<P> Detailed Nd isotopic mapping in the southwestern Grenville Province between North Bay, Ontario, and Temiscaming, Quebec has revealed the precise trend of the proposed Penokean-aged suture discovered during reconnaissance isotopic mapping by Dickin and McNutt (1989). </p> <p> Lithotectonic domains proposed by Easton (1989} for the greater North Bay area are cross-cut by the suture. As presently located, the Tilden-Tomiko domain boundary effects no apparent offset of the suture which would be expected during low angle differential Grenville thrusting. Although a lack of apparent offset suggests these domains are not significant Grenville structures a definitive answer must await more precise mapping of their boundaries. There appears to be some potential for unravelling aspects of Grenville tectonism through such cross-cutting relationships. </p> <p> In the North Bay-Temiscaming area the full model age transition from ca 1.90 Ga to ca 2.70 Ga is negotiated in stepwise fashion through metasediments of intermediate Nd model age spanning an area from a few kilometers to a few tens of kilometers in width. This suggests the suture boundary is better described as a suture zone. Presently two groups of intermediate aged metasediments are recognized (1} a 2.00-2.39 Ga group and ( 2) a 2. 40-2.60 Ga group. These age groups correspond to rocks of two different lithologies separated along strike of the suture in the Temiscaming and North Bay areas respectively. Although the ages of metasediments comprising the suture zone more or less spans the entire interval between 1.90 and 2.70 Ga, there is no well defined transect wherein the whole range of intermediate aged crust is recorded within a single rock type. Therefore a 'splitting' rather than 'lumping' approach is deemed justified for the intermediate aged crust until provenance studies using zircons can be undertaken to show in a definitive manner whether or not the two groups are related in a genetic sense. </p> <p> The absence of plutonism with crystallization ages between 2.00 and 2.60 Ga in the North Bay-Temiscaming area suggests that metasediments of the suture zone acquired their model age from sedimentological mixing between crust of Archean (ca 2.70 Ga) and Proterozoic (ca 1.90 Ga) provenance. The arrangement of mixed provenance metasediments coincident with the suture suggests a genetic relationship. It is proposed that the mixed provenance metasediments are part of a foreland basin assemblage which formed in response to downloading of the cratonal edge by the combined effect of an overriding island arc and the attempted subduction of the Superior craton. </p> <p> Major element analyses show that mixed provenance and arc derived sediments of the proposed foreland basin display a wide range in their maturity. This is consistent with the foreland basin environment where sediments can be reworked to varying degrees in response to tectonically controlled local sea level fluctuations. Contrasting the dynamic environment of the foreland basin the belt of Archean crust north of the suture with model ages of ca 2.72 Ga shows a very restricted range of reworking implying a uniform depositionary environment e.g., deep water passive margin. </p> <p> North of the field area a lobe of Archean crust extends into the Grenville Province, anchored by the Pontiac Group on the northern margin of the Grenville Front (GF), and consisting in part of the parautocthonous Red Cedar Lake Gneiss south of the GF. The full expression of the Archean lobe within the Grenville Province and north of the North Bay Temiscaming field area is unknown, however, preliminary results from Nd isotopic mapping suggest that Archean crust between the suture and the Grenville Front Tectonic Zone (GFTZ) may be part of, or, derived from this Archean parautocthonous lobe. Archean provenance crust north of the field area defines a relatively homogeneous belt of crust with ca 2.72 Ga model ages and a whole rock Sm-Nd isochron age of 2.77 Ga. This is in sharp contrast to the heterogeneity of model ages displayed by Archean crust further west, between the suture (French River area) and the Grenville Front near Sudbury, Ontario (Dickin et al., 1989). Here, the Archean foreland may owe its peculiar heterogeneity to mixing between 2. 72 Ga crust and 2. 4 Ga Huronian volcanics andjor 1. 7 Ga Kilarnian juvenile crust (Dickin et al., 1990). Evidence for the presence of these crustal endmembers in the North Bay Temiscaming area is lacking. </p> <p> Finally, the presence of a suture zone consisting of mixed provenance metasediments is the best evidence yet in support of the suture hypothesis explanation for the model age transition as opposed to juxtaposition of two crustal age domains by Grenville thrusting. </p> / Thesis / Bachelor of Science (BSc)

<p> Large high density populations, up to 3,000/m^2 of the bivalve Macoma balthica inhabit the muddy intertidal areas in the Bay of Fundy, Nova Scotia. The fecal pellets produced by Macoma b. are resistant to breakdown. Off Spencer's Point, the pellets are transported via small intertidal channels away from the shore onto a sand bar, at low tide. At high tide the channels act as traps for fecal pellets. The pellets breakdown over the sand bar at high tide, but a large proportion of the pellet remains in suspension as a mucous bound mud agglomerate. In an area of 2000 Macoma b./m^2, the rate of fecal pellet production is approximately 1 Kg dry wt/m^2/yr. </p> <p> The rate of pseudofecal production increases with water turbidity. The rate of sediment reprocessing is approximately 9 Kg dry wt. of sediment/m^2/yr., or a layer of wet sediment approximately 3.3 cm. deep. </p> <p> The Macoma b. in Cobequid Bay are largely deposit feeding. In areas of high population density and coarser sediment, this depletes the surface of sediment mud and fine sand. The influx of sediment necessary to sustain such a population is, in part, pseudofecal material from Macoma b. populations higher on the mud flats. </p> / Thesis / Bachelor of Arts (BA)

<p> This study focuses on the relations hip between ice cover and wind frequency, wind speed and air temperature. Results showed that there are four distinct MELT periods along the west coast of Hudson Bay. With a standardized MELT period, stations are generally higher correlated with their southern neighbours. Onshore wind frequencies increased signficantly from the NOMELT to the MELT period, and were associated with air temperatures 3 to 4 degrees Celsius colder than those of offshore winds. </p> <p> Mean air temperature was most highly correlated with percent ice cover. Ice cover was most strongly correlated with mean air temperature at Chesterfield Inlet and least so at Churchill. Thus, freeze-up and melt at Chesterfield Inlet are most strongly influenced by air temperature whereas at Churchill, other factors, presumably wind direction and currents, strongly influence the ice cover. Ice cover was most strongly influenced by air temperature during the NOMELT period. This shows that cold temperatures hasten freezeback more than warm temperatures hasten MELT. </p> / Thesis / Bachelor of Arts (BA)

<p> Processes affecting the transportation and destruction of empty valves of the pelecypods Mya arenaria and Macoma balthica, were examined within the intertidal zone off Portapique Beach in the Minas Basin(Bay of Fundy). It was found that valve transport was away from shore within channels and eastward alongshore on the flats. It was observed that the rate of transport of left valves and small valves was greater than right valves large valves respectively. Transported valves are preferential oriented by currents of the flood and ebb tides and those within intertidal channels. Channel migration does not appear to be of significance in removing empty valves from these intertidal sediments. The loss valves from within the sediment is attributed to an unknown 'escape' mechanism. Once free of the sediment, valves are transported, weakened by boring thallophytes and mechanically destroyed during transport.</p> / Thesis / Bachelor of Science (BSc)

Conventional nonpoint source pollution policies encourage the adoption of conservation practices to reduce nonpoint source pollutants by paying a portion of the cost to install best management practices. Alternative financial incentive programs, such as payment for environmental services (PES) programs, aim to improve program effectiveness by paying directly for the quantity of environment services provided, but implementing PES programs to reduce nonpoint source pollution has been challenging given the costs and technical feasibility of measuring pollutant outcomes. Bioreactors, engineered sinks that convert biologically available forms of nitrogen into an inert form (N_2), have recently been proposed to treat and remove legacy nitrogen from springs (Easton et al., 2019). Since nitrogen removal can be directly measured, there is potential to implement an outcome-based PES program. Little information exists on the costs and risks sellers face under such a program or the impact of contractual conditions. This research applies Monte Carlo simulation to a case study bioreactor in the Chesapeake Bay Watershed to estimate the financial risks and rewards to N removal service providers under different outcome-based PES contractual conditions. Results indicate that under a fifteen-year contract term and price of $25/lb/yr of nitrogen removal, outcome-based PES for denitrifying bioreactors has a high chance of generating positive financial outcomes for a commercial size case study bioreactor that removes an average of 1,279 lbs of N annually. / Master of Science / Conventional policies to reduce diffuse water pollutants encourage the adoption of conservation practices to reduce diffuse water pollutants by paying a portion of the cost to install remedial practices or technologies. Payment for environmental services (PES) programs, an alternative to conventional policies, aims to improve program effectiveness by paying directly for the quantity of environment services provided. However, implementing PES programs to reduce diffuse water pollution has been challenging given the costs and technical feasibility of measuring pollutants and outcomes of remedial efforts. Bioreactors, engineered sinks that convert the diffuse water pollutant nitrogen into a non-pollutive form, have recently been proposed to remove legacy nitrogen from springs (Easton et al., 2019). Using bioreactors, nitrogen removal can be directly measured, so there is potential for an outcome-based PES program. Little information exists on the costs and risks sellers face under such a program or the impact of contractual conditions. This research applies financial simulation to a case study bioreactor in the Chesapeake Bay Watershed to estimate the financial risks and rewards to N removal service providers under different outcome-based PES contractual conditions. Results indicate that under a fifteen-year contract term and price of $25/lb/yr of nitrogen removal, outcome-based PES for denitrifying bioreactors has a high chance of generating positive financial outcomes for a commercial size case study bioreactor that removes an average of 1,279 lbs of N annually.

Sediment is a major impairment in many streams and rivers in the drainage basins along the northern Gulf of Mexico. The use of geospatial technologies improves assessment and decision making for the management of environmental resources and conditions for coastal watersheds. This research focuses on the development of a conceptual qualitative model enhanced with expert input for the assessment of soil erosion potential in coastal watersheds. The conceptual model is built upon five layers (slope, precipitation, soil brightness or exposure, Kactor, and stream density) like those in a standard numerical soil loss model such as the Revised Universal Soil Loss Equation (RUSLE). The conceptual model produced a continuous surface to index erosion potential. Pearson’s correlation coefficient was used to identify variable sensitivity. The model was most sensitive to Kactor variable, followed by soil brightness, stream density, and slope. The model was not sensitive to the precipitation variable due to the lack of variability across the watershed. Expert input was added to the conceptual model for erosion potential with the Analytical Hierarchy Process (AHP). The AHP is used to value the importance of criteria, providing a quantitative weight for the qualitative data. The expert input increased the overall importance of topographic features and this increased cell counts in the upper erosion potential classes. The AHP weights were altered in 1% increments ranging from plus to minus 20% producing 201 unique runs. A quartile analysis of the runs was used to define areas of model agreement. The quartile analysis allowed for the application of an analysis mask to identify areas of increased erosion potential for improved management related decisions. The conceptual and AHP erosion potential output data, including watershed management priority rankings, were published as web mapping services for story map development as a transition to a decision support system. The limits of the story map to allow user interactions with model output rendered an unacceptable platform for decision support. The story map does offer an alternative to static reports and could serve to improve dissemination of spatial data as well as technical reports and plans like a watershed management plan.

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