Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Gerya, T. V. Articles by Clarke, B. M. Search for Related Content GeoRef GeoRef Citation

Cold fingers in a hot magma: Numerical modeling of country-rock diapirs in the Bushveld Complex, South Africa

¹ Institut of Geology, Mineralogy and Geophysics, Ruhr-University Bochum, 44780 Bochum, Germany, and Institute of Experimental Mineralogy, Russian Academy of Sciences, 142432 Chernogolovka, Moscow, Russia
² School of Geological and Computer Science, University of Natal, Durban, 4041, South Africa
³ Institut of Geology, Mineralogy and Geophysics, Ruhr-University Bochum, 44780 Bochum, Germany
⁴ Council for Geoscience, P.O. Box 900, 3200, Pietermaritzburg, South Africa

Partially molten diapirs and domes in Earth's continental crust can be an effective means of transporting heat from lower to higher levels, often producing pronounced prograde metamorphic aureoles. Our numerical thermomechanical models show that this classical thermal scenario is violated by the diapirs of partially molten metasedimentary rocks to 8 km in diameter that penetrate the Bushveld Complex, the world's largest layered intrusion. Here, diapirism was triggered by the emplacement of an 8-km-thick, hot, and dense mafic magma over a cold and less dense sedimentary succession. These diapirs promoted cooling of the giant magma chamber, bringing cooler material into higher crustal levels. Comparison between numerical results and geological observations indicates that diapir nucleation is crucially dependent on the presence of initial topographic disturbances between 800 and 1000 m in height in the floor of the magma chamber, and also allows critical parameters of initial geometry and temperature distribution of the Bushveld event to be outlined.

Key Words: diapirism • numerical modeling • Bushveld Complex • partial melting • plumes • subduction zones

This article has been cited by other articles:

				B. M. Clarke, R. Uken, M. K. Watkeys, and J. Reinhardt Folding of the Rustenburg layered suite adjacent to the Steelpoort pericline: implications for syn-Bushveld tectonism in the eastern Bushveld Complex South African Journal of Geology, September 1, 2005; 108(3): 397 - 412. [Abstract] [Full Text] [PDF]