CAJ | 학술논문

条带状铁建造（banded iron formation ，BIF）是前寒武纪地层中广泛发育的一类富铁沉积岩，它在华北克拉通内广泛发育。在华北克拉通南缘的舞阳地区，晚太古代太华群铁山庙组BIF包含石英-磁铁矿和辉石-磁铁矿两种组合，前者的绝大部分磁铁矿颗粒均自形程度高、粒度粗大并常常紧密伴生有一定量的方解石。舞阳地区铁山庙组BIF的RAMAN ，SEM ，CL和EDS分析结果表明：石英-磁铁矿矿石中的磁铁矿自形程度最高、石英次之、方解石最低；方解石似条带的RAMAN分析结果指示其有序度、结晶程度沿条带的垂直方向无规律突变，明显不同于裂隙中后期热液流体沉淀形成的方解石脉；方解石发生了塑性流变并最终定位于石英和磁铁矿间的间隙内，其矿物的截面形状和展布特征明显受控于石英和磁铁矿并得到了石英颗粒间微裂隙内方解石的证实；方解石似条带的微区成份存在明显差异，这反映方解石经历了塑性流变及再次汇聚；在磁铁矿颗粒的汇聚及生长过程中，方解石充当了磁铁矿微颗粒迁移的媒介并得到了方解石中磁铁矿微颗粒局部富集现象的证实。
조대상철건조（banded iron formation ，BIF）시전한무기지층중엄범발육적일류부철침적암，타재화북극랍통내엄범발육。재화북극랍통남연적무양지구，만태고대태화군철산묘조BIF포함석영-자철광화휘석-자철광량충조합，전자적절대부분자철광과립균자형정도고、립도조대병상상긴밀반생유일정량적방해석。무양지구철산묘조BIF적RAMAN ，SEM ，CL화EDS분석결과표명：석영-자철광광석중적자철광자형정도최고、석영차지、방해석최저；방해석사조대적RAMAN분석결과지시기유서도、결정정도연조대적수직방향무규률돌변，명현불동우렬극중후기열액류체침정형성적방해석맥；방해석발생료소성류변병최종정위우석영화자철광간적간극내，기광물적절면형상화전포특정명현수공우석영화자철광병득도료석영과립간미렬극내방해석적증실；방해석사조대적미구성빈존재명현차이，저반영방해석경력료소성류변급재차회취；재자철광과립적회취급생장과정중，방해석충당료자철광미과립천이적매개병득도료방해석중자철광미과립국부부집현상적증실。
The results of Raman ,SEM ,CL and EDS analysis show that the quartz-type BIF (banded iron formation) in Tieshan-miao formation ,from Wuyang area of south North China Craton mainly contains quartz ,magnetite and a small quantity of cal-cite .In comparison ,magnetites represent the highest automorphic degree ,while calcites contribute to the lowest automorphic degree .In addition ,the automorphic degree of the quartz lies between magnetite and calcite .In the results of Raman analysis , the crystallinity and order degree are quite diverse in the vertical direction of the calcite band-like ,and this is different from the calcite vein precipitating from the upper hydrothermal fluid .There are obvious plastic flow happening to calcite particles .During the process of plastic flow ,the calcites are finally filled in the space between quartz and magnetite .This is the reason why the cross sectional shape and distributional characteristics of calcite aggregate are controlled by the particles of quartz and magnetite , which is also evidenced by the calcite filled into the slight interspace between two particles of quartz .In the Raman analysis , there are apparent differences of microarea component in calcite band-like ,and this denotes that it is produced by the plastic flow and concourse process .What’s more ,the calcite acts as the migration intermedium of tiny magnetite during their concourse and crystallization processes ,which is witnessed by the concentrated particles of magnetite in small size in local parts of the calcites . With the help of calcite ,the small magnetite particles join together to crystallize with bigger size or form aggregate of minerals .