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Extensive reworking of Archaean crust within the Birimian terrane in Ghana as revealed by combined zircon U-Pb and Lu-Hf isotopes

Petersson, Andreas LU ; Scherstén, Anders LU and Gerdes, Axel (2016) In Geoscience Frontiers
Abstract

Located 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-chondritic e(open) Hf-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... (More)

Located 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-chondritic e(open) Hf-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 minimum e(open) Hf-value of -10.5 at 2139 Ma suggests a Palaeoarchaean to late Mseoarchaean component as the contributing ancient source. Combined with previously reported heavy zircon δ 18O 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.

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organization
publishing date
type
Contribution to journal
publication status
in press
subject
keywords
Archaean, Baoulé Mossi, Birimian, Crustal growth, Zircon
in
Geoscience Frontiers
publisher
China University of Geosciences (Beijing) and Peking University
external identifiers
  • scopus:85017339781
ISSN
1674-9871
DOI
10.1016/j.gsf.2017.02.006
language
English
LU publication?
yes
id
5b3f77c5-af50-4256-a9a5-da57acba024d
date added to LUP
2017-05-11 09:04:56
date last changed
2017-05-11 09:04:56
@article{5b3f77c5-af50-4256-a9a5-da57acba024d,
  abstract     = {<p>Located 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-chondritic e(open) <sub>Hf</sub>-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 minimum e(open) <sub>Hf</sub>-value of -10.5 at 2139 Ma suggests a Palaeoarchaean to late Mseoarchaean component as the contributing ancient source. Combined with previously reported heavy zircon δ <sup>18</sup>O 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.</p>},
  author       = {Petersson, Andreas and Scherstén, Anders and Gerdes, Axel},
  issn         = {1674-9871},
  keyword      = {Archaean,Baoulé Mossi,Birimian,Crustal growth,Zircon},
  language     = {eng},
  month        = {05},
  publisher    = {China University of Geosciences (Beijing) and Peking University},
  series       = {Geoscience Frontiers},
  title        = {Extensive reworking of Archaean crust within the Birimian terrane in Ghana as revealed by combined zircon U-Pb and Lu-Hf isotopes},
  url          = {http://dx.doi.org/10.1016/j.gsf.2017.02.006},
  year         = {2016},
}