干旱区地理2017，Vol.40Issue(3)：494-503,10.
渭河宝鸡市区段河床沉积物磁性特征分析
Magnetic property analysis of sediments at Baoji Section of Weihe River
摘要
Abstract
The provenance of the river sediment can be efficiently traced by using the method of environmental magnetism.According to the analysis of the river sediment's complete and systematic magnetic properties in the main stream and tributaries at Baoji section of Weihe River,the content of magnetic mineral in Weihe River sediments and tributaries is very little.The x (Magnetic susceptibility) mainly reflects the total content of the sediment magnetic mineral and the variation's range ofxlf is 36.4× 10-8 ～ 378.4× 10-8 m3· kg-1 in the main stream of Weihe River,the average value ofxlf is 116.9× 10-8 m3· kg-1,and the variation's ranges in Qingjiang River,Jingling River and Qian River respectively are 36.8× 10-8 ～ 189.4× 10-8 m3· kg-1,54.2× 10-8 ～ 168.1 × 10-8 m3· kg-1 and 54.2 × 10-8 ～ 168.1 × 10-8 m3· kg-1.SIRM (Saturation isothermal remanent magnetization) can well reflect the magnetic mineral concentration of the river sediment.The variation's range of Weihe River main stream sediments is 2.9 × 10-3 ～ 20.3 × 10-3 Am2· kg-1,the average value is 8.6 × 10-3 Am2· kg-1,the variation's range of three main tributaries respectively are 13.2× 10-3 ～ 28.0× 10-3 Am2· kg-1,7.9× 10-3 ～ 9.2× 10-3 Am2· kg-1 and 6.9× 10-3 ～9.6 × 10-3 Am2 · kg-1,the magnetic mineral content of Qingjiang River exceeds that of Weihe River's main stream,Jinling River and Qian River sediments.The xARM (Anhysteretic remanent magnetic susceptibility) reflects the content of the ferrimagnetism mineral,the variation's range of main stream sediments is 3.1 × 10-8～572.1 × 10-8 m3· kg-1,its average value is 135.6× 10-8 m3· kg-1,which is low in general.The variation's range of Qingjiang River,Jinling River and Qian River sediments respectively are 323.4 × 10-8～ 632.7 × 10-8 m3· kg-1,251.7 × 10-8 ～ 552 × 10-8 m3· kg-1 and 81.8 × 10-8～ 190.7 × 10-8 m3· kg-1.In addition,according to the hysteresis loop of representative samples and correlation analysis of SOFT and xlf (r2 =0.91),the main magnetic minerals of samples are low coercivity maghemite,maghemite and high coercivity of antiferro magnetic minerals hematite.The FORC (First-Order Reversal Curve),King Plot and Day diagram indicate that the magnetic mineral in Weihe River sediments and tributaries are mainly pseudo-single domain (PSD) and multiple domain (MD) grains.The magnetic concentration of sediments in Weihe River shows the difference,on the basis of the variation tendency ofxARM/x,the sediment sources can be divided into two parts in Weihe River different section,the value of number of sediments xARM/x gradually decreases in the first part which is from Baoji George to the Shenlong Brige,the magnetic particles becomes coarser,in the second part which is from Shenlong Brige to the border on Qian River and Weihe River,the xARM/x gradually increases,the sediment particle changes from coarse to fine,which clearly indicates that there are some differences in sediment provenance of the Weihe River in Baoji section.The source of main stream sediment in Baoji section of Weihe River is mainly the upstream carry-dominated,from the Shenlong Brige to the downstream,branch stream make a contribution to riverbed sediment,relatively,north shore contributes more substance than south.关键词
渭河/沉积物/环境磁学/物源Key words
Weihe River/sediment/environmental magnetism/provenance分类
天文与地球科学引用本文复制引用
张俊辉,王彦虎,姜珊,周旗,刘引鸽..渭河宝鸡市区段河床沉积物磁性特征分析[J].干旱区地理,2017,40(3):494-503,10.基金项目
陕西省教育厅科学研究计划重点项目资助(17JS014,13JS010) （17JS014,13JS010）
