【作者】 张振；

【导师】 宋春晖；

【作者基本信息】 兰州大学 ， 第四纪地质学， 2007， 硕士

【摘要】 昆仑山垭口盆地位于青藏高原腹地的东昆仑山脉中段，地理位置独特，盆地内广泛发育的巨厚晚上新世至第四纪中期沉积物详细记录了区域构造、气候变化的演化历史，是研究青藏高原隆升和新生代气候环境演化的理想地区。本文通过对昆仑山垭口盆地晚上新世以来沉积记录的系统研究，主要获得了以下结论和认识：①通过对昆仑山垭口盆地2.58-0.5Ma时段高分辨率磁化率指标变化序列的分析，并与大西洋深海氧同位素曲线对比，昆仑山垭口盆地沉积物磁化率与气候变化的关系为：磁化率的低值与气候偏温湿对应；反之，则与气候偏冷干一致。②通过对昆仑山垭口盆地2.32～0.5Ma时段高分辨率湖相沉积物各组粒度变化序列的分析，并结合孢粉等研究资料以及与大西洋深海氧同位素曲线及黄土高原黄土-古土壤记录曲线的对比，认为湖相沉积物7.8-63μm粒级百分含量变化能够较敏感的反映古气候变化，其低值反映气候暖湿，高值则代表气候冷干。③通过对比分析，昆仑山垭口盆地磁化率与粒度指标曲线自2.32Ma以来具有较好的可对比性，其中磁化率和粒度的高值(低值)分别对应且变化趋势总体一致，可以互相验证。同时，两者共同揭示昆仑山垭口盆地气候变化经历了5个不同阶段：2.58～1.95/1.94Ma，气候温湿；1.95/1.94～1.82Ma，气候冷干；1.82～1.07Ma，气候总体温和稍湿，其间有数次冷干波动；1.07～0.81/0.82Ma，气候向冷干发展；0.81/0.82～0.5Ma，气候向更加冷干发展。④用REDFIT3.8对昆仑山垭口盆地2.32～0.5Ma时段高分辨率粒度指标的功率谱分析表明，垭口盆地该时段的气候变化对轨道尺度(23～100ka)的变化周期均有反映，同时亦存在千年、万年、数十万年尺度的气候不稳定振荡，变化受多个气候驱动因子共同作用，既反映了与全球气候变化同步的信息，同时也表现出其明显的区域性特征。昆仑山垭口盆地的气候变化外力因素主要为太阳辐射；中高纬度、青藏高原、边缘海和热带海洋可能为较重要的内力因素，其中青藏高原晚上新世以来的大幅构造隆升可能是昆仑山垭口盆地一带气候干旱化转型的驱动机制和动力。更多还原

【Abstract】 Kunlun Pass Basin is located in the middle of the East Kunlun Mountains of the Qinghai-Tibet Plateau,which is in the unique geographical position.Basin-wide development of thick sediments from the late Pliocene to middle Quaternary detailed records of the regional structure.The evolution of climatic change history is to study the Tibetan Plateau uplift of the Cenozoic climate and the evolution of the ideal region.Based on the Kunlun Pass Basin sedimentary since the new system of records,access to the following conclusions and perspective:①Through the Kunlun Pass Basin 2.58～0.5Ma period of high-resolution magnetic susceptibility indexes sequence analysis,and the deep Atlantic Seaδ¹⁸O curves contrast,Kunlun Pass Basin sediments susceptibility and the relationship between climatic change: the low magnetic susceptibility and humid climate counterparts;otherwise,with the cold and dry climate agreement.②Through the Kunlun Pass Basin 2.32～0.5Ma period of high-resolution lake sediments grain size of the group changes the sequence,and pollen,and other research materials as well as the deep Atlantic Seaδ¹⁸O curves and the Loess Plateau loess-paleosol record curve,contrast that lacustrine sediments 7.8～63μm particle percentage change to reflect more sensitive ancient climatic change,reflect its low warm climate;otherwise,with the cold and dry climate.③By contrast,the Kunlun Pass Basin susceptibility and grain size indicators since 2.32Ma has been better comparability,with the grain size and magnetic susceptibility of high value（low） corresponding with overall trend line and can verify.Meanwhie,they always revealed the climatic change of Kunlun Pass Basin has five different periods: 2.58～1.95/1.94Ma,humid climate; 1.95/1.94～1.82Ma,cold and dry climate;1.82～1.07Ma,climate overall warm and slightly wet,but there have been several cold and dry oscillations;1.07～0.81/0.82Ma,to be cold and dry climate;0.81/0.82～0.5Ma,developing to a more cold and dry climate.④The power spectral analysis of Kunlun Pass Basin 2.32～0.5Ma period high-resolution grain size by REDFIT3.8 showed that the climatic change of Kunlun Pass Basin during this period on the scale track（23¹00ka） cycle changes are reflected,also exist millennium and a few hundred thousands years-scale oscillation of climate instability.Climatic change have been driven by many factors,and reflects not only global climatic change synchronized information,but also demonstrate its obvious regional characteristics.The main external factors of climatic change of Kunlun Pass Basin was solar radiation;within the internal factors,high latitude,Qinghai-Tibet Plateau,risk factors and tropical sea marine were perhaps the most important,in which the great uplift of Qinghai-Tibet Plateau since late Pliocene maybe the driven dynamic mechanism and power of the climatic change and climate developing to dry in Kunlun Pass Basin.更多还原