TY - JOUR
T1 - Zircon Trace Element Constraints on the Evolution of the Paleoproterozoic Birimian Granitoids of the West African Craton (Ghana)
AU - Sakyi, Patrick Asamoah
AU - Su, Benxun
AU - Kwayisi, Daniel
AU - Chen, Chen
AU - Bai, Yang
AU - Alemayehu, Melesse
N1 - Publisher Copyright:
© 2017, China University of Geosciences and Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - The Paleoproterozoic Birimian granitoids of the West African Craton (WAC) in the northwestern part of Ghana, have been studied for their zircon trace elements concentrations to infer the source characteristics, origin, and magmatic evolution. The zircons in the granitoids have Th/U ratios ranging from 0.03 to 1.55, and display depleted light rare earth elements (LREE) and enriched heavy rare earth elements (HREE) contents, characterized by pronounced positive to negative anomalies of Eu (Eu/Eu*=0.14–0.98 and 1.01–6.06, respectively) and Ce (Ce/Ce*=0.08–0.98 and 1.02–116, respectively), which may imply that they were derived from both magmatic and hydrothermal sources. The geochemical plots of U/Yb vs. Y and Hf, the positive correlation between Hf and the other high field strength elements (HFSE) and high rare earth elements (REE) contents, with enrichment in Ce and depletion in Eu, indicate that the granitoids possibly formed from partial melting of the crust. The trace elements characteristics (i.e., wide range of Hf, Ce/Ce*, Th/U and Zr/Hf values) of the zircons suggest that crystallization of the magma occurred under variable oxidation states, which spanned over a longer period, implying that our data corroborate interpretations from studies of whole-rock geochemistry and geochronology on the granitoids of northwestern Ghana. This further indicates that the evolution of the Birimian granitoids in this part of the WAC occurred earlier than what had been reported in the literature.
AB - The Paleoproterozoic Birimian granitoids of the West African Craton (WAC) in the northwestern part of Ghana, have been studied for their zircon trace elements concentrations to infer the source characteristics, origin, and magmatic evolution. The zircons in the granitoids have Th/U ratios ranging from 0.03 to 1.55, and display depleted light rare earth elements (LREE) and enriched heavy rare earth elements (HREE) contents, characterized by pronounced positive to negative anomalies of Eu (Eu/Eu*=0.14–0.98 and 1.01–6.06, respectively) and Ce (Ce/Ce*=0.08–0.98 and 1.02–116, respectively), which may imply that they were derived from both magmatic and hydrothermal sources. The geochemical plots of U/Yb vs. Y and Hf, the positive correlation between Hf and the other high field strength elements (HFSE) and high rare earth elements (REE) contents, with enrichment in Ce and depletion in Eu, indicate that the granitoids possibly formed from partial melting of the crust. The trace elements characteristics (i.e., wide range of Hf, Ce/Ce*, Th/U and Zr/Hf values) of the zircons suggest that crystallization of the magma occurred under variable oxidation states, which spanned over a longer period, implying that our data corroborate interpretations from studies of whole-rock geochemistry and geochronology on the granitoids of northwestern Ghana. This further indicates that the evolution of the Birimian granitoids in this part of the WAC occurred earlier than what had been reported in the literature.
KW - West African Craton
KW - granitoids
KW - hydrothermal alteration
KW - magmatic evolution
KW - trace elements
KW - zircon
UR - http://www.scopus.com/inward/record.url?scp=85026907385&partnerID=8YFLogxK
U2 - 10.1007/s12583-017-0799-4
DO - 10.1007/s12583-017-0799-4
M3 - Article
AN - SCOPUS:85026907385
SN - 1674-487X
VL - 29
SP - 43
EP - 56
JO - Journal of Earth Science
JF - Journal of Earth Science
IS - 1
ER -