jabbrv-ltwa-all.ldf jabbrv-ltwa-en.ldf Lithospheric Structure Beneath the Cameroon Volcanic Line: Implications for the Melt Source

To understand the melt source of hotlines with asynchronous volcanoes, we investigate the lithospheric structure of the Cameroon Volcanic Line (CVL), a chain of volcanoes without age progression stretching from the Gulf of Guinea into Central Africa. We analyze Bouguer gravity anomalies from the World Gravity Model 2012 using 2‐D power spectrum techniques and 2-D forward modeling to estimate crustal and lithospheric thickness. We find: (1) thin crust (20–30 km) beneath the oceanic CVL; (2) thick crust (30–43 km) beneath the continental CVL and Oubanguides Belt, and thicker crust (43–50 km) beneath the Congo Craton; (3) thin lithosphere (90–120 km) beneath the oceanic CVL and thinner lithosphere (75–90 km) beneath the continental CVL; and (4) thicker lithosphere (150–234 km) beneath the Congo Craton. Our seismic-constrained forward models reveal a delaminated body beneath the continental CVL and a sharp transition from thick lithosphere beneath the Congo Craton to thin lithosphere beneath the Oubanguides Belt. We interpret lithospheric delamination as the cause of the thin lithosphere beneath the continental CVL. The delaminated body deflects rising mantle plume materials preferentially southward, producing the Y-shaped distribution of continental volcanoes. Edge-Driven Convection (EDC), focuses the plume materials beneath the thin lithosphere, producing the continental CVL. EDC and an oceanward flow of the plume materials produce the oceanic CVL with oceanward younging. We conclude that only the continental CVL lacks age progression due to a complex interaction of the rising plume with the delaminated body and the lithospheric architecture.