冀东彭庄铍矿角砾岩锆石U-Pb年龄及其地质意义  

Zircon U-Pb Age and Geological Significance of the Breccia in Beryllium Deposit of Pengzhuang,Eastern Hebei Province

作　　者：王云静 陈超 崔伟[3] 张福祥 WANG Yun-jing;CHEN Chao;CUI Wei;ZHANG Fu-xiang(Hebei Key Laboratory of Strategic Critical Mineral Resources,Shijiazhuang 050031,China;Hebei GEO University,Shijiazhuang 050031,China;No.2 Geological Brigade,Hebei Bureau of Geology and Mineral Resources,Tangshan 063000,China)

机构地区：[1]河北省战略性关键矿产资源重点实验室,河北石家庄050031 [2]河北地质大学地球科学学院,河北石家庄050031 [3]河北省地矿局第二地质大队,河北唐山063000

出　　处：《河北地质大学学报》2022年第6期1-8,共8页Journal of Hebei Geo University

基　　金：河北地矿局地质科技项目(13000021LCCGAV5OZDGAS)。

摘　　要：彭庄铍矿位于冀东幔枝构造核部,其围岩主要为太古宇迁西群,区内矿产资源较为丰富,以金(铜)、BIF型铁矿为主,尚未发现品位良好、具有开采价值的铍矿床。为研究彭庄铍矿的成岩、成矿时代,重点对含绿柱石角砾岩内的锆石进行了形态学特征及U-Pb同位素测年分析。结果表明,锆石形态主要为它形浑圆状或次浑圆状,少数为短柱状。多数锆石震荡环带清晰,少数具有明显的核边结构,推测为继承锆石。Th/U比值大多大于0.1,判断锆石主要为岩浆成因锆石。U-Pb数据显示,锆石年龄主要集中在(2502±9~2512±19)Ma之间,年龄数据在年龄谐和图中基本位于谐和曲线的下方,显示存在有明显的放射性铅丢失。其年龄数据所构成的不一致线与谐和曲线的上交点年龄为(2515.5±9)Ma,代表了本区迁西群的成岩年龄,从而反映出成矿年龄小于(2515.5±9)Ma。The beryllium deposit of Pengzhuang in the core of mantle branch structure in eastern Hebei province.Its surrounding rocks are mainly Qianxi Group rocks of Archaeozoic.The area is rich in mineral resources,mainly gold(copper)and Banded Iron Formation iron ores,and no beryllium deposit with good grade and mining value has been found.In order to study the petrogenesis and mineralization age of Pengzhuang beryllium deposit,this paper focuses the zirons from green beryl breccias with analysis of Cathodoluminescence image and U-Pb ages.The results show that the morphology of zircons are mainly in its shape of xenomorphic round or sub round,and a few are short columnar.Most of the zircon oscillation bands are clear,and a few have core-periphery structure,which is speculated to be inherited zircon.Th/U ratios are mostly greater than 0.1,indicating that zircons are mainly magmatic zircons.U-Pb data show that the zircons age are mainly concentrated in the range of(2502±9~2512±19)Ma,and the age data are basically located below the harmonic curve in the age harmonic diagram,indicating that there is a significant loss of radioactive lead.The upper intersection age of the inconsistent line and the harmonic curve formed by the age data is(2515.5±9)Ma,representing the diagenetic age of the Qianxi Group in this area,which reflects that the metallogenic age is less than(2515.5±9)Ma.

关 键 词：彭庄铍矿 锆石 U-PB年龄 幔枝构造 迁西群 

分 类 号：P571[天文地球—矿物学]