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Archaean evolution of the Wongan Hills Greenstone Belt, Yilgarn Craton, Western Australia

 

作者: R. T. Pidgeon,   S. A. Wilde,   W. Compston,   M. W. Shield,  

 

期刊: Australian Journal of Earth Sciences  (Taylor Available online 1990)
卷期: Volume 37, issue 3  

页码: 279-292

 

ISSN:0812-0099

 

年代: 1990

 

DOI:10.1080/08120099008727927

 

出版商: Taylor & Francis Group

 

关键词: Archaean evolution;greenstone belts;Yilgarn Craton

 

数据来源: Taylor

 

摘要:

Ion microprobe and conventional U‐Pb analyses on single zircons from a felsic porphyry from the Wongan Hills Greenstone Belt in the Western Gneiss Terrain of Western Australia define an age of 3010 ± 7 Ma. This is a minimum age for volcanism in the greenstone belt. A sample of gneiss from near the belt contains two populations of zircons with ages of 2997 ± 47 Ma and 2800 ± 9 Ma. Theca3.0 Ga zircons are interpreted as dating the formation of the granitic parent of the gneiss, and theca2.8 Ga zircons are interpreted as dating gneiss formation. This latter event may be an early manifestation of the major 2.65–2.75 Ga granite‐greenstone episode which affected the entire Yilgarn Craton and is expressed at Wongan Hills by the emplacement of post‐tectonic porphyritic granite dated at 2651 ± 4 Ma, and greenschist facies retrogressive metamorphism, dated at 2646 ± 11 Ma by U‐Pb analyses of cogenetic sphene. The present results confirm the significance ofca3.0 Ga volcanism in the north and western Yilgarn Craton and suggest that this event was coeval with granitoid emplacement. No zircons older than 3.0 Ga, which would support models for an older crustal origin for these rocks, were found in the present samples.

 

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