Archaeologists have long contemplated an old mystery – where did early humans in the Hula Valley get flint to make the prehistoric tools known as handaxes?
Now a new study from Tel Aviv University (TAU) and Tel-Hai Academic College in the Upper Galilee has applied advanced methods of chemical analysis and artificial intelligence (AI) to identify the geochemical fingerprints of handaxes from the Hula Valley’s oldest prehistoric sites – Ma’ayan Baruch and Gesher Bnot Ya’acov.
Their findings prove that the raw material came from exposures of high-quality flint in the Dishon Plateau about 20 kilometers to the west and hundreds of meters above the Hula Valley.
The researchers said that their findings indicated that “these early humans had high social and cognitive abilities. They were familiar with their surroundings, knew the available resources and made great efforts to obtain the high-quality raw materials they needed. For this purpose, they planned and carried out long journeys, and transferred this essential knowledge to subsequent generations.”
The researchers added that early humans were highly capable. “They planned and implemented complex strategies and passed on essential information from one generation to the next.”
The study was led by Dr. Meir Finkel of TAU’s archaeology and ancient Near East cultures departments and Prof. Gonen Sharon of the master’s degree program in Galilee studies at Tel-Hai, in collaboration with TAU Prof. Erez Ben-Yosef, Dr. Oded Bar and Dr. Yoav Ben Dor of the Geological Survey of Israel and Ofir Tirosh of the Hebrew University of Jerusalem (HU).
They published their findings in the journal Geoarchaeology under the title “Evidence for sophisticated raw material procurement strategies during the Lower Paleolithic-Hula Valley case study.”
Ancient secrets in the Hula Valley
The Hula Valley, located along the Dead Sea Transform Rift, is well known for its many prehistoric sites, the oldest of which date back to 750,000 years YBP (years before present), said Finkel. The valley offered early humans rich sources of water, vegetation and game, right on the northward migration route from Africa – the Great African Rift Valley. “These early inhabitants left behind them many artifacts, including thousands of handaxes – flint stones chiseled to fit the human hand. One of the earliest and most universal tools produced by humans, the handaxe may have served as a multipurpose penknife for many different tasks from cutting game meat to digging for water and extracting roots. It was used in many different parts of the Old World, in Africa, Asia, and Europe, for about 1.5 million years.”
In the present study the researchers looked for the source of the raw material used to produce thousands of handaxes found at two prehistoric sites in the Hula Valley: Gesher Bnot Ya’acov, dated to 750,000 YBP and Ma’ayan Baruch, dated to 500,000 YBP, both of the Acheulian culture (relating to a Lower Paleolithic culture originating in Africa).
Sharon added that some 3,500 handaxes were found scattered on the ground at Ma’ayan Baruch, and several thousand more were discovered at Gesher Bnot Ya’acov. The average handaxe, a little over 10 centimeters long and weighing about 200 grams, was produced by reducing stones that are five times larger – at least one kilo of raw material. In other words, to make the 3,500 handaxes found at Ma’ayan Baruch alone, early humans needed 3.5 tons of flint.
But where did they obtain such a huge amount of flint? Many researchers have tried to answer this question, but the new study was the first to use innovative 21st-century technologies including advanced chemical analysis and an AI algorithm developed specifically for this purpose.
The researchers took samples from 20 handaxes – 10 from Gesher Benot Ya’acov and 10 from Ma’ayan Baruch, ground them into powder and dissolved the powder in acid in a clean lab. For each sample they measured the concentration of approximately 40 chemical elements, using an inductively coupled plasma mass spectrometer (ICP-MS) – a state-of-the-art device that accurately measures the concentration of dozens of elements, down to a resolution of one particle per billion.
To locate possible flint sources available to the Hula Valley’s prehistoric inhabitants, the researchers conducted a field survey covering flint exposures in the Safed mountains, Ramim ridge, Golan Heights and Dishon plateau, as well as cobbles from streams draining into the Hula Valley – the Jordan, Ayun, Dishon, Rosh Pina and Mahanayim. This methodical survey was combined with a comprehensive literature review led by Bar of the Geological Survey. Flint samples collected from all potential sources were then analyzed using ICP-MS technology to enable comparison with the handaxes.
The complex process, from collecting and preparing the samples to the chemical analysis, produced a very large amount of data for each sample, recalled Ben-Dor. To enable optimal matching between data from the archaeological artifacts and data from the flint exposures, we developed a dedicated algorithm based on several computational steps, alongside machine learning models. Thus, we were able to classify the archaeological artifacts according to the database derived from the geological samples.”
“Through the computational process, we discovered that all 20 archaeological artifacts were made of flint from a single source – the Dishon plateau’s flint exposures dating back to the Eocene geological epoch, about 20 km west of the Gesher Bnot Ya’acov and Ma’ayan Baruch sites,” said Finkel. At the Dishon plateau, we also found a prehistoric flint extraction and reduction complex, indicating that the place served as a flint source for hundreds of thousands of years.” The team also showed that cobbles from streams draining into the Hula Valley were too small to be used as raw material for handaxes, ruling out this possibility.
“Our findings clearly indicate that humans living in the Hula Valley hundreds of thousands of years ago, probably hominids of the homo erectus species, possessed high cognitive and social capabilities,” said Ben-Yosef.
“To procure suitable raw materials for producing their vital handaxes, they planned and carried out 20-kilometer hikes that included an ascent from 70 to 800 meters above sea level. Moreover, they passed on this important knowledge from one generation to the next, over many millennia. All these suggest a high level of sophistication and ability, which modern researchers do not usually attribute to prehistoric humans from such an early period.”