(1. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長沙 410083;
2. 中南大學(xué) 有色金屬成礦預(yù)測教育部重點實驗室，長沙 410083;
3. 新疆有色地質(zhì)勘查局701隊，昌吉 831100)
摘 要: Beroen位于厄瓜多爾西南大洋增生地體和原生大陸地體拼接縫合帶的東側(cè)。基于礦區(qū)圍巖和主要硫化物的硫鉛同位素特征進行分析。除磁黃鐵礦外，其他硫化物平均δ34S為0.1%，來源于深部巖漿來源硫，并有結(jié)晶基底還原硫的貢獻。圍巖及硫化物的206Pb/204Pb為18.605~19.147，207Pb/204Pb為15.621~15.694，208Pb/204Pb為38.378~38.967，放射性成因的異常鉛，經(jīng)歷3個階段，中晚白堊紀前在地幔中為均質(zhì)的非放射成因鉛;始新世時期，富集地幔巖漿源形成，并在淺地殼同化吸收Chaucha和Macuchi基底巖石的放射性鉛;在中新世礦床形成時，與淺地殼層巖漿房的熱液系統(tǒng)有關(guān)的成礦流體淋濾圍巖的放射成因鉛，在礦石礦物中更加富集地殼鉛成分。同時，Chaucha成礦區(qū)礦床的礦石礦物鉛同位素組成比圍巖和中安第斯礦床更富集放射成因鉛，這與厄瓜多爾南部中晚第三世大量中小型體積侵入體侵位有密切關(guān)系。
關(guān)鍵字: 鉛硫同位素;成礦物質(zhì)來源;淋濾;吸收;Beroen金銀礦;厄瓜多爾西南部
（1. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
3. No.701 Geological Party, Xinjiang Geoexploration Bureau for Nonferrous Metals, Changji 831100, China）
Abstract:Ecuadorian Beroen deposit locates east of the suture zone of Chaucha continental terrane with Macuchi oceanic terrane. The Pb and S isotope compositions of main sulfides and wall rocks were studied. Excluding the pyrrhotite, δ34S value average is 0.1%, suggesting that a mantle magmatic sulfur source, with the contribution of a basement biology reductive condition sulfur source. The 206Pb/204Pb is 18.605-19.147, 207Pb/204Pb is 15.621-15.694, 208Pb/204Pb is 38.378-38.967. At first, before later Cretaceous, there is the nonradiogenic lead in mantle; then on Oligocene, enriched mantle-derived magmas ascend to the lower crust, and interact with the basement rock of Macuchi and Chaucha terranes assimilating radiogenic lead; on Miocene, the ore fluids derive from the hydrothermal systems of shallow crustal magma chambers, also react and leach the radiogenic lead from wall rocks. Also the mineral deposits in Chaucha area have significantly higher 207Pb/204Pb values than that of their wall rocks and the central Andean lead province. This can be due to small volumes of parental magma emplaced at shallow crustal levels.
Key words: lead and sulfur isotope; ore-forming material origin; leach; assimilate; Beroen gold-silver deposit; Ecuadorian Southwest
