【摘要】 建昌盆地义县组可分为两部分:下部以巨厚的沉积层为主,自下而上称为要路沟层、罗家沟层,局部地区沉积层之下有中基性火山岩;上部(罗家沟层之上)为酸性、中酸性火山岩系夹沉积层.罗家沟层与义县-北票地区尖山沟(砖城子)层可进行生物地层学对比.对义县组上部的一件英安岩样品进行40Ar/39Ar年代学研究,获得年龄为120 Ma,应与义县地区义县组顶部火山岩(金刚山层之上)对比.建昌地区义县组顶、底均可与义县地区大致对比.更多还原

【Abstract】 The Yixian Formation in the Jianchang basin,Liaoning Province consists of a series of volcanic-sedimentary rocks,which can be divided into two members from bottom to top.The first member is composed mostly of sedimentary rocks,including Yaolugou bed(the lower) and Luojiagou bed(the upper),with intermediate-basic volcanic rocks at the bottom of the member.The second member is mainly acid and intermediate volcanic rocks with clastic rocks.Biostratigraphically,the Luojiagou bed may be correlated to the Jianshangou(Zhuanchengzi) bed of Yixian Formation in Yixian-Beipiao area.The 40Ar/39Ar stepwise heating dating of the dacite sample at the upper part of the Yixian Formation in Jianchang basin yields an age of 120 Ma,which agrees with previous results obtained by K-Ar,Ar-Ar and U-Pb methods for the top of volcanic rocks of the Yixian Formation in the Yixian area.更多还原