胶东海阳所斜长角闪岩的锆石U-Pb年龄──多期变质作用对锆石不一致线年龄影响的实例 |
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引用本文:李曙光,陈移之,宋明春,张志敏,杨淳,赵敦敏.1994.胶东海阳所斜长角闪岩的锆石U-Pb年龄──多期变质作用对锆石不一致线年龄影响的实例[J].地球学报,15(1,2):37-42. |
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基金项目:国家自然科学基金 |
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中文摘要:胶东海阳所胶南群斜长角闪岩中的锆石有2类:(1)捕掳晶锆石,它给出2149 Ma的 ̄(207) Pb/ ̄(206)Pb年龄,证明该区存在有早元古基底;(2)岩浆结晶锆石,它的不一致线上下交点年龄分别为1784±11Ma和448±13 Ma。然而该锆石在晋宁期和印支期曾发生2次铅丢失事件,从而使其下文点年龄(448±13 Ma)无地质意义.其上交点年龄指示了该锆石的最小结晶时代,它表明在18亿年时该地区曾有一次玄武质火山岩事件。 |
中文关键词:锆石U-Pb定年,斜长角闪岩,胶东海阳所 |
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U-P6 ZIRCON AGES OF AMPHIBOLITE FROM THE HAIYANGSUO AREA,EASTERN SHANDONG PROVINCE──AN EXAMPLE FOR INFLUENCE OF MULTIMETAMORPHISM TO LOWER AND UPPER INTERCEPTS OF ZIRCON DISCORDIA LINE AT THE CONCORDIA CURVE |
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Abstract:There are two kind of zircons in amphibolite from the Haiyangsuo area, eastern ShandongProvince:(1)Xenocrysts,they give  ̄(207) Pb/ ̄(206)Pb age of 2149 Ma,which suggests an early proterozoicbasement in this area;(2)Magmatic euhedral zircons,they give an upper intercept age of 1784±11Ma and lower intercept age of 448±13 Ma.The lower intercept age of 448±13 Ma could be resultfrom two lead loss events during the Jinning(700-1000Ma)and Indosinian(190-245Ma)move-ments and have no geological significance.The upper intercept age indicats a low limit of crystal age ofthe zircons and suggests a basaltic volcanic event at 1.8 Ga ago in this area. |
keywords:U-Pb zircon ages amphibolite Haiyangsuo eastern Shandong Province |
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