江西宜丰县大港超大型含锂瓷石矿床地质特征及成因机制探讨   总被引：1，自引：0，他引：1  

李仁泽  周正兵  彭波  陈骏  吴建波  余会强  万建军  杨爽 《矿床地质》2020,39(6):1015-1029

大港含锂瓷石矿床产于宜丰钽铌锂稀有金属成矿带甘坊花岗岩岩体内,属典型的含锂云母碱长花岗岩型矿床。含锂瓷石矿体厚度21.62~148.88 m,其中w（Al₂O₃）为15.38%~23.97%,w（Li₂O）为0.30%~1.06%,同时伴生Rb、Cs、Ta、Nb等稀有金属。矿石矿物组成为钠长石、锂云母或锂白云母,白度达80%以上。化学组成上,表现出富硅,贫铁、镁、钛,高磷的特征;铝饱和指数A/CNK值大于1.20,Zr/Hf比值（< 12）与Nb/Ta比值（< 2）极低,表明具有高分异的过铝质S型花岗岩特性。由构造环境判别图解可知,大港含锂云母碱长花岗岩应形成于同碰撞或后碰撞早期阶段的伸展构造背景下,极低的CaO/Na₂O比值（< 0.2）,指示岩体的源区应为富黏土矿物的变质泥质岩。  相似文献   

A zone of columnar joints beneath the roof of a granitic pluton: The Okueyama granite,southwestern Japan     

Masahiro Chigira  Hironori Kato 《Island Arc》2024,33(1):e12524

Igneous rocks are fractured during cooling from magma to form cooling joints, which are typically columnar joints in volcanic rocks, while orthogonal joints are considered typical for plutonic rocks. We performed a 3D study of joint systems in a granitic batholith of the Okueyama granite in western Japan, which has its roof and its internal structures from the roof to 1000 m downward exposed. We used an unmanned aerial vehicle (UAV) to observe the joints in outcrops from various angles. Based on our study, we propose a schematic model for joint systems in a granitic pluton. A granitic pluton has zones of rock columns below the roof and next to the wall. The rock column zone below the roof is as thick as 300 m, and its higher portions form steep cliffs, probably because of increased resistance to weathering. The axes of the rock columns are nearly vertical below the roof and gently plunge next to the walls, with high intersection angles with the wall. The distribution of columnar joints near only the roof and walls suggests that the granite cooled more rapidly near the roof and walls than in the core of the pluton. When the granite was jointed by parallel joints during cooling, the rock slabs between the parallel joints near the roof and the walls are subdivided into columns with polygonal cross-sections. This suggests that the granite was fractured by parallel joints at a temperature immediately below the solidus, after which the rock slabs were subdivided into rock columns during further cooling.  相似文献   

内蒙古维拉斯托稀有金属-锡多金属矿床的成矿作用:来自花岗质岩浆结晶分异的启示   总被引：1，自引：0，他引：1  

武广  刘瑞麟  陈公正  李铁刚  李睿华  李英雷  杨飞  张彤 《岩石学报》2021,37(3):637-664

内蒙古维拉斯托稀有金属-锡多金属矿床位于大兴安岭南段西坡,是一个以锡为主,共伴生锌、钨、铜、钼、铌、钽、锂和铷的大型矿床.该矿床以发育铌、钽、铷、锂矿化有别于大兴安岭南段的其他锡多金属矿床.本文对维拉斯托地区的北大山岩体和维拉斯托岩体开展了 LA-ICP-MS锆石U-Pb定年、全岩地球化学研究和锆石Lu-Hf同位素分析...  相似文献   

花岗岩锆石U-Pb年龄与全岩Rb-Sr等时线年龄对比研究及其地球化学意义   总被引：5，自引：0，他引：5  

吴俊奇  章邦桐  凌洪飞  陈培荣 《高校地质学报》2007,13(2):272-281

对国内外32个花岗岩体的锆石U-Pb年龄与全岩Rb-Sr等时线年龄之间差值（Δt）进行的频数统计分析表明：Δt呈对称正态分布（偏度系数CSK=0.36;峰度系数CKU=2.99）;年龄差（Δt）既呈正值又有负值,其均值为2.08Ma;相对年龄差（Rt）小于5%。采用最小二乘法计算,花岗岩体锆石U-Pb年龄（tZr）对全岩Rb-Sr等时线年龄（tRb）拟合出相关系数很高（r=0.998）,回归系数接近l（α=1.003）的线性回归方程（tRb =1.003tZr +1.258）。这些统计特征表明,从总体来看,花岗岩体的Rb-Sr等时线定年测定结果与锆石U-Pb定年测定结果是一致的,花岗岩全岩Rb-Sr等时线定年方法是成熟、可信的,同时也为花岗岩锆石U-Pb年龄代表结晶年龄而不代表花岗岩侵位年龄提供了依据。  相似文献   

辽北西丰地区晚侏罗世营厂岩体LA-ICP-MS锆石U-Pb年龄及岩石地球化学特征          下载免费PDF全文

彭游博  刘文彬  赵军  姚玉健  刘锦  梁斯文 《地质找矿论丛》2022,37(3):344-353

营厂岩体分布于辽北西丰县和隆镇境内，研究结果表明，该岩体主要为似斑状二长花岗岩，锆石²⁰⁶Pb/²³⁸U年龄加权平均值为156.1 Ma±1.5 Ma，形成时代为晚侏罗世。营厂岩体w（Na₂O）/w（K₂O）平均值为1.07，属高钾钙碱性系列；里特曼指数σ平均值为2.15，属钙碱系列；铝饱和指数A/CNK平均值为1.16，A/CN平均值为1.99，属过铝型；Rb、Sr、Ba、Th、Hf含量偏高，Cr、Ni、Co、V、Rb、Zr、Nb等元素含量低，为"S"型花岗岩特征。稀土元素总量平均值为w（ΣREE）＝82.80×10^-6，w（LREE）/w（HREE）=15.76，w（La）_N/w（Yb）_N=24.32，表明其轻稀土相对富集，重稀土相对亏损，稀土配分曲线右倾。δEu=0.80，铕弱负异常，说明成因与板块运动有关，w（Sm）/w（Nd）=0.20，w（Ba）/w（Sr）=1.60，w（K）/w（Rb）=249.15，表明具有壳源性质。营厂岩体具有埃达克岩的特点，其属于受太平洋板块向欧亚板块俯冲作用的影响，在挤压环境下加厚下地壳部分熔融，从而形成活动陆缘型花岗岩。  相似文献   

Geochronology,petrogenesis and tectonic implications of the Zhongchuan granitic pluton in the Western Qinling metallogenic belt,China     

Laimin Zhu  Guowei Zhang  Tao Yang  Fei Wang  Hujun Gong 《Geological Journal》2013,48(4):310-334

The Zhongchuan district is an important component of the metallogenic belt in the Western Qinling. The Zhongchuan granite pluton occurring in the centre of the Zhongchuan metallogenic area has been poorly constrained, though the Triassic granite in Western Qinling has been well documented. In‐situ zircon U–Pb ages, Hf isotopic compositions and whole‐rock geochemical data are presented for host granite and mafic microgranular enclaves (MMES) from the Zhongchuan pluton, in order to constrain its sources, petrogenesis and tectonic setting of the pluton. The distribution of major, trace and rare earth elements apparently reflect exchange between the MMES and the host granitic rocks mainly due to interactions between coeval felsic host magma and mafic magma. The zircon U–Pb age of host granite (231.6 ± 1.5 to 235.8 ± 2.3 Ma) has overlapping uncertainty with that of the MMES (236.6 ± 1.3 Ma), establishing that the mafic and felsic magmas were coeval. The Hf isotopic composition of the MMES (ε_Hf(t) = −13.4 to 4.0) is distinct from the host granite (ε_Hf(t) = −15.7 to 0.0), indicating that both enriched subcontinental lithosphere mantle (SCLM) and crustal sources contributed to their origin. The zircons have two‐stage Hf model ages of 1064 to 1798 Ma for the host granite and 858 to 1747 Ma for the MMES. This suggests that the granitic pluton was likely derived from partial melting of a Late Mesoproterozoic crust, with subsequent interaction with the SCLM‐derived mafic magmas in tectonic affinity to the South China Block. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献