【作者】 管清玉；

【导师】 潘保田；

【作者基本信息】 兰州大学 ， 自然地理学， 2006， 博士

【摘要】 气候变化研究一直是近十几年来地学界研究的重点和热点之一。距现代全新世间冰期最近的间冰期——末次间冰期由于其记录承载体较丰富、分辨率较高、相互之间可比性较强，因此使其成为理解目前全新世间冰期气候自然变化的最佳选择对象。紧随末次间冰期之后的末次冰期，其环境格局与末次间冰期大相径庭。虽然当今的温室效应使全球平均气温居高不下，但是对末次冰期环境进行详细研究，这对于目前人类来说意义仍然重大。因此，末次冰期旋回以来的气候变化研究也就成为研究的重中之重。 中国的黄土研究在20世纪90年代前后曾经一度辉煌，取得了令人瞩目的成果，当时的黄土沉积成为可以与冰芯、深海记录相媲美的陆相沉积。但是，由于大多数黄土剖面其沉积速率较低、分辨率不高，从而限制了研究的进一步深入。就末次冰期旋回而言，黄土记录中还存在较大的差异，特别是末次间冰期内差异更大。这些差异是黄土地层所承载气候信息本身的差异，还是由载体后天的变异所引起的?这需要一些比较可靠的、新的剖面来加以验证。然而，黄土高原中部大多数剖面由于沉积速率较低(特别是S1地层)，加上后期强烈的成壤作用和淋溶作用可能影响其气候记录。大多数黄土地层由于其所固有的缺陷，限制了对其研究的进一步深入。幸运的是，在中国的一些特殊地理区域，的确存在末次间冰期的一些厚层黄土剖面，其沉积速率与分辨率都特别高。本论文所着重研究的、分别位于六盘山东西两侧的河南三门峡王官剖面与甘肃武威沙沟剖面，仅就S1而言，东西两剖面中其厚度分别为12.5米、11.6米，其末次间冰期时段的沉积速率分别高达23cm／ka、21cm／ka。对此类黄土剖面的进一步发掘、研究将有助于探讨东亚季风区气候变化的一些细节与机制问题。 通过对王官剖面与沙沟剖面的对比研究，发现此两剖面的S1地层包括5个古土壤层与4个黄土层，并且它们在形成时间上彼此对应较好，指示了末次间冰期所发生的5次强夏季风事件和4次强粉尘堆积事件。说明在末次间冰期无论是东亚冬季风还是东亚夏季风在此两地都存在多次波动反复，同时也暗示东亚季风在末次间冰期很有可能存在较大不稳定性，远非以前所认为的“三峰两谷”的模式。从代用指标的变化幅度上来看，在末次间冰期，东亚冬季风变化幅度远小于夏季风变化幅度，并且冬、夏季风分别对东亚季风区的西部和东部施加了更多影响。研究发现，无论是从两剖面的地层上还是从各代用指标曲线上，都明确指示MIS更多还原

【Abstract】 Climatic change is a hotspot of recent research in geoscience. Since there are abundant records with high resolution and comparability in the last interglacial, which is close to present Holocene interglacial, the last interglacial become the best period to study climate change in current Holocene interglacial. Though the last glacial, following the last interglacial, has quiet different climate environment with the last interglacial and recently greenhouse effect brought high temperature for the world, it is also important for modern human to study the climate environment during the last glacial in detail. So, the study of the period after the last glacial/interglacial cycle became a key in those important studies of climate change.As Chinese loess records were terrestrial sediment that could be compared to those records in ice core and deep-sea in 1990’s, scientists did lots of studies about loess records and made great success. However, limited by low resolution and sedimentary rate in most loess profiles, it is difficult to take further study. Regarding last glacial/interglacial cycle, there are great differences in loess records, especially in the last interglacial. Did those differences represent different climate information recorded in loess stratigraphies? Or were caused by subsequent changes in loess? To answer those questions, we need some new profiles that are more responsible. But, low sedimentary rate in many profiles, especially in S1, and following strong pedogenesis and eluviation would have effect on those climate records. So, the inherent problem limits advanced study of loess profiles. Fortunately, in some special areas of China, there are some thick loess profiles with higher resolution and sedimentary rate, which were formed in the last interglacial. And in this thesis, we discussed two profiles, Wangguan profile in Sanmenxia, Henan Province and Shagou profile in Wuwei, Gansu Province, which are located in east and west side of Liupan Mountains, respectively. With respect to S1, the thickness of S1 in the two profiles is 12.5 m and 11.6 m and the sedimentary rate in the last interglacial period is 23 cm/ka and 21 cm/ka, respectively. To explore and study those loess profiles with high resolution and sedimentary rate would be helpful to investigate some problems about mechanism of climate change in East Asia monsoon region.Comparing Wangguan profile with Shagou profile, we found that both of the two profiles have 5 palaeosol and 4 loess layers in S1 and the time of formation correspond to each other. It represented that strong summer monsoon occurred 5 times and dust deposited 4 times in the last interglacial. It demonstrated that not only East Asia winter monsoon but also East Asia summer monsoon fluctuated many times in both areas. At the same time, it also suggested that East Asia monsoon was probably unstable in the last interglacial and was far from the former mode. According to the extent of proxies’ change, East Asia winter monsoon fluctuated less than East Asia summer monsoon and the former more influenced the west areas of East Asia monsoon region while the latter更多还原