| Autor: |
Jiao Li, Yi Chen, Xiao-Xiao Ling, Guo-Qiang Tang, Yu Liu, Xian-Hua Li, Jean Pierre Tchouankoue, Chuan-Zhou Liu |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Precambrian Research. 294:307-321 |
| ISSN: |
0301-9268 |
| Popis: |
High-precision geochronological framework is crucial to understanding of the evolution of orogenesis. As part of the Pan-African North Equatorial Fold Belt, the Neoproterozoic Fold Belt of Cameroon (NFBC) involved polyphase deformation (D1 to D4 phases), metamorphism (up to granulite facies) and widespread crustal anatexis and magmatism. While a general geochronological framework has been established, controversy still exists on the temporal evolution of the metamorphic and magmatic events associated with polyphase deformation, in particular, the accurate age and geodynamic manifestations underlining the end of the orogeny are yet to be well constrained. We conduct in this work integrated analyses of SIMS U-Pb zircon and monazite dating and in-situ zircon Hf-O isotopes on the orthogneiss, leucosome and granite samples from Wum and Yaounde of southwestern Cameroon in order to provide further constraints on temporal evolution of the NFBC. Our high-precision SIMS U-Pb age data demonstrate that the magmatic protoliths of orthogneisses from Wum and Yaounde were emplaced synchronously at ca. 620 Ma. They were generated by partial melting of the thickened Paleoproterozoic crustal basement rocks with zircon Hf TDMc model age of ca. 1.9–2.0 Ga. Metamorphic zircons and two generations of monazites from an in-situ leucosome within the granulitic paragneiss of the Yaounde Group yield indistinguishable ages of ca. 610 Ma. These new results, in combination with previous isotopic data, suggest that the Yaounde Group supracrustal rocks with zircon Hf TDMc model age of ca. 1.7 Ga experienced a very rapid evolution from sedimentation at |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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