本文選題：湖南七寶山　切入點：Rb-Sr法測年　出處：《地質通報》2017年05期

【摘要】：湘東北七寶山銅多金屬礦床位于欽杭成礦帶西段,是湘東北規(guī)模最大的銅多金屬礦床。對七寶山礦床含礦石英脈中的石英礦物進行Rb-Sr同位素年齡測定,獲得的Rb-Sr等時線年齡為153.4±2.0Ma(MSWD=1.8),~(87)Sr~(86)Sr初始值為0.71849±0.00026,與區(qū)內石英斑巖形成年齡(153~155Ma)相同,說明七寶山銅多金屬礦床成因與石英斑巖體密不可分,成巖成礦年齡均在燕山期。為分析七寶山礦床成礦物質來源,對礦區(qū)內的黃鐵礦進行了S、Pb同位素分析,礦石δ~(34)S為3.24‰~4.84‰,平均值為4.198‰;巖體δ~(34)S為2.22‰~3.86‰,平均值為2.805‰。δ~(34)S值總體變化較小,巖體δ~(34)S值較礦石小,更趨近于0值,說明巖體中硫極可能源于地幔;而礦床中硫來源于主體地幔硫和少量地殼硫混熔的混合硫源。Pb同位素變化范圍也較小,礦石206Pb/~(204)Pb值變化范圍為18.315~18.396,平均值為18.359;~(207)Pb/~(204)Pb值變化范圍為15.629~15.737,平均值為15.675;~(208)Pb/~(204)Pb值變化范圍為38.376~38.856,平均值為38.609。礦化巖體數值與之相似,結果顯示,七寶山銅多金屬礦床的Pb同位素組成具有下地殼富釷(鉛)貧鈾(鉛)的特點。據此提出,礦床的成礦物質主要來自與含礦斑巖體有聯系的深部巖漿分異演化而析出的含礦氣-液流體。含礦斑巖體定位-結晶時,通過對周圍受熱地下水的對流循環(huán)作用,可以從圍巖中萃取少量成礦物質加入成礦作用。
[Abstract]:The Qibaoshan copper polymetallic deposit in northeast Hunan is located in the western section of Qinghang metallogenic belt and is the largest copper polymetallic deposit in northeast Hunan. The quartz minerals in the quartz veins of the Qibaoshan deposit are determined by Rb-Sr isotopic age. The obtained Rb-Sr isochron age is 153.4 鹵2.0 Ma, and its initial value is 0.71849 鹵0.00026, which is the same as the age of quartz porphyry formation in the area, indicating that the origin of the Qibaoshan copper polymetallic deposit is closely related to the quartz porphyry. The diagenetic and metallogenic ages are all in Yanshanian epoch. In order to analyze the source of ore-forming material in Qibaoshan deposit, the pyrite in the ore area is analyzed by Szhan-Pb isotope. The ore 未 ~ (34) N ~ (34) S is 3.24 鈥，

本文編號：1656115