| 内蒙古额济纳盆地硫酸盐沉积物中δ17O异常及其指示意义 |
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| 关键词:sulfate 17O-excess mass-independent fractionation Ejin Basin |
| 基金项目:国家自然科学基金项目(编号: 40572140; 40602030; 41202169) |
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| 17O-excess of Sulfate Deposits in the Ejin Basin of Inner Mongolia and Its Implications |
| Four types of sulfate deposits were sampled in the Ejin Basin, a typical arid area in China, to explore the existence of 17O-excess (defined by Δ17O= δ17O–0.52δ18O≠0) in sulfate and its post-depositional variability in vertical profiles. Both δ17O and δ18O values of collected samples comprising modern windy dust, surface salt crust, dried lake sediments and playa soil were determined simultaneously by the Ag2SO4 pyrolysis method. The analytical error of δ17O, δ18O and Δ17O in this method is 0.5‰, 0.3‰ and 0.1‰, respectively. Some conclusions have been reached: (1) The 17O-excess was found in all the four types of surface deposits in the Ejin Basin (Δ17O=0.2 ~ 1.0‰), which proves that 17O-excess in sulfate can be transferred from the atmosphere to minerals in the earth and is preserved in a specific surface environment as a geological record. (2) The Δ17O values varied from 0‰ to 0.6 ‰ in sulfate and increased from the soil surface downward to about 1m in depth in the vertical soil profile in the Jidegancha playa, which probably resulted from post-depositional leaching and might reveal a unique physical-chemical process during which different sulfate components may be separated in soil profiles under extremely arid climatic conditions. This study has provided new evidence for the argument that 17O-excess of O3 and H2O2 in atmosphere could be transferred into minerals at the earth surface and also supplied effective information to the origin, migration, mixture and post-depositional variation of sulfate. |
| YU Kai,ZHOU Ai-guo,LI Xiao-qian,YU Ting-ting,LIU Yun-de.2014.17O-excess of Sulfate Deposits in the Ejin Basin of Inner Mongolia and Its Implications[J].Acta Geoscientica Sinica,35(3):314-320. |
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