With National Science Foundation support, Drs. John Kappelman and Lawrence Todd and a team of US and Ethiopian scientists and students will conduct three years of archaeological, paleontological, and geological research in northwestern Ethiopia. Through a series of controlled excavations, the project evaluates evidence that Middle Stone Age (MSA) humans living along the upper reaches of the Blue Nile River's tributaries on the lowland slope of Ethiopia's northwestern plateau were adapted to a riverine-based foraging lifestyle focused on the exploitation of highly predictable and abundant fish, mollusks, and mammals that were seasonally concentrated around waterholes during the dry season. Once local foods were depleted, longer distance foraging forays along the channel to new waterholes functioned as a dry season "pump" to siphon MSA populations out along the rivers. Not only would these "blue highways" have provided predictable foods and fresh water, but movements from one waterhole to another would have effected population movements northward along the Nile corridor. Investigating archaeological sites in this never before studied region will add to the growing body of knowledge about MSA behaviors. Because the research area is located in the Horn of Africa, a region hypothesized to be one of the places where modern humans possibly originated, and within the Nile corridor, a potential migratory route, these new data will further test and refine models of modern human origins and migration.
The intellectual merit of these focused excavations derives from their relevance to specific questions about human origins integrated within a larger study of the sedimentology, geochronology, and paleoenvironments. Taken together these data provide information of significance both to this research program, and to broader issues of African paleoecology. Absolute dating of the sedimentary sequences will provide a chronology for these sites so that the lithic assemblages and paleohabitat reconstructions can be compared with those from other MSA sites. The primary objective is to frame the paleoecological and paleoclimatic context of these MSA populations for a better understanding of their behavioral repertoire.
Broader impacts of the study will be realized on several fronts. First, the project brings together a team of scientists and students from the US and Ethiopia in a research partnership that integrates a diverse set of disciplines including archaeology, physical anthropology, paleontology, paleobotany, isotope geochemistry, sedimentology, geochronology, and community-based involvement in cultural heritage management and preservation. Second, the project emphasizes international student education to develop expertise in transdisciplinary studies. It will conduct a field school with a curriculum that includes training in GIS and GPS, faunal identification, use-wear, and mapping and excavation techniques, and emphasize student research. Third, the project includes educational outreach with the local and regional communities to develop stakeholder engagement in long term cultural and natural heritage management and preservation. And fourth, the project partners with governmental and private development groups working in the area in order to ensure that the cultural heritage is respected, managed, and preserved. The project will help train a new generation of Ethiopian heritage management specialists.
River in the lowlands of northwestern Ethiopia. The primary goal of the project was to reconstruct the ancient human MSA stone tool manufacturing techniques and foraging behaviors within the context of their paleoenvironments and determine the age of the occurrences of the MSA open air occupation campsites. This project represents the first time that MSA archaeological sites have been documented for this region of the Horn of Africa. The Blue Highways Project succeeded in locating numerous surface occurrences of lithic, faunal, and combined lithic and faunal associations that date to about 30-40 thousand years ago and include some even older sites. These associations offer new opportunities for investigating the behaviors of MSA populations at around the time of the migration of modern humans out of Africa. The Blue Highways Project demonstrated that MSA humans who lived in this region exploited a diverse set of both terrestrial and aquatic food resources that were available in these riverine habitats. Some of these foods included large mammals such as antelope and warthog, and a wide range of small animals including monkey, guinea fowl, ostrich, rabbit, snake, and rodent. Aquatic resources included crocodile, abundant fish, and mollusk. Reconstructions of the ancient environments using advanced geochemical techniques showed that the vegetation ranged from closed forest to open grassland. These data further provide support for the idea that the MSA populations generally occupied this region during the long dry season when the rivers, although greatly reduced in flow, still retained water in isolated waterholes that served to both trap the fish, thereby making them relatively easy to catch, and to attract the mammals to the only drinking water that was available on the landscape. MSA humans preferred to locate their open air campsites near the waterholes where food was relatively abundant. The MSA people who lived along the rivers generally made their stone tools from fine-grained silicate rock that is commonly found on the river gravel bars but sometimes used much more widely available basalt rock. Many of the small stone points that they made are within the size, shape, and weight range of ethnographically documented arrowheads. Microscopic use wear on these stone points shows that they suffered impact and cutting damage along their tips, and preserve evidence along their bases of hafting on shafts, which together strongly suggest that archery was practiced by these MSA populations. Our results from a controlled excavation of an open air campsite demonstrate that MSA humans engaged in complex behaviors which included maintaining separate areas for stone tool production and food processing. There is clear evidence for the control of fire, and burnt mammal and fish bone shows that the hearths were used for cooking. Student training was a central goal of the Blue Highways Project. Student from the US and Ethiopia participated in an annual field school that taught them archaeological field techniques. Students were responsible for excavating and mapping their own units, and learned how to record data and identify lithics and faunal remains. The Blue Highways Project trained 45 students from four US colleges and universities and two Ethiopian universities. These students will become tomorrow’s leaders in the field. A variety of genetic and paleontological data strongly suggest that the origin of modern humans dates to about 200,000 years ago in Africa, with the major migration of our species out of Africa occurring sometime between 70,000-45,000 years ago. The exit point from Africa is believed to have been in the Horn of Africa, either across the Red Sea to the Arabian Peninsula at the Bab el-Mandeb Strait, or north along coast of the Red Sea or the Nile River corridor. Whatever the case, it is likely that the riverine-based behavioral adaptations of the MSA modern humans who lived in the Horn played a critical role in their migration to the rest of the Old World. The archaeological sites discovered by the Blue Highways Project will play a central role in these ongoing scientific debates.
