A Fragment of Columbia Supercontinent: Insight for Cathaysia Block Basement From Tectono-Magmatic Evolution and Mantle Heterogeneity

The origin of the Cathaysia block and its position in Columbia supercontinent are still enigmatic. Paleoproterozoic magmatisms developed in the Cathaysia block due to two episodes of continental back-arc extension range in ages of circa 1.88-1.85 and 1.78-1.77 Ga. A long-lived ultradepleted mantle domain with highly incompatible element depletion related to average depleted mantle once underlaid the Cathaysia block is revealed by the highly depleted Hf-Nd isotopes of the Paleoproterozoic meta-mafic rocks. A self-consistent set of geological, geochronological, and geochemical data indicate that the Cathaysia was assembled and then maintained a position off the southern margin of North Australia Craton from the assembly to the accretion of Columbia supercontinent (circa 1.90 to 1.74 Ga). Given the evidence for Cathaysia block, mantle heterogeneity might provide an alternative approach of supercontinent reconstruction.