古氧相分析在黄骅拗陷歧南次凹沙河街组沉积环境研究中的应用

Application of paleo-oxygen facies analysis to the sedimentary environment research of the Paleogene Shahejie Formation in the south Qikou sag,Huanghua depression,China

把古氧相分析理论与方法应用于黄骅拗陷歧南次凹古近系沙河街组沉积环境研究之中,通过古氧相分析中的微量元素V/Cr和Ni/Co分析,以及岩石与古生物分析表明,歧南次凹沙河街组具有以常氧为主、贫氧为辅的沉积环境;同时,古盐度分析指示为咸水、半咸水环境,地球物理学(地震、布格重力异常)研究结果为深水封闭湖泊环境,对比分析认为歧南次凹沙河街组为内陆深水咸化湖泊环境。在环境地质标志研究基础上进行沉积环境研究时,采用古氧相分析与古盐度分析等综合研究,可以有效避免将内陆咸化湖泊环境误判为海相或过渡相环境。

This paper introduces the application of the paleo-oxygen facies analysis to the study of the sedimentary environment in the Paleogene Shahejie Formation in the south Qikou sag.The trace elements（V/Cr,Ni/Co） analysis in the paleo-oxygen facies analysis shows the aerobic and dysaerobic environment in the Paleogene Shahejie Formation in the south Qikou sag.In the meantime,the paleosalinity（Sr/Ba and Ca/（Ca＋Fe）） analysis indicates the salt and brackish water environment.The seismic and Bouguer gravity anomaly data show the abyssal and closed environment.The contrast of the paleo-oxygen facies,paleosalinity and geophysical analysis results shows the terrestrial abyssal and salty lacustrine facies of the Paleogene Shahejie Formation in the south Qikou sag.Finally,there is a suggestion that the comprehensive paleo-oxygen facies,paleosalinity and geophysical analysis can avoid taking terrestrial abyssal and salty lacustrine facies as the marine-continental transitional facies or marine facies.