...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Gas and water geochemistry of geothermal systems in Dominica, Lesser Antilles island arc
【24h】

Gas and water geochemistry of geothermal systems in Dominica, Lesser Antilles island arc

机译：小安的列斯群岛多米尼加的地热系统的天然气和水地球化学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Four of the nine potentially active volcanoes on the island of Dominica in the Lesser Antilles volcanic island arc have associated active volcanic-hydrothermal systems. Between 2000 and 2006 the gas and thermal waters from these systems were investigated to geochemically characterise the fluids, gain insight into the temperature and equilibrium state of the underlying reservoirs, and evaluate the feasibility of monitoring geothermal features as a volcano surveillance tool in Dominica. The geothermal gases are typical of those found in arc-type settings, with N2 excess and low amounts of He and Ar. The dry gas is dominated by CO2 (ranging from 492 to 993 mmol/mol), and has a hydrothermal signature with hydrogen sulphide as the main sulphurous gas. The waters are predominantly acid-sulphate (S04= 100-4200mg/L, pH<4), and likely formed as a result of dilution of acidic gases in near surface oxygenated groundwater. Enrichment in both 818O and 8D with respect to the global meteoric water line (GMWL) confirms that the waters are of primarily meteoric origin, but have been affected by evaporation processes. Quartz geothermometers gave equilibrium temperatures of 83 "C-203 °C. These temperatures contrast with the higher equilibrium temperature ranges (170 "C-350 °C) obtained for the gases using the H2/Ar*-CH4/CO2 gas ratios plot, suggesting that the quartz geothermometers are affected by non-attainment of equilibrium. This may be a result of precipitation of the dissolved silica and/or dilution by relatively cold shallow aquifers of the thermal fluids. Generally, no significant variations in fluid gas chemistry of the hydrothermal systems were observed during the study period, and we propose that there were no changes in the state of volcanic activity in this period. One exception to this occurred in a feature known as the Boiling Lake, which underwent a month-long period of significant compositional, temperature and water level fluctuations ascribed to a drastic decrease of hydrothermal input related to a perturbation in the lake (probably seismically induced). This geochemical study is part of an ongoing monitoring programme of Dominica geothermal systems, aimed at establishing long-term geochemical observations for the purpose of volcano monitoring.
机译：小安的列斯群岛火山岛弧中多米尼加岛上的九个潜在活火山中有四个与活火山热液系统有关。在2000年至2006年之间，对这些系统的天然气和热水进行了研究，以对流体进行地球化学表征，深入了解下伏储层的温度和平衡状态，并评估在多米尼加作为火山监测工具监测地热特征的可行性。地热气体是弧形环境中的典型气体，N2过量且He和Ar含量低。干燥气体以CO2（在492至993 mmol / mol范围内）为主，并具有以硫化氢为主要含硫气体的水热特征。这些水主要是硫酸盐（SO4 = 100-4200mg / L，pH <4），可能是由于酸性气体在近地表含氧地下水中稀释而形成的。 818O和8D相对于全球大气水线（GMWL）的富集证实了这些水主要来自大气，但受到蒸发过程的影响。石英地热仪的平衡温度为83“ C-203°C。这些温度与使用H2 / Ar * -CH4 / CO2气体比率图获得的较高平衡温度范围（170” C-350°C）形成对比，这表明石英地热仪受到未达到平衡状态的影响。这可能是由于溶解的二氧化硅沉淀和/或由相对较冷的浅层导热油稀释造成的。通常，在研究期间未观察到热液系统流体气体化学的显着变化，我们建议在此期间火山活动的状态没有变化。其中一个例外是称为沸腾湖的特征，该沸腾经历了长达一个月的重要组成，温度和水位波动，这归因于与湖中扰动有关的热液输入量急剧下降（可能是地震引起的）。 。这项地球化学研究是多米尼加地热系统正在进行的监测计划的一部分，该计划旨在建立长期的地球化学观测资料，以进行火山监测。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号