Unearthing the Jojosi Quarry: Evidence of Early Human Resource Management

In the rolling grasslands of KwaZulu-Natal province in eastern South Africa, the Jojosi site has emerged as a pivotal discovery in understanding early human behavior. This open-air locality, characterized by eroded dongas or gullies, preserves stratified layers of stone-working debris dating back over 220,000 years. Researchers identified dense concentrations of artefacts in specific lenses, indicating repeated human visits specifically for raw material extraction. Unlike typical Paleolithic sites where stones might be casually picked up, Jojosi shows systematic procurement, challenging long-held assumptions about how Middle Stone Age (MSA) populations, likely early Homo sapiens, organized their tool-making supply chains.

The site's landscape features outcrops of hornfels, a durable metamorphic rock ideal for knapping into sharp edges. Early humans targeted both in-situ bedrock exposures and secondary deposits of angular blocks transported by ancient water flows. This deliberate choice highlights foresight in selecting high-quality material over more accessible local alternatives like dolerite or quartzite nearby.

South African Universities Lead Groundbreaking Paleoanthropological Research

Spearheading this study is an international team anchored by South African institutions, underscoring the nation's prominence in paleoanthropology. Manuel Will, affiliated with both the University of Tübingen's Early Prehistory and Quaternary Ecology group and the Palaeo-Research Institute at the University of Johannesburg (UJ), led the excavations. Contributions from the Evolutionary Studies Institute at the University of the Witwatersrand (Wits) included key geological and artefact analyses by researchers like Greg A. Botha and Aurore Val. These universities, renowned for their fossil-rich sites like Sterkfontein and Rising Star Cave, continue to train the next generation of archaeologists through programs in human evolution and lithic technology.

UJ's Palaeo-Research Institute, for instance, hosts interdisciplinary projects blending archaeology, genetics, and geosciences, fostering collaborations that yield high-impact publications. Wits, home to the Cradle of Humankind World Heritage Site, offers robust postgraduate degrees in paleoanthropology, attracting global talent. This Jojosi project exemplifies how South African higher education drives discoveries reshaping our species' timeline.

Precise Dating Methods Confirm Repeated Use Over Millennia

Establishing the chronology was crucial, achieved through optically stimulated luminescence (OSL) dating on 14 sediment samples. OSL measures the last time quartz or feldspar grains were exposed to sunlight, resetting their luminescence signal. Using post-infrared infrared stimulated luminescence (post-IR IRSL) on feldspar, the team obtained ages spanning approximately 220,000 to 110,000 years ago. Key layers include Jojosi 6 at 201–258 ka, Jojosi 5 at 136–187 ka, and Jojosi 1 at 106–139 ka.

• Bayesian modeling with OxCal integrated stratigraphic constraints for robust age-depth models.
• High-resolution gamma spectrometry determined dose rates from uranium, thorium, and potassium.
• Artefact lenses align precisely with dated horizons, ruling out later contamination.

This timeline places Jojosi within Marine Isotope Stages (MIS) 7/6 to 5e, contemporaneous with early Homo sapiens fossils at nearby Border Cave (~227 ka).

Irrefutable Signs of Deliberate Quarrying and Knapping Workshops

What sets Jojosi apart is the abundance of production waste without finished tools. Over 3,500 artefacts larger than 2 cm were documented, plus microdebris from sieving down to 1 mm. Cortical pieces (33–62% per layer) dominate, alongside core trimming flakes, platform rejuvenation elements, and angular shatter—hallmarks of initial reduction stages. Refitting experiments connected 353 pieces into 123 groups, some spanning full decortication sequences up to 49 cm apart but mostly <30 cm, confirming on-site knapping.

No evidence of domestic activities—no hearths, bones beyond one fragmented bovid at Jojosi 7, or diverse toolkits. Instead, multi-platform cores prepared for bladelet production and export of semi-finished blanks suggest task-specific visits: quarry raw blocks, reduce to portable sizes, transport elsewhere for final shaping.

As lead researcher Manuel Will notes, "At Jojosi, we found numerous traces of the quarrying of hornfels – a metamorphic shale – from outcrops that had been deliberately selected for their quality."

Photo by Hennie Stander on Unsplash

Hornfels Technology: Mastering Material for MSA Tools

Hornfels, formed by contact metamorphism, yields conchoidal fractures perfect for sharp edges. At Jojosi, the chaîne opératoire (reduction sequence) focused on opening blocks via hard-hammer percussion, producing débordant blades and flakes. Experimental knapping with replicas matched the debris profiles, validating interpretations.

This specialization mirrors MSA innovations like pressure flaking and hafting seen at sites like Sibhudu Cave, but Jojosi uniquely documents the upstream procurement phase. Blanks likely fueled toolkits for hunting, processing, and symbolic behaviors emblematic of behavioral modernity.

Challenging Paradigms: From Embedded to Specialized Procurement

Traditionally, models posited 'embedded procurement'—gathering stones opportunistically en route to other tasks. Jojosi refutes this: groups ignored abundant local quartzite (20 km away suitable alternatives), trekking specifically for superior hornfels. Millions of MSA hornfels artefacts downstream confirm export and landscape-wide use.The full study details this shift, suggesting planning horizons extended across generations, with site knowledge transmitted culturally.

This behavioral plasticity aligns with genetic evidence of Homo sapiens origins ~300 ka in Africa, manifesting in resource niche construction predating Upper Paleolithic 'revolutions' in Eurasia.

Global Comparisons and the African MSA Context

Globally, quarries like Taramsa 1 (Egypt, ~166 ka) show pits and complete reduction, differing from Jojosi's open-air blank factories. In South Africa, Wonderboom's Acheulean quartzite harvesting predates but includes tools on-site. Jojosi bridges Earlier and Later Stone Age, filling gaps in open-air MSA records dominated by caves.

In KwaZulu-Natal, sparse prior data (e.g., Umhlatuzana) now contextualized by Jojosi's longevity, linking to Border Cave's Howiesons Poort layers ~75 ka.

Implications for Human Evolution and Behavioral Modernity

Jojosi evidences early modern humans' cognitive toolkit: foresight, material expertise, social transmission. Over 110,000 years, climate shifts (MIS transitions) didn't deter visits, implying resilience and cultural continuity. This supports 'southern arc' models of sapiens dispersal from Africa.

For paleoanthropology, it emphasizes open-air sites' untapped potential, urging integrated geo-archaeological surveys.

Photo by Simon Hurry on Unsplash

South Africa's Higher Education Driving Global Discoveries

Institutions like UJ and Wits exemplify SA's research prowess. UJ's Palaeo-Research Institute integrates field schools training students in OSL, GIS, and refitting—skills vital for Jojosi. Wits' Evolutionary Studies Institute, with its fossil labs, complements through expertise in hominin contexts.

These programs attract international funding (e.g., Heidelberg Academy), boosting PhD output and publications. Amid challenges like funding cuts, such collaborations position SA universities as leaders in human origins research.Learn more about UJ's paleo initiatives.

Future Directions: Expanding the Jojosi Project

Ongoing work includes further OSL, pXRF geochemistry, and use-wear on transported blanks. UAV mapping aids landscape reconstruction, while student-led surveys probe upstream sources. Potential DNA from sediments or fauna could link to local sapiens populations.

This promises deeper insights into MSA economies, inspiring curricula in SA archaeology departments.