Extensional tectonics and the fragmentation of Gondwanaland

Abstract
Summary: Evidence of widespread lithospheric extension, bimodal volcanism, and uplift and erosion, accompanying the fragmentation of Gondwanaland, is reviewed. One regime of extensional phenomena appears to be intimately associated with a Pacific-margin convergent-plate regime. A second appears to bear no direct geometrical relationship to the margin, but may reflect a thermal anomaly that resulted in the breakup of Gondwanaland. Possible causes of this anomaly are discussed. The two regimes overlap in space and time in the South Atlantic-Weddell Sea area. A causal relationship between the two is possible but remains non-proven.