Magnetic properties of Holocene aeolian sand and lacustrine sediments from the Salawusu River Basin
Magnetic susceptibility is a commonly used proxy for paleoenvironmental research.However,the magnetic enhancement mechanism of sediments from different sedimentary environments is different,so the sys-tematic magnetic study is particularly important for the interpretation of the paleoenvironmental significance of magnetic susceptibility.In this study,we selected the Holocene aeolian sand and lacustrine sedimentation section of Dishaogouwan from the Salawusu River Basin to clarify the magnetic properties of different sedimentary fa-cies and explore their variation mechanisms through systematic study of environmental magnetic parameters.The results show that the magnetic properties of aeolian sand and lacustrine sediments are significantly different.The magnetic minerals in aeolian sand are mainly ferrimagnetic magnetite and maghemite,with lower coercivity,higher magnetic minerals concentration,and coarser magnetic grain size,mainly multi-domains and pseudo-sin-gle domains.In addition to ferromagnetic and antiferromagnetic minerals,lacustrine sediments may also contain weakly magnetic iron sulfides,with higher coercivity,lower concentration of magnetic minerals,and finer mag-netic grain size,mainly coarse stable single domains.Magnetic susceptibility of aeolian sand are less influenced by pedogenesis and are mainly influenced by the"dust input mode",with the dominant contribution of coarse-grained magnetite and maghemite to the magnetic susceptibility.The magnetic characteristics of the lacustrine sediments are influenced by the reducing environment of the lake,where the strongly magnetic iron oxides under-go dissolution and conversion to the weakly magnetic iron sulfides,resulting in a decrease in the magnetic grain size,a decrease in the magnetic mineral concentration and an increase in the coercivity.
aeolian sandlacustrine sedimentsmagnetic propertiesSalawusu River Basin
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NSTL
万方数据
维普
