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标题：Extensive reworking of Archaean crust within the Birimian terrane in Ghana as revealed by combined zircon U-Pb and Lu-Hf isotopes
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作者：Andreas Petersson ; Anders Scherstén ; Axel Gerdes 等
期刊名称：Geoscience Frontiers
印刷版ISSN：1674-9871
出版年度：2018
卷号：9
期号：1
页码：173-189
DOI：10.1016/j.gsf.2017.02.006
语种：English
出版社：Elsevier
摘要：AbstractLocated in the southeastern parts of the Baoulé Mossi domain of the West African Craton, the Birimian terrane in Ghana is known to consist of predominantly juvenile crust emplaced during the Eburnean orogeny. Here we present novel coupled zircon U-Pb and Lu-Hf isotope data from nine Birimian granitoids intruding different domains from northwestern, western and southeastern Ghana. Sub-chondriticɛHf-values indicating reworking of Archaean crust are recorded in zircon from both northwestern and southeastern Ghana. As a conservative estimate 71% of all analysed zircon grains spanning in age from 2220 Ma to 2130 Ma require contribution from a reworked Archaean source, contradicting the common belief that the Birimian terrane consist of predominantly juvenile crust. A minimumɛHf-value of −10.5 at 2139 Ma suggests a Palaeoarchaean to late Mseoarchaean component as the contributing ancient source. Combined with previously reported heavy zirconδ18O signatures from Birimian river zircon in Ghana, our new data suggests reworking of Archaean aged sediments during subduction initiated crustal growth in the vicinity of one, or possibly in between two Archaean aged cratons.Graphical abstractDisplay Omitted
关键词：KeywordsenBirimianBaoulé MossiArchaeanCrustal growthZircon