河南鹤壁地幔捕掳体内磷灰石的发现及地幔交代作用  

Discovery of apatite in mantle xenoliths and mantle metasomatism at Hebi,Henan Province

作　　者：秦战营 姜江 任栩颖 齐永安[2] 张艳林 侯广顺[2] QIN Zhanying;JIANG Jiang;REN Xuying;QI Yong’an;ZHANG Yanlin;HOU Guangshun(Henan Province Non-ferrous Metals Mineral Exploration Engineering Reseach Center,Zhengzhou 450016,Henan,China;School of Resources and Environment,Henan Polytechnic University,Jiaozuo 454000,Henan,China;Institute of Sedimentary Geology,Chengdu University of Tech-nology,Chengdu 610059,Sichuan,China)

机构地区：[1]河南省有色金属矿产探测工程技术研究中心,河南郑州450016 [2]河南理工大学资源环境学院,河南焦作454000 [3]成都理工大学沉积地质研究院,四川成都610059

出　　处：《河南理工大学学报（自然科学版）》2024年第1期61-67,共7页Journal of Henan Polytechnic University（Natural Science）

基　　金：国家自然科学基金资助项目(41773024)。

摘　　要：目的地幔交代作用是岩石圈演化的重要方式之一。显性交代作用以出现交代成因的地幔矿物为特征,可为地幔交代作用提供直接证据,磷灰石是地幔中交代成因的典型矿物。中生代以来,太行山构造带东侧的华北板块岩石圈明显减薄,而西侧仍保留较厚的岩石圈,太行山构造带是华北克拉通东部被破坏区与西部稳定区的过渡带。因此,太行山构造带的地幔包体对研究华北克拉通破坏具有重要意义。鹤壁地区位于太行山构造带上,发育有金伯利岩等深源岩浆岩。方法本文以金伯利岩携带的地幔包体为研究对象,探讨鹤壁地区岩石圈地幔的性质。通过人工重砂的方法,从地幔包体中分选出数粒磷灰石和一粒被辉石包裹的磷灰石。结果体视显微镜下,磷灰石无色,透明,具玻璃光泽,呈短柱状;扫描电镜能谱分析表明,被包裹的矿物主要由Ca,P,O,F元素组成,寄主矿物主要由Si,Fe,Mg,Al,O元素组成;电子探针结果表明,磷灰石中w(CaO)为53.525%~56.514%,w(P_(2)O_(5))为37.372%~40.851%;实验岩石学研究认为,顽火辉石+方解石→橄榄石+透辉石+CO_(2),磷灰石等作为副矿物产出。因此,辉石包裹磷灰石的矿物组合属于地幔交代成因,指示了显性交代作用。结论磷灰石这种显性地幔交代成因矿物的发现,为华北克拉通岩石圈地幔经历显性交代作用提供了直接证据。Objective Mantle metasomatism is one of the important ways of lithosphere evolution.Explicit metasomatism is characterized by the occurrence of mantle minerals with metasomatism,which can provide direct evidence for mantle metasomatism.Apatite is a typical mineral of metasomatism in the mantle.Since the Mesozoic era,North China Craton(NCC)lithospheric has significantly thinned occurred at the easten margin of Taihang mountain tectonic belt,while the western part of Taihang mountain remained thicker continental lithosphere.Taihang mountain tectonic belt is the transition zone between the eastern destructed NCC and the western stable NCC.Therefore,it is of great significance to study the mantle xenoliths in the Taihang Mountains tectonic zone for the destructionof the NCC.Hebi Area of Henan Province is located on the Taihang Mountain structural belt,where deep-seated magmatic rocks such as kimberlite are developed.Methods This article takes the mantle xenoliths carried by kimberlite as the object to research the properties of the lithospheric mantle in the Hebi Area.Some apatite particles and a single apatite enclosed in pyroxene particle were found in the man-made heavy minerals from mantle xenoliths.Results Observation through stereoscopic microscope shows that the apatite is colourless,transparent,glassy luster and short colum in shape.Scanning electron microscope energy dispersion spectra shows that the encapsulated minerals are consisted of Ca,P,O,F elements,and the host mineral is consisted of Si,Fe,Mg,Al,O elements.The electron probe results indicate that apatite chemical composition ranges from 53.525%to 56.514%,and w(P_(2)O_(5))ranges from 37.372%to 40.851%.Experimental petrology research suggests that enstatite+calcite→olivine+diopside+CO_(2),and apatite and other minerals are produced as accessories.Therefore,the mineral combination of pyroxene encapsulated apatite belongs to mantle metasomatism,indicating dominant metasomatism.Conclusion The discovery of apatites mantle metasomatism origin provides th

关 键 词：河南鹤壁 华北克拉通破坏 地幔捕掳体 地幔交代作用 磷灰石 

分 类 号：P571[天文地球—矿物学] P581[天文地球—地质学]