Other
Scientific paper
Nov 1977
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1977e%26psl..37..117c&link_type=abstract
Earth and Planetary Science Letters, Volume 37, Issue 1, p. 117-123.
Other
1
Scientific paper
The metabasic Marydale Formation of the Kheis Group occupies a zone of contact between the Sanama and Kaapvaal structural provinces of South Africa. Stratigraphic relationships between the two provinces are not well understood. Whilst the well-known Kaapvaal basement and supracrustal succession yield radiometric ages older than 1900 m.y., Sanama Province ages reflect a Kibaran (1200 +/- 200 m.y.) tectogenetic cycle. The age of the Marydale, stratigraphically the oldest Sanama formation, has been variously estimated at >2500 m.y., about 2000 m.y., or Kibaran, based on controversial field interpretations or on available radiometric data. Rb-Sr data are presented for Marydale samples from a nappe-like body which, having been thrust over the Kaapvaal basement, was shielded from metamorphism. Two types of alteration are described and possible causes of isotopic homogenisation are discussed. It is concluded that an isochron age of 1899 +/- 57 m.y. (I = 0.7040 +/- 0.0003) represents the age of extrusion of the Marydale volcanics. The stratigraphic controversy is thus resolved, Kheis Group formations being approximately coeval with the Matsap, the youngest formation of the Kaapvaal Precambrian succession. The implications of this and other recent work to theories of crustal evolution are considered. It is suggested that the continental crust of Sanama Province originated partly during the Eburnian (2000 +/- 100 m.y.) period of African orogeny and partly during the Kibaran tectogenetic cycle during which the province became cratonised and was added to the Southern African cratonic block.
No associations
LandOfFree
A post-Transvaal age for the Marydale Formation, Kheis Group, Southern Africa does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A post-Transvaal age for the Marydale Formation, Kheis Group, Southern Africa, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A post-Transvaal age for the Marydale Formation, Kheis Group, Southern Africa will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1131137