中文摘要：

通过青藏高原腹地可可西里边缘地区BDQ0608钻孔岩芯分析,表明其岩性主要为浅绿色湖相沉积物,其中夹杂部分较薄的氧化色层段。热退磁表明：BDQ0608钻孔中磁性矿物主要有磁铁矿、磁赤铁矿、针铁矿和胶黄铁矿,赤铁矿表现不太明显,其组分含量直接控制磁化率值的大小;并且对样品进行了磁化率、粒度、总有机碳及色度的测定。磁化率的大小与黏土含量呈正相关,可能是由于沉积物后期形成的胶黄铁矿及砂性沉积物中磁性矿物被破坏的缘故。并且将磁化率值与总有机碳及色度a＊值对比,发现它们都呈正相关,但内部出现不同的波动形式,说明磁化率值的高低变化并不是与其它指标有完全一一对应的关系,而受沉积时期的环境条件所影响。因此,我们认为磁化率作为环境代用指标能很好的反映环境的变化,但在恢复古环境古气候的过程中要慎重使用,并且要结合其它高精度的环境指标使用,以提高对过去环境恢复的精度。

英文摘要：

A 106 m long sediment core named BDQ0608 was drilled from the Hohxil area in hinterland of the Tibet Plateau,and the lithology is mostly reseda lake sediments with part of a thin oxide color layer.The thermal demagnetization indicates that magnetic mineral in BDQ0608 core mainly includes magnetite,maghemite,goethite,melnikovite,and trace hematite.Magnetic susceptibility was directly related to the composition of magnetic mineral.Magnetite,which abounds in sandy and argillaceous samples,was considered to derive from the detrital minerals in the basin and be a major contributor to magnetic susceptibility of the whole core.The hematite and goethite generated under post-oxidation and oxidation-reduction conditions are both low-magnetic minerals,so they have relatively little contributions to the magnetic susceptibility.Furthermore,it should be specially pointed out that ferromagnetic iron sulfide which dominates magnetism of sediments in the argillaceous sediments would induce much higher magnetic susceptibility than the others.In addition,magnetic susceptibility,grain size,TOC and color reflectance were analyzed at 10 cm intervals.The positive correlation between magnetic susceptibility and clay content is attributed to the destruction of the mucus pyrite formed late and magnetic minerals from sand sediments.Meanwhile,comparing magnetic susceptibility with TOC and color reflectance a＊ separately,the results indicated that there are both positive correlation between them,which may be mainly affected by temperature and humidity.On the one hand,high TOC content implied that the climate during this period was warm and humid corresponding to high lake water level,which could avoid destroying magnetic minerals in the sediments.On the other hand,it was beneficial to the generation of ferromagnetic sulfide in the lakes with high TOC content.The amount of hematite could have a certain contribution to the change of magnetic susceptibility,but it mainly dominated red degrees value（color reflectance a＊ values） of sedime