福建政和东际金(银)矿床矿浆隐爆角砾岩成矿模型及其动力学研究  

Metallogenic model and dynamics process of ore magma of cryptoexplosive breccia type in Dongji gold(silver)deposit,Zhenghe,Fujian

作　　者：朱玉磷[1] 毛光武[1] 严卸平[1] ZHU Yulin;MAO Guangwu;YAN Xieping(Bureau of China Metallurgical Geology Bureau,Fuzhou,350007)

机构地区：[1]中国冶金地质总局二局,福州350007

出　　处：《地质论评》2021年第1期99-116,共18页Geological Review

摘　　要：本文描述政和东际金(银)矿床地质特征,建立矿床成矿模型,论证矿床物质运移动力学过程,探讨成矿物质来源。矿山经过系统的勘探和开采,将暴露于地表580~620 m的矿体直至延深到地下-200 m,均得到钻探和探硐的完整揭露。采用常规、可靠的地质论证法全面收集了第一手资料以及宏微观的岩矿鉴定及部分电子探针分析,对研究标的进行综合论述。政和东际金(银)矿床矿化角砾岩筒自上而下可分为5个相带:震裂相、震碎相、隐爆相、上部通道相及下部通道相。从矿石结构构造特征、矿体侵入围岩接触关系、角砾特征、胶结物成分等一系列现象判断,矿床为矿浆隐爆成因。源于壳幔过渡带深部中酸性岩浆熔离分异的富硅、富铁熔浆,富硅熔浆先一步上侵形成大规模的火山喷发及潜火山岩的侵入,富铁熔浆滞留于"源地",俘获硫化物液滴,储集形成混合矿浆。物理性状及运移动力学特征表明,在外驱动力作用下,矿浆沿着石英斑岩"岩浆热场通道"上侵,在古地表之下2.0~2.5 km处,石英斑岩硅帽隔挡层下聚集、隐爆、定位成矿。石英斑岩为容矿围岩,与矿床有密切的时空关系但与成因无关。深部钻探验证表明隐爆角砾岩筒尾部在石英斑岩中收敛,矿化随之结束。"矿浆隐爆"作为"隐爆角砾岩型金矿"大家族中新成员,目前尚未见报道。该新类型的发现,为中酸性岩浆熔离分异成矿理论提供了难得的实例,也将有助于中国东南沿海中生代陆相火山岩区同类型金矿的找矿工作。Objectives:This research described the geological characteristics of the Zhenghe Dongji gold(silver)deposit,established a mineralization model of the deposit,demonstrated the mechanical process of the material transport and movement of the deposit,and explored the source of ore formation.Methods:The mine has undergone systematic exploration and mining.The ore body from the surface at 580 m~620 m to-200 m underground was thoroughly exposed by drilling and exploration.Using conventional and reliable geological argumentation methods,the first-hand information has been comprehensively collected.This study also equipped with macro and micro rock and mineral identification and partial electronic probe analysis for comprehensive discussion.Results:From top to bottom,Breccia pipe of the ore deposit can be divided into 5 facies belts:fissure facies belt,shattered facies belt,cryptoexplosive facies,upper channel facies and lower channel facies.Based on a series of phenomena such as the structural characteristics of the ore,the contact relationship of the ore body intrusive surrounding rock,the characteristics of the breccia,and the composition of the cement,the deposit is the origin of the ore magma.The silicon-rich and iron-rich magma originated from the separation and differentiation of acidic magma in the deep crust—mantle transition zone.The former(silicon-rich magma)invaded upwards to form largescale volcanic eruptions and sub-volcanic intrusion,while the latter(iron-rich magma)remained in the"source"and captured the sulfide droplets.The iron-rich magma then accumulated and formed a mixed ore magma.The physical properties and the mechanical characteristics of transport and movement indicate that under the external driving force,the ore magma invaded upwards along the quartz porphyry"magma thermal field channel".Accumulation,concealed explosion,positioning and mineralization were undergone at 2.0~2.5 km below the paleosurface,under the quartz porphyry silicon cap barrier.Conclusions:The Zhenghe Dongji gold(silver)min

关 键 词：东际金矿 矿浆 隐爆 角砾岩筒 动力学过程 

分 类 号：P618.5[天文地球—矿床学]