The southern Peruvian coastal desert around Palpa, southern Peru (14.5°S) is currently characterized by hyper-arid conditions. However, the presence of two species of molluscs (Scutalus, Pupoides) and desert-loess deposits indicates the past development of semi-desert and grassland ecosystems caused by a displacement of the eastern desert margin due to hydrological changes. Radiocarbon dating shows that the transition to a semi-arid climate in the southern Peruvian coastal desert took place during the Greenland interstadial 1, ∼ 13.5 cal ka BP. At the beginning of the Holocene, the mollusc fauna vanished due to increasing humidity and the development of grasslands. Dust particles were fixed by the grasses, as indicated by abundant Poaceae phytoliths, and desert loess was formed. The humid period we observe here is out of phase with the palaeoenvironmental records from the Titicaca region, which indicates dry conditions at that time. This paper offers a new idea for this contradiction: an orbitally driven meridional shift of the Bolivian high might have altered the moisture supply across the Andes.

Thirty years ago the use of isotope abundance ratios (IR) of bioelements in nutrition studies was a rather young discipline (Krueger and Sullivan 1984). Developed from hydrology, geochemistry, cosmo- and geochronometry isotope studies became a fertile tool also in other fields, and had an especially productive impact on archaeology, respectively, archaeometry (Koch et al. 1994; Buikstra et al. 2005).The advantage of isotopic parameters is that they are much more insensitive to often unknown influences compared to elemental concentrations or concentration ratios, where one has to deal with ambiguities which arise from differences in chemical properties of the elements. In contrast, IR of elements from various environments (including plants and bodies of animals and humans) are rather predictable or comprehensive after many studies although much remains to be done in this direction. The state of the art in isotope systematics has been presented in several monographs (Kendall and McDonnell 1998; Valley and Cole 2001; Johnson et al. 2004) and in journal articles (Schmidt 2003; Holzl et al. 2004, and many articles in Analytical Bioanalytical Chemistry 2004).The main objectives of isotope applications in archaeometry are to gain insights into ecosystems and food webs on which once-settling human groups and their animals subsisted, to find out about migrations and relations with trade partners from near and far, and to find hints to reasons why long-lasting socioeconomic evolutions and developments ultimately came to an end after a steep and rapid decline which had been interpreted empirically from archaeological and geomorphological evidence.

Micromorphological analysis of sediments from the Middle Stone Age site of Sibudu Cave, KwaZulu-Natal, South Africa, provides a high-resolution sequence and evidence of site formation processes of predominantly anthropogenic deposits. This methodology allows for a detailed interpretation of individual anthropogenic activities, including the construction of hearths and bedding and the maintenance of occupational surfaces through the sweep out of hearths and the repeated burning of bedding. This analysis also provides a context for evaluating other studies at the site relating to magnetic susceptibility, paleobotany, paleozoology, anthracology, and studies of ochre.

We present results from Fourier transform infrared spectroscopy (FTIR), transmitted polarising light and scanning electron microscopy (SEM-EDAX techniques), as well as phytolith analyses applied to sediments from Sibudu Cave. The Middle Stone Age sediments at Sibudu show minor degrees of diagenesis. This is demonstrated by the rarity of authigenic phosphate minerals, the occurrence of gypsum and calcite, and the absence of plant ash residues enriched in phytoliths and siliceous aggregates. Little loss of bone due to dissolution can be expected in such a sedimentary milieu. Therefore unearthed bones are likely to be in situ . The dry sediment conditions, which can be deduced from the stability of gypsum and calcite, make Sibudu a key site for faunal studies. Nevertheless, microscopic evidence of bone fragmentation through gypsum crystallization suggests that much of the mechanical bone destruction above layer GR is related to the growth of secondary gypsum. Furthermore, the comparatively dry sedimentary milieu at Sibudu is responsible for the good preservation of the fire-related structures. Hearths and ash dumps frequently show sedimentary compositions and phytolith contents similar to those of the sediments around them. This situation demonstrates that there was more fire use at Sibudu than the visible hearth remains and ash dumps indicate. Similar observations on visible hearth deposits and the sediments separating them have been reported at the cave sites Kebara, Amud, and Hayonim in Israel. We could not find clear correlations between sedimentary composition and colour. Sediments that look similar in the field may nevertheless exhibit different properties in respect to bone or ash preservation. To cite this article: Schiegl, S. & Conard, N. J. 2006. The Middle Stone Age sediments at Sibudu: results from FTIR spectroscopy and microscopic analyses. Southern African Humanities 18 (1): 149-72.

Sediments from Middle Stone Age hearths and burnt deposits in Sibudu Cave (KwaZulu-Natal, South Africa) were analysed for their mineral and phytolith contents. The mineral compositions were determined by FT-IR spectroscopy. The phytoliths were classified and counted by transmitted polarized light microscopy. Burning experiments using wood and grasses from species native to the cave's environment yielded the reference ashes. The visible hearths and ash dumps contain phytolith assemblages characteristic of wood fuel. A significant portion of the phytoliths of hearths and ash layers display morphologies related to intense heating. This finding is suggestive of long-burning wood fires and/or reuse of the same fireplace. The heat-altered phytoliths are useful in tracing fires, especially if hearth structures are not preserved and ash deposits have been diagenetically and heavily altered. The phytolith contents and mineralogical composition of the ash deposits and the surrounding sedimentary matrix are very similar. This feature suggests that the sedimentary matrix originally contained fireplaces and ash deposits, whose structures were destroyed shortly after deposition, presumably by trampling.(21) The intact circular hearths are most likely the product of intense fires. Similar results from hearths and their surrounding matrix have been reported from Middle Palaeolithic cave sites in Israel.

Hohle Fels Cave is one of several Upper Paleolithic sites on the eastern extension of the Swabian Alb in southwestern Germany. Several phases of excavations have been conducted since 1870. The archaeological inventories comprise a broad range of artifacts produced from stone, bone, teeth, ivory, and antler. The site has also yielded Paleolithic rock art, sculpture, and engravings. The Pleistocene inventories unearthed so far belong to the Magdalenian, Gravettian, and Aurignacian; Middle Paleolithic horizons may well be uncovered as excavations continue. The chronology of three main occupation phases has been established with numerous 14C measurements. The Magdalenian dates to about 13,000 yr B.P., and the richest Gravettian deposit contains a burnt bone‐layer extending over ca. 12 m2 that dates to about 29,000 yr B.P. The underlying Aurignacian horizons predate 30,000 yr B.P. The Gravettian burnt bone layer (archaeological layer IIcf) is a key horizon because of its distinct composition and color and its large horizontal extension. Layer IIcf has been examined using a combination of analytical techniques including micromorphological analysis of thin sections with polarizing light microscopy and scanning electron microscopy for fabric and identification of mineral and biogenic constituents. The bone mineral composition was analyzed by Fourier transform infrared spectroscopy (FTIR) and electron probe microanalytical techniques. These investigations in tandem with the field observations indicate intense burning of bones as fuel. The micromorphological and contextual archaeological data suggest that layer IIcf is a secondary dump rather than an in situ accumulation. This deposit and other Paleolithic burnt deposits in the Swabian Jura appear to reflect intense periods of winter occupation in these caves. © 2003 Wiley Periodicals, Inc.

Die Höhle Hohle Fels liegt auf der Schwäbischen Alb bei Schelklingen und beinhaltet eine stratigraphische Folge, die mindestens 36.000 Jahre zurück geht und Aurignacien-, Gravettien- und Magdalénien-Fundschichten beinhaltet. Die Sedimente vom Hohle Fels wurden mit mikromorphologischen Analysen in Kombination mit Elektronmikroprobe und FTIR-Analysen untersucht. Die Ergebnisse zeigen, dass die Sedimente aus dem inneren Bereich der Höhle stammen und das die feine Matrix in Zusammenhang mit der Nutzung der Höhle durch Bären eine starke Phosphatenanreicherung erlebt hat. Mikrostrukturen belegen kalte und feuchte klimatische Phasen, charakterisiert durch Kryoturbation und Eislinsen. Diese Merkmale sind in den Gravettien- und Magdalénien-Schichten stärker entwickelt und sprechen für kühle Bedingungen während dieser Perioden. Während des letzten Kältemaximums fehlen Hinweise für die Nutzung der Höhle durch Menschen und Höhlenbären. Diese Beobachtungen können als Grundlage dienen, um Hypothesen über das Paläoklima und über menschliches Verhalten im Paläolithikum, die anhand botanischer, faunistischer und archäologischer Daten entwickelt wurden, zu prüfen. Einige der Methoden dieser Untersuchungen wurden zum ersten Mal in den Höhlen der Schwäbischen Alb eingesetzt und lieferten viel versprechende Einblicke in die Archäologie und die naturhistorische Entwicklung der Region.

A study of the hearths and ash layers preserved in Hayonim and Kebara caves, Israel, showed that they are composed of one or several different minerals. These include the polymorph of CaCO3, calcite, a variety of phosphate minerals and a suite of siliceous minerals. The major component of the latter are siliceous aggregates that are present in wood. Detailed studies of the mineral associations in these fossil ash layers, as well as in fresh wood ash, using optical and scanning electron microscopy in the back scattered electron mode together with elemental analyses, showed that ash in these caves undergoes a series of diagenetic changes. The best preserved ash layers resemble fresh ash and are composed mainly of calcite with minor amounts of siliceous minerals. The calcite reacts with phosphate-rich solutions to form carbonated apatite and with time the latter dissolves and a variety of other phosphate-containing minerals form. With each diagenetic change, some of the more soluble minerals are lost and ultimately only the ash-derived siliceous minerals remain. In both caves there are local accumulations of such siliceous minerals that are metres thick. In fact ash-derived minerals in general are major components of the sediments in both Kebara and Hayonim caves. Their diagenesis involves a hugh reduction in volume, which in turn may have important effects on the geological structures and stratigraphy of the sediments. The changing mineralogy of the sediments due to diagenesis complicates the use of present-day estimates of radiation content of the sediments for correcting age estimates by thermoluminescence and electron spin resonance. Finally, the presence of the relatively stable ash-derived siliceous minerals in a sedimentary layer in other caves, could be a useful means of identifying the presence of ash in other archaeological sites where macroscopic hearth features are absent.

The thermoluminescence dating of burnt flints has become a major tool in the elaboration of the chronology of human settlements of the last half a million years. The reliability of an age estimate depends to a great extent on the accuracy with which the internal and external radiation dose rates prevailing during the duration of burial can be determined. While determining the internal dose rate is relatively straightforward, the same cannot be said of the external, particularly if the sediment surrounding the flints is mineralogically heterogeneous or has undergone diagenetic changes during prolonged burial. In this article we show some examples of the problems confronted when one attempts to determine the external dose rates experienced by flints buried in a relatively heterogeneous environment of sediments, such as those sampled at the Middle Paleolithic occupation levels at Hayonim (Israel) which show evidence of past mineralogical evolution. The impact of changes produced by leaching and chemical reactions between the components of hearth ashes on the radioisotopic composition of the sediment and consequently the environmental dose sates were examined by subjecting several distinct sediment layers to thorough mineralogical, radiochemical, and dosimetric analyses. The problems of external dose-rate determinations in mineralogically heterogeneous sediments are examined, particularly in those consisting of variable amounts of siliceous aggregates, apatite, and other phosphorus-rich minerals produced by diagenetic reactions with bone residues.

The mineral assemblages in prehistoric sites can provide essential information on several important topics in archaeology. One of the key analytical tools used is Fourier-transform infrared spectrometry, which is operated both on-site during the excavation and in the laboratory. Three topics are reviewed here based on studies of Hayonim and Kebara caves in Israel. (1) Reaction rims form on calcitic and dolomitic rocks buried in the sediments. They are normally the result of interaction of the rock minerals with phosphate-rich groundwater. The mineralogical nature of these reaction rims can be indicative of prevailing chemical conditions in the sediments, which in turn provide information on whether or not bones are preserved at the site, or are preserved at specific locales within the site. Thus, a survey of reaction rims can be helpful in determining the potential of a future excavation site, or areas within a site, and for optimizing excavation strategies during an ongoing project. (2) The preservational states of the bones themselves, together with information on the mineralogical nature of some of the more labile sediment components, can be used for ascertaining whether or not the bone distribution patterns as excavated represent the original burial locations, or have been affected by secondary dissolution of bones in some areas and not others. (3) The ashes from wood fires are a major component of the sediments in both caves studied. Understanding and monitoring the complex series of diagenetic changes that ashes undergo in these environments can provide invaluable information, not only on the manner in which fire was used by the cave occupants, but also on a series of important processes that affect the depositional history of the site itself. The study of mineral assemblages in prehistoric cave sites, as illustrated here with 3 examples, and possibly in open-air sites as well, has the potential for contributing significantly to a better understanding of many archaeological problems.

Polished cross sections through more than 1000 pigment samples from ancient Egyptian monuments (5th Dynasty to Roman Times) were investigated in reflected light, with SEM, and with electron microprobe techniques (EMPA). These combined analytical techniques allow many insights into the painting layers and down to the substrate. Textural relations of both the primary paintings and of the deterioration products can then be delineated. They also discern the stages of the various deterioration processes and the degree of damage of the painting layers. The textural patterns of six deterioration processes not known before are discussed in detail and are documented in BSE-micrographs. Five of these processes commence in synthetic Cu-pigments (Egyptian Blue, glass pigment, and Green Frit) and Fe-bearing glass pigments. The 6th process leads to the formation of complex phosphates and is mainly exogenous. It causes severe damage to natural and synthetic pigment layers. These processes result in destruction of the primary pigments and coloured decorations. Consequences as to the colour symbolism and future treatment of befallen paintings are discussed.