Constraints on Archaean crustal evolution of the Zimbabwe craton: a U-Pb zircon, Sm-Nd and Pb-Pb whole-rock isotope study

Jelsma, Hielke A.; Vinyu, M.L.; Wijbrans, J. R.; Verdurmen, E.A.Th.; Valbracht, Peter J.; Davies, Gareth R.

doi:10.1007/s004100050173

Cited by 99 publications

(85 citation statements)

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“…Banded gneisses along the western margin of the Murehwa batholith have been dated by Baldock and Evans (1988) at 2865135 Ma (Rb±Sr whole rock), suggesting that these form basement-to-the-greenstone sequence. Gneissic granitoids near the eastern margin of the Chinamora batholith have been dated by the same authors at 2680102 Ma (Rb±Sr whole rock) and by Jelsma et al (1996) at 26674 Ma (U±Pb TIMS zircon). Late syn-to post-tectonic granodiorites and tonalites, intrusive into the greenstone belt, have yielded U±Pb TIMS zircon ages of 266415 Ma (Mazowe), 26496 Ma (Bindura) and 26186 Ma (Glendale; Jelsma et al 1996).…”

Section: Field Relationships and Sample Localitiesmentioning

confidence: 99%

“…The age of the volcanics is bracketed between 2715 and 2643 Ma ( Fig. 1; Wilson et al 1995;Jelsma et al 1996).…”

Section: Field Relationships and Sample Localitiesmentioning

confidence: 99%

“…Shown are the main lithological units, excluding the mid-Proterozoic dolerite intrusions. Localities 1±15 refer to the following age data: granite±gneiss terrain, 1±3.2, 2.9, 2.8 Ga (Pb±Pb±zir-con Kober age): granitoid clasts in Shamvaian sediments; 2±2865135 Ma (Rb±Sr wholerock age; Baldock and Evans 1988): banded gneiss; 3±2680 104 Ma (Rb±Sr whole-rock age; Baldock and Evans 1988): granodioritc gneiss; 4±2667 4 Ma (U±Pb±zircon TIMS age; Jelsma et al 1996): granitic gneiss; 5±266415 Ma (U±Pb± zircon TIMS age; Jelsma et al 1996): granodiorite; 6±2649 2 Ma (U±Pb±zircon TIMS age; Jelsma et al 1996): granodiorite; 7±2646 +36/±37 Ma (Pb±Pb whole-rock age; Jelsma et al 1996): granodiorite; 8±26186 Ma (U±Pb±zir-con TIMS age; Jelsma et al 1996): tonalite; 9±260114 Ma (U±Pb±zircon TIMS age; Jelsma et al 1996): granite; greenstones, 10±271515 Ma (U±Pb-zircon TIMS age; Jelsma et al 1996): rhyolite; 11±26979 Ma (Pb±Pb±zircon SHRIMP age; Wilson et al 1995): felsic tuff; 12±2672 12 Ma (U±Pb±zircon TIMS age; Jelsma et al 1996): andesitic porphyry; 13±2659 + 38/±39 Ma (Pb±Pb whole-rock age): siliceous felsic volcanics; 14±26454 Ma (Pb±Pb±zircon SHRIMP age; Wilson et al 1995): rhyolite; 15±26438 Ma (Pb±Pb±zircon SHRIMP age; Wilson et al 1995): felsic clasts in tuff…”

Section: Introductionmentioning

confidence: 99%

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Constraints on the timing of granite emplacement, deformation and metamorphism in the Shamva area, Zimbabwe

et al. 2001

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In order to constrain the temporal relationship between granite (sensu lato) emplacement and metamorphism, isotope work was carried out on the minerals zircon and apatite (U±Pb), garnet (Pb±Pb) and hornblende (Ar±Ar) from wall rock samples in the Shamva area in Zimbabwe. The area, encompassing parts of the Chinamora and Murehwa batholiths and a wedge-shaped greenstone belt segment in between, is commonly quoted in the literature as an example illustrating pluton emplacement processes and deformational models for the Archean. New U±Pb dating of apatite from a boudinaged pegmatite within mafic schists in the batholith±greenstone contact zone has yielded an age of 2619 +28/±24 Ma. This age is interpreted as the best estimation of the intrusion age of this unit, depending on the assumed closure temperature, and provides an upper age limit for the syntectonic emplacement of the now gneissic granites. Pb±Pb dating of late kinematic garnets in cordierite-bearing rocks within the greenstone belt wall rocks gives an age of 26238 Ma. Together, this timing of relatively late, syntectonic plutonism and metamorphic mineral growth at ca. 2.62 Ga compares well with existing zircon crystallization ages for felsic volcanics (26454 Ma, 26438 Ma) and post-tectonic porphyritic monzogranites (260114 Ma). Ar±Ar hornblende ages for mafic schists from different areas within the greenstone belt wall rocks range between 2621 and 2498 Ma and have been interpreted to indicate mixing between metamorphic ages and cooling ages. The data support a geological model whereby volcanism and sedimentation are associated with an early phase of regional deformation at ca. 2.64 Ga, which may have started earlier and lasted longer, and evolves into the voluminous emplacement of granites (now gneissic granites) in the batholiths at approximately 2.62 Ga. Emplacement of post-tectonic tabular monzogranites takes place at ca. 2.60 Ga.

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Section: Field Relationships and Sample Localitiesmentioning

confidence: 99%

“…The age of the volcanics is bracketed between 2715 and 2643 Ma ( Fig. 1; Wilson et al 1995;Jelsma et al 1996).…”

Section: Field Relationships and Sample Localitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Constraints on the timing of granite emplacement, deformation and metamorphism in the Shamva area, Zimbabwe

et al. 2001

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“…1). The time of deposition is unknown, but age determinations of adjacent rocks in various greenstone belts bracket sedimentation to between 2.68 and 2.64 Ga (Jelsma et al, 1996;Wilson et al, 1995). The Shamvaian Group is similar to modern foreland and forearc successions and formed during compressional or transtensional tectonics associated with accretionary processes Hofmann et al, 2004).…”

Section: Geology Of the Zimbabwe Cratonmentioning

confidence: 99%

“…Frei et al, 1999;Jelsma et al, 1996;Jelsma and Dirks, 2002), followed by intrusion of the layered igneous complex of the Great Dyke at 2.575 Ga (Oberthür et al, 2002).…”

Section: Geology Of the Zimbabwe Cratonmentioning

confidence: 99%

Juvenile crust formation in the Zimbabwe Craton deduced from the O-Hf isotopic record of 3.8–3.1 Ga detrital zircons

Bolhar

Hofmann

Kemp

et al. 2017

Geochimica et Cosmochimica Acta

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Neodymium isotope constraints on provenance, dispersal, and climate‐driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years

Lubbe

Tjallingii

Schneider³

2016

Geochem Geophys Geosyst

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Marine sediments deposited off the Zambezi River that drains a considerable part of the southeast African continent provide continuous records of the continental climatic and environmental conditions. Here we present time series of neodymium (Nd) isotope signatures of the detrital sediment fraction during the past 45,000 years, to reconstruct climate-driven changes in the provenance of clays deposited along the Mozambique Margin. Coherent with the surface current regime, the Nd isotope distribution in surface sediments reveals mixing of the alongshore flowing Zambezi suspension load with sediments supplied by smaller rivers located further north. To reconstruct past changes in sediment provenances, Nd isotope signatures of clays that are not significantly fractionated during weathering processes have been obtained from core 64PE304-80, which was recovered just north of the Zambezi mouth at 1329 m water depth. Distinctly unradiogenic clay signatures (E Nd values <214.2) are found during the Last Glacial Maximum, Heinrich Stadial 1, and Younger Dryas. In contrast, the Nd isotope record shows higher, more radiogenic isotope signatures during Marine Isotope Stage 3 and between 15 and 5 ka BP, the latter coinciding with the timing of the northern hemisphere African Humid Period. The clay-sized sediment fraction with the least radiogenic Nd isotope signatures was deposited during the Holocene, when the adjacent Mozambique Shelf became completely flooded. In general, the contribution of the distinctly unradiogenic Zambezi suspension load has followed the intensity of precession-forced monsoonal precipitation and enhanced during periods of increased southern hemisphere insolation and high-latitude northern hemispheric climate variability.

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Constraints on Archaean crustal evolution of the Zimbabwe craton: a U-Pb zircon, Sm-Nd and Pb-Pb whole-rock isotope study

Cited by 99 publications

References 0 publications

Constraints on the timing of granite emplacement, deformation and metamorphism in the Shamva area, Zimbabwe

Constraints on the timing of granite emplacement, deformation and metamorphism in the Shamva area, Zimbabwe

Juvenile crust formation in the Zimbabwe Craton deduced from the O-Hf isotopic record of 3.8–3.1 Ga detrital zircons

Neodymium isotope constraints on provenance, dispersal, and climate‐driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years

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