Saline groundwaters and brines in the Canadian Shield: Geochemical and isotopic evidence for a residual evaporite brine component

Journal Article · Tue Mar 01 00:00:00 EST 1994 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(94)90551-7· OSTI ID:7040690

Bottomley, D J ^[1]; Gregoire, D C ^[2]; Raven, K G ^[3]

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1. Atomic Energy Control Board, Ontario (Canada)
2. Geological Survey of Canada, Ottawa, Ontario (Canada)
3. Raven Beck Environmental Ltd., Ottawa, Ontario (Canada)

Saline Ca-Na/Cl type groundwaters and brines sampled in deep mines over an extensive area of the Canadian Precambrian Shield have elevated Br/Cl ratios which may indicate that the chlorinity of these waters was derived from the infiltration of residual evaporitic brines, remnants of the great marine incursion of the Paleozoic era. Boron concentrations in these waters are generally low (i.e., < [approximately] 2 mg/L) relative to seawater or Alberta Basin Devonian formation waters. However, the [sup 11]B/[sup 10]B ratios of these waters are significantly greater than the average value for continental crustal rocks with the highest values ([approximately]4.19) approaching that of present-day seawater (4.20). Moreover, the boron isotopic ratios generally trend to higher values with increasing chlorinity which supports the conclusion from the Br-Cl relationship that most of the chloride in shield brines is of marine origin, rather than a product of water/rock interactions. If this is correct, crystalline rocks must then be sufficiently permeable on a regional scale to have allowed the brine to infiltrate to depths of several kilometers where it now resides. The presence of saline groundwaters in crystalline has important implications for the Canadian Nuclear Fuel Waste Management Program, which proposes disposal of waste fuel in a repository constructed at a depth of 500-1000 m in plutonic rock.

• OSTI ID: 7040690
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 58:5; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BRINES
ORIGIN
CANADA
RADIOACTIVE WASTE DISPOSAL
GROUND WATER
SALINITY
RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
BROMINE
CALCIUM
CHLORINE
MAGNESIUM
PLUTONIC ROCKS
SODIUM
ALKALI METALS
ALKALINE EARTH METALS
DEVELOPED COUNTRIES
ELEMENTS
HALOGENS
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
MANAGEMENT
MATERIALS
METALS
NONMETALS
NORTH AMERICA
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE MANAGEMENT
ROCKS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER
052002* - Nuclear Fuels- Waste Disposal &amp; Storage