Composition of Gold and Other Elements in the Mesozoic Magmatic Rocks of the Jiaodong Peninsula and Their Implications for Gold Mineralization
The Jiaodong Peninsula is the largest gold-producing region in China,however,the sources of its substantial gold reserves remains uncertain.Analyzing the trace elements in pre-mineralization Late Jurassic Linglong-type plutons(Linglong,Kunyushan),Early Cretaceous Guojialing-type plutons(Guojialing,Congjia),syn-to post-mineralization Early Cretaceous Weideshan-type plutons,and the mafic dioritic enclaves within the latter two plutons reveals that these formations generally exhibit lower concentrations of elements such as Cu,Au,Ag,Sb,and As compared to the average values of the continental crust.Specifically,the gold content is typically below 0.5×10-9,aligning with prior test results and suggesting a depletion process of elements such as gold during magmatic evolution.Furthermore,a significant positive correlation is observed between the Cu/Ag ratio and Cu content in both Linglong-type and Weideshan-type samples.In Guojialing-type plutons and their enclaves,a positive correlation between the Cu/Ag ratio and Au content has been observed.This relationship suggests that during magma evolution,monosulfide solid solution continuously separates from the magma.Consequently,Mesozoic magmatic rocks exhibit lower Cu/Ag ratios and reduced metal content.The accumulation of these sulfides in the middle to lower crust forms an enriched source layer of gold and other elements,thereby providing ore-forming materials essential for gold mineralization in the Jiaodong region.The study also suggests that the separation of monosulfide solid solutions during magma evolution may be a common process,which could also explain why the continental crust is depleted in copper and other elements compared to the mantle.
万方数据
维普
