Geochronological constraints on the Hartbees River Thrust and Augrabies Nappe: New insights into the assembly of the Mesoproterozoic Namaqua-Natal Province of Southern Africa

Colliston, W.P.; Cornell, David H.; Schoch, A.E.; Praekelt, H.E.

doi:10.1016/j.precamres.2015.03.008

Cited by 30 publications

(13 citation statements)

References 34 publications

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“…In contrast, the westernmost Kalahari Craton shows dominance of igneous and metamorphic 1.2-1.0 Ga old rocks from the Namaqua-Natal Belt (Eglington, 2006;Jacobs et al, 2008;Hofmann et al, 2014), which are derived from older Meso-and Paleoproterozoic crust as indicated by Sm-Nd and Hf T DM model ages (e.g., Pettersson et al, 2009;Cornell et al, 2012;Colliston et al, 2015). Even though some Paleoproterozoic basement inliers are present as well, they yield dominant Paleoproterozoic Sm-Nd T DM model ages (Pettersson et al, 2009).…”

Section: The Nico Pérez Terrane and Its Crustal Affinitymentioning

confidence: 99%

The Nico Pérez Terrane (Uruguay): From Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton

Oriolo

Oyhantçabal

Basei

et al. 2016

Precambrian Research

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Section: The Nico Pérez Terrane and Its Crustal Affinitymentioning

confidence: 99%

The Nico Pérez Terrane (Uruguay): From Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton

Oriolo

Oyhantçabal

Basei

et al. 2016

Precambrian Research

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“…The Hartbees River Thrust is the western most thrust fault in the study area and trends NW‐SE before deviating E‐W and running parallel to the Orange River [ Colliston et al ., ]. The generally E‐W structural trend of the western section of the study area is best represented by the Tantalite Valley shear zone, Groothoek Thrust, and, further south, Buffels River shear zone.…”

Section: Geomorphology and Geologymentioning

confidence: 99%

Contrasting Mesozoic evolution across the boundary between on and off craton regions of the South African plateau inferred from apatite fission track and (U‐Th‐Sm)/He thermochronology

et al. 2017

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The timing and mechanisms involved in creating the elevated, low‐relief topography of the South African plateau remain unresolved. Here we constrain the thermal history of the Southwest African plateau since 300 Ma by using apatite fission track (AFT) and (U‐Th‐Sm)/He (AHe) thermochronology. Archean rocks from the center of the Kaapvaal Craton yield AFT ages of 331.0 ± 11.0 and 379.0 ± 23.0 Ma and mean track lengths (MTLs) of 11.9 ± 0.2 and 12.5 ± 0.3 µm. Toward the southwest margin of the craton and in the adjacent Paleozoic mobile belt, AFT ages are significantly younger and range from 58.9 ± 5.9 to 128.7 ± 6.3 Ma and have longer MTLs (>13 µm). The range of sample AHe ages complements the AFT ages, and single‐grain AHe ages for most samples are highly dispersed. Results from joint inverse modeling of these data reveal that the center of the craton has resided at near‐surface temperatures (<60°C) since 300 Ma, whereas the margins of the craton and the off‐craton mobile belt experienced two discrete episodes of cooling during the Cretaceous. An Early Cretaceous cooling episode is ascribed to regional denudation following continental breakup. Late Cretaceous cooling occurs regionally but is locally variable and may be a result of a complex interaction between mantle‐driven uplift and the tectonic setting of the craton margin. Across the entire plateau, samples are predicted to have remained at near‐surface temperatures throughout the Cenozoic, suggesting minimal denudation (<1 km) and relative tectonic stability of the plateau.

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“…Locally, magmatic foliation suggests the late-tectonic emplacement of the Naros pluton (Bial et al, 2015b). A similar situation exists further east along the Hartebees River shear zone, where the Karama'am Granite (1,106 ± 8 Ma) truncates its mylonitic structure (Colliston et al, 2015). For the Grünau area in neighboring Namibia, Bial et al (2016) provide a more accurate estimate of the time of deformation along regional shear zones.…”

Section: Geological Context and Regional Crustal Evolutionmentioning

confidence: 90%

Petrogenesis of Mesoproterozoic Granites of the Swartoup Hills Region, Kakamas Domain, Namaqua Belt, South Africa

2021

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The Swartoup and Polisiehoek plutons in the Swartoup Hills (South Africa) formed during an episode of significant magma emplacement in the Mesoproterozoic Namaqua Sector of the Namaqua Metamorphic Province. They intruded into mid-crustal metasedimentary rocks of the metapelitic Koenap and mafic to carbonate-bearing Bysteek Formations during and shortly after the ∼1,200–1,220 Ma regional metamorphic peak that reached ultrahigh temperatures. Subsequent to pluton emplacement, the crust underwent regional high-temperature deformation during slow near-isobaric cooling. A further episode of pluton emplacement associated with fluid circulation truncated the first-order regional tectonic structures at ∼1,100 Ma. Based on their petrography, the Swartoup pluton is subdivided into leuco-granitoids with biotite as the sole mafic phase, pyroxene granitoids, and garnet-bearing granitoids, which may contain significant biotite. These subgroups display distinctive geochemical variations from one another, and from the Koenap Formation migmatites and the Polisiehoek granites, which are exposed nearby. Incompatible trace element distributions suggest that the Swartoup and Polisiehoek granitoids represent modified A-type granite magma, consistent with derivation from partial melting of quartzo-feldspathic crust. The magmas incorporated significant amounts of juvenile mantle-derived magma (εNd1200 of ∼−5, and LREE-depleted), but do not require older, early to late Paleoproterozoic crust. Particularly close to contacts to the calcic Bysteek Formation, localized contamination of the Swartoup granites by supracrustal carbonates is evident. A relatively pervasive alkali metasomatic effect is manifested strongly in the initial 87Sr/86Sr and LILE profiles of the Polisiehoek granites in particular, as well as in some of the Swartoup pyroxene granitoids, which could be either a symptom of CO2 metasomatism related to the Bysteek Formation carbonates, or to post-magmatic fluid metasomatism, perhaps linked to regional shearing. The comparison of our results with literature data suggests that similar sources, A-type granitic, Meso- to Paleoproterozoic crustal, and enriched mantle, have contributed, in locally differing proportions, to granites in most parts of the Namaqua Sector. Most likely, these plutons were generated during crustal and mantle melting in a long-lived hot continental back-arc environment.

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Geochronological constraints on the Hartbees River Thrust and Augrabies Nappe: New insights into the assembly of the Mesoproterozoic Namaqua-Natal Province of Southern Africa

Cited by 30 publications

References 34 publications

The Nico Pérez Terrane (Uruguay): From Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton

The Nico Pérez Terrane (Uruguay): From Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton

Contrasting Mesozoic evolution across the boundary between on and off craton regions of the South African plateau inferred from apatite fission track and (U‐Th‐Sm)/He thermochronology

Petrogenesis of Mesoproterozoic Granites of the Swartoup Hills Region, Kakamas Domain, Namaqua Belt, South Africa

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