呼伦湖地区扎赉诺尔晚第四纪湖泊沉积物的磁化率变化及其影响因素

MAGNETIC SUSCEPTIBILITY OF THE LATE QUATERNARY LACUSTRINE SEDIMENTS AND ITS INFLUENCE FACTORS IN JULA NUR, HULUN LAKE AREA

呼伦湖盆地扎赉诺尔晚第四纪湖泊沉积物为砂、泥质碎屑沉积。对东露天矿剖面沉积物样品进行了低、高频磁化率测量、粒度分析、磁性矿物成分鉴定和Al～2O～3、Fc～2O～3含量分析。分析表明:磁铁矿是沉积物磁化率的主要贡献者,全铁含量控制了磁化率值的变化;磁化率与沉积物粒度呈负相关。进一步讨论认为,磁性矿物主要为粉砂-粘土级碎屑,集中分布在细粒沉积物中,因此造成其磁化率较高。砂质沉积物中频率磁化率较高,其原因可能是其中的磁性颗粒比粉砂-粘土级沉积物中的磁性颗粒更细一些。

The late Quaternary lacustrine sediments in Jula Nur of Hulun Lake basin consist of sandy and muddy clastic deposits. The low and high frequence magnetic susceptibility of the samples from of East Open Cut Mine section has been measured. Also, grainsize, magnetic minerals and contents of Fe2O3, Al2O3 of the samples have been analysed. The results indicate that magntite is the main contributor of magnetic susceptibility of sediments, and the total Fe content controls the changes of the magnetic susceptibility which correlates negatively with the grainsize of the sediments. Further study shows that the magnetic minerals are mainly silt-clay clastic deposits, resulting in higher magnetic susceptibility. The frequence-dependent susceptibility of sandy deposits is very high, due to finer magnetic grain than those in silt-clay clastic deposits.