The geochemistry, age, and origin of groundwater in a mafic pluton, East Bull Lake, Ontario, Canada

Evolution of groundwater chemical composition by plagioclase hydrolysis in Norwegian anorthosites

“…According to Jacks (1973), areas with much bare rock were likely to have low CO 2 concentrations in the groundwater. Bottomley et al (1990) cast doubt on whether silicate weathering is an adequate mechanism to explain the evolution of sodium bicarbonate waters in the Canadian Shield, and consequently favoured an ion exchange mechanism. They argued that, in the transition from Ca-HCO 3 to Na-HCO 3 waters, around 2 mmol/L (46 mg/L) Na is acquired.…”

“…5d and e) that in extremely evolved, high pH waters, where carbonate species are absent, calcium dominated waters may eventually develop. Intriguingly, Bottomley et al (1990) and Gascoyne and Kamineni (1993) described the evolution of groundwaters with depth in the Canadian shield. The most typical evolutionary sequence progressed from Ca-HCO 3 , through Na-HCO 3 to Na-Cl and Ca-Cl.…”

“…Indeed, hydrochemical evolution pathways culminating in soft, sodium bicarbonate waters of high pH and low calcium concentration are observed in a remarkably wide range of aquifers throughout the world, such as the British Lincolnshire Limestone (Edmunds, 1981), a gabbro-anorthosite pluton in Ontario (Bottomley et al, 1990), Dutch Quaternary coastal sediments (Appelo and Postma, 1996), the Coal pH and Eh were measured in the field. Alkalinity was titrated in the field to pH 4.3 and is cited as mEq/L.…”

Radiogenic helium in shallow groundwater within a clay till, southwestern Ontario

“…If the release occurs at the rate of U and Th series decay, then measurable amounts of 4 He will accumulate after about 1000 years, and theoretically continue for millions of years. He-4 has thus traditionally been used as a groundwater tracer over a long timescale [Andrews and Lee, 1979;Marine, 1979;Torgersen, 1980;Andrews et al, 1982;Torgersen and Ivey, 1985;Balderer and Lehmann, 1989;Bottomley et al, 1990;Ballentine et al, 1991;Mazor and Bosch, 1991;Stute et al, 1992;Marty et al, 1993]. However, concentrations of 4 He in groundwater that are larger than can be explained by U and Th decay and the water age have been well documented [e.g., Torgersen and Ivey, 1985;Solomon et al, 1996] and previously interpreted as the result of 4 He diffusion from older underlying units (external source).…”

Carbon-13 in groundwater from English and Norwegian crystalline rock aquifers: a tool for deducing the origin of alkalinity?

“…Phase (iv) At greater depth and prolonged residence time, deep brines (Gascoyne and Kamineni 1993;Bottomley et al 1990) of sodium/calcium sulphate/chloride composition. Banks and Frengstad (2006) noted that water types representing Phases (i) to (iii) could be found in shallow Norwegian crystalline bedrock aquifers, even in relatively simple aquifer lithologies such as anorthosite (Table 1), which is dominated by plagioclase feldspar.…”