Paleomagnetic study of NeoArchean-Paleoproterozoic dykes in the Kaapvaal Craton

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dc.contributor.authorLubnina N.
dc.contributor.authorErnst R.
dc.contributor.authorKlausen M.
dc.contributor.authorSoderlund U.
dc.date.accessioned2011-05-15T16:03:49Z
dc.date.available2011-05-15T16:03:49Z
dc.date.issued2010
dc.description.abstract431 oriented samples were collected from 27 dolerite dykes at 17 sites, belonging to 2.95, 2.65, and 1.90. Ga swarms, that trend SE, E and NE, respectively from the Bushveld Igneous Complex into the eastern Kaapvaal Craton (ages determined by Olsson et al., 2010; Olsson in Söderlund et al., 2010). Samples were analyzed for paleomagnetism and also anisotropy of magnetic susceptibility (AMS). For the 2.95. Ga SE-trending dykes high temperature/coercivity 'P' component has unblocking temperatures up to 590°C and coercivity 40-90. mT and demonstrate SSW declination and intermediate positive inclination. Based on positive contact and conglomerate tests we argue for a primary origin of this component. The paleopole (BAD), calculated from '. P' component, does not correspond to any of the previously obtained Archean-Paleoproterozoic paleopoles for the Kaapvaal Craton, and represents a new key pole for 2.95. Ga. The high-coercivity '. H' component for the 2.65. Ga-old E-trending dykes has a SSW declination and steep positive inclination. Paleomagnetic pole (RYK), recalculated from this component, is close to the paleopoles, obtained by Wingate (1998) and Strik et al. (2007) for 2.78. Ga Ventersdorp volcanics. The third group, NE-trending dykes of the 1.90. Ga Black Hill swarm demonstrate an '. M' component with dual polarity high-coercivity component with SSE-declination and negative intermediate inclination. The paleopole (BHD), calculated from this component is close to the 1.87. Ga pole of the Kaapvaal Craton obtained by Hanson et al. (2004). Overprint directions include a very well developed thermo-chemical overprint (Dec. =329° Inc. =-36°), which is believed to be associated with a ∼0.18. Ga regional 'Karoo' thermal event. © 2010 Elsevier B.V.
dc.description.versionArticle
dc.identifier.citationPrecambrian Research
dc.identifier.citation183
dc.identifier.citation3
dc.identifier.issn3019268
dc.identifier.other10.1016/j.precamres.2010.05.005
dc.identifier.urihttp://hdl.handle.net/10019.1/12798
dc.subjectArchean
dc.subjectbaddeleyite
dc.subjectdike
dc.subjectmagnetic anisotropy
dc.subjectmagnetic declination
dc.subjectmagnetic inclination
dc.subjectpaleomagnetism
dc.subjectProterozoic
dc.subjecttemperature
dc.subjecturanium-lead dating
dc.subjectKaapvaal Craton
dc.titlePaleomagnetic study of NeoArchean-Paleoproterozoic dykes in the Kaapvaal Craton
dc.typeArticle
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