Post-orogenic shoshonitic magmas of the Yzerfontein pluton, South Africa: the 'smoking gun' of mantle melting and crustal growth during Cape granite genesis?

The post-orogenic Yzerfontein pluton, in the Saldania Belt of South Africa was constructed through numerous injections of shoshonitic magmas. Most magma compositions are adequately modelled as products of fractionation, but the monzogranites and syenogranites may have a separate origin. A separate high-Mg mafic series has a less radiogenic mantle source. Fine-grained magmatic enclaves in the intermediate shoshonitic rocks are autoliths. The pluton was emplaced between 533 ± 3 and 537 ± 3 Ma (LASF-ICP-MS U–Pb zircon), essentially synchronously with many granitic magmas of the Cape Granite Suite (CGS). Yzerfontein may represent a high-level expression of the mantle heat source that initiated partial melting of the local crust and produced the CGS granitic magmas, late in the Saldanian Orogeny. However, magma mixing is not evident at emplacement level and there are no magmatic kinships with the I-type granitic rocks of the CGS. The mantle wedge is inferred to have been enriched during subduction along the active continental margin. In the late- to post-orogenic phase, the enriched mantle partially melted to produce heterogeneous magma batches, exemplified by those that formed the Yzerfontein pluton, which was further hybridized through minor assimilation of crustal materials. Like Yzerfontein, the small volumes of mafic rocks associated with many batholiths, worldwide, are probably also lowvolume, high-level expressions of crustal growth through the emplacement of major amounts of mafic magma into the deep crust.IS

The Bereznajkovskoje gold trend, southern Urals - a discussion.

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Melt induced changes in emplacement style during progressive batholith assembly: the 3.1 Ga Heerenveen batholith, South Africa.

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The stabilization of self-organised leucogranite networks - Implications for melt segregationand far-field melt transfer in the continental crust

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Changing emplacement styles during the Progressive assembly of the ca.3.1 GA Heerenveen Batholith, Barberton Granitoid-Greenstone Terrain, South Africa

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Steep extrusion of late-Archaean granulites in the Northern Marginal Zone, Zimbabwe: evidence for secular changes in orogenic style.

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Syntectonic emplacement and deformation of the Heerenveen batholith: Conjectures on the structural setting of the 3.1 Ga granite magmatism in the Barberton granite-greenstone terrain, South Africa.

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Incremental assembly and changing emplacement styles recorded in the 3.1 Ga sheeted Heerenveen batholith, Barberton granitoid-greenstone terrain, South Africa.

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Fold collapse and crustal extrusion above syntectonic granite sheets: field examples from the south Central Zone of the Damara Belt, Namibia.

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