New developments in geo-thermometry based on quantitative oxygen analysis using a microprobe to estimate iron oxidation ratio

辉石中铁氧化态的不确定性导致估计地球内部温度的重大不确定性。氧是辉石中唯一的阴离子，并且假设电平衡，阳离子含量的精确测量允许估计铁氧化率。通过考察分析晶体、样品表面、背景识别方法和适当的校正因子，优化了EPMA测氧方法。我们现在能够确定氧气的重量百分比在百分之一以内。

Uncertainty in the oxidation state of iron in pyroxene leads to significant uncertainties in estimating the temperature of the inner earth. Oxygen is the only anion in pyroxene and assuming electrical balance, accurate measurements of cation contents allow the iron oxidation ratio to be estimated. Oxygen measurements using EPMA were optimized by examining the analyzing crystal, sample surface, ways of identifying the background, and appropriate correction factors. We are now able to determine the weight percentage of oxygen to within one percent.