摘要
通过野外地质调查发现,北京延庆白河堡水库周边出露一完整的古火山口机构,火山口中心岩性为中性粗安岩;精准的LA-ICP-MS锆石U-Pb原位定年显示火山口中心粗安岩形成年龄为131.4±1.5Ma(2σ),代表了火山喷发的年龄;古火山口机构形成于早白垩世,火山岩在岩石地层单位上相当于张家口组;古火山口机构的火山岩可能是克拉通破坏背景下岩石圈减薄、下地壳物质部分熔融的产物。
A complete ancient crater apparatus is exposed by the Baihebu reservoir in Yanqing,Beijing.The center of the crater is composed of trachyandesite with zircon U-Pb ages of 131.4±1.5 Ma(2σ).Stratigraphically,the trachyandesite belongs to Lower Cretaceous Zhangjiakou Formation and may be the product of partial melting of the lower crust.
作者
岳晨曦
于福生
张晓明
YUE Chen-xi;YU Fu-sheng;ZHANG Xiao-ming(School of Earth Sciences,China University of Petroleum(Beijing),Beijing 102249;The Fifth Geological Team of Hebei Bureau of Geology and Mineral Resources,Tangshan Hebei 063000)
出处
《四川地质学报》
2021年第3期361-365,共5页
Acta Geologica Sichuan
