Evidence from burial sediments for prehistoric burial practice and ritual in Monte Claro chambered tombs: micromorphology, mineralogy and geochemistry

The burial matrix in archaeological graves is seldom subject to detailed examination for evidence of its potential interaction with the interred remains. Sediments adjacent to skeletal remains resting on a marl platform in a subterranean chambered burial dated to the third millennium BC were investigated using micromorphological, archaeobotanical, and chemical methods. Micromorphological features in the tombs, typical of CaCO3 depletion, appeared more abundant in positions close to the skeletal remains than in positions further away, suggesting that the carbonate dissolution was caused by acidification resulting from the body decay as well as from environmental factors. Organic signatures around the remains were dominated by background sedimentary organic matter of the marl, attesting to the exposed style of burial being unfavourable for the preservation of organic remains. Red concentrates present in a distinct region of the resting platform were distinguishable from similar coloured deposits formed by debris from the vault. They were identified as haematite (ochre) deposits, matching features observed in other prehistoric sites, including those of the same culture, and attesting to ritual associated with the treatment of the dead. Greyish fibrous contexts found on the burial resting platforms were identified as silicified sedge, probably remnants of the combustible parts of torches. The position and nature of the sedge-derived material suggests their use for illuminating the graves at depth and/or as a possible votive ritual. The detailed scientific examination of the burial matrix can reveal unique perspectives and add interpretative value to the archaeological investigation of graves.