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滇东北茂租铅锌矿床赋存于震旦系灯影组白云岩中,矿体呈似层状、脉状和不规则状,矿石主要由黄铁矿、闪锌矿、方铅矿、方解石和白云石等组成。方解石是该矿床中最为主要的脉石矿物,其形成贯穿整个成矿过程。本文选择与硫化物紧密共生的团斑状方解石为研究对象,借助等离子体质谱仪(ICP-MS),获得了5件热液方解石的稀土元素含量数据。结果显示,全部样品的总稀土元素含量较低(ΣREE=19.56×10-6~62.55×10-6),轻、重稀土元素间分异较明显[ΣLREE/ΣHREE=1.30~10.83,(La/Yb)N=2.83~31.40]。全部样品的(La/Sm)N(0.92~6.30)和(Gd/Yb)N(3.08~5.24)值表明轻稀土和重稀土元素内部分异不显著,δEu=1.87~4.27,呈明显的Eu正异常特征,而δCe=0.83~1.18,显示Ce异常特征不明显。茂租铅锌矿床中热液方解石稀土元素含量、配分模式及相关参数与赋矿围岩灯影组白云岩不同,与区域上不同时代地层沉积岩及二叠纪峨眉山玄武岩也不同,但与会泽超大型铅锌矿床中的团斑和脉状热液方解石相似,暗示茂租铅锌矿床成矿流体中的REE来源与可能会泽矿床相似。结合同标本的C-O同位素组成和Sm-Nd同位素年龄,认为茂租铅锌矿床形成于晚三叠纪(196±13 Ma),其成矿流体中的不同组分具有不同的来源,可能与川滇黔铅锌矿床属于同构造热事件的产物,与VMS、SEDEX和MVT型不同,暂归为川滇黔型。
The ore-bearing lead-zinc deposits in northeastern Yunnan occur in the Sinian Dengying Formation dolomite. The ore bodies are layered, veins and irregular in shape. The ore is mainly composed of pyrite, sphalerite, galena, calcite and Dolomite and other components. Calcite is the most important gangue mineral in this deposit, which forms throughout the mineralization process. In this paper, we selected regimental calcite closely intergrowth with sulphide as the research object, and obtained the data of REE content of 5 hydrothermal calcite by ICP-MS. The results showed that the total REE content of all the samples was relatively low (ΣREE = 19.56 × 10-6 ~ 62.55 × 10-6), and the light and heavy rare earth elements were highly distinct [ΣLREE / ΣHREE = 1.30 ~ 10.83, (La / Yb) N = 2.83 ~ 31.40]. The values of (La / Sm) N (0.92-6.30) and (Gd / Yb) N (3.08-5.24) in all the samples show that the intragranular differences of light rare earths and heavy rare earth elements are not significant, δEu = 1.87-4.27, Positive anomaly, while δCe = 0.83 ~ 1.18, indicating that the anomaly of Ce is not obvious. The REE contents, distribution patterns and related parameters of the hydrothermal calcite in the Mocie Pb-Zn deposit are different from the dolomite of the Dengde Clay Group in the ore-dressing rocks and are different from the sedimentary rocks in the different ages in the region and the Permian Emeishan basalts. However, The speckles in the lead-zinc deposits are similar to the veins of hydrothermal calcites, suggesting that the source of REEs in ore-forming fluids from the Moci Lead-Zinc deposit may be similar to that of the Tsem deposit. Combined with the CO isotopic compositions and Sm-Nd isotopic age of the same sample, it is believed that the Mauzian lead-zinc deposit was formed in the Late Triassic (196 ± 13 Ma) and has different origins in different ore-forming fluids, The Yunnan-Yunnan lead-zinc deposit belongs to the product of the same-tectonic event, which is different from that of VMS, SEDEX and MVT and temporarily belongs to Sichuan, Yunnan and Guizhou.