PubMed1987
As specialisations of osteoarchaeometry become increasingly developed, so the need of new analytical techniques and tests of a skillful applicability becomes more necessary. The crystal-chemical and micromorphological evaluations of preserved bone discoveries implicate reliable methods as X-ray diffraction, electron microscopy, and spectroscopy with the skeletal materials and the soil environment in which bones are found. The reactivity of soils varies widely as geological and sedimentological conditions offer typical but different environments: gravels, chalk soil, clay, salt soils, sands, cave earths are examples of this wide variety, including atmospheric and biogenetic implications. The last mentioned features are strongly effective also in aride regions, with the well known fluctations of high parching and dewiness. However, despite the diversity in deposition and burial modes only few parameters govern the gradual decomposition of bone material: 1. pH value of the surrounding medium; 2. humidity of the surrounding medium, may be governed directly by autolysis; 3. transport of matter, related to grain size, pore volume, solubility behaviour; 4. physical pressure; 5. destruction by microorganisms; as well as the surrounding medium will be altered by the uptake and the transformation of the products of bone decomposition. The materials of investigation were skeletal fragments buried of ea. 10,000 a within the soft dune sediment of the western border mountains of Wadi el Araba (Arabia Petraea, Jordan). The discovered bones are, as a common feature of this locality Basta, strongly sintered--indication on the afore mentioned reactivity of the aride soil as well. Bone fragments were partially burnt at Sabra locality and discolored, and sintered also at these circumstances. The reactivity of the bone fragments is shown in terms of exchange reactions within the crystal structure of the bone mineral, apatite Ca5(PO4)3OH at the calcium sites, hydroxyl sites, and phosphate sites. These reaction schemes are interpreted in the details. This decomposition by substitution will often preserve the external appearance of buried bones. Fig. 1 and 2 show the extent of the actual ion exchange with the surrounding soil strata resp. transformed areas (sinter sheets); in the case of Basta material as a nearly total rearrangement of the anion lattice (phosphate, silicate vs. carbonate) as well as verified by Scanning-electron microscopy (Fig. 3, 4) and phase analyses by X-ray diffraction (Fig. 5-7): calcite and quartz are the principal components of the sinters, additional diffuse apatite lines appear in bone samples.(ABSTRACT TRUNCATED AT 400 WORDS)