Möwe Bay Dykes, Northwestern Namibia: Geochemical and geochronological evidence for different mantle source regions during the Cretaceous opening of the South Atlantic

Conjugate volcanic passive margins in the austral segment of the South Atlantic – Architecture and development

“…By contrast, the younger generation of dyke shows a more 'primitive' composition deriving from a depleted asthenosphere source. These results suggest the progressive thinning of the lithosphere between 135 and 113 Ma (Will et al, 2016;McMaster et al, 2019).…”

“…The austral South Atlantic opening is contemporaneous with Early Cretaceous voluminous magmatism found onshore, in conjugate dykes swarms (Fig. 1; Almeida et al, 2013;Will et al, 2016;McMaster et al, 2019), a set of intrusive centers identified onshore Namibia (Corner et al, 2000(Corner et al, , 2002 and in the Paraná and Etendeka continental flood basalts (Peate et al, 1992;Turner et al, 1994). Offshore, this magmatism was drilled at the top of the high-frequency seismic reflectors packages forming the so-called sequences of SDR (Hinz, 1981;Wickens and McLachlan, 1990;Gladczenko et al, 1997Gladczenko et al, , 1998Hinz et al, 1999;Franke et al, 2007;Koopmann et al, 2014a;Soto et al, 2011;Stica et al, 2014;Gordon et al, 2017;Fig.…”

“…2) span from 135 to 113 Ma (e.g., Almeida et al, 2013. The recent works of Will et al (2016) and McMaster et al (2019) document the petrogenetic evolution between three main generations of tholeiitic dykes. The two older generations exhibit very similar compositions with the Parana-Etendeka basalts and would be contaminated by an enriched component (lithospheric mantle or continental crust).…”

Hotspot tracks in the South Atlantic located above bands of fast flowing asthenosphere driven by waning pulsations from the African LLSVP

“…(Möwe Bay area) (Will et al, 2016). The late ~113 Ma generation dykes is chemically and isotopically identical to coeval rocks from the northeastern end of Walvis Ridge (Will et al, 2016). Schematic reconstructions (Fig.…”

Publisher’s Note

“…Apart from the age of the basalts, there is controversy about the source of Paraná-Etendeka magmas (see e.g. Renne et al, 1992;Peate, 1997;Hawkesworth et al, 1999;Trumbull et al, 2007;Rocha-Júnior et al, 2013;Comin-Chiaramonti et al, 2011;Will et al, 2016;Foulger, 2017).…”