CAJ | 학술논문

安徽庐枞盆地位于长江中下游断陷带内，地处扬子板块北缘，是长江中下游成矿带中重要的铁铜多金属成矿区和玢岩型铁矿的集中产地。庐枞盆地西北部勘探发现了大型泥河铁矿床，其硫铁矿和硬石膏矿床也达到了中大型规模，矿床中硬石膏在不同蚀变-矿化阶段均广泛发育，具有鲜明的成矿特色。深部勘探揭示庐枞盆地深部存在含石膏沉积地层（膏盐层），但目前膏盐层与成矿作用关系尚未引起研究重视。本文总结和分析了泥河铁矿床的地质地球化学特征，着重分析了膏盐层与铁矿床形成的关系，并在阐明成矿流体系统演化过程和成矿机理的基础上，提出泥河矿床的形成与三叠系膏盐层有着重要的成因关系，膏盐层是泥河铁矿床形成的重要地质条件之一。铁矿床及蚀变围岩中的大量硬石膏主要来自膏盐层；膏盐层为铁的成矿作用提供了大部分硫和矿化剂元素。在此基础上，建立了泥河铁矿床的两期成矿模式，即中晚三叠世含膏盐地层的沉积作用期（预备成矿期）和早白垩世的岩浆热液成矿期。
안휘려종분지위우장강중하유단함대내，지처양자판괴북연，시장강중하유성광대중중요적철동다금속성광구화분암형철광적집중산지。려종분지서북부감탐발현료대형니하철광상，기류철광화경석고광상야체도료중대형규모，광상중경석고재불동식변-광화계단균엄범발육，구유선명적성광특색。심부감탐게시려종분지심부존재함석고침적지층（고염층），단목전고염층여성광작용관계상미인기연구중시。본문총결화분석료니하철광상적지질지구화학특정，착중분석료고염층여철광상형성적관계，병재천명성광류체계통연화과정화성광궤리적기출상，제출니하광상적형성여삼첩계고염층유착중요적성인관계，고염층시니하철광상형성적중요지질조건지일。철광상급식변위암중적대량경석고주요래자고염층；고염층위철적성광작용제공료대부분류화광화제원소。재차기출상，건립료니하철광상적량기성광모식，즉중만삼첩세함고염지층적침적작용기（예비성광기）화조백성세적암장열액성광기。
The Lu-Zong Mesozoic volcanic Basin is located in the lower Yangtze River fault-depression zone, where is the north margin of the Yangtze Block. There are many magnetite-apitite deposits called Porphyrite iron deposits by the Chinese scientists.Nihe iron deposit located in the northwest part of Lu-Zong basin,it is a newly found large iron-sulfur-anhydrite deposit.Anhydrite is widely developed in almost each alteration-mineralization stage of Nihe deposit.Deep exploration work has revealed gypsum-bearing sedimentary rock deeper than 1800M below under the surface in the basement strata of Lu-Zong basin.However,the relationship between gypsum-salt layer and mineralization has not attracted much attention.Based on geology and geochemistry characteristics of Nihe iron deposit,the evolution process of ore-forming fluid system,the metallogenic mechanism and the characteristics of gypsum-salt layer have been discussed in this paper.The huge amount of anhydrite in iron ore bodies and altered wall rocks were mostly came from the underlying gypsum-salt layer indicated by sulfur isotope (δ34 S)and strontium isotope (87 Sr/86 Sr)i constrains.Geological and geochemical studies all show that Triassic gypsum-salt layer has played an important role in the formation of Nihe iron deposit.The gypsum-salt layer provided plenty of sulfur and mineralizing agent.Gypsum-salt layer is weak positions mechanically,which is prone to collapse and interlayer sliding between the layers when upward migration of magmatic hydrothermal invading and contacting with the gypsum-salt layer, this can provide channels for magmatic and hydrothermal emplacement and migration.On the basis of the above analysis,A two-stages of metallogenic model for Nihe deposits has been set up:the gypsum and salt sedimentation period in the middle-late Triassic (probationary period)and the magmatic hydrothermal mineralization period in early Cretaceous.