The three-dimensional lithospheric structure of the Falkland Plateau region based on gravity modelling

Abstract

Abstract:The lithospheric structure of the Falkland Plateau region has been modelled by making an initial estimate on the basis of local isostasy and then refining the geometries by inversion of gravity anomalies. The model predicts a crustal thickness beneath the Falkland Plateau Basin that is more than twice that previously inferred from seismic evidence. The preferred explanation is that the seismic survey detected high-velocity (?underplated) lower crust rather than upper mantle. This is compatible with the results of deep seismic experiments over the conjugate Filchner Block of Antarctica and also appears likely on the basis of the position of the Falkland Plateau Basin in relation to the Karoo-Ferrar magmatic province at the time of extension. Continental crust is inferred to be continuous beneath the northern part of the Falkland Plateau, as there are consistent magnetic and flexural anomalies associated with the continent-ocean boundary. Flexural modelling of the southern margin of the plateau indicates lateral variations in strength, with the strongest lithosphere beneath the Falkland Plateau Basin. This may indicate thick oceanic crust beneath the southern part of the basin or the effect of thinning relatively weak continental crust and replacing it with relatively strong underplating. [End of Abstract]

The Falkland Basins - New Structural Model and Hydrocarbon Bearing Prospects (by Remote Sensing and Geoelectric Data)

“…It is a tectonic belt with complex crustal structure separating the Mesozoic/Cenozoic magmatic arcs of these continents [2,9,10,13].…”

“…Most of new oceanic crust in the Western part of Scotia plate has been formed in Cenozoic by sea-floor spreading processes, which are marked by the oldest linear magnetic anomalies of the Scotia Sea [2,9,13].…”

“…First geophysical data, including DSS-data for this area were published in 1964 [14,15]. Complex deep geophysical models were published only some years ago [2,9]. New geophysical data have revealed the internal structure of sedimentary basin ( Fig.…”

“…New geophysical data have revealed the internal structure of sedimentary basin ( Fig. 3) and indicate the presence of a sedimentary section ranging from 2 to 10 km in thickness [9].…”

“…Formation and evolution of a broad tectonic zone with the Falkland Basin, Drake Passage and the Scotia Sea (Scotia Plate) bottom structures was a subject of geological and geophysical investigations for a long time because this structural unit is one of the most interesting features in this part of the Southern Atlantic Ocean [1,2,9,10,13,17].…”