Today the Subantarctic Front and the Polar Front follow gaps in the North Scotia Ridge while the Southern Antarctic Circumpolar Current Front takes an eastward path before heading north, turning around the eastern end of South Georgia; however, how much of a barrier these ridges were in the past is unknown due in part to uncertainty about their pre-breakup location and subsequent drift history.The conventional view (Dalziel et al., 1975, 2013a; Livermore et al., 2007), based on interpretations that match the geology of the South Georgia microcontinent with South America, is that originally South Georgia occupied a position to the immediate southeast of Tierra del Fuego from the Jurassic until the Cenozoic, when seafloor spreading created the west Scotia Sea.
Apatite thermochronometry results show that South Georgia had remained connected to South America until ca.
45–40 Ma; both record a distinct rapid cooling event at that time.
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Details verbergen PCI DSS ist ein facettenreicher Sicherheitsstandard, der Anforderungen hinsichtlich Sicherheitsmanagement, Richtlinien, Verfahren, Netzwerkarchitektur, Softwaredesign und anderen wichtigen Sicherheitsmaßnahmen abdeckt.Furthermore, because the three main fronts to the modern ACC are steered by regional bathymetry (Fig.1), models of the ancient ACC need to incorporate constraints as to where and when crustal blocks were barriers to ocean currents.To address this we investigated the Cenozoic history of the South Georgia microcontinental block, the exposed part of the ridge.Detrital zircon U-Pb geochronology data confirm that the Cretaceous succession of turbidites exposed on South Georgia was stratigraphically connected to the Rocas Verdes backarc basin, part of the South America plate.However, plate kinematic data have, controversially, been used to suggest that the pre–seafloor spreading location was at the eastern end of the North Scotia Ridge and that South Georgia once belonged to part of an extended continental margin along the Falkland Plateau that formed as Gondwana broke up in Jurassic time (Eagles, 2010a).