scholarly journals Quaternary Geology, Blue Lake - Rowan Lake area, Lake of the Woods Region, northwestern Ontario

1988 ◽  
Author(s):  
G Minning
1994 ◽  
Vol 51 (5) ◽  
pp. 1147-1161 ◽  
Author(s):  
Malcolm Stephenson ◽  
Gregory Mierle ◽  
Ronald A. Reid ◽  
Gerald L. Mackie

A simple method for the assessment of littoral benthic macroinvertebrate (BMI) assemblages in lakes was developed at the Experimental Lakes Area (ELA) in northwestern Ontario and applied to 64 lakes in central Ontario. The presence (1) or absence (0) of BMI taxa was established at five sites on each lake, using a kick-and-sweep net technique. Summing presence/absence scores across sites ranked the importance of each taxon in each lake on a scale of 0 to 5. Relationships between the BMI assemblages were assessed using nonmetric multidimensional scaling (NMDS), based upon the Kendall's τ correlation matrix. Correlations between NMDS dimension 1 and 2 scores and environmental variables identified factors that may structure BMI assemblages. The BMI assemblages of three experimentally acidified and seven reference lakes at the ELA were correlated strongly with lake pH. The BMI assemblage structure of central Ontario lakes was predicted by lake area and sensitivity to acidification (NMDS dimension 1) and by lake elevation (NMDS dimension 2). The BMI assemblages of small or Ca-poor and acidic lakes include fewer oligochaetes, mayflies, and Cryptochironomus and Stictochironomus (chironomids) and more Odonata, Trichoptera, Chironomus, Conchapelopia, Microtendipes, and Procladius (chironomids), and Crangonyx (Amphipoda) than other central Ontario lakes.


1977 ◽  
Vol 14 (9) ◽  
pp. 1980-1990 ◽  
Author(s):  
J. A. Donaldson ◽  
Richard W. Ojakangas

An Archean conglomerate in the North Spirit Lake area of northwestern Ontario contains rare orthoquartzite pebbles. Detailed study of these pebbles shows that mineralogically they are very mature, consisting of as much as 99.8 percent quartz and a heavy mineral suite of zircon, tourmaline, and apatite. Textures are typically bimodal, characterized by rounded sand-sized quartz grains set in a 'matrix-cement' of thoroughly recrystallized finer quartz grains. These orthoquartzite pebbles provide the first definite evidence for local tectonic stability of the Canadian Shield before deposition of the immature sedimentary rocks that form part of an Archean (>2.6 Ga) greenstone belt of the Superior Province.


2013 ◽  
pp. 1328-1344
Author(s):  
John W. Norder ◽  
Jon W. Carroll

This study examines the role of rock art in the construction of Woodland Period (300 BC to AD 1700) hunter-gatherer landscapes in the Lake of the Woods region of northwestern Ontario. The authors examine the distribution of documented pictograph sites relative to the locations of rock formations where the geologic conditions would have favored the placement of pictographic rock art but are absent. Point pattern analysis, Monte Carlo simulation, and least cost path analysis were used to analyze the findings. The authors suggest that pictograph sites were placed at points on the landscape along water routes to facilitate information exchange among highly mobile hunter-gatherers.


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