Lines of Nasca
The Nasca Culture flourished in the valleys of southwest Peru from 100 B.C. to 600 A.D. Aside from their beautiful ceramics and textiles, the Nasca people constructed giant stone drawings and figurines that literally stretch for miles across the pampa (desert) and into the adjacent valleys. This odd collection of lines, trapezoids, rectangles, and triangles, called geoglyths, are also known popularly as the "Nasca lines" and have been the subject of numerous studies over the years since their discovery in 1927. However, the exact reason why these geoglyths were constructed remains a mystery. Recently, David Johnson, a Research Associate in the Department of Anthropology at the University, Don Proulx (Anthropology Department)and Stephen Mabee have assembled fairly convincing evidence suggesting that these geoglyths may be a map of the water supply distribution system for the ancients. There is a strong spatial correlation between the geology (faults which produce pathways and zones of water concentration in the subsurface), puquios (these are the aqueducts constructed by the ancients), archaeology (location of settlements), and the positioning of the lines of Nasca. We are testing this hypothesis further by applying standard geological and hydrogeological techniques, something which has never been done, to determine the source of the water to the valleys. We secured $27,000 in initial funding from three sources including $15,000 from the National Geographic Society.
The idea that the geoglyths represent a map of the water supply distribution system was tested initially during the summers of 1998 and 1999 at Cerro Aja in the Aja River valley just north of the city of Nasca, the Taruga Valley immediately south of Nasca, and Cerro Colorado located at the confluence of the Rios Nasca and Grande. These areas were selected because they are relatively small in area (a few 10's of square km), there are numerous existing wells in the area that can be studied, and the sites have been previously surveyed by David Johnson and Donald Proulx. The approach used in our investigation follows standard geological and hydrogeological investigative techniques. These include: 1) mapping the geology and characterizing the nature of bedrock faults; 2) geophysical surveying with seismic reflection, resistivity, ground penetrating radar and electromagnetic induction tools to map subsurface faults as they cross the valley; 3) surveying to measure water levels and map groundwater flow directions; and, 4) water quality sampling to help determine the source of subsurface waters.
Preliminary results suggest that our hypothesis may be correct; water-bearing faults in the bedrock do enter the valleys at Cerro Aja and Cerro Colorado and groundwater contours indicate that the groundwater flow direction moves from the bedrock along the valley sides towards the center of the valley. In addition, the geochemical signature of groundwater derived from side of the valleys is different from the water moving through the gravels beneath the rivers. Finally, these faults are marked by geoglyphs where they cross from the bedrock into the valleys. We are currently analyzing the remainder of the data collected during the summer of 1999 and hope to prepare a manuscript summarizing our results in early 2000.
The results of this work are potentially very significant because it may provide support for an exciting new explanation for the function of the Nasca lines. Furthermore, it is the first time that a coherent scientific approach founded in basic geological and hydrogeological principles has been applied to examine one of the great archaeological riddles of the world. If it can be shown that the geoglyths do indeed delineate the sources of water for the ancient cultures it will revolutionize the archaeological interpretations in this region. Finally, the indigenous populations of this region are poor and lack water. At a minimum, this work will provide additional understanding of the regions aquifers thereby supplementing their existing water resources and improving the quality of their lives.
A new proposal to continue our work in Peru during 2000 and 2001 has been submitted to NSF for funding. We plan on expanding our testing to include studying the relationship between water resources and the lines of Nasca in five valleys located in different regions of southwest Peru. The intent is to demonstrate that the correlation between the origin of groundwater and the location of ancient geoglyths is ubiquitous and is not a relationship that occurs in only a few isolated locations. We hope to expand the research and acquire funding to support additional students during the summers of 2000 and 2001.