Geochemical evolution of uraniferous soda lakes in Eastern Mongolia |
| |
| Authors: | Benjamin S Linhoff Philip C Bennett Tamir Puntsag Ochir Gerel |
| |
| Institution: | (1) Department of Geological Sciences, The University of Texas at Austin, 1 University Station, C1100, Austin, TX 78712, USA;(2) Central Laboratory of Environment and Metrology, NAMEM, P.O. BOX-150, Ulaanbaatar-36, Mongolia;(3) Mongolian University of Science and Technology, CPO, Box 249, Ulaanbaatar, 211213, Mongolia;(4) Present address: Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D469, Los Alamos, NM 87545, USA |
| |
| Abstract: | Extremely high concentrations of uranium (U) were discovered in shallow, groundwater-fed hyperalkaline soda lakes in Eastern
Mongolia. A representative groundwater sample in this area is dilute and alkaline, pH = 7.9, with 10 mM TIC and 5 mM Cl−. In contrast, a representative lake water sample is pH ~ 10 with TIC and Cl− each more than 1,000 mM. Groundwater concentrations of U range from 0.03 to 0.43 μM L−1. Lake water U ranges from 0.24 to >62.5 μM, possibly the highest naturally occurring U concentrations ever reported in surface
water. Strontium isotopes 87Sr/86Sr varied in groundwaters from 0.706192 to 0.709776 and in lakes 87Sr/86Sr varied from 0.708702 to 0.709432. High concentrations of U, Na, Cl−, and K correlate to radiogenic Sr in lake waters suggesting that U is sourced from local Cretaceous alkaline rhyolites. Uranium-rich
groundwaters are concentrated by evaporation and U(VI) is chelated by CO3−2 to form the highly soluble UO2(CO3)3−4. Modeled evaporation of lakes suggests that a U-mineral phase is likely to precipitate during evaporation. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
