Neoarchean arc magmatism and Paleoproterozoic high-pressure granulite-facies metamorphism in the southern Motloutse Complex, eastern Botswana: Implications for the western extension of the Limpopo Complex

Petrology and geochronology of sapphirine‐bearing granulites from the Limpopo Complex in eastern Botswana: Implications for Palaeoproterozoic long‐lived high‐pressure/ultrahigh‐temperature metamorphism and rapid exhumation

“…Zeh, Gerdes, and Barton Jr. (2009) reported ~2.0 Ga Palaeoproterozoic metamorphic zircon overgrowth around magmatic grains (2,610 ± 7 Ma) from granitoids from the Phikwe Complex. From the Motloutse Complex, Zeh et al (2009) reported 2,056 ± 12 Ma zircon overgrowth ages from a tonalite gneiss, Rajesh, Mokatse, and Wan (2020) obtained 2,013 ± 18 Ma zircon overgrowth ages from <3.0 Ga peridotite, and recently, Basupi et al (2022) reported 2,020.2 ± 4.9 Ma thermal event from a garnet‐bearing amphibolite. All ages were inferred as high‐grade metamorphism and related magmatic events.…”

“…However, the absence of Mg‐rich staurolite, an indicator of P > 15 kbar deep crustal metamorphism (e.g., Nishimiya, Tsunogae, & Santosh, 2010), from the Botswanan side and its presence in the South African and Zimbabwean sides indicate that a shallow crustal level is exposed in the western part of the BBC in Botswana. The peak P–T conditions from such supracrustal lithologies decrease further west to the southern Motloutse Complex (~10 kbar; Basupi et al, 2022), indicating the decreasing metamorphic grade toward west in the CZ.…”

“…3.36–3.5 Ga Messina Layered Intrusion (Barton Jr., 1996; Mouri, Whitehouse, Brandl, & Rajesh, 2009; Zeh et al, 2010), and Neoarchean granitoid gneisses (e.g., the Allday Gneiss, Bulai Pluton, Singelele Gneiss, Verbaard Gneiss, Zanzibar Gneiss, and Zoetfontein Gneiss emplaced between 2.73 and 2.60 Ga; e.g., Hofmann, Kröner, & Brandl, 1998; Jaeckel et al, 1997; Kröner et al, 1999; Kröner, Jaeckel, Hofmann, Nemchin, & Brandl, 1998; Millonig, Zeh, Gerdes, & Klemd, 2008; Zeh, Gerdes, Klemd, & Barton Jr., 2007). In Botswana, the Semolale and Phikwe/Mahalapye Complexes are the western extension of the NMZ and CZ, respectively (Aldiss, 1991; Basupi, Tsunogae, Takahashi, & Tsutsumi, 2022; Carney, Aldiss, & Lock, 1994; Holzer, Barton, Paya, & Kramers, 1999) (Figure 1). Metasupracrustal successions and granitoid gneisses similar to the BBC's lithologies (the Baines Drift Complex) occur south of the Phikwe Complex around the Baines Drift area, near the South African border (Figures 1 and 2).…”