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›› 2017, Vol. 40 ›› Issue (3): 494-503.

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Magnetic property analysis of sediments at Baoji Section ofWeihe River

ZHANG Jun-hui1,2, WANG Yan-hu1,2, JIANG Shan1,2, ZHOU Qi1,2, LIU Yin-ge1,2   

  1. 1 College of geography&Environment, Baoji University of Arts and Sciences, Baoji 721013, Shaanxi, China;
    2 Shaanxi Key Laboratory of Disasters Monitoring&Mechanism Simulation, Baoji University of Arts and Sciences, Baoji 721013, Shaanxi, China
  • Received:2016-09-07 Revised:2017-01-12 Online:2017-05-25

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 χ(Magnetic susceptibility)mainly reflects the total content of the sediment magnetic mineral and the variation's range of χlf is 36.4×10-8~378.4×10-8 m3·kg-1 in the main stream of Weihe River,the average value of χlf 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 χARM(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 χlf(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 of χARM /χ,the sediment sources can be divided into two parts in Weihe River different section,the value of number of sediments χARM /χ 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 χARM /χ 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.

Key words: Weihe River, sediment, environmental magnetism, provenance

CLC Number: 

  • P318