新疆阔尔真阔拉金矿一带火山岩形成时代及地球化学特征

THE FORMATION AGE AND GEOCHEMICAL CHARACTERISTICS OF THE VOLCANIC ROCK OF KUOERZHENKUOLA'S GOLD MINE IN XINJIANG

阔尔真阔拉金矿产于基性、中酸性火山岩及酸性次火山岩中．该套火山岩为钙碱性岩石，具低FeO、MgO、Zr、Nb及Rb／Sr,稀土总量偏低，∑REE=42．81—85．82，具正Eu异常(基性岩)和不明显负Eu异常(中性、中酸性及酸性次火山岩)．由基性应中性及酸性次火山岩，稀土总量有所增加，δEu有所降低，但中性岩至酸性次火山岩的变化规律不明显．其地球化学特征表明为岛弧环境，形成时代为早石炭世(347—343Ma)，是由亏损地幔岩经部分熔融形成．

The gold mine of kuoexzhenkuola is formed in the basic and middle-acid volcanic rock and acid subordinate volcanic rock.This group of volcanic rock is calcium-basicity rock,and it has composite of low FeO,MgO,Zr,Nb and Pb/Sr.It抯 total content of REE is low.The number of REE is 42.81~85.82, and they have positive abnormal Eu(basic rock) and no obvious abnormal Eu(middle, middle-acid and acid subordinate volcanic rock).From basic volcanic rock to acid subordinate volcanic rock,the total content of REE increase,δEu decrease ,However,the changed law from middle rock to acid Subordinate rock isn抰 obvious .Their geochemical characteristics indicates that it is island-arc environment,It抯 formed epoch is Pre-Carboniferous period (347~343 Ma),and it is formed by negnative mantle rock melted in part rock.