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| 华北克拉通北缘中段古元古代强过铝质花岗岩地球化学特征及其构造意义 | |
| 引用本文： | 钟长汀,邓晋福,武永平,毛德宝,席忠,陈博.华北克拉通北缘中段古元古代强过铝质花岗岩地球化学特征及其构造意义[J].地质通报,2006,25(3):389-397. |
| 作者姓名： | 钟长汀 邓晋福 武永平 毛德宝 席忠 陈博 |
| 作者单位： | 1. 中国地质大学地球科学与资源学院,北京,100083;中国地质调查局天津地质矿产研究所,天津,300170 2. 中国地质大学地球科学与资源学院,北京,100083 3. 内蒙古地质矿产勘察院,内蒙古,呼和浩特,010010 4. 中国地质调查局天津地质矿产研究所,天津,300170 5. 内蒙古第一地质矿产勘查开发院,内蒙古,察素齐,010100 |
| 基金项目： | 中国科学院资助项目，中国科学院资源补偿费项目 |
| 摘 要： | 华北克拉通北缘中段沿集宁-凉城-千里山一线分布着大量的强过铝质花岗岩.与一般强过铝质花岗岩相比,其SiO2含量、Al2O3/TiO2比值(小于100)、Rb/Sr比值和Rb/Ba比值低,但CaO/Na2O比值高(大于0.3).稀土元素复杂,正Eu异常、负Eu异常、Eu异常不明显均发育,大致可以分成2种类型:第一类具有中等程度轻稀土富集、重稀土平缓;第二类轻稀土特征与第一类一致,但其重稀土变化大.稀土元素特征不一致主要是由于其源岩不同.LILE(K、Rb、Ba)相对富集,HSFE(Nb、Ti、P)亏损,这种地球化学特征暗示该区强过铝质花岗岩的源区成分为杂砂岩,熔融温度较高,来源较深,其构造环境与澳大利亚拉克伦造山带一致,属高温型碰撞带,应为华北克拉通西部陆块和东北陆块古元古代碰撞峰期后岩石圈伸展的产物. |
| 关 键 词： | 强过铝质花岗岩 地球化学特征 古元古代 华北克拉通北缘中段 |
| 文章编号： | 1671-2552（2006）03-0389-09 |
| 收稿时间： | 2005-05-16 |
| 修稿时间： | 2005-12-19 |
Geochemical characteristics and tectonic significations of Paleoproterozoic strongly peraluminous granitoids in the central segment of the northern margin of the North China craton |
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| ZHONG Chang-ting,DENG Jin-fu,WU Yong-ping,MAO De-bao,XI Zhong,CHEN Bo.Geochemical characteristics and tectonic significations of Paleoproterozoic strongly peraluminous granitoids in the central segment of the northern margin of the North China craton[J].Geologcal Bulletin OF China,2006,25(3):389-397. | |
| Authors: | ZHONG Chang-ting DENG Jin-fu WU Yong-ping MAO De-bao XI Zhong CHEN Bo |
| Institution: | 1. School of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083, China; 2. Tianjin Institute of Geology and Mineral Resources, China Geological Survey,Tianjin 300170, China; 3. Inner Mongolia Institute of Geology and Min |
| Abstract: | Paleoproterozoic strongly peraluminous granitioids are distributed in large amount along the line of JiningLiangcheng-Qianlishan in the central segment of the northern margin of the North China craton. Most of them are characterized by lower SiO_2 content (<74%), Al_2O_3/TiO_2 ratio (<100), Rb/Sr ratio and Rb/Ba ratio but higher CaO/Na_2O ratio (>0.3) than normal strongly peraluminous granitoids. The REE is very complex: samples have positive, negative or normal Eu anomalies. However, two types may be distinguished based on Eu/Eu *: the first type has intermediate LREE enrichment and flat HREE patterns, and the second type has the same LREE features as the first type but shows highly varied HREE. The inconsistency of the REE features of the two types suggests that the REE inherited from different source rocks. The granitoids are relatively enriched in HFLE (such as K, Rb and Ba) and depleted in HSFE (such as Nb, Ti and P). These geochemical characteristics imply that the strongly peraluminous granitioids were sourced from graywacke with high melting temperature and deep source and that their tectonic environment was similar to that of the Lachlan orogenic belt, Australia, belonging to a high-temperature collision zone. They should be the product of the lithospheric extension after the Paleoproterozoic collision of the west block and northeast block of the North China craton. |
| Keywords: | strongly peraluminous granitoids (SPG) geochemistry Paleoproterozoic central segment of the northern margin of the North China craton |
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