CAJ | 학술논문

苏海图组火山岩发育自然铜矿化,具有从拉斑玄武岩系列向钙碱性玄武岩系列过渡的特点。依据地球化学特征,表明其 TiO2含量较低(<1%),玄武岩高的 Al2 O3含量、低的稀土含量,并且稀土元素曲线具有平缓型到轻稀土低度富集的特点。微量元素原始地幔标准化图解上,它们均富集大离子亲石因素(LILE),亏损高场强元素(HFSE),具有强的 Nb 和 Ta 的负异常,Ti 的低负异常,以及 P 和 Sm 的低正异常。Zr/Nb 值和 Sm/Nd 值接近MORB 的范围,Th/Nb 值大于0.11,Nb/Zr 值小于0.04。以上这些特征均显示出典型岛弧岩浆的特点。所以,苏海图组火山岩为火山弧火山岩,其构造背景为大陆岛弧,源区可能为被流体或沉积物交待改造的亏损地幔。
소해도조화산암발육자연동광화,구유종랍반현무암계렬향개감성현무암계렬과도적특점。의거지구화학특정,표명기 TiO2함량교저(<1%),현무암고적 Al2 O3함량、저적희토함량,병차희토원소곡선구유평완형도경희토저도부집적특점。미량원소원시지만표준화도해상,타문균부집대리자친석인소(LILE),우손고장강원소(HFSE),구유강적 Nb 화 Ta 적부이상,Ti 적저부이상,이급 P 화 Sm 적저정이상。Zr/Nb 치화 Sm/Nd 치접근MORB 적범위,Th/Nb 치대우0.11,Nb/Zr 치소우0.04。이상저사특정균현시출전형도호암장적특점。소이,소해도조화산암위화산호화산암,기구조배경위대륙도호,원구가능위피류체혹침적물교대개조적우손지만。
Native copper mineralization has been found in volcanic rocks of Suhaitu formation, with a feature of transition from tholeiite basalts to calc-alkaline basalts.Geochemistry shows that the volcanic rocks have lower TiO2 content(less than 1%),fewer Rare Earth Elements and high Al2 O3 content.In addition,their REE pattern is characterized by the weak enrichment of LREE.In the primitive mantle normalized trace element spider diagram,Suhaitu volcanic rocks are characterized by the enrichment of large ion lithophile elements,and deficit of the high field strength element. They have strongly negative anomalies in Nb and Ta, weakly negative anomalies in Ti,and weakly positive anomalies in P and Sm.Their Zr/Nb and Sm/Nd ratios are close to the range of MORB,the value of Th/Nb is larger than 0.1 1,while the Nb/Zr ratio is less than 0.04.All these characteristics mentioned above suggest that volcanic rocks of Suhaitu formation were typical volcanic arc rocks,their tectonic environment was continental island arc, and its magmas were generated by partial melting of the depleted mantle modified by fluids or sediments.