鄂尔多斯盆地延长组长7油层组碳酸质喷积岩初探

鄂尔多斯盆地延长组长7油层组黑色岩系中首次发现主要呈纹层状、脉状等顺层分布于油页岩或凝灰岩中的碳酸质岩浆—热液喷流型沉积岩（简称喷积岩），具有重要的研究价值。通过野外露头和钻井取心观察，薄片鉴定，扫描电镜、电子探针、全岩元素分析等测试方法，对上述碳酸质喷积岩的岩石学、矿物学、地球化学以及与生烃母质关系特征进行了初探。结果显示，按物质来源、形成方式和结构构造可将长7油层组碳酸质喷积岩划分为碳酸质喷爆岩、碳酸质喷溢岩、碳酸质喷流岩三大类型，三者主量元素、微量元素、稀土元素等地球化学特征具有岩浆碳酸岩和热水沉积岩的双重特征，且与生烃母质的发育具有正相关性。因此，碳酸质喷积岩在鄂尔多斯盆地延长组长7油层组黑色岩系沉积期发育，且对长7油层组生烃研究具有重要的理论和实际意义。

A Preliminary Study of Carbonatite Magmatic-hydrothermal Exhalative Sedimentary Rock of the Chang 7 Member,Yanchang Formation,Ordos Basin

Carbonatite magmatic?hydrothermal exhalative sedimentary rock （ESR） was first discovered in the oil shale or tuff in the black rock series of the Chang 7 member of the Yanchang Formation， Ordos Basin. It is mainly characterized by its growth along the layering of the laminated and veined structure. For the obviously important research value of this discovery， the carbonatite ESR was initially subjected to petrological， mineralogical， and geochemical analysis， and its relationship with hydrocarbon-generation materials was examined in field outcrop sections and drill cores， thin sections， scanning electron microscope （SEM） analysis， electron probe microanalysis， whole-rock element analysis， and other methods. These studies categorized the carbonatite rock material source， formation mode， texture and structure， into three types: explosive， effusive and exhalative-hydrothermal rock. All three types contain the major elements， trace elements and rare earth elements （REE） of carbonatite and hydrothermal sedimentary rock. They exhibit significant positive correlation with hydrocarbon-generation materials， and are of considerable theoretical and practical significance for further investigation of hydrocarbon potential in the area.