| 京津地区长城系下伏变质岩系变质年龄及长城系底界年龄的厘定 |
| |
| 引用本文： | 王松山,桑海清,裘冀,陈孟莪,李明荣.京津地区长城系下伏变质岩系变质年龄及长城系底界年龄的厘定[J].地质科学,1995,30(4):348-354. |
| |
| 作者姓名： | 王松山 桑海清 裘冀 陈孟莪 李明荣 |
| |
| 作者单位： | 中国科学院地质研究所 北京 100029 |
| |
| 摘 要： | 长城系属中元古宇底部,其底界年龄一直存在争议。国内发表的数据在2000-1640Ma之间。通过分析以往数据,并据近年新资料,认为长城系底界年龄划在(1700±20)Ma是比较合理的。
|
| 关 键 词： | 长城系 常州沟组 底界年龄 |
| 收稿时间： | 1993-05-28 |
| 修稿时间： | 1993-05-28; |
THE METAMORPHIC AGE OF PRE-CHANGCHENG SYSTEM IN BEIJING-TIANJIN AREA AND A DISCUSSION ABOUT THE LOWER LIMIT AGE OF CHANGCHENG SYSTEM |
| |
| Wang Songshan, Sang Haiqing ,Qiu Ji ,Chen Menge ,Li Mingrong.THE METAMORPHIC AGE OF PRE-CHANGCHENG SYSTEM IN BEIJING-TIANJIN AREA AND A DISCUSSION ABOUT THE LOWER LIMIT AGE OF CHANGCHENG SYSTEM[J].Chinese Journal of Geology,1995,30(4):348-354. |
| |
| Authors: | Wang Songshan Sang Haiqing Qiu Ji Chen Menge Li Mingrong |
| |
| Institution: | Institute of Geology, Chinese Academy of Sciences Beijing 100029 |
| |
| Abstract: | The Middle-Upper Proterozoic Section of Jixian is well known at home and abroad. The section contains four systems with the Changcheng System as the lowerest one. The Changzhougou Formation belonging to the Changcheng System is composed of conglomerate, feldsparthic sandstone and sandstone.At present, the lower limit age of Changcheng System is largely diversified from 2000 Ma to 1800 Ma reported by the different laboratories. One of the main reasons responsible for the discrepancy may be the specimen of whole rock of shale used for Pb-Pb isochron dating.The biotite seperated from metamorphic rock belonging to Pre-Changcheng System has been dated by 40Ar/39Ar method and a plateau age of 1782?3 Ma was obtained, which means that the lower limit age of Changcheng System should be younger than this age. Based on the recently reported data the 40Ar/39Ar isochron age of vien quartz grayal from Changzhougou Formation is 1744?97 Ma, and the falling age of cosmic dust from middle-upper part of the Changzhougou Formation is 1670?17 Ma by 40Ar/39Ar dating. Summing up what is mentioned above it can be concluded that the age of the bottom of the Changcheng System may be about 1700?20 Ma. |
| |
| Keywords: | Changcheng System Changzhougou Formation Lower limit age |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《地质科学》浏览原始摘要信息 |
| 点击此处可从《地质科学》下载免费的PDF全文 |
|
