Coexisting A1 and A2 granites of Kudaru Complex: implications for genetic and tectonic diversity of A-type granite in the Younger Granite province, north-central Nigeria

Petrogenesis and tectonic implication of the alkaline ferroan granites from Ropp complex, north‐central Nigeria: Clues from zircon chemistry, U–Pb dating, and Lu–Hf isotope

“…The EM2 represent fractionated OIB melt associated with crustal contamination (Zhao et al, 2010). We dismiss the possibility of magma derivation from EM1 since the generation of the Ropp complex and by extension the entire Nigerian anorogenic alkaline province is unrelated to any form of subduction (orogenic) and plume‐related events (Ahmed et al, 2021; Amuda et al, 2020; Buchannan et al, 1971; Girei et al, 2019, 2020; Kamaunji et al, 2020; Vincent et al, 2021). This leaves open the possibility that the Ropp ferroan granites originated from the EM2 source with significant crustal contamination, which is manifested greatly in the biotite granites.…”

“…LA–ICP–MS U–Pb zircon dating yield coeval intrusive ages between 161 ± 2 and 162 ± 5 for the three rock units (see Figure 7a–c) and conform to the systematic decreasing age trend from north to south (ca. 214–141 Ma) within the Nigerian anorogenic alkaline ring complexes (Figure 1b; Rahaman et al, 1984; Dickina et al, 1991; Girei et al, 2019; Kamaunji et al, 2020; Ahmed et al, 2021). However, the recently reported U–Pb zircon age of biotite granite in the study area (ca.…”

“…These features are requisite attributes that can provide crucial information on the petrogenesis and tectonic implications of anorogenic alkaline magmatism, a hotly debated topic in the geologic literature. Indeed, recent studies have shown that the Nigerian ferroan granites were generated as a result of fractional crystallization of highly differentiated basaltic (OIB) magmas from the enriched lithospheric mantle with variable contributions from the lower crust (Ahmed et al, 2021; Amuda et al, 2020; Girei et al, 2019; Kamaunji et al, 2020). However, other workers (Girei et al, 2020; Vincent et al, 2021) opined that the Nigerian A‐type granites, particularly the highly oxidized and less radiogenic Mo– and Pb–Zn mineralized biotite granites from Mada and Ningi‐Burra complexes, were derived from the lower crust with upper mantle involvement.…”

“…(c) Geological map of the Ropp alkaline ring complex (extracted from Kinnaird et al, 1985). (1) Rahaman et al (1984), (2) Van Breemen et al (1975), (3) Van Breemen and Bowden (1973), (4) Dickina et al (1991), (5) Girei et al (2019), (6) Kamaunji et al (unpublished data), (7) Kamaunji et al (2020) (8) Ahmed et al (2021), (9) Van Breemen and Bowden (1973), (10) Vincent et al (2021), (11) Amuda et al (2020), (12) Girei et al (2020). Ages of Air and Damagaran in Niger Republic are based on Rb–Sr dating obtained from Bowden et al (1976).…”

“…In addition, controversies still remain regarding the geodynamic evolution of the Nigerian alkaline province. Whether the N–S age migration is driven by reactivated shear zones along ENE–WSW trends (Ahmed et al, 2021; Black et al, 1985; Girei et al, 2019, 2020; Vincent et al, 2022), or is associated with a mantle plume hotspot (Bowden et al, 1976; Kamaunji et al, 2020) require further investigation. In addition, high precision U–Pb zircon dates are needed to further confirm the general trend of decreasing ages from north to south (Amuda et al, 2020).…”