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通过分析华北晚中新世保德期三个经典地点的羚羊牙齿釉质之稳定碳同位素,结合相同地点的单纯食叶者(鹿科)与食草者(三趾马)的数据,推断其食性取向。结果显示这些晚中新世生态系统中C_3植物占据主导地位,但也含有一小部分的C_4植物(可能小于30%)。高冠羚羊(Gazella dorcadoides类型)取食约20%的C_4植物,而中冠羚羊(G．paotehensis类型)与低冠羚羊(G．gaudryi类型)为纯C_3植物消费者。鹿科动物单纯取食C_3植物,而三趾马与G．dorcadoides类型的羚羊取食C_4植物的比例在统计上难以区分。碳同位素数据与G．gaud- ryi类型的食叶性以及G．dorcadoides类型以草食为主的观点相一致。参照这些类群的地理分布,当前的数据支持晚中新世黄土高原东南部处于相对于西北部更为封闭环境的观点。这种环境梯度的分布方向与模式可能是该地区东亚季风体系的早期信号。
Based on the analysis of the stable carbon isotopes of the antelopes enamel in the three classic sites of the Paleozoic in the Paleozoic Eoceces in North China and the data of simple clover (Deer Branch) and herbivore . The results show that C_3 plants predominate in these late Miocene ecosystems, but also contain a small fraction of C_4 plants (which may be less than 30%). The Gazella dorcadoides species consume about 20% of the C_4 plants, while the G. candeensis type and the G.gaudryi type are pure C_3 plant consumers. Deer family animals fed C_3 plants, and three-toed horses and G. The proportion of dorcadoides-type antelope fed on C_4 plants is statistically indistinguishable. Carbon isotope data and G. gaud-ryi type of leafy and G. The dorcadoides type is the same as the herbivore. With reference to the geographic distribution of these groups, current data support the view that the southeastern loess plateau of the Late Miocene is in a more closed environment relative to the northwestern part of the country. The distribution direction and pattern of this kind of environmental gradient may be the early signals of the East Asian monsoon system in this area.