dc.contributor.author |
Sakyi, P.A. |
|
dc.contributor.author |
Su, B-X. |
|
dc.contributor.author |
Manu, J. |
|
dc.contributor.author |
Kwayisi, D. |
|
dc.contributor.author |
Anani, C.Y. |
|
dc.contributor.author |
Alemayehu, M. |
|
dc.contributor.author |
Malaviarachchi, S.P.K. |
|
dc.contributor.author |
Nude, P.M. |
|
dc.contributor.author |
Su, B-C. |
|
dc.date.accessioned |
2020-07-20T11:59:26Z |
|
dc.date.available |
2020-07-20T11:59:26Z |
|
dc.date.issued |
2020-03-12 |
|
dc.identifier.citation |
Sakyi PA, Su B-X, Manu J, Kwayisi D, Anani CY, Alemayehu M, Malaviarachchi SPK, Nude PM, and Su B-C. Origin and tectonic significance of the metavolcanic rocks and mafic enclaves from the Palaeoproterozoic Birimian Terrane, SE West African Craton, Ghana. Geological Magazine https://doi.org/10.1017/ S001675681900150X |
en_US |
dc.identifier.other |
https://doi.org/10.1017/S001675681900150X |
|
dc.identifier.uri |
http://ugspace.ug.edu.gh/handle/123456789/35660 |
|
dc.description |
Research Article |
en_US |
dc.description.abstract |
The Palaeoproterozoic Birimian Supergroup of the West African Craton (WAC) consists of
volcanic belts composed predominantly of basaltic and andesitic rocks and intervening sedimentary
basins composed predominantly of wackes and argillites. Mafic metavolcanic rocks
and granitoid-hosted enclaves from the Palaeoproterozoic Lawra Belt of Ghana were analysed
for geochemical and Sr–Nd isotopic data to constrain the geological evolution of the
southeastern part of the WAC. The metavolcanic rocks display mainly tholeiitic signatures,
whereas the enclaves show calc-alkaline signatures. The high SiO2 contents (48.6–68.9 wt%)
of the enclaves are suggestive of their evolved character. The high Th/Yb values of the samples
relative to that of the mantle array may indicate derivation of their respective magmas from
subduction-modified source(s). The rocks show positive εNd values of þ0.79 to þ2.86 (metavolcanic
rocks) and þ0.79 to þ1.82 (enclaves). These signatures and their Nd model ages
(TDM2) of 2.31–2.47 Ga (metavolcanic rocks) and 2.39–2.47 Ga (enclaves) suggest they were
probably derived from juvenile mantle-derived protoliths, with possible input of subducted
pre-Birimian (Archean?) rocks in their source(s). Their positive Ba–Th and negative Nb–
Ta, Zr–Hf and Ti anomalies may indicate their formation through subduction-related magmatism
consistent with an arc setting. We propose that the metavolcanic rocks and enclaves from
the Lawra Belt formed in a similar island-arc setting. We infer that the granitoids developed
through variable degrees of mixing/mingling between basic magma and granitic melt during
subduction, when blobs of basic to intermediate parental magma became trapped in the granitic
magma to form the enclaves. |
en_US |
dc.description.sponsorship |
National
Natural Science Foundation of China (Grants 41772055 and 91755205) and
State Key Laboratory of Lithospheric Evolution (Grant 201701) |
en_US |
dc.language.iso |
en |
en_US |
dc.publisher |
Geological Magazine |
en_US |
dc.relation.ispartofseries |
;2020 |
|
dc.subject |
West African Craton |
en_US |
dc.subject |
Birimian Terrane |
en_US |
dc.subject |
Lawra Belt |
en_US |
dc.subject |
Sr–Nd isotopes |
en_US |
dc.subject |
subduction |
en_US |
dc.subject |
arc setting |
en_US |
dc.title |
Origin and tectonic significance of the metavolcanic rocks and mafic enclaves from the Palaeoproterozoic Birimian Terrane, SE West African Craton, Ghana |
en_US |
dc.type |
Article |
en_US |