The Kalambo structure is a Lower Palaeolithic wooden structure, of which two pieces have been uncovered along with other wooden tools. Discovered at the site of Kalambo Falls, Zambia, it is currently the oldest known wooden structure, determined through luminescence dating to be at least 476,000 years old and predating Homo sapiens.
The structure consists of two interlocking wooden logs of large-fruited bushwillow (Combretum zeyheri), connected by a notch securing one perpendicular to the other. The smaller log, measuring 141.3 cm (55.6 in) in length, has tapered ends as well as a U-shaped notch and overlies the larger log, which passes through the notch. According to Duller, the structure probably would have been part of a wooden platform used as a walkway, to keep food or firewood dry, or perhaps as a base on which to build a dwelling. The discovery could indicate that the hominins who lived at Kalambo Falls may have had a settled lifestyle, which could challenge the prevailing view that Stone Age hominins had a nomadic lifestyle.
The notch in the upper log shows evidence of having been made through scraping and adzing, with fire use also hinted at by infrared spectroscopy. The underlying trunk shows evidence of striations with V-shaped cutmarks, both at its midpoint and along the narrowed end going through the notch, also indicative of possible scraping.
Using luminescence dating, the logs were dated to 476±23 kya. Carbon dating confirmed their non-intrusive nature, reporting an age higher than the maximum range of 50 kya.
Another wooden log, showing tapered ends and a similar notch, had previously been described in Site B of Kalambo Falls, also from the Acheulean, although not conclusively identified as part of a hominid-made structure at the time.
The wooden tools found along with the structure include a wedge and a digging stick. They have been found in several areas across the BLB site, and are younger than the structure itself, having been dated to between 390,000 and 324,000 years ago.