Isotope analyses to explore diet and mobility in a medieval Muslim population at Tauste (NE Spain).

The Islamic necropolis discovered in Tauste (Zaragoza, Spain) is the only evidence that a large Muslim community lived in the area between the 8th and 10th centuries. A multi-isotope approach has been used to investigate the mobility and diet of this medieval Muslim population living in a shifting frontier region. Thirty-one individuals were analyzed to determine δ15N, δ13C, δ18O and 87Sr/86Sr composition. A combination of strontium and oxygen isotope analysis indicated that most individuals were of local origin although three females and two males were non-local. The non-local males would be from a warmer zone whereas two of the females would be from a more mountainous geographical region and the third from a geologically-different area. The extremely high δ15N baseline at Tauste was due to bedrock composition (gypsum and salt). High individual δ15N values were related to the manuring effect and consumption of fish. Adult males were the most privileged members of society in the medieval Muslim world and, as isotope data reflected, consumed more animal proteins than females and young males.

Multispectroscopic methodology to study Libyan desert glass and its formation conditions.

Libyan desert glass (LDG) is a melt product whose origin is still a matter of controversy. With the purpose of adding new information about this enigma, the present paper analyzes the inner part of LDG specimens and compares them with the results of LDG surfaces. An integrated analytical methodology was used combining different techniques such as Raman spectroscopy, in point-by-point and imaging modes, scanning electron microscopy with X-ray microanalysis (SEM-EDS), energy-dispersive micro X-ray fluorescence spectrometry (µ-EDXRF), electron probe micro analyzer (EPMA), and optical cathodoluminescence (Optical-CL). According to our results, flow structures of the melt and the amorphous nature of the matrix could be discerned. Moreover, the observed displacement of Raman bands, such as in the cases of quartz and zircon, and the identification of certain compounds such as coesite (the most clarifying phase of high pressures), α-cristobalite, gypsum, anhydrite, corundum, rutile, amorphous calcite, aragonite, and calcite allowed us to know that LDGs could be subjected to shock pressures between 6 and more than 30 GPa, and temperatures between 300 and 1470 °C. The differences of temperature and pressure would be provoked by different cooling processes during the impact. Besides, in most cases the minerals corresponding to high pressure and temperatures were located in the inner part of the LDGs, with some exceptions that could be explained because they were trapped subsequently to the impact; there was more than one impact or heterogeneous cooling.Furthermore, nitrogen and oxygen gases were identified inside bubbles, which could have been introduced from the terrestrial atmosphere during the meteorite impact.These data helped us to clarify some clues about the origin of these enigmatic samples.

Combining Small-Vertebrate, Marine and Stable-Isotope Data to Reconstruct Past Environments.

Three very different records are combined here to reconstruct the evolution of environments in the Cantabrian Region during the Upper Pleistocene, covering ~35.000 years. Two of these records come from Antoliñako Koba (Bizkaia, Spain), an exceptional prehistoric deposit comprising 9 chrono-cultural units (Aurignacian to Epipaleolithic). The palaeoecological signal of small-vertebrate communities and red deer stable-isotope data (δ(13)C and δ(15)N) from this mainland site are contrasted to marine microfaunal evidence (planktonic and benthic foraminifers, ostracods and δ(18)O data) gathered at the southern Bay of Biscay. Many radiocarbon dates for the Antoliña's sequence, made it possible to compare the different proxies among them and with other well-known North-Atlantic records. Cooling and warming events regionally recorded, mostly coincide with the climatic evolution of the Upper Pleistocene in the north hemisphere.