权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Rheology of the evolved alkaline magmas of Vesuvius and the Phlegraean Fields: The anomalous effects of chlorine and fluorine

维苏威火山和坎皮莱格瑞地区演化的碱性岩浆的流变学：氯和氟的异常效应

基本信息

批准号：
166279504
负责人：
Professorin Dr. Sharon Webb
金额：
--
依托单位：
Abteilung Experimentelle und Angewandte Mineralogie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/166279504?language=en
关键词：
Rheology evolved alkaline magmas Vesuvius

项目摘要

The effect of Cl and F together, on the rheology and structure of evolved hydrous alkaline melts will be determined via micropenetration viscosity techniques and NMR and Raman spectroscopy. Preliminary studies have shown that chlorine tends to increase the viscosity of dry peralkaline melts and to decrease the viscosity of peraluminous compositions. Chlorine and fluorine together in these melts produces the opposite effect; that is, a slight increase in the viscosity of peraluminous melts and a decrease in viscosity of peralkaline melts. Fluorine alone always decreases silicate melt viscosity. NMR measurements have shown that high field strength cations compete with Al3+ to form bonds with F; while chlorine avoids Al3+ and bonds with both the alkali and alkaline earth cations present in the melt. As explosive volcanic eruptions can be caused by the growth of volatile-filled bubbles in an increasingly high viscosity volatile-poor melt, it is of major importance to understand the interaction of the common volatiles F and Cl and H2O in the melt structure and their effect on magma viscosity. The melt compositions used here are based on the magmas of Vesuvius and the Phlegraean Fields, which have chlorine contents up to 2 mol%, and fluorine contents up to 2 mol%; as well as water content up to 4 wt %.

Cl和F一起对形成的含水碱性熔体的流变学和结构的影响将通过微穿透粘度技术和NMR和拉曼光谱来确定。初步研究表明，氯倾向于增加干过碱性熔体的粘度，并降低过铝质组合物的粘度。氯和氟一起在这些熔体中产生相反的效果，也就是说，在过铝熔体的粘度略有增加和过碱性熔体的粘度下降。单独的氟总是降低硅酸盐熔体粘度。NMR测量表明，高场强阳离子与Al 3+竞争形成与F的键;而氯避免Al 3+和与熔体中存在的碱金属和碱土金属阳离子的键。由于爆炸性火山爆发可能是由在粘度越来越高的贫挥发性熔体中充满挥发性物质的气泡的生长引起的，因此了解熔体结构中常见挥发性物质F和Cl与H2O的相互作用及其对岩浆粘度的影响至关重要。这里使用的熔体组合物基于维苏威火山和Phlegraean Field的岩浆，其具有高达2mol%的氯含量和高达2mol%的氟含量;以及高达4wt%的水含量。