Datingsouthamerica org

01 Apr

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.

Cenozoic opening of the central Scotia Sea involved the tectonic translation of crustal blocks to form the North Scotia Ridge, which today is a major topographic constriction to the flow of the deep Antarctic Circumpolar Current that keeps Antarctica thermally isolated from warmer ocean waters.

How this ridge developed and whether it was a topographic barrier in the past are unknown.

Insieme a MUTEC ricoprirà nel 2018 un ruolo importante nell’ambito della tutela del patrimonio culturale europeo.

Because models of the evolution of the ACC are tied to the tectonic reconstructions that restore microcontinental blocks and volcanic arcs to pre–seafloor spreading locations, it is essential that pre-drift locations are well defined.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).The motivation for this model was driven by the need to explain an apparent deficit in the translation of South Georgia accounted for by seafloor spreading based on a South American origin.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.