作者：白  滨，王  旭 

　　摘要：探讨古环境和古气候变化与哺乳动物演化之间的关系是目前古生物学研究领域中的一个热点，而哺乳动物化石牙齿釉质的碳、氧同位素分析是恢复古环境和古气候的一个重要手段。以往的哺乳动物化石牙齿釉质稳定同位素分析多集中在大哺乳动物化石，这主要是受到技术手段的限制，所需的样品量较大所决定的。但最近几年随着激光和离子显微探针技术的应用，对小哺乳动物化石(如啮齿类和兔形类)的牙齿釉质碳、氧同位素的分析和应用日趋成熟和广泛。除了传统的化学处理方法之外，对小哺乳动物化石牙齿釉质碳、氧同位素的分析还有以下三种方法：1) 激光剥蚀气相色谱/同位素比值质谱分析；2) 直接激光氟化技术；3) 离子显微探针技术(SHRIMP II)。这些技术需要的样品量少，对标本的破损小，准确度和精密度高，所以在小哺乳动物化石和一些珍贵标本(如古人类化石)的稳定同位素分析中起到了重要作用。相对于大哺乳动物化石，小哺乳动物化石数量多、演化速度快，更能反映多个层位长时间序列的古环境和气候变化；而且小哺乳动物通常没有长距离迁徙的行为，栖息地局限，所以更能准确反映化石埋藏地点的古环境和气候状况。 

　　关键词：小哺乳动物化石，牙齿釉质，碳、氧同位素，激光和离子显微探针技术 

　　卷期：51卷 03期 

A review of methods in carbon and oxygen isotopic analyses of tooth enamel from small fossil mammals

BAI Bin, WANG Xu

Abstract  Measurements of carbon and oxygen isotopes in mammalian tooth enamel have been widely used for the paleoenvironmental and paleoclimatic reconstructions. However, previous studies mainly focused on relatively large mammals owing to sample size and technique constraints. As the result of recent developments in laser and ion microprobe techniques, stable isotopic analyses can be also applied to small mammal teeth (e.g. rodents and lagomorphs). Based on the previous reports, three techniques with high accuracy and precision but requiring much smaller quantity of samples are reviewed and compared in the present paper. These techniques include: 1) laser ablation Gas Chromatography/Isotope Ratio Mass Spectrometry (GC/IRMS); 2) Direct Laser Fluorination (DLF); 3) Sensitive High Resolution Ion MicroProbe (SHRIMP II). Compared with large fossil mammals, small ones are characterized by much higher abundance, more rapid evolution and more restricted habitats. Thus, small fossil mammals can be widely used for long-term local paleoenvironment and paleoclimate studies with high-resolution in the Cenozoic era.

Key words  small fossil mammal, tooth enamel, carbon and oxygen isotopes, laser and ion microprobe technique