冀北龙关石墨矿区的韧性剪切带及其控矿机理

冀北龙关石墨矿区位于娘娘庙—大庙—尚义大型韧性剪切带的南缘。经过几年的普查找矿工作,笔者认为:石墨矿区就是一条近东西向古老的韧性剪切带;是一条呈线状展布的高应变带～退化变质带。带内岩石具有强烈的韧性剪切变形特征,发育有糜棱岩化带、片理化带及剪切褶皱。韧性剪切带内强应变域与弱应变域共存,而且在空间上有规律的排列;韧性剪切变形使石墨矿质发生激发和活化,由强应变域向弱应变域富集迁移及韧性流动,使矿体产生机械的(物理的)重就位(转变);石墨矿体均赋存于韧性剪切带内,并在弱应变域中形成有工业价值的厚大矿体,因此,韧性剪切带既是导矿构造又是控矿构造。

The Ductile Shear Zone Controls the Forming of Longguan Graphite Deposit in Eastern Hebei

Longguan graphite mine in Northern Hebei is seated in the south of Niangniangmiao-Damiao-Shangyi great type ductile shear zone.After some years geological survey and prospecting work,the author considers the graphite deposit is an approximate east-west direction ancient ductile shear zone,which is a linear high strain and retrogressive metamorphic zone.The rocks in the zone possess violent ductile shear deformation characteristics and developed mylonitezation zones,schistosezation zones and shear folds.The intense strain domain and weak strain domain exists together in the ductile shear zone.In addition,they array regularly in space.The ductile shear deformation induced and motivated the graphite mineral particles,which are enriched and migrated through ductile flow from the intense strain domain to weak strain domain,and made the ore body mechanical(physical) replacement(reformation).All graphite ore bodies lay up in the ductile shear zone and they formed thick and ore bodies possessing industrial values in weak strain domain.Therefore the ductile shear zone is not only a structure of leading ore deposits,but also a structure of controlling ore deposits.