济源盆地中侏罗统马凹组上段混合沉积特征及其控制因素

摘要

Mixed sedimentation of siliciclastic and carbonate deposits is a kind of deposition that has a special and important sedimentary mechanism. The mixed deposits are well developed in the the upper member of the Middle Jurassic Ma ’ao Formation in the Jiyuan Basin, western Henan, and consist dominantly of compositionally or texturally mixed deposits composed of muddy limestone, limy mudstone and lime-bearing mudstone. The slightly-oxidized and slightly-reduced brackish environments generated in the arid and scorching conditions may facilitate the development of the mixed deposits, which resulted from the combination of the palaeotectonic movements, palaeoclimates and sediment supply. The results of research in this study provide one useful approach to interpreting the sedimentary mechanism and continental mixed siliciclastic and carbonate deposits.%陆源碎屑与碳酸盐混合沉积是一种沉积机理特殊而又有重要意义的沉积现象。目前陆相地层的混合沉积研究相对薄弱。混合沉积在豫西济源盆地中侏罗统马凹组上段较发育，本文综合应用沉积学、沉积地球化学、古生物地层学方法对其特征及控制因素进行了研究。结果表明，研究区马凹组上段发育泥质灰岩、灰质泥岩和含灰泥岩等多种岩性组成的成分混合沉积和由其夹层或互层组成的结构混合沉积，较干燥炎热气候条件及弱氧化-弱还原的半咸水环境有利于混合沉积发育，混合沉积是古构造、古气候和物源供给共同控制的结果。本研究对于充实沉积机理理论有一定的意义，亦为陆相混合沉积研究提供了一个较好的实例。