中国大陆新生代典型火山区温室气体释放的规模及其成因

火山活动能够将地球深部的碳输送到大气圈,是地质碳排放和深部碳循环的重要形式.火山作用不仅在喷发期能够释放大量温室气体,而且在休眠期也能释放巨量的温室气体.在全球变暖的背景下,定量化地研究火山活动对大气圈温室气体含量增加的贡献具有至关重要的意义.本文利用密闭气室法等该领域国际先进的测试技术,测量并计算了长白山、腾冲、五大连池及青藏高原南部的羊八井等典型火山区的温室气体释放规模.结果显示,我国大陆新生代典型火山区向大气圈输送的温室气体总通量约为8.13×10⁶t·a^-1,接近10⁷t·a^-1级别,相当于全球火山活动导致的温室气体(主要为CO₂)释放总量的6%左右.太平洋构造域火山区的温室气体在释放通量与总量方面均低于特提斯构造域,并且太平洋构造域火山气体的地壳混染程度较低,显示出大洋俯冲带与大陆俯冲带火山区温室气体释放的成因差异.

Fluxes and genesis of greenhouse gases emissions from typical volcanic fields in China

Deep-seated carbon could be transported from Earth's interior into atmosphere by volcanic activities, which play an important role in geologic carbon degassing. In addition to volcanic eruptions, quiescent volcanoes could also release large amount of magmatic CO₂ into atmosphere. Therefore, quantitative studies on the contribution of volcanic activities to rising of atmospheric CO₂ concentration are critical, especially in the context of global warming. The fluxes of greenhouse gases released from typical volcanic fields (i.e. Changbaishan, Tengchong, Wudalianchi and Yangbajing) in Chinese Mainland are estimated by closed chamber method, gas and water chemistry methods, etc. The total greenhouse gases (referring mainly to CO₂) flux of these typical volcanic fields is 8.13×10⁶ t·a^-1, taking up about 6% of the total CO₂ flux from global volcanoes. In comparison with Pacific tectonic domain, the fluxes of greenhouse gases from volcanic field associated with Thethys tectonic domain are higher. In addition, volcanic gases from Thethys tectonic domain are characterized by higher degree of crustal contamination than those of Pacific tectonic domain, indicating different tectonic settings and mechanisms of magma evolution between oceanic subduction zone and continental subduction zone.