青海湖沉积物的穆斯堡尔效应研究

A Mossbauer Spectroscopic Study of Sediments from Qinghai Lake

对青海湖南岸QH86CK钻孔和湖中心水下QH85 -1 4钻孔的 3 6个沉积物样品进行了穆斯堡尔谱学测量。QH86CK钻孔样品常温下的穆斯堡尔谱由一个Fe2 + 双线分裂 ,一个Fe2 + 双线分裂和一个Fe3 + 六线分裂组成 ,而QH85 -1 4钻孔样品的谱可分解为两个Fe2 + 双线分裂和两个Fe3 + 双线分裂。在低温下 ,QH86CK钻孔样品的谱中出现了一个较强的Hhf=49 3T的磁分裂 ,而QH85 -1 4钻孔样品只有很小一部分Fe3 + 离子表现出磁有序。两个钻孔样品含铁矿物组成及其相对含量不同。QH86CK钻孔样品的Fe2 + Fe3 + 比值随深度有较大变化 ,而QH85 -1 4钻孔各个样品的Fe2 + Fe3 + 比值差别很小。

Mossbauer spectroscopy has been used to study the samples in sediments of core QH86CK on the south shore and core QH85-14 under the water in the center of Qinghai Lake. The RT(room temperature) spectra of the samples of core QH86CK are fitted to a ferrous quadrupole doublet, a ferric quadrupole doublet and a ferric sextet. In the RT spectra of the samples of core QH85-14 show two ferrous and tow ferric quadrupole doublet. At low temperature a larger quantity of the ferric ions in the samples of core QH86CK are magnetically ordered with a hypefine field of 49.3T. On the other hand,the LT spectra of the samples of core QH85-14 show that only a negligible small fraction of the Fe^(3+) ions order magnetically. The components of the iron-bearing minerals and their relative quantity of both cores are different. The Fe^(2+)/Fe^(3+) rations of the samples of core QH86CK varies in different depths. But these rations of the samples of core QH85-14 exhibit only minor variations from sample to sample. The result show that the sedimentation environments of the south shore and under the water in the center of Qinghai lake are different.