title: Mid-Pleistocene climate transition drives net mass loss from rapidly uplifting St. Elias Mountains, Alaska.
abstract: 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 of orogenic wedge response (millions of years). The St. Elias Range provides a key example of how active orogenic systems respond to transient mass fluxes, and of the possible influence of climate-driven erosive processes that diverge from equilibrium on the million-year scale.
authors.affiliation: Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758-4445; sean@ig.utexas.edu.
authors.forename: Sean P S
authors.identifier: http://orcid.org/0000-0003-4740-9068
authors.initials: SP
authors.lastname: Gulick
authors.affiliation: Department of Geological Sciences, University of Florida, Gainesville, FL 32611-2120;
authors.forename: John M
authors.initials: JM
authors.lastname: Jaeger
authors.affiliation: College of Oceanic & Atmospheric Sciences, Oregon State University, Corvallis, OR 97331-5503;
authors.forename: Alan C
authors.initials: AC
authors.lastname: Mix
authors.affiliation: Korea Polar Research Institute, Incheon 406-840, Korea;
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Asahi
authors.affiliation: Institut für Geologie und Paläontologie, Universität Münster, 48149 Muenster, Germany;
authors.forename: Heinrich
authors.initials: H
authors.lastname: Bahlburg
authors.affiliation: Department of Geology and Geological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701;
authors.forename: Christina L
authors.initials: CL
authors.lastname: Belanger
authors.affiliation: Departamento de Oceanografia Física, Química e Geológica, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, SP 05508-120, Brazil;
authors.forename: Glaucia B B
authors.initials: GB
authors.lastname: Berbel
authors.affiliation: Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL 60208;
authors.forename: Laurel
authors.initials: L
authors.lastname: Childress
authors.affiliation: Department of Geology, Appalachian State University, Boone, NC 28608;
authors.forename: Ellen
authors.initials: E
authors.lastname: Cowan
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964;
authors.forename: Laureen
authors.initials: L
authors.lastname: Drab
authors.affiliation: Department of Geology, Universitetet i Tromsø, Tromso 9037, Norway;
authors.forename: Matthias
authors.initials: M
authors.lastname: Forwick
authors.affiliation: Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8601, Japan;
authors.forename: Akemi
authors.initials: A
authors.lastname: Fukumura
authors.affiliation: Department of Marine Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, People's Republic of China;
authors.forename: Shulan
authors.initials: S
authors.lastname: Ge
authors.affiliation: National Institute of Oceanography, Dona Paula, Goa 403 004, India;
authors.forename: Shyam
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Atmosphere and Ocean Research Institute, University of Tokyo, Chiba 277-8564, Japan;
authors.forename: Arata
authors.identifier: http://orcid.org/0000-0002-0922-1112
authors.initials: A
authors.lastname: Kioka
authors.affiliation: Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581, Japan;
authors.forename: Susumu
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authors.lastname: Konno
authors.affiliation: International Ocean Discovery Program, Texas A&M University, College Station, TX 77845-9547;
authors.forename: Leah J
authors.initials: LJ
authors.lastname: LeVay
authors.affiliation: School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom;
authors.forename: Christian
authors.initials: C
authors.lastname: März
authors.affiliation: Department of Geology and Paleontology, Tohoku University, Sendai 980-8578, Japan;
authors.forename: Kenji M
authors.identifier: http://orcid.org/0000-0001-8918-9249
authors.initials: KM
authors.lastname: Matsuzaki
authors.affiliation: Department of Geography, University of Durham, Durham DH1 3LE, United Kingdom;
authors.forename: Erin L
authors.initials: EL
authors.lastname: McClymont
authors.affiliation: Department of Geology, University of Otago, Dunedin 9054, New Zealand;
authors.forename: Chris
authors.initials: C
authors.lastname: Moy
authors.affiliation: Marine Geology and Paleontology, Alfred Wegener Institute, 27568 Bremerhaven, Germany;
authors.forename: Juliane
authors.initials: J
authors.lastname: Müller
authors.affiliation: Atmosphere and Ocean Research Institute, University of Tokyo, Chiba 277-8564, Japan;
authors.forename: Atsunori
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Atmosphere and Ocean Research Institute, University of Tokyo, Chiba 277-8564, Japan;
authors.forename: Takanori
authors.initials: T
authors.lastname: Ojima
authors.affiliation: Departamento de Oceanografia Física, Química e Geológica, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, SP 05508-120, Brazil;
authors.forename: Fabiana R
authors.initials: FR
authors.lastname: Ribeiro
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN 47907-2051;
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Ridgway
authors.affiliation: MARUM - Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany;
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Romero
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964;
authors.forename: Angela L
authors.initials: AL
authors.lastname: Slagle
authors.affiliation: College of Oceanic & Atmospheric Sciences, Oregon State University, Corvallis, OR 97331-5503;
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Stoner
authors.affiliation: Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, Rimouski, QC, Canada G5L 3A1;
authors.forename: Guillaume
authors.initials: G
authors.lastname: St-Onge
authors.affiliation: Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8601, Japan;
authors.forename: Itsuki
authors.initials: I
authors.lastname: Suto
authors.affiliation: Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia;
authors.forename: Maureen D
authors.initials: MD
authors.lastname: Walczak
authors.affiliation: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131;
authors.forename: Lindsay L
authors.initials: LL
authors.lastname: Worthington
authors.affiliation: Camborne School of Mines, College of Engineering, Mathematics & Physical Sciences, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom;
authors.forename: Ian
authors.initials: I
authors.lastname: Bailey
authors.affiliation: Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013;
authors.forename: Eva
authors.initials: E
authors.lastname: Enkelmann
authors.affiliation: Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843-3115.
authors.forename: Robert
authors.initials: R
authors.lastname: Reece
authors.affiliation: Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758-4445;
authors.forename: John M
authors.initials: JM
authors.lastname: Swartz
keywords: Mid-Pleistocene transition; mass flux; ocean drilling; orogenesis; tectonic−climate interactions