【摘要】 准噶尔盆地南缘下白垩统内部的层序及界面单纯在地震剖面或电测曲线上都较难识别,但它们在岩石地球化学等特征上有较明显的反映。研究发现,层序边界处具有Ro值的突变,有机质含量(TOC)的低谷,ΔlogR曲线处于基线,粘土矿物组合突变,坡缕石、伊/蒙混层的含量明显增加;Cu、Li、Zn、Cr、V、Ba等微量元素的含量处于低谷;锆石等稳定重矿物含量以及黄铁矿含量较低,褐铁矿含量高等特征。结合地震剖面、测井曲线等特征,将准噶尔盆地南缘下白垩统划分出2个三级层序,每个层序又分别由低位体系域、湖侵体系域和高位体系域组成。更多还原

【Abstract】 Sequence and sequence boundaries of the lower Cretaceous in the southern Junggar basin are difficult to be identified via seismic sections and well logs, but they are obvious in their geochemical characteristics. Some microcosmic features, such as vitrinite reflectance(R o),heavy minerals, gravel component, organic content ,trace elements, as well as seismic section and well logging curves, may efficiently be used to divide the lower Cretaceous of the southern Junggar Basin into two third order sequences. The sequence boundaries usually correspond to excursion of R o Depth curves, lower abundance of organic matter, lower value of the ΔlogR, abrupt change of clay mineral assemblages, lower content of trace elements(Cu, Li, Zn, Cr, P) , lower content of zircon and pyrite and higher content of limonite. Sequence boundary Ⅰ(Sb1) and Ⅲ(Sb3) could be obviously distinguished on seismic sections and well profiles. Lowstand, transgressive and highstand systems tracts can be recognized in each sequence.更多还原