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福建闽中地区是我国又一个新的、重要的火山岩容矿块状硫化物铅锌多金属成矿带。为查明梅仙式铅锌银矿床的金属成矿物质来源和成矿时代,本文对其中5个主要矿床进行了矿石矿物和围岩的硫、铅同位素测试和同位素地质年代学研究。结果表明,不同矿床矿石硫化物的硫同位素组成变化范围较小且平均值接近于零,δ34S介于-3.5‰~+5.6‰,平均+2.0‰,表明硫主要为岩浆来源,火山直接喷发和从容矿火山岩中淋取皆是可能的机制。大部分矿床矿石铅以放射性成因为特征(206Pb/204Pb>18.140、207Pb/204Pb>15.584、208Pb/204Pb>38.569),且矿石铅同位素值均大于围岩,指示铅可能主要是由容矿火山岩淋滤而来。根据矿床地质特征和同位素地质测年数据,厘定出两次重要的铅锌成矿作用,即中-新元古代海底火山喷流沉积同生成矿(赋矿围岩单颗粒锆石U-Pb法、Sm-Nd等时线法和40Ar-39Ar法年龄介于933~1788Ma)和燕山期岩浆热液叠加改造成矿(侵入岩锆石SHRIMPU-Pb和Rb-Sr等时线年龄为127~154Ma)。
The Fujian-Fujian region is another new and important volcanic-hosted massive sulfide lead-zinc polymetallic metallogenic belt in our country. In order to find out the metallogenic source and metallogenic age of the Meixian-type Pb-Zn-Ag deposit, the sulfur and lead isotopic measurements and isotopic geochronology of the ore minerals and surrounding rocks were carried out in five of the major deposits. The results show that the sulfide ore deposits of a different isotopic composition of sulfur and a small range of variation average value close to zero, δ34S between -3.5 ‰ ~ + 5.6 ‰, the average + 2.0 ‰, indicates that sulfur is the main source of magma, volcanic eruption and direct Drainage from volcanic rocks calmly are all possible mechanisms. Most radioactive ore lead to deposit as characterized in (206Pb / 204Pb> 18.140,207Pb / 204Pb> 15.584,208Pb / 204Pb> 38.569), and the ore lead isotope values are greater than the surrounding rock, may be indicative of lead leaching from the ore-mainly volcanic Filter it. Based on the geological characteristics of the deposit and the dating data of isotope geology, two important Pb-Zn mineralization processes were identified, namely the Mesozoic-Neoproterozoic submarine volcanic jet deposition co-occurring mine (ore-bearing single rock zircon U-Pb method , Sm-Nd isochron and 40Ar-39Ar method aged 933 ~ 1788Ma) and magmatic hydrothermal transformation superimposed mineralization (intrusive SHRIMPU-Pb zircon and Rb-Sr isochron age of 127 ~ 154Ma ).