TELLING TIME OR TELLING LIES? PROTEROZOIC APPARENT POLAR WANDER PATHS

Testing proposed continental reconstructions as a prelude to constraining plate motions in the Proterozoic is dependent on the quality/quantity of paleomagnetic data. Considering the most recent supercontinent, data density and coverage for the individual blocks that comprise Pangea are variable. Presumably, the notion that Pangea assembly resulted from the collision of a coherent Gondwana with a coherent Laurasia should be a simple matter. While most can agree that Pangea existed during the latter part of the Paleozoic, its exact shape and evolution during the Carboniferous and Permian are still debated. The data density (not necessarily quality) is orders of magnitude better than for the much more divided elements that comprise the Rodinia (~1000 Ma) or Columbia (~1700 Ma) supercontinents. Reconstructions for these older supercontinents are dependent on the vagaries of paleomagnetic data including longitudinal freedom, polarity choice and robustness of the geochronology. Despite these limitations, numerous attempts are made to create/fit apparent polar wander paths to particular configurations of Rodinia and Columbia. In this talk, we discuss the good, the bad and the ugly and outline the status of paleomagnetically controlled reconstructions in the Proterozoic.