Collaborative Research: Modeling the chemistry, origin, and evolution of subduction zone fluids rising beneath the Mariana forearc

合作研究：模拟马里亚纳弧前上升的俯冲带流体的化学、起源和演化

• 批准号: 0646630
• 负责人: Michael Mottl
• 金额: $ 15.94万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0646630&HistoricalAwards=false
• 关键词: Collaborative; Research; Modeling; chemistry; origin

The investigators will use the chemistry of fluids rising through mud volcanoes on the Mariana forearc to infer pressure-temperature and chemical conditions at the top of the subducting slab, to constrain processes in the shallow subduction zone, and to estimate mass fluxes through the Mariana forearc resulting from this process. They will do this by 1) thermodynamic modeling of water-rock interaction under a range of blueschist-facies conditions beneath the forearc, for both sediment and basalt, using the observed spring compositions and recovered metamorphic rocks as constraints; 2) modeling of the progressive reaction of these metamorphic fluids with harzburgite during their ascent; and 3) comparing the composition of subducting oceanic basalt and sediment with fluxes represented by the springs and the ascending serpentinite.

研究人员将利用通过马里亚纳弧前泥火山上升的流体的化学来推断俯冲板顶部的压力-温度和化学条件，限制浅俯冲区的过程，并估计这个过程导致的通过马里亚纳弧前的质量通量。他们将通过以下方式做到这一点：1)使用观察到的泉水成分和恢复的变质岩作为约束，对弧前以下一系列蓝片岩相条件下的沉积物和玄武岩进行水-岩相互作用的热力学模拟；2)模拟这些变质流体在上升过程中与方辉橄榄岩的渐进反应；以及3)比较俯冲的大洋玄武岩和沉积物的组成与泉水和上升的蛇纹岩所代表的通量。