Abstract: Trace elements data for the coal seams in the Jurassic system are used to assess the sedimentary environments of Yanqi Basin, Xinjiang, China. The concentrations，distribution and occurrences of state about trace elements are discussed. Detailed geochemical characteristics on trace elements reveal that: (1) the content of trace elements is low as a whole, but P, V, Ti values are relatively high, indicating that Yanqi Basin belongs to a kind of inland lake environment; (2) they are concentrated obviously on the edge of the basin, the roof and floor and interlayer of the coal seams; (3) P, Sr, Co show affinities with organic matter, however, Cu and Ti mainly associated with clay minerals; (4) the geochemical features, the colorsof sediments and the appearance of coarse detritus in Xishanyao Formation demonstrate that the coal-accumulating environment was gradually transferring from freshwater to brackish in the Jurassic system, and correspondingly the palaeoclimate was changing from humidity to drought.

Key words: coal, trace elements, Yanqi Basin, palaeoclimate

摘要： 通过对焉耆盆地侏罗系煤层的微量元素研究，分别探讨了微量元素的含量、分布、赋存特征及其成煤环境意义。研究表明，焉耆盆地煤中微量元素总体含量较低，但P、V、Ti等元素则明显富集，属于内陆湖泊盆地；微量元素在盆地边缘和煤层的顶底板及夹矸中明显富集；P元素具有明显的有机亲和性，Cu、Ti等元素主要赋存于粘土矿物中；元素的地球化学特征和沉积物的颜色，以及西山窑组粗碎屑的出现表明，焉耆盆地侏罗系水体由淡水向微咸水逐渐过渡，古气候由潮湿向干旱转变。

关键词: 煤, 微量元素, 焉耆盆地, 古气候