U\u2013Pb ages of detrital zircons in Cretaceous\u2013Paleogene/Neogene kaolins within Eastern Dahomey and Niger Delta Basins (Nigeria) as provenance indicators

Olaonipekun Oyebanjo,John Odiyo,Georges-Ivo Ekosse

doi:10.1038/s41598-021-93453-9

Olaonipekun Oyebanjo, John Odiyo + Show 1 more

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https://doi.org/10.1038/s41598-021-93453-9

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Abstract

Detrital zircon grains within four (4) deposits including two (2) Cretaceous and two (2) Paleogene/Neogene kaolins in Nigeria were analysed using U–Pb LA-SFICP-MS to determine their provenance. The zircon textures were dominated by xenocrystic cores and oscillatory zoning in the Cretaceous and Paleogene/Neogene kaolins, respectively. The Th/U ratios obtained for the detrital zircon grains within the kaolins were predominantly within known values for rocks with magmatic origin. The age populations obtained for the detrital zircon grains were dominated by values from 529 to 978 Ma within the Neoproterozoic, followed by values from 1754 to 2497 Ma of the Paleoproterozoic. Detrital zircon ages obtained between 553.2 ± 6.2 and 583.5 ± 2.0 Ma represent part of the minimum provenance ages for the primary minerals that were kaolinised. The Cretaceous–Paleogene/Neogene kaolins were derived from parent rocks of Eburnean and Pan African ages within the Western and Northern Nigeria Basements.

Highlights

Age constraints for kaolins have relied greatly on relative dating by identifying localities of deposits where they are correlated to profiles developed on or overlain by sediment or rock of known ages[1,2]
The studied Cretaceous Eruku and Lakiri kaolin deposits occur within the Abeokuta Group (Ise, Afowo, and Araromi Formations) of the Eastern Dahomey Basin, whereas the Paleogene/Neogene Awo-Omama and Ubulu-Uku kaolin deposits occur within the Ogwashi-Asaba Formation of the Niger Delta Basin (Fig. 2)
The studied detrital zircon grains were generally characterised by subhedral crystals within the Cretaceous kaolins which suggested relatively distant sediment sources

Summary

Introduction

Age constraints for kaolins have relied greatly on relative dating by identifying localities of deposits where they are correlated to profiles developed on or overlain by sediment or rock of known ages[1,2]. Despite the large occurrences of kaolin deposits and studies on kaolins in Nigeria, no investigation on the provenance of the Cretaceous and Paleogene/Neogene kaolins using detrital zircon geochronology has been reported. This study investigated the U–Pb detrital zircon geochronology of kaolins from the Eastern Dahomey and Niger Delta Basins in Nigeria. The studied Cretaceous Eruku and Lakiri kaolin deposits occur within the Abeokuta Group (Ise, Afowo, and Araromi Formations) of the Eastern Dahomey Basin, whereas the Paleogene/Neogene Awo-Omama and Ubulu-Uku kaolin deposits occur within the Ogwashi-Asaba Formation of the Niger Delta Basin (Fig. 2). The mineralogical analyses of the kaolins showed that the Lakiri deposit is composed of pure kaolins, whereas the Eruku, Awo-Omama, and Ubulu-Uku deposits were composed of sandy kaolins This is due to the relatively higher percentages of quartz in the latter d eposits[19]. The kaolins were mainly composed of kaolinite and quartz with trace amounts of muscovite, anatase, hematite, and goethite

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