Trace element features of slab-fluids under high-pressure and high-temperature conditions using synchrotron x-ray fluorescence analysis

使用微聚焦同步x射线束，在不同浓度（Na， K）Cl下获得了水溶液和单倍花岗岩或翡翠熔体的原位x射线荧光光谱。计算了Pb、Rb和sr在水流体和熔体之间的分配系数，分配系数与压力呈正相关，分配系数与盐度呈正相关。与含25wt .% (Na， K)Cl的盐水相比，当无Cl的水溶液与熔体共存时，它们只能溶解大离子亲石元素量的十分之一（Pb, Rb）至五分之一（Sr）。在13 ~ 25 wt.% (Na， K)Cl的体系中，Rb和Pb的分配系数大于1，表明这种高盐流体具有有效传递Pb和Rb的能力。

Using a micro-focused synchrotron x-ray beam, in-situ x-ray fluorescence spectra are obtained from aqueous fluids and haplogranite or jadeite melts under varied concentrations of (Na, K)Cl. Partition coefficients between the aqueous fluids and melts are calculated for Pb, Rb, and Sr. There is a positive correlation between the partition coefficients and pressure, as well as the partition coefficients and salinity. As compared to the saline fluids with 25 wt.% (Na, K)Cl, the Cl-free aqueous fluids can only dissolve one tenth (Pb, Rb) to one fifth (Sr) of the amount of large ion lithophile elements when they coexist with the melts. In the systems with 13-25 wt.% (Na, K)Cl, the partition coefficients of Rb and Pb are greater than unity, indicating the capacity of such highly saline fluids to effectively transfer Pb and Rb.