|
|||||
|
|
| 华北克拉通南缘豫西下汤地区2.3 Ga岩浆作用和1.94 Ga变质作用 | |
| 引用本文： | 黄道袤,张德会,王世炎,张毅星,董春燕,刘敦一,万渝生.华北克拉通南缘豫西下汤地区2.3 Ga岩浆作用和1.94 Ga变质作用[J].地质论评,2012,58(3):565-576. |
| 作者姓名： | 黄道袤 张德会 王世炎 张毅星 董春燕 刘敦一 万渝生 |
| 作者单位： | 1. 中国地质大学,北京,100083 2. 中国地质大学,北京,100083 3. 河南省地质调查院,郑州,450001 4. 河南省地质调查院,郑州,450001 5. 中国地质科学院地质研究所北京离子探针中心,北京,100037 6. 中国地质科学院地质研究所北京离子探针中心,北京,100037 7. 中国地质科学院地质研究所北京离子探针中心,北京,100037 |
| 基金项目： | 本文为中国地质调查局工作项目(编号 1212011120151和1212011121062)的成果。 |
| 摘 要： | 本文报道了华北克拉通南缘豫西鲁山下汤地区古元古代片麻状花岗岩和黑云角闪斜长片麻岩的全岩地球化学和锆石SHRIMP U-Pb年龄和Hf同位素组成。岩石呈包体形式存在于中元古代花岗岩中。片麻状花岗岩具深熔特征,岩浆锆石年龄为2.30Ga;岩石高SiO2和K2O,低ΣFeO、MgO和CaO,具稀土总量较高(ΣREE=165.8×10-6)、轻重稀土分离较强(La/Yb)n=37.8]及弱负铕异常(Eu/Eu*=0.76)的稀土模式;εNd(t)(t=2.30Ga)=-0.75;tDM(Nd)=2.66Ga。黑云角闪斜长片麻岩变质原岩为辉长闪长岩,捕获锆石年龄为2.25Ga;岩石低SiO2和MgO,高Al2O3和P2O5,具稀土总量高(ΣREE=373.4×10-6)、轻重稀土分离不强(La/Yb)n=9.4]及较强负铕异常(Eu/Eu*=0.44)的稀土模式;εNd(t)(t=2.25Ga)=-1.21;tDM(Nd)=2.75Ga。片麻状花岗岩和黑云角闪斜长片麻岩都记录了1.94Ga变质锆石年龄。片麻状花岗岩的岩浆锆石组成域的εHf(t)(t=2.30Ga)=-6.71～0.38,tDM1(Hf)=2627～2910Ma,tDM2(CC)(Hf)=2823～3255Ma。黑云角闪斜长片麻岩的捕获锆石组成域的εHf(t)(t=2.25Ga)=-19.58～-1.73,tDM1(Hf)=2664～3360Ma,tDM2(CC)(Hf)=2968～4011Ma。结合前人资料,得出如下结论:华北克拉通南缘豫陕晋结合部地区存在一规模较大的约2.3Ga地质体分布区;华北克拉通南缘很可能存在规模巨大的>2.7Ga基底;中部造山带与孔兹岩带具有类似的古元古代晚期构造热事件演化历史。 |
| 关 键 词： | 古元古代 华北克拉通 岩浆作用 变质作用 锆石SHRIMP定年 Hf同位素 |
Ga Magmatism and 1.94 Ga Metamorphism in the Xiatang Area, Southern Margin of the North China Craton-Evidence from Whole rock Geochemistry and Zircon Geochronology and Hf Isotope |
|
| Institution: | Evidence from Whole-rock Geochemistry and Zircon Geochronology and Hf Isotope HUANG Daomao1) , ZHANG Dehui1), WANG Shiyan2) , ZHANG Yixin2) , DONG Chunyan3) , LIU Dunyi3) , WAN Yushneg3) 1) China University of Geosciences, Beijing, 100083; 2) Regional Geological Survey, Henan Bureau of Geology and Mineral Exploration and Development, Zhengzhou , 450001; 3) Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037 |
| Abstract: | This paper reports whole-rock geochemistry and zircon geochronology and Hf isotope of gneissic granite and biotite—amphibole—plagioclase gneiss from the Xiatang area, southern margin of the North China Craton. They occur in Mesoproterozoic granite as enclaves. The gneissic granite shows anatectic features. SHRIMP dating of magmatic zircons yielded an upper intercept age of 2.30±0.02 Ga. The rock is high in SiO2 and K2O and low in ΣFeO, MgO and CaO, with a ΣREE content, (La/Yb)n and Eu/Eu values being 165.8×10-6, 37.8 and 0.76, respectively. It has εNd(t) (t=2.30 Ga) of -0.75 and tDM(Nd) of 2.66 Ga. The biotite—amphibole—plagioclase gneiss is considered to be meta-gabbroic diorite. It contains captured zircons of 2.25 Ga with no magmatic zircons having been determined. The rock is high in Al2O3 and P2O5 and low in SiO2 and MgO, showing a high ΣREE content (373.4×10-6) and low (La/Yb)n ratio (9.4) and obvious negative Eu/Eu anomaly (0.44), with εNd(t) (t=2.30 Ga) and tDM(Nd) being -1.21 and 2.75 Ga, respectively. Combined with early researches, the conclusions can be arrived at that 1) there is a huge about 2.3 Ga rock distribution area in western Henan, southern margin of the North China Craton, and 2) the Trans-North China Orogen shared similar late Paleoproteorzoic tectono-thermal evolution to the Khondalite Belt in the northwestern North China Craton. |
| Keywords: | Paleoproterozoic North China Craton magmatism metamorphism SHRIMP zircon dating Hf isotope |
| 本文献已被 CNKI 万方数据 等数据库收录！ | |
| 点击此处可从《地质论评》浏览原始摘要信息 | |
| 点击此处可从《地质论评》下载免费的PDF全文 | |