大别造山带南缘浅粒岩的锆石U－Pb年龄及其地质意义

Zircon U-Pb ages of leucoleptite on the southern margin of the Dabie Mountains and their geological implications

摘要: 提要：在大别造山带，出露大量的浅粒岩，本文就其南缘宿松岩群和与之北侧毗邻的大别岩群中的2个浅粒岩样品进行锆石Ｕ－Ｐｂ年龄测定，结果表明宿松岩群的浅粒岩形成于新元古代早期（866±48Ｍａ），大别岩群中的浅粒岩的原岩则形成于中元古代末期（1159±80Ｍａ），并受到加里东期构造热事件的影响（479±16Ｍａ）。这为宿松岩群形成时代的确定以及与大别岩群中的浅粒岩层对比提供一条重要的证据。

Abstract: Abstract: Abundant leucoleptite is exposed in the Dabie orogen. Zircon U-Pb dating of two leucoleptite samples from the Susong Group-complex on the southern margin of the orogen and its adjacent Dabie Group-complex to its north suggests that the protolith of the leucoleptite in the Susong Group-complex formed in the early Neoproterozoic (866 ± 48Ma), while that in the Dabie Group-complex at the end of the Mesoproterozoic (1159 ± 80Ma) and was reworked by a tectono-thermal event in the Caledonian (479 ± 16Ma). It furnishes important evidence for the determination of the age of the Susong Group-complex and correlation with the leucoleptite in the Dabie Group-complex