An Archaean continental assembly of the South Indian and Western Australian Cratons (SIWA)

What is it about?

Analysis of palaeomagnetic database of the Palaeoproterozoic dykes of India indicates that during the geological time period from 2500 to 1800 the South Indian craton moved from high latitude to an equatorial position. Mafic dykes of ~2400 Ma age from the Western Australia and the South India provide evidence for the juxtaposition of the Yilgarn craton against the east coast of India. The events stratigraphy of the South Indian and the Yilgarn cratons are also found to be identical up to ~2100 Ma. The palaeomagnetic data, events stratigraphy and matching configuration of the east coast of India and the west coast of Western Australia for the time period >2100 Ma suggest for the existence of a supercontinental block “SIWA”. The Indian dykes of 2100-1800 Ma were possibly related to the breaking of the supercontinental block at ~2000 Ma.

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Why is it important?

The paper reviews and integrates geological and geochronological data from India and the Western Australia and suggests: 1. existence of a pre-Rodinian cratonic nuclei “SIWA” before 2400 Ma; 2. the break-up of SIWA at ~2000 Ma giving rise to palao-Indian ocean; 3. the sedimentation of the Cuddapah Supergroup in a rift-valley / passive margin set up; 4. the separation of the Yilgarn craton from the South Indian craton and its northward movement lead to the development of a collisional mountain along the Capricorn orogen at ~1800 Ma.