00/02425 A process and apparatus for treating solid fuel materials

Abstract

LITHOPROBE is Canada's national, collaborative, multidisciplinary geoscience project directed toward an enhanced understanding of how the North American continent has evolved. Research in its eight transects, which span the country and geological time, are spearheaded by seismic reflection studies. These, combined with other studies, provide new insight into the varied tectonic processes that have been active in forming the continent. The Archean Kapuskasing Structural Zone, a prominent feature which cuts obliquely across east-west Superior Province structures, has been imaged as a low-angle thrust sheet above a major décollement, along which 55–70 km of crustal shortening has occurred to bring mid-crustal rocks to the surface. The shortening was accomplished by brittle faulting and erosion at levels above 20 km and ductile shear and flow in the lower crust. The GLIMPCE transect in Lake Huron shows a spectacular series of east-dipping crustal-scale reflections that coincide with the Grenville Front Tectonic Zone. A two-stage model involves terrane collision with the cratonic margin in the Early Proterozoic followed by crustal-scale stacking and ramping associated with the Middle Proterozoic Grenvillian orogeny. In Lake Superior, GLIMPCE data reveal the structure of the Middle Proterozoic mid-continent rift that almost splits North America. The Lithoprobe East transect covering the Paleozoic Newfoundland Appalachians reveals three lower crustal. blocks, defined seismically on the basis of reflectivity characteristics imaged along the seismic profiles. Reflective upper crust can be related to geological structures at the surface; the thin-skinned tectonics implied have yet to be reconciled with the block tectonics of the lower crust. Results from the southern Canadian Cordillera show that the Mesozoic-Cenozoic east-west shortening in the eastern and central Cordillera occurred by compressional deformation forming crustal-scale antiforms that overrode a westward thinning cratonic North America; and in the western Cordillera by subduction processes that have tectonically eroded the lower lithosphere of accreted terranes and left underplated sediments and oceanic lithosphere. The reflection Moho has highly variable characteristics as imaged within transects and among different transects. Crustal and Moho reflectivity is caused by a wide range of features, including fault/shear zones, lithologie contacts, compositional layering, fluids in zones of high porosity, and anisotropy.