摘要
武当群主要分布在南秦岭武当地块中部,下部为变火山岩组,上部为变沉积岩组。目前认为上部变沉积岩组成岩年龄为1000—1200Ma,属中元古代。从上部变沉积岩组凝灰岩夹层中获得5颗锆石进行了U-Pb法年龄测定,结果显示时代为(744±36)Ma,结合古生物及地层研究成果,认为测定的这组年龄值代表了武当岩群上部变沉积岩组的成岩时间为南华纪。
The Wudang Group is mainly distributed in the center of the Wudang Block of southern Qinling Mountian. This group is composed of meta-sedimentary rocks （above） and meta-volcanic rocks （below）. The forming age of the meta-sedimentary rocks was presently considered to be between 1000 and 1200 Ma. Five zircon grains were collected from the tuff sandwich in the meta-sedimentary rocks. U-Pb dating of these grain zircons shows that the age of the tuff sandwich is （744±36）Ma, different from the age we pre- vious suggested. The authors argue that the zircon U-Pb dating result is credible and the （744±36）Ma should represent the forming age of the meta-sedimentary rocks in the upper part of the Wudang Group. Hence, the grain-zircon U-Pb dating constrains the meta-sediment rocks to be in the Nanhuan, Cryogenian Period.
出处
《地层学杂志》
CSCD
北大核心
2006年第1期60-63,共4页
Journal of Stratigraphy
基金
鄂西北地质矿产调查所1/5万<大木厂幅>
<老营仓幅>联测区域地质调查成果。
关键词
武当群
变沉积岩组
单锆石U—Pb年龄
南华纪
湖北
Wudang group, meta-sedimentary rocks, zircon U-Pb dating, Nanhuan, Cryogenian Period,Hubei provience
