Skip to Main content Skip to Navigation
Journal articles

Lu-Hf analyses of zircon from the Makoppa Dome and Amalia-Kraaipan area: 1 implications for evolution of the Kimberley and Pietersburg blocks of the Kaapvaal Craton.

Abstract : Previously dated zircon crystals from the Amalia-Kraaipan granite-greenstone belts and Makoppa Dome were analysed for their Lu-Hf isotopic characteristics to refine the geological evolution of these areas. Samples from the Makoppa Dome, belonging to the Pietersburg Block, largely fall within the epsilon Hf-age range for granitoids from the eastern part of the block. However, the oldest 3.01-3.03 Ga trondhjemitic gneisses show that reworking of juvenile mafic crust started earlier in the western than the eastern part of the block, suggesting a diachronous tectonic evolution. The three granitoids from the Amalia-Kraaipan area fall within the field for Pietersburg and Kimberley block granitoids. Contribution from older crustal material is seen in a 3.08 Ga schist, likely derived from a volcanic protolith, from the Madibe Belt, in the far east of the Kimberley Block, with a mantle extraction age of 3.25-3.45 Ga. The data suggest that the Kimberley Block, like the Pietersburg Block, also contains (minor) ancient crustal components, derived from a depleted mantle source prior to 3.1 Ga. The new data suggest that the Kimberley and Pietersburg blocks underwent a very similar Paleo- to Mesoarchean crustal evolution, with a major crust formation event at 3.1-3.0 Ga followed by successive crust reworking until 2.77 Ga. Lavas of the Ventersdorp Supergroup, for which zircons from a ca. 2.75 lapilli tuff give Hfi of +2, are the first evidence of a juvenile source, after 300 Myr of crustal reworking.
Document type :
Journal articles
Complete list of metadatas

Cited literature [49 references]  Display  Hide  Download

https://hal-insu.archives-ouvertes.fr/insu-02885429
Contributor : Isabelle Dubigeon <>
Submitted on : Tuesday, June 30, 2020 - 4:39:24 PM
Last modification on : Thursday, July 9, 2020 - 3:14:10 AM

File

 Restricted access
To satisfy the distribution rights of the publisher, the document is embargoed until : 2020-12-30

Please log in to resquest access to the document

Identifiers

Collections

Citation

Marlina Elburg, Marc Poujol. Lu-Hf analyses of zircon from the Makoppa Dome and Amalia-Kraaipan area: 1 implications for evolution of the Kimberley and Pietersburg blocks of the Kaapvaal Craton.. South African Journal of Geology, Geological Society of South Africa, In press, ⟨10.25131/sajg.123.0025⟩. ⟨insu-02885429⟩

Share

Metrics

Record views

47