Cryogenian crustal evolution in western Nigeria shield: whole-rock geochemistry, Sr-Nd and zircon U-Pb-Hf isotopic evidence from Bakoshi-Gadanya granites. Issue 18 (11th October 2022)

• Record Type: Journal Article
• Authors: Elatikpo, Safiyanu Muhammad; Li, Huan; Zheng, Han; Girei, Musa Bala; Wu, Jinghua; Amuda, Abdulgafar Kayode
• Is Part Of: International geology review. Volume 64:Issue 18(2022)
• Page Start: 2626
• Page End: 2652
• Publication Date: 2022-10-11
• Subjects: Bakoshi-Gadanya area -- juvenile magma source -- Neoproterozoic granites -- Pan-African orogeny -- high-K granite -- zircon U-Pb-Hf isotopes; Geology -- Periodicals; Electronic journals; 551.05
• DOI: 10.1080/00206814.2021.1998799
• Languages: English
• ISSNs: 0020-6814

Abstract

ABSTRACT: The Bakoshi-Gadanya area, with widespread Neoproterozoic granites, is located within the Pan-African Trans-Sahara Belt, sandwiched between the West African and the Sahara metacraton. The whole-rock geochemistry, Sr-Nd isotope systematics and LA-(MC)-ICP-MS U-Pb-Hf isotopes of zircon were analysed to shed light on the age and genesis of the Bakoshi-Gadanya granites in the Precambrian basement of the northern western Nigeria shield. The granites are silicic (SiO2 : 72.8–77.2 wt.%), ferroan, high-K, calc-alkalic to alkali-calcic in composition, with A-type granite affinities. The ferroan calc-alkalic types range in age from 706.6 ± 1 Ma to 638.4 ± 1 Ma, and the alkali-calcic type is dated at 710 ± 1 Ma. Whole-rock Sr-Nd and zircon Hf isotope systematics have constrained the ferroan calc-alkalic granites to an enriched mantle lithospheric magma source, contaminated by Archaean-Palaeoproterozoic crustal components. On the other hand, the magma that crystallized the alkali-calcic Gadanya granite originated from an enriched mantle source, triggered by reactivation of the lithosphere-scale Kalangai fault during the post 750 Ma major collision between West African Craton and the Saharan metacraton. Both alkali-calcic and calc-alkalic ferroan granites were formed contemporaneously with the last major Pan-African syn-metamorphic deformation in northern western Nigerian shield; thus, they are syn-kinematic granites. Neoproterozoic magmatism at Bakoshi-Gadanya area is related to easterly dipping subduction at the margin of microcontinental blocks in northern western Nigeria shield. Zircon U-Pb-Hf data envisaged both early Neoproterozoic and Cryogenian juvenile magmatic additions in this part of western Nigeria shield. Graphical abstract: uf0001