安徽省庐枞与滁州盆地火山岩岩石学特征与Fe-Cu成矿的关系

Petrology of Volcanic rocks and its Relationship to Fe-Cu Mineralization of Luzong and Chouzhou Basin, Anhui Province

庐枞盆地与滁州盆地的火山岩岩石组合分别为钾玄岩-安粗岩-粗面岩组合和安粗岩-粗面岩组合,并分别与Fe,Cu矿有成生联系,形成于早白垩世,约130Ma。庐枞盆地与滁州盆地的火山岩组合,具明显不同的化学特征,他们分别为:①SiO2-ALK系统的碱性和亚碱性,②Peacock’s碱钙系统的碱性(A,～50.8)和钙碱性(CA,～57),③SiO2-FeO*/MgO系统中的拉斑玄武质(TH,或Fe质)和钙碱性(CA,或Mg质)。庐枞盆地火山岩母岩浆源于上地幔软流圈,滁州盆地火山岩则源于俯冲的玄武质洋壳,优先富Fe的地幔和优先富Cu的玄武岩源在局部熔融时提供多量的Fe和Cu元素被萃取进入岩浆,致使两个盆地火山岩分别具有Fe与Cu成矿专属性。它们形成于与伊佐奈崎洋俯冲有关的活动大陆边缘火山弧的内带。火山岩组合成矿专属性的讨论为区域成矿潜力评价提供重要参考。谨以此文庆贺常印佛院士80华诞。

The volcanic rock assemblages of the Luzong and Chouzhou basins are shoshnite-latite-trachyte,and latite-trachyte,respectively,which correspond to Fe and Cu mineralization,respectively.They formed in Early Cretaceous with an isotopic age of ~130Ma.The volcanic rock assemblages in two basins are very different in chemical features.① Alkaline and subalkaline in the SiO2-alk system;② shoshonitic and HKCA in the SiO2-K2O system,③ alkaline with 50.8 and Calc-alkaline with 57 of the Peacock＇s Alkali-Lime Index,（4） tholeiitic or ferric and Cala-alkaline or magnesian series in the SiO2-FeO/MgO system,respectively.The parent magma of the Luzong volcanic rocks is believed to derive from partial melting of the mantle asthenospheric materials;the volcanic rocks of the Chouzhou basin are considered to be resulted from the subducted basaltic slab.The peridotite and the basalt,as magma sources,are believed to be the key for the Fe and Cu metallogenetic attributes of the Luzong and Chouzhou volcanic rock assemblages,respectively.They formed at the inner zone of volcanic arc of the active continental margin related to the Izanagi oceanic subduction.Discussion on the metallogenetic attributes of the volcanic rock assemblages would provide some reference for the evaluation of the prospective areas.This study is dedicated to celebration of the 80th birthday of Academician Chang Yinfo.