Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8914271 | Journal of Asian Earth Sciences | 2017 | 7 Pages |
Abstract
There are many mud volcanoes in the southern margin of the Junggar Basin, northwest China, of which the Dushanzi area is the most typical and active one, emitting large amount of greenhouse gases associated with water and mud. The emitted gas is dominated by methane (average 90.1%), together with other gases, such as ethane (4.84-5.46%), propane (0.06-0.90%), CO2 (0.67-1.0%), and N2 (2.8-3.3%). The carbon (δ13C1) and hydrogen (δD) isotopic ratios of methane are in the ranges of â40.6â° to â45.0â° and â221â° to â249â°, respectively, whereas carbon isotope ratios of ethane (δ13C2) are â25.2â° to â27.6â°. Based on δ13C values, the released gas is characterized as a thermogenic coal-type and possibly originated from the middle-low Jurassic coal-bearing sequences according to the gas-source correlation and regional geology. Helium isotopes show a crustal source. The methane flux of Dushanzi mud volcanoes from both macro-seepage (craters/vents) and micro-seepage (ground soil exhalation) ranged over the orders of magnitude, from 0.4-2.7 kg dâ1 and 4950 mg mâ2 dâ1 on average, respectively. Positive CH4 fluxes from dry soil were widespread throughout the investigated areas. The total CH4 emission from Dushanzi mud volcanoes is estimated to be at least 22.6 tons aâ1, of which about 89% is from micro-seepage surrounding the mud volcano vents.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Guodong Zheng, Xiangxian Ma, Zhengfu Guo, David R. Hilton, Wang Xu, Shouyun Liang, Qiaohui Fan, Wenxing Chen,