Journal ArticleDOI
New U–Pb geochronologic and palaeomagnetic constraints on the late Palaeoproterozoic Hartley magmatic event: evidence for a potential large igneous province in the Kaapvaal Craton during Kalahari assembly, South Africa
Farnaz Alebouyeh Semami,Michiel O. de Kock,Ulf Söderlund,Ashley Gumsley,Richard da Silva,N.J. Beukes,Richard Armstrong +6 more
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In this paper, the age and palaeopole of the Hartley Formation were derived for the mafic and felsic phases of a large-scale 1.93-1.91-Ga bimodal magmatism on the Kaapvaal Craton.Abstract:
The volcanic Hartley Formation (part of the Olifantshoek Supergroup, which is dominated by red bed successions) in South Africa recorded depositional and tectonic conditions along the western Kaapvaal Craton during the late Palaeoproterozoic. It formed in association with red bed deposition elsewhere in the cratonic hinterland and along the craton’s northern margin. However, the exact correlation of the Olifantshoek Supergroup with these other red-bed successions is hindered by poor geochronological constraints. Herein, we refine the age and palaeopole of the Hartley Formation, and provide geochronological constraints for large-scale 1.93–1.91 Ga bimodal magmatism on the Kaapvaal Craton (herein named the Hartley large igneous province). We present new age constraints for the mafic and felsic phases of this event at 1923 ± 6 Ma and 1920 ± 4 Ma, respectively, which includes the first reported age dating of the Tsineng Dyke Swarm that has been linked to Hartley volcanism. A mean 1.93–1.91 Ga palaeoma...read more
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Large Igneous Province Record Through Time and Implications for Secular Environmental Changes and Geological Time-Scale Boundaries
Richard E. Ernst,Richard E. Ernst,David P.G. Bond,Shuan-Hong Zhang,Kenneth L. Buchan,Stephen E. Grasby,Nasrrddine Youbi,Nasrrddine Youbi,Nasrrddine Youbi,Hafida El Bilali,Andrey Bekker,Andrey Bekker,Luc Serge Doucet +12 more
Journal ArticleDOI
Turmoil before the boring billion: Paleomagnetism of the 1880–1860 Ma Uatumã event in the Amazonian craton
Paul Yves Jean Antonio,Paul Yves Jean Antonio,Manoel S. D’Agrella-Filho,Ricardo I.F. Trindade,Anne Nédélec,Davis Carvalho de Oliveira,Fernando Fernandes da Silva,Matteo Roverato,Cristiano Lana +8 more
TL;DR: The Uatuma silicic large igneous province (SLIP) has covered about 1,500,000 km 2 of the Amazonian craton at ca. 1880-Ma, when the Columbia/Nuna supercontinent has been assembled.
Journal ArticleDOI
Baddeleyite U–Pb ages and gechemistry of the 1875–1835 Ma Black Hills Dyke Swarm across north-eastern South Africa: part of a trans-Kalahari Craton back-arc setting?
TL;DR: In this paper, 11 new baddeleyite U-Pb crystallisation ages and associated whole-rock geochemistry on NE-NNE-trending tholeiitic dykes cutting across the north-eastern corner of the Archaean Kaapvaal Craton, the overlying Transvaal basin and the Bushveld and Phalaborwa igneous complexes collectively define a 1875-1835-Ma Black Hills Dyke Swarm (BHDS).
Journal ArticleDOI
U–Pb baddeleyite geochronology and geochemistry of the White Mfolozi Dyke Swarm: unravelling the complexities of 2.70–2.66 Ga dyke swarms across the eastern Kaapvaal Craton, South Africa
TL;DR: In this paper, the White Mfolozi Dyke Swarm (WMDS) has been identified on the south-easternmost Kaapvaal Craton, a NE-trending plagioclase-megacrystic dolerite dyke swarm.
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J.S. Stacey,Jan Kramers +1 more
TL;DR: In this paper, a two-stage model for terrestrial lead isotope evolution is proposed, which permits the age of the earth to be that of the meteorite system and also yields good model ages for samples of all ages.
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The least-squares line and plane and the analysis of palaeomagnetic data
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Precision Measurement of Half-Lives and Specific Activities of U 235 and U 238
TL;DR: New determinations of the half-lives of half-life values of $ −235 and −238 have been made improved techniques have allowed the halflife values to be measured with greater accuracy than has been heretofore achieved as discussed by the authors.
Journal ArticleDOI
Precise U‐Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System
James B. Paces,James D. Miller +1 more
TL;DR: In this article, anorthositic and gabbroic intrusives were chosen to represent both the temporal and spatial ranges of plutonic activity that formed the Duluth Complex and related mafic intrusions.
Journal ArticleDOI
U‐Pb geochronology of zircons from lunar breccia 73217 using a sensitive high mass‐resolution ion microprobe
TL;DR: In this paper, the age of four zircons from thin-sections of one highland breccia, 73217, using the recently constructed ion microprobe SHRIMP was determined.