临夏盆地黑林顶剖面沉积物在8.6Ma前后岩石磁学特征及其意义  

Rockmagnetic Characteristics of the Sediments from Heilinding Section in the Linxia Basin at 8.6 Ma and Their Implications

作　　者：闫晓丽[1] 张启波[1] 方小敏[2,1] 苗运法[2] 昝金波[1] 孟庆泉[1] 宋春晖[1,2] 张涛[1] 迟云平[1] 

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,兰州730000 [2]中国科学院青藏高原研究所盆地与资源环境研究中心,北京100085

出　　处：《沉积学报》2010年第6期1190-1197,共8页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(批准号:40771214;40872029);中国科学院知识创新工程重要方向项目(编号:kzcx2-yw-104)资助

摘　　要：通过对临夏盆地黑林顶剖面晚新生代沉积物的岩石磁学研究,揭示在11.8～8.6Ma磁化率波动较小,基本保持相对稳定的低值(0.58～6.9/10-8m3kg-1);从8.6Ma开始受软磁性矿物控制明显持续增加(0.75～10.6/10-8m3kg-1)。通过沉积物磁学性质与环境变化之间的模式分析,结合盆地周围构造条件研究,认为物源的变化可能是造成黑林顶剖面磁化率增强的主要原因。The Linxia Basin is a key place to study the paleoclimate change and the Tibetan Plateau uplift for its special place at the Asian monsoon margin and the northeastern Tibetan Plateau.Variations of the magnetic susceptibility and rockmagnetic characteristics from the Heilinding sediments in the Linxia Basin revealed a huge change occurred at the about 8.6 Ma based on a ideal palaeomagnetic dating（11.8-5.0 Ma） .During 11.8-8.6 Ma,the value of the magnetic susceptibility was stably low（0.58-6.9 /10-8 m3kg-1） .After 8.6 Ma,it became very high（0.75-10.6 /10-8 m3kg-1） for the soft mineral magnetic properties.We argued such change was mainly caused by the change of the material origin driven by the uplift of the Tibetan Plateau.The magnetic susceptibility in the lake sediments is different from the loess-paleosol layers in the explanation of the environment and climate change.

关 键 词：临夏盆地 磁化率 物源 构造运动 晚新生代 

分 类 号：P534.63[天文地球—第四纪地质学]