中文摘要：

海洋有孔虫的硼同位素能够反映海水酸碱度值的变化，为研究大气CO2浓度在长时间尺度上的变化提供了一种新的手段，甚至可能超出冰芯所能企及的范围。天然样品中硼同位素的测定方法最为常用的是热电离质谱法，分为正热电离质谱法与负热电离质谱法。目前海洋有孔虫硼同位素分析主要应用负热电离质谱法，该方法最大的优点是所需要的样品量比较小（〈1ngB），实验精度却相对比较高（0．6‰-2．0‰；2s．d．）。近年来，基于常规负热电离质谱法发展的全蒸发负热电离质谱法通过分析完所有样品而有效降低分析过程中所发生的分馏效应所带来的影响，并使样品的信号最大化，该方法精度能够达到0．7‰（2s．d．）。本文详细介绍了常规负热电离质谱法和全蒸发负热电离质谱法的各个分析步骤，包括样品前处理、涂样、质谱分析、同质异位素于扰以及实验分析精度等方面。随着实验分析技术的进展，海洋有孔虫硼同位素已被用来重建长时间尺度（百万年和千万年）和短时间尺度（冰期-间冰期）的大气CO2浓度变化。现有的研究证实利用海洋浮游有孔虫硼同位素重建的大气CO2浓度变化与Vostok冰芯记录的大气CO2浓度变化吻合地很好。

英文摘要：

Boron isotopes of marine planktonic foraminifers can reflect seawater pH changes,thus provide a new tool for the reconstruction of atmospheric pCO2 on long-term timeseale, even beyond the reach of Vostok ice cores. In natural samples,boron isotopes are normally measured by thermal ionization mass spectrometry （TIMS） , including negative thermal ionization mass spectrometry（NTIMS） and positive thermal ionization mass spetrometry （PTIMS）. NTIMS is often used for marine foraminiferal boron isotope analyses, which has a precision up to 0.6‰ -2.0‰ （2s. d. ）with relatively small sample amount （less than lng B）. Recently total evaporation NTIMS has been developed to measure boron isotopes in marine formanifers precisely and accurately（0.7‰; 2s. d. ）whereby the effect of instrumental mass fractionation is minimized and sample signal maximized by analysing samples to exhaustion. This paper introduces in details both regular NTIMS and total evaporation NTIMS including sample preparation, loading, instrumental measurements, isotope interference, and analytical accuracy. With the progresses of analytical measurements, boron isotopes in marine foraminifers have been used to reconstruct the atmospheric pCO2 changes on both long-term（million-year）and short-term（glacial-interglacial）timescales. The available results found that atmospheric pCO2 variations reconstructed according to boron isotopes of marine foraminifers agree well with the records from Vostok ice cores.