Mineralogical changes in fossil bone from Cueva del Angel, Spain: archaeological implications and occurrence of whitlockite

The mineralogical changes undergone by fossil bones found in Cueva del Ángel, Lucena (Córdoba) were investigated in order to establish a first approximation to the site formation processes that occurred in the cave. For this purpose, 18 samples of fossil bones collected from the stratigraphic profile named J/K (the most complete of those studied on the site up to the present) were analysed. The results are interpreted as evidence of thermal events due to anthropic action on the basis of changes in colouration of the fossil bones, increased crystallinity of phosphatic phases and occurrence of rare authigenic phosphates (whitlockite). Diagenetic processes including phosphate authigenesis and presence of secondary precipitations of calcite and manganese oxides has been also observed. The analytical evidences further indicate that temperatures of about 650-700 °C were reached in Stratigraphic Units I and II, while less elevated temperatures were reached in Stratigraphic Unit III.