TY - JOUR
T1 - Archean to Paleoproterozoic crustal evolution in the Sassandra-Cavally domain (Côte d'Ivoire, West Africa)
T2 - Insights from Hf and U-Pb zircon analyses
AU - Koffi, Augustin Y.
AU - Thébaud, Nicolas
AU - Kouamelan, Alain N.
AU - Baratoux, Lenka
AU - Bruguier, Olivier
AU - Vanderhaeghe, Olivier
AU - Pitra, Pavel
AU - Kemp, Anthony I.S.
AU - Evans, Noreen J.
N1 - Funding Information:
This project is part of a PhD study of A.Y.K. funded by the T2GEM project (Geophysical and Geochemical Technologies for Mineral Exploration). We wish to gratefully acknowledge AMIRA International and the industry sponsors, for their support of the WAXI project (P934B). We are also appreciative of the contribution of the various geological surveys department of mines in West Africa as sponsors in kind of WAXI. The authors acknowledge the French National Research Institute for Sustainable Development (IRD, LMI MINERWA Laboratory for Responsible Mining in West Africa) for funding a part of this research project. The authors wish to thank Brad McDonald (Curtin University) for technical assistance during analysis. GeoHistory Facility instruments were funded via an Australian Geophysical Observing System grant provided to AuScope Pty Ltd. by the AQ44 Australian Education Investment Fund program. The NPII multi-collector and laser ablation system at UWA were obtained via funding from the Australian Research Council LIEF program (LE150100013). NT would like to acknowledge the Hammond and Nisbet trust for its support. The authors gratefully acknowledge two anonymous reviewers and Bernard Bingen for their constructive reviews. We also thank Chris Fisher and Oscar Laurent for their insights into the isotopic geochemistry which greatly helped improve the quality of this manuscript.
Funding Information:
This project is part of a PhD study of A.Y.K. funded by the T2GEM project (Geophysical and Geochemical Technologies for Mineral Exploration) . We wish to gratefully acknowledge AMIRA International and the industry sponsors, for their support of the WAXI project (P934B). We are also appreciative of the contribution of the various geological surveys department of mines in West Africa as sponsors in kind of WAXI. The authors acknowledge the French National Research Institute for Sustainable Development (IRD, LMI MINERWA Laboratory for Responsible Mining in West Africa) for funding a part of this research project. The authors wish to thank Brad McDonald (Curtin University) for technical assistance during analysis. GeoHistory Facility instruments were funded via an Australian Geophysical Observing System grant provided to AuScope Pty Ltd. by the AQ44 Australian Education Investment Fund program. The NPII multi-collector and laser ablation system at UWA were obtained via funding from the Australian Research Council LIEF program (LE150100013). NT would like to acknowledge the Hammond and Nisbet trust for its support. The authors gratefully acknowledge two anonymous reviewers and Bernard Bingen for their constructive reviews. We also thank Chris Fisher and Oscar Laurent for their insights into the isotopic geochemistry which greatly helped improve the quality of this manuscript.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/11
Y1 - 2022/11
N2 - Crustal evolution in the south West African Craton is dominated by a significant input of juvenile material into the crust at ca. 2.1 Ga and it remains unclear how much of the Paleoproterozoic continental mass was influenced by the presence of pre-existing Archean crustal domains. The Sassandra-Cavally (SASCA, Côte d'Ivoire) domain is strategically located east of the Sassandra shear zone at the transition of the Paleoproterozoic and Archean terranes of the Leo-Man shield. Combined U-Pb and Lu-Hf isotopic analyses by LA-(MC-)ICP-MS were acquired on zircon grains extracted from migmatitic gneisses, metasedimentary rocks and a granitic intrusion. The migmatitic gneisses, yield Archean ages between ca. 3330 and 2810 Ma with εHf ranging from −9.4 to + 3.3 and a metamorphic age at 2076 ± 6 Ma. They are tentatively interpreted as orthogneisses extracted from the mantle during the Paleoarchean and reworked substantially in the Mesoarchean. Detrital zircon grains from metasedimentary units adjacent to the Archean migmatitic gneisses yield ages ranging from ca. 2213 to 2088 Ma with εHf ranging from + 0.0 to + 5.5, indicating derivation from juvenile Paleoproterozoic source rocks. A granite intrusion was dated within uncertainty of the metamorphic age at 2084 ± 6 Ma. It exhibits a hybrid isotopic signature with εHf forming two distinct clusters between −4.9 and −8.5, and between + 2.2 and + 6.5 for inherited zircon grains dated between ca. 2343 to 2100 Ma. The near continuous U-Pb age record from this early Mesoarchean event to the Neoarchean is associated with constant initial 176Hf/177Hf suggesting for an ancient lead loss event at ca. 2800 Ma or a prolonged period of zircon dissolution/precipitation and/or crystallization. This early period is followed by peaks of zircon dates highlighting crustal extraction during the Eoeburnean (ca. 2250 to 2150 Ma) and Eburnean orogenies (ca. 2140 to 2100 Ma). The absence of detrital zircon of the ages similar to those of migmatitic gneisses (∼3200–2800 Ma) in Paleoproterozoic metasediments suggests their deposition distal from the Archean terranes followed by a tectonic assemblage of the SASCA domain during the later stages of the Eburnean orogeny.
AB - Crustal evolution in the south West African Craton is dominated by a significant input of juvenile material into the crust at ca. 2.1 Ga and it remains unclear how much of the Paleoproterozoic continental mass was influenced by the presence of pre-existing Archean crustal domains. The Sassandra-Cavally (SASCA, Côte d'Ivoire) domain is strategically located east of the Sassandra shear zone at the transition of the Paleoproterozoic and Archean terranes of the Leo-Man shield. Combined U-Pb and Lu-Hf isotopic analyses by LA-(MC-)ICP-MS were acquired on zircon grains extracted from migmatitic gneisses, metasedimentary rocks and a granitic intrusion. The migmatitic gneisses, yield Archean ages between ca. 3330 and 2810 Ma with εHf ranging from −9.4 to + 3.3 and a metamorphic age at 2076 ± 6 Ma. They are tentatively interpreted as orthogneisses extracted from the mantle during the Paleoarchean and reworked substantially in the Mesoarchean. Detrital zircon grains from metasedimentary units adjacent to the Archean migmatitic gneisses yield ages ranging from ca. 2213 to 2088 Ma with εHf ranging from + 0.0 to + 5.5, indicating derivation from juvenile Paleoproterozoic source rocks. A granite intrusion was dated within uncertainty of the metamorphic age at 2084 ± 6 Ma. It exhibits a hybrid isotopic signature with εHf forming two distinct clusters between −4.9 and −8.5, and between + 2.2 and + 6.5 for inherited zircon grains dated between ca. 2343 to 2100 Ma. The near continuous U-Pb age record from this early Mesoarchean event to the Neoarchean is associated with constant initial 176Hf/177Hf suggesting for an ancient lead loss event at ca. 2800 Ma or a prolonged period of zircon dissolution/precipitation and/or crystallization. This early period is followed by peaks of zircon dates highlighting crustal extraction during the Eoeburnean (ca. 2250 to 2150 Ma) and Eburnean orogenies (ca. 2140 to 2100 Ma). The absence of detrital zircon of the ages similar to those of migmatitic gneisses (∼3200–2800 Ma) in Paleoproterozoic metasediments suggests their deposition distal from the Archean terranes followed by a tectonic assemblage of the SASCA domain during the later stages of the Eburnean orogeny.
KW - Archean
KW - Crustal growth and reworking
KW - Côte d'Ivoire
KW - Juvenile crustal growth
KW - U-Pb and Lu-Hf isotopes
KW - West African Craton
KW - Zircon geochronology
UR - http://www.scopus.com/inward/record.url?scp=85140085020&partnerID=8YFLogxK
U2 - 10.1016/j.precamres.2022.106875
DO - 10.1016/j.precamres.2022.106875
M3 - Review article
AN - SCOPUS:85140085020
SN - 0301-9268
VL - 382
JO - Precambrian Research
JF - Precambrian Research
M1 - 106875
ER -