Samples of one lichen species, Parmotrema crinitum, and one bromeliad species, Tillandsia usneoides, were collected in the state of Rio de Janeiro, Brazil, at four sites differently affected by anthropogenic pollution. The concentrations of aluminum, cadmium, copper, iron, lanthanum, lead, sulfur, titanium, zinc, and zirconium were determined by inductively coupled plasma-atomic emission spectroscopy. The environmental diagnosis was established by examining compositional changes via perturbation vectors, an underused family of methods designed to circumvent the problem of closure in any compositional dataset. The perturbation vectors between the reference site and the other three sites were similar for both species, although body concentration levels were different. At each site, perturbation vectors between lichens and bromeliads were approximately the same, whatever the local pollution level. It should thus be possible to combine these organisms, though physiologically different, for air quality surveys, after making all results comparable with appropriate correction. The use of perturbation vectors seems particularly suitable for assessing pollution level by biomonitoring, and for many frequently met situations in environmental geochemistry, where elemental ratios are more relevant than absolute concentrations.

Dans la région du Sud-Ouest du Niger, des bas fourneaux à usage unique ont été identifiés lors d’une prospection archéologique. À Saga Gorou, dans les environs de Niamey, un inventaire exhaustif de 4 504 bas fourneaux permet de proposer une analyse spatiale au sein d’un bassin versant, de 32 km², représentatif du paysage sahélien. Les sites métallurgiques de Bilfouda et de Garbel ont les plus fortes concentrations de bas fourneaux. Chacun d’eux a été cartographié avec précision à partir de photographies aériennes à basse altitude. Six dates radiocarbone, obtenues sur ces sites, sont comprises entre le ive et le ixe siècles. Une analyse spatiale à partir d’outils mathématiques (classification ascendante hiérarchique, k-moyennes, arbre couvrant de poids minimum) a mis en évidence des regroupements imbriqués de bas fourneaux. Quatre niveaux d’organisation, du local au plus global, ont été identifiés : la batterie, l’ensemble, le site, et le complexe. Chacun est défini par un nombre de bas fourneaux, une superficie, une durée de fonctionnement et un facteur déterminant le contrôle de la production. Au sein de la batterie, les bas fourneaux sont disposés en forme de fer à cheval ou en lignes plus ou moins rectilignes. Cette disposition est liée à une gestion maîtrisée de l’espace de travail et semble régie par des rituels socioculturels dépendant de la famille ethnique des métallurgistes.

In southwestern Niger, near Niamey, several thousand singleuse bloomery furnaces have been mapped and identified. The archaeological study of approximately 30 furnaces and their slag reveals the existence of four methods for iron smelting: three types of pit furnace and one slag-tapping type. The slag pit furnaces are clearly differentiated by the form and volume of their pits. All slag-tapping furnaces drain off slag through small openings. The slag is tapped either vertically or laterally. According to radiocarbon dates, the smelting activity developed in the 2nd century AD and intensified through to the 14th century. It continued to evolve until the middle of the 20th century. The low intensity of iron production for these furnaces indicates the products were intended mainly for the local market.

Photospheres, or 360 • photos, offer valuable opportunities for perceiving space, especially when viewed through head-mounted displays designed for virtual reality. Here, we propose to take advantage of this potential for archaeology and cultural heritage, and to extend it by augmenting the images with existing documentation, such as 2D maps or 3D models, resulting from research studies. Photospheres are generally produced in the form of distorted equirectangular projections, neither georeferenced nor oriented, so that any registration of external documentation is far from straightforward. The present paper seeks to fill this gap by providing simple practical solutions, based on rigid and non-rigid transformations. Immersive virtual environments augmented by research materials can be very useful to contextualize archaeological discoveries, and to test research hypotheses, especially when the team is back at the laboratory. Colleagues and the general public can also be transported to the site, almost physically, generating an authentic sense of presence, which greatly facilitates the contextualization of the archaeological information gathered. This is especially true with head-mounted displays, but the resulting images can also be inspected using applications designed for the web, or viewers for smartphones, tablets and computers.

The atmospheric dispersion atmospheric plume of the metropolitan region and neighborhoods of the city of Rio de Janeiro was investigated through elemental analyzes (Na, K, Al, Mn, Pb, Ni, Cr) and stable lead isotopes in two epiphytes; the lichen Parmotrema crinitum (Ach.) and the bromeliad Tillandsia usneoides (L.). All the elements had lower concentrations in epiphytes than in rocks of the local geological basement, with the exception of K, which was similar to rocks. This behavior was attributed to the nutritional essentiality and abundance of this element in the environment. The concentrations of Na, Pb and the 206 Pb/ 207 Pb and 208 Pb/ 206 Pb ratios indicated the presence of spatial gradients in the path (a) sea shore → continent, and (b) urban center → farmlands. These patterns were associated with the mesoscale atmospheric circulation regime, in which, during the arrival of cold fronts, air masses from the metropolitan region of Rio de Janeiro are transported towards the mountainous region of Teresópolis, which acts as a barrier to the dispersion of pollutants. The bromeliad Tillandsia usneoides and the lichen Parmotrema crinitum were linked to Na and Pb atmospheric levels, respectively.