Brine-rock interaction in the Athabasca basement (McArthur River U deposit, Canada): consequences for fluid chemistry and uranium uptake
Year: 2010
Type: article
Abstract: Terra Nova, 22, 303–308, 2010 The nature of uranium source rocks, transport conditions and deposition processes are still highly controversial for world-class unconformity-related U deposits. This article presents the first detailed chemistry of brines associated with the giant McArthur River U deposit, Canada. LA-ICP-MS analysis of individual fluid inclusions suggests mixing between a Na–Ca–Mg–K–Sr–Ba brine and a Ca–Mg–Na–K–Sr–Ba brine. The brines share a common origin (evaporated seawater) and show evidence for contrasting interaction with basement rocks. The Na-rich brine lost Mg and K in alteration haloes around U ores, while the Ca-rich brine results from Na–Ca exchange and Sr–Ba gain. U concentrations (0.3–530 μg g−1) are anomalously high compared with usual basinal fluids, this indicating that U uptake occurred within basement rocks. The two brine end-members have mixed within the main U deposit area, which could be one of the major driving forces for U deposition.
Source: Terra Nova
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1502018782