盐湖沉积物的穆斯堡尔效应研究

A Mossbauer Spectroscopic Study of Salt Lake Sediments

对青海柴达木盆地察尔汗、昆特依盐湖以及新疆罗布泊盐湖一系列沉积物样品进行了穆斯堡尔效应的研究。对全部样品做了常温下的穆斯堡尔谱学测量,并对部分样品做了低温下的测量。从穆斯堡尔谱的解析结果可知,盐湖沉积物黏土矿中含二价铁的主要矿物是绿泥石,在察尔汗盐湖样品中有少量菱铁矿;三价铁存在于多种矿物和非晶态的氢氧化物中;某些样品中含有少量的赤铁矿,它在常温下即出现磁有序。不同盐湖的沉积物样品和同一盐湖不同深度样品的含铁矿物组成及相对含量不同,Fe2+/Fe3+的比值也不同。这些结果可以反映出盐湖沉积过程中地球化学和环境及气候的变化。

A series of samples of the sediments from Chaerhan and Kunteyi Playa in Qaidam basin and Luobubo Playa in Xinjiang have been studied by Mossbauer spectroscopy.All samples were measured at room temperature.Some samples were also measured at low temperature.The spectral components of the Mossbauer spectra of the samples are attributed to Fe^(2+) ions in chlorite and siderite (the latter is contained in the samples of Chaerhan Playa only), Fe^(3+) ions in manifold clay minerals and in amorphous ferric hydroxides, and partly in hematite.The components of the iron-bearing minerals and their relative quantity are dependent on the lakes and on the depths.And the Fe^(2+)/Fe^(3+) ratios of the samples vary in different lakes and different depths.The results reflect the different geochemical and climatic environment during the sedimentation process of salt lakes.