中文摘要：

报道了吉林通化地区中元古代辉绿岩墙LA-ICP-MS锆石U-Pb定年结果及地球化学特征,进而探讨了华北板块东北部中元古代辉绿岩墙形成的构造背景及其与哥伦比亚超大陆裂解事件的关系。辉绿岩中锆石呈自形,具有较高的Th/U值（0.21～1.45）,其稀土配分型式显示轻稀土（LREEs）亏损、重稀土（HREEs）富集以及正Ce异常和负Eu异常,上述特征暗示所测锆石为岩浆锆石。锆石U-Pb定年结果显示：7个分析点构成一条不一致线,上交点年龄为（1 244±28）Ma,该年龄代表了辉绿岩的形成时代,即中元古代。辉绿岩的SiO2质量分数为49.3%～49.5%,Mg#值为42.2～42.6,TFe2O3为13.6%～14.1%,属于拉斑玄武岩系列。微量元素特征显示：LREEs及大离子亲石元素（LILEs）相对富集,HREEs相对亏损,具有弱的Nb、Ta的亏损和Ti的富集,无明显Eu异常,Ba/Nb和La/Nb值分别为15.8～17.3和1.15～1.20,上述特征暗示通化地区中元古代辉绿岩来源于岩石圈地幔的部分熔融,并有软流圈组分的涉入。结合前人对华北板块北缘前寒武纪地质事件的研究成果,认为通化地区中元古代辉绿岩墙形成于强烈伸展环境,其形成与哥伦比亚超大陆的裂解有关。

英文摘要：

LA - ICP - MS zircon U - Pb age and geochemical data are presented for the Mesoproterozoic diabase from Tonghua region, Jilin Province, with the aim of constraining the Mesoproterozoic tectonic setting in the northeastern part of the North China block and its relationship with the break-up of the Columbia supercontinent. The analyzed zircons from the diabase show euhedral crystals in shape, and yield high Th/U ratios （0.21 - 1.45）. Their REE patterns are characterized by depletion in light rare earth elements （LREEs） and enrichment in heavy rare earth elements （HREEs）, as well as positive Ce anomalies and negative Eu anomalies, indicating a magma origin. Zircon U - Ph dating results exhibit that seven analyzed points constitute a discordant line, with the upper intercept age of （1 244- 28） Ma, which represent the forming age of the diabase, i. e. Mesoproterozoie.Geochemically, the samples from the diabase have SiO2 =49. 3%-49. 5%, Mg =42. 2 -42. 6, and TFe203=13. 6%-14. 1%, and belong to tholeiitic series. Their trace elements are characterized by enrichment in LREEs and large ion lithophile elements （LILEs）, and depletion in HREEs, and weakly depletion in Nb and Ta and enrichment in Ti, as well as no obvious Eu anomalies. Ba/Nb and La/Nb ratios of them are 15.8 - 17.3 and 1.15 - 1.20 respectively. Based on the above-metioned evidences, the Mesoproterozoic diabase is derived from the partial melting of lithospheric mantle with the involvement of the melts from the asthenosphere mantle. Combined with the available research on the Precambrian geological events on the northern margin of the North China block, it is suggested that the Mesoproterozoic diabase formed in a strongly extensional setting, as a result of the break-up of Columbia supercontinent.