Abstract: The tooth enamel of mammalian fossil is able to be efficiently resistant to diagenesis and retains the original carbon and oxygen isotopic composition. On the basis of the analyses to the isotopic composition of herbivorous mammalian tooth enamel, the paleoclimates when these mammals. lived can be reconstructed. The carbon isotopic composition of structural carbonate in tooth enamel responds to that of dietary plants. According to this principle, the proportions of C3 and C4 plants in the terrestrial ecosystem can be estimated, which were controlled mainly by C02 atmospheric levels, moisture stress and irradiance as well as related to different latitudinal or climatic zones. The oxygen isotopic composition of biogenic phosphate in tooth enamel responds to that of ingested water from precipitation whose oxygen isotopic composition responds to temperature variations. As a result, there is an outstanding correlation between oxygen isotopic composition of tooth enamel and temperature. In the light of this pattern, the annual average temperature in the geological periods can be calculated and the climatic variation curve of cold and warn-I in the geological periods can be made.

摘要： 哺乳动物化石牙齿釉质能有效地抵抗成岩作用的影响，并保存原始的碳、氧稳定同位素组成信息。通过对食草类哺乳动物化石牙齿釉质同位素组成的分析可以重建这些动物生存时代的古气候。釉质碳酸盐的碳同位素组成响应于取食植物的碳同位素组成，藉此可以恢复陆地生态系统中C3和C4植物的分布比例，这个比例主要受控于大气的CO2水平、气压和光照等因素，与不同的纬度带和气候带有关;釉质磷酸盐的氧同位素组成响应于饮用水的氧同位素组成，饮用水来源于大气降水，其氧同位素组成响应于温度变化，所以釉质的氧同位素组成与气温之间有显著的线性相关，