Mid-Pleistocene climate transition drives net mass loss from rapidly uplifting St. Elias Mountains, Alaska

作者：S. P. S. Gulick, J. M. Jaeger, Alan C Mix, Hirofumi Asahi, Heinrich Bahlburg, Christina L. Belanger, Glaúcia Bueno Benedetti Berbel, Laurel B. Childress, Ellen A. Cowan, Laureen Drab, Matthias Forwick, Akemi Fukumura, Shulan Ge, Shyam M. Gupta, Arata Kioka, Susumu Konno, Leah J. LeVay, Christian März, Kenji M. Matsuzaki, Erin L. McClymont, Christopher M. Moy, Juliane Müller, Atsunori Nakamura, Takanori Ojima, F. Rodrigues Ribeiro, Kenneth D. Ridgway, Oscar E Romero, Angela L. Slagle, Joseph S. Stoner, Guillaume St‐Onge, Itsuki Suto, Maureen H. Walczak, L. L. Worthington, Ian Bailey, Eva Enkelmann, R. Reece, J. M. Swartz · 发表于：Proceedings of the National Academy of Sciences · 年份：2015 · DOI：10.1073/pnas.1512549112 · 被引用次数：104 · 研究领域：Geology and Paleoclimatology Research、Climate change and permafrost、Cryospheric studies and observations

Erosion, sediment production, and routing on a tectonically active continental margin reflect both tectonic and climatic processes; partitioning the relative importance of these processes remains controversial. Gulf of Alaska contains a preserved sedimentary record of the Yakutat Terrane collision with North America. Because tectonic convergence in the coastal St. Elias orogen has been roughly constant for 6 My, variations in its eroded sediments preserved in the offshore Surveyor Fan constrain a budget of tectonic material influx, erosion, and sediment output. Seismically imaged sediment volumes calibrated with chronologies derived from Integrated Ocean Drilling Program boreholes show that erosion accelerated in response to Northern Hemisphere glacial intensification (∼ 2.7 Ma) and that the 900-km-long Surveyor Channel inception appears to correlate with this event. However, tectonic influx exceeded integrated sediment efflux over the interval 2.8-1.2 Ma. Volumetric erosion accelerated following the onset of quasi-periodic (∼ 100-ky) glacial cycles in the mid-Pleistocene climate transition (1.2-0.7 Ma). Since then, erosion and transport of material out of the orogen has outpaced tectonic influx by 50-80%. Such a rapid net mass loss explains apparent increases in exhumation rates inferred onshore from exposure dates and mapped out-of-sequence fault patterns. The 1.2-My mass budget imbalance must relax back toward equilibrium in balance with tectonic influx over the timescale ...