...
  • 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 >Geothermal surface alteration of basalts, Krysuvik Iceland—Alteration mineralogy,water chemistry and the effects of acid supply on the alteration process
【24h】

Geothermal surface alteration of basalts, Krysuvik Iceland—Alteration mineralogy,water chemistry and the effects of acid supply on the alteration process

机译：冰岛克雷苏维克玄武岩的地热表面蚀变—蚀变矿物学，水化学和酸供应对蚀变过程的影响

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

The geothermal surface alteration of basalts and associated water chemistry at Krysuvik, SW Iceland were studied. The geothermal area was characterised with zones of intensive surface alteration, steam vents, mud pots and hot springs. The steam-heated geothermal surface waters had pH values between 1.69 and 7.67 and total dissolved solid (TDS) concentrations between 154 and 6660 ppm, with Cl and S04 concentration decreasing and increasing with decreasing pH, respectively. Alteration mineral assemblages observed were strongly associated with the surface intensity. In areas of most intensive activity the basaltic rocks were altered to amorphous silica, anatase and pyrite with a crust of native sulphur at the surface. With decreased activity, kaolinite became important, as well as iron oxyhydroxides and oxides. On the flanks of the area montmorillonite was the predominant alteration product. Based on these observations the surface geothermal activity was divided into three groups: (1) high activity areas with active steam vents and mud pots and intensive acid leaching, (2) medium activity areas where the ground is hot, steam vents and mud pots are uncommon and the surface alteration is less intensive and (3) low activity areas on the margins of the surface geothermal activity. The primary factors influencing the steam-heated acid sulphate alteration of basalts included the redox state (oxidation front), supply of acids and pH, and the extent of reaction. The formation of iron- and sulphur-containing minerals and the respective elemental mobility depended on the redox conditions with pyrite formation under reduced conditions and goethite and/or hematite under oxidised conditions. At low pH, Ca, Mg, K and Na were mobile and leached out, whereas Fe, Ti and Al and to a large degree Si were retained in the alteration product. At higher pH values >5 the mobility of Ca, Mg, K and Na was reduced due to the formation of clays.
机译：研究了冰岛西南部Krysuvik玄武岩的地热表面变化及相关的水化学。地热区的特征是强烈的地表变化区，蒸汽喷口，泥锅和温泉区。蒸汽加热的地热地表水的pH值在1.69至7.67之间，总溶解固体（TDS）浓度在154至6660 ppm之间，其中Cl和SO4的浓度分别随pH的降低而降低和升高。观察到的蚀变矿物组合与表面强度密切相关。在活动最激烈的地区，玄武岩变为无定形硅石，锐钛矿和黄铁矿，表面有天然硫壳。随着活性的降低，高岭石以及羟基氧化铁和氧化物变得重要。在该地区的侧面，蒙脱石是主要的蚀变产物。根据这些观察结果，地表地热活动分为三类：（1）具有活跃的蒸汽喷口和泥浆池以及强烈的酸浸的高活性区域；（2）地面较热，蒸汽喷口和泥浆池较热的中等活动区域罕见，且地表变化强度较小；（3）地表地热活动边缘的低活动区。影响玄武岩蒸汽加热酸性硫酸盐蚀变的主要因素包括氧化还原状态（氧化前沿），酸的供应和pH值以及反应程度。含铁和硫的矿物的形成以及相应的元素迁移率取决于氧化还原条件，还原条件下形成黄铁矿，氧化条件下形成针铁矿和/或赤铁矿。在低pH值下，Ca，Mg，K和Na可以移动并浸出，而Fe，Ti和Al以及大部分Si保留在蚀变产物中。在较高的pH值> 5时，由于形成了粘土，因此Ca，Mg，K和Na的迁移率降低。

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