【摘要】：冷水坑銀鉛鋅礦田位于江西省貴溪市,是我國重要的銀鉛鋅礦集區(qū)。礦田中產(chǎn)有兩類特征迥異的礦體,一類為賦存于花崗斑巖體內(nèi)的細脈浸染狀-大脈狀礦體,另一類為產(chǎn)于火山碎屑巖夾層中的塊狀硫化物礦體。然而,目前關(guān)于兩類礦體的成因及聯(lián)系還存在爭議。本文采用激光剝蝕電感耦合等離子體質(zhì)譜儀對兩類礦體中的閃鋅礦和方鉛礦進行了微區(qū)原位成分的測試,試圖根據(jù)它們的微量元素特征約束礦床的成因問題。分析結(jié)果表明,產(chǎn)于細脈浸染狀-大脈狀礦體中的閃鋅礦具有相對較高的Fe、Mn、Pb、Ag、Cu、Sb、Sn和Tl含量,而產(chǎn)于層控塊狀硫化物礦體中的閃鋅礦具有相對略高的Cd含量。兩類礦體中方鉛礦的微量元素也存在一定差別,前者具有相對較高的Ag、Sb、Sn和Au含量,而后者具有相對較高的Cd、Bi、Se和Tl。通過與國內(nèi)外不同成因類型鉛鋅礦床的綜合對比,我們發(fā)現(xiàn)冷水坑礦田的閃鋅礦具有較低的Zn/Cd比(66~131)、Cd/Fe比(0.06~0.31)和Co含量(多數(shù)10×10~(-6)),以及相對較高的Sn含量(多數(shù)1×10~(-6)),這些特征與火山成因塊狀硫化物礦床中閃鋅礦的特征十分類似,表明它們可能具有類似成因。此外,我們的研究結(jié)果表明冷水坑礦田閃鋅礦中Fe、Cd、Ag、Sb和Tl等元素主要以類質(zhì)同象的形式存在,而Cu、Pb和Sn等元素主要以顯微包裹體的形式存在。方鉛礦中的Ag、Sb、Cd、Sn和Tl等元素以類質(zhì)同象的形式存在,而Mn、Bi和Se等元素可能以顯微包裹體的形式存在。此外,基于閃鋅礦-方鉛礦共生礦物對的Cd分配系數(shù)溫度計,獲得層控塊狀硫化物礦體的形成溫度為238~246℃,而細脈浸染狀-大脈狀礦體的形成溫度略低,為209~224℃,前者閃鋅礦中相對較低的Fe和Mn含量,可能由氧逸度的影響造成。綜上所述,我們認為冷水坑礦田兩類礦體具有相同的成因機制,成礦流體和成礦物質(zhì)都主要來自深部巖漿熱液,溫度、圍巖性質(zhì)及氧逸度是控制兩類礦床金屬硫化物微量元素差別的重要因素。
[Abstract]:The Lengshuikeng silver lead zinc ore field is located in Guixi city Jiangxi Province and is an important silver lead zinc ore concentration area in China. There are two different types of orebodies in the ore field, one is the vein-disseminated and large-vein orebody in the granitic porphyry, the other is the massive sulfide orebody occurring in the intercalation of pyroclastic rocks. However, there are still disputes about the origin and connection of the two types of orebodies. In this paper, the in-situ composition of sphalerite and galena in two kinds of orebodies has been measured by laser denudation inductively coupled plasma mass spectrometer in order to limit the genesis of the deposits according to their trace element characteristics. The results show that the sphalerite occurring in the vein-disseminated and large-vein ore bodies has relatively high contents of Fe ~ (2 +) mn ~ (2 +) P _ (B) _ (B) _ (B) _ (Cu) Cu _ (+) SB _ (1) Sn and TL, while the sphalerite occurring in the stratabound massive sulphide orebodies has relatively high CD content. There are also some differences in trace elements of galena between the two types of orebodies. The former has relatively high content of Ag SbSbSn and au, while the latter has relatively high content of CdSbSe and Tl. Through comprehensive comparison with different genetic types of lead-zinc deposits at home and abroad, It is found that the sphalerite in the Lengyangkeng Orefield has a relatively low Zn/Cd ratio (66 / 131) / CD / Fe / Fe ratio (0.06 ~ 0.31) and Co content (most 10 脳 10 ~ (-6), and relatively high Sn content (most 1 脳 10 ~ (-6), which are very similar to the characteristics of zinc sphalerite in the volcanic massive sulphide deposits. This suggests that they may be of similar origin. In addition, our results show that the elements such as FebCdSb and TL in sphalerite in the cold water pit ore field mainly exist in the form of similar material, while the elements such as Cu, Pb and Sn are mainly in the form of microinclusions. In galena, the elements such as Ag SbSbCdcdnSn and TL exist in the form of metamorphic homology, while mn, Bi and se may exist in the form of microinclusions. In addition, based on the CD partition coefficient thermometer of sphalerite-galena symbiotic mineral pairs, the formation temperature of stratified massive sulphide orebodies is 238246C, while the formation temperature of vein-disseminated and large-veined orebodies is slightly lower, 2090.224 鈩，

本文編號：2153625