赞比亚东北部卡萨马-陇都地区碎屑锆石裂变径迹年代学特征

本文利用锆石裂变径迹方法探讨了班韦乌卢地块自泛非构造运动以来的主要构造演化时间。赞比亚东北部卡萨马-陇都地区位于班韦乌卢地块中东部。班韦乌卢地块受到其东北部的古元古代乌本迪构造带、东南部的中元古代伊鲁米德构造带、西南部泛非期卢弗里安构造带及西北部的中元古代基巴拉构造带的综合影响，其主要由基底和沉积盖层两部分组成。为研究卡萨马-陇都地区的地质特征和构造活动，本文从沉积盖层中姆波罗科索群的姆巴拉组和卡萨马群中的下卡萨马组中采集多个新鲜的岩石样品，并获得4件碎屑锆石的裂变径迹分析结果。4件锆石样品的年龄变化在（482±42）~（351±32）Ma之间，具有488~441 Ma和375~293 Ma两个年龄组，分别对应的主要时代为奥陶纪和石炭纪。对比邻区卢弗里安构造带、赞比西构造带、达马拉构造带和马拉维湖等地区已有的年龄数据可知，非洲中南部地区奥陶纪和石炭纪的两期构造活动涉及范围广，且班韦乌卢地块内的构造活动可能与后期冈瓦纳古陆块的解体事件有关。班韦乌卢地块地区研究程度很低，此次研究成果可为今后在该地区的深入研究提供重要参考。

Detrital Zircon Fission Track Thermochronology in Kasama—Nondo,Northeastern Zambia

The main tectonic evolution time of the Bangweulu Block since the Pan African tectonic activities was studied in this paper according to the zircon fission track method. The Kasama—Nondo is located at mid-eastern Bangweulu Block of northeastern Zambia. Bangweulu Block which is mainly composed of basement and sedimentary rocks was comprehensively affected by northeastern Paleoproterozoic Ubendian Belt, southeastern Mesoproterozoic Irumide Belt, southwestern Pan-African Lufulian Belt and northwestern Mesoproterozoic Kibaran Belt. In order to study the geological characteristics and tectonic activities in Kasama—Nondo, some fresh rock samples from Mbala Formation of Mporokoso Group and lower Kasama Formation of Kasama Group were took and the 4 detrital zircon fission track ages are between (482±42) Ma and (351±32) Ma. The ages might be divided into two groups, i.e. 488-441 Ma and 375-293 Ma, which respectively correspond to the main periods of the Ordovician and Carboniferous. Compared with the ages from Lufulian Belt, Zambezi Belt, Damara Belt and Malawi Lake area and so on, the tectonic activities of Ordovician and Carboniferous in mid-southern Africa involve wide area and the tectonic activities of Bangweulu Block may pave the way for the later disintegration of Gondwana Block. Few data on Bangweulu Block are available and the results can provide important information for the future work in the Kasama—Nondo.