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TitleSilica chimneys formed by low-temperature brine spring discharge
AuthorGrasby, S E; Bezys, R; Beauchamp, B
SourceAstrobiology vol. 9, no. 10, 2009 p. 931-941,
Alt SeriesEarth Sciences Sector, Contribution Series 20090200
PublisherMary Ann Liebert Inc
Mediapaper; on-line; digital
File formatpdf
NTS63B/04; 63B/05; 63B/12; 63B/13; 63C; 63F/01; 63F/02; 63F/03; 63F/04; 63G/04
AreaMafeking; Lake Winnipegosis; Dawson Bay; Sagemcy Bay
Lat/Long WENS-101.5000 -99.5000 53.2500 52.0000
Subjectsgeochemistry; hydrogeology; hydrothermal systems; hydrothermal deposits; hydrothermal alteration; silica; cherts; brine; hot springs geochemistry; springs; thermal springs; salt springs; geochemical surveys; geochemical analyses; Williston Basin; Mafeking Quarry
Illustrationslocation maps; photographs; cross-sections; stratigraphic columns
ProgramGroundwater Mapping Program
AbstractVertical pipes comprised of loose silica and lined by chert nodules have been observed in the abandoned Mafeking Quarry in central Manitoba, Canada. Discovery of microfossils within these features of the same age as the carbonate host rock indicates that they are a dissolution=replacement structure rather than infill of karst features by younger sediments. These features occur on the low thermal maturity edge of the intercratonic Williston Basin, are not associated with any known tectonic or hydrothermal activity, and show no sign of localized discharge of high-temperature fluids. Modern low-temperature brine springs with silica-filled discharge channels occur nearby, which suggests the silica chimneys are relic spring channels. Geochemical models have shown that dissolution=replacement reactions would be expected due to mixing of brine spring water with shallow groundwater in the region. Results indicate that silica pipe features in the rock record cannot be assumed to be indicative of hydrothermal activity. At the same time, results increase the astrobiological significance of low-temperature siliceous deposits.