The South Pacific Superswell

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This "accomplishment-based-renewal" provides funds for Dr. McNutt to continue research on two closely related projects awarded her by MG&G; both pertain to the study of anomalous elevations of ocean crust beneath the Pacific. The first of these features is the South Pacific Superswell, a large area of seafloor as much as 750m shallower than predicted by its age relative to the 125km-thick cooling plate model of Parsons and Sclater. Previous analysis by Dr. McNutt discount both local density and dynamic stress field anomalies as the fundamental cause; a plate model thinned to 75 km and accompanied by small- scale convection in the underlying asthenosphere is favored. This renewal will allow her to complete the write-up phase of this analysis, and to evaluate the model by writing computer code that will model this convective flow and test its stability. The Darwin Rise is a second depth anomaly studied under a previous award, and Dr. McNutt and colleagues argue it was formed by the same processes that created the Superwell. She will continue analysis of isostatic compensation surrounding Mesozoic guyots surveyed on a recent cruise across the Darwin Rise with the objective of gaining better understanding of mantle dynamics.