CHEMICAL AND MICROSCOPIC ANALYSIS ON SEDIMENTS AND HUMAN REMAINS OF THE JUNCAL LAGOON (VALLE DEL RIO NEGRO, NORPATAGONIA)

We present a multi-focus study based on human burials from Laguna del Juncal, deposited in a plaster wrap in the collections of two regional Museums of the Rio Negro Upper Valley since the 1970s. The remains present the characteristic dark coloration that has been frequently mentioned throughout the history of the archaeology of the Negro river, Argentinian Patagonia. The aim of this work is to study the coloration of the remains (natural vs. anthropic) and evaluate their chronology. To achieve this, a bioarchaeological, chronological and taphonomic characterization of the individuals and their sedimentary matrices is presented, using chemical and microscopic analyzes. Two individuals were excavated, an adult and a subadult, both with little associated cultural material, that were dated 720 +/- 24 and 754 +/- 24 years BP respectively. The preservation of the adult is fair to good, while the subadult presents worse preservation. By means of chemical microanalysis (SEM), high content of Mn and Fe was recorded in the sediments, as well as in the bone material, which would explain its dark coloration. The results are discussed within the framework of current knowledge of the burials of Northeast Patagonia.