The weathering and element fluxes from active volcanoes to the oceans: a Montserrat case study
The weathering and element fluxes from active volcanoes to the oceans: a Montserrat case study
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DOI：
10.1007/s00445-010-0397-0
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发表时间：
2011-04
影响因子：
3.5
通讯作者：
Morgan T. Jones;Morgan T. Jones;D. Hembury;M. Palmer;Bill Tonge;W. Darling;S. Loughlin
中科院分区：
文献类型：
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作者：
Morgan T. Jones;Morgan T. Jones;D. Hembury;M. Palmer;Bill Tonge;W. Darling;S. Loughlin
1995年至今，蒙特塞拉特（小安的列斯群岛）的苏弗里耶尔火山爆发，使该岛部分地区覆盖了新的火山沉积物。由于新鲜火山碎屑物质的高地形和径流以及高化学和物理风化率，蒙特塞拉特等火山岛是全球风化通量的重要组成部分。我们研究了最近的火山活动对地球化学的影响，预先存在的水文系统，并表明，新鲜的火山物质的初始化学风化产率是高于小安的列斯群岛弧内的老存款。硅酸盐风化可能消耗了苏弗里耶尔火山早期二氧化碳排放量的1.3%。相比之下，死火山大厦，如蒙特塞拉特中部的中心山是大气中二氧化碳的净汇，因为相对于大陆硅酸盐岩石风化，风化率持续升高。因此，弧火山作为大气CO2的源或汇的作用关键取决于它在其生命周期中所处的阶段，随着喷发活动的减弱，它从净源变为净汇。虽然爆发的开始对苏弗里耶尔山中心周围的地下水产生了深远的影响，但北部5公里处的中心山泉水的地球化学似乎未受最近火山活动的影响。这对该岛居民饮用水供应是否有潜在的污染风险产生了影响。
The eruptions of the Soufrière Hills volcano on Montserrat (Lesser Antilles) from 1995 to present have draped parts of the island in fresh volcaniclastic deposits. Volcanic islands such as Montserrat are an important component of global weathering fluxes, due to high relief and runoff and high chemical and physical weathering rates of fresh volcaniclastic material. We examine the impact of the recent volcanism on the geochemistry of pre-existing hydrological systems and demonstrate that the initial chemical weathering yield of fresh volcanic material is higher than that from older deposits within the Lesser Antilles arc. The silicate weathering may have consumed 1.3% of the early CO2emissions from the Soufrière Hills volcano. In contrast, extinct volcanic edifices such as the Centre Hills in central Montserrat are a net sink for atmospheric CO2due to continued elevated weathering rates relative to continental silicate rock weathering. The role of an arc volcano as a source or sink for atmospheric CO2is therefore critically dependent on the stage it occupies in its life cycle, changing from a net source to a net sink as the eruptive activity wanes. While the onset of the eruption has had a profound effect on the groundwater around the Soufrière Hills center, the geochemistry of springs in the Centre Hills 5 km to the north appear unaffected by the recent volcanism. This has implications for the potential risk, or lack thereof, of contamination of potable water supplies for the island’s inhabitants.