• 责任者：Zeng Lin (Laboratory of Earth Surface Process and Environment ; School of Geographic and Oceanographic Sciences ; Nanjing University ; Nanjing 210093 ; China) ; Lu Huayu
• 刊名：Quaternary Sciences
• 出版年：2013
• 卷期：33(2)
• 关键词：沙地 ; sandy land ; 全新世 ; Holocene ; 内蒙古 ; Inner Mongolia
• 页码：p.243-251
• 图表：illus., 1 table, 44 refs.
• 分类号：1400
• issnNo：ISSN1001-7410
• isbnNo：CN11-2708/P

Hulun Buir dunefield is located at the northwest border of East Asian monsoon area in Northeastern China,  where the environment is sensitive response to advance and retreat of the monsoon precipitation belt during Late  Quaternary. Modern active dune area is situated in the northern and southern part of the Hailar Basin; the other  areas are grassland cover. The dominant aeolian landform types are the stabilized and semi-stabilized sand dunes,  blowouts,sand sheets and shrub-coppice dunes. The prairie in Hulun Buir region is one of the most important  stockbreeding bases in China, but the vegetation degeneration and desertification has become the main eco-  environmental problem. Recent researches have showed that the modern aeolian landform in Hulun Buir dunefield  formed under joint action of natural and human impacts. Therefore, in order to better understand the natural  background of desertification and to guide the production activities of local people, to reconstruct the aeolian  environment change during the characteristic paleoclimate period of Last Glacial Maximum （LGM） and Holocene Optimum（HO） has important scientific and social values. The deposition sequences of aeolian sand beds and sandy plaeosols in Hunlun Buir dunefield are important geological archive of past environmental changes. Aeolian sand beds often lack the organic matter indicating active sand transport with limited vegetation cover. The paleosols represent wetter conditions with much less aeolian activity. With the development of optically stimulated luminescence dating in recent years, it has provided the possibility of dating the aeolian sand beds directly, which are difficult to be dated by radiocarbon dating because of their low organic carbon content.  We had explored the dunefield and took the samples from eight typical sand-paleosol sections. In this study,47 OSL ages were obtained and nearly 200 bulk samples were measured for grain-size and magnetic susceptibility as the environmental proxies. The equivalent doses （De） were determined by the single aliquot regeneration （SAR） protocol using the purified quartz grains（90- 150μm）. Combined with previously published data, it reveals wet-dry variations in Hulun Buir dunefield since 16ka and the desertification area during the LGM and HO. Our preliminary conclusions are that the Hulun Buir dunefield was almost completely desertificated during the LGM, and the boundary of desertificated area extended about 60km northward and 50km eastward compared to the modern boundaries,respectively; the total desertificated area reached at about 22, 337km2 and it is 3.7 times than the modern desertificated area. The mobile sand dunes were nearly completely stabilized during the HO,there was only local short-lived aeolian activity existed in that time. However, these preliminary conclusions need be tested by more OSL ages from the buried sand beds and palaeosols in this sand field where the desertification is still developing.