临夏盆地晚新生代沉积物元素特征与古气候变迁  

Late Cenozoic Element Characters and Palaeoclimatic Change of the Lacustrine Sediments in Linxia Basin,China

作　　者：宋春晖[1] 鲁新川[1] 邢强[1] 孟庆泉[1] 夏伟民[1] 刘平[1] 张平[1] 

机构地区：[1]兰州大学西部环境教育部重点实验室&资源环境学院,兰州730000

出　　处：《沉积学报》2007年第3期409-416,共8页Acta Sedimentologica Sinica

基　　金：国家自然科学基金委项目(批准号:90211013;40334038);国家重点基础研究发展计划(973计划)(编号:2004CB720201);国家教育部科学技术研究重大项目(编号:306016)资助

摘　　要：青藏高原东北临夏盆地发育较完整的晚新生代地层,特别13～4.34Ma段以稳定低能细粒湖相沉积为主、发育的不同尺度和各种形式沉积韵律旋回记录着古气候变化信息。本文通过对临夏盆地稳定细粒湖相沉积物元素地球化学特征及其变化序列研究,结合其它气候指标,揭示13～4.4Ma时段气候演化经历了四个阶段:13～12Ma期间气候湿润、12～7.8Ma期间气候以湿润为主夹短暂干旱事件、7.8～6.2Ma期间气候以干旱为主、6.2～4.4Ma期间气候进一步干旱加剧,并认为7.8Ma左右的气候转型可能与冬季风加强有关,而6.2Ma以来的有规律的高频气候波动可能与现代季风形成有关。The late Cenozoic stratigraphy is widely distributed in the Linxia Basin in the southeastern part of the Tibetan Plateau, China. Especially in 13 -4.34 Ma, the Lacustrine sediments are mainly stably fine grain with low energy, the different time scales and sorts of sediment rhythms in this era record much paleoclimatic changes. On basis of research of the element geochemistry of these stably fine lacustrine sediments and sediment rhythmic series in the Linxia Basin, we find four stages of the paleoclimatic evolution throughout the whole time in this basin. Firstly, it is relatively humid at beginning during 13 - 12 Ma, and then it is still humid with some very short dry-events in the period of 12 -7.8 Ma. It turns relatively drier than before in 7.8 -6.2 Ma, and at last it becomes drier and drier with high frequency climate oscillations since 6.2 Ma. The climatic reforming in 7.8 Ma is thought as the possible result of the strength of the winter monsoon, and the regulated climatic changes since 6.2 Ma maybe relate to the modern monsoon.

关 键 词：元素 古气候 湖相沉积物 临夏盆地 晚新生代 

分 类 号：P512.2[天文地球—地质学] P534.63