Granitoids and Greenstone Belts of the Pietersburg Block—Witnesses of an Archaean Accretionary Orogen Along the Northern Edge of the Kaapvaal Craton

Laurent, Oscar; Zeh, Armin; Brandl, G.; Vezinet, Adrien; Wilson, A. H.

doi:10.1007/978-3-319-78652-0_4

Cited by 21 publications

(23 citation statements)

References 91 publications

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“…The general geochemistry and ages of the granitoids of the Makoppa Dome in the Pietersburg Block were found to be similar to the data from the area to the east of the Bushveld Complex (Laurent et al, 2019). Our new zircon Hf isotope data confirm this finding for the ca.…”

Section: Pietersburg Blocksupporting

confidence: 82%

“…The two older xenocrystic cores are shown separately. In this diagram, all other Kimberley Block Hf isotopic data points are from , whereas the Pietersburg Block data are those used in the recent review paper by Laurent et al (2019). All references to the literature data are given in Electronic Supplement 2.…”

Section: Discussionmentioning

confidence: 99%

“…Further TTG intrusions followed from 3.0 to ca. 2.8 Ga, and more K-rich magmatism from 2.9 to 2.67 Ga (see Laurent et al, 2019 for a review). Magmatism has been interpreted to reflect accretion of several arcs, and a >3.2 Ga continental nucleus, to the proto-Kaapvaal Craton, consisting of the Swaziland and Witwatersrand blocks.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The two samples from the Vaalpenskraal trondhjemitic gneisses are, however, slightly different. Apart from three samples of tonalitetrondhjemite-granodiorite (TTG) of 3.35-3.25 Ga that have been interpreted to form the nucleus of a separate 'crustal nucleus' (Laurent et al, 2019), the Vaalpenskraal trondhjemite is the oldest TTG in the Pietersburg Block of which Hf isotope data have been obtained. The samples are slightly older than the ca.…”

Section: Pietersburg Blockmentioning

confidence: 99%

“…As isotopic information, unlike whole rock geochemistry, is only affected by the sources contributing to the magma, irrespective of crystal fractionation, it is a robust test for similarity among rocks of the same age. This technique has been applied successfully to a number of plutons of the Kaapvaal Craton (see overviews in Kröner et al, 2019 andLaurent et al, 2019, and the many works by coworkers (e.g. 2009, 2011)), but a great number of intrusives of which the age is known has not been analysed for the Hf isotopic composition.…”

Section: Introductionmentioning

confidence: 99%

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

Elburg

Poujol²

2020

South African Journal of Geology

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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 to 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 to 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 to 3.0 Ga followed by successive crust reworking until 2.77 Ga. Lavas of the Ventersdorp Supergroup, for which zircon grains from a ca. 2.75 lapilli tuff give εHfi of +2, are the first evidence of a juvenile source, after 300 Myr of crustal reworking.

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Section: Pietersburg Blocksupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Geological Backgroundmentioning

confidence: 99%

Section: Pietersburg Blockmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Elburg

Poujol²

2020

South African Journal of Geology

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Probing the southern African lithosphere with magnetotellurics, Part II, linking electrical conductivity, composition and tectono-magmatic evolution.

Özaydın¹,

Selway²,

Griffin³

et al. 2021

Preprint

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The tectonic history of Southern Africa includes Archean formation of cratons, multiple episodes of subduction and rifting and some of the world's most significant magmatic events. These processes left behind a compositional trail that can be observed in xenoliths and measured by geophysical methods. The abundance of kimberlites in southern Africa makes it an ideal place to test and calibrate mantle geophysical interpretations that can then be applied to less well-constrained regions. Magnetotellurics (MT) is a particularly useful tool for understanding tectonic history because electrical conductivity is sensitive to temperature, bulk composition, accessory minerals and rock fabric. We produced three-dimensional MT models of the southern African mantle taken from the SAMTEX MT dataset, mapped the properties of $\sim36000$ garnet xenocrysts from Group I kimberlites, and compared the results. We found that depleted regions of the mantle are uniformly associated with high electrical resistivities. The conductivity of fertile regions is more complex and depends on the specific tectonic and metasomatic history of the region, including the compositions of metasomatic fluids or melts and the emplacement of metasomatic minerals. The mantle beneath the $\sim 2.05$ Ga Bushveld Complex is highly conductive, probably caused by magmas flowing along a lithospheric weakness zone and precipitating interconnected, conductive accessory minerals such as graphite and sulfides. Kimberlites tend to be emplaced near the edges of the cratons where the mantle below 100 km depth is not highly resistive. Kimberlites avoid strong mantle conductors, suggesting a systematic relationship between their emplacement and mantle composition.

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The Neoarchaean Limpopo Orogeny: Exhumation and Regional-Scale Gravitational Crustal Overturn Driven by a Granulite Diapir

Reenen

Smit

Perchuk

et al. 2019

Regional Geology Reviews

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Granitoids and Greenstone Belts of the Pietersburg Block—Witnesses of an Archaean Accretionary Orogen Along the Northern Edge of the Kaapvaal Craton

Cited by 21 publications

References 91 publications

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

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

Probing the southern African lithosphere with magnetotellurics, Part II, linking electrical conductivity, composition and tectono-magmatic evolution.

The Neoarchaean Limpopo Orogeny: Exhumation and Regional-Scale Gravitational Crustal Overturn Driven by a Granulite Diapir

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