En raison des circonstances exceptionnelles dues à la COVID-19, Érudit souhaite assurer à ses utilisateurs et partenaires que l'ensemble de ses services demeurent opérationnels. Cependant, afin de respecter les directives gouvernementales, l’équipe d’Érudit est désormais en mode télétravail, et certaines opérations pourraient en être ralenties. Merci de votre compréhension. Plus de détails
The original fascination of scholars with Quaternary vertebrates was more related to their sometimes astonishing size and characteristics than to their value in paleoenvironmental reconstruction. The dominant place occupied by Quaternary vertebrates in the paleontological literature owes much to the high visibility of larger species as well asto our own affinity with the Mammalia. Nevertheless, it is clear that vertebrate fossils have enormous potential in the reconstruction of ancient climates and environments. This po-tential extends to the detection of unusual environmental parameters, such as extentand severity of seasonal stresses and even such a specific factor as depth of winter snow. Although many of the larger Quaternary mammals became extinct, modern analogues exist for a large number of fossil forms, allowing inferences of temperature,moisture, substrate, vegetative cover or presence of particular food plant species. Further, the study of small vertebrates, whether mammals or other species, allows paleontologists to make similar inferences based on animals that are relatively tied to one place and cannot migrate as do large ungulates orbirds. Information obtained from these dis-parate sources can serve as a primary suiteof proxy environmental data, as a cross-check on other proxy sources, or as an element to be used in complex transfer functions employing input from multiple proxysources. As methods are refined, the potential for dating bones and teeth directly through radiocarbon, amino-acid racemization, electron spin resonance, uranium-series or other methods should ensure that vertebrate remains will also be of great value in establishing absolute time-sequences of local and regional environmental changes.
An ore deposit model is a conceptual and/orempirical standard, embodying both the descriptive features of the deposit type, and an explanation of these features in terms of geological processes. The descriptive features of models serve as criteria for exploration area selection ("area selection criteria").How they are used in this function dependson the scale of their spatial association withore, on our confidence that they are reliable indicators of ore, and on the extent to which they are prefer entially associated with economically better deposits. The geological, geochemical, and geophysical techniques used in exploration, and exploration strategy depend on area selection criteria. The relative importance of area selection criteria can be determined from their relative frequency of association with ore in a representative sample of the deposit population, resulting in an empirical model. A genetic model is derived by considering the genetic relationship of area selection criteria to ore. The weak links in model building are the lack of effort which goes into systematically assembling the data on the known population of deposits, and the weak scientific under pinnings of the genetic interpretation. Both of these factors influence exploration by leading to inappropriate assessments of the relative importance of area selection criteria. In addition,there are a number of human foibles which commonly lead to shortcomings in the development and use of models. The most significant of these is our tendency to rely toomuch on too simple models. We do this to avoid the discomfort of uncertainty and confusion which inevitably comes when we are called on to assess exploration situations.The history of exploration for massive base-metal sulphide deposits and gold deposits in the Canadian Shield provides a good illustration of the influence of models on area selection criteria, and thereby, on exploration strategy and techniques.
Robert Foulis, like his contemporary Abraham Gesner, was an extraordinary man whose interest in natural science and invention led him down a rocky path. Unfortunately, both Foulis and Gesner met with frustration as they attempted to explore and exploit the geological riches of New Brunswick. The invention of an illuminating fuel distillation process and the right to mineal bertite, a bitumen found at Albert Mines, New Brunswick, proved to be the bane of both men.