Study on soil micro-seepage gas flux in the high temperature geothermal area: An Example from the Yangbajing geothermal field, South Tibet
文献类型：期刊论文
| 作者 | Zhang LiHong; Guo ZhengFu; Zhang MaoLiang; Cheng ZhiHui |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2014-12-01 |
| 卷号 | 30期号:12页码:3612-3626 |
| 关键词 | Soil micro-seepage CO2 flux Closed chamber method Yangbajing geothermal field Tibetan Plateau |
| ISSN号 | 1000-0569 |
| 文献子类 | Article |
| 英文摘要 | Soil micro-seepage associated with high temperature geothermal systems has long been regarded as one of the most important forms of deep earth degassing, especially for the CO2. Estimation of soil micro-seepage CO2 flux for geothermal systems could contribute to understanding the role of geothermal CO2 in global carbon cycle. The soil micro-seepage CO2 fluxes of geothermal areas have been well investigated in abroad, while few similar studies are available in China at present. In this paper, the closed chamber method for measurement and calculation of soil micro-seepage CO2 flux is introduced and applied in Yangbajing geothermal field, South Tibet. The study area is divided into two parts according to the intensity of geothermal activity, i.e., A area with weak soil micro-seepage CO2 emissions and B area with intense soil micro-seepage CO2 emissions. The results show that, the soil micro-seepage CO2 flux of A area and B area is 6.7g . m(-2) . day and 98.5g . m(-2) . day(-1), respectively. The total soil micro-seepage CO2 flux of Yangbajing geothermal field is up to 8.6 x 10(4)t . a(-1), which is comparable to the total CO2 emission( 1 x 10(5)t . a(-1)) of the Vulcano volcanic field, Italy. The soil micro-seepage gas flux may be mainly controlled by NS trend rift and magmatism around the studied area Yangbajing geothermal field is one of the most intense degassing areas in southern Tibet. Systematic studies on soil micro-seepage CO2 fluxes of geothermal field in southern Tibet would be significant to evalule the contribution of the geological CO2 to the global carbon cycle. Furthermore, the origin of the greenhouse gas from Yangbajing geothermal field is still poorly understood at present. Gas samples were collected for analyses of gas compositions, helium and carbon isotopic compositions, in order to unravel the genesis of soil micro-seepage CO2 emission. The geochemical signatures of gas samples show that, helium isotope ratios varies between 0.1R(A) and 0.138R(A) (where R-A = He-3/He-4 in air), significantly lower than that of mantle derived volatiles but higher than the crustal values; carbon isotope values (delta C-13) fall between -11.33 parts per thousand and -6.79 parts per thousand (vs. PDB), indicating contamination by crustal organic sediments. The observed helium isotopic composition of the gas could be explained by the mixing of components from air (1R(A)), crustal sediments (0.03R(A)) and little mantle volatiles(1% similar to 3%). The carbon isotopic compositions indicate contributions from granite gneiss that are heated by the crustal magma, as well as little contribution from mantle component (3.6%). In combination with geophysical studies, we suggest that, the geothermal gas might originate from the intrusive magmas containing little mantle-derived components in the Tibetan crust, which might be related with the thickening continental crust of Tibet since the Indo-Asia collision at 55Ma. |
| WOS关键词 | INDIA INTRACONTINENTAL SUBDUCTION ; LHASA BLOCK ; CO2 FLUX ; DIFFUSE EMISSION ; VOLCANIC-ROCKS ; CARBON-DIOXIDE ; POSTCOLLISIONAL MAGMATISM ; ISOTOPIC COMPOSITIONS ; HYDROTHERMAL AREA ; NORTHERN TAIWAN |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000347270400011 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/86088]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Zhang LiHong |
| 作者单位 | Chinese Acad Sci, Inst Geol & Geophys, Key Lab Cenozo Geol & Environm, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zhang LiHong,Guo ZhengFu,Zhang MaoLiang,et al. Study on soil micro-seepage gas flux in the high temperature geothermal area: An Example from the Yangbajing geothermal field, South Tibet[J]. ACTA PETROLOGICA SINICA,2014,30(12):3612-3626. |
| APA | Zhang LiHong,Guo ZhengFu,Zhang MaoLiang,&Cheng ZhiHui.(2014).Study on soil micro-seepage gas flux in the high temperature geothermal area: An Example from the Yangbajing geothermal field, South Tibet.ACTA PETROLOGICA SINICA,30(12),3612-3626. |
| MLA | Zhang LiHong,et al."Study on soil micro-seepage gas flux in the high temperature geothermal area: An Example from the Yangbajing geothermal field, South Tibet".ACTA PETROLOGICA SINICA 30.12(2014):3612-3626. |
入库方式： OAI收割
来源：地质与地球物理研究所
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