疏勒河冲积扇绿洲全新世古水文演化释光年代学  

Optical dating of Holocene water-laid sediments recorded hydrological environmental changes in the Oasis of Shulehe river alluvial fan in Gansu Province

作　　者：赵华[1] 卢演俦[2] 王成敏[1] 毛洪亮[1] 张克旗[2] 

机构地区：[1]中国地质科学院水文地质环境地质研究所,石家庄050061 [2]中国地震局地质研究所地震动力学国家重点实验室,北京100029

出　　处：《核技术》2007年第11期893-898,共6页Nuclear Techniques

基　　金：国家自然科学基金(40472155)资助

摘　　要：对甘肃疏勒河冲积扇前缘细土带3个具有代表性剖面的12个样品进行了光释光(OSL)年代测定,分别采用不同组分(粗颗粒、细颗粒)、不同技术(单测片再生(SAR)、简单多片再生(MARA)法)进行OSL测年,并相互对比检验,同时与有机碳^(14)C测年结果相互对比,探讨冲积扇前缘复杂的沉积相中沉积物释光测年技术的可行性和可靠性。根据12个样品释光年龄测定值和8个样品有机碳^(14)C测年结果,结合疏勒河绿洲全新世沉积层序、岩性、岩相以及不同沉积相与地下水溢出带的空间分布关系的观测资料,初步提出了疏勒河冲积扇地下水溢出带空间移动的时间框架。To establish the timing of Holocene hydrological environment changes in the front oasis of Shulehe fiver alluvial fan in Hexi Corridor in Gansu Province, twelve water-laied sediment samples collected from three Holocene strata profiles have been dated by quartz OSL, as well as eight samples of organic silt-mud or silt-peat by 14↑C. For OSL dating the SAR protocol of coarse quartz was used for ten samples, and the fine grain fraction SAR and MARA protocols for four samples. Comparison of OSL ages obtained from the coarse quartz SAR with those from both the fine grain SAR and the MARA for same samples shows a good agreement within a standard deviation. The cross check between OSL ages and 14↑C ages for four group samples within same or contiguous layers is accepted in measurement error. On the basis of all age estimates obtained from both OSL and 14↑C, and of analysis of field observation data, an elementary timing of Holocene hydrological environment changes, i.e. shifts of groundwater spilling belt, in the front oasis of Shulehe fiver alluvial fan is suggested in this paper.

关 键 词：石英光释光测年 全新世 水文环境 疏勒河冲积扇 

分 类 号：P597[天文地球—地球化学]