| Title | Mesoproterozoic intraplate magmatism in the Kalahari Craton; a review |
| Author | Hanson, R.E.; Harmer, R.E.; Blenkinsop, T.G.; Bullen, D.S.; Dalziel, I.W.D.; Gose, W.A.; Hall, R.P.; Kampunzu, A.B.; Key, R.M.; Mukwakwami, J.; Munyanyiwa, H.; Pancake, J.A.; Seidel, E.K.; Ward, S.E. |
| Author Affil | Hanson, R.E., Texas Christian University, Department of Geology, Fort Worth, TX. Other: Texas Christian University; British Geological Survey, United Kingdom; Council of Geosciences, South Africa; James Cook University, Australia; University of Portsmouth, United Kingdom; University of Texas Austin; University of Botswana, Botswana; British Geological survey, United Kingdom; University of Zimbabwe, Zimbabwe |
| Source | Mesoproterozoic orogenic belts in Southern and Central Africa, edited by S. McCourt, R. Hanson and R. Key. Journal of African Earth Sciences, 46(1-2), p.141-167, . Publisher: Elsevier, Oxford, United Kingdom. ISSN: 1464-343X |
| Publication Date | Sept. 2006 |
| Notes | In English. 201 refs. GeoRef Acc. No: 284047 |
| Index Terms | Botswana; Antarctica--Queen Maud Land; absolute age; Africa; Antarctica; Ar/Ar; basalts; geochronology; IGCP; igneous rocks; intraplate processes; Kalahari Craton; mafic composition; magmatism; mantle; mantle plumes; Mesoproterozoic; nesosilicates; orogenic belts; orthosilicates; paleogeography; paleomagnetism; Precambrian; Premier kimberlite; Proterozoic; Queen Maud Land; silicates; Southern Africa; tectonics; U/Pb; Umkondo Province; upper Precambrian; volcanic rocks; zircon; zircon group |
| Abstract | The Kalahari Craton was initially stabilized following cessation of Palaeoproterozoic orogenesis in southern Africa at ca. 1.8 Ga. Subsequent Mesoproterozoic intraplate magmatism at ca. 1.4-1.35 Ga formed a series of alkaline and carbonatitic complexes in the southern part of the craton. Original volcanic structures are partly preserved in some of the complexes, and a variety of intrusive rocks (e.g., quartz syenite, nepheline syenite, pyroxenite, ijolite, carbonatite) are present. The Premier kimberlite cluster was emplaced in the same region at ca. 1.2 Ga, but available geochronology indicates that the main alkaline magmatism preceded 1.2-1.0 Ga orogenesis in the Namaqua-Natal-Maud Belt along the southern craton margin. Another, more extensive intraplate magmatic event at ca. 1.1 Ga formed the Umkondo Igneous Province, which is recognized over an area of ~2.0×106 km2 on the Kalahari Craton, including a detached fragment now located in Antarctica. Much of the province comprises high-level mafic intrusions, but erosional remnants of basalt lava piles and bimodal basalt/rhyolite assemblages are also present. Most of the mafic rocks are continental tholeiites, but trace-element geochemistry reveals distinct subgroups that cannot be related by crustal-level assimilation/fractional crystallization processes or by partial melting of a uniform mantle source. Geochronological and palaeomagnetic data indicate that enormous volumes of tholeiitic magma were emplaced within the province in a narrow time frame at ca. 1112-1106 Ma, which is inferred to record uprise of a mantle plume behind the Namaqua- Natal-Maud Belt. |
| URL | http://hdl.handle.net/10.1016/j.jafrearsci.2006.01.016 |
| Publication Type | journal article |
| Record ID | 83908 |