintillation
The wood itself has not been dated because the carbon-14 method cannot handle material older than about 50,000 years. Instead, luminescence dating is used. The method involves illuminating the mineral grain – in this case the wet clay in which the wood has been embedded – with ordinary visible light. Light interacts with radioactive elements and energy is released from them in the form of light, explains Geoff Dowler of Aberystwyth University in Wales, who conducted the dating.
-The longer the beans are packed under pressure and without light, the more light is released. You can see the grains glow as tiny dots of light in different colors. But this only works if they haven’t seen daylight since they were packed into sediment.
Therefore, the samples on the clay are collected in black plastic tubes that are pushed down into the clay and then closed at both ends. They are then opened in a darkroom in a laboratory, as when developing photographic film.
With international interest, archaeologists hope they can secure funding for a new project and return to digging further. But first, Larry Parham would like to see the site protected as a World Heritage Site – and discussions are underway with the Zambian government. The wooden find is now being preserved and will then be sent to the Livingstone Museum in Zambia.
-There’s more wood under what we found. Archaeologists who excavated here in the 1960s said they found wood two meters deep. Of the total 78 pieces of wood they used, one may have been treated in a similar way to the one we found.
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