Publication Type:Journal Article
Source:GeologyGeology, Geological Society of America, Volume 39, Number 5, p.487-490 (2011)
Keywords:Apatite, Binary alloys, Gallium, geochronology, Lead alloys, Repair, Uranium alloys
Proterozoic reconstructions of the Kaapvaal and Zimbabwe cratons have been limited by the scarcity of precisely dated paleomagnetic poles for the Zimbabwe craton. We present new U-Pb baddeleyite and apatite dates from two diabase sheets that have previously yielded paleomagnetic data from the Mashonaland igneous province in the Zimbabwe craton. Discordant baddeleyite analyses yield upper intercept dates of 1871.9 2.2 and 1882.7 +1.6/-1.5 Ma. Apatite data from the same samples give less precise but statistically indistinguishable dates, providing direct constraints on the post-magmatic thermal history of the diabases. The new U-Pb dates and other recently published baddeleyite dates from the Mashonaland province are coeval with mafic magmatism in the adjacent Kaapvaal craton (1879-1872 Ma), but paleomagnetic poles from the two intraplate suites differ by 39, suggesting that the two cratons underwent substantial relative motion after ca. 1.88 Ga. Paleomagnetic reconstructions are consistent with 2000 km of lateral displacement being accommodated in the Limpopo orogenic belt that separates the two cratons. 2011 Geological Society of America.
Compilation and indexing terms, Copyright 2018 Elsevier Inc.<br/>20111613930004<br/>Igneous province<br/>Lateral displacements<br/>Orogenic belts<br/>Paleomagnetic data<br/>Paleomagnetic poles<br/>Relative motion<br/>Thermal history<br/>Zimbabwe Craton