Zambian archaeologists have discovered a wooden structure dating back to the Early Stone Age or Pleistocene about 476,000 years ago. It represents the earliest known use of wood in construction by human ancestors. The discovery of Kalambo Falls has expanded scientists' understanding of the technical abilities that early humans must have had to shape tree trunks into large-scale composite structures. A study published Sept. 20 in the journal Nature details the findings. The structure itself may have predated the evolution of our own species (Homo sapiens) by 120,000 years.
Kalambo Falls is a 772-foot-tall waterfall located on the border of Zambia and Tanzania and is the second highest non-stop waterfall on the African continent. The timber structure discovered there in 2019 consists of two preserved interlocking logs, which are connected side by side by a deliberately cut notch. The logs above appear to have been deliberately shaped, with tool marks found on both logs, as well as a set of wooden tools.
This discovery is the earliest known evidence that humans intentionally molded two logs together to fit together. The authors believe that the logs may have been used to construct a raised platform, walkway, or to build the foundation of a dwelling on the periodically wet floodplains of the area. Previous studies have shown evidence that the use of wood at that time was limited to digging, spears, and fire. Another of the earliest apparently modified wooden objects was collected in South Africa in 1952 and dates back to the Middle Stone Age.
Study co-author Larry Barham, an archaeologist at the University of Liverpool, said in a statement: "This discovery has changed the way I think about our early ancestors. Forget the 'Stone Age' label and look at what these people were doing: they made new, big things out of wood. ”。They used their intelligence, imagination, and skills to create something they had never seen before, something that had never existed before. ”
In addition, the authors state that the discovery challenges the nomadic view of Stone Age humans. The Kalambo Falls will provide them with a constant source of water, and the forests around them will provide enough wood to help them build more permanent or semi-permanent buildings.
"They changed their surroundings to make life easier, even if it was just to build a platform by the river to sit on it and do their daily chores," Barham said. These people are more like us than we think. ”。
The team used new luminescence dating techniques to reveal the age of objects. It can estimate the time when the minerals in the sand around the wood were last exposed to sunlight. Analysis estimates that this artifact is nearly 500,000 years old.
Jeff Duller, a geographer and luminescence dating scientist at Aberystwyth University, a co-author of the study, said in a statement: "At this great age, dating a discovery is very challenging, and we used luminescence dating to do this. ”。These new dating methods have far-reaching implications – allowing us to go back even further in time and piece together what gives us a glimpse into human evolution.
The archaeological site of Kalambo Falls was first excavated in the 50s and 60s of the 20th century, long before dating techniques enabled archaeologists to understand the significance of these findings. Due to its archaeological significance, the area is currently on the tentative list of UNESCO World Heritage Sites.
This research is part of the Deep Human Roots project, an interdisciplinary, international team of researchers looking at how human technology developed during the Stone Age.
"Kalambo Falls is an extraordinary site and a major heritage site in Zambia," Barham said. The Deep Roots team is looking forward to discovering more exciting discoveries from the waterlogged sand. ”。