YN #2. 700 km Norseman GRS on Landsat. New paradigm for Yilgarn exploration.
This paper describes research on the Norseman Giant Ring Structure (GRS). The GRS was visible on Landsat, despite limited geological outcrop and woodland and semi-desert sandplain cover. The Kambalda ring is a particularly persistent 1000 km arc. The Norseman GRS is unaffected by the regional geology. The relatively undeformed rings suggest that the lower crust was, and has remained, rigid. Outpouring of huge volumes of lava onto this rigid lower crust may have been similar to the formation of the Mares on top of the Moon. Greenstones and mineralisation follow the rings. The giant mines at Kalgoorlie, St Ives and Kambalda are on the dark margins of the rings and Norseman lies right in the centre. The Vredefort dome caused a giant gold and uranium province and the Sudbury structure has one of the world’s biggest nickel fields. How would this mineralisation be remobilized under 15 – 20km of overlying crust? How and where would it be deposited? The Chicxulub impact structure exhibits similar features to the Yilgarn Craton GRS. Giant ring structures in Archaean Cratons have not been recorded or researched. This places a major constraint on the current Yilgarn Craton research.
