GIS Spatial-Temporal Modeling of Water Systems in Greater Toronto Area, Canada

Modeling landscape with high-resolution digital elevation model (DEM) in a geographic information system can provide essential morphological and structural information for modeling surface processes such as geomorphologic process and water systems. This paper introduces several DEM-based spatial analysis processes applied to characterize spatial distribution and their interactions of ground and surface water systems in the Greater Toronto Area (GTA), Canada. The stream networks and drainage basin systems were derived from the DEM with 30 m resolution and the regularities of the surface stream and drainage patterns were modeled from a statistical/multifractal point of view. Together with the elevation and slope of topography, other attributes defmed from modeling the stream system, and drainage networks were used to associate geological, hydrological and topographical features to water flow in river systems and the spatial locations of artesian aquifers in the study area. Stream flow data derived from daily flow measurements recorded at river gauging stations for multi-year period were decomposed into “drainage-area dependent“ and “drainage-area independent“ flow components by two-step “frequency“ and “spatial“ analysis processes. The latter component was further demonstrated to relate most likely to the ground water discharge. An independent analysis was conducted to model the distribution of aquifers with information derived from the records of water wells. The focus was given on quantification of the likelihood of ground water discharge to river and ponds through flowing wells, springs and seepages. It has been shown that the Oak Ridges Moraine (ORM) is a unique glacial deposit that serves as a recharge layer and that the aquifers in the ORM underlain by Hilton Tills and later deposits exposed near the steep slope zone of the ridges of ORM provide significant discharge to the surface water systems (river flow and ponds) through flowing wells, springs and seepages. Various statistics (cross- and auto-correlation coefficients, fractal R/S exponent) were used in conjunction with GIS to demonstrate the influence of land types, topography and geometry of drainage basins on short- and long-term persistence of river flows as well as responding time to precipitation events. The current study has provided not only insight in understanding the interaction of water systems in the GTA, but also a base for further establishment of an on-line GIS system for predicting spatial-temporal changes of river flow and groundwater level in the GTA.     

Pleistocene paleoecology of the Don and Scarborough Formations, Toronto, Canada, based on cladoceran microfossils at the Don Valley Brickyard

Cladoceran microfossil evidence has confirmed that a disjunction in environmental conditions existed during deposition of the Don and Scarborough Formations in Toronto, Ontario. Although mean annual temperatures were distinctly warmer during the Don interval than in the Scarborough, they were probably similar to the present-day regime. The cladoceran community was almost exclusively composed of littoral species throughout the sequence, suggesting that the deposition site was a shallow-water lentic habitat. Chydorid cladoceran species richness in the Don Formation averaged four times that in the Scarborough. Past community structure, water depth, and trophic state changes at the site were reconstructed from the proportions of littoral to planktic species, the proportions of sediment- to vegetation-preferring chydorids, and the species diversity and equitability.     

Chronologic and environmental implications of a new genus of fossil deer from late Wisconsin deposits at Toronto,Canada

A new cervine deer (Torontoceros hypogaeus), described from a partial cranium with portions of the main antler beams, has been recovered from deposits of early Lake Ontario age on the exposed bench of Glacial Lake Iroquois at Toronto, Ontario, Canada. The deer was about the size of a caribou, has heavy antlers that lie chiefly in a nearly horizontal plane, and its beams are bowed anteriorly. The tines are not flattened, the brow tines are asymmetrical, and no evidence of surface roughening or palmation of the beam is found. A ¹⁴C date of 11,315 ± 325 yr B.P. obtained on the antler allows the date at which Glacial Lake Iroquois drained to be revised to before 11,400 yr B.P. Spruce (Picea), pine (Pinus), and sedges (Cyperaceae) are major components of the associated pollen spectrum, which implies a typically interstadial or postglacial climate in which mixed forests grew in the Toronto area.     

氟铈硅磷灰石—产自加拿大Mont St.Hilaire的新矿物

新矿物氟铈硅磷灰石产自加拿大魁北京省的ＭｏｎｔＳｔ．Ｈｉｌａｉｒｅ地区，赋存于霞石正长岩、大理岩捕虏体，方钠石正长岩捕虏体和伟晶岩岩墙中。