Granitoid-greenstone relationships in the eastern Kaapvaal craton and implications for early crustal evolution

卡普瓦尔克拉通东部花岗岩-绿岩关系及其对早期地壳演化的影响

• 批准号: 213660822
• 负责人: Privatdozent Dr. Jörg Elis Hoffmann
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/213660822?language=en
• 关键词: Granitoid; greenstone; relationships; eastern; Kaapvaal

Following up on our project, where the early Archaean continental crustal histories of the Ancient Gneiss Complex (AGC),of Swaziland and the Itsaq Gneiss Complex (IGC) of southern West Greenland) have been studied, we now focus on the geochemistry of mafic and ultramafic rocks of the lowermost stratigraphic units of the Barberton Greenstone Belt, the ca. 3.53 Ga Theespruit and Sandspruit Formations, South Africa, as well as on greenstone inliers in the Ancient Gneiss Complex of Swaziland. The preliminary results of our first project phase hint at a felsic basement to the above greenstone sequences and older continental crust as now exposed in the AGC. Chemical signatures of mafic-ultramafic volcanic rocks possible crustal contamination may be traced using a combination of major and trace elements and Hafnium-Neodymium isotope compositions. Moreover, we plan to carry out 142Nd analyses on different rock types (gneisses, amphibolites) of the Ancient Gneiss Complex and the lithologies of the Barberton Greenstone Belt to investigate whether the oldest rocks of the Kaapvaal craton had an early differentiation history that possibly began in the Hadean, when the extinct nuclide system was still active. We shall investigate whether a possible 142Nd anomaly may have been diminished by juvenile crustal contributions with time or whether it sustained in younger magmatic rocks.

我们的项目研究了斯威士兰古片麻岩杂岩 (AGC) 和西格陵兰伊萨克片麻岩杂岩 (IGC) 的早期太古宙大陆地壳历史，我们现在重点研究镁铁质和镁铁质的地球化学。巴伯顿绿岩带最低地层单元的超镁铁质岩石，大约。 3.53 Ga Theespruit 和 Sandspruit 地层，南非，以及斯威士兰古代片麻岩杂岩的绿岩内层。我们第一阶段项目的初步结果暗示，上述绿岩序列和较古老的大陆地壳存在长英质基底，如现在在 AGC 中暴露的那样。可能的地壳污染的镁铁质-超镁铁质火山岩的化学特征可以使用主要元素和微量元素以及铪-钕同位素组合物的组合来追踪。此外，我们计划对古片麻岩杂岩的不同岩石类型（片麻岩、角闪岩）和巴伯顿绿岩带的岩性进行 142Nd 分析，以研究 Kaapvaal 克拉通最古老的岩石是否具有可能开始于冥古宙，当灭绝的核素系统仍然活跃时。我们将研究可能的 142Nd 异常是否会因年轻的地壳随时间的变化而减弱，或者是否会在较年轻的岩浆岩中持续存在。

项目成果

Archaean Crystalline Rocks of the Eastern Kaapvaal Craton

• DOI: 10.1007/978-3-319-78652-0_1
• 发表时间: 2019
• 期刊: Regional Geology Reviews
• 作者: A. Kröner;J. Hoffmann;J. Wong;H. Geng;K. Schneider;H. Xie;Jin-Hui Yang;N. Nhleko

Generation of early Archaean grey gneisses through melting of older crust in the eastern Kaapvaal craton, southern Africa

• DOI: 10.1016/j.precamres.2014.07.017
• 发表时间: 2014-12-01
• 期刊: PRECAMBRIAN RESEARCH
• 影响因子: 3.8
• 作者: Kroener, Alfred;Hoffmann, J. Elis;Yang, Jinhui
• 通讯作者: Yang, Jinhui

Coexistence of enriched and modern-like 142 Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa

南非卡普瓦尔克拉通东部太古代火成岩中丰富且现代的 142 Nd 特征共存

• DOI: 10.1016/j.epsl.2018.01.022
• 发表时间: 2018
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Schneider;Hoffmann;Münker;Kröner
• 通讯作者: Kröner

Constraining the process of Eoarchean TTG formation in the Itsaq Gneiss Complex, southern West Greenland

• DOI: 10.1016/j.epsl.2013.11.050
• 发表时间: 2014-02-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Hoffmann, J. Elis;Nagel, Thorsten J.;Rosing, Minik T.
• 通讯作者: Rosing, Minik T.

The origin of highly radiogenic Hf isotope compositions in 3.33 Ga Commondale komatiite lavas (South Africa)

• DOI: 10.1016/j.chemgeo.2016.10.010
• 发表时间: 2017-04-20
• 期刊: CHEMICAL GEOLOGY
• 影响因子: 3.9
• 作者: Hoffmann, J. Elis;Wilson, Allan H.
• 通讯作者: Wilson, Allan H.