Magnetic properties and their relationships with particle size of sediments from Maigang Resevoir, Guizhou Province, China

Abstract

对贵州省麦岗水库沉积物环境磁性特征的研究表明,亚铁磁性矿物主导了沉积物矿物磁性特征,但同时也存在反铁磁性矿物等其他矿物,超顺磁颗粒在沉积物中广泛存在.在所选矿物磁性参数中,_χlf、_χfd、SOFT与粒度不相关;_χARM、SIRM、F₃₀₀与粒度相关,但相关系数不高;_χARM/_χlf、_χARM/SIRM和粒度显著相关,可以作为粒度的代用指标.研究结果显示,磁性参数确实可以作为粒度的代用指标.但对比研究表明,在不同沉积环境,甚至相似沉积环境的沉积物中,矿物磁性参数和粒度的关系可能不同,在特定沉积环境中,利用磁性参数作为粒度的代用指标应该在充分研究的基础上进行,使研究结果更为可靠.;Three sediment cores were extracted from Maigang Reservoir, located in the southwest of Guizhou Province, China. Ferrimagnetic minerals are the main magnetic minerals of the sediments. There are also other magnetic minerals, for instance, antiferromagnetic component. Super-paramagnetic grains were widely observed in the sediments. There is no significant relationship between mineral magnetic parameters, _χlf, _χfd, SOFT and textural parameters. Mineral magnetic parameters, _χARM, SIRM, F₃₀₀ is correlated with textural parameters but with low correlation coefficients; Given the significant correlations between _χARM/_χlf, _χARM/SIRM and textural parameters, _χARM/_χlf, and _χARM/SIRM can be used as a proxy of particle size. Results presented here do indicate that mineral magnetic parameters can be used as a particle size proxy. These data and other studies on different environments demonstrate that the relationship between mineral magnetic parameters and textual properties can vary from different sedimentary environments even in the same overall sedimentary system, and in some circumstances, mineral magnetic parameters are not suitable to be particle size proxy. To employ magnetic characteristics as a particle size proxy, the mechanism behind the relationship between magnetic parameters and particle size should be explored fully for each sedimentary environment.