Diapirism initiated by the Bushveld Complex, South Africa

Abstract

Research Article| August 01, 1997 Diapirism initiated by the Bushveld Complex, South Africa Ronald Uken; Ronald Uken 1Department of Geology and Applied Geology, University of Natal, Durban 4041, South Africa Search for other works by this author on: GSW Google Scholar Michael K. Watkeys Michael K. Watkeys 1Department of Geology and Applied Geology, University of Natal, Durban 4041, South Africa Search for other works by this author on: GSW Google Scholar Author and Article Information Ronald Uken 1Department of Geology and Applied Geology, University of Natal, Durban 4041, South Africa Michael K. Watkeys 1Department of Geology and Applied Geology, University of Natal, Durban 4041, South Africa Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (8): 723–726. https://doi.org/10.1130/0091-7613(1997)025<0723:DIBTBC>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Ronald Uken, Michael K. Watkeys; Diapirism initiated by the Bushveld Complex, South Africa. Geology 1997;; 25 (8): 723–726. doi: https://doi.org/10.1130/0091-7613(1997)025<0723:DIBTBC>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The Bushveld Complex induced the development of a unique type of diapir during its intrusion. These diapirs are preserved as large domal structures exposed on the margin and within the northeastern mafic layered sequence. They were produced by gravitational loading and heating of argillaceous and arenaceous floor rocks. Gravity-induced deformation is restricted to rocks above a detachment level that corresponds approximately with the 550 °C peak-metamorphic isotherm and with lithological contacts of contrasting competency. Strongly foliated and boudinaged contact-metamorphosed sedimentary rocks between domes were deformed by lateral extension along flow lines directed toward dome culminations. At the highest structural levels, domes have bulbous geometries and the enclosing layered igneous rocks are deformed into series of outward-verging folds that define a broad rim syncline. Deformation within the domal cores is represented by constriction that produced radial curtain-type folds that have steeply plunging lineations and concentrically oriented folds in the outer shell. Diapirism is closely linked to magma emplacement mechanisms. Floor folds in the country rocks were initiated in the interfinger areas of a fingered intrusion. With the coalescence of intrusion fingers into a single sheet, interfinger folds matured into large diapiric domes that rose to the upper levels of the magma chamber. Strain rates estimated from strain analyses, dome geometry, and model cooling calculations are on the order of 10−14 s−1, corresponding to diapiric uplift rates of 0.6 cm/yr. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.