【摘要】 前人对塔里木盆地巴楚地区T74界面的研究主要以在地震反射剖面中大的不整合面形式为基础进行的,对界面具体的岩性、微相和成岩作用研究较少。位于塔里木盆地巴楚县东北方向一间房地区的T74露头剖面为上奥陶统与中—下奥陶统的分界面,岩性以生物碎屑泥粒灰岩和粒泥灰岩为主。镜下分析表明:T74界面生屑灰岩中生物碎屑以棘皮动物(主要为海百合碎片)和介形虫为主,其他生物碎屑包括腕足动物、软体动物、三叶虫、钙球粒、粗枝藻、龙介虫、有孔虫、海绵和苔藓等。通过镜下微相、C-O同位素以及X射线荧光等多种分析方法,认为T74界面地层沉积相为较温暖的低能陆棚相,后期经历了埋藏压实成岩作用、地层抬升后的淡水成岩作用和风化剥蚀作用等。岩石的缝合线发育,孔渗性较好,利于地下流体的运移和渗透,对中—下奥陶统的岩溶发育起着控制作用。更多还原

【Abstract】 The T47 boundary outcrop profile is located in the north-east Bachu County,Tarim Basin,which separate Upper Ordovician and Middle-Lower Ordovician.The lithology of this boundary is bioclasts packstones and wackstones.Based on the microfacies analysis,the bioclasts rich in biospecies mainly consist of echinoids especially in crinoids and ostrocods.Other bioclasts include brachiopod,mollusc,trilobite,calcispher,dasycladus,serpulid,foraminifera,sponges and bryozoan.Analysed by microscopes,carbone-oxygen isotope and X-ray fluorescent analysis and so on,the results show that the strata of T47 boundary formed in the warm and lower energy shelf facies and subsequently experienced burial compact diagensis,meteoric diagensis and weathering diagensis following the strata uplifting.The development of stylolite with good porosity and permeability is favour of fluids movement in the subsurface and is an important factor to the development of karst in MiddleLower Ordovician.更多还原