Deciphering the early Archaean crustal history in the Kaapvaal and Zimbabwe cratons

破译卡普瓦尔和津巴布韦克拉通的早期太古宙地壳历史

• 批准号: 277088755
• 负责人: Professor Dr. Alfred Kröner (†)
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/277088755?language=en
• 关键词: Deciphering; early; Archaean; crustal; history

This project will investigate the oldest crustal components in two poorly known areas of the Zimbabwe and eastern Kaapvaal cratons, using field investigations, single zircon dating, geochemistry, as well as Hf and Nd isotopic systems. In central Zimbabwe, our preliminary work has identified several granitoid gneisses with zircon ages >3.6 Ga, and our aim is to understand the igneous, structural and metamorphic history of the terranes in which these rocks occur. In the eastern Kaapvaal craton, within a gneiss terrane of central Swaziland, we shall investigate an Archaean sequence of granulite-facies supracrustal rocks containing detrital zircons >3.6 Ga as well as the surrounding granitoid gneisses in which we also expect very ancient crustal components, The aim is to identify the source area of the ancient zircons and to understand the history of this ancient terrane in relation to the Ancient Gneiss Complex of Swaziland and the neighbouring Barberton Greenstone Belt and other parts of the Kaapvaal craton. Overall, this project is a contribution to understand early Archaean crustal evolution, and close cooperation with other SPP1833 projects dealing with southern Africa is envisaged.

该项目将利用现场调查、单锆石测年、地球化学以及铪和钕同位素系统，研究津巴布韦和卡普瓦尔克拉通东部两个鲜为人知的地区最古老的地壳成分。在津巴布韦中部，我们的初步工作已经识别出一些锆石年龄>3.6 Ga的花岗岩片麻岩，我们的目的是了解这些岩石所在地体的火成岩、结构和变质历史。在卡普瓦尔克拉通东部，斯威士兰中部的片麻岩地体中，我们将研究太古宙序列的麻粒岩相表壳岩石，其中含有碎屑锆石 > 3.6 Ga 以及周围的花岗岩片麻岩，其中我们也预期有非常古老的地壳成分，目的是确定古代锆石的来源区域并了解该古代地体与古代片麻岩杂岩的关系的历史斯威士兰和邻近的巴伯顿绿岩带以及卡普瓦尔克拉通的其他部分。总体而言，该项目对了解早期太古宙地壳演化做出了贡献，并设想与其他涉及南部非洲的 SPP1833 项目密切合作。