OR/14/040 Cape Meredith Complex and Gondwana break-up
| Stone, P. 2014. Recent contributions on Falkland Islands bedrock geology, with an inventory of representative lithostratigraphical specimens held by the British Geological Survey. British Geological Survey Internal Report, OR/14/040. |
No new field or laboratory work has been reported from the Proterozoic, Cape Meredith Complex ‘basement’, but published data has been used by Ramos (2008)[1] to reiterate the correlation with the Deseado Massif of Patagonia that was illustrated by Borrello (1963)[2]. Implicit in this correlation is rejection of the rotational model of a Falklands microplate detaching from the south-east side of South Africa as envisaged by Adie (1952)[3]. Instead, the Falkland Islands and the Falkland Plateau are seen as an original promontory from the South American continental margin, albeit one that has undergone much extension. This interpretation is also favoured by some researchers working with offshore geophysical data, for example Lawrence and others (1999)[4]. Conversely, Macdonald and others (2003)[5] stress the convincing evidence for rotation of a Falklands microplate and accommodate that within a Gondwana break-up model that treats South America as a mosaic of four separate plates. A recent review by Dalziel and others (2013)[6] also incorporate a ‘Lafonian’ microplate, rotating from an original position to the south-east of South Africa, in their reconstruction of the opening of the South Atlantic and genesis of the Scotia Arc. Note that Dalziel and others prefer the term ‘Lafonian microplate’ to ‘Falklands microplate’ — most probably as an apolitical name avoiding the Falklands-Malvinas controversy.
References
- ↑ RAMOS, V A. 2008. Patagonia: A Palaeozoic continent adrift? Journal of South American Earth Sciences, Vol. 26, 235–251.
- ↑ BORRELLO, A V. 1963. Sobre la geologia de las Islas Malvinas. Ministerio de Educación y Justica, Buenos Aires, Argentina.
- ↑ ADIE, R J. 1952. The position of the Falkland Islands in a reconstruction of Gondwanaland. Geological Magazine, Vol. 89, 401–410.
- ↑ LAWRENCE, S R, JOHNSON, M, TUBB, S R, and MARSHALLSEA, S J. 1999. Tectono-stratigraphic evolution of the North Falkland region. In: Cameron, N R, Bate, R H, and Clure, V S. (eds) The Oil and Gas Habitats of the South Atlantic. Geological Society, London, Special Publications, No. 153, 409–424.
- ↑ MACDONALD, D, GOMEZ-PEREZ, I, FRANZESE, J, SPALLETTI, L, LAWVER, L, GAHAGAN, L, DALZIEL, I, THOMAS, C, TREWIN, N, HOLE, M, and PATON, D. 2003. Mesozoic break-up of SW Gondwana: implications for regional hydrocarbon potential of the southern South Atlantic. Marine and Petroleum Geology, Vol. 20, 287–308.
- ↑ DALZIEL, I W D, LAWVER, L A, NORTON, I O, and GAHAGAN, L M. 2013. The Scotia Arc: Genesis, Evolution, Global Significance. Annual Review of Earth and Planetary Science, Vol. 41, 767–793.