地质学报2024，Vol.98Issue(2)：623-635,13.DOI:10.19762/j.cnki.dizhixuebao.2023372
基于红外光谱技术的内蒙古达斯矿区蚀变地质填图及其勘查指示意义
Alteration mapping and exploration indications based on SWIR and TIR spectroscopy in Dasi,Inner Mongolia
摘要
Abstract
Dasi deposit is located in the middle of the Mesozoic Daxinganling-Yanshan volcanic belt,and it has great prospecting potential for porphyry and epithermal deposits.This area is recognized as an important metallogenic belt,characterized by extensive magmatic,volcanic,and subvolcanic activity.In our study of the Dasi deposit in Inner Mongolia,we utilized SWIR and TIR technology to measure rocks from the surface and cores.With the assistance of mineral geochemical analysis and microscope observation,we successfully completed the alteration mapping and prospecting potential prediction.The results show that:① The main altered minerals at Dasi deposit include albite,microcline,quartz,sericite,kaolinite,montmorillonite,and chlorite,along with smaller amounts of alunite,tourmaline,gypsum,and biotite.② The relationship between the identified alteration minerals through SWIR analysis and the Pb orebody shows a close association between mineralization and tourmaline,alunite,kaolinite,and sericite.Dasi deposit exhibits mineral assemblages typical of medium-sulfide epithermal deposits.③ Pb mineralization dominates the deposits,mainly occurring at shallow depths of around 300 m underground.The exposed surface shows significant denudation,and the bottom plate of the Pb orebody is composed of argillization minerals,predominantly montmorillonite and chlorite.The alteration zoning,progressing from the mineralization center outward,follows the sequence of sericitizationsericite+kaolinite(+alunite+tourmaline)→sericite+montmorillonite→montmorillonite+chlorite.The orebody is located within a sericite(kaolinite)alteration zone.④ Long-wavelength sericite indicates the presence of deep-seated thermal energy,while short-wavelength white mica reflects a combination of magmatic hydrothermal solutions and external atmospheric precipitation.Wavelength shifts at 2200 nm provide insights into the metallogenic environment,such as pH,temperature,and fluid flow.⑤ The absorption depth of sericite at 2200 nm demonstrates a positive correlation with Pb grade,as expressed by the equation y(Pbgrade)=0.1217 x(absorptiondepth)(R2=0.9178).A threshold of 10％absorption depth can differentiate between sericite and kaolinite mineral types.⑥ Combined with GIS spatial overlay analysis,we determined that the peripheral areas still hold promising prospecting potential.关键词
短波红外光谱/热红外光谱/内蒙达斯矿床/蚀变填图/Al-OH光谱特征Key words
SWIR/TIR/Dasi deposit in Inner Mongolia/alteration mapping/Al-OH spectral characteristics引用本文复制引用
李兵院,郭娜,支立佳,杨文文,谢周,王潇,魏德贤..基于红外光谱技术的内蒙古达斯矿区蚀变地质填图及其勘查指示意义[J].地质学报,2024,98(2):623-635,13.基金项目
本文为中国冶金地质总局自主勘查项目(编号中冶地[2021]CMGB-XM002)资助的成果. （编号中冶地[2021]CMGB-XM002）
