Caracterización química y mineralógica de los materiales grises de los cuerpos chinchorro modelados

This paper presents the chemical and mineralogical characterization of inorganic gray sediments used by the Chinchorro people to make their black mummies or reconstructed bodies. Thirteen samples taken from an inner layer of the black mummies (ca 4,000-2,800 BC) were studied to determine its mineralogical composition, plastic quality and whether it contained clay. The samples were analyzed at the Laboratorio de Investigaciones Medioambientales de Zonas Áridas, LIMZA (CIHDE-Universidad de Tarapacá), using energy dispersive X-ray fluorescence (EDXRF) and at the Laboratorio de Ciencias Geológicas de la Universidad del Norte, using X-ray diffraction and scanning electronic microscopy. In addition, experimental ceramic tests were undertaken at the Laboratorio de Conservación del Museo Arqueológico de la Universidad de Tarapacá, Arica. EDXRF result indicates the gray material was composed primarily of SiO₂ (68%), Al₂O₃ (13%), Fe₂O₃ (7%) and to a lesser extent, K₂O (4%), CaO (3%), Cl (2%), SO₃ (1%), and TiO₂ (1%). DRX analysis shows the mineralogical composition is quartz (30%), albite (26%), sanidine (15%) and muscovite (12%) among others. These results, along with the experimental ceramological testing and microscopy analyses, suggest that Chinchorro morticians used natural sediments that can be considered as medium to high quality clays to prepare the black mummies and did not add ground shells or grasses to the mixture.