THE ORIGIN OF THE ACHEULEAN IN AFRICA

Homo ergaster appeared in Africa around 2 million years ago (Ma). It is often considered the first truly human species. It already had a modern body shape, a larger brain, could walk upright efficiently, and showed important advances in thinking and social behavior. It is thought that this species evolved in response to major environmental changes, especially the spread of drier, open savannahs in East Africa.

The Acheulean reflects these biological and environmental shifts. Named after the French site of Saint-Acheul, where it was first identified in the 19th century, Acheulean technology allowed humans to produce large flakes (over 10 cm long) from big stone cores. They could also shape large cutting tools, like handaxes, picks, cleavers and knives. These innovations marked a major step forward in human evolution.

These groups also began using and organizing the landscape in new ways. They had larger home ranges and more complex spatial patterns. Growing cognitive and social abilities are clear in the creation of standardized large cutting tools and their social transmission. The variety of tools also suggests more diverse diets and new ways of obtaining and processing food.

The earliest Acheulean evidence in Africa dates from about 1.9 to 1.7 Ma. Important early sites include Kokiselei 4 in Kenya, Melka Kunture and Konso in Ethiopia, and FLK West in Tanzania. Later sites, from 1.5 to 1.2 Ma, are found across the continent, including several sites in Olduvai Gorge and Peninj in Tanzania.

Our team has studied the Acheulean in Tanzania for years. On this website, you can explore our research at FLK West (Olduvai Gorge) and Peninj (Lake Natron), along with other projects, data, and updates about the African Acheulean. Welcome!

OLDUVAI GORGE

The legendary Olduvai Gorge is located in northern Tanzania, at the foot of the Ngorongoro Crater and south of the vast Serengeti plains. This great scar carved into the Rift Valley, with two branches, 50 km long and 100 m deep, began to form only about 200,000 years ago as a result of fluvial erosion. The sediments now exposed have made it possible to uncover the local geological history over the past 2 million years.

The archaeological richness of Olduvai is exceptional, both because of the large number of documented sites throughout the entire sequence and their remarkable state of preservation. For this reason, the site, studied since the early 20th century, has become a key reference for investigating the earliest stages of human history.

HISTORY OF RESEARCH IN FLK WEST

Following the pioneering work of Louis and Mary Leakey, Olduvai Gorge soon became one of the most important sites for understanding human evolution in Africa. Mary Leakey’s model for the origin of the Acheulean remained influential for decades.

Our team, in the framework of TOPPP (The Olduvai Paleoanthropology and Paleoecology Project) research conglomerate, began investigating the Acheulean in Olduvai in 2009. Later, remarkable discoveries in Kenya and Ethiopia pushed back the timeline for the emergence of the African Acheulean to around 1.8 Ma. Inspired by this new chronological framework, our team began a systematic archaeological survey in 2012, aimed at exploring local sediments of a similar age.

During that survey, FLK West was discovered by geologist David Uribelarrea, about 50 meters west of the well-known FLK site. Between 2013 and 2016, the first phase of research focused on a 17 m² area and produced results that have been widely published. Recognizing the scientific importance of FLK West, preparation work carried out since 2016 allowed the excavation area to be significantly expanded.

Since 2018, a second phase of research has been underway, focusing on an area of more than 100 m² and enabling a much more detailed exploration of the site.

GEOLOGY AND CHRNOLOGY

The sedimentary layers of the Olduvai Basin are complex and have been divided into seven geological units, providing an uninterrupted record of the last 2 Ma of local geological history. The lower units are the most studied and offer some of the richest scientific insights. At the base of the sequence, Bed I (2–1.8 Ma) was deposited in a mostly lake environment. From this period, many Oldowan sites are known, including FLK and DS, along with important fossil remains of Homo habilis, Homo ergaster, and Paranthropus boisei.

During the formation of Bed II (1.8–1.35 Ma), the landscape changed dramatically. The environment became drier, the lake shrank, and river systems expanded. This new fluvial regime led to the deposition of the Lower Augitic Sands (LAS), a fluvial unit made up of braided channels flowing toward the central paleo-lake and gradually merging into fewer streams downstream.

FLK West is located in one of these downstream channels near the lake margin. The channel is about 40 m wide, up to 1.2 m deep, and contains six stratigraphic layers, from L6 at the bottom to L1 at the top. The site is bracketed between two local volcanic tuffs dated by the Argon-Argon method to 1.69 Ma and 1.66 Ma.

RELEVANCE OF FLK WEST

FLK West brings together a remarkable set of features that make it one of the most important archaeological sites today for understanding the origins of Acheulean technology. Its main strengths include:

The site has been directly dated using radiometric methods and is precisely framed between well-defined chronological markers.
It is a multi-component site, with rich deposits of both stone tools (including a significant collection of large tools, big flakes, and large cores) and fossil bones across at least six archaeological layers.
Post-depositional processes have only moderately affected the integrity of the archaeological deposits.
FLK West is the oldest Acheulean site showing a clear functional link between animal remains and stone tools, and one of the earliest evidences of human processing of large herbivores.
A wide range of paleoecological, functional, and micro-archaeological studies has already been carried out here, highlighting the great potential of contextual approaches for understanding this record.

FINDINGS

FLK West featured a highly diverse ecological environment. Open savanna landscapes predominated, inhabited by animals such as wildebeest, gazelles, horses, wild pigs, antelopes, rhinoceroses, and elephants. Species adapted to aquatic and more wooded environments were also present, including crocodiles, hippos, waterbuck, and buffalo.

Carnivore activity at this site appears to have been limited. In contrast, human activity was much more intense. Cut marks and percussion impacts on the long bones of large animals indicate access to high-quality meat and fat resources.

Stone tools make up the majority of the material found at the site. Most of these were recovered from the lowest layers, L5 and L6. Across the sequence, the tools display several recurring features. Quartz was the preferred raw material, while basalt and chert were used much less often. Toolmakers mainly focused on producing small and medium-sized flakes, leaving behind cores, flakes, and retouched pieces. There is also clear evidence of percussion-related activities.

Tools associated with the Acheulean tradition (such as large cores, large flakes, and large cutting tools) are also present in the upper levels, although they are most abundant in the lowest layer (L6). These large cutting tools were most often shaped into pointed implements, although knives, cleavers, and handaxes have also been identified.

CURRENT RESEARCH

At FLK West, our research team is uncovering the story of early Acheulean humans through careful excavations and a wide range of studies. We explore how they lived, interacted with their environment, made tools, and how those tools were used.

STONE TOOLS AND TECHNOLOGY
We study how Acheulean toolmakers crafted their stone tools:

Identifying rock types and understanding how they were sourced and managed
Understanding the sequences of tool production
Analyzing patterns in tool shaping

SITE STUDIES
We investigate the traces left by humans, what they reveal about daily life, and how well the site has been preserved:

Mapping the spatial distribution of each archaeological layer
Interpreting the meaning of archaeological patches
Integrating all data using GIS to create a complete spatial picture

TOOL USE AND FUNCTION
We examine the question of how Acheulean tools were used:

Conducting experiments and analyzing wear patterns
Examining both microscopic and visible signs of use
Comparing experimental results with microscopic traces on archaeological tools
Detecting residues such as plant remains, starches, and other biomarkers on tools

HUMAN-ANIMAL INTERACTIONS
We study bones and animal remains to understand diet and competition:

Reconstructing early human hunting and scavenging strategies
Exploring how hominins coexisted with predators and other animals

LANDSCAPE AND ENVIRONMENT
We reconstruct ancient landscapes to understand how early humans adapted:

Studying geology, sediments, and soil structure
Analyzing fauna and microfauna
Using plant remains, such as pollen, charcoal, and phytoliths, to reconstruct the environment