西北大学学报(自然科学版)

根据重矿物组合、古流向和碎屑颗粒粒度等资料,对鄂尔多斯盆地上三叠统延长组物源区的母岩性质、物源方向及演变特征等进行了分析。结果表明:延长组沉积物主要来自两种类型的母岩,即深变质的结晶片岩和片麻岩、浅海相碎屑岩及碳酸盐岩;在延长组沉积早中期,主要物源来自北部和西南两个方向,而延长组沉积晚期,西南方向物源占优势,北部物源的影响明显减弱,而且物源南北分布特征明显。

Based on analysis of heavy minerals,paleocurrent and clastic particles grading,the sediment of Yanchang section in Ordos Basin comes from two types of parent rock.One of the parent rock is Archaeozoic kataplayicolasegneiss and kataschist in Daqing mountain area.The second parent rock is neritopelagic detrital rock and pyroclastic rock of simian and palaeozoic.The all margin of Ordos Basin in Yanchang period supply provenance.Northern and southwestern are main province area from early period to middle period of Yanchang Formation.Southwestern becomes main provenance area because of its uplift in later period of Yanchang Formation.