察尔汗盐湖91-Ⅳ_4孔沉积地层元素地球化学的研究

ELEMENT GEOCHEMISTRY OF SEDIMENT IN THE CORE OF 91-Ⅳ_(4) IN QARHAN SALT LAKE

首次利用6步连续化学提取法,探讨和研究了察尔汗盐湖91—Ⅳ_4孔沉积物中16种元素在不同地球化学相中的结合形态和赋存状态。结果表明:碱金属K存在于可交换部分中;碱土金属Mg、Ba存在于碳酸盐相中,Mn在碳酸盐相中的含量也较高;B、P存在于有机质部分中;痕量金属大多存在于易还原相、中等还原相和硅酸盐矿物晶格的残渣部分中。

Element has different existing state in sediment, which can be studied by the method of sequential extraction. In this paper, six steps of sequential extraction developed by Tessier A. , Solomons W. and Forstner U. is used to treat 23 sediment samples of 91- Ⅳ4 core in Qarhan Salt Lake for the first time in China. Sediment is divided into six sediment phases, i. e. exchangeable fraction, carbonate fraction, easily reducible phase, moderately reducible phase, organic fraction and residual fraction. The contents of 16 kinds of elements in six sediment phases are determined with ARL-3520 ICP. Through analysing the proportion of each element in different sediment phases, the authors indicate : (1) alkaline metal K exists in exchangeable fraction; (2) alkaline-earth metals Mg, Ba (they also have higher proportion in exchangable fraction) exist in carbonate fraction, and Mn has higher content in this fraction because the ion radius of Mn2+ is close to those of Ca2+ , Mg2+; (3) B , P exist in organic fraction ; (4) trace metals such as Co, No, Fe, Cr, V, Cu, Ti etc. mostly exist in easily and moderately reducible phases and residual fraction of crystal structure of the silicate mineral.