张家口下花园青白口系下马岭组灰质页岩热模拟实验

华北地区中上元古界地层烃源岩的有机质热演化普遍处于高成熟－过成熟阶段，而张家口下花园青白口系下马岭组页岩和灰质页岩的Rb仅有0.38-0.6%，处于低成熟阶段，是系统研究中上元古界地层的生烃模式及有机质热演化特征的较理想模拟实验样品。本次模拟结果表明：模拟温度在275℃以前（R0＜0.80%)为低成熟阶段，275℃－350℃（R0为0.8-1.32%）为成熟阶段；其中325℃（R0为1.16%)为生油高峰，350℃（R0为1．32％）为轻质油高峰，350℃－410℃（R0为1．32－2．0％）为高成熟阶段，410℃以后（R0＞2．0％）为过成熟阶段。随着温度升高，生成的烃类和干酪根碳同位素（δ^13)逐渐变重，验证了δ^13C存在温阶效用。在过成熟阶段，可溶有机质亦发生了芳核的缩聚反应，使芳烃含量减少，大分子的沥青质含量增多。可溶有机质在高成熟－过成熟阶段有“逆转”现象，正构烷烃碳数分布出现了双主峰，高碳数部位出现了奇偶优势等特征。当Rb>0.81％以后，同一温度点为Rb%>R0%。无水与加水模拟实验对比表明，加水实验的液态烃产率高，液态烃中重组分相对含量多，说明无水实验中热裂解反应强烈，而加水实验更接近地层热演化条件。     

东天山尾亚岩体锆石SHRIMP定年及其地质意义

鉴于缺少系统、精确的同位素定年,前人对尾亚岩体成岩时代仍有颇多争议。本文利用锆石离子探针(SHRIMP)定年技术,测定了尾亚岩体不同相带的年龄,旨在进一步探讨该岩体的形成演化与区域构造作用的关系。定年结果表明,辉长岩、石英正长岩、石英闪长玢岩和细粒花岗岩年龄分别为236     

辽宁红透山块状硫化物矿床中矿体的变质变形特征与形成过程

辽宁红透山块状硫化物矿床位于华北克拉通北缘,是中国最大的太古宙块状硫化物矿床.该矿床经历了高级角闪岩相变质变形和后期热液改造.通过野外和矿相学观察,将红透山矿床的主要矿石类型划分为4类.块状矿石呈层状和块状构造,等粒状和变晶结构;粗晶状矿石呈透镜状和块状构造,巨斑状和填隙结构;糜棱岩化矿石又称矿石糜棱岩,矿石呈透镜状和...     

东天山黄山岩体的侵位时代及其地质意义

东天山黄山—镜儿泉地区分布有众多镁铁质—超镁铁质岩体,岩体成群成带分布,受区域性韧性剪切带和断裂构造控制.为进一步确定黄山—镜儿泉基性—超基性岩带的侵位时代、成因和大地构造背景,对选自黄山岩体辉长岩相中单颗粒锆石进行了LA-ICP-MS U-Pb定年研究,将其结果[(284.5±2.5)Ma]与黄山岩体和黄山—镜儿泉一带其他基性—超基性岩中已有的定年成果进行了对比,并结合近年来该区研究成果,分析得到黄山辉长岩侵位于晚石炭世—早二叠世,此时正值东天山后碰撞大规模岩浆侵位和成矿时期.黄山镁铁质—超镁铁质岩带形成于后碰撞的伸展构造环境.     

Hydrothermal Mobilization and Enrichment of Iron in the Iron Deposits of the Middle—Lower Yangtze Valley District

There are two main types of iron deposits in the Middle-Lower Yangtze Valley district.Both of them underwent post-magmatic hydrothermal processes during ore formation.Iron in the hydrothermal ore bodies was derived largely through mobilization from substantially consolidated diroitic intrusives.Wall-roch alteration zonation indicates that iron-mobilizing hydrothermal fluids evolved in a trend of decreasing alkalinity,which is suggested by regularly distributed wall-rock alterations formed by iron-mobilizing hydrothermal fluids and is in contradiction with the current chloride,chloride complex and bicarbonate models for iron mobilization.The close association of carbonatization with iron ores and the high concentrations of reduced gases such as CO,CH4 and H2 in fluid inclusions suggest that iron is most probably transported in the form of iron carbonyls during post-magmatic hydrothermal processes. In the light of the iron carbonyl mobilization model,explanations are made of the constraints on ores of some geologic factors such as melanocratic alteration,carbonatization,carbonate strata,structural fractures,cyptoexplosive pipes and embryo ores.