摘要
金厂金矿区火山岩是其东南方向6km处通沟岭火山中心边部的一套英安质、流纹质火山碎屑岩和凝灰岩、熔结凝灰岩组合,归属罗圈站组。火山岩SiO2含量66.32%～75.56%,K2O+Na2O含量6.05%～8.30%,σ为0.52～2.48,属钙碱性岩系;微量元素显示火山岩强烈富集Pb,亏损Sr以及Nb、Ta和P、Ti,具有大陆地壳的性质;稀土元素为轻稀土富集的右倾型,具有弱的Eu负异常。表明火山岩岩浆为太平洋板块俯冲背景下,地壳由挤压向伸展转化并发生岩石圈拆沉,软流圈上涌熔融下地壳的产物,成岩时代可能与中国东北区域火山岩的130～110Ma一致。金厂金矿为斑岩控矿,成矿集中于120～110Ma。火山活动为成矿前岩浆活动,通沟岭火山机构提供成矿构造并提供部分Au来源。区域上寻找同时期火山机构控制的斑岩控矿系统具有重要意义。
The volcanic rocks in the Jinchang gold deposit,about 6 km southeast of the Tonggouling volcanic edifice,is a suite of dacitic and rhyollitic volcanoclastic,tuff and ignimbrite rocks with the pyroclastic flow facies and side volcanic neck facies,belonging to the Luoquanzhan Formation.In the study area,the volcanic rocks are calc-alkaline series rocks,with SiO2 content 66.32%～75.56 %,K2O＋Na2O 6.05%～8.30%,and Rotman index（σ） 0.52～2.48.Trace element analysis suggests their strong enrichment in Pb,depleted in Sr,Nb,Ta,P and Ti,consistent with continental crust characteristics.REE analysis shows they are rich in light rare earth elements and have a weak negative Eu anomaly.Rock geochemistry indicates that the volcanic magma originated from the lower crust when subduction of the Paleo-Pacific plate changed the tectonic regime from compression to extension and induced the delamination of the thickened lower crust and lithospheric mantle and consequent upwelling of the asthenosphere which triggered the volcanic eruption in 130～110Ma.Volcanic activity is a prelude of the Jinchang gold deposit metallogenesis of the porphyry type in 120～110Ma.The Tonggouling volcanic edifice supplied the ore-forming structure while the volcanic rocks are the source of partial Au.It is important to explore the porphyry ore-controlling systems that are controlled by the coeval volcanic structure in this region.
出处
《地质与勘探》
CAS
CSCD
北大核心
2011年第5期772-781,共10页
Geology and Exploration
基金
武警黄金指挥部计划内重点项目<延边-东宁成矿带"金厂式"金矿综合研究及勘查突破(HJY10-03)资助
关键词
金厂金矿
火山岩
地质特征
地球化学特征
金成矿作用
黑龙江
Jinchang gold deposit
volcanic rocks
geological characteristics
geochemical characteristics
gold mineralization
