光谱学与光谱分析, 2020, 40 (8): 2479, 网络出版: 2020-12-03   

胶东焦家金矿床中黄铁矿拉曼光谱特征及其成因指示意义

Micro Raman Spectral Characteristics and Implication of Pyrite in the Jiaojia Gold Deposit, Jiaodong Area, Shandong Province, China
作者单位
1 成都理工大学地球科学学院, 四川 成都 610059
2 四川省地学核技术重点实验室, 四川 成都 610059
摘要
黄铁矿是金矿床中重要的载金矿物, 它和金矿的形成有着密切的关系, 通过对黄铁矿开展矿物学研究可以提供矿床成因和找矿勘查等有用信息, 所以对于金矿床中黄铁矿的研究具有重要的意义。 拉曼光谱是对物质分子进行结构分析和定性鉴定的微区分析技术, 近年来大量用于矿物以及包裹体研究中, 而拉曼光谱在黄铁矿方面的应用前人主要在于黄铁矿载金性的研究, 以及高温高压下对黄铁矿的分析等等。 将黄铁矿激光拉曼研究和地质岩相学观察方法相结合, 来进一步探究矿物形成环境及空间变化特征。 选取胶东焦家金矿中的黄铁矿, 通过对不同深度和蚀变带上样品的拉曼光谱特征进行研究, 探讨黄铁矿拉曼特征峰的位移以及半高宽(FWHM)变化特征及其地质意义。 测试结果表明, 黄铁矿Ag拉曼位移随深度变化呈现出正相关分布特征。 矿化带内的黄铁矿样品的谱峰半高宽(中位数)主要集中在3.3 cm-1附近。 绢云岩化带半高宽主要在3.2~5.5 cm-1, 而钾化带黄铁矿样品则位于4.1~8.4 cm-1之间。 由于处在矿化带和不同蚀变带上的黄铁矿半高宽值存在着变化, 暗示了不同蚀变带中黄铁矿结晶度和有序度存在差异。 越靠近矿化带, 黄铁矿的半高宽值越低, 其结晶度较蚀变带高。 整体样品结晶有序度的分布呈现出矿化带>绢云岩化带>钾化带的特征, 从浅部钾化带的黄铁矿到矿化带内的黄铁矿, 半高宽逐渐降低, 代表了结晶度持续变好、 有序度不断地增加, 指示黄铁矿形成的温度逐渐降低。 远离矿化带到深部钾化带, 半高宽逐渐升高, 结晶有序度降低, 暗示着矿物形成温度增高。 整体拉曼位移和半高宽数据暗示着上下对称出现的蚀变带中黄铁矿结晶度以及形成温度以矿化带为中心上下也呈现出对称性, 这和岩相学上蚀变带的分布相吻合。 因此, 拉曼光谱对于热液矿床中不同蚀变分带中黄铁矿形成压力以及温度的定性研究提供了一种有效而快捷的测试手段。
Abstract
Pyrite is one of the most common metallic minerals in gold deposits. It not only has a close relationship with the gold mineralization, but also serves as the main gold-carrier. Therefore, pyrite can provide much information for growth and forming of gold. However, previous scholars study the pyrite in gold deposits by a series of geochemistry methods, such as EPMA or SIMS, to quantify the gold content and trace elements. Nevertheless, these methods are not only highly expensive but also time-spending. Therefore, we need an efficient and reliable technology. Raman spectroscopy, more convenient and reliable, is used in materials science to identify molecules and study chemical bonding and intramolecular bonds. So, it might be regarded as an effective geological tool. Therefore, we will study the formation and structure of pyrite in different alteration zones by Raman spectrum and petrography in this paper. The Jiaojia gold deposit is located in Jiaodong area, the most important gold resources in China currently. Jiaojia gold mine is a typical altered rock type deposit, with the prominent alteration zonation and structural ore-control characteristics. The wall rock is the Linglong granite and pyrite is the main ore minerals. The wall rock alteration along the fault zone in the mining area, and the wall rock alterations are mainly composed of K-feldsparization, sericitization, pyritization. By studying the Raman spectral peak data of samples in different depths and alteration zones, we discuss the Raman shift and the half height width (FWHM) of the characteristic peak of pyrite including their geological significance. Analyzing result shows that though the Raman shift of Ag has some deviation in transforming part of different alterations, it has an obviously positive correlation with the depth roughly. Pyrite in the ore body and sericitization-zone FWHM value (median) are mainly concentrated in 3.3, 3.2~5.5 cm-1 respectively. In the K-feldspathization-halo which is located away from the ore body, FWHM value (median) is concentrated in 4.1~8.4 cm-1. We can find that the FWHM declines from K-feldspathization-halo (shallow depth) to ore body firstly, then it increases gradually to K-feldspathization-halo (deep depth). We deem that from the K-feldspathization-halo to the ore body, the crystallinity and order degree of pyrite are becoming higher and higher, and the pyrite in K-feldspathization-halo has a trend to change into low crystallinity and disorder. On the other hand, it implicates that the pyrite in different alteration zones various forming temperature. So, it is not difficult to find that the pyrite in alteration zones is forming at a higher temperature with the low crystalline degree. Pyrite in the ore body are forming at a lower temperature with the high crystalline degree. This phenomenon agrees well with the petrographic study previously. In addition, we also assume that the formation temperature of pyrite for various depths is distributed symmetrically. It fits roughly to the distribution of alteration zones.

姚畅, 宋昊, 李圻, 李娜, 张刚阳. 胶东焦家金矿床中黄铁矿拉曼光谱特征及其成因指示意义[J]. 光谱学与光谱分析, 2020, 40(8): 2479. YAO Chang, SONG Hao, LI Qi, LI Na, ZHANG Gang-yang. Micro Raman Spectral Characteristics and Implication of Pyrite in the Jiaojia Gold Deposit, Jiaodong Area, Shandong Province, China[J]. Spectroscopy and Spectral Analysis, 2020, 40(8): 2479.

本文已被 1 篇论文引用
被引统计数据来源于中国光学期刊网
引用该论文: TXT   |   EndNote

相关论文

加载中...

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!