PROTEROZOIC PALEOGEOGRAPHY OF TARIM BLOCK: AN EXTENDED OR ALTERNATIVE "MISSING-LINK" MODEL FOR RODINIA?

Recent reconstructions of Rodinia supercontinent breakup incorporate South China as a "missing link" between Australia and Laurentia, and Tarim craton adjacent to northern Australia on the supercontinent’s periphery. Subsequent kinematic evolution toward Gondwana amalgamation, however, poses complex geometric shuffling between South China and Tarim, not easily compatible with the stratigraphic records of those blocks. Here we present new paleomagnetic data from early Ediacaran strata of northwestern Tarim, documenting large-scale rotation at near-constant paleolatitudes during Cryogenian time. The rotation is coeval with Rodinia breakup, and Tarim's paleolatitudes are compatible with its reconstruction between Australia and Laurentia, either as a second "missing link" with South China, or by itself in that role. At the same time, indications of subduction-related magmatism in Tarim's Neoproterozoic record suggest that Rodinia breakup was dynamically linked to subduction retreat along its northern margin. Such a model is akin to early stages of Jurassic fragmentation within southern Gondwana, and implies more complicated dynamics of supercontinent breakup than superplume impingement alone.