Occurrence State and Enrichment Mechanism of Gold in Nanlü-Xinmu Gold Deposit,Shandong Province
The Nanlü-Xinmu gold deposit is a super large gold deposit since explored.In order to discuss the occurrence status and enrichment mechanism of gold,rock and ore samples were collected in this study.The ore structure,mineral composition,mineral generation sequence,mineralization stage division,and the morphology,particle size,fineness,occurrence status,and enrichment mechanism of gold were obtained by using optical thin section identification,energy spectrum,and electron probe microanalysis(EPMA)methods.The mineralization stage of Nanlü-Xinmu gold deposit can be divided into four stages,namely pyrite-quartz(I),gold-pyrite-quartz(Ⅱ),gold-quartz-polymetallic sulfide(Ⅲ)and quartz-carbonate(Ⅳ).The main mineralization stage of gold is the second and third stages.The existence modes of gold include interstitial gold(49.87%),fissure gold(42.81%),and inclusion gold(7.31%).The size of crack gold is 7～20 μm.The fineness of gold is between 886 and 943,the average fineness is 845.10,and the coefficient of variation is 11.72%.The correlation analysis results show that the most significant correlations are gold-silver and iron-sulfur.The correlation between gold and other elements is in the order of Au-Ag-Cr-Fe-S,with little correlation with Pb,Cu,Zn,etc.Pyrite is a gold bearing mineral.Gold is leached out from the ore source bed(ancient Metamorphic rock and Linglong composite rock body)and migrated as simple chlorides and complexes.Gold mineralization is concentrated in the superposition of two mineralization stages.This study provides basic data for revealing the occurrence and genesis of regional gold.
occurrence state of goldmetallogenic and enrichment mechanismmetallogenic stagegold finenessNanlü-Xinmu gold deposit
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