Unearthing earliest agriculture
"We found human teeth which can tell us something about the prehistoric diet. Huge amounts of fish and other bones were also found, which strengthen the hypothesis of aquatic adaptation. And at deep (old) layers we also found numerous grains in seemingly undisturbed layers with good charcoal samples for C14 dating. The oldest domesticated agriculture in Ethiopia may have been found!"
NAI researcher Terje Oestigaard is co-supervisor for PhD student Gedef Abawa Firew at the University of Bergen. Gedef’s project aims to find the earliest domesticated agriculture in Ethiopia. The earliest dates for the domestication of barley, wheat, sorghum and teff are all ca. 500 BC. This is very late compared to other places. The domestication in Ethiopia can be an indigenous development or it could have been introduced from other places, notably Sudan, Egypt or the Middle East. Only teff is ritualised, which means that the cereal is used for different ritual purposes. Compared to the cultivation and consumption of most other crops, teff exhibits some contrasting and unique qualities and processes. This indicates that the cultivation and exploitation of teff might have preceded the arrival of crops from outside and that it is the oldest domesticated cereal. Only archaeology can provide the answers.
Finding the right site for the project was a huge challenge, involving several steps. First, there is the survey. Gedef used one and a half month searching around the Lake Tana region asking farmers if they had seen any places with lithics and pottery. A local man told him that there was a cave with such finds at the peninsula; an hour’s walking distance from Gorgora, on the northern shores of Lake Tana.
The main excavation was conducted in late April and early May. Each layer was full of surprises and the find density was enormous. Findings from three grids (each one square meters) contained a lot of pottery remains and almost 4000 lithic artefacts, in addition to vast amounts of debris from tool production. Traditionally, the introduction of pottery has been linked to domesticated agriculture. Recent research, however, has shown that the origin of pottery is linked to aquatic adaptation along the great rivers and big lakes in this part of Africa.
In several layers tools such as blades and arrowheads were deposited vertically, which must have been done deliberately. Pottery remains and hippo bones were also found in a layer dated to ca. 4500 BC. The blades may have been used to cut hippos and then ritually deposited in the cave as sacred objects. Hippos have been seen as sacred animals in the Lake Tana region and there still exists a hippo-cult. In the past, young men could not marry before they had killed a hippo. The flesh of the hippo was used to procure fertility and hippo bones have been used for protection against malignant forces.
After the soil is sifted, it is carefully searched through for lithic tools and fragments, pottery, bones, botanical remains and charcoal. The charcoal is later taken for C14 dating. Depending upon the find density, this may take quite some time, but many of the most important finds are often found in the sifter. Gedef Abawa Firew with a big pottery fragment.
An archaeological excavation is a meticulous work. One by one layer is excavated and each grid is divided into four quadrants. In caves such as this the soil is often very compact and it is therefore difficult to follow the natural stratigraphy. Thus, one may excavate mechanical layers of five or ten centimetres. After a layer has been dug, it is measured and documented.
Finding all remains while digging is impossible and many of the remains may only be a few millimetres long. All the excavated soil is therefore sifted manually. The sifter has holes of two millimetres so the smallest finds are not lost.
Caves are often sacred places, used for ritual activities. The lithic material also points in this direction. According to local ethnography, lithic tools with several colours have particular magical qualities and powers. In several grids we found a huge variety of tools with diverse colours.
We found remains of two burials in the cave and there are probably several others. Caves are traditionally used for ancestral worship. Cracks in the rock are seen as entrances to the otherworld. In the cave there are solid traces of intensive firing next to the cracks. The ancestors also played an important part in rainmaking rituals, and if this was the case, after the rain arrived, it would have been impossible to use the cave.