| 辽东三家子地区晚侏罗世花岗岩SHRIMP U-Pb年龄、Hf同位素特征及地质意义 |
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| 引用本文： | 杨凤超,宋运红,郝立波,柴鹏.辽东三家子地区晚侏罗世花岗岩SHRIMP U-Pb年龄、Hf同位素特征及地质意义[J].地质学报,2015,89(10):1773-1782. |
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| 作者姓名： | 杨凤超 宋运红 郝立波 柴鹏 |
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| 作者单位： | 吉林大学地球科学学院,沈阳地质调查中心,吉林大学地球探测科学与技术学院,中国地质科学院地质研究所 |
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| 摘 要： | 辽东岫岩三家子矿化集中区位于青城子矿化集中区以西三家子一带,属于青城子矿化带西延部分。矿区内发育以洼岭二长花岗岩为代表的晚侏罗世侵入岩,应与本地区矿化作用有密切的关系。岩体锆石SHRIMP U-Pb年龄加权平均值为162.4±1.9Ma,代表岩浆结晶年龄,应为燕山期岩浆活动产物,是华北东部侏罗世花岗岩的一部分。全岩岩石化学分析结果显示,洼岭二长花岗岩为高钾钙碱性岩浆系列,其中SiO2(72.28%~75.61%)≥56%,Al2O3(14.37%~15.06%)≥15%(极少数低于此值),MgO小于3%制,A/CNK值1.035~1.083,均大于1,具有铝过饱和型特征。微量元素数据显示亏损重稀土元素,(La/Yb)N为18.06~22.66,Eu无负异常。具有高Sr(497×10-6~574×10-6),低Y(4.56×10-6~5.61×10-6)和Yb(0.47×10-6~0.62×10-6)特征,表现为具有埃达克质亲和性的I型花岗岩。岩体εHf(0)为负值,εHf(t)为负值(-28.9~-17.5),说明洼岭岩体形成时壳源物质成分占主导地位,单阶段Hf模式年龄(TDM)平均为1714Ma,两阶段Hf模式年龄(TDMC)平均为3704Ma。综上,洼岭岩体可能形成于从中侏罗世(160Ma)开始的多板块向东亚汇聚的构造背景,可能为加厚下地壳熔融的产物,同时是埃达克岩与铜成矿有密切关系的又一佐证。
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| 关 键 词： | 辽东半岛 洼岭岩体 锆石SHRIMP U-Pb年龄 Hf同位素 过铝质I型花岗岩 |
| 收稿时间： | 2015/7/13 0:00:00 |
| 修稿时间： | 2015/9/11 0:00:00 |
Liaodong area three shijiazi late Jurassic SHRIMP U-Pb age and Hf Iostopic Characteristics of granite from Sanjiazi area in Liaodong and geological significance |
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| yangfengchao,songyunhong,haolibo and chaipeng.Liaodong area three shijiazi late Jurassic SHRIMP U-Pb age and Hf Iostopic Characteristics of granite from Sanjiazi area in Liaodong and geological significance[J].Acta Geologica Sinica,2015,89(10):1773-1782. |
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| Authors: | yangfengchao songyunhong haolibo and chaipeng |
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| Institution: | College of Earth Science, Jilin University,Shenyang Institute of Geology and Mineral Resources,College of GeoExploration Science and Technology,Institute of Geology, Chinese Academy of Geological Sciences |
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| Abstract: | Liaoning Xiuyan Sanjiazi mineralization concentration area in Qingchengzi mineralization concentrated area west of the Sanjiazi area, belonging to the western extension part of Qingchengzi mineralization belts. Within the mining area development in Waling adamellite of late Jurassic intrusive rocks, should have close relationship with local mineralization. Zircon SHRIMP U-Pb age weighted average value was 162.4 + 1.9Ma and represent magmatic crystallization age should be to Yanshanian magmatism and is part of the Jurassic granite in the eastern NCC. The whole rock chemical analysis results showed that the Waling adamellite for high-k calc alkaline magma series, which SiO2 (72.28-75.61) is more than or equal to 56%, Al2O3 (14.37-15.06) is more than or equal to 15% (very few below this value), MgO is less than 3% of, a / CNK value 1.035-1.083, were more than 1, with aluminum satiety and characteristics. Trace element data show that the loss of heavy rare earth elements (La/Yb) N is 18.06-22.66, Eu is not negative. With high Sr (497× 10-6~574 × 10-6) and low y (4.56 × 10-6~5.61 × 10-6) and Yb (0.47 × 10-6~0.62 × 10-6) in) feature and performance with adakitic affinity of I-type granite. Rock epsilon Hf (0) is negative, the epsilon Hf (t) to negative (-28.9 ~ 17.5), that Waling rock formation of crust derived material composition accounted for dominant position, single stage HF model ages (TDM) for an average of 1714Ma. Two stage HF model ages (tdmc) average 3704Ma. In summary, Waling rock formation to start from the Middle Jurassic (160mA) multi plate to the East Asian convergence of tectonic background, may is the product of melting of the crust in the thickened and adakite and copper mineralization is closely related to evidence. |
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| Keywords: | Liaodong Peninsula Waling rock zircon SHRIMP U-Pb age Hf isotope peraluminous I type granite |
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