Geochemistry of Ahoko claystone-shale sequence, south eastern Bida Basin, Nigeria: implications for tectonic setting, provenance and source area weathering
| Autor: | Wilson M. Gitari, A. O Ojo, Olusola A. OlaOlorun, Segun A. Akinyemi, Henry Y. Madukwe, Olajide Femi Adebayo, Adeyinka O. Aturamu, Abuh Momoh |
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| Rok vydání: | 2018 |
| Předmět: |
Provenance
010504 meteorology & atmospheric sciences Archean Continental crust Geochemistry Weathering General Medicine engineering.material 010502 geochemistry & geophysics 01 natural sciences Sedimentary depositional environment Tectonics engineering General Earth and Planetary Sciences Plagioclase General Agricultural and Biological Sciences Oil shale Geology 0105 earth and related environmental sciences General Environmental Science |
| Zdroj: | Transactions of the Royal Society of South Africa. 73:158-171 |
| ISSN: | 2154-0098 0035-919X |
| Popis: | Results of geochemical investigation of shale and claystone samples from two different sections of the exposed Ahoko claystone-shale sequence along the Koton-Karifi/Abaji highway are presented and discussed. Chemical variation of SiO2/Al2O3 and Na2O/K2O is ascribed to varying degrees of weathering of plagioclase rich rock either at the source and/or during transportation to the depositional basin. The high Chemical Index of Alteration (CIA) and Chemical Index of Weathering (CIW) values indicate intense alteration/weathering and removal of mobile cations. The CIW/CIA ratios indicate material that has undergone short distance transportation before final deposition. Besides, the overall Index of Compositional Variability (ICV) values and lower contents of Rb and Cs than upper continental crust (UCC) and post Archean Australian shale (PAAS) of both profiles (i.e. AH-1 and AH-2) indicate intense weathering. The average Th/U ratio is less than the average values for UCC and PAAS, which indicates that the source... |
| Databáze: | OpenAIRE |
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