Geochemistry of volcanics and fluid-rock interactions in hydrothermal systems in the Manus Basin

马努斯盆地热液系统中火山岩和流体-岩石相互作用的地球化学

• 批准号: 61068878
• 负责人: Professor Dr. Wolfgang Bach
• 金额: --
• 依托单位: Fachgebiet Petrologie der Ozeankruste
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/61068878?language=en
• 关键词: Geochemistry; volcanics; fluid; rock; interactions

The eastern Manus Basin (EMB) is one of world’s most plate-tectonically active and geochemically diverse regions. Many volcanic centers in the Manus Basin host hydrothermal systems that are affected by magma degassing to variable extent. The geochemical diversity of these systems provides an unparalleled opportunity to examine magma degassing and its consequences for mass transport in hydrothermal systems. During a recent RV Melville cruise volcanic rocks as well as hydrothermal fluids and sulfides were collected in different areas of the EMB. The rocks cover a range from pillow basalt to highly vesicular felsic lava, some of which are highly porphyritic. Rock alteration in the immediate vicinity of the fluid discharge area is also strongly variable, ranging from argillaceous to acid-sulfate alteration. These samples will allow the assessment of magmatic differentiation in relation to input of magmatic components into the hydrothermal system and consequences for fluid-rock interactions and metal transport. Geochemical data of fresh and altered rocks from hydrothermally active areas will be combined with chemical analyses of vent fluids in model calculations aimed at explaining (1) the phase assemblages observed and (2) the vent fluid chemistry. We will use reaction path models to simulate fluid-rock interactions with variable input of magmatic components. The results will be combined with data from NSF-funded companion projects in order to obtain a comprehensive understanding of mass transfers in the Manus Basin magmatic-hydrothermal systems.

马努斯盆地东部(EMB)是世界上板块构造最活跃、地球化学最多样的地区之一。马努斯盆地的许多火山中心都有热液系统，这些系统受到岩浆脱气的不同程度的影响。这些系统的地球化学多样性为研究岩浆脱气及其对热液系统中物质传输的影响提供了一个无与伦比的机会。在最近的一次房车巡航中，梅尔维尔巡航在环境监测局的不同区域收集了火山岩以及热液流体和硫化物。岩石覆盖范围从枕状玄武岩到高度孔洞的长英质熔岩，其中一些是高度斑状的。流体流出区附近的岩石蚀变也很多变，从泥质到酸性硫酸盐蚀变不等。这些样品将能够评估与岩浆成分进入热液系统有关的岩浆分异以及流体-岩石相互作用和金属运移的后果。来自热液活动区的新鲜岩石和蚀变岩石的地球化学数据将在模型计算中与喷口流体的化学分析相结合，旨在解释(1)观察到的相组合和(2)喷口流体化学。我们将使用反应路径模型来模拟具有可变岩浆组分输入的流体-岩石相互作用。结果将与国家科学基金会资助的配套项目的数据相结合，以便全面了解马努斯盆地岩浆-热液系统中的质量转移。