赞比亚卢弗里安弧构造带再活化的证据：锆石和磷灰石裂变径迹年代学
Reactivation of Lufilian Arc in Zambia: Zircon and Apatite Fission Track Analyses

锆石和磷灰石裂变径迹年代学对揭示构造热事件的形成及演化过程具有重要的研究意义.利用锆石和磷灰石裂变径迹测试及热史模拟探讨了卢弗里安弧构造带自泛非构造运动以来的构造热演化过程.谦比希铜矿床和恩昌加铜(钴)矿床位于卢弗里安弧铜－钴成矿带中的赞比亚境内.对采自该两个矿床中的5件新鲜岩石样品进行挑选，获得了5件锆石和4件磷灰石样品.首次获得了卢弗里安弧构造带中的裂变径迹年龄，5件锆石样品的年龄分别为 265± 22 Ma、230±10 Ma、228±9 Ma、225± 9 Ma和221±10 Ma.4件磷灰石样品的年龄分别为145±10 Ma、133±10 Ma、130±10 Ma和92±9 Ma，径迹长度介于(11.4±2.4)～(11.8±2.4) μm.从热历史模拟结果可看出，从300~260 Ma，古地温持续降低至 90 ℃ 左右；随后，缓慢降低至现今的地表温度.对比卢弗里安弧构造带、赞比西构造带和达马拉构造带中的年龄数据，研究表明非洲中南部地区二叠纪－白垩纪的构造活动是一个区域性的构造活动事件.
The fission track ages of zircon and apatite are always used to reveal tectonic activities and evolutions. Based on zircon and apatite fission track analyses and thermal evolution history, in this paper, it discusses the tectonic thermal evolution process of Lufilian arc since the Pan-African tectonic movement. The Chambishi copper and the Nchanga copper and cobalt deposits occur in the Zambian Copper belt of the Lufilian arc. Five fresh rock samples were taken from these two deposits, from which 5 zircon samples and 4 apatite samples were obtained. For the first time we obtained the fission track ages in Lufilian arc. The results are as follow: the ages from the 5 zircon analysis are 265±22Ma,230±10 Ma,228±9 Ma,225±9 Ma and 221± 10 Ma respectively and those of the 4 apatite samples are 145±10 Ma,133±10 Ma,130±10 Ma and 92±9 Ma respectively and the length is between (11.4±2.4 μm and 11.8±2.4 μm. According to the modeling results of ecological thermal evolution history, from 300 Ma to 260 Ma the paleo-geotemperature continued to decrease to about 90 ℃ and it subsequently slowed down to the present surface temperature. Comparing the ages of the Lufilian belt with the Zambezi and Damara belts, it is believed that the Permian-Jurassic tectonic activities were regional tectonic reactive events in the Central and Southern Africa