WHAT'S UP WITH RODINIA?

The mineralogy and geochemistry associated with the assembly of Rodinia are significantly different from those of other supercontinents. Rodinian assembly (~1.3 to 0.9 Ga) is relatively enriched in Nb minerals, Y minerals, and zircon, with corresponding enrichments of trace Nb, Y, and Zr in igneous rocks. By contrast, it is significantly depleted in minerals of many other elements (e.g., Ni, Co, Au, Se, and Platinum group elements), without corresponding depletion of trace Ni and Co in igneous rocks. The Nb, Y, and Zr enrichments result from significant ‘within-plate’ magmatism during mid-Proterozoic, while the depletions of many other minerals suggest enhanced erosion of Rodinian orogens. A unique tectonic setting during the assembly of Rodinia can account for both the prevalence of ‘within-plate’ magmatism and the enhanced erosion.