Determination of Volcanic Flux Rates and Application to Understanding Regional Geochemical Trends and Element Mass Balances in Central America

EAR-0203388迈克尔·J·卡尔关于俯冲过程性质的几个重要问题需要从现有的定性俯冲信号转换，如Ba/La和10Be/9Be，到定量通量，如以Gm/单位弧长/Yr为单位的Ba通量。这是通过使用40Ar/39Ar测年技术来测量中美洲几个大型火山中心较老单位的年龄来实现的。这些新数据，加上以前确定的体积测量，可以确定不同弧段的平均火山通量速率。将火山通量速率与区域地球化学数据结合起来，可以对元素通量进行估计。根据这些综合数据，正在解决几个主要问题，包括中美洲俯冲信号沿走向变化的物理原因，通过中美洲弧旋回的元素的质量平衡，以及通过俯冲向地幔深处输送的不相容元素的数量。

EAR-0203388 Michael J. Carr Several important questions about the nature of the subduction process require a transition from existing qualitative subduction signals, such as Ba/La and 10Be/9Be, to quantitative fluxes such as Ba flux in gm/unit arc length/yr. This is accomplished by employing 40Ar/39Ar dating techniques to measure the ages of the older units in several large Central American volcanic centers. These new data, along with previously determined volume measurements, enable the determination of average volcanic flux rates for different segments of the arc. Integrating volcanic flux rates with regional geochemical data allows an estimate of element fluxes to be made. From these integrated data several major problems are being addressed, including the physical cause of along-strike variations in subduction signal in Central America, the mass balance of elements cycling through the Central American arc, and the quantity of incompatible elements that are delivered to the deep mantle through subduction.