Geolocation and Spatial Analysis of Underground Fired Earth Structures (UFES) on the Southern Coast of Laguna Mar Chiquita, Cordoba, Argentina

Abstract

Underground fired earth structures (UFES) are features excavated directly into the substrate, with ovoid, hemispherical, pyriform or bell-shaped forms, open at the top and varying in size and depth. They have rubified walls with diverse textures and lack a neck. Inside, they often contain layers of fine sediments over a base of charcoal and ashes. Although they are recurrently found at archaeological sites in central Argentina, their function remains uncertain, and the exact time of their initial construction and abandonment has not been determined. This pioneering study on the southern coast of Laguna Mar Chiquita, in the northeast of the Córdoba Province, aims to identify and map UFESs across five archaeological sites, focussing on their distribution, diameter and shape to detect possible patterns. The research included systematic surveying through the implementation of transects parallel to the coastline, using tools such as digital cartography, Garmin GPS, the Geo Tracker app for waypoint and transect track recording, a digital camera, compass, measuring tape and a GNSS (differential GPS) positioning system to obtain precise geolocations. The results identified 260 UFES, randomly dispersed within the sites but concentrated in a specific section of the beach. The UFESs were located between the coastline and the forest/shrub area, below an ellipsoidal height of 95 m, on a consolidated loess-like sedimentary substrate. Medium-sized UFESs, with diameters between 30 and 70 cm predominated accounting for 84% of the total. The selection of these locations suggests practices related to the use of saltwater, in a space conducive to social gatherings and communal activities. This study offers a comprehensive view of the presence and distribution of UFESs in the landscape and provides a solid foundation for future archaeological investigations in the area, thanks to the use of advanced technology and methods that improve geolocation accuracy.