摘要
北淮阳(大别山北缘)中生代火山—侵入岩带西起河南信阳东至安徽舒城,早期为偏中性和偏碱性的火山碎屑岩、熔岩及相应侵入岩,晚期出现酸性火山岩及相应侵入岩。关于该带的年代学工作前人已做了较多的研究,但所用方法仅局限于全岩K-Ar法和单矿物^(40)Ar-^(39)Ar法。本文以全岩及全岩—矿物Rb-Sr等时线法为主,辅以单矿物^(40)Ar-^(39)Ar法和单颗粒锆石U-Pb稀释法,较系统地测定了该带火山—侵入岩的时代,结果表明主期活动在130～140 Ma,晚期酸性活动在117Ma左右,基本上均属于早白垩世。
The Beihuaiyang (on the northern margin of the Dabie Mts. ) Mesozoic volcanic and intrusive rock belt, which is from Xinyang of Henan Province in the west to Shucheng of Anhui Province in the east, comprises early sub-intermediate and sub-alkaline pyroclastic rocks, lavas and intrusive counterparts and late acidic volcanic rocks and intrusive counterparts. Former researchers have made many chronological studies but the methods they used were confined to the K-Ar method for whole rocks and the ^(40)Ar-^(39)Ar method for individul minerals. Here we systematically date the volcanic and intrusive rocks of the belt mainly by way of the Rb-Sr isochron method for whole rocks or whole-rock and minerals as well as the ^(40)Ar-^(39)Ar method for individul minerals and the U-Pb dilute method for single zircon grains. The results show that the peak volcanic or intrusive activity was in the span of 130～140 Ma and the late acidic activity was around 117 Ma, both belong to the early Cretaceous.
出处
《地质论评》
CAS
CSCD
北大核心
1999年第S1期674-680,共7页
Geological Review
基金
国土资源部地质调查局科技专项(地科专96-32)
教育部博士点基金资助成果
