Archaeology: Cambodia, Land of Forgotten Prehistory

Editorial team
5 hours ago
4 min read

Along the Mekong River and in the caves of Battambang, Franco-Cambodian archaeologists are uncovering traces of human occupation dating back 600,000 years. This is the story of an investigation deep into the past.

The Mekong, the great river that flows through Cambodia, is not only a source of life for millions today. Beneath its clay banks and within the gravel of its riverbed lies a much older story: that of the first humans who lived in this region hundreds of thousands of years ago.

600,000 years: Estimated age of the oldest tools found along the Mekong

13 m: Depth of excavations in Laang Spean Cave — a Southeast Asian record

71,000 years: Age of the oldest tools attributed to Homo sapiens in the cave

2,191: Stone tools discovered and mapped in the cave

600,000-Year-Old Stone Tools

In the plains of eastern Cambodia, the banks of the Mekong reveal fascinating objects: crudely shaped stone tools, flakes crafted by human hands long before the country existed. These artifacts may date back 600,000 years—a time when Homo sapiens had not yet appeared.

What is a lithic artifact?

A lithic artifact is simply a stone object made or modified by humans. The term “lithic” comes from the Greek lithos, meaning “stone.” At that time, stone was the primary material used to make tools for cutting, scraping, and hunting.

The discovery of these sites dates back to 1963, when two French geologist-archaeologists, Edmond Saurin and Jean-Pierre Carbonnel, identified a first site near Kratié on an alluvial terrace of the river. For decades, their findings became a reference in prehistoric studies.

What is the Pleistocene?

The Pleistocene is a geological period spanning from about 2.6 million years ago to 11,700 years ago. It was the era of major ice ages and early humans. The “Middle Pleistocene” roughly covers the period between 800,000 and 120,000 years ago.

Doubt: The River as a Forger

In 2007, a Franco-Khmer team revisited the original site using modern tools. Their conclusion was troubling: some of these “worked stones” might not be human-made. The river itself, rolling pebbles over millions of years, could have produced shapes resembling tools—without human involvement.

A major issue: the original specimens studied in the 1960s have disappeared, making re-examination impossible. The debate remains open. However, in 2014, new analyses of recently collected objects provided stronger evidence supporting ancient human occupation.

Laang Spean: A Cave with 13 Meters of Memory

While debate continues along the Mekong, researchers have explored another extraordinary site: Laang Spean Cave in Battambang province. Its name means “bridge cave,” referring to natural arches formed after part of the ceiling collapsed.

How do limestone caves form?

Limestone caves form when slightly acidic rainwater gradually dissolves rock over millions of years. These caves often sheltered prehistoric humans, offering protection from weather and predators.

After 12 years of excavation across about 80 m², researchers reached bedrock nearly 13 meters deep—a record for Southeast Asia. Each meter represents thousands of years of human occupation.

~1500 BCE: Most recent layer — Neolithic presence (agriculture, pottery)
Several millennia: Intermediate layers — Hoabinhian hunter-gatherers
71,000 years: Deep layer — three stone tools attributed to Homo sapiens

How Are These Objects Dated? The OSL Method

Optically Stimulated Luminescence (OSL) dating measures the last time a grain of sand or mineral was exposed to light. Once buried, it accumulates a radioactive “charge.” In the lab, this charge is released as light to determine how long the object has been buried—like reading a natural clock in the sand.

2017: A Surprise 5 Meters Underground

The most striking discovery came in 2017, in a deep test pit named “Roland Mourer,” honoring a pioneering archaeologist. More than five meters below the surface, in a layer of sand and clay dated to about 71,000 years ago, researchers found three stone objects.

Only three—but enough to change everything.

These tools suggest that hunter-gatherers lived in the cave long before the Last Glacial Maximum, when ice covered much of the planet around 20,000 years ago.

“Each layer is a window into a different era. This long sequence is, to date, the longest cave sequence in Southeast Asia.” — Hubert Forestier, MNHN Paris, Director of the Franco-Cambodian Prehistoric Mission

The Hoabinhian Tradition: A Unique Stone Tool Technique

In the cave, archaeologists found over 2,000 tools belonging to the “Hoabinhian” tradition, named after a province in Vietnam where this industry was first identified.

What is Hoabinhian?

It refers to a distinctive way of making tools, typical of Southeast Asia’s late forest hunter-gatherers. Its main feature is shaping only one side of a pebble (unifacial flaking) by striking it with another stone. These tools are made almost exclusively from hornfels, a hard rock sourced from the nearby river.

The Paleo-Mekong Project: A New Generation

Research continues with a new generation of scientists. Justin Guibert (University of Toulouse) and Ngov Kosal, a Cambodian archaeologist trained in Paris, now lead the “Paleo-Mekong” project.

Their goal is to confirm the dating of Mekong sites using the latest techniques and to connect Cambodia to a broader regional picture.

Mekong terraces are not isolated cases. Similar sites exist in Thailand, Laos, and China. The tools closely resemble industries dated between 500,000 and 800,000 years in southern China. These links suggest a possible “prehistoric route”—a corridor through which hominins, possibly Homo erectus, migrated south along major rivers.

Homo erectus vs. Homo sapiens

Homo sapiens are modern humans, appearing around 300,000 years ago. Homo erectus is an older human species (about 2 million to 100,000 years ago), the first to leave Africa and spread into Asia. The two species may have coexisted in some regions.

More Than Science: A Shared Heritage

Beyond the data, the Franco-Cambodian Prehistoric Mission has deep human significance. At every stage—fieldwork, laboratory research, and publications—it trains Cambodian archaeologists so that this knowledge remains in Cambodia.

In the silent layers of the Mekong and the caves of Battambang, a nation is rediscovering its most ancient origins.