准南山前断褶带紫泥泉子组层序地层及岩相古地理

Sequence Stratigraphy and Lithofacies Paleogeography in Ziniquanzi Formation in Piedmont Fault-fold Belt, Southern Margin of Junggar Basin

通过露头与钻井、测井资料的对比研究,依据紫泥泉子组存在两个区域稳定发育的大套泥岩,以及区域不整合、河道下切面或沉积体系转换面,将准噶尔盆地南缘山前断褶带古近系紫泥泉子组划分为2个三级沉积层序,建立研究区层序地层格架。编制了以层序为单位的岩相古地理图,探讨了层序地层格架内的古近系紫泥泉子组沉积期间岩相古地理特征及沉积演化。其中,紫泥泉子组沉积早期(层序一)岩相古地理格局为冲积扇、辫状河-辫状河三角洲-湖泊共存;紫泥泉子组沉积晚期(层序二)湖泊扩张,为以湖泊沉积为主的辫状河-辫状河三角洲-浅湖沉积组合。

The correlation study of outcrop and drilling-well logging data shows that Ziniquanzi formation of Paleogene in piedmont faultfold belt in southern margin of Junggar basin can be divided into two 3-order sequences with which sequence stratigraphy framework of the studied area is set up, based on existing two sets of mudstones in regional and steady development of Ziniquanzi formation, regional unconformity and erosion surface or sedimentary system interface. The lithofacies paleogeography map is drawn in terms of sequence. The feature and evolution of lithofacies paleogeography during Ziniquanzi deposition period within this framework are discussed. The early period of it （Sequence Ⅰ） is characterized by co-existing alluvial fan, braided river-braided channel delta and lake facies; the late period （Sequence Ⅱ） by the expanding lake and the assemblage of braided river-braided channel deha-lake facies dominated by lake deposit.