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ECOLOGY See Also: Ecology of the Oak Ridges Moraine The Ecologically Diverse moraine is the source for many Headwaters Streams flowing south into rivers that drain into Lake Ontario and north into rivers that drain into Lake Scugog and Lake Simcoe . Varied landforms on the moraine, such as Woodland s, Wetland s, Watercourses , Kettle Lakes and Bog s, have provided an environment suitable for significant Flora and Fauna communities to develop and thrive. The moraine contains one of the last large contiguous forested spans in southern Ontario. is a threatened species in Canada. Happy Valley Forests is one of the few remaining Canadian habitats for this species.]] Some of the wide variety of plant and animal species found in the moraine are ''species at risk'' in Canada and Ontario, including the West Virginia White Butterfly , Jefferson Salamander , Red-shouldered Hawk , and American Ginseng . Unique ecosystems in the moraine include wetlands similar to those of boreal forests in Northern Ontario, and remnants of Tallgrass Prairie and oak-pine Savanna that are globally threatened ecosystems. A typical portion of the moraine may be found in the Happy Valley Forests , in York Region, north of Toronto . PHYSIOGRAPHY The "Oak Ridges Moraine" is a large ridge composed of four elevated wedges. It is bounded to the west by the Niagara escarpment, a Cuesta which was critical to the formation of the moraine, and to the east by the Trent River and Rice Lake. The four wedges (''Albion'', ''Uxbridge'', ''Pontypool'' and ''Rice Lake'' from west to east) formed in stages, though some synchronous formation also occurred at an early period of formation. The moraine peaks at the Uxbridge wedge, generally rising from east to west, a result of the moraine's west-to-east formation. That is, the western portion of the moraine received earlier and more frequent sedimentary deposition than the eastern portion, as the ice lobes which controlled the moraine's eastern formation slowly retreated. The Rice Lake wedge is separated from the other wedges where the Oak Ridges Moraine intersects Rice Lake. To the north are Drumlinized uplands, referred to as the ''Peterborough drumlin field''. GEOLOGICAL ORIGINS See Also: Origin of the Oak Ridges Moraine The "Oak Ridges Moraine" probably formed in the Late Wisconsonian glacial period. Ice melt from the Niagara Escarpment flowed into the western boundaries of the moraine, wherein conduits beneath the ice expanded to form a west-to-east passage between the main Laurentide Ice Sheet and a mass of ice in the Lake Ontario basin. Stratified sediment was deposited rapidly on the high-relief Erosional surface. Up to 150 m in some areas, the deposits occurred on surfaces defined by highly eroded channels and Drumlin uplands. The channel tunnels were primarily created by the erosion from glacial rivers, a typical process before moraine formation. Characteristic of this moraine is the transition of deposition layers from glaciofluvial to glaciolacustrine. Sedimentary glaciofluvial areas form the core of the Oak Ridges Moraine, though restricted to subglacial cavity fills of confined Subaqueous Fan s. Overlaying this core is a glaciolacustrine sedimentary layer that is younger and topographically lower, principally in the Delta and Basin areas of the moraine. In the late stages of its development, random unstratified accumulation (''known as s'') within the moraine sediments. However, the lowest beds in the moraine may have experienced synchronous sedimentation. HYDROLOGY See Also: Hydrography of the Oak Ridges Moraine A number of features comprise the hydrological system of the Oak Ridges Moraine:1
This hydrological system is inter-twined with a regional flow systems not bound by the morphological limits of the moraine.2 For this reason, environmentalists and researchers promote an aggressive protection strategy extending beyond the moraine, thus ensuring a contiguously protected hydrological system. The preservation of aquifers is especially important, since they are used as a primary water source by some municipalities located on or near the moraine. These aquifers also discharge into tributaries that are the headwaters of creeks and rivers which eventually flow into Lake Simcoe, Lake Scugog and Lake Ontario. The Oak Ridges Moraine Conservation Act stipulates that any development which targets the moraine or nearby areas must satisfy several conditions, most prominently that each development leave a buffer zone of 30 m between it and any hydrological feature; for a kettle lake, this measure is from the edge of the lake's catchment area. The Oak Ridges Moraine's hydrological system is a major constituent of the Humber Watershed , so that any impact on this system will be of concern. A specific concern is urbanization, which affects water quality by increasing its load of metals and organic contaminants.3 A study by Cook et al (1985) found an increase in mean annual runoff, instantaneous discharge, and hydrograph peak flow as a result of urbanization: "...changes in land use coincided with changes in volumetric and time distribution aspects of hydrologic response." RESEARCH ON THE MORAINE In 1829, John Bigsby conducted the first investigation of the moraine.4 He noted the elevation, and styled the area ''Oak Ridge'', identifying the portion of moraine north of Toronto . Еhe moraine's extent was not established until 1863 when William Logan conducted his Geological Survey Of Canada . Taylor formally defined the landform as the Oak Ridges Moraine in 1913. He described its extent to be from King and Maple in the west to the Trent River in the east. He also theorized that its origin was overlapping, interlobate glaciation retreat, between the Lake Ontario Lobe and the older Lake Simcoe Lobe . This has become the accepted explanation for the moraine's development, though research in the 1970s suggested the moraine may not be interlobate. Research conducted in the 1990s reveals that the moraine has multiple origins: its eastern area has subglacial depositions (Gorrell and McCrae, 1993); early parts of the moraine were deposited in an esker (Brennand and Shaw, 1994); and that the moraine is not continuous, but is composed of multiple depositional environments: subglacial, ice-marginal and proglacial lacustrine (Barnett et al, 1998). Current research efforts on the moraine are quite extensive. Because of the political implications of development on the moraine, and because its aquifers are a source of potable water in numerous communities, both federal and provincial governments have invested resources towards research on the moraine. The Geological Survey Of Canada and Ontario Geological Survey both investigate hydrostratigraphy and hydrology throughout the moraine. Palaeo-Indian hunter-gatherers were in this area between 10,000 - 7,000 BC. The oldest artifact found in what is now Richmond Hill, Ontario, from these people, was a stone scraper about 40 mm long, at the Mortson Site, near Leslie Street and 19th Avenue. Other artifacts were found in a settlement site on the eastern shore of Lake Wilcox. Archaic Iroqouis artifacts circa 1800 BC have also been found at the Silver Stream site, near the headwaters of the Rouge River on Leslie Street just north of Major Mackenzie Drive, and at the Esox site, on the eastern shore of Lake Wilcox. POLITICAL ACTION See Also: Politics of the Oak Ridges Moraine
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