scholarly journals Geochemistry of surficial sediment cores, Greater Toronto Area, southern Ontario

2018 ◽  
Author(s):  
R D Knight ◽  
D A J Stepner ◽  
R E Gerber ◽  
S Holysh ◽  
H A J Russell
Keyword(s):  
Sediment Cores ◽  
Surficial Sediment ◽  
Southern Ontario ◽  
Greater Toronto Area

scholarly journals Geochemistry of surficial sediment cores, Brantford-Woodstock area, southern Ontario

2018 ◽  
Author(s):  
R D Knight ◽  
D A J Stepner ◽  
A F Bajc ◽  
H A J Russell
Keyword(s):  
Sediment Cores ◽  
Surficial Sediment ◽  
Southern Ontario

scholarly journals Geochemistry of surficial sediment cores, southern Simcoe County, southern Ontario

2018 ◽  
Author(s):  
R D Knight ◽  
A F Bajc ◽  
R P M Mulligan ◽  
M J Moroz ◽  
H A J Russell
Keyword(s):  
Sediment Cores ◽  
Surficial Sediment ◽  
Southern Ontario

scholarly journals Geochemistry of surficial sediment cores, southern Ontario: data release

2018 ◽  
Author(s):  
D A J Stepner ◽  
A F Bajc ◽  
A K Burt ◽  
R D Knight ◽  
H A J Russell
Keyword(s):  
Sediment Cores ◽  
Surficial Sediment ◽  
Southern Ontario ◽  
Data Release

scholarly journals Lithology and geochemistry of sediment cores, Pickering area, southern Ontario

2021 ◽  
Author(s):  
R D Knight ◽  
D A J Stepner ◽  
B A Kjarsgaard ◽  
D R Sharpe ◽  
H Crow ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Southern Ontario

scholarly journals High-resolution quantification of atmospheric CO<sub>2</sub> mixing ratios in the Greater Toronto Area, Canada

2018 ◽  
Vol 18 (5) ◽  
pp. 3387-3401 ◽  
Author(s):  
Stephanie C. Pugliese ◽  
Jennifer G. Murphy ◽  
Felix R. Vogel ◽  
Michael D. Moran ◽  
Junhua Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Natural Gas ◽  
Co2 Emissions ◽  
Time Of Day ◽  
Model Framework ◽  
Gas Combustion ◽  
Southern Ontario ◽  
Mixing Ratios ◽  
Greater Toronto Area ◽  
Natural Gas Combustion

Abstract. Many stakeholders are seeking methods to reduce carbon dioxide (CO2) emissions in urban areas, but reliable, high-resolution inventories are required to guide these efforts. We present the development of a high-resolution CO2 inventory available for the Greater Toronto Area and surrounding region in Southern Ontario, Canada (area of  ∼ 2.8 × 105 km2, 26 % of the province of Ontario). The new SOCE (Southern Ontario CO2 Emissions) inventory is available at the 2.5 × 2.5 km spatial and hourly temporal resolution and characterizes emissions from seven sectors: area, residential natural-gas combustion, commercial natural-gas combustion, point, marine, on-road, and off-road. To assess the accuracy of the SOCE inventory, we developed an observation–model framework using the GEM-MACH chemistry–transport model run on a high-resolution grid with 2.5 km grid spacing coupled to the Fossil Fuel Data Assimilation System (FFDAS) v2 inventories for anthropogenic CO2 emissions and the European Centre for Medium-Range Weather Forecasts (ECMWF) land carbon model C-TESSEL for biogenic fluxes. A run using FFDAS for the Southern Ontario region was compared to a run in which its emissions were replaced by the SOCE inventory. Simulated CO2 mixing ratios were compared against in situ measurements made at four sites in Southern Ontario – Downsview, Hanlan's Point, Egbert and Turkey Point – in 3 winter months, January–March 2016. Model simulations had better agreement with measurements when using the SOCE inventory emissions versus other inventories, quantified using a variety of statistics such as correlation coefficient, root-mean-square error, and mean bias. Furthermore, when run with the SOCE inventory, the model had improved ability to capture the typical diurnal pattern of CO2 mixing ratios, particularly at the Downsview, Hanlan's Point, and Egbert sites. In addition to improved model–measurement agreement, the SOCE inventory offers a sectoral breakdown of emissions, allowing estimation of average time-of-day and day-of-week contributions of different sectors. Our results show that at night, emissions from residential and commercial natural-gas combustion and other area sources can contribute > 80 % of the CO2 enhancement, while during the day emissions from the on-road sector dominate, accounting for > 70 % of the enhancement.

Isotopic and geochemical composition of marl lake waters and implications for radiocarbon dating of marl lake sediments

1983 ◽  
Vol 20 (4) ◽  
pp. 599-615 ◽  
Author(s):  
J. V. Turner ◽  
P. Fritz ◽  
P. F. Karrow ◽  
B. G. Warner
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Sediment Cores ◽  
Geochemical Composition ◽  
Radiocarbon Dates ◽  
Southern Ontario ◽  
Suitable Material ◽  
Geochemical Parameters ◽  
Marl Lake ◽  
Lake Waters

Radiocarbon dates on organic and calcareous fractions of sediment cores from marl lakes may yield anomalous ages due to the assumption of a constant hardwater correction factor along the sediment sequence. A study of eight marl lakes in southern Ontario that are actively precipitating calcium carbonate was conducted in order to assess those isotopic and aqueous geochemical parameters in modern lakes that may be utilized to estimate the history and extent of variations in the hardwater effect along such sediment sequences. Results show an increase in the δ13C composition of lake DIC (dissolved inorganic carbon) as approach to isotopic equilibrium with atmospheric CO2 occurs. Differences in the extent to which this equilibrium is established also appear responsible for observed differences in the 14C activity of DIC between lakes of as much as 20 pmc (percent modern carbon). These variations have been related to the relative residence times of water in each lake by examination of their corresponding seasonal variations in 18O and 2H content. Consequently δ13C and δ18O of marl and molluscs have been used to identify variations in the hardwater effect along the sediment profile. A profile of radiocarbon dates on marl from Little Lake in southern Ontario shows satisfactory agreement with an independently determined pollen chronology. Where certain criteria are met, marl deposits appear to be suitable material for establishing Quaternary chronology.

scholarly journals The spatial legacy of Australian mercury contamination in the sediment of the Molonglo River

Elem Sci Anth ◽  
2020 ◽  
Vol 8 ◽  
Author(s):  
Dylan Stinton ◽  
Larissa Schneider ◽  
Sara Beavis ◽  
Janelle Stevenson ◽  
William A. Maher ◽  
...  
Keyword(s):  
New South ◽  
Sediment Cores ◽  
New South Wales ◽  
Surficial Sediment ◽  
Mercury Contamination ◽  
Mine Site ◽  
Factors Influencing ◽  
South Wales ◽  
Chemical Factors ◽  
Physical And Chemical

Mercury (Hg) contamination is an environmental concern as a by-product of legacy mining in Australia. Here we investigate the spatial and temporal distribution of Hg in the Molonglo River system in New South Wales, Australia, and assess the physical and chemical factors influencing that distribution. Mercury concentrations in sediment cores were measured in conjunction with 210Pb and 137Cs dating to establish historical contamination. This was done at the source mine site of Captains Flat, New South Wales, and the system’s sink in Lake Burley Griffin, Australian Capital Territory. Additionally, surficial sediment Hg concentrations along the Molonglo River were analyzed to determine the spatial distribution of Hg. Analytical results showed the primary physical and chemical factors influencing Hg dispersion to be distance, total organic matter, and the presence of iron oxides and oxyhydroxides. The highest Hg concentrations were near the mine site at Captains Flat and decreased significantly with distance. Sediment core analyses in both Captains Flat and the lake showed reductions in Hg concentrations toward surficial sediment layers. It is suggested government-funded rehabilitation programs are playing a part in reducing the release of metal contamination.

scholarly journals Regional geological mapping of the Oak Ridges Moraine, Greater Toronto area, southern Ontario

1999 ◽  
Author(s):  
D R Sharpe ◽  
P J Barnett ◽  
H A J Russell ◽  
T A Brennand ◽  
G Gorrell
Keyword(s):  
Geological Mapping ◽  
Southern Ontario ◽  
Oak Ridges Moraine ◽  
Greater Toronto Area
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