A study in Nature Communications reports that human groups in South Africa were making repeated trips to obtain toolmaking stone as early as about 220,000 years ago. Led by researchers associated with the University of Tübingen, the work centers on Jojosi, an open-air site where ancient people appear to have visited again and again for one main purpose, extracting hornfels for stone tools.
The finding gives archaeologists a rare look at early planning behavior in the Middle Pleistocene. At Jojosi, researchers found dense layers of stone fragments, hammerstones, tested blocks and other traces of production. The pattern suggests that people knew where to find a useful raw material, returned to that source across many generations and carried prepared pieces away for use elsewhere.
That matters because stone toolmaking begins before the first sharp edge is struck. Someone has to know which rock will break well, where to find it and how much effort it is worth. The Jojosi evidence shows that those decisions were already part of human behavior deep in the past.
Jojosi Reveals Targeted Stone Quarrying
Jojosi lies in the grasslands of eastern South Africa, about 140 kilometers from the Indian Ocean coast. Across this eroded landscape, natural exposures brought hornfels into view. The setting gave researchers a chance to study ancient activity at a place where raw material could be found directly in the ground.
According to the team, the site preserves an unusually clear record of targeted stone quarrying. The excavations revealed blocks that had been tested, flakes of many sizes, tiny chips from stoneworking and hammerstones used to strike the rock. These finds are the physical remains of people assessing and breaking stone at the source.
“At Jojosi, we found numerous traces of the quarrying of hornfels,” said Dr. Manuel Will of the University of Tübingen. That short description captures the core of the discovery. The evidence comes from the quarrying process itself, preserved as debris left behind during stone preparation.
Open-air sites can be difficult to interpret because wind, water and time often disturb ancient surfaces. Jojosi stands out because many hornfels flakes were found in stratified layers. These buried horizons allowed the researchers to examine activity in place, with the artifacts still linked to the sediments that held them.
Why Hornfels Was Chosen
Hornfels is a fine-grained metamorphic rock. In practical terms, it can be shaped into sharp tools when struck with skill. For Stone Age toolmakers, that kind of predictable breaking behavior was valuable. A poor stone could waste effort or fail during use.
The Jojosi team found that the people who visited the site focused overwhelmingly on hornfels. Other rocks were present in the broader landscape, including quartz and dolerite. The repeated choice of hornfels points to a clear awareness of raw material quality.
This selection was likely based on direct experience. Early toolmakers would have learned which cobbles fractured cleanly, which pieces produced large flakes and which materials held an edge. Over time, that knowledge could become part of how groups moved through the landscape.
At Jojosi, the preference for hornfels also helps explain why the site was worth visiting. The material was available in primary and secondary sources across the dongas, the eroded gullies in the area. These exposures created a dependable place to obtain stone suited for later tool production.
The result is a picture of early humans making practical decisions about geology. They were reading the landscape through the needs of toolmaking. A good stone source could become a known destination.
A Workshop With Almost No Finished Tools
One of the strongest clues at Jojosi comes from what the researchers found in abundance. The excavations produced large amounts of production waste. These pieces include flakes, small chips and other debris created as stone was broken and shaped.
The site yielded very few signs of other activities. Researchers found little evidence for settlement, food processing, or the kinds of finished tools that would usually mark a place where people lived for longer periods. That pattern supports the idea of a specialized workshop used for raw material preparation.
Dr. Will described the process in simple terms. “People worked cobbles on site here and knapped the material until they had achieved the desired shape from the rock.” The prepared stone could then be moved to another place, where it might be turned into tools or used in daily tasks.
This kind of behavior requires more than a quick stop. It involves knowing the source, selecting pieces, investing time in initial shaping and transporting useful blanks away from the quarry area. Each step adds weight to the interpretation that Jojosi was part of a wider movement and planning system.
The scarcity of finished objects also makes the site especially informative. Many archaeological sites mix several behaviors together. Jojosi preserves a narrower activity, which helps researchers isolate the early stages of stone tool production.
Repeated Visits Across 100,000 Years
Luminescence dating places the use of the Jojosi landscape from about 220,000 years ago to about 110,000 years ago. That range suggests repeated activity across roughly 100,000 years. The dates do not mean constant occupation. They point to recurring visits over a vast span of time.
This long duration is one of the most striking parts of the study. A raw material source can become important for one group in one generation. Jojosi appears to have remained meaningful across many generations, which implies some form of long-term landscape knowledge.
Knowledge of a stone source can move through a group in several ways. People can learn by traveling with older members. They can remember routes, landmarks and seasonal patterns. They can also pass on practical tests for judging stone quality.
The evidence at Jojosi fits with that kind of shared knowledge. Human groups repeatedly made short visits to sources of hornfels and left behind debris from the same broad activity. Over time, those visits built up dense archaeological layers.
For archaeologists, the duration matters because it connects toolmaking with memory. The repeated use of Jojosi suggests that ancient people maintained a mental map of useful places. That map included resources that could support future needs.
Stone Refits Show the Work Step by Step
The Jojosi study also used refitting, a painstaking method that can reveal how stone was worked. Researchers take broken pieces and try to reassemble them into their earlier form. When the pieces fit, they can show the sequence of strikes used during knapping.
Gunther Möller, a doctoral researcher at the University of Tübingen, successfully assembled 353 left-behind pieces into refits. These reconstructions allowed the team to look beyond scattered debris. They could follow parts of the toolmaking process in three dimensions.
“With these 3D puzzles, we were able to see precisely where and how material was chipped off and in what order,” Möller said. The quote reflects why refitting is so useful. It turns fragments into a record of decisions.
The refits showed that people removed material in ordered ways. They were shaping the stone toward desired forms, then taking the useful products away. This supports the interpretation that Jojosi was a place for preparing stone rather than using finished tools on site.
The density of finds adds to the picture. In some excavated deposits, the team reported very high concentrations of artifacts. Such dense layers point to repeated knapping events and intensive use of the same raw material source.
Planning Before Modern Technology
Planning in archaeology can be difficult to prove. Researchers must infer behavior from objects, sediments, dates and patterns across a site. Jojosi offers several lines of evidence at once, which makes the case unusually strong.
The first line is material choice. Ancient people selected hornfels again and again. The second is site function. The debris pattern points to extraction and early-stage preparation. The third is time. The activity appears to have continued across tens of thousands of years.
Together, these clues suggest advanced planning behavior among early humans in this region. People were preparing for later needs by obtaining stone in advance. They were also organizing activities across space, with one place used for raw material and other places likely used for tool finishing or tool use.
This does not require a modern village, written directions, or formal storage. It shows planning at the scale of mobile hunter-gatherer life. People moved through familiar landscapes and made choices that helped them solve future problems.
That kind of planning would have mattered in daily survival. A sharp edge could help process plants, butcher animals, shape wood, or perform other tasks. Reliable access to good stone would make those jobs easier and more predictable.
What Jojosi Changes About Early Humans
The Jojosi discovery adds weight to a broader shift in how scientists view early human behavior. Human groups in the Middle Pleistocene were flexible, skilled and able to organize tasks around future use. Their stone tools were part of a larger system of movement, memory and resource selection.
Professor Dr. Karla Pollmann, president of the University of Tübingen, emphasized the broader meaning of the site. “The finds from Jojosi reveal a rare, clear view of the early roots of humanity’s ability to plan.” That view comes from a place where stone fragments still preserve traces of ancient choices.
The study also highlights the value of open-air archaeology. Caves and rock shelters often preserve long records, but landscapes like Jojosi can reveal activities that happened away from living areas. A quarry site can show how people gathered the materials that made later tool use possible.
There are limits to what the evidence can show. The site records stone procurement and preparation, so it cannot reveal every part of life for the people who visited. It does show that early humans were repeatedly using a specific source for a specific purpose. That is a powerful signal of organization.
Jojosi’s importance comes from its clarity. Across layers of hornfels debris, refitted pieces, hammerstones and dated sediments, the site preserves a long record of practical intelligence. About 220,000 years ago, human groups in South Africa already knew where to go for good stone, how to prepare it and how to carry that value into the future.
