Plate Tectonic Reconstructions of the Cretaceous and Cenozoic Ocean Basins (Paleoceanographic Mapping Project Progress Report No. 34-1287)

In this paper we present nine reconstructions for the Mesozoic and Cenozoic, based on the sea-floor spreading isochrons published by Larson et al. (1985). The purpose of this study was: 1) to determine if the isochrons drawn by Larson et al. (1985) could be refitted to produce a self-consistent set of plate tectonic reconstructions, 2) to use the areas of apparent mismatch between magnetic isochrons as a focus for further investigations, and 3) to test the capabilities and accuracy of interactive computer graphic methods of plate tectonic reconstruction. In general, Tertiary and Late Cretaceous isochrons could be refitted reasonably well; however, closure errors were apparent in the vicinity of the Bouvet and Macquarie triple junctions. It was not possible to produce Early Cretaceous reconstructions that were consistent with the isochrons drawn by Larson et al. (1985). In this paper we also propose that the Late Cretaceous and early Tertiary plate reorganizations observed in the Indian Ocean were the result of the progressive subduction of an intraTethyan rift system.