The Drake Passage asthenospheric and oceanic gateway

Through Earth's history, the evolution of both mantle and oceanic gateways entails a series of processes that culminate in global changes. This synthesis article focuses on the linkages among mantle, crustal, oceanographic and global change processes that are involved in the evolution of a gateway. These processes include the upper mantle dynamics, the thermal structure of the lithosphere, tectonic processes, oceanic current distribution, and evolution of biota. Such processes are recorded at different layers of the lithosphere, for instance, as magnetic properties of the crust or ocean sediments. Feedback between mantle dynamics and lithospheric stresses are involved in rifting, oceanic spreading, subduction and collisional processes. The thermal state of the lithosphere controls elevation of the seafloor, for example. To understand the linkages, we summarize the processes involved in what is proposed to be the final break-up of the Gondwana supercontinent, the breakup between South America and Antarctica and the formation of the Drake Passage. This break-up allowed for the flow of upper mantle material as well as for the initiation of the Antarctic Circumpolar Current which translated later into thermal isolation of Antarctica and diversification/extinction of species. The different tectonic processes identified in the Drake Passage and Scotia Sea since its formation modified the free flow of asthenospheric material as well as oceanic currents with significant implications for the formation of new oceanic crust and for the evolution of the thermal state of the lithosphere. In a similar way, the same tectonic processes had an impact on ocean circulation which affected biota and climate in the Antarctic region and globally. The ability to identify how all these processes are interlinked implies a considerable gain of knowledge for our understanding on how our planet operates and how interior dynamics affect life on the surface.