R. García Giménez

Application of chemical, physical and chemometric analytical techniques to the study of ancient ceramic oil lamps.

A chemical, mineralogical and morphological characterization of 54 fragments of oil lamps found in two Spanish archaeological sites (Cordoba and Herrera de Pisuerga (Palencia)) has been performed. Flame atomic absorption and emission spectrometry were used for the determination of Al(2)O(3), CaO, Fe(2)O(3), K(2)O, MgO, MnO, Na(2)O and TiO(2) as major constituents and Cu, Cr, Ni, Pb and Zn as minor and trace selected elements. Physical, mineralogical and morphological analyses were made by using dilatometry at constant heating rate for the thermal behaviour, X-ray diffraction spectrometry for the mineralogical composition and, in a group of selected samples, scanning electron microscopy and polarizing petrographic microscopy for the observation of thin layers and mineral identification. Separations of light and heavy minerals were carried out with bromoform and X-ray diffraction analysis was applied to both fractions. Multivariate statistical analysis was used to establish correlations between variables and to deduce factors which allow the gathering of oil lamp samples in groups as a function of their composition. The results of these analyses allow the comparison among pieces and the establishment of conclusions about several aspects of their manufacture, the origin of the raw materials and the provenance of the oil lamps (local or imported). They provide information supporting certain archaeological hypothesis. For example, some oil lamps found in Herrera de Pisuerga showed a clearly different physicochemical composition. They were probably brought from Italy by the Roman Legions together with their initial furniture household.

Red palaeosols sequence in a semiarid Mediterranean environment region

In this work we study one of the most palaeopedological sequence formed in Central Spain, which is located on the Pliocene–Pleistocene erosional surface in the Madrid Basin. We also analyse its relationship to erosive and sedimentary Pleistocene events in order to obtain new data for a correct interpretation of the origin and evolution of forms at the top of tabular lands in this site. The geomorphic features and the properties of a sequence of very red palaeosols that developed on this old surface can help us in the understanding of the palaeoclimatic evolution of Central Spain in a Mediterranean climate. They were examined to identify pedologic and climatic changes during the Quaternary. The soil sequence comprises intercalated palaeoargillic and palaeopetrocalcic horizons. The clay minerals are mainly illite, kaolinite, smectite and sepiolite. The alternation of argillic and calcic horizons, limestone debris (cryoclastic colluvions) and aeolian sands suggests succeeding periods of phytostability and phytoinstability (biostasis/rhexistasis). Argillation, rubification and calcium carbonate accumulation were repeated throughout the Pleistocene and it is hypothesised that climatic conditions during numerous stages of this period were not very different from the present conditions.

Characterization of loess in central Spain: a microstructural study

The purpose of this paper is to characterize the materials developed in the middle Tajo River valley, Central Spain. These sediments are loess, the characterization of which has not been reported in the international bibliography. The sediments are related to the next geological context and their characterization is indispensable to locate the said material in the adequate environment. A few different methods have been employed in this study, such as the pipette method (for determining the grain size) and separation of the light and heavy minerals of the sand fraction by using bromoform. The mineralogical composition was determined by XRD and textural study was accomplished by SEM/EDX. The loessic materials are silt-clay or sandy-silt that are quite unstable. The mineralogical composition shows quartz, feldspar, calcite and clay minerals. Some samples show gypsum; this mineral and calcite present dissolution and stability problems. The heavy minerals starting from the sand fraction are tourmaline, zircon, garnet, staurolite, sillimanite and biotite associations. The studies carried out with SEM show that the quartz grain surfaces present etch pits typical of the wind-blown origin.

An assay on simulation of the late Roman amphoric ceramic raw materials

A statistical study of the physico-chemical and mineralogical properties have been carried out on a select group of the late Roman amphora from the Museo Municipal of Ceuta, Spain, and on several clay seams potentially used in ancient times and located in the surroundings of Ceuta (on the African coast of the Straits of Gibraltar), has offered us the possibility of finding analogies between them. The analysis performed enabled us to link, as a first approach, the amphora with the clay materials used in their manufacture, by mainly using factors involving iron oxide content and the type of feldspar.