柴达木盆地北缘西段古近系路乐河组沉积相特征研究

Sedimentary facies of Paleogene Lulehe Formation in western segment of northern margin of Qaidam Basin

对柴达木盆地北缘西段古近系路乐河组沉积相进行了分析,共识别出冲积扇、扇三角洲、辫状河、辫状河三角洲与湖泊等5种沉积相类型,并对其各自的沉积特征进行了详细研究。岩相古地理研究表明,柴北缘西段发育2种主要的沉积体系组合类型,西北的冷湖—潜西地区为冲积扇—扇三角洲—湖泊沉积体系组合,东南部马海—南八仙地区则为冲积扇—辫状河—辫状河三角洲—湖泊沉积体系组合。

Based on outcrop observation, core description, well logging and seismic data, the sedimentary facies of Paleogene Lulehe Formation in northern margin Qaidam Basin is analyzed. Five types of seidimentary facies are identified： alluvial fan facies, fan delta facies, braided stream facies, braided delta facies, lacustrine facies, of which the sedimentary characteristics are studied. The lithology and paleogeography in Paleogene Lulehe Formation indicates that there mainly developed two sets of depositional system assemblages. Depositional environment attributes to alluvial fan- fan delta-lacustrine environment system in Erboliang-Lenghu zone of northwestern Qaidam Basin and alluvial fanbraided stream-braided delta-lacustrine environment system in Mahai-Nanbaxian zone of southeastern Qaidam Basin.