A New Technique for Calculating Oxygen Fugacity of a Magma Using Uraninite in Granites

• 作者: GUO Jian LI Ziying HUANG Zhizhang LI Xiuzhen ZHANG Yuyan FAN Chou
• 来源期刊: 地质学报（英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: RESEARCH ADVANCES
• 页码范围: 708-709
• 页数: 2页
• 语种: 英文

摘要

Objective Oxygen fugacity is an important physicochemical parameter of magmas in addition to temperature,pressure and elemental concentrations,representing a major research topic in natural and experimental petrology.Aside from oxygen probe work,where a direct measurement is made using an oxygen sensor to detect the oxygen content in the fluid and molten metal,previous studies,apart have more commonly used variable valency elements in rocks and minerals to indirectly estimate the oxygen fugacity of the magma.Uraninite is the main U-bearing accessory mineral in granites.Uranium in uraninite occurs mainly as U4+or U6+,depending on the oxygen fugacity of the magma.Li(2015)utilized an X-ray photoelectron spectroscopic(XPS)in-situ micro-analytical technique to determine the elemental valency of natural U-bearing minerals.In this study,we used XPS to directly measure the uraninite U6+and U4+contents in granites,estimated the magma oxygen fugacity,then discussed the reliability of this new technique.