吉林省南部二道白河地区中元古代地层的发现及其地质意义 |
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引用本文: | 石成龙,周晓东,聂立军,周凯,孙罡.吉林省南部二道白河地区中元古代地层的发现及其地质意义[J].地球科学,2020,45(7):2441-2451. |
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作者姓名: | 石成龙 周晓东 聂立军 周凯 孙罡 |
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作者单位: | 1.中国地质科学院地质研究所, 北京 100037 |
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基金项目: | 全国陆域及海区地质图件更新与共享DD20190370 |
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摘 要: | 为了查明吉林南部是否存在中元古代地层,并探索该地区的构造演化过程,利用LA-MC-ICP-MS方法对该区碎屑岩样品进行U-Pb同位素定年以及原位Lu-Hf同位素测试.两件碎屑锆石年龄主要集中在太古代(>2.5 Ga),εHf(t)为正值(+1.5~+7.5和+1.4~+4.6),中元古代和古元古代(1.7~2.3 Ga),εHf(t)为(-5.6~+5.7和-5.4~+3.4).表明其物质来源主要为太古代结晶基底和古元古代晚期辽东-吉南造山带同碰撞的花岗岩,少量可能来源于造山带的火山岩及早期花岗岩.该套地层可能为龙岗、狼林两个微陆块经历俯冲-碰撞形成了胶-辽-吉造山/活动带后的中元古代盖层沉积.
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关 键 词: | 吉林南部 二道白河 年代学 沉积地层 碎屑锆石 |
收稿时间: | 2020-04-06 |
Discovery and Geological Significance of Mesoproterozoic Strata in Erdaobaihe Area,Southern Jilin Province |
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Abstract: | In order to find out whether Mesoproterozoic strata exist in southern Jilin, and to explore the tectonic evolution of this area. U-Pb isotope dating and in situ Lu-Hf isotope test were performed on the detrital zircon samples in this area by LA-MC-ICP-MS. The age of detrital zircon is mainly concentrated in Archean (> 2.5 Ga), εHf(t) values show positive (+1.5 to +7.5 and +1.4 to +4.6), Mesoproterozoic and Paleoproterozoic (1.7~2.3 Ga), and εHf(t) values appear positive and negative (-5.6 to +5.7 and -5.4 to +3.4). It is indicated that the material source are mainly the granites of the Archean and the Late Paleoproterozoic Liaodong-Jinan orogenic belt, and a small amount may be derived from the volcanic rocks and early granites of the orogenic belt. The set of strata may be the Middle Proterozoic caprock deposits after the subduction-collision of the two micro-continental blocks of Longgang and Langlin formed the Jiao-Liao-Ji orogenic/active belt. |
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