Thrust exhumation of the Neoarchean ultrahigh-temperature Southern Marginal Zone, Limpopo Complex: Convergence of decompression-cooling paths in the hanging wall and prograde P-T paths in the footwall

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dc.contributor.authorVan Reenen D.D.
dc.contributor.authorSmit C.A.
dc.contributor.authorPerchuk L.L.
dc.contributor.authorRoering C.
dc.contributor.authorBoshoff R.
dc.date.accessioned2011-10-13T16:59:41Z
dc.date.available2011-10-13T16:59:41Z
dc.date.issued2011
dc.description.abstractIntegrated structural, metamorphic, and geochronological data indicate that the evolution of the Southern Marginal Zone (SMZ) of the Limpopo Complex of southern Africa was controlled by a single Neoarchean high-grade tectono-metamorphic event. The exhumation history refl ected by the high-grade rocks is determined by their location relative to the contact with the low-grade rocks of the Kaapvaal Craton. Exhumation of granulites far north from this contact is recorded by a decompressioncooling (DC) pressure-temperature (P-T) path linked to steep southward-verging thrusts related to the Hout River Shear Zone. This P-T path traverses from P ∼8 kbar, T ∼825 °C to P ∼5 kbar, T ∼550 °C and refl ects exhumation of the SMZ in the interval ca. 2.68-2.64 Ga. P-T paths for granulites close to this contact are characterized by a distinct infl ection at P ∼6 kbar, T ∼700 °C that exhibits near-isobaric cooling (IC) to T ∼580 °C. The IC stage is linked to low-angle, out-of-sequence, southward-verging thrusts that developed in the interval 2.63-2.6 Ga. The thrust-controlled exhumation of the SMZ furthermore is demonstrated by the convergence at P ∼6 kbar, T ∼700 °C of DC P-T paths in the hanging wall with prograde P-T loops in the footwall of the steeply southward-verging Hout River Shear Zone, and by the establishment of a retrograde isograd and zone of rehydrated granulites in the hanging wall derived from the dehydration of the low-grade rocks in the footwall. A composite deformation-pressure-temperature-time (D-P-T-t) diagram provides evidence in support of a tectonic model for the evolution of the Limpopo Complex that involves early crustal thickening and peak metamorphic conditions followed by doming and diapirism related to gravitational redistribution mechanisms. © 2011 The Geological Society of America.
dc.description.versionArticle
dc.identifier.citationMemoir of the Geological Society of America
dc.identifier.citation207
dc.identifier.citationhttp://www.scopus.com/inward/record.url?eid=2-s2.0-80051864798&partnerID=40&md5=d9ecebad30e669e7966368b7cdafa58d
dc.identifier.issn721069
dc.identifier.other10.1130/2011.1207(11)
dc.identifier.urihttp://hdl.handle.net/10019.1/17204
dc.titleThrust exhumation of the Neoarchean ultrahigh-temperature Southern Marginal Zone, Limpopo Complex: Convergence of decompression-cooling paths in the hanging wall and prograde P-T paths in the footwall
dc.typeArticle
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