Volcanic emissions of molecular chlorine

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• 作者：Michael Zelenski^a ; ^{ppm61@mail.ru} ; Yuri Taran^b ; ¹ ; ^{taran@geofisica.unam.mx}
• 刊名：Geochimica et Cosmochimica Acta
• 出版年：2012
• 期刊代码：27_00167037
• 类别：ear
• 出版时间：15 June, 2012
• 卷：87
• 期：Complete
• 页码：210-226
• 文件大小：1561 K

摘要

Up to 60 ppmv (180 mg/m³) of Cl₂ together with 40-80 ppmv HCl were measured in gas emissions from the Tolbachik scoria cones, Kamchatka, which are still hot after the 1975-1976 eruption. Other gas components were atmospheric air (94-99 vol%), water vapour (1-6 vol%) and other acid species (HF, CO₂ and H₂SO₄, total less than 0.1 vol%). Two different processes can account for the existence of Cl₂ in the Tolbachik emissions. The catalytic oxidation of volcanic HCl by oxygen is probably the main source of Cl₂. Fine crystals of Fe₂O₃, and oxides and chlorides of other transition metals on the surface of altered basalt can serve as catalysts. The oxidative decomposition of Na, K and Mg chloroferrates formed as a result of basalt acid leaching, can also create high concentrations of molecular chlorine in volcanic gases. The processes described represent a previously unknown case of abiogenic heterogeneous catalysis in nature and examples of gas-rock interactions that affect the composition of volcanic gases.