PROCESSUS D'EDIFICATION DE LA STRUCTURE DE POUSSÉE DU GLACIER THOMPSON, ÎLE AXEL HEIBERG, TERRITOIRES DU NORD-OUEST

Les photographies aériennes du complexe glaciaire formé par les glaciers White et Thompson (ǐle Axel Heiberg, Territoires du Nord-Ouest) acquises au cours des 30 dernières années indiquent que la structure de poussée qui se forme au front du glacier Thompson s'est élargie dans sa zone centrale ainsi que dans sa portion ouest, mais qu'elle a été comprimée dans sa portion est. Les observations sur le terrain confirment le caractère contemporain du développement asymétrique de la structure vers le sud-ouest, caractere qui a été propose dans une étude antérieure. Les observations effectuées en 1989 et en 1990 permettent ?affirmer que la structure ?empilement de blocs de graviers fluvioglaciaires qui forme ce que ?aucuns appellent la « moraine de poussée » du glacier Thompson ne résulte pas principalement de poussées horizontals de surface ni ?un dépǒt de strates de glace basale riche en materiel au front du glacier par écoulement compressif, mais plutǒt ?un ensemble de processus de nature glaciotectonique. On propose enfin un modèle de développement de la structure après avoir passé en revue les fondements théoriques de ?édification des structures de poussée en milieu gla-ciaire. The aerial photograph record depicting the proglacial area of the White and Thompson glaciers, Axel Heiberg Island, Northwest Territories, shows that the width of the Thompson Glacier push structure has increased in its western and central sectors, but has decreased in its easternmost sector over the last 30 years. The push structure, which is often referred to as a ‘push moraine’, is mainly composed of stacked up slabs of outwash material resulting from glaciotectonic activity. Recent observations were found to reinforce the asymmetric development trend of the structure toward the southwest that had been noted in an earlier study. Field observations in 1989 and 1990 also suggest that a set of processes related to glaciotectonism, rather than simple bulldozing or deposition of material-laden slabs of basal ice at the front, is mainly responsible for changes in the Thompson Glacier push structure. Theoretical aspects are discussed and a model relating to formative processes in the Thompson Glacier push structure is proposed.     

IS SCANNING ELECTRON MICROPROBE SUITABLE FOR COMPLETE ELEMENTAL ANALYSIS OF SOLDERS ON GOLD ARTIFACTS?

Summary. We comment on the inability of most scanning electron micro-probes equipped with energy dispersive solid state X-ray detectors to identify low amounts of cadmium in regions of solders on ancient artifacts. Traces of cadmium, even in the presence of high silver concentration determined with a nuclear microprobe, do not then contradict the results given by electron probes.     

A new Gaullist moment? European bandwagoning and international polarity

The transatlantic partnership needs to be reassessed. Since the end of the Cold War, Europe has chosen to bandwagon with the United States and to outsource its security to Washington. Bandwagoning has serious consequences when the use of force is at stake: it may lead to entrapment, where weaker allies may be involuntarily dragged into a conflict. It may also lead to abandonment, where the dominant ally may choose to discard their vital security concerns. With the evolution of the international system towards a multipolar configuration, this strategy of bandwagoning is becoming increasingly costly for Europe while the dominant power, the United States, is progressively confronted by other competitors at the systemic level. These classic dilemmas attached to an asymmetric partnership are exacerbated in a multipolar configuration. In particular, the abandonment scenario may become more and more frequent precisely because there is competition—and thus potential costs—at the international level: the United States may leave Europe alone, not by choice but by necessity. The current crisis in Ukraine illustrates this shift: while some American leaders were keen to escalate the conflict by arming Ukraine, the Obama administration's commitment to the defence of Europe has been minimal and it has largely delegated the management of the crisis to the Europeans themselves. Washington had other and more important priorities. Strategic autonomy is not an option for Europe; it has become a reality, a Gaullist moment where Europeans will have to learn to think and act strategically for themselves.     

LA–ICP–MS,SEM–EDS AND EPMA ANALYSIS OF EASTERN NORTH AMERICAN COPPER‐BASED ARTEFACTS: IMPACT OF CORROSION AND HETEROGENEITY ON THE RELIABILITY OF THE LA–ICP–MS COMPOSITIONAL RESULTS*

This study discusses the relevance of compositions obtained using laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) for the purpose of identifying the provenance of copper‐based artefacts found in Virginia at Native American sites dated from the 16th to the 18th centuries. Ten artefacts were investigated by scanning electron microscopy – energy dispersive spectrometry (SEM–EDS) to visualize the corrosion and characterize the heterogeneities in the metal and electron probe micro‐analysis (EPMA) to determine separately the compositions of the intact metal and of the corrosion product. It is shown that the corroded surfaces are highly depleted in zinc but that representative concentrations can be determined by sampling the deeper, uncorroded metal. In contrast, lead values are highly variable because of the heterogeneous distribution of this metal within the bulk copper. Despite these problems, brass is easily identifiable and American native copper and European smelted copper can be unambiguously distinguished with LA–ICP–MS on unprepared artefacts using As, Ag, Ni and Sb trace elements.     

L'EXODE URBAIN, ESSAIDE CLASSIFICATION DE LA POPULATION EXURBAINE DES CANTONS DE l'EST

A partir d'une enquěte auprès de 280 exurbains des Cantons de l'Est, on a trouvé que pour les Montréalais qui comptent pour le tiers des répondants, la distance ne semble pas étre un obstacle et qu'ils préfèrent des localités éloignées et isolées alors que les exurbains locaux sétablissent à proximité de leur ville d'origine. Cinq types d'exurbains ont été identifiés parmi deux courants principaux d'exurbanisation: le premier serait une phase tardive d'urbanisation, une continuation de l'étalement urbain; le deuxième en serait plutt un d'anti-urbanisation, relié au processus de changement dans les valeurs de notre société.
From a survey of 280 exurbanites in the Eastern Townships, Québec, it was found that Montrealers made up one-third of the sample. Distance from the city did not seem to be a hindrance to them, since they preferred isolated situations, whereas the local exurbanites were concentrated around their regional towns. Five types of exurbanites were identified among two main trends of exurbanization: the first is a late phase of urbanization, in which urban sprawl is continued; the second is part of a counter-urbanization process related to cultural change.