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Active Tectonics And Ultrahigh-Pressure Rocks, Ann Blythe

Ann Blythe

This chapter compares modern exhumation and surface uplift rates with the rates needed for the preservation of ultrahigh pressure (UHP) metamorphic rocks. The highest recorded exhumation rates of ~ 5–10 mm/a are inferred from isotopic and fission-track analyses in the Himalaya, Southern Alps of New Zealand, and D’Entrecasteaux Islands. Similar rates (~7 mm/a) of surface uplift are measured from leveling surveys in Nepal and correlations of marine terraces in the Southern Alps. In Nepal, however, this surface uplift rate is occurring despite erosion, and the true rate of surface uplift is probably considerably higher. In restraining bends along the San …