Growing Gondwana and rethinking Rodinia: A paleomagnetic perspective

The formation of Gondwana during the late Neoproterozoic to early Cambrian times (550-530 Ma) was traditionally viewed as the welding of two, more or less contiguous, Proterozoic continental masses called East and West Gondwa na. The notion of a united West Gondwana is no longer tenable as a wealth o f geochronologic and structural data indicate major orogenesis amongst its constituent cratons during the final stages of greater Gondwana assembly. T he idea that East Gondwana may also have formed through the amalgamation of a collage of cratonic nuclei during the Cambrian is controversial. Recent paleomagnetic, geochronologic and structural data from elements of East Gon dwana indicate that its formation may have extended well into Cambrian time . Thus, the terms 'East' and 'West' Gondwana may be relegated to convenient geographical terms rather than any connotation of tectonic coherence durin g the Proterozoic. In addition, the paleomagnetic data also challenge the c onventional views of the Neoproterozoic supercontinent Rodinia and the SWEA T fit. Alternative variants including Protopangea and AUSWUS are not suppor ted by paleomagnetic data during the interval 800-700 Ma.