The preparation and conservation treatments of the human fossils from Lower Pleistocene unit TD6 (Gran Dolina site, Atapuerca) – The 2003–2009 record

Abstract The Lower Pleistocene unit TD6 at the Gran Dolina site (Sierra de Atapuerca, Burgos, Spain) has yielded human remains attributed to Homo antecessor . Many of these require some conservation treatment after recovery in order to be visible and consistent enough to be studied, safely handled, and preserved. In this paper we report the conservation tasks carried out on the human fossils collected during the second period of the excavation of unit TD6 (2003–2011). The main problems with these fossils are derived from the karst sediment filling in which they are found, essentially made up of clays, silt, and gravels that may be compacted and cemented and occasionally solidly adhered to the bones. In short, the treatments consisted of removing the matrix with manual and automatic tools, consolidating and rebuilding the fossils. The extent of treatments was adapted to the needs of the research and the entire process as well as the fossils before and after the intervention were strictly recorded. With this paper, we primarily aim to provide information that often remains unpublished and to share procedures that may be applied to fossils with similar problems. But in describing these treatments, we also aim to show that remedial conservation methodology is based equally on the mastery of the techniques and materials used for treatment and on the knowledge of fossils and the requirements of the studies conducted on them.