【摘要】 对内蒙中部朱日和地区的变质玄武岩进行了锆石U--Pb年代学和地球化学研究。年代学(锆石U--Pb)研究表明这套玄武岩成岩年龄为255±12 Ma;地球化学研究表明玄武岩为亚碱性拉斑玄武岩,主量元素具有高铝、低钛、贫钾、富钠的特征,微量元素亏损大离子亲石元素(如K、Ba、Rb),富集高场强元素(如Ti、U、Zr、Ta),具有E--MORB地球化学特征。结合区域地质特征,暗示朱日和地区变质玄武岩与古亚洲洋北缘中段闭合有关。更多还原

【Abstract】 Zircon U--Pb geochronology and geochemistry of metamorphic basalt in Zhurihe area of central Inner Mongolia have been studied. The geochronology (zircon U--Pb) indicates that the diagenetic age of this set of basalts is 255 ± 12 Ma. Geochemical studies show that this set of basalts is subalkaline tholeiite,and the main elements are characterized by high aluminum,low titanium,poor potassium and high sodium content. Trace elements are deficient in large ion lithophile elements,such as K,Ba,Rb,enriched in high field strength elements,such as Ti,U,Zr and Ta with E-MORB geochemical characteristics. Combined with regional geological characteristics,it is suggested that the metamorphic basalt in Zhurihe area is related to the closure of the middle segment of the northern margin of Paleo--Asia ocean.更多还原