Zircon chemistry and new laser ablation U-Pb ages for uraniferous granitoids in SW Cameroon

来源 :地球化学学报(英文版) | 被引量 : 0次 | 上传用户:aini826611
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The Ekomedion two-mica granite,southwest Cameroon,has potential for uranium and molybdenum mineralization.Here,we present LA-ICP-MS U-Pb ages,Lu-Hf isotope characteristics,trace element concentrations and Ti-geothermometry of zircon from this granite hosting U-Mo mineralization in pegmatitic pods.The majority of zircon are CL-dark though some CL-bright cores were also identified.U-Pb zircon age data range from 121 ± 3 to 743 ± 11 Ma with only 5 of 34 ages being near concordant.The concordant mean age of 603 ± 12 Ma is similar to ages of granitic intrusions along the Central African Shear Zone in Cameroon.Apparent ages with mean of 261 ± 6 Ma reveal open system behavior with respect to Pb and/or U.Zircon εHfi values range from-20.3 to -0.3.This implies that U-Mo was remobilized during partial melting of the surrounding gneiss.Zircon Th/U > 0.1 as well as an increasing Hf with decreasing Th/U indicates that fractional crystallization was the main factor that controlled U-Mo mineralization in pegmatitic pods.Y and Y/Ho ratios cluster from 29 to 33 close to the chondritic ratio of 28 and indicate fractionation of Y and Ho with low F contents during the earliest stages of crystallization.Late stage accumulation of F-rich magmatic-hydrothermal fluids impacted U-Mo mineralization as a ligand.Zircon contains a prominent negative Eu anomaly pointing to a fractionating system rich in plagioclase.Calculated Ti-in-zircon temperatures span 672 ℃ to 1232 ℃ with the temperatures at the high end reflecting interference from mineral inclusions in the zircon grains while the lower temperature values are linked to crystallization.
其他文献
程控数字交换机录放音系统能够对多路话音进行实时录音,能够为用户提供准确的原始录音记录。这个应用领域的产生,最初是用于安全部门,后来逐渐在很多部门都有着广泛的应用。
新基因起源是基因组进化的一种重要方式。新基因的研究可以追溯到上个世纪90年代。Long和Langley(1993)在黑腹果蝇亚群中发现第一个新基因Jingwei,由此拉开了新基因研究的序幕
该文给出了一种利用语音压缩技术,采用普通的调制解调器,通过普通的PSTN电话线路就可以实现高速、多路的数字电话设计方案.在多通道数字电话系统中,设计目标是在通用调制解调
生物芯片技术是目前国际学术界和企业界积极研究的一项热点技术.随着信息、材料、机械、微电子等科学的广泛渗透,及其在生命科学领域中的深入发展与应用,生物芯片技术已逐渐
该文讨论的主要内容是在原有蓄电池测试仪器的基础上增加了通信功能,实现一种新的虚拟仪器和网络仪器相结合的测试仪器,文中重点讨论以太网接口和USB接口的设计.方案设计中将
该文首先介绍了甚短距离传输(VSR,Very Short Reach)这一新兴的数据传输方式.针对VSR系统标准,着重介绍了符合系统要求的,而且是基于标准集成电路工艺的光电探测器原理和结构
该文研究了具有非相邻电磁耦合的1/4波长陶瓷梳状类椭圆函数滤波器的单元结构及其设计方法.类椭圆函数滤波器结构腔与腔之间的非相邻耦合可以使滤波器的过渡带中出现有限个传
B型钠尿肽(B-type natriuretic peptide,BNP)是一种已知由心肌细胞分泌,通过激活钠尿肽受体A(natriuretic peptide receptor-A,NPR-A),从而减少心肌纤维化的生物活性肽。然而
学位
In this paper,the effect of different annealing processes on the microstructure,texture,and formability of ferritic stainless steel was studied in detail.The re
转录调控、转录后调控以及翻译后蛋白修饰等机制都参与植物的非生物胁迫响应过程。在这篇论文中,我们发现拟南芥中,介导精氨酸对称性双甲基化的蛋白精氨酸甲基转移酶SKB1是一个