Podoconiosis, or non-filarial elephantiasis, was named and characterized by the late Ernest Price (Price 1988, 1990). He described the clinical features of swelling and deformity of the legs associated with enlargement of the draining lymph nodes. Histopathological examination of these nodes showed them to contain bi-refringent particles. He identified the epidemiological association between the local type of soil and the disease, and finally he confirmed this association by microanalysis of the particles in diseased tissue, showing them to be sub-micron aluminosilicate and silica, which are characteristics of the clay fractions of the local soil. It remains unclear what it is within the heterogeneous range of microparticles identified in tissue, and soil factors, that is responsible for the toxicity, and what are the host factors that determine certain individuals to be sensitive to them. Prevention of progression of the disease could be achieved by preventing further uptake of particles by using adequate footwear.
Single-grain detrital muscovite 40Ar/39Ar geochronology was performed on eight siliciclastic samples from the Mackenzie Mountains and Mackenzie Plain of the Northwest Territories. The rocks encompass two separate sample suites: the Neoproterozoic Mackenzie
Mountains Supergroup and the Devonian Imperial Formation. A majority of the muscovite sample ages (1200-875 Ma) from the Neoproterozoic strata suggest derivation from a Grenvillian-aged source to the east. Detrital ages from individual samples serve to refine the poorly constrained stratigraphic
ages for formations within the supergroup. Single-grain ages from the Imperial Formation range between 650-350 Ma, with a 425-400 Ma mode corresponding to the timing of collision between ancestral North America and a northern landmass throughout the Devonian. These new data allow re-evaluation of
current understanding of both the post-Grenvillian and pre-Ellesmerian source to sink pathways for siliciclastic strata of the Mackenzie River corridor.
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