| 许康康.班韦卢地块和伊鲁米德带区域地质及构造演化特征[J].地质与勘探,2018,54(1):69-81 |
| 班韦卢地块和伊鲁米德带区域地质及构造演化特征 |
| The regional geology and tectonic evolution of the Bangweulu block and Irumide belt in Zambia |
| 投稿时间：2017-06-10 修订日期：2017-10-30 |
| DOI：10.12134/j.dzykt.2018.01.008 |
| 中文关键词: 地层 岩浆岩 构造演化 伊鲁米德带 班韦卢地块 |
| 英文关键词: Stratigraphy, Magmatic rocks, Tectonic evolution, Irumide belt, Bangweulu block |
| 基金项目:中国地质调查局项目（编号：121201006000150014）资助 |
|
| 摘要点击次数: 1756 |
| 全文下载次数: 928 |
| 中文摘要: |
| “变质克拉通”作用为稳定克拉通的被动边缘受到陆内碰撞作用的影响而发生变质和岩浆作用。班韦卢地块位于赞比亚的东北部，被认为是坦桑尼亚克拉通或刚果克拉通的变质克拉通边缘，伊鲁米德带位于班韦卢地块的东南部，为其元古宙变质克拉通边缘。本文通过对两者的基底、地层和岩浆岩特征的系统整理研究，发现元古宙变质基底从北向南随变质作用的增强，由片岩类渐变为片麻岩类，这可能是由于两者构造层位的不同和遭受变质克拉通作用的期次不同共同造成或其中之一造成的。穆瓦超群大规模沉积作用年龄为1800Ma左右，姆波洛科索群沉积碎屑主要来源于盆地南部的变质基底，锆石年龄显示含少量太古宙地壳组分。多期次的岩浆岩具有相似的地球化学性质，其来源可能为太古宙地壳的局部熔融作用。根据地层和岩浆岩特征，可以将构造演化分为3个阶段：班韦卢地块和伊鲁米德带“变质克拉通”阶段（≥1880Ma），稳定沉积阶段（1880 Ma ~1050Ma），伊鲁米德带“变质克拉通”阶段（≤1050Ma），不同阶段地幔岩浆加入量较少，但可作为热源导致太古宙地壳多次熔融而形成元古宙地质体。 |
| 英文摘要: |
| Metacraton refers to metamorphism and magmatism in an passive margin of craton which is affected by intracontinental collision. The Bangweulu block lies in the northeast of Zambia, and is considered to be a metacratonic margin of the Tanzania craton or Congo craton. The Irumide belt is in the southeast of the Bangweulu block which is the Proterozoic metacratonic margin of the Bangweulu block. This paper summarizes the characteristics of the basements, sedimentary covers and magmatic rocks of the Bangweulu block and Irumide belt. It is found thatthe Proterozoic basement grades from schist to gneisses because of the enhancement of metamorphism from north to south, probably due to the difference between the structure horizons and/or the stages of the metamorphosis. The sedimentary age of the Muva Super-Group is about 1800Ma. The sedimentary detritus of the Mporokoso Group was mainly derived from the southern part of the basin. The ages of zircon show a small amount of Archean crust in composition. The multi-stage magmatic rocks have similar geochemical properties and their sources may be the partial melting of the Archean crust. Tectonic evolution can be divided into three stages based on the characteristics of the strata and magmatic rocks: metacratonic stage of the Bangweulu block and Irumide belt (≥1880Ma), the stable sedimentary stage(1880Ma~1050Ma) and metacratonic stage of the Irumide belt(≤1050Ma). Less mantle magma was added in different stages, which served as the heat source leading to many time of melting of the Archean crust to form the Proterozoic terrain. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
