(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長沙 410083)
摘 要: 盤龍鉛鋅礦是桂中地區(qū)典型的大型鉛鋅礦床，它位于廣西大瑤山西側(cè)鉛鋅多金屬成礦帶南段。為了確定該礦床成礦流體性質(zhì)和成礦金屬來源，作者系統(tǒng)研究了礦床的稀土元素、硫鉛同位素和流體包裹體特征。研究結(jié)果表明：礦石和圍巖的ΣREE較低，LREE富集、具有顯著的Eu正異常和弱Ce負(fù)異常；礦石的硫同位素除了3件黃鐵礦樣品δ34SV-CDT為−17.90×10−3、−21.00×10−3和−20.60×10−3, 其它硫化物的δ34SV-CDT均落在−7.10×10−3~ 7.70×10−3之間，而重晶石樣品的δ34SV-CDT較高，達(dá)17.3×10−3~29.2×10−3，硫同位素分析結(jié)果暗示成礦物質(zhì)來源于深源巖漿和泥盆紀(jì)海水的共同作用；礦石的鉛同位素206Pb/204Pb、207Pb/204Pb和208Pb/204Pb的變化范圍分別為18.376~18.438、15.763~15.852和38.763~39.060，相似的鉛同位素特征表明礦石的來源和成因是均一的、相同的，并且具有殼源的特征。噴流成礦期成礦流體均一溫度屬中−低溫(166~289 ℃) 、低鹽度(4.01%~14.07%)、低密度(0.804~0.955 g/cm3)，成礦流體屬于H2O-NaCl體系。綜合礦床地質(zhì)和地球化學(xué)特征可知，盤龍鉛鋅礦床顯著區(qū)別于MVT型鉛鋅礦，應(yīng)屬于海底噴流−沉積型鉛鋅礦。
關(guān)鍵字: 噴流−沉積；稀土元素；硫鉛同位素；鉛同位素；成礦流體；大瑤山鉛鋅多金屬成礦帶
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China；
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China）
Abstract:The Panlong lead-zinc deposit in the central region of Guangxi Province is a typical giant lead-zinc deposit, lying in the southwestern side of the Dayaoshan lead-zinc mupltimetal zone in China. The REE, S isotope, Pb isotope and fluid influsion geochemistry were discussed for understanding the source of the ore metal and the characters of ore-fluids in Panlong lead-zinc deposit. The results show that the low ΣREE and enriched LREE of the ore and wall rock pronounce the positive Eu anomaly and weak negative Ce anomaly. Most of sulfide δ34SV-CDT values range from −7.1×10−3 to 7.7×10−3, except for those of three pyrite samples with 17.9×10−3, −21×10−3 and −20.6×10−3, and those of barite samples range from 17.3×10−3 to 29.2×10−3, which indicates that the sulfur of ore is mainly derived from the mantle and the sea water. The Pb isotope analyses reveal that the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of the ore lead are 18.376−18.438, 15.763−15.852 and 38.763−39.060, respectively, which indicates that they have homogeneous, same source and geneses of Pb, and the lead shows characteristics of the upper crust lead. In sedimentary exhalative stage the ore-forming fluid is an H2O-NaCl system, with medium to low temperature (166−289 ℃), low salinity (4.01%−14.07%) and low density (0.804−0.955 g/cm3). The geological and geochemical characteristics of the deposit lead to a conclusion that the Panlong lead-zinc deposit belongs to SEDEX deposit and is notably different from MVT deposit.
Key words: exhalative-sedimentation; rare earth element; S isotope; Pb isotope; ore-forming fluid; Dayaoshan lead-zinc mupltimetal zone
