Geochemische und petrologische Untersuchung zur Evaluierung der Hauptelement-Flüsse in Vulkanbogen und die sich daraus ergebenden Konsequenzen für den globalen Stoffkreislauf

地球化学和岩石学调查，以评估火山弧中的主要元素流动及其对全球物质循环的影响

• 批准号: 5397939
• 负责人: Professorin Dr. Susanne M. Straub
• 金额: --
• 依托单位: Lamont-Doherty Earth Observatory
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5397939?language=en
• 关键词: Geochemische; und; petrologische; Untersuchung; zur

The elemental outflux from volcanic arcs is a key variable in the global geochemical cycle, the quantification of which requires the knowledge of the arc growth rate, i.e. the volume added to the arc crust per time increment. The arc growth rate is commonly determined by volumetric methods. However, these methods often yield uncertain numbers, because so much of the material is actually erupted explosively and is either quickly eroded or deposited far from the volcanic site. Analysis of distal tephra fallout permits a more rigorous evaluation of eruption frequency, as well as the chemical composition, which should correlate to first order with crustal growth. Therefore, I propose to establish quantitative links between the composition of arc volcanic rocks and the arc growth rates. The approach builds on the systematic global variations of the arc major elements observed by Plank and Langmuir (1988), that indicate an inverse relationship between the crustal thickness and the degree of subarc mantle melting, and implicate the arc growth rate. To test the Plank and Langmuir (1988) model, I propose carrying out selected case studies in the well-investigated Mexican Volcanic Belt and the Izu Bonin Island arc, using modern microanalytical methods (e.g. LA-ICPMS, ion probe), and in-depth evaluation of published data on arc volcanic rocks. Finally, models will be developed to derive arc growth rates by a combination of volumetric and geochemical methods.

来自火山弧的元素外流是全球地球化学周期中的关键变量，其量化需要了解弧增长速率，即每次增量添加到弧形地壳中的体积。 ARC生长速率通常由体积方法确定。但是，这些方法通常会产生不确定的数字，因为这么多材料实际上是爆炸性爆发的，并且迅速侵蚀或沉积在远离火山地点。远端TEPHRA辐射的分析允许对喷发频率以及化学成分进行更严格的评估，这应该与地壳生长相关。因此，我建议在电弧火山岩的组成与电弧增长率之间建立定量联系。该方法建立在Plank and Langmuir（1988）观察到的ARC主要要素的系统全球变化上，该元素表明地壳厚度与超质量地幔融化程度之间存在反向关系，并暗示了ARC生长速率。为了测试Plank and Langmuir（1988）模型，我建议使用现代的微分析方法（例如LA-ICPMS，ION探针）和对ARC Volcanic Rocks的出版数据评估，使用现代的微分析方法（例如LA-ICPMS，ION探针），在墨西哥火山带和Izu Bonin Island Arc中进行选定的案例研究。最后，将开发模型来通过体积和地球化学方法的组合来得出弧的增长率。