Sulfur and Chlorine in Late Cretaceous Deccan Magmas and Eruptive Gas Release
Sulfur and Chlorine in Late Cretaceous Deccan Magmas and Eruptive Gas Release
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DOI：
10.1126/science.1152830
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发表时间：
2008-03
期刊：
影响因子：
56.9
通讯作者：
S. Self;S. Blake;K. Sharma;M. Widdowson;Sarah Sephton
中科院分区：
文献类型：
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作者：
S. Self;S. Blake;K. Sharma;M. Widdowson;Sarah Sephton
67 至 6500 万年前，大量帕霍霍熔岩流喷发，形成印度德干地盾。这些玄武岩喷发对全球大气和同时代白垩纪末大规模灭绝的影响尚不确定。为了评估这次火山活动可能释放的气体，我们测量了晶体内稀有玻璃夹杂物和熔岩内保存的玻璃边的硫和氯浓度。浓度范围从包裹体中约 1400 ppm 的 S 和 900 ppm Cl 到熔岩中的百万分之几百。这些数据表明，德干熔岩喷发最多可释放 0.103 重量％的硫，每立方千米熔岩产生高达 5.4 太克的二氧化硫。更保守的估计是每立方公里喷发的熔岩中含有 0.07 重量％的硫和 0.04 重量％的氯，产生 3.5 太克的 SO2 和 1 太克的 HCl。流量非常大，这些结果意味着大量的 S 和 Cl 气体被释放。即使是过去洪水玄武岩活动期间的个别喷发，对环境的影响也可能很严重。
Large-volume pāhoehoe lava flows erupted 67 to 65 million years ago, forming the Deccan Traps, India. The impact of these flood basalt eruptions on the global atmosphere and the coeval end-Cretaceous mass extinction has been uncertain. To assess the potential gas release from this volcanism, we measured sulfur and chlorine concentrations in rare glass inclusions inside crystals and on glassy selvages preserved within lavas. Concentrations range from ∼1400 parts per million of S and 900 parts per million of Cl in inclusions down to a few hundred parts per million in the lava. These data indicate that eruptions of Deccan lavas could have released at most 0.103 weight % of S, yielding up to 5.4 teragrams of SO2 per cubic kilometer of lava. A more conservative estimate is 0.07 weight % of S and 0.04 weight % of Cl, yielding 3.5 teragrams of SO2 and 1 teragram of HCl for every cubic kilometer of lava erupted. The flows were very large in volume, and these results imply that huge amounts of S and Cl gases were released. The environmental impact from even individual eruptions during past flood basalt activity was probably severe.