星云湖表层沉积物矿物组成及其环境意义

星云湖表层沉积物中的矿物成分主要为粘土矿物、碳酸盐矿物、长英质矿物和铁矿物。从下往上方解石和石英具有消长变化规律,即从下往上方解石含量迅速增加,而石英含量则逐渐降低。这种规律性变化与沉积物中CaO和烧失量的变化具有明显的正相关性。它反映了近年来湖泊富营养化有加剧的趋势。星云湖表层沉积物矿物成分的垂向变化与环境变化的对比分析研究表明,沉积物中自生方解石含量的变化可以灵敏地指示湖泊环境变化,是环境变化研究中一个良好的环境替代指标。

THE CHANGING OF MINERAL COMPOSITION AND ENVIRONMENTAL SIGNIFICANCE IN SURFACE SEDIMENTS OF XINGYUN LAKE

Clay mineral, carbonate mineral, felsic mineral and ferreous mineral are essential mineral in surface sediments of the Xingyun Lake. From below to up, calcite and quartz have a eat and flow rule, i.e. the content of calcite increasing rapidly, and the content of quartz reducing gradually from below to up. The contents of calcite have an obvious positive pertinence as compard with CaO and LOI. These phenomena has shown that the productivity of lake has increased and that the reason that cause the content of calcite and CaO increase is eutrphication.The comparison of the change of mineral composition in vertical section with the environment change shows that the change of the content of autogeny calcite can show the environment change of lake delicacy, which is a good environmental pointer in the study of environment change.