鄂西震旦系灯影组白鸡河锌矿床地质特征及成因探讨

在鄂西震旦系白云岩地层中,新发现了白鸡河锌矿床、凹子岗铅锌矿床、冰洞山铅锌矿床。白鸡河锌矿床矿石成分简单,富锌贫铅;矿石结构主要为细晶结构、交代结构;矿石构造变化大,存在角砾状、浸染状、纹层状、条带状及"雪顶"构造;成矿温度低,白云石化交代角砾岩作用普遍;矿石硫同位素为重硫,值域很宽,闪锌矿与方铅矿在相对封闭环境沉淀。矿床地质特征可与MVT型铅锌矿床相类比,成因为碳酸盐岩容矿的后生沉积铅锌矿床。     

中扬子二叠系碳酸盐岩岩相模式

从相分析着手,重点剖析京山、崇阳两条岩相剖面,系统地研究了岩石、古生物、地球化学组分及分布规律。在此基础上提出了中扬子二叠系碳酸盐岩岩相模式。二叠系碳酸盐岩属台地碳酸盐岩岩相,包括潮坪、局限台地、台地浅滩、开阔台地A、开阔台地B、边缘浅滩、斜坡等七个次级相。该模式较合理地解释了中扬子二叠系碳酸盐岩的发育规律,并对硅质岩、白云岩的成因提出了新认识。     

华北地台南部下古生界有利储集层类型及分布

华北地下古生界储集层主要存在四种类型:古岩溶型、同重结晶作用有关的白云岩型、同构造作用有关的裂缝型和粒屑灰岩型。其中古岩溶型最为有利,其次为白云岩型和构造裂缝型,粒屑灰岩型则相对较差。在纵向地层中,认为最有利的储层分布在奥陶系碳酸盐岩古岩溶中,其次在上寒武统白云岩中。表生期岩溶作用是风化壳储层形成的最根本原因,孔隙型白云岩储层大多受岩性控制。太参3井及其以西、和鄂尔多斯西南缘的陇县、礼泉地区白云岩储层与古岩溶型储集层相互组合比较好,是有利储集层发育区。     

Element geochemistry of weathering profile of dolomitite and its implications for the average chemical composition of the upper-continental crust

Geochemical behavior of chemical elements is studied in a dolomitite weathering profile in upland of karst terrain in northern Guizhou. Two stages can be recognized during the process ofin situ weathering of dolomitite: the stage of sedentary accumulation of leaching residue of dolomitite and the stage of chemical weathering evolution of sedentary soil. Ni, Cr, Mo, W and Ti are the least mobile elements with reference to Al. The geochemical behavior of REE is similar to that observed in weathering of other types of rocks. Fractionation of REE is noticed during weathering, and the two layers of REE enrichments are thought to result from downward movement of the weathering front in response to changes in the environment. It is considered that the chemistry of the upper part of the profile, which was more intensively weathered, is representative of the mobile components of the upper curst at the time the dolomitite was formed, while the less weathered lower profile is chemically representative of the immobile constitution. Like glacial till and loess, the “insoluble” materials in carbonate rocks originating from chemical sedimentation may also provide valuable information about the average chemical composition of the upper continental crust.     

鄂尔多斯盆地奥陶系马家沟组五段上部沉积成岩特征与天然气聚集

本文将沉积、成岩和储集性三者结合起来研究，建立了泥云坪压实沉积成岩相区、含膏云坪岩溶孔洞沉积成岩相区，膏泥云坪浅凹压 实交代充填沉积成岩相区等 三种沉积成岩类型，分析了各相区的沉积构造特征，成岩特征，储集性能，指出了含膏云坪岩溶孔沉和只成岩相带是天然气富集的最有利储集相带。