A stable isotope record of late Cenozoic surface uplift of southern Alaska

作者：Bill Nicholas S^*; Mix Hari T; Clark Peter U; Reilly Sean P; Jensen Britta J L; Benowitz Jeffrey A

来源：Earth and Planetary Science Letters, 2018, 482: 300-311.

DOI：10.1016/j.epsl.2017.11.029

• Alaska
• surface uplift
• stable isotopes
• paleoenvironmental change
• hydrologic cycle
• paleoaltimetry

Although the timing of an acceleration in late-Cenozoic exhumation of southern Alaska is reasonably well constrained as beginning similar to 5-similar to 6 Ma, the surface uplift history of this region remains poorly understood. To assess the extent of surface uplift relative to rapid exhumation, we developed a stable isotope record using the hydrogen isotope composition (delta D) of paleo-meteoric water over the last similar to 7 Ma from interior basins of Alaska and Yukon Territory. Our record, which is derived from authigenic clays (delta D-clay) in silicic tephras, documents a similar to 50 similar to 60 parts per thousand increase in delta D values from the late Miocene (similar to 6-similar to 7 Ma) through the Plio-Pleistocene transition (similar to 2-similar to 3 Ma), followed by near-constant values over at least the last similar to 2 Ma. Although this enrichment trend is opposite that of a Rayleigh distillation model typically associated with surface uplift, we suggest that it is consistent with indirect effects of surface uplift on interior Alaska, including changes in aridity, moisture source, and seasonality of moisture. We conclude that the delta D-clay record documents the creation of a topographic barrier and the associated changes to the climate of interior Alaska and Yukon Territory.

• 出版日期2018-1-15