湖南沃溪Au-Sb-W矿床多期黄铁矿拉曼光谱特征及其指示意义

Raman Spectral Characteristics of Multi-Stage Pyrite in Woxi Gold Deposit,Hunan Province and Its Indicative Significance

测定沃溪金矿三期黄铁矿(Py1、Py2、Py3)特征拉曼位移(A g/cm^(-1))均值分别为378.2、370.2、380.7,指示矿床形成经历了高压-低压-高压的变化过程;特征拉曼谱峰的半高宽(FWHM/cm^(-1))均值分别为8.5、11.6、9.3,指示矿床的成矿温度经历了低温-高温-低温的变化过程。结合前人研究及区域构造演化,推断Py 1形成于晚侏罗纪挤压应力背景下,成矿流体来源于区域变质流体;Py2形成于早白垩纪拉张应力背景下,成矿流体来源于伸展环境下大规模岩浆活动产生的岩浆期后热液;Py3形成于始新世-渐新世挤压应力背景下,成矿流体来源于区域变质流体。将不同阶段黄铁矿拉曼特征与主成矿期年龄及区域构造演化结合,可进一步限定不同阶段黄铁矿形成年龄,探究矿床的形成过程,挖掘成矿信息,拓展激光拉曼光谱技术在地矿领域的应用。

This study determined the average Raman shifts(A g/cm^(-1))of pyrites in three stages,Py1,Py2,and Py3,in the Woxi gold deposit,which were 378.3,372.5,and 380.3,respectively,indicating the deposit have gone thr ough a process of high pressure,low pressure,and high pressure;The average f ull width at half maximum(FWHM/cm^(-1))of the characteristic Raman peaks fo r Py1,Py2,and Py3 were 8.6,10.8,and 9.1,suggesting that thetemperat ureof ore fluids underwent a process of low temperature,high temperature,and low temperature.Based on previous research and regional tectonic evolution hi story,it inferred that Py1 was formed under the compressional background of th e Late Jurassic,with ore fluids sourcing from regional metamorphic;Py2 was fo rmed under extensional background of the Early Cretaceous,with ore fluids orig inating from post-magmatic hydrothermal activity which associated with large-scale magmatic events in extensional environment;Py3 was formed under the comp ressional background of the Early-to Middle Eocene,with ore fluids sourcing from regional metamorphic.By integrating the Raman characteristics of pyrites with the age of the main mineralization stage and the regional tectonic evolutio n history,it is possible to constrain further the ages of pyrites formed at th e other stages,explore the formation process of deposit,extract ore-forming information,and expand the application of laser Raman spectroscopy technology in the field of geology.