U-Pb isotopic evidence for episodic granitoid emplacement in the Murchison greenstone belt, South Africa

✍ Scribed by M. Poujol

• Book ID: 104354097
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 805 KB
• Volume: 33
• Category: Article
• ISSN: 1464-343X
• DOI: 10.1016/s0899-5362(01)90096-x

✦ Synopsis

This study presents new single-zircon U-Pb data that constrain the timing of granitoid emplacement within and to the south of the Murchison greenstone belt, South Africa. Four main magmatic events are identified at ca 3020, 2970, 2820 and 2680 Ma for the Baderoukwe, Discovery, Willie and Mashishimale intrusions, respectively. The age of 3020 Ma, found for the Baderoukwe Pluton, which is intrusive into the Letaba, Bawa and Sable schist belts, suggests that the schist belts are older than 3020 Ma. The age of the Discovery Granite is identical to that of the rhyodacitic Rubbervale Formation, suggesting that granite magmatism was associated with volcanism in the Murchison greenstone belt at around 2970 Ma. The emplacement of the Willie

Granite is contemporaneous with several other granites on the Kaapvaal Craton, suggesting that there was a major period of felsic magmatism on the craton between 2820 and 2880 Ma. The 2700 Ma Mashishimale Granite reflects, furthermore, the age of many of the late-stage potassic granite plutons on the Kaapvaal Craton, indicating that this period was also an important crustforming event.