Petrology and geochronology of low-pressure mafic granulites in the Marydale Group, South Africa

Humphreys, H. C.; Cornell, David H.

doi:10.1016/0024-4937(89)90031-5

Cited by 13 publications

(6 citation statements)

References 27 publications

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“…The significance of this date is not certain as the Rb-Sr isotope system in dykes is notorious for providing inaccurate or spurious intrusion ages. Humphreys and Cornell (1989) described high-grade metamorphism near Prieska and the Kheis domain has become entrenched in the literature as a major late Palaeoproterozoic orogenic belt which has had a significant impact on the interior of the Kaapvaal Craton (e.g. Duane and Kruger, 1991;.…”

Section: Comparative Geochronologymentioning

confidence: 98%

Evolution of the Namaqua-Natal Belt, southern Africa – A geochronological and isotope geochemical review

Eglington

2006

Journal of African Earth Sciences

170

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Section: Comparative Geochronologymentioning

confidence: 98%

Evolution of the Namaqua-Natal Belt, southern Africa – A geochronological and isotope geochemical review

Eglington

2006

Journal of African Earth Sciences

170

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“…Cornell (1998) obtained a 1750 + 60 Ma Rb-Sr biotite-whole-rock date on a pristine dolerite (Mamutlan dolerite) which intrudes the Hartley basalts and concluded that the Kheisian fabric must be older than this date. Humphreys and Cornell (1989) described high grade metamorphism within the Kheis domain and the Kheis domain has become entrenched in the literature as a major late-Palaeoproterozoic orogenic belt which has had significant impact on the interior of the Kaapvaal Craton e.g. Duane et al (1991a; and Thomas et al (1994).…”

Section: Regional Summary -The Kaapvaal Craton and Surroundingsmentioning

confidence: 99%

The Kaapvaal Craton and adjacent orogens, southern Africa: a geochronological database and overview of the geological development of the craton

Eglington

2004

South African Journal of Geology

171

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Geochronological comparisons of large datasets are facilitated by the use of structured databases. Data for the Precambrian of South Africa, Swaziland, Lesotho and Botswana have been compiled in a DateView database and linked to chronostratigraphy and GIS databases to produce a series of 'time-slice' maps illustrating the development of the Kaapvaal Craton. Linking geochronological data to GIS coverages provides a valuable visual perspective on the development of the southern African lithosphere. The oldest preserved rock formation dates occur south of the Barberton Greenstone Belt in South Africa and Swaziland. Subsequent scattered development of new crust occurred in the south eastern, eastern and northern Kaapvaal Craton before being 'stitched' together by extensive granitoid intrusions at ~3.25 Ga and ~3.1 Ga. Coeval development of new crust occurred in what would later become the central zone of the Limpopo Belt. The patterns of igneous activity from ~3.1 Ga to ~2.8 Ga, outboard of major cratonic lineaments (Colesberg lineament in the west and Thabazimbi-Murchison lineament in the north) may indicate that these lineaments represent suture zones along which the younger domains were accreted during formation of the Kaapvaal Craton. By ~3 Ga the lithosphere was sufficiently rigid to support development of the Dominion, Witwatersrand and Pongola sedimentary basins, followed by extensive volcanism during the Ventersdorp and concomitant granitoid activity throughout the Craton. Subsequent geological activity, not necessarily evident in the available geochronological record, was concentrated on craton with the development of the widespread Transvaal Supergroup followed by essentially coeval extrusion of the Rooiberg felsites and intrusion of the Bushveld Complex at ~2.06 Ga. Deposition of sediments comprising the Waterberg and Soutpansberg Groups followed. Igneous activity along the southwestern edge of the Kaapvaal Craton terminated at ~1.93 Ga with formation of the Hartley basalts, Olifantshoek Supergroup. Post-Olifantshoek Supergroup and pre-Volop Group tectonism has been reported from the western margin of the Kaapvaal Craton. There is currently no geochronological evidence for major igneous or metamorphic activity postdating formation of the Olifantshoek Supergroup until the early stages of the Namaqua-Natal Belt subsequent to ~1.4 Ga i.e. there is no geochronological evidence for a major late-Palaeoproterozoic 'Kheisian orogeny'. Off-craton, new crust formed in the Richtersveld Sub-province at ~1.8 Ga but was presumably only accreted to the Kaapvaal Craton some 700 million years later during the Namaqua-Natal orogenesis. Figure 2. Selected views of the DateView user interface, illustrating the steps typically followed when extracting data from the database. The query illustrated selects all crystallization dates for both the Witwatersrand and Kimberley terrains for the period from 1950 Ma to 3550 Ma. One of the 159 records found with this query is shown in step b. Other tabsheets provide access to additional ...

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“…Low-pressure mafic granulites in reworked Archaean basement near the Kaapvaal Craton margin have yielded a Rb-Sr whole-rock isochron date of 1353 _+33Ma, which may reflect an early extensional event affecting the continental margin (Humphreys & Cornell 1989). A Sm-Nd garnet-whole-rock isochron date of 1215 +50Ma constrains the timing of prograde amphibolite facies metamorphism in the juvenile arc terrane to the west and is inferred to record crustal thickening during arc accretion (Cornell et al 1990b(Cornell et al , 1992.…”

Section: Namaqua-natal Orogenmentioning

confidence: 99%

“…An important segment of the Namaqua Belt that Raith & Cornell (2000); 17, Cornell et al (1990aCornell et al ( , b, 1992; 18, Humphreys & Cornell (1989);19, Gutzmer et al (2000); 20, Tack Thomas & Eglington (1990), Thomas et al (1993), Cornell et al (1996), McCourt et al (2000.…”

Section: Namaqua-natal Orogenmentioning

confidence: 99%

Proterozoic geochronology and tectonic evolution of southern Africa

Hanson

2003

157

129

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The Precambrian foundation of southern Africa consists of Archaean cratonic nuclei surrounded by belts formed during three separate Proterozoic orogenic episodes. Crust that formed or was reworked at 2.05-1.8Ga is represented by orogenic belts (e.g. Kheis-Magondi, Ubendian-Usagaran) that partly wrap the ancient craton margins or form extensive basement in younger belts. Orogenic belts formed at 1.35-1.0Ga record arc magmatism and collisional events during assembly of the Rodinia supercontinent. The Namaqua-Natal Belt defines a major convergent plate boundary active at this time along the southern margin of the Archaean Kaapvaal Craton, and the western part of this belt is inferred to link with a largely buried, NE-trending orogen present in the Kalahari region. Orogenesis in the same time frame farther north is recorded by the Kibaran and Irumide Belts, which are separated by the Palaeoproterozoic Bangweulu Block but are inferred to have undergone a linked tectonic evolution. East of the Irumide Belt, extensive Mesoproterozoic arc crust occurs in Malawi and Mozambique, although strong Neoproterozoic overprinting of the arc rocks makes their original relations unclear. Breakup of Rodinia is signalled by widespread Neoproterozoic alkaline and bimodal magmatism associated with rift zones which, in some cases, evolved into major ocean basins. Subsequent amalgamation of Gondwana led to collisional orogenesis culminating at 575-505 Ma in the Mozambique and West Congo-Kaoko-Gariep-Saldania Belts along the present eastem and western margins of southern Africa. Coeval deformation in the interconnecting, transcontinental Damara-Lufilian-Zambezi Orogen may reflect destruction of linked rifts and narrow ocean basins driven by farfield stresses from the collisional plate margins.

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Petrology and geochronology of low-pressure mafic granulites in the Marydale Group, South Africa

Cited by 13 publications

References 27 publications

Evolution of the Namaqua-Natal Belt, southern Africa – A geochronological and isotope geochemical review

Evolution of the Namaqua-Natal Belt, southern Africa – A geochronological and isotope geochemical review

The Kaapvaal Craton and adjacent orogens, southern Africa: a geochronological database and overview of the geological development of the craton

Proterozoic geochronology and tectonic evolution of southern Africa

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