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利用气相色谱-质谱联用仪（GC/MS）从兰州九洲台全新世古土壤（S0）、马兰黄土（L1）和离石黄土顶部的S1等黄土-古土壤系列中检测出种类众多的异地源和原地源分子化石,这两类分子化石的共存与黄土的风成成因有关,而只有其中的原地分子才对研究区古植被的恢复有意义.在引进了一种评估异地源贡献的方法以后,计算出来的原地源正构烷烃分布反映了研究区从末次间冰期以来发育了草原植被的景观,其中全新世最暖期可能还有一定的木本植物,末次冰期可能出现荒漠（草原）植被.这些研究结果与新近报道的植物硅酸体资料吻合,为末次间冰期以来黄土高原塬面上有关古植被景观的争议提供了新的分子化石方面的证据.黄土地层的工作也揭示了在分子地层学的工作中,要考虑异源分子化石存在的可能性.
A large number of remote sites were detected by gas chromatography-mass spectrometry (GC / MS) from series of Holocene Paleosols (S0), Malan Loess (Ll) and top loess-paleosol Source and original source fossils, the coexistence of these two types of molecular fossils is related to the aeolian genesis of loess, and only the in situ elements of them are meaningful to the restoration of ancient vegetation in the study area. , The calculated distribution of n-alkanes shows the landscape of grassland vegetation in the study area since the last interglacial period, in which there may be some woody plants in the warmest in the Holocene, and the desert may appear in the last ice age (Grassland) vegetation.These findings are in good agreement with the recently reported phytolith data, providing new molecular fossil evidence for the debate over the landscape of ancient vegetation in the plateau over the Loess Plateau since the end of the interglacial period It reveals that in the work of molecular stratigraphy, we should consider the possibility of existence of heterologous molecular fossils.