【摘要】 本文报道华北克拉通北部燕辽三叉裂堑系和辽-吉拗拉谷内一系列古-中元古代富碱侵入岩的锆石U-Pb年龄。这些岩体整体呈近东西向分布,与该地区同期发育的其他非造山球斑花岗岩、斜长岩和大红裕组火山岩都形成于拉张性构造环境,并构成了一条长近千公里的迄今国内外最古老的富碱侵入岩带。该富碱侵入岩带具有东部较老(＞1．8Ga)和西部年轻(1．7Ga左右)的特点,它提供了华北克拉通在1．85～1．70Ga期间处于裂解构造格局的最好证据,丰富了全球性前寒武纪超大陆裂解的研究内容。更多还原

【Abstract】 U-Pb age data on zircons is reported for the Paleo-Mesoproterozoic alkaline-rich intrusions respectively in the Yan-l,iao triple-junction aulacogen system and in the Liao-Ji aulacogen of the Noah China Craton(NCC).These intrusives,which are approximately distributed along east-west direction,together with other anorogenic rocks in the same period,such as rapakivi granites, anorthosite and the Dahongyu formation volcanic rocks,are formed in the extensional tectonic settings.These alkaline-rich intrusions are distributed near 1000km in length and form an oldest alkaline-rich intrusion belt so far reported in the world.The beh is characteristed by older rocks(＞1.8Ga)in east end of the belt than those in west end(about 1.7Ga).The Paleo-Mesoproterozoic alkaline-rich intrusion belt is an excellent example to indicate that the Northern part of the NCC was under extending rift system during 1.85～1.70Ga,and also provide a new information for study on Precambrian supercontinent breakup.更多还原