The Grenvillian Namaqua fold belt adjacent to the western Kaapvaal Craton: 2. Archaean Craton and supercontinent connections

Colliston, W.P.; Schoch, A.E.; Cole, Janine

doi:10.1016/j.precamres.2017.07.032

Cited by 11 publications

(18 citation statements)

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“…The southern portion of the Gordonia Subprovince extends to the Kenhardt region, where it disappears beneath younger Palaeozoic cover rocks [13]. The Gordonia Subprovince is transected by Mesoproterozoic faults and shear zones trending mostly northwest-southeast (Figure 2), some of which are major structures of regional importance [1,5,6,13,16,25].…”

Section: Geological Settingmentioning

confidence: 99%

“…The 1.3-1.0 Ga Namaqua-Natal Metamorphic Province of southern Africa is part of the global Grenvillian age orogenic belts [1][2][3][4][5][6]. It was involved in the formation of the Kalahari Craton [7] and was potentially associated with the assembly of the supercontinent Rodinia [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…Regional stratigraphic and structural studies have, however, confirmed that the subprovinces host a number of tectonostratigraphic domains distinguished based on tectonic history, metamorphic grade and lithostratigraphic criteria, and separated by regional scale structural discontinuities. Although there is no consensus on the number of, or names for, these domains, summaries are given by [5,11,13,15,16]. In this paper, we follow the subdivisions and nomenclature of [13] and [16].…”

Section: Introductionmentioning

confidence: 99%

“…However, we prefer to use the non-genetic term "Domain" instead of "Terrane", as in [13], which is associated with a precise genetic definition related to accretionary tectonics (see [17]). The domain of interest in this study is the Kakamas Domain (Grünau Terrane of [5,15]), which is a prominent tectonic feature in the eastern Namaqua Sector (Figure 1). The Namaqua Sector is composed of severely deformed medium-to high-grade metamorphosed supracrustal and magmatic rocks and borders the western margin of the Archean Kaapvaal Craton in South Africa [3,6,13,[18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…The Namaqua Sector is composed of severely deformed medium-to high-grade metamorphosed supracrustal and magmatic rocks and borders the western margin of the Archean Kaapvaal Craton in South Africa [3,6,13,[18][19][20][21][22]. Various geological [1,6,11,15,[23][24][25][26][27][28], geophysical [5,[29][30][31], and geochronological [3,4,22,[32][33][34][35][36][37][38] investigations suggest that the Namaqua-Natal Metamorphic Province was dominated by both compressional and extensional events during the 1.2-1.0 Ga Namaquan Orogeny (correlated with the Grenvillian). [13]).…”

Section: Introductionmentioning

confidence: 99%

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Polyphase Deformation of the High-Grade Metamorphic Rocks along the Neusspruit Shear Zone in the Kakamas Domain: Insights into the Processes during the Namaquan Orogeny at the Eastern Margin of the Namaqua Metamorphic Province, South Africa

2021

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The central part of the Namaqua Metamorphic Province was subjected to intense deformation under high-grade metamorphic conditions up to granulite facies, but also shows greenschist facies overprints denoting the metamorphic nature during the 1.2–1.0 Ga Namaquan Orogeny. This study examines the structural development of the central Kakamas Domain of the eastern Namaqua Metamorphic Province, which has not been extensively studied previously. The compressional orogenic phase is associated with D1 and D2 deformation events during which northeast–southwest-directed shortening resulted in southwest-directed thrusting illustrated by an intra-domain thrust and southwest-verging isoclinal folds. The post-tectonic Friersdale Charnockite of the Keimoes Suite is emplaced during the D3 deformation event. Late reactivation of the intra-domain thrust in the Kakamas Domain to form the Neusspruit Shear Zone during the D4 event is of a monoclinic nature and is described as a deeply rooted structure with shear direction towards the east. This structure, together with the more local Neusberg Thrust Fault, forms part of an intensely flattened narrow basin in the eastern Namaqua Metamorphic Province. Strain and vorticity indices suggest a transpressional shearing across the Neusspruit Shear Zone and adjacent regions probably initiated during the reactivation of the intra-domain thrust. The ~1.2 to 1.8 km-wide, northwest–southeast striking dextral-dominated Neusspruit Shear Zone constitutes a western regional boundary for the supracrustal Korannaland Group and is composed of steep, narrow zones of relatively high strain, characterised by ductile deformation and penetrative strain.

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Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Polyphase Deformation of the High-Grade Metamorphic Rocks along the Neusspruit Shear Zone in the Kakamas Domain: Insights into the Processes during the Namaquan Orogeny at the Eastern Margin of the Namaqua Metamorphic Province, South Africa

2021

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Syn-metamorphic sulfidation of the Gamsberg zinc deposit, South Africa

Höhn

Frimmel

Price³

2021

Miner Petrol

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The Mesoproterozoic Aggeneys-Gamsberg ore district, South Africa, is one of the world´s largest sulfidic base metal concentrations and well-known as a prime example of Broken Hill-type base metal deposits, traditionally interpreted as metamorphosed SEDEX deposits. Within this district, the Gamsberg deposit stands out for its huge size and strongly Zn-dominated ore ( >14 Mt contained Zn). New electron microprobe analyses and element abundance maps of sulfides and silicates point to fluid-driven sulfidation during retrograde metamorphism. Differences in the chemistry of sulfide inclusions within zoned garnet grains reflect different degrees of interaction of sulfides with high metal/sulfur-ratio with a sulfur-rich metamorphic fluid. Independent evidence of sulfidation during retrograde metamorphism comes from graphic-textured sulfide aggregates that previously have been interpreted as quenched sulfidic melts, replacement of pyrrhotite by pyrite along micro-fractures, and sulfides in phyllic alteration zones. Limited availability of fluid under retrograde conditions caused locally different degrees of segregation of Fe-rich sphalerite into Zn-rich sphalerite and pyrite, and thus considerable heterogeneity in sphalerite chemistry. The invoked sulfur-rich metamorphic fluids would have been able to sulfidize base metal-rich zones in the whole deposit and thus camouflage a potential pre-metamorphic oxidation. These findings support the recently established hypothesis of a pre-Klondikean weathering-induced oxidation event and challenge the traditional explanation of Broken Hill-type deposits as merely metamorphosed SEDEX deposits. Instead, we suggest that the massive sulfide deposits experienced a complex history, starting with initial SEDEX-type mineralization, followed by near-surface oxidation with spatial metal separation, and then sulfidation of this oxidized ore during medium- to high-grade metamorphism.

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