Entity ID: 464380 Compiled by: Stewart, A.J. Year: 2009 Status: Defined
Last Revised: 2015
Rank: province Type: tectonic Subtype: undefined Location: WA On-shore
Synonyms: NA Symbol: NA
Minimum age: Rhyacian, 2235 ± 54 Ma Age method: isotopic, Rb/Sr
Maximum age: Neoarchean, 2800 ± 240 Ma Age method: isotopic, Rb/Sr
Summary: 'Inlier' preferred by Geological Survey Western Australia because 'structural controls on the Sylvania outcrop are much more complex' than a simple dome, and because it is unconformably overlain by different groups in West, South, and East.
Area (square kilometres): 5600 State: WA Resources: Chromium Coobina deposit > 10,000 t Cr Resources: Lead One deposit < 10,000 t Pb Resources: Copper Two deposits < 10,000 t Cu; one with Zn and Ba also Resources: Gold Two deposits < 1 t Au Country: AUS
Parent: Pilbara Craton
Child Provinces: No data
Constituent units: Sylvania Dyke Swarm, metamorphosed mafic igneous rocks 74246, dolerite, metagabbro 74261, ultramafic rocks 74474
Events: No data
Mineral Deposits: Coobina
Key Reference: Tyler, I. 1991, The geology of the Sylvania Inlier and the Southeast Hamersley Basin, Geological Survey of Western Australia. Bulletin, 138, 108p Plates in pocket (see 42704) (Refid:64384)
Comments: 'Inlier' preferred by Geological Survey Western Australia because the structural controls on the Sylvania are more complex than a simple dome
Overview: Mostly granitic rock with discontinuous greenstone belts intruded by the granite. Greenstones are layered sequences of low- to medium-grade metavolcanic, mafic intrusive, and metasedimentary rocks. The largest greenstone belt, and the most complete stratigraphically, occurs within the Jimblebar greenstone belt. An ultramafic intrusion at Coobina intrudes greenstone and early granite, and hosts chromitite masses. Regarded as related to Pilbara Craton because it is basement to 2750 Ma-old rocks of Hamersley Basin, and therefore older than granite-greenstones of Yilgarn Craton.
The structural controls on the Sylvania outcrop are complex and is unconformably overlain by the Middle Proterozoic Bresnahan Group to the west, and by the Middle to Late Proterozoic Bangemall Group to the south and east.
Images: No data
Other media: No data
- FOR PROVINCE-GENERAL: Tyler, I., 1991, The geology of the Sylvania Inlier and the Southeast Hamersley Basin, Geological Survey of Western Australia. Bulletin, 138, 108p Plates in pocket (see 42704). (Refid: 64384)