Abstract

We propose that there has been little or no Pliocene-Pleistocene uplift of the dry valleys sector of the Transantarctic Mountains, on the basis of isotopic dating and mapping of in situ cinder-cone deposits on the walls of Taylor Valley. Twenty-seven 40Ar/39Ar incremental heating analyses on whole-rock samples from subaerially erupted olivine basanite volcanic outcrops of known elevations define 14 eruptions ranging in age from 3.89 to 1.50 Ma. Because Taylor Valley opens directly onto the Ross Sea, these results show that any surface uplift during the past 2.57 m.y. was <300 m. Our conclusion of minimal uplift contradicts previous models of dramatic uplift (up to 3000 m since 3 Ma) and associated hypotheses that uplift caused climatic cooling and growth of a polar East Antarctic ice sheet.

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