U-Pb geochronology and paleomagnetism of the Westerberg sill, Kaapvaal Craton - Support for Vaalbara into the Paleoproterozoic
2014 (English)Conference paper, Presentation (Refereed)
Precise geochronology combined with paleomagnetism provides first-order information necessary for paleoreconstructions of crustal blocks and for revealing the history of supercontinent formation and break-up. These techniques are used here in an attempt to further constrain the apparent polar wander path of the Kaapvaal craton through the Neoarchean and Paleoproterozoic. A new baddeleyite U-Pb age of 2440.2 ± 5.9 Ma for the intracratonic Westerberg sill manifests a new event of mafic magmatism within the Kaapvaal Craton of southern Africa and falls in the center of a ca. 450 Ma gap in the paleomagnetic record, between 2.66 and 2.22 Ga. The Westerberg sill is coeval with the Woongarra sills on the Pilbara craton and intrudes into a remarkably similar sedimentary succession, hence supporting a coherent Kaapvaal-Pilbara block (i.e., Vaalbara) spanning the Archean-Proterozoic boundary interval. The coeval Westerberg-Woongarra igneous event may represent a large igneous province, here recognized for the first time on the Kaapvaal craton. The virtual geomagnetic pole obtained for the Kaapvaal craton for the Westerberg sill fits well into a large gap of the craton’s apparent polar wander path. Furthermore, combined with a coeval Pilbara pole, it allows for a reconstruction of Vaalbara that places Pilbara in relative close proximity and to the north of the Kaapvaal craton.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:ltu:diva-39580Local ID: e65b6243-101f-4d2f-9933-d305c1bb58caOAI: oai:DiVA.org:ltu-39580DiVA: diva2:1013094
GSA annual meeting : 19/10/2014 - 22/10/2014
Upprättat; 2014; 20150212 (tobkam)2016-10-032016-10-03