Cathodoluminescence characteristics and diagenetic fluids of dolomites in lower Cambrian Longwangmiao formation of central Sichuan basin

Lower Cambrian Longwangmiao formation of central Sichuan basin is one of China's important natural gas reservoirs,which was discovered in recent years.Through cathodoluminescence analysis of 46 dolomite core samples of Longwangmiao formation,in combination with Mn and Fe element analysis,it is found that dolomites in Longwangmiao formation are generally of weaker cathodoluminescence characteristic,which is related with the lower Mn content.Different dolomites with different structure types have different cathode luminance and the Fe/Mn value has the major control function on it.The atmospheric water in early diagenetic stage,the subsurface fluid in middle diagenetic stage and the atmospheric water in supergene stage have the major control function on dolomite cathodoluminescence characteristics in Longwangmiao formation.