A GIS-Based Archaeoastronomical Approach to the Landscapes Built by the Mound Builders of Eastern Uruguay

This article presents an archaeoastronomical study of Indigenous mounds in the IndiaMuerta Wetlands region, Uruguay. These earthen structures, built and occupied from c. 3000 BC until the European conquest, played a crucial role in the landscape organisation of Indigenous populations. Data of various kinds, such as terrain elevation models, mound distribution and visibility models, were integrated and processed using Geographic Information Systems (GIS) and R (SkyscapeR package). The analyses reveal a high frequency of mound structures located at spots that create an artificial horizon as seen from other structures. This aspect may have played a key role in the landscape structuring and communication of these populations. Notably, the most prominent concentration of alignment measurements corresponds with the solar range, specifically the summer solstice and the southern major lunistice. A possible connection with some bright stars of the Milky Way, such as Antares, is also observed. The results of this approach highlight the importance of the knowledge of various astronomical phenomena in landscape construction by South American Indigenous peoples.