A large number of granitoids constitutes a giant granitic belt trending EW in the Inner Mongolia.As a representative of those intrusions,the Damiao granitoid in Siziwangqi area may serve as a natural laboratory for th...A large number of granitoids constitutes a giant granitic belt trending EW in the Inner Mongolia.As a representative of those intrusions,the Damiao granitoid in Siziwangqi area may serve as a natural laboratory for the study of genesis of granite and evolution of crust.It is mainly composed of mid-coarse grained granodiorite with abundant展开更多
文摘A large number of granitoids constitutes a giant granitic belt trending EW in the Inner Mongolia.As a representative of those intrusions,the Damiao granitoid in Siziwangqi area may serve as a natural laboratory for the study of genesis of granite and evolution of crust.It is mainly composed of mid-coarse grained granodiorite with abundant
文摘内蒙古四子王旗地区发现有一套早白垩世钾玄岩。主量元素、微量元素、稀土元素以及 Sr-Nd 同位素测试结果表明,岩石以低硅(SiO_2含量为48.11%～52.77%)、高钛(TiO_2含量为1.94%～2.77%,平均2.48%)、高钾高碱(K_2O+Na_2O 为5.32%～7.02%、K_2O/Na_2O 比值为0.48～1.10)为特征,属于钾玄岩系列。它们富集大离子亲石元素、轻稀土元素,亏损高场强元素,具有微弱的 Eu 负异常(δEu=0.81～0.98),其地球化学特征总体与洋岛玄武岩(OIB)相似。Rb/Nb、Ba/Nb、La/Nb、K/Nb 和 Zr/Nb 比值主要落在 EM I OIB 范围内。^(87)Sr/^(86)Sr 和^(143)Nd/^(144)Nd 比值分别变化在0.7063～0.7077和0.51196～0.51243之间,岩石的 Nd、Sr 同位素组成接近 EM I 地幔端元。随着ε_(Nd)的减小,P_2O_5、Rh、Sr、Ba 和 Zr 逐渐富集,表明四子王旗钾玄岩没有经历明显的地壳物质混染。利用微量元素地球化学原理,推断四子王旗钾玄岩母岩浆源于含金云母地幔橄榄岩减压低度部分熔融。根据其地球化学特征可以认为,四子王旗钾玄岩是华北板块早白垩世岩石圈减薄事件的产物。
基金the Chinese Academy of Sciences(KZCX2-EW-106),the Key Laboratory of Evolutionary Systematics of Vertebrates,CAS(2010LESV006),the Special Fund for Fossil Excavation and Preparation,CASNational Basic Research Program of China(973Program)(2012CB821900,2006CB806400)+2 种基金the National Natural Science Foundation of China(40532010,41002009,J0930007)the Basic Work Program of MST of China(2006FY120300-15)中国地质调查局"全国陆相地层划分对比及海相地层阶完善"项目(编号:1212011120142)~~
