摘要：

The paper deals with the difference of climates between Holocene and the Last Interglacial (marine oxygen isotopic stage 5e), which has so far been a contentious point in paleoclimatic study. The Holocene soil and the Eemian paleosol in the famous Achenheim loess section (Alsace, France), the So and S_1 soils in Xifeng(Gansu, China) and Xl'an(Shaanxi, China) loess sections are comparatively studied, based on micromorphological, clay mineralogical and soil chemical analyses. At the three localities, the upper part of the Holocene profile was so strongly disturbed by human activities that it is impossible to identify the soil-forming stages related to the climatic fluctuations of Late Holocene. Only a monophased soil at the lower part was preserved, formed most probably during mid-Holocene. The Eemian soil and the S_1 soil are polycyclic, having recorded two clearly-defined soilforming stages interrupted by a loess deposition stage and the first soil-forming stage shows much hotter condition. This succession of climatic events can be respectively correlated to the deep-sea oxygen isotope stage(OXY) 5e(soil-forming stage), 5d(loess deposition) and 5a—b—c (soil-forming stage). The climatic fluctuations within the OXY 5a—b—c were not recognized in the studied paleosols. In Achenheim, both the Holocene soil and the Last Interglacial (OXY 5e) soil are Orthic Luvisol(FAO system). They are characterized by well developed Bt horizon containing a great amount of yellow-brown, limpid and microlaminated clay coatings with high birefringence, typical of Atlantic broadleaf forest soil(brun lessive). The fact that the Eemian soil is more developed than the Holocene one can be explained as a function of time rather than warmth and/or moisture increases. This is in good agreement with the soils in Mississippi loess (Orthic Luvisol) as well as the marine isotopic record showing similar isotopic values. Corresponding to the OXY 5a—b—c, formed a Luvic Chernozem, indicating a cool steppe or steppe-forest environment. On the contrary, the Holocene S_0 and the OXY 5e soil in S_1 in China are greatly different. In Xifeng, S_0 is a Calcic Chernozem, characterized by spongy microstructure, strong humification and absence of rubification, and formed under cool-temperate and semi-arid steppe environment; whereas the OXY 5e soil is a strongly-rubificated Luvic Kastanozem, comparable to the sub-tropical steppe and steppe-forest soils in North Africa and Mediterranean environments. In Xi'an, So is a Luvic Phaeozem whereas the OXY 5e soil is a strongly rubificated Chromic Luvisol. The OXY 5a—b—c soil can be classified as Calcic Kastanozem in Xifeng and Luvic phaeozem in Xi'an. Our results thus reveal that the climates of Holocene and Last Interglacial in China are greatly different whereas they are similar in West Europe and North America. This suggests that the climatic system since Late Pleistocene in Northern China had been affected by local agents. The uplift of Tibetan Plateau obstructing the south-west monsoon according to earlier studies, could be a possible explanation.

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