Authentication email has already been sent, please check your email box: and activate it as soon as possible.
You can login to My Profile and manage your email alerts.
If you haven’t received the email, please:
|
|
There are 3 papers published in subject: > since this site started. |
Results per page: |
Select Subject |
Select/Unselect all | For Selected Papers |
Saved Papers
Please enter a name for this paper to be shown in your personalized Saved Papers list
|
1. Uranium-series disequilibria in the groundwater of the Shihongtan sandstone-hosted uranium deposit, NW China | |||
Min Maozhong,Peng Xinjian,Qiao Haiming | |||
Earth Science 11 February 2010 | |||
Show/Hide Abstract | Cite this paper︱Full-text: PDF (0 B) | |||
Abstract:Study on uranium-series disequilibria of groundwater is first reported here in China. Uranium concentration and uranium isotopes 238U,234U and 230Th for groundwaters, spring waters and lake water collected from the Shihongtan sandstone-hosted uranium ore district and in the surrounding area, NW China, were determined. The results show that the groundwaters from the oxidizing aquifer with high dissolved oxygen concentration (O2) and oxidation-reduction potential (Eh) have U enrichment. High U concentration of some groundwaters might result from intersected and dissolved old U orebody by oxidizing or saline groundwaters, inducing U-series disequilibrium. Uranium was most likely precipitated at the reducing barrier as uraninite or absorbed onto the heterochronogenous mineral and organic material particles. It is supported by the fact that new U orebody is locally forming in the sandstone-hosted reducing aquifer. The 234U/ 238U, 230Th/ 234U and 230Th/238U activity ratios (ARs) for most water samples are obvious deviations from secular equilibrium (0.27–2.86), indicating the presence of water–rock/ore interactions during the last 1 Ma and probably longer and 234U enrichment in the waters. The 234U/238U AR increases approximately with the decrease in U concentration of the waters, suggesting that mixing of two water sources may occur in the aquifer. This is consistent with the fact that most of U orebodies in the deposit have a tabular shape originated from mixing between a relatively stagnant saline fluid and a more rapidly flowing uranium-bearing meteoric water. | |||
TO cite this article:Min Maozhong,Peng Xinjian,Qiao Haiming. Uranium-series disequilibria in the groundwater of the Shihongtan sandstone-hosted uranium deposit, NW China[OL].[11 February 2010] http://en.paper.edu.cn/en_releasepaper/content/40167 |
2. Biodegradation of hydrocarbon in Dongsheng sandstone-hosted uranium deposit,North China | |||
Min Maozhong,Wang Jinping,Xie Hongbing | |||
Earth Science 09 February 2010 | |||
Show/Hide Abstract | Cite this paper︱Full-text: PDF (0 B) | |||
Abstract:Organic geochemistry were studied for the ores and altered, unaltered host sandstones at the Dongsheng sandstone-hosted uranium deposit in the Ordos Basin, North China. Interlayer alteration of the host sandstone in the Dongsheng deposit is different from one in the other sandstone-hosted uranium deposits of China and may be divided into four geochemical zones, i.e., the unaltered grey host sandstone in the reducing zone, light purple-red host sandstone in the oxidized zone, grey-green sandstone in the oxidized zone and mineralized grey sandstone (ore) in the oxic-anoxic transition zone. Uranium ore bodies occur, as tabular (mostly) and roll-front in shape, within the grey sandstone of unaltered reducing zone near oxic-anoxic transition zone for industrial mineralization and within the grey-green sandstone of oxic-anoxic transition zone for unindustrial mineralization. The gas chromatograms of total saturated hydrocarbons show unimodal distributions and the normal alkanes C17 to C35 with an odd carbon number preference and maxima concentrate around C25–29, which are typical for terrestrial high plant. The organic matter in the unaltered grey host sandstone and the light purple-red host sandstone in the oxidized zone is immature, while the organic matter in the re-reduced grey-green host sandstone and mineralized grey sandstone (ore) has a maturity equivalent to the main stage of petroleum generation (catagenesis). Evidence of hydrocarbon biodegradation associated with uranium mineralization was found. The biodegradation is a bacterial degradation which can be considered as a catalyst for the reduction of uranium. Occurrence of biodegraded migrated organic matter can be considered as a favourable criterion for the settling of uranium mineralization in searching and prospecting for uranium deposit. Finally, a two-stage genetic model of the uranium deposit based on the mixing of three fluids (brine, meteoric water and oil) has been developed. | |||
TO cite this article:Min Maozhong,Wang Jinping,Xie Hongbing. Biodegradation of hydrocarbon in Dongsheng sandstone-hosted uranium deposit,North China[OL].[ 9 February 2010] http://en.paper.edu.cn/en_releasepaper/content/40106 |
3. Crustal Composition of China Continent Constrained from the Heat Flow Data and the Helium Isotope Ratio of Underground Fluid | |||
Wang Yang | |||
Earth Science 10 February 2008 | |||
Show/Hide Abstract | Cite this paper︱Full-text: PDF (0 B) | |||
Abstract:Based on conservation of energy principle and heat flow data in China continent, the upper limit of 1.3 Wm-3 heat production is obtained for continental crust in China. Furthermore, using the data of heat flow and helium isotope ratio of underground fluid, the heat productions of different tectonic units in China continent are estimated in range of 0.58~1.12 Wm-3 with a median of 0.85 Wm-3. Accordingly, the contents of U, Th and K2O in China crust are in ranges of 0.83~1.76g/g, 3.16~6.69g/g, and 1.0~2.12%, respectively. These results indicate that the abundance of radioactive elements in crust of China continent is much higher than that of Archean crust; and this fact implies China’s continental crust is much evolved in chemical composition. Meanwhile, significant lateral variation of crustal composition is also exhibited among different tectonic units in China continent. The crust of eastern China is much enriched in incompatible elements such as U, Th and K than that of western China; and the crust of orogenic belts is more enrichment than that of platform regions. It is also inferred that the crusts of eastern China and orogenic belts are much felsic than those of western China and platform regions, respectively, derived from the positive correlation between the heat production and SiO2 content of bulk crust. This deduction is consistent with the results derived from the crustal seismic velocity data in China. According to the facts that the lower seismic velocity of China than the average value of global crust, and the higher heat production of China continent compared with global crust composition models published by previous studies, it is deduced that the average composition models of global continent crust by Rudnick and Fountain(1995), Rudnick and Gao(2003), Weaver and Tarney(1984), Shaw et al(1986), and Wedepohl(1995) overestimate the abundance of incompatible elements such as U, Th and K of continental crust. | |||
TO cite this article:Wang Yang. Crustal Composition of China Continent Constrained from the Heat Flow Data and the Helium Isotope Ratio of Underground Fluid[J]. |
Select/Unselect all | For Selected Papers |
Saved Papers
Please enter a name for this paper to be shown in your personalized Saved Papers list
|
|
Results per page: |
About Sciencepaper Online | Privacy Policy | Terms & Conditions | Contact Us
© 2003-2012 Sciencepaper Online. unless otherwise stated