【作者】 赵庆英；

【导师】 徐学纯；

【作者基本信息】 吉林大学 ， 矿物学、岩石学、矿床学， 2004， 硕士

【摘要】 早期古大陆的重建 早期大陆地壳的性质和演化已成为现代地球科学的重要前沿课题之一 而孔兹岩系是地壳发展早期高级变质地区一套较特征的变质沉积岩系其特征和成因研究对查明这类地区早期地壳形成和演化过程 具有重要的科学意义内蒙古大青山地区是中国孔兹岩系的主要发育地区之一 以往的研究者在此做了大量的研究工作 积累了丰富的地质资料 发表了大量论文和专著 但是 对于内蒙古大青山地区所发育的一套钙硅酸盐岩系组成的变质沉积地层 由于在其它地区零星出露 因而没有给予足够的重视 而对孔兹岩系的成因研究 普遍把重点放在诸如石英岩 矽线石榴片麻岩 石墨片麻岩之类的明显代表孔兹岩系中原始地层组分的岩石组合上 而对作为孔兹岩系中的主要岩石组合之一 钙硅酸盐岩组合 如钙硅酸盐 白云质大理岩等 却很少有系统地研究 而钙硅酸盐岩组合在系统地研究孔兹岩系的原岩建造 沉积盆地的构造环境和演化 以及前寒武纪早期大陆地壳的特征都有着十分重要的意义 　 本文在充分了解和掌握前人资料和研究成果的基础上 通过对内蒙古大青山地区发育完整的孔兹岩系 进行系统地分析研究 查明了这套孔兹岩系的空间展布规律 岩石组合特征 地层层序及岩石学特征 并根据岩石地球化学特征 利用多种原岩恢复图解 恢复了本区孔兹岩系的原岩建造 进而深入讨论了这套孔兹岩系的原岩建造类型以及原岩的沉积环境 取得以下一些认识 　 研究区内变质地层十分发育 是内蒙古中西部地区早前寒武纪变质地层分布较 I<WP=86>摘要广 发育齐全 特征明显的典型区域 孔兹岩系在研究区内广泛发育 根据其岩石学特征 将其划分为 榴云片麻岩岩组 透辉片麻岩岩组及大理岩岩组这三套岩石组合 在地层层序中 它们构成相应的岩性段 这三个岩组空间关系密切 多处以互层或夹层相伴产出 各个岩组之间以构造关系接触 大多呈近东西向条带状展布局部地区零星出露的孔兹岩 呈不规则团块状 补丁状及透镜状 这套孔兹岩系的三个岩组的地层层序自下至上依次为 榴云片麻岩岩组 透辉片麻岩岩组 大理岩岩组 　 榴云片麻岩岩组是一套富铝片麻岩系 以富含石榴石 矽线石 堇青石等富铝变质矿物为特征 主要岩石类型为 石榴黑云片麻岩 石墨 石榴 片麻岩 石榴长英片麻岩 浅粒岩 等 其岩石地球化学以富铝 富铁 富镁 贫钙 贫碱为特点 其中 Al2O3与 SiO2呈明显负相关性 反映了由粘土质岩 颗粒状陆源碎屑岩之间连续的地球化学序列 微量元素中 Rb Yb Y 具明显亏损 而其它元素普遍富集 稀土元素总量相对较高 轻稀土富集 分馏程度较高 略具 Eu 负异常 其原岩为以泥质岩为主的泥岩 粉砂岩 杂砂岩 复矿物砂岩和长石石英砂岩 以碎屑沉积为主 　 透辉片麻岩岩组是一套钙硅酸盐岩系 以富含透辉石 榍石 方柱石和磷灰石为特征 主要岩石类型为 透辉片麻岩 透辉长石岩 长石透辉石岩 透辉石岩透辉大理岩 其岩石地球化学以贫硅 富碱及碱土元素为特点 Al2O3 含量变化较大 SiO2与 CaO MgO 呈负相关 与 Al2O3 (K2O Na2O)呈正相关 反映了钙硅酸盐系机械沉积作用与化学沉积作用叠加的沉积特征 微量元素以富 Sr Ba TaTh 为特点 稀土元素总量相对较高 L/H 值较高 分馏程度高 大多具有 Eu 负异常 其原岩为含钙质长石砂岩 钙质杂砂岩 钙质泥岩夹泥灰岩 镁铁质泥灰岩以碎屑沉积为主 有不同程度的化学沉积加入 II<WP=87>摘要 大理岩岩组是一套富镁质的大理岩系 以巨厚的 大面积分布的白云质大理岩的发育为特征 底部有少量碎屑岩沉积 矿物组成除白云石外 普遍含蛇纹石化橄榄石 透辉石 金云母等一种或多种富镁硅酸盐矿物 岩石地球化学以富 CaO MgO和 LOI 为特征 反映了碳酸盐岩的地球化学特征 CaO MgO 达 44.96 以上 且CaO/MgO 较小(1.37-10.94) 其原岩应为一套碎屑含量极低的白云岩 以化学沉积为主 　 榴云片麻岩岩组和透辉片麻岩岩组的原岩源区风化程度中等 其中的碎屑来源是以其下伏兴和岩群的麻粒岩或与之类似的层状岩石为主 榴云片麻岩岩组的源区岩石相对富铁镁质 而透辉片麻岩岩组碎屑的源区岩石相对富长英质 研究区内孔兹岩系 总体上表现出一个从碎屑沉积 有化学沉积加入的碎屑沉积 化学沉积这样一个较大的沉积旋回 这些原岩建造的变化显示出其沉积环境的变化 反映出水体中含盐度逐渐增加的特征 也表现出海平面逐渐升高的特点 原岩建造的沉积环境 由初期的陆海过渡的三角洲相 过渡到滨海 浅海相最后到干燥气候条件下有障蔽岛相隔的封闭海盆相 构造环境也从亚稳定状态过渡到稳定构造环境 表明这套变质沉积地层的原岩可能形成于被动大陆边缘 但更类似于中元古界长城系 蓟县系这样的克拉通内裂陷槽或裂谷沉积更多还原

【Abstract】 Reconstruction of early palaeo-continent, properties and evolution of earlycontinental crust has become one of significant front problems of contemporarygeoscience. But the Khondalite series is a suit of characteristic metasedimentary rockseries in the high-grade metamorphic region in early continental crust development. Theresearch of its characteristic and research of origin has important scientific significant forprobing into the evolution process of the early continental crust formation of this typeregion. Daqingshan region of Inner Mongolia is one of regions that Khondalite series mainlydeveloped in China. A great quantity of study work had been done by formerresearchers accumulated rich geological data a great quantity of papers and monographswere issued. But they didn’t pay more attention to a suit of metamorphic deposit strataconsist of calcium silicate developed in the Daqingshan region, Inner Mongolia, becausethey distributed discontinuity outcrops in else region. But the most research of origin ofkhondalite series had been done for quartzite, sillimanite garnet gneiss and graphitegneiss which represent obvious rock association of original strata component ofkhondalite series. But the calcium silicate rock assemblages which is one of main rockcomponent of khondalite series ( In case calcium silicate, dolomite-marble etc. ), yetseldom systematically researched. But the calcium silicate rock assemblages areimportant significant for systematically researching protolith formation, the tectonic IV<WP=89>英文摘要environment and evolution of depositional basin and the characteristics of earlycontinental crust of the Precambrian. The paper basis on sufficiently to former data and research achievements find outthe distribution in space, the characteristic of rock composition, stratigraphic sequence,lithogeochemical characteristics, protolith formation of this suit of khondalite serieswhich developed in the Daqingshan region, Inner Mongolia, by systematically analysisresearching. The protolith formation has been restored based on lithogeochemicalcharacteristics and varied protolith recovery diagrams, further discussing about types ofprotolith formation and depositional environment of protolith of this suit of khondaliteseries. Below knowledge acquired Widely developed metamorphic strata in researching region is the characteristicobviously typical region of metamorphic strata of early Precambrian distribute widely inthe middle-west part of Inner Mongolia. Khondalite series in the studying region widelydeveloped they were divided into three rock groups basis on the characteristic ofpetrology: garnet biotite gneiss rock group, diopside gneiss rock group and marble rockgroup, they compose relevant member of rock component within strata sequence. Thespace relationship among three groups are closely links they are interbedded orinterlayers in most output contacted by the structural relationship among every rockgroup extending near east to west in striped for majority. The khondalite series in thelocal region are discontinuity outcrops, presenting irregular in block likely, patch shapeand lens shape. The stratigraphic sequence of three rock groups of this suit of khondalite series frombottom to top are Garnet biotite gneiss rock group, diopside gneiss rock group and marble V<WP=90>英文摘要rock group. The garnet biotite gneiss rock group is one suit gneisses series of rich in aluminum.It is character of rich containing garnet, sillimanite and cordierite etc.. The main rocktypes are garnet biotite gneiss, graphite ( Garnet ) Gneiss, garnet felsic gneiss ( lightgranulite ) etc. Its lithogeochemistry is character of rich in aluminium, iron, magnesiumand deficient in calcium and alkali. Al2O3 presents obvious negative correlation againstSiO2, presenting continuously geochemistry sequence between clay r更多还原