DataSheet1_Gas Emissions From the Western Aleutians Volcanic Arc.docx

The Aleutian Arc is remote and highly active volcanically. Its 4,000 km extent from mainland Alaska to Russia’s Kamchatka peninsula hosts over 140 volcanic centers of which about 50 have erupted in historic times. We present data of volcanic gas samples and gas emission measurements obtained during an expedition to the western-most segment of the arc in September 2015 in order to extend the sparse knowledge on volatile emissions from this remote but volcanically active region. Some of the volcanoes investigated here have not been sampled for gases before this writing. Our data show that all volcanoes host high-temperature magmatic-hydrothermal systems and have gas discharges typical of volcanoes in oceanic arcs. Based on helium isotopes, the western Aleutian Arc segment has minimal volatile contributions from the overriding crust. Volcanic CO2 fluxes from this arc segment are small, compared to the emissions from volcanoes on the Alaska Peninsula and mainland Alaska. The comparatively low CO2 emissions may be related to the lower sediment flux delivered to the trench in this part of the arc.

阿留申弧（Aleutian Arc）地处偏远且火山活动高度活跃。该弧带从阿拉斯加本土延伸至俄罗斯堪察加半岛，全长4000公里，境内分布140余处火山中心，其中约50座在历史时期曾发生喷发。本数据集收录了2015年9月对该弧最西段开展考察期间采集的火山气体样本与气体排放测量数据，旨在补充这一偏远但火山活动频繁区域的挥发物排放相关研究空白——当前该领域的已有知识仍较为匮乏。本次研究涉及的部分火山，在本文撰写前从未有过气体采样记录。数据分析结果显示，所有受访火山均具备高温岩浆热液系统，且气体排放特征符合大洋弧火山的典型表现。基于氦同位素分析，阿留申弧西段的挥发物来源几乎未受上覆地壳的影响。与阿拉斯加半岛及阿拉斯加本土的火山排放水平相比，该弧段的火山二氧化碳（CO₂）通量相对较低。这种偏低的二氧化碳排放特征，可能与该弧段区域向海沟输送的沉积物通量更低存在关联。