150ka以来内蒙古河套古大湖沉积物粒度记录的湖泊水位变化  

Variation of lake water level recorded by grain sizes of sediments from Hetao Paleolake since 150ka

作　　者：杨星辰[1] 叶培盛[1] 蔡茂堂[1] 常鹏渊 游报捷 李成路 叶梦旎 蔡惠慧[2] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地质通报》2017年第6期1043-1050,共8页Geological Bulletin of China

基　　金：中国地质调查局项目<内蒙古1:5万呼勒斯太苏木(K48E017024);塔尔湖镇(K48E018024);复兴城(K48E019024);吉尔嘎朗图乡幅(K48E020024)填图试点>(编号:12120114042101);中国地质科学院地质力学所所长基金(编号:DZLXJK201609)

摘　　要：基于内蒙古河套盆地山前兵房沟湖相层剖面沉积物的粒度记录,结合^(14)C和光释光年代学测试,对比分析沉积物粒度敏感粒级及频率曲线特征,反演了河套古大湖150ka以来的湖泊水位变化。研究结果表明,河套古大湖水位变化经历了4个阶段:(1)初始形成阶段(150~130ka),河套古大湖处于浅湖环境,沉积物粒度由粗变细,湖泊处于水位上升期;(2)发展阶段(130~54ka),早期湖水面较高,处于深水环境,晚期沉积物粒度逐渐变粗,湖泊水位有所下降;(3)萎缩阶段(54~18ka),湖泊水位快速下降,细粒沉积物含量减少,中粗粒沉积物含量增大,湖泊水位迅速下降;(4)消亡阶段(18ka至今),由于山前活动断裂影响,阴山快速隆升,湖泊急剧萎缩,湖相层顶部被山间冲洪积物覆盖。控制河套古大湖湖泊水位变化的主要因素是构造运动和气候环境突变。Based on size data of Bingfanggou lacustrine sedimentation section,which lies in Hetao basin piedmont, combined with chronologic test of ^(14)C and OSL, the authors comparatively analyzed sediment particle size sensitivity and frequency curve characteristics, and made inversion of the lake water level change of Hetao Paleolake since 150 ka. The result indicates that the lake water level change of Hetao Paleolake has gone through four stages :(1)Initial forming stage(150~130ka): Hetao Paleolake was in a shallow lake environment, sediment particle sizes were from coarse to fine, and the water level of the lake was in rising period;(2)Developing stage(130~54ka): the lake surface was higher in deep water environment early, sediment particle sizes gradually became thicker and the lake surface declined;(3)Contraction stage(54~18ka): the lake water level dropped rapidly, the fine-grained sediments decreased, and the coarse-grained sediments increased;(4)Demise stage(18ka-now): due to the influence of active faults in piedmont, the Yinshan Mountain uplifted rapidly, the lake atrophied swiftly, the top of the lacustrine strata was covered by diluvial and alluvial materials between the mountains. The main factors controlling the water level change of the paleolake seem to have been the tectonic movement and abrupt change of climate environment.

关 键 词：河套古大湖 粒度 水位 ^(14)C 光释光 

分 类 号：P512.2[天文地球—地质学]