Experimental constraints on trace element partitioning between coesite and hydrous silicate melt at 5 GPa and 1500-1750℃  

作　　者：Wei YAN Xi LIU Saijun SUN Weidong SUN Dan WU 

机构地区：[1]Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education of China,Beijing 100871,China [2]School of Earth and Space Sciences,Peking University,Beijing 100871,China [3]Center of Deep Sea Research,Institute of Oceanography,Chinese Academy of Sciences,Qingdao 266071,China [4]Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China

出　　处：《Science China Earth Sciences》2021年第7期1171-1183,共13页中国科学（地球科学英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2016YFC0600408);the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB42000000);the Program of the National Mineral Rock and Fossil Specimens Resource Center from MOST,China。

摘　　要：Trace element partitioning between coesite and hydrous silicate melt has been investigated at 5 GPa and 1500-1750℃.High-P experiments successfully produced large coesite crystals in equilibrium with large silicate melt pools(plus kyanite and corundum crystals in some cases).Scanning electron microscopy and micro-Raman spectroscopy were employed to characterize the phases and the textures.Wavelength-dispersive electron microprobe analyses were performed to quantify conventional major elements,and laser ablation-inductively coupled plasma-mass spectrometry analyses were successfully conducted to quantify trace elements.Eventually,high-P partition coefficients were obtained for 33 elements.In general coesite is a very pure phase.With a few possible exceptions like Sc,Ti,and V,nearly all other trace elements are incompatible in coesite.Moreover,the partitioning behaviors of nearly all trace elements except some 4+cations cannot be readily described by the lattice strain model,presumably implying a minor role for the cation size in the trace-element partitioning.Combining our experimental results with the results in the literature,some T and P effects on the element partitioning behavior have been observed:T seemingly has different effects on different trace elements,but P might negatively correlate with the partition coefficients in all cases.Due to its large modal fraction in some subducted materials such as the continental crustal material,coesite might play an important role in the distributions of some trace elements,Ti for example.

关 键 词：Partition coefficients High-P experiments LA-ICP-MS COESITE Hydrous silicate melt Temperature and pressure dependence 

分 类 号：P57[天文地球—矿物学] P588.3[天文地球—地质学]