DOI: 10.1016/j.epsl.2018.06.009
Scopus记录号: 2-s2.0-85048714879
论文题名: Pliocene erosional pulse and glacier-landscape feedbacks in the western Alaska Range
作者: Lease R.O.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 497 起始页码: 62
结束页码: 68
语种: 英语
英文关键词: Alaska
; erosional feedback
; glacial erosion
; glacier-landscape feedbacks
; Plio–Pleistocene glaciation
; thermochronometry
Scopus关键词: Apatite
; Catchments
; Feedback
; Fission reactions
; Geometry
; Glacial geology
; Landforms
; Silicate minerals
; Tectonics
; Temperature
; Topography
; Zircon
; Alaska
; Apatite fission tracks
; Catchment topography
; Glacial erosion
; Glacier mass balance
; Lower temperatures
; Pleistocene
; Thermochronometry
; Erosion
; glacial erosion
; glacial landform
; glaciation
; glacier dynamics
; landscape change
; Pliocene-Pleistocene boundary
; thermochronology
; Alaska
; Alaska Range
; United States
英文摘要: Pliocene–Pleistocene glaciation modified the topography and erosion of most middle- and high-latitude mountain belts, because the evolution of catchment topography controls long-term glacier mass balance and erosion. Hence, characterizing how erosion rates change during repeated glaciations can help test hypothesized glacier erosion-landscape feedbacks across a range of settings. To better understand how glaciations and landscapes coevolve on geologic timescales, I quantify erosion rates in the glaciated western Alaska Range with low-temperature thermochronometric data and modeling. Zircon (U–Th)/He and apatite fission track data suggest mountain-building was underway by the early Miocene. In contrast, lower-temperature apatite (U–Th)/He age-elevation and grain age-kinetic data indicate that erosion accelerated coincident with regional Pliocene glaciation ca. 4 Ma. Furthermore, erosion rates calculated within an eroding half-space indicate slow erosion at a rate ≤0.3 km/m.y. before 4.2 Ma, an initial pulse of rapid erosion at a rate of 1.0–1.6 km/m.y. during 4.2–2.9 Ma, and more moderate erosion at a rate of 0.4–0.7 km/m.y. since 2.9 Ma. The initial erosion pulse suggests a significant transient landscape adjustment to the introduction of efficient glacial erosion. The subsequent decrease in Pleistocene erosion rates is consistent with a negative feedback between continuing glaciation and glacier size/erosivity: If glacial erosion outpaces rock uplift, glacier erosion decreases over time as topography, mass balance, valley gradients, and ice flux are reduced. These findings imply that in areas of moderate rock uplift rates, the onset of local Plio–Pleistocene glaciation may have been punctuated by an initial pulse of rapid landscape change, after which change became more gradual. © 2018 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109783
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: U.S. Geological Survey, Anchorage, AK 99508, United States
Recommended Citation:
Lease R.O.. Pliocene erosional pulse and glacier-landscape feedbacks in the western Alaska Range[J]. Earth and Planetary Science Letters,2018-01-01,497