鄂尔多斯盆地白垩纪沙漠石英沙颗粒表面特征

沉积环境的判别是沉积盆地分析、古地理、古气候研究和储层评价的重要手段。石英具有较大的硬度和较高的化学稳定性,因而其沉积物颗粒表面特征能很好地反映沉积环境,而通过扫描电镜研究石英颗粒表面微细特征是分析沉积环境行之有效的方法。尽管鄂尔多斯盆地早白垩纪志丹群存在沙漠沉积已被广为接受,但石英颗粒表面微细特征分析还比较薄弱。对采自鄂尔多斯盆地白垩纪志丹群洛河组 (K₁l)和罗汉洞组 (K₁lh)的沙丘沙进行石英颗粒表面微细特征分析的结果表明,其石英沙颗粒表面特征具有明显的风成特征,及易与水成特征相区别。因此,本研究从石英沙颗粒表面特征方面进一步肯定了鄂尔多斯盆地白垩纪古沙漠的存在

Microscopic Features on Quartz Sand Grain Surface in the Cretaceous Desert of Ordos Basin

The determination of depositional environments is an effective means for basin a nalysis, palaeogeography and palaeoclimate study and oil reservoir judgement. Qu artz has relative high hardness and chemical stability, therefore its sedimentar y grain surface features can well reflect the depositional environments. And usi ng electronic scan microscope to study quartz grain surface microscopic features is also an effective method to analyze depositional environments. Although it h as been widely accepted that there occurred desert sediments in the early Cretac eous Zhidan Group in the Ordos Basin, the systematic analysis of quartz sand grain surface microscopic features is lack. This paper shows the result of the quartz sand grain surface microscopic feature analysis from the Louhe Formation and Luohandong Formation of the early Cretaceous Zhidan Group in the Ordos Basin . It reaches that the microscopic features are of distinct eolian characteristic s and the analysis can easily distinguish eolian from hydrogenic sediments. Ther efore, our study confirms the existence of the Cretaceous desert in the Ordos Ba sin with the respect of quartz sand surface microscopic features.