重矿物分析在古地理研究中的应用--以准噶尔盆地南缘中段古近系紫泥泉子组紫三段为例

The application of heavy mineral analysis to palaeogeographic research:a case study of the 3rd Member of Ziniquanzi Formation in the central southern margin of Junggar Basin

通过对准噶尔盆地南缘中段紫泥泉子组紫三段(E1-2z3)的166件重矿物样品分析,综合古近纪紫泥泉子期的区域构造、气候、沉积物特征等因素,提出古近纪紫三段沉积期的古地理环境为:干燥气候条件下,发育同方向、多河道、间歇性辫状河,水浅、源多、坡缓的古地理环境。多条河流平行发育和迁移,河道垂直岸线伸展、各种沉积相带却平行岸线展布,相带宽度较大。

Based on an analysis of 166 heavy mineral samples from the 3rd Member of Ziniquanzi Formation （E1-2^z^3） in the central southern margin of the junggar Basin and taking into account such factors as regional structure, climate and sediment characteristics, the authors have reached the following conclusions： the palaeogeographic conditions for the deposition of the 3rd Member of Ziniquanzi Formation were dry, with the development of multi-channel and intermittent braided rivers in the same direction characterized by shallowness, multiple sources and gentle slopes. A number of parallel rivers were developed, moved and extended vertical to the shoreline. Nevertheless, various kinds of sedimentary facies with a fairly great width were spread parallel to the shoreline.