长江中下游斑岩-矽卡岩铜多金属矿床共伴生碲、硒资源现状和成矿规律浅析

A primary study on the current status and mineralization regularities of associated Te and Se resources in porphyry-skarn Cu polymetallic deposits in the Middle-Lower Yangtze River Valley metallogenic belt,China

斑岩-矽卡岩铜多金属矿床常伴生大量的碲、硒资源,提供了全球目前几乎所有的碲、硒产量,但碲、硒在这些矿床中的成矿规律还不清楚。长江中下游成矿带多处铜多金属矿床都伴生有硒和/或碲资源,但其资源现状、赋存状态和成矿规律的研究还较为薄弱。本文基于已有的研究资料,对长江中下游伴生碲、硒资源量进行了估算,对碲、硒的赋存状态和分布规律以及成矿规律进行了探讨。目前长江中下游已探明的伴生碲、硒资源量分别为9061 t和10574 t,相当于18个大型碲矿床、21个大型硒矿床,这些矿产资源已部分回收利用。其中九瑞矿集区的资源量最大。碲、硒主要以独立矿物形式存在,发育4种产状碲的独立矿物和2种产状硒的独立矿物,它们均形成于硫化物阶段,后者主要形成于晚硫化物阶段。根据资源量相对规模,该成矿带上的矿床类型可分为硒矿床、碲硒和硒碲矿床三种。以岩体为中心向外,碲、硒含量由低到高依次为斑岩型矿体、矽卡岩型矿体和层间交代型矿体。本文初步揭示了长江中下游成矿带碲、硒矿化的成矿规律,可为资源评价和找矿勘查提供科学依据。今后应加强对斑岩-矽卡岩铜金成矿系统中碲、硒富集机制的研究。

In porphyry-skarn copper polymetallic deposits,there are commonly large amounts of associated Te and Se resources which contributed almost all of the global current Te and Se production.However,the mineralization regularities of associated Te and Se in those deposits are poorly understood.Numerous copper polymetallic deposits in the Middle-Lower Yangtze River Valley metallogenic belt(MLYRB)contain associated Se and/or Te resources.However,researches on current status,occurrence state,and the mineralization regularity of those associated Te and Se resources are notably limited.Based on previous research data,we have estimated the amounts of associated Te and Se resources in the MLYRB and explored occurrence states,distribution regularities and mineralization regularities of those associated Te and Se.At present,the amounts of associated Te and Se resources in the MLYRB are 9,061 and 10,574 metric tons,respectively,which are equivalent to resources of 18 large Te deposits and 21 large Se deposits.A portion of these mineral resources has been recovered and utilized.Especially,the largest amounts of associated Te and Se resources are found in the Jiurui ore district.Te and Se occurred mainly in forms of independent minerals,with four types of Te minerals and two types of Se minerals in terms of the occurrence state.These independent Te and Se minerals were formed in the sulfide mineralization stages.Two types of Se minerals were mianly formed in the late sulfide mineralization stage.Based on the relative scale of resources,three types of Te and Se deposits including the selenium deposit,Te-Se deposit,and Se-Te deposit have been classified in the MLYRB.Specifically,from the center(intrusive body)to the outer zone,the Te and Se contents are generally increased from the porphyry-type ore bodies,to skarn ore bodies,to carbonate replacement-type ore bodies.This paper provides an initial insight into the mineralization regularities of Te and Se in the MLYRB.It offers a scientific basis for resource assessment and mineral exploration of Te and Se resources.It is suggested that researches on the enrichment mechanisms of Te and Se resources with in the porphyry-skarn copper-gold metallogenic system should be strengthened in the future.