| 烧变岩岩石学及稀土元素地球化学特征 |
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| 引用本文： | 黄雷,刘池洋.烧变岩岩石学及稀土元素地球化学特征[J].地球科学,2008,33(4). |
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| 作者姓名： | 黄雷 刘池洋 |
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| 作者单位： | 西北大学大陆动力学国家重点实验室(黄雷)，西北大学含油气盆地研究所(刘池洋) |
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| 基金项目： | 国家重点基础研究发展计划(973计划)
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教育部长江学者奖励计划 |
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| 摘 要： | 烧变岩的研究有益于对煤层形成以来所经历的构造运动、古气候和古地理的探讨.为了获得有关烧变岩基本特征的数据资料,本文利用扫描电镜、能谱测试、古地磁及ICP-MS等测试手段对陕北神木地区烧变岩进行了系统的岩石学及稀土元素地球化学的分析研究.剖面上将烧变岩分成烧熔岩和烧烤岩两个序列.扫描电镜观察及能谱测试显示,各矿物均显示烧熔迹象,除伊利石外未发现其他类型粘土矿物;磁化率测试显示烧变岩具异常高的磁化率;地球化学分析显示烧变岩稀土元素配分特征近于沉积岩(原岩)特征;纵向剖面上,随烧变程度增大(由烧烤岩至烧熔岩)其稀土元素总量逐渐减小,烧熔岩稀土元素总含量较烧烤岩的要明显低;另外,烧熔岩表现为较明显的Ce负异常,而烧烤岩则表现为无Ce异常,有些甚至表现为偏正异常.
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| 关 键 词： | 烧变岩 矿物岩石学 磁化率 稀土元素 Ce负异常. |
Petrologic and REE Geochemical Characters of Burnt Rocks |
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| HUANG Lei,LIU Chi-yang.Petrologic and REE Geochemical Characters of Burnt Rocks[J].Earth Science-Journal of China University of Geosciences,2008,33(4). |
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| Authors: | HUANG Lei LIU Chi-yang |
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| Institution: | Northwest University |
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| Abstract: | The study of burnt rocks faciliates the discussion on the tectonic movement,paleoclimate and paleogeography that coal seams were subject to after they were formed.In order to obtain the basic data on the features of the burnt rocks,a systematic study of petrology and REE geochemistry on burnt rocks in Shenmu,North Shaanxi Province,has been done,using the methods of SEM,EDS,susceptibility measurements and ICP-MS.The burnt rocks are divided into two series in the section:the melted rocks and the baked rocks.SEM and EDS analyses reveal that all the minerals show burnt and melted traces,and there are no clay minerals except illite found in the burnt rocks.Susceptibility measurements reveal that the burnt rocks have abnormally high susceptibility values,whereas a geochemical analysis shows that the REE distribution pattern of burnt rocks is similar to that of sedimentary rocks(initial rocks).In the longitudinal section,the REE gradually decreases as the burning degree increases(from baked rocks to melted rocks),and the total REE of melted rocks is obviously lower than that of baked rocks.Besides,the melted rocks show apparent negative Ce anomalies,while the baked rocks show no anomaly of Ce,and sometimes even show positive anomalies. |
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| Keywords: | burnt rock mineral petrology susceptibility REE negative Ce anomaly |
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