Contrasting crustal evolution processes in the Dharwar craton: Insights from detrital zircon U–Pb and Hf isotopes

• Terrane accumulation in the Dharwar craton began ~ 3 Ga in older Western block.
• Final cratonisation at 2.5 Ga is much later than other Archaean cratons.
• Tectonic, not genetic, links with the Kaapvaal and north China cratons.

New in situ U–Pb-Hf analyses of detrital zircons from across the Archaean Dharwar craton indicate significant juvenile crustal extraction events at ~ 3.3 and 2.7 Ga, and continuous extraction from 3.7 to 3.3 Ga. Reworking in the older western block at ~ 3.0 Ga marks the onset of cratonisation, most likely due to ‘modern’ plate tectonic processes, whilst reworking in both the western and younger eastern block at 2.55–2.50 Ga indicates accretion of the two terranes and final cratonisation much later than in most other Archaean terranes (~ 2.7 Ga). Different patterns of disturbance to the zircon U–Pb systematics reflect variations in both the U content of parent rocks and later metamorphic conditions. Tectonic links are observed between the Kaapvaal and western Dharwar cratons, and between the north China and eastern Dharwar cratons, though none of these links necessarily requires a consanguineous origin.

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