海南富文金矿床矿石、围岩及地层元素地球化学特征及地质意义

Element Geochemical Characteristics and Significance of Ore,Wall Rock and Stratum in Fuwen Gold Deposit,Hainan

海南富文金矿床位于华南褶皱系五指山褶皱带北缘,主要出露早白垩世鹿母湾组(K1l)含砾碎屑沉积岩。金矿体呈脉状和似层状赋存于鹿母湾组砂岩层间破碎带中。为进一步探讨富文金矿的成矿物质来源,对石英脉型矿石、赋矿围岩鹿母湾组碎屑沉积岩及岩浆岩进行主量、微量和稀土元素测试分析。结果显示:矿石与围岩地层、岩浆岩具有相似的微量元素变化趋势以及相似的稀土配分模式,预示着成矿与地层、岩浆岩关系密切。早白垩世石英闪长岩、细粒花岗岩和碎屑沉积岩均为矿体的形成提供了成矿物质,矿床类型为岩浆热液型金矿。

The Fuwen gold deposit is located in Fuwen County,central and northern Hainan Province,and also in the northern margin of the Wuzhishan fold belt of the South China fold system.The Early Cretaceous Lumuwan Formation(K1l)is mainly exposed in the ore district.The structure in this area is developed,the magmatic volcanic movement is more frequent,the gold mineralization points are more,and the metallogenic geological conditions are better.Geological and mineral work was carried out earlier in the area,including geophysical exploration,geochemical exploration,mineral exploration,etc.,but these works focused on the ore fabric characteristics,sulfide characteristics,ore-forming fluid characteristics and isotope date of the deposit,and the research methods of element geochemical testing of gold deposits are less involved.In order to further explore the source of ore-forming materials of Fuwen gold deposit,this paper analyzed the main,trace and rare earth elements of quartz vein type ore,clastic sedimentary rock and magmatic rock of Lumuwan formation.The chemical analysis of the main components of the clastic sedimentary rocks in Lumuwan Formation shows that the weathering and alteration of the source area are weak,which reflects that the sedimentary rocks were first deposited in the active tectonic belt,and the provenance is mainly felsic rocks.The results of chemical analysis of rare earth elements show that REE is characterized by enriched LREE,lost HREE,and right-inclined normalized curve patterns,and the standardized distribution curves of REE in each sample are basically the same.It is inferred that the ore has homology with strata and rock masses.The results of trace element chemical analysis show that the ore,Lumuwan Formation strata and rock mass(quartz diorite,fine-grained granite)are significantly lost in Ba,Nb,Sr,Hf and enriched in Rb,Th,U,Pb,Sm,and their distribution trends are similar.Comprehensive analysis shows that the formation of Fuwen gold ore body in Hainan is closely related to Lumuwan strata and rock mass.Both of them provide ore-forming materials for the formation of ore bodies,and the deposit type is a magmatic hydrothermal deposit.