Lithostratigraphic correlations in the western branch of the Pan-African Saldania belt, South Africa: The Malmesbury Group revisited

dc.contributor.authorBelcher R.W.
dc.contributor.authorKisters A.F.M.
dc.date.accessioned2011-05-15T16:00:34Z
dc.date.available2011-05-15T16:00:34Z
dc.date.issued2003
dc.description.abstractA new lithostratigraphic subdivision is proposed for the low-grade metamorphic, supracrustal rocks of the Pan-African Saldania Belt of the Western Cape Province South Africa, previously referred to as the Malmesbury Group. Two tectonostratigraphic groups can be distinguished that appear to be separated by an unconformity. The lower of these groups is termed the Swartland Group. There are no absolute age constraints for the Swartland Group, but a penetrative D1 deformation in rocks of the Swartland Group is correlated with the onset of oblique crustal convergence along the Pan-African West Coast Belts at ca. 580 to 570 Ma, which also provides an upper age limit of the Swartland Group. The structural evolution and style of deformation suggest a correlation of the Swartland Group with part of both the Gilberg Group of the Vanrhynsdorp Basin and the Port Nolloth Group of the Gariep Belt to the north of the Salclania Belt. The Swartland Group is unconformably overlain by mainly clastic sediments that lack evidence of the early D1 deformation and that are here referred to as the Malmesbury Group. A lower age bracket of the Malmesbury Group is provided by the presumed age of deformation of the underlying Swartland Group (ca. 575 Ma), while a minimum age of ca. 550 Ma is indicated by the intrusion of the oldest phases of the Cape Granite Suite that cross-cut the lithologies and fabrics of the Malmesbury Group. The lithological evolution and age of the Malmesbury Group suggests it correlation with the late orogenic clastic deposits of the Late-Neoproterozoic to Early-Cambrian Nama Group that formed in the eastern foreland basins of the emerging Pan-African orogenic belts. The new subdivision no longer assumes the presence of three allochthounous terranes in the Saldania Belt and allows for a better correlation of formations with those in Pan-African belts to the north. © 2003 Geological Society of South Africa.
dc.description.versionArticle
dc.identifier.citationSouth African Journal of Geology
dc.identifier.citation106
dc.identifier.citation4
dc.identifier.issn10120750
dc.identifier.urihttp://hdl.handle.net/10019.1/11769
dc.subjectCambrian
dc.subjectlithostratigraphy
dc.subjectmetamorphic rock
dc.subjectPan African orogeny
dc.subjectstratigraphic correlation
dc.subjecttectonostratigraphy
dc.subjectunconformity
dc.subjectAfrica
dc.subjectSouth Africa
dc.subjectSouthern Africa
dc.subjectSub-Saharan Africa
dc.subjectWestern Cape
dc.titleLithostratigraphic correlations in the western branch of the Pan-African Saldania belt, South Africa: The Malmesbury Group revisited
dc.typeArticle
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