【摘要】 对巢湖西部柱样以及杭埠河流域土壤的环境磁学研究表明,磁铁矿是决定磁性特征的主要磁性矿物,杭埠河流域是巢湖西部沉积物的主要来源．靠近巢湖西岸的柱样AC1砂含量较高,X、SIRM值较大而xARM／SIRM较低,说明磁铁矿含量较高、颗粒较粗．距岸稍远的柱样AC2砂含量较低,X、SIRM值也较低,其变化与XARM较相似,与粘土含量变化也有一定程度的相似,AC2沉积物X、SIRM值较ACI小,但XARM／SIRM较高,说明磁铁矿含量较低且颗粒较细．杭埠河流域土壤的磁性测量结果表明,砂、砾含量高的粗骨土磁性最强,富含粗颗粒磁铁矿．巢湖柱样沉积物砂的含量随踞岸远近而不同, 反映了沉积环境的水动力不同,由此产生明显的磁性特征差异,实质是对沉积动力的响应．研究表明磁性参数XARM／SIRM 可以间接反映沉积物中粘土含量的高低变化．更多还原

【Abstract】 Magnetic study on core sediments from western Lake Chaohu and soils from Hangbu River Catchment suggests that magnetite is the dominant magnetic mineral, and soils from Hangbu River Catchment are the main source of lake sediments. Core AC1 near the bank shows higher proportion of sands and higher X. SIRM values but lowerXARM/SIRM values, indicating higher concentration of magnetite with coarse size. Core AC2 more far away from the bank shows lower proportion of sands and lower X. SIRM values. The similar variations of X, SIRM with XARM,and to a lesser degree with clay fraction, in combination with higherXARM/SIRM values, indicating lower concentration of magnetite with fine size. Magnetic properties of soils in the catchments indicate that skeletal soils with abundant sand and gravel fraction are magnetic strong which are contributed by coarse magnetite. Content of sand fraction in core is a reflection of water energy which is dependent on the distance to the bank. Therefore, the distinct magnetic properties of different cores are due to sedimentary dynamics. It is found thatXARM/SIRM can be used to indicate the variation of clay contents in sediments.更多还原